MTE Inventory updates (#1496)

* MTE Inventory updates
* Separate Input/Output inventory
* Use a LinkedHashMap to ensure inventory orders are deterministic
* Input/Output work on either Input/Output inventories

* MTE Inventory

* Add GT_Packet_MultiTileEntity
* More dyanmic packet with packetFeatures
* Add IMTE_HasModes for MultiBlockPart

* Help with MTE Inventory (#1613)

* convert inventory to use ItemStackHandler
* Update MUI
* inventories
* move Iteminventory to its own method

Co-authored-by: miozune <miozune@gmail.com>

* Update MUI

* Update MUI

* Add IMultiBlockPart

* Mte fluid inventory (#1639)

* first work on fluid inventory
* make gui work with numbers not dividable by 4
* use math.min
* add outputfluids saving
* actually working
* Update MUI

Co-authored-by: miozune <miozune@gmail.com>

* Ticking Covers!
* Parts now register covers with the controller
* Controllers now tick covers on parts
* Break cover ticking out into `tickCoverAtSide`

Fix some inventory methods on MultiBlockController

* Filter on tickable covers

* Improve GUIs for MTEs (#1650)

* working controller GUI
* locked inventory selection work
* input and output locking of inventories

Co-authored-by: miozune <miozune@gmail.com>

* spotless

* CoverInfo refactor (#1654)

* Add `CoverInfo` and deprecate the old fields to hold cover information

* Disable MTE registration

* Fix NPE - Return EMPTY_INFO for SIDE_UNKNOWN

Temporarily add back old NBT saving in case of a revert so covers aren't lost.

* Actually save the old NBT data, instead of empty

Co-authored-by: BlueWeabo <76872108+BlueWeabo@users.noreply.github.com>
Co-authored-by: miozune <miozune@gmail.com>

11 files changed, 854 insertions, 279 deletions

diff --git a/src/main/java/gregtech/api/multitileentity/MultiTileEntityBlock.java b/src/main/java/gregtech/api/multitileentity/MultiTileEntityBlock.java
index 876fa50f0b..dc9a9fd529 100644
--- a/src/main/java/gregtech/api/multitileentity/MultiTileEntityBlock.java
+++ b/src/main/java/gregtech/api/multitileentity/MultiTileEntityBlock.java
@@ -1,5 +1,6 @@
 package gregtech.api.multitileentity;
 
+import static gregtech.api.enums.GT_Values.ALL_VALID_SIDES;
 import static gregtech.api.enums.GT_Values.OFFX;
 import static gregtech.api.enums.GT_Values.OFFY;
 import static gregtech.api.enums.GT_Values.OFFZ;
@@ -20,7 +21,6 @@ import gregtech.api.interfaces.ITexture;
 import gregtech.api.interfaces.tileentity.IDebugableTileEntity;
 import gregtech.api.metatileentity.BaseTileEntity;
 import gregtech.api.metatileentity.CoverableTileEntity;
-import gregtech.api.metatileentity.GregTechTileClientEvents;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity.IMTE_BreakBlock;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity.IMTE_GetBlockHardness;
@@ -35,6 +35,7 @@ import gregtech.api.objects.XSTR;
 import gregtech.api.util.GT_Log;
 import gregtech.api.util.GT_Util;
 import gregtech.api.util.GT_Utility;
+import gregtech.common.covers.CoverInfo;
 import gregtech.common.render.GT_Renderer_Block;
 import gregtech.common.render.IRenderedBlock;
 import java.util.ArrayList;
@@ -451,16 +452,13 @@ public class MultiTileEntityBlock extends Block
             final byte aSide = (byte) side;
             final CoverableTileEntity tile = (CoverableTileEntity) tTileEntity;
             if (side != -1) {
-                final Block facadeBlock = tile.getCoverBehaviorAtSideNew(aSide)
-                        .getFacadeBlock(
-                                aSide, tile.getCoverIDAtSide(aSide), tile.getComplexCoverDataAtSide(aSide), tile);
+                final Block facadeBlock = tile.getCoverInfoAtSide(aSide).getFacadeBlock();
                 if (facadeBlock != null) return facadeBlock;
             } else {
                 // we do not allow more than one type of facade per block, so no need to check every side
                 // see comment in gregtech.common.covers.GT_Cover_FacadeBase.isCoverPlaceable
-                for (byte i = 0; i < 6; i++) {
-                    final Block facadeBlock = tile.getCoverBehaviorAtSideNew(i)
-                            .getFacadeBlock(i, tile.getCoverIDAtSide(i), tile.getComplexCoverDataAtSide(i), tile);
+                for (byte tSide : ALL_VALID_SIDES) {
+                    final Block facadeBlock = tile.getCoverInfoAtSide(tSide).getFacadeBlock();
                     if (facadeBlock != null) {
                         return facadeBlock;
                     }
@@ -477,22 +475,17 @@ public class MultiTileEntityBlock extends Block
             final byte aSide = (byte) side;
             final CoverableTileEntity tile = (CoverableTileEntity) tTileEntity;
             if (side != -1) {
-                final Block facadeBlock = tile.getCoverBehaviorAtSideNew(aSide)
-                        .getFacadeBlock(
-                                aSide, tile.getCoverIDAtSide(aSide), tile.getComplexCoverDataAtSide(aSide), tile);
-                if (facadeBlock != null)
-                    return tile.getCoverBehaviorAtSideNew(aSide)
-                            .getFacadeMeta(
-                                    aSide, tile.getCoverIDAtSide(aSide), tile.getComplexCoverDataAtSide(aSide), tile);
+                final CoverInfo coverInfo = tile.getCoverInfoAtSide(aSide);
+                final Block facadeBlock = coverInfo.getFacadeBlock();
+                if (facadeBlock != null) return coverInfo.getFacadeMeta();
             } else {
                 // we do not allow more than one type of facade per block, so no need to check every side
                 // see comment in gregtech.common.covers.GT_Cover_FacadeBase.isCoverPlaceable
-                for (byte i = 0; i < 6; i++) {
-                    final Block facadeBlock = tile.getCoverBehaviorAtSideNew(i)
-                            .getFacadeBlock(i, tile.getCoverIDAtSide(i), tile.getComplexCoverDataAtSide(i), tile);
+                for (byte tSide : ALL_VALID_SIDES) {
+                    final CoverInfo coverInfo = tile.getCoverInfoAtSide(tSide);
+                    final Block facadeBlock = coverInfo.getFacadeBlock();
                     if (facadeBlock != null) {
-                        return tile.getCoverBehaviorAtSideNew(i)
-                                .getFacadeMeta(i, tile.getCoverIDAtSide(i), tile.getComplexCoverDataAtSide(i), tile);
+                        return coverInfo.getFacadeMeta();
                     }
                 }
             }
@@ -671,59 +664,47 @@ public class MultiTileEntityBlock extends Block
         return aTileEntity instanceof IMultiTileEntity ? ((IMultiTileEntity) aTileEntity).getPickBlock(aTarget) : null;
     }
 
-    public final void receiveMultiTileEntityData(
-            IBlockAccess aWorld,
-            int aX,
-            short aY,
-            int aZ,
-            short aRID,
-            short aID,
-            int aCover0,
-            int aCover1,
-            int aCover2,
-            int aCover3,
-            int aCover4,
-            int aCover5,
-            byte aTextureData,
-            byte aTexturePage,
-            byte aUpdateData,
-            byte aRedstoneData,
-            byte aColorData) {
-        if (!(aWorld instanceof World)) return;
-        final IMultiTileEntity te;
-
+    public final IMultiTileEntity receiveMultiTileEntityData(
+            IBlockAccess aWorld, int aX, short aY, int aZ, short aRID, short aID) {
+        if (!(aWorld instanceof World)) return null;
         TileEntity aTileEntity = aWorld.getTileEntity(aX, aY, aZ);
 
         if (!(aTileEntity instanceof IMultiTileEntity)
                 || ((IMultiTileEntity) aTileEntity).getMultiTileEntityRegistryID() != aRID
                 || ((IMultiTileEntity) aTileEntity).getMultiTileEntityID() != aID) {
             final MultiTileEntityRegistry tRegistry = MultiTileEntityRegistry.getRegistry(aRID);
-            if (tRegistry == null) return;
+            if (tRegistry == null) return null;
 
             aTileEntity = tRegistry.getNewTileEntity((World) aWorld, aX, aY, aZ, aID);
-            if (!(aTileEntity instanceof IMultiTileEntity)) return;
+            if (!(aTileEntity instanceof IMultiTileEntity)) return null;
+
             setTileEntity((World) aWorld, aX, aY, aZ, aTileEntity, false);
         }
-        te = (IMultiTileEntity) aTileEntity;
+        return ((IMultiTileEntity) aTileEntity);
+    }
 
+    public void receiveCoverData(
+            IMultiTileEntity mte, int aCover0, int aCover1, int aCover2, int aCover3, int aCover4, int aCover5) {
         boolean updated;
-        updated = te.setCoverIDAtSideNoUpdate((byte) 0, aCover0);
-        updated |= te.setCoverIDAtSideNoUpdate((byte) 1, aCover1);
-        updated |= te.setCoverIDAtSideNoUpdate((byte) 2, aCover2);
-        updated |= te.setCoverIDAtSideNoUpdate((byte) 3, aCover3);
-        updated |= te.setCoverIDAtSideNoUpdate((byte) 4, aCover4);
-        updated |= te.setCoverIDAtSideNoUpdate((byte) 5, aCover5);
+        updated = mte.setCoverIDAtSideNoUpdate((byte) 0, aCover0);
+        updated |= mte.setCoverIDAtSideNoUpdate((byte) 1, aCover1);
+        updated |= mte.setCoverIDAtSideNoUpdate((byte) 2, aCover2);
+        updated |= mte.setCoverIDAtSideNoUpdate((byte) 3, aCover3);
+        updated |= mte.setCoverIDAtSideNoUpdate((byte) 4, aCover4);
+        updated |= mte.setCoverIDAtSideNoUpdate((byte) 5, aCover5);
 
         if (updated) {
-            te.issueBlockUpdate();
+            mte.issueBlockUpdate();
         }
-
-        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_COMMON_DATA, aTextureData);
-        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_CUSTOM_DATA, aUpdateData & 0x7F);
-        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_CUSTOM_DATA, aTexturePage | 0x80);
-        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_COLOR, aColorData);
-        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_REDSTONE_OUTPUT, aRedstoneData);
     }
+    //
+    //        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_COMMON_DATA, aTextureData);
+    //
+    //        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_CUSTOM_DATA, aUpdateData & 0x7F);
+    //        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_CUSTOM_DATA, aTexturePage | 0x80);
+    //
+    //        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_COLOR, aColorData);
+    //        te.receiveClientEvent(GregTechTileClientEvents.CHANGE_REDSTONE_OUTPUT, aRedstoneData);
 
