package chess.view.DDDrender;

import common.AssetManager;
import common.Signal0;
import org.joml.Vector2f;
import org.lwjgl.*;
import org.lwjgl.glfw.*;
import org.lwjgl.opengl.*;
import org.lwjgl.system.*;

import chess.model.Coordinate;
import chess.view.DDDrender.opengl.FrameBuffer;
import chess.view.DDDrender.world.Entity;
import chess.view.DDDrender.world.World;
import common.Signal1;
import imgui.ImFontConfig;
import imgui.ImGui;
import imgui.ImVec2;
import imgui.flag.ImGuiWindowFlags;
import imgui.gl3.ImGuiImplGl3;
import imgui.glfw.ImGuiImplGlfw;
import imgui.type.ImBoolean;
import imgui.type.ImInt;

import java.io.Closeable;
import java.io.IOException;
import java.nio.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.function.Consumer;

import static org.lwjgl.glfw.Callbacks.*;
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.system.MemoryStack.*;
import static org.lwjgl.system.MemoryUtil.*;

public class Window implements Closeable {

	// The window handle
	private long window;

	private final ImGuiImplGl3 implGl3 = new ImGuiImplGl3();
	private final ImGuiImplGlfw implGlfw = new ImGuiImplGlfw();

	private Renderer renderer;
	private final Camera cam;
	private final World world;

	private final Queue<Runnable> tasks;
	private final List<Consumer<Float>> regularTasks;

	private Coordinate lastCell = null;

	public final Signal1<Coordinate> OnCellClick = new Signal1<>();
	public final Signal1<Coordinate> OnCellEnter = new Signal1<>();
	public final Signal1<Coordinate> OnCellExit = new Signal1<>();

	public final Signal0 OnImGuiTopRender = new Signal0();
	public final Signal0 OnImGuiBottomRender = new Signal0();

	private ImInt detailLevel = new ImInt(10);
	private ImBoolean pixelatedFrame = new ImBoolean(true);

	public Window(Renderer renderer, World world, Camera camera) {
		this.renderer = new Renderer();
		this.cam = camera;
		this.tasks = new ConcurrentLinkedDeque<>();
		this.world = world;
		this.regularTasks = new ArrayList<>();
	}

	public synchronized void addRegularTask(Consumer<Float> task) {
		this.regularTasks.add(task);
	}

	public synchronized void removeRegularTask(Consumer<Float> task) {this.regularTasks.remove(task);}

	public synchronized void scheduleTask(Runnable runnable) {
		this.tasks.add(runnable);
	}

	public synchronized Runnable getNextTask() {
		return this.tasks.poll();
	}

	public void run() {
		System.out.println("LWJGL " + Version.getVersion() + "!");

		init();
		loop();

		// Free the window callbacks and destroy the window
		glfwFreeCallbacks(window);
		glfwDestroyWindow(window);

		// Terminate GLFW and free the error callback
		glfwTerminate();
		glfwSetErrorCallback(null).free();

		implGl3.shutdown();
		implGlfw.shutdown();

		ImGui.destroyContext();
	}

	private void initImGui() {
		ImGui.setCurrentContext(ImGui.createContext());

		implGl3.init("#version 330");
		implGlfw.init(window, true);

		ImFontConfig config = new ImFontConfig();
		config.setFontDataOwnedByAtlas(false);
		try {
			ImGui.getIO().getFonts().addFontFromMemoryTTF(AssetManager.getResource("fonts/comic.ttf").readAllBytes(),
					50.0f, config);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	private void init() {
		// Setup an error callback. The default implementation
		// will print the error message in System.err.
		GLFWErrorCallback.createPrint(System.err).set();

		// Initialize GLFW. Most GLFW functions will not work before doing this.
		if (!glfwInit())
			throw new IllegalStateException("Unable to initialize GLFW");

		// Configure GLFW
		glfwDefaultWindowHints(); // optional, the current window hints are already the default
		glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); // the window will stay hidden after creation
		glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); // the window will be resizable

		// Create the window
		window = glfwCreateWindow(1000, 1000, "3DChess", NULL, NULL);
		if (window == NULL)
			throw new RuntimeException("Failed to create the GLFW window");

		// Get the thread stack and push a new frame
		try (MemoryStack stack = stackPush()) {
			IntBuffer pWidth = stack.mallocInt(1); // int*
			IntBuffer pHeight = stack.mallocInt(1); // int*

			// Get the window size passed to glfwCreateWindow
			glfwGetWindowSize(window, pWidth, pHeight);

			// Get the resolution of the primary monitor
			GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());

			// Center the window
			glfwSetWindowPos(
					window,
					(vidmode.width() - pWidth.get(0)) / 2,
					(vidmode.height() - pHeight.get(0)) / 2);

			glfwSetWindowSize(window, vidmode.width(), vidmode.height());
			
			// Make the OpenGL context current
			glfwMakeContextCurrent(window);
			
