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package com.notnite.gloppers.mixin;

import com.notnite.gloppers.Gloppers;
import net.minecraft.block.entity.Hopper;
import net.minecraft.block.entity.HopperBlockEntity;
import net.minecraft.inventory.Inventory;
import net.minecraft.item.ItemStack;
import net.minecraft.util.math.Direction;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.spongepowered.asm.mixin.injection.Redirect;
import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;

@Mixin(HopperBlockEntity.class)
public class HopperBlockEntityMixin {
    private static int dirtySlotState = 0;

    // We can't decrement the item stack before it gets passed to transfer, because we may not be allowed to transfer,
    // eating an item. We know removeStack will get called immediately before transfer, so while it's messy, we can use
    // a static variable to keep track of what slot we're removing from.
    @Redirect(
        method = "insert",
        at = @At(value = "INVOKE", target = "Lnet/minecraft/inventory/Inventory;removeStack(II)Lnet/minecraft/item/ItemStack;")
    )
    private static ItemStack insert$gloppersRemoveStack(Inventory instance, int slot, int amount) {
        dirtySlotState = slot;
        return instance.getStack(slot);
    }

    // This works by mixing into the call of HopperBlockEntity::transfer and returning a stubbed item stack if it's not
    // allowed to transfer. I wanted to instead insert a continue statement into the for loop, but I couldn't figure out
    // a good way to do that.
    @Redirect(
        method = "insert",
        at = @At(value = "INVOKE", target = "Lnet/minecraft/block/entity/HopperBlockEntity;transfer(Lnet/minecraft/inventory/Inventory;Lnet/minecraft/inventory/Inventory;Lnet/minecraft/item/ItemStack;Lnet/minecraft/util/math/Direction;)Lnet/minecraft/item/ItemStack;")
    )
    private static ItemStack insert$gloppersTransfer(
        Inventory from, Inventory to, ItemStack stack, Direction side
    ) {
        if (!Gloppers.INSTANCE.canTransfer(to, stack)) {
            // The return value of this is only used to check if it's empty, and if so, returns that it succeeded.
            // We can just return the item stack we were given, as we didn't remove from it.
            return stack;
        }

        // Make sure to remove the item here, because we didn't in the actual call.
        return HopperBlockEntity.transfer(from, to, from.removeStack(dirtySlotState, 1), side);
    }

    // This handles the case where a hopper extracts from a hopper above it (such as two anvils facing forward, stacked
    // on top of one another).
    @Inject(
        method = "extract(Lnet/minecraft/block/entity/Hopper;Lnet/minecraft/inventory/Inventory;ILnet/minecraft/util/math/Direction;)Z",
        at = @At("HEAD"),
        cancellable = true
    )
    private static void extract(Hopper hopper, Inventory inventory, int slot, Direction side, CallbackInfoReturnable<Boolean> cir) {
        var item = inventory.getStack(slot);
        if (!Gloppers.INSTANCE.canTransfer(hopper, item)) cir.setReturnValue(false);
    }
}