package com.chuangzhou.vivid2D.test;

import com.chuangzhou.vivid2D.render.ModelRender;
import com.chuangzhou.vivid2D.render.model.Model2D;
import com.chuangzhou.vivid2D.render.model.ModelPart;
import com.chuangzhou.vivid2D.render.model.util.Mesh2D;
import com.chuangzhou.vivid2D.render.model.util.Texture;
import com.chuangzhou.vivid2D.render.model.util.PhysicsSystem;
import com.chuangzhou.vivid2D.render.systems.RenderSystem;
import org.joml.Vector2f;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.glfw.GLFWVidMode;
import org.lwjgl.opengl.GL;
import org.lwjgl.system.MemoryUtil;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

/**
 * 物理系统使用实例 - 演示弹簧、重力和碰撞效果
 * @author tzdwindows 7
 */
public class ModelTest2 {

    private static final int WINDOW_WIDTH = 1000;
    private static final int WINDOW_HEIGHT = 700;
    private static final String WINDOW_TITLE = "Physics System Demo";

    private long window;
    private boolean running = true;
    private Model2D physicsModel;
    private PhysicsSystem physics;

    // 测试用例控制
    private int testCase = 5;
    private boolean gravityEnabled = true;
    private boolean springsEnabled = true;

    // 存储部件引用，用于清理
    private List<ModelPart> currentParts = new ArrayList<>();

    // 所有测试基点（初始 xy = 0,0）
    private final Vector2f initialOrigin = new Vector2f(0, 0);

    public static void main(String[] args) {
        new ModelTest2().run();
    }

    public void run() {
        try {
            init();
            loop();
        } catch (Throwable t) {
            t.printStackTrace();
        } finally {
            cleanup();
        }
    }

    private void init() {
        GLFWErrorCallback.createPrint(System.err).set();

        if (!GLFW.glfwInit()) {
            throw new IllegalStateException("Unable to initialize GLFW");
        }

        GLFW.glfwDefaultWindowHints();
        GLFW.glfwWindowHint(GLFW.GLFW_VISIBLE, GLFW.GLFW_FALSE);
        GLFW.glfwWindowHint(GLFW.GLFW_RESIZABLE, GLFW.GLFW_TRUE);
        GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MAJOR, 3);
        GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MINOR, 3);
        GLFW.glfwWindowHint(GLFW.GLFW_OPENGL_PROFILE, GLFW.GLFW_OPENGL_CORE_PROFILE);
        GLFW.glfwWindowHint(GLFW.GLFW_OPENGL_FORWARD_COMPAT, GLFW.GLFW_TRUE);

        window = GLFW.glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, WINDOW_TITLE, MemoryUtil.NULL, MemoryUtil.NULL);
        if (window == MemoryUtil.NULL) throw new RuntimeException("Failed to create GLFW window");

        GLFWVidMode vidMode = GLFW.glfwGetVideoMode(GLFW.glfwGetPrimaryMonitor());
        GLFW.glfwSetWindowPos(window,
                (vidMode.width() - WINDOW_WIDTH) / 2,
                (vidMode.height() - WINDOW_HEIGHT) / 2);

        // 设置键盘回调
        GLFW.glfwSetKeyCallback(window, (wnd, key, scancode, action, mods) -> {
            if (key == GLFW.GLFW_KEY_ESCAPE && action == GLFW.GLFW_RELEASE) running = false;
            if (key == GLFW.GLFW_KEY_SPACE && action == GLFW.GLFW_RELEASE) {
                testCase = (testCase + 1) % 6; // 支持 0..5 共 6 个用例
                setupTestCase();
            }
            if (key == GLFW.GLFW_KEY_G && action == GLFW.GLFW_RELEASE) {
                gravityEnabled = !gravityEnabled;
                physics.setGravity(gravityEnabled ? new Vector2f(0, -98.0f) : new Vector2f(0, 0));
                System.out.println("Gravity " + (gravityEnabled ? "ENABLED" : "DISABLED"));
            }
            if (key == GLFW.GLFW_KEY_S && action == GLFW.GLFW_RELEASE) {
                springsEnabled = !springsEnabled;
                toggleSprings(springsEnabled);
                System.out.println("Springs " + (springsEnabled ? "ENABLED" : "DISABLED"));
            }
            if (key == GLFW.GLFW_KEY_R && action == GLFW.GLFW_RELEASE) {
                resetPhysics();
            }
            if (key == GLFW.GLFW_KEY_C && action == GLFW.GLFW_RELEASE) {
                applyRandomForce();
            }
        });