			GL.createCapabilities();
			
			initImGui();
			
			renderer.Init(vidmode.width(), vidmode.height());
		} // the stack frame is popped automatically

		// Enable v-sync
		glfwSwapInterval(1);

		// Make the window visible
		glfwShowWindow(window);
	}

	private void render(float delta, float aspectRatio) {
		final FrameBuffer frameBuffer = this.renderer.getFrameBuffer();

		cam.setAspectRatio(frameBuffer.getAspectRatio());
		frameBuffer.Bind();
		frameBuffer.Clear();
		renderer.Update(cam);
		renderWorld();
		frameBuffer.Unbind();
	}

	private void renderWorld() {
		for (Entity entity : this.world.getEntites()) {
			entity.render(this.renderer);
		}
	}

	private synchronized void executeTasks(float delta) {
		Runnable task = getNextTask();
		while (task != null) {
			task.run();
			task = getNextTask();
		}
		for (Consumer<Float> consumer : regularTasks) {
			consumer.accept(delta);
		}
	}

	private void checkCursor(float cursorPosX, float cursorPosY, int windowWidth, int windowHeight) {
		Vector2f cursorPos = this.cam.getCursorWorldFloorPos(new Vector2f(cursorPosX, cursorPosY), windowWidth,
				windowHeight);
		Coordinate selectedCell = DDDPlacement.vectorToCoordinates(cursorPos);
		if (this.lastCell == null) {
			this.lastCell = selectedCell;
			if (selectedCell.isValid())
				this.OnCellEnter.emit(selectedCell);
		} else if (!this.lastCell.equals(selectedCell)) {
			if (this.lastCell.isValid())
				this.OnCellExit.emit(this.lastCell);
			if (selectedCell.isValid())
				this.OnCellEnter.emit(selectedCell);
			this.lastCell = selectedCell;
		}

		if (ImGui.getIO().getMouseClicked(0)) {
			if (this.lastCell != null && this.lastCell.isValid())
				this.OnCellClick.emit(this.lastCell);
		}
	}

	private void newFrame() {
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer

		implGlfw.newFrame();
		implGl3.newFrame();
		ImGui.newFrame();
	}

	private void renderWindow() {
		ImGui.showDemoWindow();

		final FrameBuffer frameBuffer = this.renderer.getFrameBuffer();
		final int frameWidth = (int) ImGui.getIO().getDisplaySizeX();
		final int frameHeight = (int) (ImGui.getIO().getDisplaySizeY() * 8.0f / 10.0f);

		ImGui.setNextWindowSize(ImGui.getIO().getDisplaySize());
		ImGui.setNextWindowPos(new ImVec2());
		ImGui.begin("Main Window", ImGuiWindowFlags.NoDecoration);
		this.OnImGuiTopRender.emit();
		ImVec2 mousePos = ImGui.getIO().getMousePos();
		ImVec2 framePos = ImGui.getCursorScreenPos();
		checkCursor(mousePos.x - framePos.x, frameHeight - (mousePos.y - framePos.y), frameWidth, frameHeight);
		ImGui.image(frameBuffer.getRenderTexture(), new ImVec2(frameWidth, frameHeight));
		this.OnImGuiBottomRender.emit();
		if(ImGui.sliderInt("Niveau de détail", detailLevel.getData(), 1, 10)){
			frameBuffer.Resize((int) ((float) frameWidth * detailLevel.get() / 10.0f), (int) ((float) frameHeight * detailLevel.get() / 10.0f));
		}
		if (ImGui.checkbox("Minecraft", pixelatedFrame)) {
			frameBuffer.SetPixelScaling(pixelatedFrame.get());
		}
		ImGui.end();
	}

	private void loop() {

		// Set the clear color
		glClearColor(0.4f, 0.4f, 0.6f, 1.0f);

		glEnable(GL_DEPTH_TEST);

		glEnable(GL_CULL_FACE);
		glCullFace(GL_FRONT);
		glFrontFace(GL_CW);

		glColor4f(1.0f, 0.0f, 0.0f, 1.0f);

		int width[] = new int[1];
		int height[] = new int[1];
		glfwGetWindowSize(window, width, height);

		// Run the rendering loop until the user has attempted to close
		// the window or has pressed the ESCAPE key.
		while (!glfwWindowShouldClose(window)) {

			newFrame();

			render(ImGui.getIO().getDeltaTime(), (float) width[0] / (float) height[0]);

			renderWindow();
			ImGui.render();
			implGl3.renderDrawData(ImGui.getDrawData());

			glfwSwapBuffers(window); // swap the color buffers

			// Poll for window events. The key callback above will only be
			// invoked during this call.
			glfwPollEvents();

			executeTasks(ImGui.getIO().getDeltaTime());

			glfwGetWindowSize(window, width, height);
			glViewport(0, 0, width[0], height[0]);

		}
	}

	@Override
	public void close() throws IOException {
		this.renderer.close();
	}

}