     @Override
     public final TileEntity createTileEntity(World aWorld, int aMeta) {
diff --git a/src/main/java/gregtech/api/multitileentity/base/BaseMultiTileEntity.java b/src/main/java/gregtech/api/multitileentity/base/BaseMultiTileEntity.java
index 8161680b1e..2ab1f8c7d6 100644
--- a/src/main/java/gregtech/api/multitileentity/base/BaseMultiTileEntity.java
+++ b/src/main/java/gregtech/api/multitileentity/base/BaseMultiTileEntity.java
@@ -15,6 +15,7 @@ import gregtech.api.enums.GT_Values;
 import gregtech.api.enums.Materials;
 import gregtech.api.enums.SoundResource;
 import gregtech.api.enums.Textures;
+import gregtech.api.gui.modularui.GT_UIInfos;
 import gregtech.api.interfaces.IIconContainer;
 import gregtech.api.interfaces.ITexture;
 import gregtech.api.interfaces.tileentity.IGregtechWailaProvider;
@@ -24,9 +25,10 @@ import gregtech.api.metatileentity.GregTechTileClientEvents;
 import gregtech.api.multitileentity.MultiTileEntityBlockInternal;
 import gregtech.api.multitileentity.MultiTileEntityClassContainer;
 import gregtech.api.multitileentity.MultiTileEntityRegistry;
+import gregtech.api.multitileentity.interfaces.IMultiBlockPart;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity;
+import gregtech.api.net.GT_Packet_MultiTileEntity;
 import gregtech.api.net.GT_Packet_New;
-import gregtech.api.net.GT_Packet_TileEntity;
 import gregtech.api.objects.GT_ItemStack;
 import gregtech.api.objects.XSTR;
 import gregtech.api.render.TextureFactory;
@@ -34,7 +36,6 @@ import gregtech.api.util.GT_Log;
 import gregtech.api.util.GT_ModHandler;
 import gregtech.api.util.GT_Util;
 import gregtech.api.util.GT_Utility;
-import gregtech.api.util.ISerializableObject;
 import gregtech.common.render.GT_MultiTexture;
 import gregtech.common.render.IRenderedBlock;
 import java.util.ArrayList;
@@ -55,6 +56,7 @@ import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.network.Packet;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.AxisAlignedBB;
+import net.minecraft.util.ChunkCoordinates;
 import net.minecraft.util.EnumChatFormatting;
 import net.minecraft.util.MovingObjectPosition;
 import net.minecraft.world.Explosion;
@@ -78,9 +80,10 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
     public Materials mMaterial = Materials._NULL;
     protected final boolean mIsTicking; // If this TileEntity is ticking at all
 
-    protected boolean mShouldRefresh =
-            true; // This Variable checks if this TileEntity should refresh when the Block is being set. That way you
+    // This Variable checks if this TileEntity should refresh when the Block is being set. That way you
     // can turn this check off any time you need it.
+    protected boolean mShouldRefresh = true;
+
     protected boolean mDoesBlockUpdate = false; // This Variable is for a buffered Block Update.
     protected boolean mForceFullSelectionBoxes = false; // This Variable is for forcing the Selection Box to be full.
     protected boolean mNeedsUpdate = false;
@@ -192,8 +195,6 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
                 copyTextures();
             }
 
-            if (mCoverData == null || mCoverData.length != 6) mCoverData = new ISerializableObject[6];
-            if (mCoverSides.length != 6) mCoverSides = new int[] {0, 0, 0, 0, 0, 0};
             if (mSidedRedstone.length != 6) mSidedRedstone = new byte[] {15, 15, 15, 15, 15, 15};
 
             updateCoverBehavior();
@@ -252,7 +253,7 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
 
     @Override
     public boolean useModularUI() {
-        return true;
+        return false;
     }
 
     @Override
@@ -730,6 +731,7 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
         try {
             return allowRightclick(aPlayer) && onRightClick(aPlayer, aSide, aX, aY, aZ);
         } catch (Throwable e) {
+            GT_FML_LOGGER.error("onBlockActivated Failed", e);
             e.printStackTrace(GT_Log.err);
             return true;
         }
@@ -747,9 +749,7 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
                 return true;
             }
 
-            if (!getCoverBehaviorAtSideNew(aSide)
-                    .isGUIClickable(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this))
-                return false;
+            if (!getCoverInfoAtSide(aSide).isGUIClickable()) return false;
         }
         if (isServerSide()) {
             if (!privateAccess() || aPlayer.getDisplayName().equalsIgnoreCase(getOwnerName())) {
@@ -826,14 +826,29 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
                                 aY,
                                 aZ)) return true;
 
-                if (!getCoverBehaviorAtSideNew(aSide)
-                        .isGUIClickable(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this))
-                    return false;
+                if (!getCoverInfoAtSide(aSide).isGUIClickable()) return false;
+
+                return openModularUi(aPlayer, aSide);
             }
         }
         return false;
     }
 
+    public boolean hasGui(byte aSide) {
+        return false;
+    }
+
+    boolean openModularUi(EntityPlayer aPlayer, byte aSide) {
+        if (!hasGui(aSide) || !isServerSide()) {
+            System.out.println("No GUI or Not Serverside");
+            return false;
+        }
+
+        GT_UIInfos.openGTTileEntityUI(this, aPlayer);
+        System.out.println("Trying to open a UI");
+        return true;
+    }
+
     public boolean onWrenchRightClick(
             EntityPlayer aPlayer, ItemStack tCurrentItem, byte wrenchSide, float aX, float aY, float aZ) {
         if (setMainFacing(wrenchSide)) {
@@ -955,56 +970,49 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
         return mLockUpgrade;
     }
 
-    public byte getTextureData() {
-        return 0;
-    }
-
     /**
      * @return a Packet containing all Data which has to be synchronised to the Client - Override as needed
      */
     public GT_Packet_New getClientDataPacket() {
-        return new GT_Packet_TileEntity(
+
+        final GT_Packet_MultiTileEntity packet = new GT_Packet_MultiTileEntity(
+                0,
                 xCoord,
                 (short) yCoord,
                 zCoord,
                 getMultiTileEntityRegistryID(),
                 getMultiTileEntityID(),
-                mCoverSides[0],
-                mCoverSides[1],
-                mCoverSides[2],
-                mCoverSides[3],
-                mCoverSides[4],
-                mCoverSides[5],
                 (byte) ((mFacing & 7) | (mRedstone ? 16 : 0)),
-                (byte) getTextureData(), /*getTexturePage()*/
-                (byte) 0, /*getUpdateData()*/
-                (byte) (((mSidedRedstone[0] > 0) ? 1 : 0)
-                        | ((mSidedRedstone[1] > 0) ? 2 : 0)
-                        | ((mSidedRedstone[2] > 0) ? 4 : 0)
-                        | ((mSidedRedstone[3] > 0) ? 8 : 0)
-                        | ((mSidedRedstone[4] > 0) ? 16 : 0)
-                        | ((mSidedRedstone[5] > 0) ? 32 : 0)),
                 mColor);
-    }
-
-    @Override
-    public Packet getDescriptionPacket() {
-        issueClientUpdate();
-        return null;
-    }
 
-    @Override
-    public void getWailaBody(
-            ItemStack itemStack, List<String> currenttip, IWailaDataAccessor accessor, IWailaConfigHandler config) {
-        super.getWailaBody(itemStack, currenttip, accessor, config);
-        currenttip.add(String.format(
-                "Facing: %s", ForgeDirection.getOrientation(getFrontFacing()).name()));
-    }
+        packet.setCoverData(
+                getCoverInfoAtSide((byte) 0).getCoverID(),
+                getCoverInfoAtSide((byte) 1).getCoverID(),
+                getCoverInfoAtSide((byte) 2).getCoverID(),
+                getCoverInfoAtSide((byte) 3).getCoverID(),
+                getCoverInfoAtSide((byte) 4).getCoverID(),
+                getCoverInfoAtSide((byte) 5).getCoverID());
+
+        packet.setRedstoneData((byte) (((mSidedRedstone[0] > 0) ? 1 : 0)
+                | ((mSidedRedstone[1] > 0) ? 2 : 0)
+                | ((mSidedRedstone[2] > 0) ? 4 : 0)
+                | ((mSidedRedstone[3] > 0) ? 8 : 0)
+                | ((mSidedRedstone[4] > 0) ? 16 : 0)
+                | ((mSidedRedstone[5] > 0) ? 32 : 0)));
+
+        if (this instanceof IMTE_HasModes) {
+            final IMTE_HasModes mteModes = (IMTE_HasModes) this;
+            packet.setModes(mteModes.getMode(), mteModes.getAllowedModes());
+        }
+        if (this instanceof IMultiBlockPart) {
+            final IMultiBlockPart mtePart = (IMultiBlockPart) this;
+            if (mtePart.getTargetPos() != null) {
+                final ChunkCoordinates aTarget = mtePart.getTargetPos();
+                packet.setTargetPos(aTarget.posX, (short) aTarget.posY, aTarget.posZ);
+            }
+        }
 
-    @Override
-    public void getWailaNBTData(
-            EntityPlayerMP player, TileEntity tile, NBTTagCompound tag, World world, int x, int y, int z) {
-        super.getWailaNBTData(player, tile, tag, world, x, y, z);
+        return packet;
     }
 
     @Override
@@ -1019,10 +1027,6 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
         sendCoverDataIfNeeded();
     }
 
-    public void setTextureData(byte aValue) {
-        /*Do nothing*/
-    }
-
     @Override
     public boolean receiveClientEvent(int aEventID, int aValue) {
         super.receiveClientEvent(aEventID, aValue);
@@ -1037,10 +1041,7 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
                     // mWorks =  ((aValue & 64) != 0);
                     break;
                 case GregTechTileClientEvents.CHANGE_CUSTOM_DATA:
-                    if ((aValue & 0x80) != 0) // Is texture index
-                    setTextureData((byte) (aValue & 0x7F));
-                    // else if (mMetaTileEntity instanceof GT_MetaTileEntity_Hatch)//is texture page and hatch
-                    //    ((GT_MetaTileEntity_Hatch) mMetaTileEntity).onTexturePageUpdate((byte) (aValue & 0x7F));
+                    // Nothing here, currently
                     break;
                 case GregTechTileClientEvents.CHANGE_COLOR:
                     if (aValue > 16 || aValue < 0) aValue = 0;
@@ -1075,6 +1076,26 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
     }
 