        GLFW.glfwSetWindowSizeCallback(window, (wnd, w, h) -> ModelRender.setViewport(w, h));

        GLFW.glfwMakeContextCurrent(window);
        GLFW.glfwSwapInterval(1);
        GLFW.glfwShowWindow(window);

        GL.createCapabilities();

        createPhysicsModel();
        ModelRender.initialize();

        System.out.println("Physics System Demo Initialized");
        printControls();
    }

    private void printControls() {
        System.out.println("\n=== Controls ===");
        System.out.println("ESC - Exit");
        System.out.println("SPACE - Change test case");
        System.out.println("G - Toggle gravity");
        System.out.println("S - Toggle springs");
        System.out.println("R - Reset physics");
        System.out.println("C - Apply random force");
        System.out.println("================\n");
    }

    /**
     * 创建物理测试模型
     */
    private void createPhysicsModel() {
        physicsModel = new Model2D("PhysicsDemo");
        physics = physicsModel.getPhysics();

        // 配置物理系统
        physics.setGravity(new Vector2f(0, -98.0f));
        physics.setAirResistance(0.05f);
        physics.setTimeScale(1.0f);
        physics.setEnabled(true);
        physics.initialize();

        setupTestCase();
    }

    /**
     * 设置不同的测试用例
     */
    private void setupTestCase() {
        // 清理之前的设置
        clearCurrentParts();
        physics.reset();

        switch (testCase) {
            case 0:
                setupSpringChain();
                break;
            case 1:
                setupClothSimulation();
                break;
            case 2:
                setupPendulum();
                break;
            case 3:
                setupSoftBody();
                break;
            case 4:
                setupWindTest();
                break;
            case 5:
                setupFreeFallTest();
                break;
        }

        System.out.println("Test Case " + testCase + ": " + getTestCaseName(testCase));
    }

    /**
     * 清理当前部件
     */
    private void clearCurrentParts() {
        // 由于无法直接清除模型的parts列表，我们创建一个新模型
        physicsModel = new Model2D("PhysicsDemo");
        currentParts.clear();

        // 重新配置物理系统
        physics = physicsModel.getPhysics();
        physics.setGravity(new Vector2f(0, -98.0f));
        physics.setAirResistance(0.05f);
        physics.setTimeScale(1.0f);
        physics.setEnabled(true);
        physics.initialize();
    }

    /**
     * 测试用例1: 弹簧链
     */
    private void setupSpringChain() {
        // 创建5个连接的粒子，基于 initialOrigin（因此首个粒子是 (0,0)）
        for (int i = 0; i < 5; i++) {
            Vector2f position = new Vector2f(initialOrigin.x + i * 60, initialOrigin.y + i * 20);
            PhysicsSystem.PhysicsParticle particle = physics.addParticle("particle_" + i, position, 1.0f);

            // 第一个粒子固定（位于 initialOrigin）
            if (i == 0) {
                particle.setMovable(false);
            }

            // 创建对应的模型部件
            ModelPart part = physicsModel.createPart("part_" + i);
            part.setPosition(position.x, position.y);
            currentParts.add(part);

            // 创建圆形网格
            Mesh2D circleMesh = createCircleMesh("circle_" + i, 20, getColorForIndex(i));
            part.addMesh(circleMesh);
            physicsModel.addMesh(circleMesh);

            // 将部件设置为粒子的用户数据，用于同步位置
            particle.setUserData(part);

