1 files changed, 123 insertions, 0 deletions
diff --git a/src/main/java/me/xmrvizzy/skyblocker/utils/scheduler/Scheduler.java b/src/main/java/me/xmrvizzy/skyblocker/utils/scheduler/Scheduler.java
new file mode 100644
index 00000000..76112e0d
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+++ b/src/main/java/me/xmrvizzy/skyblocker/utils/scheduler/Scheduler.java
@@ -0,0 +1,123 @@
+package me.xmrvizzy.skyblocker.utils.scheduler;
+
+import com.mojang.brigadier.Command;
+import me.xmrvizzy.skyblocker.SkyblockerMod;
+import net.fabricmc.fabric.api.client.command.v2.FabricClientCommandSource;
+import net.minecraft.client.MinecraftClient;
+import net.minecraft.client.gui.screen.Screen;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.PriorityQueue;
+import java.util.function.Supplier;
+
+/**
+ * A scheduler for running tasks at a later time. Tasks will be run synchronously on the main client thread. Use the instance stored in {@link SkyblockerMod#scheduler}. Do not instantiate this class.
+ */
+public class Scheduler {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Scheduler.class);
+    private int currentTick = 0;
+    private final PriorityQueue<ScheduledTask> tasks = new PriorityQueue<>();
+
+    /**
+     * Do not instantiate this class. Use {@link SkyblockerMod#scheduler} instead.
+     */
+    @SuppressWarnings("DeprecatedIsStillUsed")
+    @Deprecated
+    public Scheduler() {
+    }
+
+    /**
+     * Schedules a task to run after a delay.
+     *
+     * @param task  the task to run
+     * @param delay the delay in ticks
+     */
+    public void schedule(Runnable task, int delay) {
+        if (delay < 0) {
+            LOGGER.warn("Scheduled a task with negative delay");
+        }
+        ScheduledTask tmp = new ScheduledTask(task, currentTick + delay);
+        tasks.add(tmp);
+    }
+
+    /**
+     * Schedules a task to run every period ticks.
+     *
+     * @param task   the task to run
+     * @param period the period in ticks
+     */
+    public void scheduleCyclic(Runnable task, int period) {
+        if (period <= 0) {
+            LOGGER.error("Attempted to schedule a cyclic task with period lower than 1");
+        } else {
+            new CyclicTask(task, period).run();
+        }
+    }
+
+    public static Command<FabricClientCommandSource> queueOpenScreenCommand(Supplier<Screen> screenSupplier) {
+        return context -> SkyblockerMod.getInstance().scheduler.queueOpenScreen(screenSupplier);
+    }
+
+    /**
+     * Schedules a screen to open in the next tick. Used in commands to avoid screen immediately closing after the command is executed.
+     *
+     * @param screenSupplier the supplier of the screen to open
+     * @see #queueOpenScreenCommand(Supplier)
+     */
+    public int queueOpenScreen(Supplier<Screen> screenSupplier) {
+        MinecraftClient.getInstance().send(() -> MinecraftClient.getInstance().setScreen(screenSupplier.get()));
+        return Command.SINGLE_SUCCESS;
+    }
+
+    public void tick() {
+        currentTick += 1;
+        ScheduledTask task;
+        while ((task = tasks.peek()) != null && task.schedule <= currentTick && runTask(task)) {
+            tasks.poll();
+        }
+    }
+
+    /**
+     * Runs the task if able.
+     *
+     * @param task the task to run
+     * @return {@code true} if the task is run, and {@link false} if task is not run.
+     */
+    protected boolean runTask(Runnable task) {
+        task.run();
+        return true;
+    }
+
+    /**
+     * A task that runs every period ticks. More specifically, this task reschedules itself to run again after period ticks every time it runs.
+     *
+     * @param inner  the task to run
+     * @param period the period in ticks
+     */
+    protected record CyclicTask(Runnable inner, int period) implements Runnable {
+        @Override
+        public void run() {
+            SkyblockerMod.getInstance().scheduler.schedule(this, period);
+            inner.run();
+        }
+    }
+
+    /**
+     * A task that runs at a specific tick, relative to {@link #currentTick}.
+     *
+     * @param inner    the task to run
+     * @param schedule the tick to run at
+     */
+    protected record ScheduledTask(Runnable inner, int schedule) implements Comparable<ScheduledTask>, Runnable {
+        @Override
+        public int compareTo(ScheduledTask o) {
+            return schedule - o.schedule;
+        }
+
+        @Override
+        public void run() {
+            inner.run();
+        }
+    }
+}