     @Override
+    public Packet getDescriptionPacket() {
+        issueClientUpdate();
+        return null;
+    }
+
+    @Override
+    public void getWailaBody(
+            ItemStack itemStack, List<String> currenttip, IWailaDataAccessor accessor, IWailaConfigHandler config) {
+        super.getWailaBody(itemStack, currenttip, accessor, config);
+        currenttip.add(String.format(
+                "Facing: %s", ForgeDirection.getOrientation(getFrontFacing()).name()));
+    }
+
+    @Override
+    public void getWailaNBTData(
+            EntityPlayerMP player, TileEntity tile, NBTTagCompound tag, World world, int x, int y, int z) {
+        super.getWailaNBTData(player, tile, tag, world, x, y, z);
+    }
+
+    @Override
     public boolean hasCustomInventoryName() {
         return false;
     }
@@ -1262,11 +1283,13 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
      */
     @Override
     public void openInventory() {
+        System.out.println("Open Inventory");
         /* Do nothing */
     }
 
     @Override
     public void closeInventory() {
+        System.out.println("Close Inventory");
         /* Do nothing */
     }
 
@@ -1350,33 +1373,27 @@ public abstract class BaseMultiTileEntity extends CoverableTileEntity
      */
 
     public boolean coverLetsFluidIn(byte aSide, Fluid aFluid) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsFluidIn(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), aFluid, this);
+        return getCoverInfoAtSide(aSide).letsFluidIn(aFluid);
     }
 
     public boolean coverLetsFluidOut(byte aSide, Fluid aFluid) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsFluidOut(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), aFluid, this);
+        return getCoverInfoAtSide(aSide).letsFluidOut(aFluid);
     }
 
     public boolean coverLetsEnergyIn(byte aSide) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsEnergyIn(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this);
+        return getCoverInfoAtSide(aSide).letsEnergyIn();
     }
 
     public boolean coverLetsEnergyOut(byte aSide) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsEnergyOut(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this);
+        return getCoverInfoAtSide(aSide).letsEnergyOut();
     }
 
     public boolean coverLetsItemsIn(byte aSide, int aSlot) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsItemsIn(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), aSlot, this);
+        return getCoverInfoAtSide(aSide).letsItemsIn(aSlot);
     }
 
     public boolean coverLetsItemsOut(byte aSide, int aSlot) {
-        return getCoverBehaviorAtSideNew(aSide)
-                .letsItemsOut(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), aSlot, this);
+        return getCoverInfoAtSide(aSide).letsItemsOut(aSlot);
     }
 
     @Override
diff --git a/src/main/java/gregtech/api/multitileentity/base/BaseNontickableMultiTileEntity.java b/src/main/java/gregtech/api/multitileentity/base/BaseNontickableMultiTileEntity.java
index bc6f2439ea..9b3deb9d69 100644
--- a/src/main/java/gregtech/api/multitileentity/base/BaseNontickableMultiTileEntity.java
+++ b/src/main/java/gregtech/api/multitileentity/base/BaseNontickableMultiTileEntity.java
@@ -4,6 +4,7 @@ import static gregtech.api.enums.GT_Values.NW;
 
 import gregtech.api.net.GT_Packet_SendCoverData;
 import gregtech.api.util.ISerializableObject;
+import gregtech.common.covers.CoverInfo;
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.network.Packet;
 
@@ -37,13 +38,11 @@ public abstract class BaseNontickableMultiTileEntity extends BaseMultiTileEntity
             super.issueCoverUpdate(aSide);
         } else {
             // Otherwise, send the data right away
-            NW.sendPacketToAllPlayersInRange(
-                    worldObj,
-                    new GT_Packet_SendCoverData(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this),
-                    xCoord,
-                    zCoord);
+            final CoverInfo coverInfo = getCoverInfoAtSide(aSide);
+            NW.sendPacketToAllPlayersInRange(worldObj, new GT_Packet_SendCoverData(coverInfo, this), xCoord, zCoord);
+
             // Just in case
-            mCoverNeedUpdate[aSide] = false;
+            coverInfo.setNeedsUpdate(false);
         }
     }
 
diff --git a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockController.java b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockController.java
index 74d1252eeb..414ba24948 100644
--- a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockController.java
+++ b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockController.java
@@ -18,4 +18,8 @@ public interface IMultiBlockController
     boolean isLiquidInput(byte aSide);
 
     boolean isLiquidOutput(byte aSide);
+
+    void registerCoveredPartOnSide(final int aSide, IMultiBlockPart part);
+
+    void unregisterCoveredPartOnSide(final int aSide, IMultiBlockPart part);
 }
diff --git a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockFluidHandler.java b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockFluidHandler.java
index e5d2e4f691..528c153e05 100644
--- a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockFluidHandler.java
+++ b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockFluidHandler.java
@@ -5,6 +5,7 @@ import net.minecraftforge.common.util.ForgeDirection;
 import net.minecraftforge.fluids.Fluid;
 import net.minecraftforge.fluids.FluidStack;
 import net.minecraftforge.fluids.FluidTankInfo;
+import net.minecraftforge.fluids.IFluidTank;
 
 public interface IMultiBlockFluidHandler {
     int fill(MultiBlockPart aPart, ForgeDirection aDirection, FluidStack aFluid, boolean aDoFill);
@@ -18,4 +19,6 @@ public interface IMultiBlockFluidHandler {
     boolean canDrain(MultiBlockPart aPart, ForgeDirection aDirection, Fluid aFluid);
 
     FluidTankInfo[] getTankInfo(MultiBlockPart aPart, ForgeDirection aDirection);
+
+    IFluidTank[] getFluidTanksForGUI(MultiBlockPart aPart);
 }
diff --git a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockInventory.java b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockInventory.java
index 7e3777fe90..c50addbe67 100644
--- a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockInventory.java
+++ b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockInventory.java
@@ -1,6 +1,8 @@
 package gregtech.api.multitileentity.interfaces;
 
+import com.gtnewhorizons.modularui.api.forge.IItemHandlerModifiable;
 import gregtech.api.multitileentity.multiblock.base.MultiBlockPart;
+import java.util.List;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
 
@@ -44,4 +46,8 @@ public interface IMultiBlockInventory {
     void closeInventory(MultiBlockPart aPart);
 
     boolean isItemValidForSlot(MultiBlockPart aPart, int aSlot, ItemStack aStack);
+
+    IItemHandlerModifiable getInventoryForGUI(MultiBlockPart aPart);
+
+    List<String> getInventoryNames(MultiBlockPart aPart);
 }
diff --git a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockPart.java b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockPart.java
new file mode 100644
index 0000000000..027b49ca17
--- /dev/null
+++ b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiBlockPart.java
@@ -0,0 +1,11 @@
+package gregtech.api.multitileentity.interfaces;
+
+import net.minecraft.util.ChunkCoordinates;
+
+public interface IMultiBlockPart extends IMultiTileEntity {
+    ChunkCoordinates getTargetPos();
+
+    void setTargetPos(ChunkCoordinates aTargetPos);
+
+    boolean tickCoverAtSide(byte aSide, long aTickTimer);
+}
diff --git a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiTileEntity.java b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiTileEntity.java
index f5278d47b4..8b900ad61c 100644
--- a/src/main/java/gregtech/api/multitileentity/interfaces/IMultiTileEntity.java
+++ b/src/main/java/gregtech/api/multitileentity/interfaces/IMultiTileEntity.java
@@ -287,4 +287,14 @@ public interface IMultiTileEntity
         /** Adds ToolTips to the Item. */
         void addToolTips(List<String> aList, ItemStack aStack, boolean aF3_H);
     }
+
+    interface IMTE_HasModes extends IMultiTileEntity {
+        byte getMode();
+
+        void setMode(byte aMode);
+
+        int getAllowedModes();
+
+        void setAllowedModes(int aAllowedModes);
+    }
 }
diff --git a/src/main/java/gregtech/api/multitileentity/machine/MultiTileBasicMachine.java b/src/main/java/gregtech/api/multitileentity/machine/MultiTileBasicMachine.java
index 767026b286..17bf44c386 100644
--- a/src/main/java/gregtech/api/multitileentity/machine/MultiTileBasicMachine.java
+++ b/src/main/java/gregtech/api/multitileentity/machine/MultiTileBasicMachine.java
@@ -3,6 +3,8 @@ package gregtech.api.multitileentity.machine;
 import static com.google.common.primitives.Ints.saturatedCast;
 import static gregtech.api.enums.GT_Values.emptyIconContainerArray;
 
+import com.gtnewhorizons.modularui.api.forge.IItemHandlerModifiable;
+import com.gtnewhorizons.modularui.api.forge.ItemStackHandler;
 import gregtech.api.enums.GT_Values;
 import gregtech.api.enums.GT_Values.NBT;
 import gregtech.api.enums.Textures;
@@ -32,10 +34,11 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
     protected boolean mActive = false;
     protected long mStoredEnergy = 0;
     protected FluidTankGT[] mTanksInput = GT_Values.emptyFluidTankGT, mTanksOutput = GT_Values.emptyFluidTankGT;
-    protected ItemStack[] mOutputItems = GT_Values.emptyItemStackArray;
     protected FluidStack[] mOutputFluids = GT_Values.emptyFluidStack;
 
-    protected ItemStack[] mInventory = GT_Values.emptyItemStackArray;
+    protected final IItemHandlerModifiable mInputInventory = new ItemStackHandler(17);
+    protected final IItemHandlerModifiable mOutputInventory = new ItemStackHandler(15);
+    protected boolean mOutputInventoryChanged = false;
 