            // 添加弹簧连接（除了第一个粒子）
            if (i > 0) {
                PhysicsSystem.PhysicsParticle prevParticle = physics.getParticle("particle_" + (i - 1));
                physics.addSpring("spring_" + (i - 1), prevParticle, particle, 60.0f, 0.3f, 0.1f);
            }
        }
    }

    /**
     * 测试用例2: 布料模拟
     */
    private void setupClothSimulation() {
        int rows = 4;
        int cols = 6;
        float spacing = 40.0f;

        // 创建布料网格，基于 initialOrigin
        for (int y = 0; y < rows; y++) {
            for (int x = 0; x < cols; x++) {
                int index = y * cols + x;
                Vector2f position = new Vector2f(initialOrigin.x + x * spacing, initialOrigin.y + y * spacing);

                PhysicsSystem.PhysicsParticle particle = physics.addParticle("cloth_" + index, position, 0.8f);

                // 固定顶部行的粒子（y==0）
                if (y == 0) {
                    particle.setMovable(false);
                }

                ModelPart part = physicsModel.createPart("cloth_part_" + index);
                part.setPosition(position.x, position.y);
                currentParts.add(part);

                Mesh2D squareMesh = createSquareMesh("square_" + index, 15, getColorForIndex(index));
                part.addMesh(squareMesh);
                physicsModel.addMesh(squareMesh);

                // 将部件设置为粒子的用户数据
                particle.setUserData(part);

                // 添加水平弹簧连接
                if (x > 0) {
                    PhysicsSystem.PhysicsParticle leftParticle = physics.getParticle("cloth_" + (index - 1));
                    physics.addSpring("h_spring_" + index, leftParticle, particle, spacing, 0.4f, 0.05f);
                }

                // 添加垂直弹簧连接
                if (y > 0) {
                    PhysicsSystem.PhysicsParticle topParticle = physics.getParticle("cloth_" + (index - cols));
                    physics.addSpring("v_spring_" + index, topParticle, particle, spacing, 0.4f, 0.05f);
                }
            }
        }
    }

    /**
     * 测试用例3: 钟摆系统
     */
    private void setupPendulum() {
        // 创建钟摆锚点（位于 initialOrigin）
        Vector2f anchorPos = new Vector2f(initialOrigin);
        PhysicsSystem.PhysicsParticle anchor = physics.addParticle("anchor", anchorPos, 0.0f);
        anchor.setMovable(false); // 固定锚点

        // 创建钟摆摆锤（相对锚点水平分布）
        for (int i = 0; i < 3; i++) {
            Vector2f pendulumPos = new Vector2f(initialOrigin.x + (i - 1) * 120, initialOrigin.y + 200);
            PhysicsSystem.PhysicsParticle particle = physics.addParticle("pendulum_" + i, pendulumPos, 2.0f);

            // 检查粒子是否成功创建
            if (particle == null) {
                System.err.println("Failed to create pendulum particle: pendulum_" + i);
                continue;
            }

            ModelPart part = physicsModel.createPart("pendulum_part_" + i);
            part.setPosition(pendulumPos.x, pendulumPos.y);
            currentParts.add(part);

            Mesh2D ballMesh = createCircleMesh("ball_" + i, 25, getColorForIndex(i));
            part.addMesh(ballMesh);
            physicsModel.addMesh(ballMesh);

            // 将部件设置为粒子的用户数据
            particle.setUserData(part);

            // 连接到锚点 - 确保anchor和particle都不为null
            if (anchor != null && particle != null) {
                float length = 200 + i * 50;
                physics.addSpring("pendulum_spring_" + i, anchor, particle, length, 0.1f, 0.02f);
            }
        }
    }

    /**
     * 测试用例4: 软体模拟
     */
    private void setupSoftBody() {
        // 创建软体圆形，中心在 initialOrigin
        int points = 8;
        float radius = 60.0f;
        Vector2f center = new Vector2f(initialOrigin);

        // 第一步：先创建所有粒子
        List<PhysicsSystem.PhysicsParticle> particlesList = new ArrayList<>();
        for (int i = 0; i < points; i++) {
            float angle = (float) (i * 2 * Math.PI / points);
            Vector2f position = new Vector2f(
                    center.x + radius * (float) Math.cos(angle),
                    center.y + radius * (float) Math.sin(angle)
            );

