"use client";

import { useEffect, useRef, useState } from "react";
import { useTheme } from "next-themes";
import Matter from "matter-js";

/**
 * Antigravity Background Component
 * 使用 Matter.js 实现完整的 Google Antigravity 物理效果
 */
export function AntigravityBackground() {
  const sceneRef = useRef<HTMLDivElement>(null);
  const engineRef = useRef<Matter.Engine | null>(null);
  const renderRef = useRef<Matter.Render | null>(null);
  const mouseConstraintRef = useRef<Matter.MouseConstraint | null>(null);
  const { resolvedTheme } = useTheme();
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    setMounted(true);
  }, []);

  useEffect(() => {
    if (!mounted || !sceneRef.current) return;

    const safeRemoveCanvas = (render: Matter.Render | null) => {
      const canvas = render?.canvas;
      if (canvas?.parentNode) {
        canvas.parentNode.removeChild(canvas);
      }
    };

    // 清理旧实例
    if (engineRef.current) {
      Matter.Engine.clear(engineRef.current);
    }
    if (renderRef.current) {
      Matter.Render.stop(renderRef.current);
      safeRemoveCanvas(renderRef.current);
    }

    // 创建物理引擎
    const engine = Matter.Engine.create({
      gravity: { x: 0, y: 1, scale: 0.001 },
    });
    engineRef.current = engine;

    // 创建渲染器
    const render = Matter.Render.create({
      element: sceneRef.current,
      engine: engine,
      options: {
        width: window.innerWidth,
        height: window.innerHeight,
        wireframes: false,
        background: "transparent",
        pixelRatio: window.devicePixelRatio,
      },
    });
    renderRef.current = render;

    // 创建墙壁（边界）
    const wallOptions: Matter.IBodyDefinition = {
      isStatic: true,
      render: {
        fillStyle: "transparent",
        strokeStyle: "transparent",
      },
      friction: 0.3,
      restitution: 0.6,
    };

    const walls = [
      // 底部
      Matter.Bodies.rectangle(
        window.innerWidth / 2,
        window.innerHeight + 25,
        window.innerWidth,
        50,
        wallOptions
      ),
      // 顶部
      Matter.Bodies.rectangle(
        window.innerWidth / 2,
        -25,
        window.innerWidth,
        50,
        wallOptions
      ),
      // 左侧
      Matter.Bodies.rectangle(
        -25,
        window.innerHeight / 2,
        50,
        window.innerHeight,
        wallOptions
      ),
      // 右侧
      Matter.Bodies.rectangle(
        window.innerWidth + 25,
        window.innerHeight / 2,
        50,
        window.innerHeight,
        wallOptions
      ),
    ];

    Matter.Composite.add(engine.world, walls);

    // 创建可拖动的物体
    const emojis = [
      { emoji: "🤖", x: 200, y: 100, size: 40, color: "#667eea" },
      { emoji: "💬", x: 400, y: 150, size: 35, color: "#764ba2" },
      { emoji: "✨", x: 600, y: 200, size: 38, color: "#f093fb" },
      { emoji: "🚀", x: 800, y: 120, size: 36, color: "#4facfe" },
      { emoji: "🎨", x: 300, y: 400, size: 34, color: "#43e97b" },
      { emoji: "⚡", x: 700, y: 350, size: 37, color: "#fa709a" },
    ];

    const bodies = emojis.map((item) => {
      const body = Matter.Bodies.circle(item.x, item.y, item.size / 2, {
        restitution: 0.8,
        friction: 0.05,
        density: 0.001,
        render: {
          fillStyle: item.color + "40",
          strokeStyle: item.color + "80",
          lineWidth: 2,
        },
      });

      // 存储 emoji 信息到 body 上
      (body as any).emoji = item.emoji;
      (body as any).size = item.size;

      return body;
    });

    Matter.Composite.add(engine.world, bodies);

    // 添加鼠标控制
    const mouse = Matter.Mouse.create(render.canvas);
    const mouseConstraint = Matter.MouseConstraint.create(engine, {
      mouse: mouse,
      constraint: {
        stiffness: 0.2,
        render: {
          visible: false,
        },
      },
    });
    mouseConstraintRef.current = mouseConstraint;

    Matter.Composite.add(engine.world, mouseConstraint);

    // 保持鼠标与渲染器同步
    render.mouse = mouse;

    // 自定义渲染函数（绘制 emoji）
    Matter.Events.on(render, "afterRender", () => {
      const context = render.context;
      
      bodies.forEach((body) => {
        const emoji = (body as any).emoji;
        const size = (body as any).size;
        
        if (!emoji) return;

        context.save();
        context.translate(body.position.x, body.position.y);
        context.rotate(body.angle);
        
        // 绘制半透明背景圆
        context.beginPath();
        context.arc(0, 0, size / 2, 0, Math.PI * 2);
        context.fillStyle = body.render.fillStyle || "#667eea40";
        context.fill();
        
        // 绘制 emoji
        context.font = `${size * 0.8}px Arial`;
        context.textAlign = "center";
        context.textBaseline = "middle";
        context.fillText(emoji, 0, 0);
        
        context.restore();
      });
    });

    // 启动引擎和渲染器
    const runner = Matter.Runner.create();
    Matter.Runner.run(runner, engine);
    Matter.Render.run(render);

    // 窗口大小调整
    const handleResize = () => {
      render.canvas.width = window.innerWidth;
      render.canvas.height = window.innerHeight;
      render.options.width = window.innerWidth;
      render.options.height = window.innerHeight;

      // 更新墙壁位置
      Matter.Body.setPosition(walls[0], {
        x: window.innerWidth / 2,
        y: window.innerHeight + 25,
      });
      Matter.Body.setPosition(walls[1], {
        x: window.innerWidth / 2,
        y: -25,
      });
      Matter.Body.setPosition(walls[2], {
        x: -25,
        y: window.innerHeight / 2,
      });
      Matter.Body.setPosition(walls[3], {
        x: window.innerWidth + 25,
        y: window.innerHeight / 2,
      });

      // 更新墙壁尺寸
      Matter.Body.scale(walls[0], window.innerWidth / walls[0].bounds.max.x, 1);
      Matter.Body.scale(walls[1], window.innerWidth / walls[1].bounds.max.x, 1);
      Matter.Body.scale(walls[2], 1, window.innerHeight / walls[2].bounds.max.y);
      Matter.Body.scale(walls[3], 1, window.innerHeight / walls[3].bounds.max.y);
    };

    window.addEventListener("resize", handleResize);

    // 清理函数
    return () => {
      window.removeEventListener("resize", handleResize);
      
      if (mouseConstraintRef.current) {
        Matter.Composite.remove(engine.world, mouseConstraintRef.current);
        mouseConstraintRef.current = null;
      }
      
      if (renderRef.current) {
        Matter.Render.stop(renderRef.current);
        safeRemoveCanvas(renderRef.current);
        renderRef.current = null;
      }
      
      if (engineRef.current) {
        Matter.Engine.clear(engineRef.current);
        engineRef.current = null;
      }
      
      Matter.Runner.stop(runner);
    };
  }, [mounted, resolvedTheme]);

  if (!mounted) return null;

  return (
    <div
      ref={sceneRef}
      className="fixed inset-0 z-0"
      style={{
        filter: resolvedTheme === "dark" ? "brightness(0.8)" : "brightness(1)",
        transition: "filter 0.5s ease-in-out",
      }}
    />
  );
}