     @Override
     public String getTileEntityName() {
@@ -47,6 +50,43 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
         super.writeMultiTileNBT(aNBT);
         if (mParallel > 0) aNBT.setInteger(NBT.PARALLEL, mParallel);
         if (mActive) aNBT.setBoolean(NBT.ACTIVE, mActive);
+        if (mInputInventory != null && mInputInventory.getSlots() > 0)
+            writeInventory(aNBT, mInputInventory, NBT.INV_INPUT_LIST);
+        if (mOutputInventory != null && mOutputInventory.getSlots() > 0)
+            writeInventory(aNBT, mOutputInventory, NBT.INV_OUTPUT_LIST);
+        for (int i = 0; i < mTanksInput.length; i++) mTanksInput[i].writeToNBT(aNBT, NBT.TANK_IN + i);
+        for (int i = 0; i < mTanksOutput.length; i++) mTanksOutput[i].writeToNBT(aNBT, NBT.TANK_OUT + i);
+        if (mOutputFluids != null && mOutputFluids.length > 0) writeFluids(aNBT, mOutputFluids, NBT.FLUID_OUT);
+    }
+
+    protected void writeFluids(NBTTagCompound aNBT, FluidStack[] fluids, String fluidListTag) {
+        if (fluids != null && fluids.length > 0) {
+            final NBTTagList tList = new NBTTagList();
+            for (final FluidStack tFluid : fluids) {
+                if (tFluid != null) {
+                    final NBTTagCompound tag = new NBTTagCompound();
+                    tFluid.writeToNBT(tag);
+                    tList.appendTag(tag);
+                }
+            }
+            aNBT.setTag(fluidListTag, tList);
+        }
+    }
+
+    protected void writeInventory(NBTTagCompound aNBT, IItemHandlerModifiable inv, String invListTag) {
+        if (inv != null && inv.getSlots() > 0) {
+            final NBTTagList tList = new NBTTagList();
+            for (int tSlot = 0; tSlot < inv.getSlots(); tSlot++) {
+                final ItemStack tStack = inv.getStackInSlot(tSlot);
+                if (tStack != null) {
+                    final NBTTagCompound tag = new NBTTagCompound();
+                    tag.setByte("s", (byte) tSlot);
+                    tStack.writeToNBT(tag);
+                    tList.appendTag(tag);
+                }
+            }
+            aNBT.setTag(invListTag, tList);
+        }
     }
 
     @Override
@@ -55,15 +95,10 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
         if (aNBT.hasKey(NBT.PARALLEL)) mParallel = Math.max(1, aNBT.getInteger(NBT.PARALLEL));
         if (aNBT.hasKey(NBT.ACTIVE)) mActive = aNBT.getBoolean(NBT.ACTIVE);
 
-        mInventory = getDefaultInventory(aNBT);
-        if (mInventory != null) {
-            final NBTTagList tList = aNBT.getTagList(NBT.INV_LIST, 10);
-            for (int i = 0; i < tList.tagCount(); i++) {
-                final NBTTagCompound tNBT = tList.getCompoundTagAt(i);
-                final int tSlot = tNBT.getShort("s");
-                if (tSlot >= 0 && tSlot < mInventory.length) mInventory[tSlot] = GT_Utility.loadItem(tNBT);
-            }
-        }
+        /* Inventories */
+        loadInventory(aNBT, NBT.INV_INPUT_SIZE, NBT.INV_INPUT_LIST);
+        loadInventory(aNBT, NBT.INV_OUTPUT_SIZE, NBT.INV_OUTPUT_LIST);
+
         /* Tanks */
         long tCapacity = 1000;
         if (aNBT.hasKey(NBT.TANK_CAPACITY)) tCapacity = saturatedCast(aNBT.getLong(NBT.TANK_CAPACITY));
@@ -71,7 +106,6 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
         mTanksInput = new FluidTankGT[getFluidInputCount()];
         mTanksOutput = new FluidTankGT[getFluidOutputCount()];
         mOutputFluids = new FluidStack[getFluidOutputCount()];
-        mOutputItems = new ItemStack[getItemOutputCount()];
 
         // TODO: See if we need the adjustable map here `.setCapacity(mRecipes, mParallel * 2L)` in place of the
         // `setCapacityMultiplier`
@@ -83,8 +117,18 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
             mTanksOutput[i] = new FluidTankGT().readFromNBT(aNBT, NBT.TANK_OUT + i);
         for (int i = 0; i < mOutputFluids.length; i++)
             mOutputFluids[i] = FluidStack.loadFluidStackFromNBT(aNBT.getCompoundTag(NBT.FLUID_OUT + "." + i));
-        for (int i = 0; i < mOutputItems.length; i++)
-            mOutputItems[i] = ItemStack.loadItemStackFromNBT(aNBT.getCompoundTag(NBT.INV_OUT + "." + i));
+    }
+
+    protected void loadInventory(NBTTagCompound aNBT, String sizeTag, String invListTag) {
+        final IItemHandlerModifiable inv = mInputInventory;
+        if (inv != null) {
+            final NBTTagList tList = aNBT.getTagList(invListTag, 10);
+            for (int i = 0; i < tList.tagCount(); i++) {
+                final NBTTagCompound tNBT = tList.getCompoundTagAt(i);
+                final int tSlot = tNBT.getShort("s");
+                if (tSlot >= 0 && tSlot < inv.getSlots()) inv.setStackInSlot(tSlot, GT_Utility.loadItem(tNBT));
+            }
+        }
     }
 
     @Override
@@ -148,19 +192,14 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
      * The number of fluid (input) slots available for this machine
      */
     public int getFluidInputCount() {
-        return 2;
+        return 7;
     }
 
     /**
      * The number of fluid (output) slots available for this machine
      */
     public int getFluidOutputCount() {
-        return 2;
-    }
-
-    public ItemStack[] getDefaultInventory(NBTTagCompound aNBT) {
-        final int tSize = Math.max(0, aNBT.getShort(NBT.INV_SIZE));
-        return tSize > 0 ? new ItemStack[tSize] : GT_Values.emptyItemStackArray;
+        return 3;
     }
 
     @Override
@@ -292,8 +331,7 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
         if (aSide == GT_Values.SIDE_UNKNOWN) return true;
         if (aSide >= 0 && aSide < 6) {
             if (isInvalid()) return false;
-            if (!getCoverBehaviorAtSideNew(aSide)
-                    .letsEnergyIn(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this)) return false;
+            if (!getCoverInfoAtSide(aSide).letsEnergyIn()) return false;
             if (isEnetInput()) return isEnergyInputSide(aSide);
         }
         return false;
@@ -304,9 +342,7 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
         if (aSide == GT_Values.SIDE_UNKNOWN) return true;
         if (aSide >= 0 && aSide < 6) {
             if (isInvalid()) return false;
-            if (!getCoverBehaviorAtSideNew(aSide)
-                    .letsEnergyOut(aSide, getCoverIDAtSide(aSide), getComplexCoverDataAtSide(aSide), this))
-                return false;
+            if (!getCoverInfoAtSide(aSide).letsEnergyOut()) return false;
             if (isEnetOutput()) return isEnergyOutputSide(aSide);
         }
         return false;
@@ -318,9 +354,19 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
 
     @Override
     public boolean hasInventoryBeenModified() {
+        // True if the input inventory has changed
         return mInventoryChanged;
     }
 
+    public void markOutputInventoryBeenModified() {
+        mOutputInventoryChanged = true;
+    }
+
+    public boolean hasOutputInventoryBeenModified() {
+        // True if the output inventory has changed
+        return mOutputInventoryChanged;
+    }
+
     @Override
     public boolean isItemValidForSlot(int aSlot, ItemStack aStack) {
         return false;
@@ -330,18 +376,4 @@ public class MultiTileBasicMachine extends BaseTickableMultiTileEntity {
     public int getInventoryStackLimit() {
         return 64;
     }
-
-    /**
-     * The number of item (input) slots available for this machine
-     */
-    public int getItemInputCount() {
-        return 2;
-    }
-
-    /**
-     * The number of item (output) slots available for this machine
-     */
-    public int getItemOutputCount() {
-        return 2;
-    }
 }
diff --git a/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockController.java b/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockController.java
index bb01f0b4fa..49f2adcd40 100644
--- a/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockController.java
+++ b/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockController.java
@@ -1,6 +1,7 @@
 package gregtech.api.multitileentity.multiblock.base;
 
 import static gregtech.GT_Mod.GT_FML_LOGGER;
+import static gregtech.api.enums.GT_Values.ALL_VALID_SIDES;
 import static gregtech.api.enums.GT_Values.NBT;
 
 import com.gtnewhorizon.structurelib.StructureLibAPI;
@@ -13,12 +14,26 @@ import com.gtnewhorizon.structurelib.alignment.enumerable.Rotation;
 import com.gtnewhorizon.structurelib.structure.IStructureDefinition;
 import com.gtnewhorizon.structurelib.structure.IStructureElement;
 import com.gtnewhorizon.structurelib.util.Vec3Impl;
+import com.gtnewhorizons.modularui.api.ModularUITextures;
+import com.gtnewhorizons.modularui.api.drawable.ItemDrawable;
+import com.gtnewhorizons.modularui.api.forge.IItemHandlerModifiable;
+import com.gtnewhorizons.modularui.api.forge.ListItemHandler;
+import com.gtnewhorizons.modularui.api.screen.*;
+import com.gtnewhorizons.modularui.api.widget.Widget;
+import com.gtnewhorizons.modularui.common.widget.DrawableWidget;
+import com.gtnewhorizons.modularui.common.widget.FluidSlotWidget;
+import com.gtnewhorizons.modularui.common.widget.MultiChildWidget;
+import com.gtnewhorizons.modularui.common.widget.Scrollable;
+import com.gtnewhorizons.modularui.common.widget.SlotWidget;
+import com.gtnewhorizons.modularui.common.widget.TabButton;
+import com.gtnewhorizons.modularui.common.widget.TabContainer;
 import cpw.mods.fml.common.network.NetworkRegistry;
 import gnu.trove.list.TIntList;
 import gnu.trove.list.array.TIntArrayList;
 import gregtech.api.enums.GT_Values;
 import gregtech.api.enums.OrePrefixes;
 import gregtech.api.enums.TextureSet;
+import gregtech.api.gui.modularui.GT_UITextures;
 import gregtech.api.interfaces.IDescribable;
 import gregtech.api.interfaces.tileentity.IMachineProgress;
 import gregtech.api.multitileentity.MultiTileEntityContainer;
@@ -26,14 +41,19 @@ import gregtech.api.multitileentity.MultiTileEntityRegistry;
 import gregtech.api.multitileentity.interfaces.IMultiBlockController;
 import gregtech.api.multitileentity.interfaces.IMultiBlockFluidHandler;
 import gregtech.api.multitileentity.interfaces.IMultiBlockInventory;
+import gregtech.api.multitileentity.interfaces.IMultiBlockPart;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity.IMTE_AddToolTips;
 import gregtech.api.multitileentity.machine.MultiTileBasicMachine;
 import gregtech.api.objects.GT_ItemStack;
 import gregtech.api.util.GT_Multiblock_Tooltip_Builder;
 import gregtech.api.util.GT_Utility;
+import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -65,9 +85,8 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
 
     protected BuildState buildState = new BuildState();
 