            PhysicsSystem.PhysicsParticle particle = physics.addParticle("soft_" + i, position, 0.5f);
            particlesList.add(particle);

            ModelPart part = physicsModel.createPart("soft_part_" + i);
            part.setPosition(position.x, position.y);
            currentParts.add(part);

            Mesh2D pointMesh = createCircleMesh("point_" + i, 12, 0xFF00FFFF);
            part.addMesh(pointMesh);
            physicsModel.addMesh(pointMesh);

            // 将部件设置为粒子的用户数据
            particle.setUserData(part);
        }

        // 第二步：再创建所有弹簧连接
        for (int i = 0; i < points; i++) {
            PhysicsSystem.PhysicsParticle particle = particlesList.get(i);

            // 连接到相邻点
            int next = (i + 1) % points;
            PhysicsSystem.PhysicsParticle nextParticle = particlesList.get(next);
            physics.addSpring("soft_spring_" + i, particle, nextParticle,
                    radius * 2 * (float) Math.sin(Math.PI / points), 0.5f, 0.1f);

            // 连接到对面的点（增加稳定性）
            if (i < points / 2) {
                int opposite = (i + points / 2) % points;
                PhysicsSystem.PhysicsParticle oppositeParticle = particlesList.get(opposite);
                physics.addSpring("cross_spring_" + i, particle, oppositeParticle,
                        radius * 2, 0.2f, 0.05f);
            }
        }
    }

    /**
     * 测试用例5: 自由落体测试
     */
    private void setupFreeFallTest() {
        // 创建地面（位于 initialOrigin）
        Vector2f groundPos = new Vector2f(initialOrigin);
        PhysicsSystem.PhysicsParticle ground = physics.addParticle("ground", groundPos, 0.0f);
        ground.setMovable(false);

        // 创建多个不同质量的物体从不同高度掉落（相对于 initialOrigin）
        for (int i = 0; i < 5; i++) {
            Vector2f position = new Vector2f(initialOrigin.x + 300 + i * 100, initialOrigin.y + 600 - i * 50);
            float mass = 1.0f + i * 0.5f; // 不同质量

            PhysicsSystem.PhysicsParticle particle = physics.addParticle("fall_" + i, position, mass);

            ModelPart part = physicsModel.createPart("fall_part_" + i);
            part.setPosition(position.x, position.y);
            currentParts.add(part);

            Mesh2D ballMesh = createCircleMesh("fall_ball_" + i, 15 + i * 3, getColorForIndex(i));
            part.addMesh(ballMesh);
            physicsModel.addMesh(ballMesh);

            particle.setUserData(part);
        }

        // 添加地面碰撞体（基于 initialOrigin）
        physics.addRectangleCollider("ground_collider", groundPos, 800, 20);
    }

    /**
     * 测试用例6: 风力测试
     */
    private void setupWindTest() {
        // 创建布料用于测试风力，基于 initialOrigin
        int rows = 6;
        int cols = 8;
        float spacing = 35.0f;

        for (int y = 0; y < rows; y++) {
            for (int x = 0; x < cols; x++) {
                int index = y * cols + x;
                // 布料放在 initialOrigin.x + ..., initialOrigin.y - y*spacing + 500 以方便显示
                Vector2f position = new Vector2f(initialOrigin.x + x * spacing, initialOrigin.y - y * spacing + 500);

                PhysicsSystem.PhysicsParticle particle = physics.addParticle("wind_cloth_" + index, position, 0.6f);

                // 固定顶部行的粒子（y==0）
                if (y == 0) {
                    particle.setMovable(false);
                }

                ModelPart part = physicsModel.createPart("wind_part_" + index);
                part.setPosition(position.x, position.y);
                currentParts.add(part);

                Mesh2D squareMesh = createSquareMesh("wind_square_" + index, 12, getColorForIndex(index));
                part.addMesh(squareMesh);
                physicsModel.addMesh(squareMesh);

                particle.setUserData(part);

