package com.mojang.blaze3d.platform;

import com.mojang.blaze3d.systems.RenderSystem;
import com.mojang.logging.LogUtils;
import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
import org.jspecify.annotations.Nullable;
import org.lwjgl.PointerBuffer;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.glfw.GLFWMonitorCallback;
import org.slf4j.Logger;

public class MonitorManager implements AutoCloseable {
	private static final Logger LOGGER = LogUtils.getLogger();
	private final Long2ObjectMap<Monitor> monitors = new Long2ObjectOpenHashMap<>();

	public MonitorManager() {
		GLFW.glfwSetMonitorCallback(this::onMonitorChange);
		PointerBuffer buffer = GLFW.glfwGetMonitors();
		if (buffer != null) {
			for (int i = 0; i < buffer.limit(); i++) {
				Monitor monitor = Monitor.tryCreate(buffer.get(i));
				if (monitor != null) {
					this.monitors.put(buffer.get(i), monitor);
				}
			}
		}
	}

	private void onMonitorChange(final long monitorHandle, final int event) {
		RenderSystem.assertOnRenderThread();
		if (event == 262145) {
			Monitor monitor = Monitor.tryCreate(monitorHandle);
			if (monitor != null) {
				this.monitors.put(monitorHandle, monitor);
				LOGGER.debug("Monitor {} connected. Current monitors: {}", monitor, this.monitors);
			}
		} else if (event == 262146) {
			Monitor monitor = this.monitors.remove(monitorHandle);
			LOGGER.debug("Monitor {} disconnected. Current monitors: {}", monitor != null ? monitor : monitorHandle, this.monitors);
		}
	}

	public @Nullable Monitor getMonitor(final long monitor) {
		return this.monitors.get(monitor);
	}

	public @Nullable Monitor findBestMonitor(final Window window) {
		long windowMonitor = GLFW.glfwGetWindowMonitor(window.handle());
		if (windowMonitor != 0L) {
			return this.getMonitor(windowMonitor);
		}

		int winMinX = window.getX();
		int winMaxX = winMinX + window.getScreenWidth();
		int winMinY = window.getY();
		int winMaxY = winMinY + window.getScreenHeight();
		int maxArea = -1;
		Monitor result = null;
		long primaryMonitor = GLFW.glfwGetPrimaryMonitor();
		LOGGER.debug("Selecting monitor - primary: {}, current monitors: {}", primaryMonitor, this.monitors);

		for (Monitor monitor : this.monitors.values()) {
			int monMinX = monitor.x();
			int monMaxX = monMinX + monitor.currentMode().getWidth();
			int monMinY = monitor.y();
			int monMaxY = monMinY + monitor.currentMode().getHeight();
			int minX = clamp(winMinX, monMinX, monMaxX);
			int maxX = clamp(winMaxX, monMinX, monMaxX);
			int minY = clamp(winMinY, monMinY, monMaxY);
			int maxY = clamp(winMaxY, monMinY, monMaxY);
			int sx = Math.max(0, maxX - minX);
			int sy = Math.max(0, maxY - minY);
			int area = sx * sy;
			if (area > maxArea) {
				result = monitor;
				maxArea = area;
			} else if (area == maxArea && primaryMonitor == monitor.monitor()) {
				LOGGER.debug("Primary monitor {} is preferred to monitor {}", monitor, result);
				result = monitor;
			}
		}

		LOGGER.debug("Selected monitor: {}", result);
		return result;
	}

	public static int clamp(final int value, final int min, final int max) {
		if (value < min) {
			return min;
		} else {
			return value > max ? max : value;
		}
	}

	@Override
	public void close() {
		RenderSystem.assertOnRenderThread();
		GLFWMonitorCallback callback = GLFW.glfwSetMonitorCallback(null);
		if (callback != null) {
			callback.free();
		}
	}
}