-    // The 0th slot is the default inventory of the MultiBlock; any other has been added by an Inventory Extender of
-    // sorts
-    protected List<ItemStack[]> multiBlockInventory = new ArrayList<>();
+    protected Map<String, IItemHandlerModifiable> multiBlockInputInventory = new LinkedHashMap<>();
+    protected Map<String, IItemHandlerModifiable> multiBlockOutputInventory = new LinkedHashMap<>();
 
     private int mMaxProgresstime = 0, mProgresstime = 0;
     private boolean mStructureOkay = false, mStructureChanged = false;
@@ -75,6 +94,16 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     private ExtendedFacing mExtendedFacing = ExtendedFacing.DEFAULT;
     private IAlignmentLimits mLimits = getInitialAlignmentLimits();
 
+    // A list of sides
+    //   Each side has a list of parts that have a cover that need to be ticked
+    protected List<LinkedList<WeakReference<IMultiBlockPart>>> registeredCoveredParts = Arrays.asList(
+            new LinkedList<>(),
+            new LinkedList<>(),
+            new LinkedList<>(),
+            new LinkedList<>(),
+            new LinkedList<>(),
+            new LinkedList<>());
+
     /** Registry ID of the required casing */
     public abstract short getCasingRegistryID();
     /** Meta ID of the required casing */
@@ -125,7 +154,8 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
         // Multiblock inventories are a collection of inventories.  The first inventory is the default internal
         // inventory,
         // and the others are added by inventory extending blocks.
-        if (mInventory != null) multiBlockInventory.add(mInventory);
+        if (mInputInventory != null) multiBlockInputInventory.put("controller", mInputInventory);
+        if (mOutputInventory != null) multiBlockOutputInventory.put("controller", mOutputInventory);
 
         mStructureOkay = aNBT.getBoolean(NBT.STRUCTURE_OK);
         mExtendedFacing = ExtendedFacing.of(
@@ -159,12 +189,6 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
 
     protected GT_Multiblock_Tooltip_Builder getTooltip() {
         return createTooltip();
-        //        final int tooltipId = getToolTipID();
-        //        final GT_Multiblock_Tooltip_Builder tt = tooltip.get(tooltipId);
-        //        if (tt == null) {
-        //            return tooltip.computeIfAbsent(tooltipId, k -> createTooltip());
-        //        }
-        //        return tt;
     }
 
     @Override
@@ -277,8 +301,8 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
             return super.onWrenchRightClick(aPlayer, tCurrentItem, wrenchSide, aX, aY, aZ);
         if (aPlayer.isSneaking()) {
             // we won't be allowing horizontal flips, as it can be perfectly emulated by rotating twice and flipping
-            // horizontally
-            // allowing an extra round of flip make it hard to draw meaningful flip markers in GT_Proxy#drawGrid
+            // horizontally allowing an extra round of flip make it hard to draw meaningful flip markers in
+            // GT_Proxy#drawGrid
             toolSetFlip(getFlip().isHorizontallyFlipped() ? Flip.NONE : Flip.HORIZONTAL);
         } else {
             toolSetRotation(null);
@@ -287,12 +311,59 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     }
 
     @Override
+    public void registerCoveredPartOnSide(final int aSide, IMultiBlockPart part) {
+        if (aSide < 0 || aSide >= 6) return;
+
+        final LinkedList<WeakReference<IMultiBlockPart>> registeredCovers = registeredCoveredParts.get(aSide);
+        // TODO: Make sure that we're not already registered on this side
+        registeredCovers.add(new WeakReference<>(part));
+    }
+
+    @Override
+    public void unregisterCoveredPartOnSide(final int aSide, IMultiBlockPart aPart) {
+        if (aSide < 0 || aSide >= 6) return;
+
+        final LinkedList<WeakReference<IMultiBlockPart>> coveredParts = registeredCoveredParts.get(aSide);
+        final Iterator<WeakReference<IMultiBlockPart>> it = coveredParts.iterator();
+        while (it.hasNext()) {
+            final IMultiBlockPart part = (it.next()).get();
+            if (part == null || part == aPart) it.remove();
+        }
+    }
+
+    @Override
     public void onFirstTick(boolean aIsServerSide) {
         super.onFirstTick(aIsServerSide);
         if (aIsServerSide) checkStructure(true);
         else StructureLibAPI.queryAlignment(this);
     }
 
+    private boolean tickCovers() {
+        for (byte side : ALL_VALID_SIDES) {
+            // TODO: Tick controller covers, if any
+            final LinkedList<WeakReference<IMultiBlockPart>> coveredParts = this.registeredCoveredParts.get(side);
+            final Iterator<WeakReference<IMultiBlockPart>> it = coveredParts.iterator();
+            while (it.hasNext()) {
+                final IMultiBlockPart part = (it.next()).get();
+                if (part == null) {
+                    it.remove();
+                    continue;
+                }
+                if (!part.tickCoverAtSide(side, mTickTimer)) it.remove();
+            }
+        }
+
+        return true;
+    }
+
+    @Override
+    public void onTick(long aTimer, boolean isServerSide) {
+        // Tick all covers!
+        if (!tickCovers()) {
+            return;
+        }
+    }
+
     @Override
     public void onPostTick(long aTick, boolean aIsServerSide) {
         if (aIsServerSide) {
@@ -489,7 +560,7 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
                     mIcons = new IIcon[6];
                     Arrays.fill(mIcons, TextureSet.SET_NONE.mTextures[OrePrefixes.block.mTextureIndex].getIcon());
                     //                    Arrays.fill(mIcons, getTexture(aCasing);
-                    //                    for (int i = 0; i < 6; i++) {
+                    //                    for (byte i : ALL_VALID_SIDES) {
                     //                        mIcons[i] = aCasing.getIcon(i, aMeta);
                     //                    }
                 }
@@ -598,6 +669,13 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
         return rInfo;
     }
 
+    @Override
+    public IFluidTank[] getFluidTanksForGUI(MultiBlockPart aPart) {
+        if (aPart.modeSelected(MultiBlockPart.FLUID_IN)) return mTanksInput;
+        if (aPart.modeSelected(MultiBlockPart.FLUID_OUT)) return mTanksOutput;
+        return GT_Values.emptyFluidTank;
+    }
+
     /**
      * Energy - MultiBlock related Energy behavior
      */
@@ -699,10 +777,18 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     /**
      * Item - MultiBlock related Item behaviour.
      */
+    protected boolean registerInventory(String invName, IItemHandlerModifiable inventory) {
+        if (multiBlockInputInventory.containsKey(invName)) return false;
+        multiBlockInputInventory.put(invName, inventory);
+        return true;
+    }
+
     @Override
     public boolean hasInventoryBeenModified(MultiBlockPart aPart) {
-        // TODO: MultiInventory - Figure this out based on locked & the part
-        return hasInventoryBeenModified();
+        if (aPart.modeSelected(MultiBlockPart.ITEM_IN)) return hasInventoryBeenModified();
+        else if (aPart.modeSelected(MultiBlockPart.ITEM_OUT)) return hasOutputInventoryBeenModified();
+
+        return false;
     }
 
     @Override
@@ -711,6 +797,20 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     }
 
     @Override
+    public IItemHandlerModifiable getInventoryForGUI(MultiBlockPart aPart) {
+        final Map<String, IItemHandlerModifiable> multiBlockInventory = getMultiBlockInventory(aPart);
+        if (multiBlockInventory == null) return null;
+
+        final String lockedInventory = aPart.getLockedInventory();
+        if (lockedInventory == null) {
+            return new ListItemHandler(multiBlockInventory.values());
+        } else {
+            final IItemHandlerModifiable inv = multiBlockInventory.get(lockedInventory);
+            return inv != null ? inv : null;
+        }
+    }
+
+    @Override
     public boolean addStackToSlot(MultiBlockPart aPart, int aIndex, ItemStack aStack) {
         return false;
     }
@@ -720,15 +820,25 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
         return false;
     }
 
-    protected Pair<ItemStack[], Integer> getInventory(int lockedInventory, int aSlot) {
-        if (lockedInventory != -1) return new ImmutablePair<>(multiBlockInventory.get(lockedInventory), aSlot);
+    protected Map<String, IItemHandlerModifiable> getMultiBlockInventory(MultiBlockPart aPart) {
+        if (aPart.modeSelected(MultiBlockPart.ITEM_IN)) return multiBlockInputInventory;
+        else if (aPart.modeSelected(MultiBlockPart.ITEM_OUT)) return multiBlockOutputInventory;
+        return null;
+    }
+
+    protected Pair<IItemHandlerModifiable, Integer> getInventory(MultiBlockPart aPart, int aSlot) {
+        final Map<String, IItemHandlerModifiable> multiBlockInventory = getMultiBlockInventory(aPart);
+        if (multiBlockInventory == null) return null;
+
+        final String invName = aPart.getLockedInventory();
+        if (invName != null && !invName.isEmpty()) return new ImmutablePair<>(multiBlockInventory.get(invName), aSlot);
 
         int start = 0;
-        for (ItemStack[] inv : multiBlockInventory) {
-            if (aSlot > start && aSlot < start + inv.length) {
+        for (IItemHandlerModifiable inv : multiBlockInventory.values()) {
+            if (aSlot >= start && aSlot < start + inv.getSlots()) {
                 return new ImmutablePair<>(inv, aSlot - start);
             }
-            start += inv.length;
+            start += inv.getSlots();
         }
         return null;
     }
@@ -736,16 +846,22 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     @Override
     public int[] getAccessibleSlotsFromSide(MultiBlockPart aPart, byte aSide) {
         final TIntList tList = new TIntArrayList();
-        final int lockedInventory = aPart.getLockedInventory();
+        final Map<String, IItemHandlerModifiable> multiBlockInventory = getMultiBlockInventory(aPart);
+        if (multiBlockInventory == null) return tList.toArray();
+
+        final String lockedInventory = aPart.getLockedInventory();
+        // Item in --> input inv
+        // Item out --> output inv
 
         int start = 0;
-        if (lockedInventory == -1) {
-            for (ItemStack[] inv : multiBlockInventory) {
-                for (int i = start; i < inv.length + start; i++) tList.add(i);
-                start += inv.length;
+        if (lockedInventory == null) {
+            for (IItemHandlerModifiable inv : multiBlockInventory.values()) {
+                for (int i = start; i < inv.getSlots() + start; i++) tList.add(i);
+                start += inv.getSlots();
             }
         } else {
-            final int len = multiBlockInventory.get(lockedInventory).length;
+            final IItemHandlerModifiable inv = multiBlockInventory.get(lockedInventory);
+            final int len = inv != null ? inv.getSlots() : 0;
             for (int i = 0; i < len; i++) tList.add(i);
         }
         return tList.toArray();
@@ -753,64 +869,59 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
 