                // 添加水平弹簧连接
                if (x > 0) {
                    PhysicsSystem.PhysicsParticle leftParticle = physics.getParticle("wind_cloth_" + (index - 1));
                    physics.addSpring("wind_h_spring_" + index, leftParticle, particle, spacing, 0.3f, 0.05f);
                }

                // 添加垂直弹簧连接
                if (y > 0) {
                    PhysicsSystem.PhysicsParticle topParticle = physics.getParticle("wind_cloth_" + (index - cols));
                    physics.addSpring("wind_v_spring_" + index, topParticle, particle, spacing, 0.3f, 0.05f);
                }
            }
        }
    }

    /**
     * 应用风力效果
     */
    private void applyWindEffect() {
        // 随机风力方向
        float windStrength = 50.0f;
        float windDirection = (float) (Math.random() * 2 * Math.PI); // 随机方向

        Vector2f windForce = new Vector2f(
                (float) Math.cos(windDirection) * windStrength,
                (float) Math.sin(windDirection) * windStrength
        );

        // 对所有可移动粒子应用风力
        for (PhysicsSystem.PhysicsParticle particle : physics.getParticles().values()) {
            if (particle.isMovable()) {
                // 风力随粒子高度变化（模拟真实风）
                float heightFactor = particle.getPosition().y / 500.0f;
                Vector2f adjustedWind = new Vector2f(windForce).mul(heightFactor);
                particle.addForce(adjustedWind);
            }
        }

        System.out.println("Wind applied: " + windForce);
    }

    /**
     * 应用持续风力（周期性）
     */
    private void applyContinuousWind(float deltaTime) {
        // 模拟周期性风力
        float time = System.nanoTime() * 0.000000001f;
        float windStrength = 30.0f + (float) Math.sin(time * 2) * 20.0f; // 周期性变化

        Vector2f windForce = new Vector2f(windStrength, 0); // 主要水平方向

        for (PhysicsSystem.PhysicsParticle particle : physics.getParticles().values()) {
            if (particle.isMovable()) {
                particle.addForce(new Vector2f(windForce));
            }
        }
    }

    /**
     * 创建圆形网格 - 修正版本
     */
    private Mesh2D createCircleMesh(String name, float radius, int color) {
        int segments = 16;
        int vertexCount = segments + 1; // 中心点 + 圆周点
        float[] vertices = new float[vertexCount * 2];
        float[] uvs = new float[vertexCount * 2];
        int[] indices = new int[segments * 3];

        // 中心点 (索引0)
        vertices[0] = 0;
        vertices[1] = 0;
        uvs[0] = 0.5f;
        uvs[1] = 0.5f;

        // 圆周点 (索引1到segments)
        for (int i = 0; i < segments; i++) {
            float angle = (float) (i * 2 * Math.PI / segments);
            int vertexIndex = (i + 1) * 2;
            vertices[vertexIndex] = radius * (float) Math.cos(angle);
            vertices[vertexIndex + 1] = radius * (float) Math.sin(angle);
            uvs[vertexIndex] = (float) Math.cos(angle) * 0.5f + 0.5f;
            uvs[vertexIndex + 1] = (float) Math.sin(angle) * 0.5f + 0.5f;
        }

        // 三角形索引 - 每个三角形连接中心点和两个相邻的圆周点
        for (int i = 0; i < segments; i++) {
            int triangleIndex = i * 3;
            indices[triangleIndex] = 0; // 中心点
            indices[triangleIndex + 1] = i + 1; // 当前圆周点
            indices[triangleIndex + 2] = (i + 1) % segments + 1; // 下一个圆周点
        }

        Mesh2D mesh = new Mesh2D(name, vertices, uvs, indices);
        mesh.setTexture(createSolidColorTexture(name + "_tex", color));
        return mesh;
    }