     @Override
     public boolean canInsertItem(MultiBlockPart aPart, int aSlot, ItemStack aStack, byte aSide) {
-        final int lockedInventory = aPart.getLockedInventory(), tSlot;
-        final ItemStack[] inv;
-        if (lockedInventory == -1) {
-            final Pair<ItemStack[], Integer> tInv = getInventory(lockedInventory, aSlot);
-            if (tInv == null) return false;
-            inv = tInv.getLeft();
-            tSlot = tInv.getRight();
-        } else {
-            inv = multiBlockInventory.get(lockedInventory);
-            tSlot = aSlot;
-        }
-        return inv[tSlot] == null
+        final Pair<IItemHandlerModifiable, Integer> tInv = getInventory(aPart, aSlot);
+        if (tInv == null) return false;
+
+        final int tSlot = tInv.getRight();
+        final IItemHandlerModifiable inv = tInv.getLeft();
+        ;
+
+        return inv.getStackInSlot(tSlot) == null
                 || GT_Utility.areStacksEqual(
-                        aStack, inv[tSlot]); // && allowPutStack(getBaseMetaTileEntity(), aIndex, (byte) aSide, aStack)
+                        aStack,
+                        inv.getStackInSlot(
+                                tSlot)); // && allowPutStack(getBaseMetaTileEntity(), aIndex, (byte) aSide, aStack)
     }
 
     @Override
     public boolean canExtractItem(MultiBlockPart aPart, int aSlot, ItemStack aStack, byte aSide) {
-        final int lockedInventory = aPart.getLockedInventory(), tSlot;
-        final ItemStack[] inv;
-        if (lockedInventory == -1) {
-            final Pair<ItemStack[], Integer> tInv = getInventory(lockedInventory, aSlot);
-            if (tInv == null) return false;
-            inv = tInv.getLeft();
-            tSlot = tInv.getRight();
-        } else {
-            inv = multiBlockInventory.get(lockedInventory);
-            tSlot = aSlot;
-        }
-        return inv[tSlot] != null; // && allowPullStack(getBaseMetaTileEntity(), aIndex, (byte) aSide, aStack);
+        final Pair<IItemHandlerModifiable, Integer> tInv = getInventory(aPart, aSlot);
+        if (tInv == null) return false;
+
+        final int tSlot = tInv.getRight();
+        final IItemHandlerModifiable inv = tInv.getLeft();
+        ;
+
+        return inv.getStackInSlot(tSlot)
+                != null; // && allowPullStack(getBaseMetaTileEntity(), aIndex, (byte) aSide, aStack);
     }
 
     @Override
     public int getSizeInventory(MultiBlockPart aPart) {
-        final int lockedInventory = aPart.getLockedInventory();
-        if (lockedInventory == -1) {
+        final Map<String, IItemHandlerModifiable> multiBlockInventory = getMultiBlockInventory(aPart);
+        if (multiBlockInventory == null) return 0;
+
+        final String lockedInventory = aPart.getLockedInventory();
+        if (lockedInventory == null) {
             int len = 0;
-            for (ItemStack[] inv : multiBlockInventory) len += inv.length;
+            for (IItemHandlerModifiable inv : multiBlockInventory.values()) len += inv.getSlots();
             return len;
         } else {
-            return multiBlockInventory.get(lockedInventory).length;
+            final IItemHandlerModifiable inv = multiBlockInventory.get(lockedInventory);
+            return inv != null ? inv.getSlots() : 0;
         }
     }
 
     @Override
     public ItemStack getStackInSlot(MultiBlockPart aPart, int aSlot) {
-        final int lockedInventory = aPart.getLockedInventory(), tSlot;
-        final ItemStack[] inv;
-        if (lockedInventory == -1) {
-            final Pair<ItemStack[], Integer> tInv = getInventory(lockedInventory, aSlot);
-            if (tInv == null) return null;
-            inv = tInv.getLeft();
-            tSlot = tInv.getRight();
-        } else {
-            inv = multiBlockInventory.get(lockedInventory);
-            tSlot = aSlot;
-        }
-        return inv[tSlot];
+        final Pair<IItemHandlerModifiable, Integer> tInv = getInventory(aPart, aSlot);
+        if (tInv == null) return null;
+
+        final int tSlot = tInv.getRight();
+        final IItemHandlerModifiable inv = tInv.getLeft();
+        if (inv == null) return null;
+
+        return inv.getStackInSlot(tSlot);
     }
 
     @Override
@@ -819,10 +930,10 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
         ItemStack rStack = GT_Utility.copyOrNull(tStack);
         if (tStack != null) {
             if (tStack.stackSize <= aDecrement) {
-                setInventorySlotContents(aSlot, null);
+                setInventorySlotContents(aPart, aSlot, null);
             } else {
                 rStack = tStack.splitStack(aDecrement);
-                if (tStack.stackSize == 0) setInventorySlotContents(aSlot, null);
+                if (tStack.stackSize == 0) setInventorySlotContents(aPart, aSlot, null);
             }
         }
         return rStack;
@@ -830,30 +941,52 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
 
     @Override
     public ItemStack getStackInSlotOnClosing(MultiBlockPart aPart, int aSlot) {
-        final Pair<ItemStack[], Integer> tInv = getInventory(aPart.getLockedInventory(), aSlot);
+        final Pair<IItemHandlerModifiable, Integer> tInv = getInventory(aPart, aSlot);
         if (tInv == null) return null;
 
-        final ItemStack[] inv = tInv.getLeft();
+        final IItemHandlerModifiable inv = tInv.getLeft();
         final int tSlot = tInv.getRight();
 
-        final ItemStack rStack = inv[tSlot];
-        inv[tSlot] = null;
+        final ItemStack rStack = inv.getStackInSlot(tSlot);
+        inv.setStackInSlot(tSlot, null);
         return rStack;
     }
 
     @Override
     public void setInventorySlotContents(MultiBlockPart aPart, int aSlot, ItemStack aStack) {
-        final Pair<ItemStack[], Integer> tInv = getInventory(aPart.getLockedInventory(), aSlot);
+        final Pair<IItemHandlerModifiable, Integer> tInv = getInventory(aPart, aSlot);
         if (tInv == null) return;
 
-        final ItemStack[] inv = tInv.getLeft();
+        final IItemHandlerModifiable inv = tInv.getLeft();
         final int tSlot = tInv.getRight();
-        inv[tSlot] = aStack;
+        inv.setStackInSlot(tSlot, aStack);
+    }
+
+    @Override
+    public List<String> getInventoryNames(MultiBlockPart aPart) {
+        final List<String> inventoryNames = new ArrayList<>();
+        inventoryNames.add("all");
+        inventoryNames.addAll(getMultiBlockInventory(aPart).keySet());
+        return inventoryNames;
     }
 
     @Override
     public String getInventoryName(MultiBlockPart aPart) {
-        return getInventoryName(); // TODO: MultiInventory: Include part Name?
+        final StringBuilder str = new StringBuilder();
+        str.append(getInventoryName());
+        if (aPart.modeSelected(MultiBlockPart.ITEM_IN)) {
+            str.append(" Input");
+        } else if (aPart.modeSelected(MultiBlockPart.ITEM_OUT)) {
+            str.append(" Output");
+        } else {
+            str.append(" Unknown");
+        }
+        final String lockedInventory = aPart.getLockedInventory();
+        if (lockedInventory != null && !lockedInventory.equals("")) {
+            str.append(" [Locked: ").append(lockedInventory).append("]");
+        }
+
+        return str.toString();
     }
 
     @Override
@@ -868,9 +1001,9 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
 
     @Override
     public void markDirty(MultiBlockPart aPart) {
-        // TODO: MultiInventory - Consider the part?
         markDirty();
-        markInventoryBeenModified();
+        if (aPart.modeSelected(MultiBlockPart.ITEM_OUT)) markOutputInventoryBeenModified();
+        else markInventoryBeenModified();
     }
 