    /**
     * 创建方形网格
     */
    private Mesh2D createSquareMesh(String name, float size, int color) {
        float halfSize = size / 2;
        float[] vertices = {
                -halfSize, -halfSize,
                halfSize, -halfSize,
                halfSize, halfSize,
                -halfSize, halfSize
        };
        float[] uvs = {
                0, 0,
                1, 0,
                1, 1,
                0, 1
        };
        int[] indices = {0, 1, 2, 0, 2, 3};

        Mesh2D mesh = new Mesh2D(name, vertices, uvs, indices);
        mesh.setTexture(createSolidColorTexture(name + "_tex", color));
        return mesh;
    }

    /**
     * 创建纯色纹理
     */
    private Texture createSolidColorTexture(String name, int color) {
        int width = 64, height = 64;
        ByteBuffer buf = MemoryUtil.memAlloc(width * height * 4);

        byte r = (byte) ((color >> 16) & 0xFF);
        byte g = (byte) ((color >> 8) & 0xFF);
        byte b = (byte) (color & 0xFF);

        for (int i = 0; i < width * height; i++) {
            buf.put(r).put(g).put(b).put((byte) 255);
        }

        buf.flip();
        Texture texture = new Texture(name, width, height, Texture.TextureFormat.RGBA, buf);
        MemoryUtil.memFree(buf);
        return texture;
    }

    /**
     * 根据索引获取不同颜色
     */
    private int getColorForIndex(int index) {
        int[] colors = {
                0xFF00FF00, // 绿色
                0xFFFF0000, // 红色
                0xFF0000FF, // 蓝色
                0xFFFFFF00, // 黄色
                0xFFFF00FF, // 紫色
                0xFF00FFFF  // 青色
        };
        return colors[index % colors.length];
    }

    /**
     * 获取测试用例名称
     */
    private String getTestCaseName(int testCase) {
        switch (testCase) {
            case 0: return "Spring Chain";
            case 1: return "Cloth Simulation";
            case 2: return "Pendulum System";
            case 3: return "Soft Body";
            case 4: return "Wind Test";
            case 5: return "Free Fall Test";
            default: return "Unknown";
        }
    }

    /**
     * 切换弹簧状态
     */
    private void toggleSprings(boolean enabled) {
        for (PhysicsSystem.PhysicsSpring spring : physics.getSprings()) {
            spring.setEnabled(enabled);
        }
    }

    /**
     * 重置物理系统
     */
    private void resetPhysics() {
        setupTestCase();
        System.out.println("Physics reset");
    }

    /**
     * 施加随机力
     */
    private void applyRandomForce() {
        for (PhysicsSystem.PhysicsParticle particle : physics.getParticles().values()) {
            if (particle.isMovable()) {
                float forceX = (float) (Math.random() - 0.5) * 200f;
                float forceY = (float) (Math.random() - 0.5) * 200f;
                particle.addForce(new Vector2f(forceX, forceY));
            }
        }
        System.out.println("Random forces applied");
    }

    private void loop() {
        long last = System.nanoTime();
        double nsPerUpdate = 1_000_000_000.0 / 60.0;
        double accumulator = 0.0;

        while (running && !GLFW.glfwWindowShouldClose(window)) {
            long now = System.nanoTime();
            accumulator += (now - last) / nsPerUpdate;
            last = now;

            while (accumulator >= 1.0) {
                update(1.0f / 60.0f);
                accumulator -= 1.0;
            }

            render(last);

            GLFW.glfwSwapBuffers(window);
            GLFW.glfwPollEvents();
        }
    }

    private void update(float dt) {
        // 更新物理系统 - 会自动同步到模型部件
        physicsModel.update(dt);
    }

    private void render(long last) {
        RenderSystem.setClearColor(0.1f, 0.1f, 0.15f, 1.0f);
        ModelRender.render(last, physicsModel);
    }

    private void cleanup() {
        System.out.println("Cleaning up physics demo resources...");
        ModelRender.cleanup();
        Texture.cleanupAll();
        if (window != MemoryUtil.NULL) GLFW.glfwDestroyWindow(window);
        GLFW.glfwTerminate();
        GLFW.glfwSetErrorCallback(null).free();
        System.out.println("Physics demo finished");
    }
}