     @Override
@@ -894,4 +1027,165 @@ public abstract class MultiBlockController<T extends MultiBlockController<T>> ex
     public boolean isItemValidForSlot(MultiBlockPart aPart, int aSlot, ItemStack aStack) {
         return isItemValidForSlot(aSlot, aStack);
     }
+
+    /**
+     * GUI Work - Multiblock GUI related methods
+     */
+    @Override
+    public boolean useModularUI() {
+        return true;
+    }
+
+    @Override
+    public ModularWindow createWindow(UIBuildContext buildContext) {
+        System.out.println("MultiBlockController::createWindow");
+        return super.createWindow(buildContext);
+    }
+
+    @Override
+    public boolean hasGui(byte aSide) {
+        return true;
+    }
+
+    @Override
+    protected void addTitleTextStyle(ModularWindow.Builder builder, String title) {
+        // leave empty
+    }
+
+    @Override
+    public void addGregTechLogo(ModularWindow.Builder builder) {
+        builder.widget(new DrawableWidget()
+                .setDrawable(getGUITextureSet().getGregTechLogo())
+                .setSize(17, 17)
+                .setPos(148, 60));
+    }
+
+    @Override
+    public void addUIWidgets(ModularWindow.Builder builder, UIBuildContext buildContext) {
+        builder.widget(new TabContainer()
+                        .setButtonSize(20, 24)
+                        .addTabButton(new TabButton(0)
+                                .setBackground(
+                                        false, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0, 1f, 0.5f))
+                                .setBackground(
+                                        true, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0.5f, 1f, 1f))
+                                .addTooltip(getLocalName())
+                                .setPos(0, -20))
+                        .addTabButton(new TabButton(1)
+                                .setBackground(
+                                        false, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0, 1f, 0.5f))
+                                .setBackground(
+                                        true, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0.5f, 1f, 1f))
+                                .setPos(20, -20))
+                        .addTabButton(new TabButton(2)
+                                .setBackground(
+                                        false, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0, 1f, 0.5f))
+                                .setBackground(
+                                        true, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0.5f, 1f, 1f))
+                                .setPos(40, -20))
+                        .addTabButton(new TabButton(3)
+                                .setBackground(
+                                        false, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0, 1f, 0.5f))
+                                .setBackground(
+                                        true, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0.5f, 1f, 1f))
+                                .setPos(60, -20))
+                        .addTabButton(new TabButton(4)
+                                .setBackground(
+                                        false, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0, 1f, 0.5f))
+                                .setBackground(
+                                        true, ModularUITextures.VANILLA_TAB_TOP_START.getSubArea(0, 0.5f, 1f, 1f))
+                                .setPos(80, -20))
+                        .addPage(new MultiChildWidget()
+                                .addChild(new DrawableWidget()
+                                        .setDrawable(GT_UITextures.PICTURE_SCREEN_BLACK)
+                                        .setPos(7, 4)
+                                        .setSize(160, 75)))
+                        .addPage(new MultiChildWidget().addChild(getItemInventoryInputGUI()))
+                        .addPage(new MultiChildWidget().addChild(getItemInventoryOutputGUI()))
+                        .addPage(new MultiChildWidget().addChild(getFluidInventoryInputGUI()))
+                        .addPage(new MultiChildWidget().addChild(getFluidInventoryOutputGUI())))
+                .widget(new ItemDrawable(getStackForm(1))
+                        .asWidget()
+                        .setSize(16, 16)
+                        .setPos(2, -16))
+                .widget(new DrawableWidget()
+                        .setDrawable(GT_UITextures.PICTURE_ITEM_IN)
+                        .setSize(16, 16)
+                        .setPos(22, -16))
+                .widget(new DrawableWidget()
+                        .setDrawable(GT_UITextures.PICTURE_ITEM_OUT)
+                        .setSize(16, 16)
+                        .setPos(42, -16))
+                .widget(new DrawableWidget()
+                        .setDrawable(GT_UITextures.PICTURE_FLUID_IN)
+                        .setSize(16, 16)
+                        .setPos(62, -16))
+                .widget(new DrawableWidget()
+                        .setDrawable(GT_UITextures.PICTURE_FLUID_OUT)
+                        .setSize(16, 16)
+                        .setPos(82, -16));
+    }
+
+    protected Widget getItemInventoryInputGUI() {
+        final IItemHandlerModifiable inv = getInventoriesForInput();
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < Math.min(inv.getSlots(), 128); rows++) {
+            final int columnsToMake = Math.min(Math.min(inv.getSlots(), 128) - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                scrollable.widget(new SlotWidget(inv, rows * 4 + column)
+                        .setPos(column * 18, rows * 18)
+                        .setSize(18, 18));
+            }
+        }
+        return scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 7);
+    }
+
+    protected Widget getItemInventoryOutputGUI() {
+        final IItemHandlerModifiable inv = getInventoriesForOutput();
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < Math.min(inv.getSlots(), 128); rows++) {
+            final int columnsToMake = Math.min(Math.min(inv.getSlots(), 128) - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                scrollable.widget(new SlotWidget(inv, rows * 4 + column)
+                        .setPos(column * 18, rows * 18)
+                        .setSize(18, 18));
+            }
+        }
+        return scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 7);
+    }
+
+    protected IItemHandlerModifiable getInventoriesForInput() {
+        return new ListItemHandler(multiBlockInputInventory.values());
+    }
+
+    protected IItemHandlerModifiable getInventoriesForOutput() {
+        return new ListItemHandler(multiBlockOutputInventory.values());
+    }
+
+    protected Widget getFluidInventoryInputGUI() {
+        final IFluidTank[] tanks = mTanksInput;
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < tanks.length; rows++) {
+            final int columnsToMake = Math.min(tanks.length - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                final FluidSlotWidget fluidSlot = new FluidSlotWidget(tanks[rows * 4 + column]);
+                scrollable.widget(fluidSlot.setPos(column * 18, rows * 18).setSize(18, 18));
+            }
+        }
+        return scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 7);
+    }
+
+    protected Widget getFluidInventoryOutputGUI() {
+        final IFluidTank[] tanks = mTanksOutput;
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < tanks.length; rows++) {
+            final int columnsToMake = Math.min(tanks.length - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                final FluidSlotWidget fluidSlot = new FluidSlotWidget(tanks[rows * 4 + column]);
+                fluidSlot.setInteraction(true, false);
+                scrollable.widget(fluidSlot.setPos(column * 18, rows * 18).setSize(18, 18));
+            }
+        }
+        return scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 7);
+    }
 }
diff --git a/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockPart.java b/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockPart.java
index 628992a931..36fbf35961 100644
--- a/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockPart.java
+++ b/src/main/java/gregtech/api/multitileentity/multiblock/base/MultiBlockPart.java
@@ -15,6 +15,15 @@ import static gregtech.api.enums.Textures.BlockIcons.OVERLAY_PIPE_IN;
 import static gregtech.api.enums.Textures.BlockIcons.OVERLAY_PIPE_OUT;
 import static org.apache.commons.lang3.ObjectUtils.firstNonNull;
 
+import com.gtnewhorizons.modularui.api.forge.IItemHandlerModifiable;
+import com.gtnewhorizons.modularui.api.screen.ModularWindow;
+import com.gtnewhorizons.modularui.api.screen.ModularWindow.Builder;
+import com.gtnewhorizons.modularui.api.screen.UIBuildContext;
+import com.gtnewhorizons.modularui.common.widget.DrawableWidget;
+import com.gtnewhorizons.modularui.common.widget.DropDownWidget;
+import com.gtnewhorizons.modularui.common.widget.FluidSlotWidget;
+import com.gtnewhorizons.modularui.common.widget.Scrollable;
+import com.gtnewhorizons.modularui.common.widget.SlotWidget;
 import gregtech.api.enums.GT_Values;
 import gregtech.api.enums.Textures;
 import gregtech.api.interfaces.IIconContainer;
@@ -22,11 +31,12 @@ import gregtech.api.interfaces.ITexture;
 import gregtech.api.multitileentity.MultiTileEntityRegistry;
 import gregtech.api.multitileentity.base.BaseNontickableMultiTileEntity;
 import gregtech.api.multitileentity.interfaces.IMultiBlockController;
+import gregtech.api.multitileentity.interfaces.IMultiBlockPart;
 import gregtech.api.multitileentity.interfaces.IMultiTileEntity.IMTE_BreakBlock;
+import gregtech.api.multitileentity.interfaces.IMultiTileEntity.IMTE_HasModes;
 import gregtech.api.render.TextureFactory;
-import gregtech.api.util.GT_CoverBehaviorBase;
 import gregtech.api.util.GT_Utility;
-import gregtech.api.util.ISerializableObject;
+import gregtech.common.covers.CoverInfo;
 import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -44,8 +54,10 @@ import net.minecraftforge.common.util.ForgeDirection;
 import net.minecraftforge.fluids.Fluid;
 import net.minecraftforge.fluids.FluidStack;
 import net.minecraftforge.fluids.FluidTankInfo;
+import net.minecraftforge.fluids.IFluidTank;
 
-public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IMTE_BreakBlock {
+public class MultiBlockPart extends BaseNontickableMultiTileEntity
+        implements IMultiBlockPart, IMTE_BreakBlock, IMTE_HasModes {
     public static final int NOTHING = 0,
             ENERGY_IN = B[0],
             ENERGY_OUT = B[1],
@@ -63,6 +75,9 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
     protected int mAllowedModes = NOTHING; // BITMASK - Modes allowed for this part
     protected byte mMode = 0; // Mode selected for this part
 
+    protected String mLockedInventory = GT_Values.E;
+    protected int mLockedInventoryIndex = 0;
+
     /**
      * What Part Tier is this part?  All Basic Casings are Tier 1, and will allow:
      *  Energy, Item, Fluid input/output.  Some of the more advanced modes can be set to require a higher tier part.
@@ -71,14 +86,15 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
         return 1;
     }
 
-    public int getLockedInventory() {
-        return -1;
+    public String getLockedInventory() {
+        return mLockedInventory.equals("") ? null : mLockedInventory;
     }
 
     public void setTarget(IMultiBlockController aTarget, int aAllowedModes) {
         mTarget = aTarget;
         mTargetPos = (mTarget == null ? null : mTarget.getCoords());
         mAllowedModes = aAllowedModes;
+        if (mTarget != null) registerCovers(mTarget);
     }
 
     @Override
@@ -106,6 +122,8 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
                 final TileEntity te = worldObj.getTileEntity(mTargetPos.posX, mTargetPos.posY, mTargetPos.posZ);
                 if (te instanceof IMultiBlockController) {
                     mTarget = (IMultiBlockController) te;
+                    // Register our covers with the controller
+                    registerCovers(mTarget);
                 } else {
                     mTargetPos = null;
                 }
@@ -116,6 +134,46 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
         } else return mTarget;
     }
 
+    public void registerCovers(IMultiBlockController controller) {
+        for (byte i : ALL_VALID_SIDES) {
+            final CoverInfo coverInfo = getCoverInfoAtSide(i);
+            if (coverInfo.isValid() && coverInfo.getTickRate() > 0) {
+                controller.registerCoveredPartOnSide(i, this);
+            }
+        }
+    }
+
+    @Override
+    public void setCoverItemAtSide(byte aSide, ItemStack aCover) {
+        super.setCoverItemAtSide(aSide, aCover);
+        // TODO: Filter on tickable covers
+        final IMultiBlockController tTarget = getTarget(true);
+        if (tTarget != null) {
+            final CoverInfo coverInfo = getCoverInfoAtSide(aSide);
+            if (coverInfo.isValid() && coverInfo.getTickRate() > 0) {
+                tTarget.registerCoveredPartOnSide(aSide, this);
+            }
+        }
+    }
+
+    public void unregisterCovers(IMultiBlockController controller) {
+        for (byte i : ALL_VALID_SIDES) {
+            if (getCoverInfoAtSide(i).isValid()) {
+                controller.unregisterCoveredPartOnSide(i, this);
+            }
+        }
+    }
+
+    @Override
+    public boolean dropCover(byte aSide, byte aDroppedSide, boolean aForced) {
+        final boolean res = super.dropCover(aSide, aDroppedSide, aForced);
+        final IMultiBlockController tTarget = getTarget(true);
+        if (tTarget != null) {
+            tTarget.unregisterCoveredPartOnSide(aSide, this);
+        }
+        return res;
+    }
+
     @Override
     public void readMultiTileNBT(NBTTagCompound aNBT) {
         if (aNBT.hasKey(NBT.ALLOWED_MODES)) mAllowedModes = aNBT.getInteger(NBT.ALLOWED_MODES);
@@ -124,6 +182,12 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
             mTargetPos = new ChunkCoordinates(
                     aNBT.getInteger(NBT.TARGET_X), aNBT.getShort(NBT.TARGET_Y), aNBT.getInteger(NBT.TARGET_Z));
         }
+        if (aNBT.hasKey(NBT.LOCKED_INVENTORY)) {
+            mLockedInventory = aNBT.getString(NBT.LOCKED_INVENTORY);
+        }
+        if (aNBT.hasKey(NBT.LOCKED_INVENTORY_INDEX)) {
+            mLockedInventoryIndex = aNBT.getInteger(NBT.LOCKED_INVENTORY_INDEX);
+        }
     }
 
     @Override
@@ -136,12 +200,49 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
             aNBT.setShort(NBT.TARGET_Y, (short) mTargetPos.posY);
             aNBT.setInteger(NBT.TARGET_Z, mTargetPos.posZ);
         }
+        if (mLockedInventory != null) {
+            aNBT.setString(NBT.LOCKED_INVENTORY, mLockedInventory);
+        }
+        if (mLockedInventoryIndex != 0) {
+            aNBT.setInteger(NBT.LOCKED_INVENTORY_INDEX, mLockedInventoryIndex);
+        }
+    }
+
+    @Override
+    public void setTargetPos(ChunkCoordinates aTargetPos) {
+        mTargetPos = aTargetPos;
+    }
+
+    @Override
+    public ChunkCoordinates getTargetPos() {
+        return mTargetPos;
+    }
+
+    @Override
+    public void setMode(byte aMode) {
+        mMode = aMode;
+    }
+
+    @Override
+    public byte getMode() {
+        return mMode;
+    }
+
+    @Override
+    public int getAllowedModes() {
+        return mAllowedModes;
+    }
+
+    @Override
+    public void setAllowedModes(int aAllowedModes) {
+        mAllowedModes = aAllowedModes;
     }
 
     /**
      * True if `aMode` is one of the allowed modes
      */
     public boolean hasMode(int aMode) {
+        // This is not sent to the client
         return (mAllowedModes & aMode) != 0;
     }
 
@@ -158,7 +259,10 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
     @Override
     public boolean breakBlock() {
         final IMultiBlockController tTarget = getTarget(false);
-        if (tTarget != null) tTarget.onStructureChange();
+        if (tTarget != null) {
+            unregisterCovers(tTarget);
+            tTarget.onStructureChange();
+        }
         return false;
     }
 
@@ -176,16 +280,6 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
     }
 
     @Override
-    public byte getTextureData() {
-        return mMode;
-    }
-
-    @Override
-    public void setTextureData(byte aData) {
-        mMode = aData;
-    }
-
-    @Override
     public void loadTextureNBT(NBTTagCompound aNBT) {
         // Loading the registry
         final String textureName = aNBT.getString(NBT.TEXTURE);
@@ -365,13 +459,10 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
         final IMultiBlockController controller = getTarget(true);
         if (controller == null) return GT_Values.emptyFluidTankInfo;
 
-        final GT_CoverBehaviorBase<?> tCover = getCoverBehaviorAtSideNew(aSide);
-        final int coverId = getCoverIDAtSide(aSide);
-        final ISerializableObject complexCoverData = getComplexCoverDataAtSide(aSide);
+        final CoverInfo coverInfo = getCoverInfoAtSide(aSide);
 
-        if ((controller.isLiquidInput(aSide) && tCover.letsFluidIn(aSide, coverId, complexCoverData, null, controller))
-                || (controller.isLiquidOutput(aSide)
-                        && tCover.letsFluidOut(aSide, coverId, complexCoverData, null, controller)))
+        if ((controller.isLiquidInput(aSide) && coverInfo.letsFluidIn(null, controller))
+                || (controller.isLiquidOutput(aSide) && coverInfo.letsFluidOut(null, controller)))
             return controller.getTankInfo(this, aDirection);
 
         return GT_Values.emptyFluidTankInfo;
@@ -441,7 +532,7 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     @Override
     public boolean decreaseStoredEnergyUnits(long aEnergy, boolean aIgnoreTooLittleEnergy) {
-        if (!modeSelected(ENERGY_IN)) return false;
+        if (!modeSelected(ENERGY_OUT)) return false;
         final IMultiBlockController controller = getTarget(true);
         return controller != null
                 && hasMode(ENERGY_OUT)
@@ -536,14 +627,14 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     @Override
     public boolean addStackToSlot(int aIndex, ItemStack aStack) {
-        if (!modeSelected(ITEM_IN)) return false;
+        if (!modeSelected(ITEM_IN, ITEM_OUT)) return false;
         final IMultiBlockController controller = getTarget(true);
         return (controller != null && controller.addStackToSlot(this, aIndex, aStack));
     }
 
     @Override
     public boolean addStackToSlot(int aIndex, ItemStack aStack, int aAmount) {
-        if (!modeSelected(ITEM_IN)) return false;
+        if (!modeSelected(ITEM_IN, ITEM_OUT)) return false;
         final IMultiBlockController controller = getTarget(true);
         return (controller != null && controller.addStackToSlot(this, aIndex, aStack, aAmount));
     }
@@ -558,7 +649,7 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     @Override
     public boolean canInsertItem(int aSlot, ItemStack aStack, int aSide) {
-        if (!modeSelected(ITEM_IN)
+        if (!modeSelected(ITEM_IN, ITEM_OUT)
                 || (mFacing != SIDE_UNKNOWN && (mFacing != aSide || !coverLetsItemsIn((byte) aSide, aSlot))))
             return false;
         final IMultiBlockController controller = getTarget(true);
@@ -567,7 +658,7 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     @Override
     public boolean canExtractItem(int aSlot, ItemStack aStack, int aSide) {
-        if (!modeSelected(ITEM_OUT)
+        if (!modeSelected(ITEM_IN, ITEM_OUT)
                 || (mFacing != SIDE_UNKNOWN && (mFacing != aSide || !coverLetsItemsOut((byte) aSide, aSlot))))
             return false;
         final IMultiBlockController controller = getTarget(true);
@@ -590,7 +681,7 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     @Override
     public ItemStack decrStackSize(int aSlot, int aDecrement) {
-        if (!modeSelected(ITEM_OUT)) return null;
+        if (!modeSelected(ITEM_IN, ITEM_OUT)) return null;
         final IMultiBlockController controller = getTarget(true);
         return controller != null ? controller.decrStackSize(this, aSlot, aDecrement) : null;
     }
@@ -628,4 +719,131 @@ public class MultiBlockPart extends BaseNontickableMultiTileEntity implements IM
 
     // End Inventory
 
+    // === Modular UI ===
+    @Override
+    public boolean useModularUI() {
+        return true;
+    }
+
+    @Override
+    public String getLocalName() {
+        if (modeSelected(ITEM_IN)) return "Input Inventory";
+        if (modeSelected(ITEM_OUT)) return "Output Inventory";
+        if (modeSelected(FLUID_IN)) return "Fluid Input Hatch";
+        if (modeSelected(FLUID_OUT)) return "Fluid Output Hatch";
+
+        return "Unknown";
+    }
+
+    @Override
+    public boolean hasGui(byte aSide) {
+        // UIs only for specific mode(s)
+        if (modeSelected(ITEM_IN, ITEM_OUT, FLUID_IN, FLUID_OUT)) return true;
+
+        return false;
+    }
+
+    protected void addItemInventory(Builder builder, UIBuildContext buildContext) {
+        final IMultiBlockController controller = getTarget(false);
+        if (controller == null) {
+            return;
+        }
+        final IItemHandlerModifiable inv = controller.getInventoryForGUI(this);
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < Math.min(inv.getSlots(), 128); rows++) {
+            int columnsToMake = Math.min(Math.min(inv.getSlots(), 128) - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                scrollable.widget(new SlotWidget(inv, rows * 4 + column)
+                        .setPos(column * 18, rows * 18)
+                        .setSize(18, 18));
+            }
+        }
+        builder.widget(scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 18));
+        DropDownWidget dropDown = new DropDownWidget();
+        builder.widget(dropDown.addDropDownItemsSimple(
+                        controller.getInventoryNames(this),
+                        (buttonWidget, index, label, setSelected) -> buttonWidget.setOnClick((clickData, widget) -> {
+                            if (getNameOfInventoryFromIndex(controller, index).equals("all")) {
+                                mLockedInventory = GT_Values.E;
+                                mLockedInventoryIndex = 0;
+                            } else {
+                                mLockedInventory = getNameOfInventoryFromIndex(controller, index);
+                                mLockedInventoryIndex = index;
+                            }
+                            setSelected.run();
+                        }),
+                        true)
+                .setSelected(mLockedInventoryIndex)
+                .setExpandedMaxHeight(60)
+                .setDirection(DropDownWidget.Direction.DOWN)
+                .setPos(53, 5)
+                .setSize(70, 11));
+    }
+
+    protected String getNameOfInventoryFromIndex(final IMultiBlockController controller, int index) {
+        final List<String> invNames = controller.getInventoryNames(this);
+        if (index > invNames.size()) {
+            return invNames.get(0);
+        }
+        return invNames.get(index);
+    }
+
+    protected void addFluidInventory(Builder builder, UIBuildContext buildContext) {
+        final IMultiBlockController controller = getTarget(false);
+        if (controller == null) {
+            return;
+        }
+        final IFluidTank[] tanks = controller.getFluidTanksForGUI(this);
+        final Scrollable scrollable = new Scrollable().setVerticalScroll();
+        for (int rows = 0; rows * 4 < tanks.length; rows++) {
+            int columnsToMake = Math.min(tanks.length - rows * 4, 4);
+            for (int column = 0; column < columnsToMake; column++) {
+                FluidSlotWidget fluidSlot = new FluidSlotWidget(tanks[rows * 4 + column]);
+                if (modeSelected(FLUID_OUT)) {
+                    fluidSlot.setInteraction(true, false);
+                }
+                scrollable.widget(fluidSlot.setPos(column * 18, rows * 18).setSize(18, 18));
+            }
+        }
+        builder.widget(scrollable.setSize(18 * 4 + 4, 18 * 4).setPos(52, 7));
+    }
+
+    @Override
+    public void addUIWidgets(Builder builder, UIBuildContext buildContext) {
+        if (modeSelected(ITEM_IN, ITEM_OUT)) {
+            addItemInventory(builder, buildContext);
+        }
+        if (modeSelected(FLUID_IN, FLUID_OUT)) {
+            addFluidInventory(builder, buildContext);
+        }
+    }
+
+    @Override
+    public ModularWindow createWindow(UIBuildContext buildContext) {
+        if (isServerSide()) {
+            issueClientUpdate();
+        }
+        System.out.println("MultiBlockPart::createWindow");
+        return super.createWindow(buildContext);
+    }
+
+    @Override
+    protected int getGUIHeight() {
+        if (modeSelected(ITEM_IN, ITEM_OUT)) {
+            return super.getGUIHeight() + 11;
+        }
+        return super.getGUIHeight();
+    }
+
+    @Override
+    public void addGregTechLogo(Builder builder) {
+        if (modeSelected(ITEM_IN, ITEM_OUT)) {
+            builder.widget(new DrawableWidget()
+                    .setDrawable(getGUITextureSet().getGregTechLogo())
+                    .setSize(17, 17)
+                    .setPos(152, 74));
+        } else {
+            super.addGregTechLogo(builder);
+        }
+    }
 }