'use client';

import React, { useRef, useEffect, CSSProperties } from 'react';

class Grad {
  x: number;
  y: number;
  z: number;
  constructor(x: number, y: number, z: number) {
    this.x = x;
    this.y = y;
    this.z = z;
  }
  dot2(x: number, y: number): number {
    return this.x * x + this.y * y;
  }
}

class Noise {
  grad3: Grad[];
  p: number[];
  perm: number[];
  gradP: Grad[];

  constructor(seed = 0) {
    this.grad3 = [
      new Grad(1, 1, 0),
      new Grad(-1, 1, 0),
      new Grad(1, -1, 0),
      new Grad(-1, -1, 0),
      new Grad(1, 0, 1),
      new Grad(-1, 0, 1),
      new Grad(1, 0, -1),
      new Grad(-1, 0, -1),
      new Grad(0, 1, 1),
      new Grad(0, -1, 1),
      new Grad(0, 1, -1),
      new Grad(0, -1, -1),
    ];
    this.p = [
      151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240,
      21, 10, 23, 190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88,
      237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83,
      111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25, 63, 161, 1, 216,
      80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186,
      3, 64, 52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58,
      17, 182, 189, 28, 42, 223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
      129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193,
      238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
      184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128,
      195, 78, 66, 215, 61, 156, 180,
    ];
    this.perm = new Array(512);
    this.gradP = new Array(512);
    this.seed(seed);
  }
  seed(seed: number) {
    if (seed > 0 && seed < 1) seed *= 65536;
    seed = Math.floor(seed);
    if (seed < 256) seed |= seed << 8;
    for (let i = 0; i < 256; i++) {
      const v = i & 1 ? this.p[i] ^ (seed & 255) : this.p[i] ^ ((seed >> 8) & 255);
      this.perm[i] = this.perm[i + 256] = v;
      this.gradP[i] = this.gradP[i + 256] = this.grad3[v % 12];
    }
  }
  fade(t: number): number {
    return t * t * t * (t * (t * 6 - 15) + 10);
  }
  lerp(a: number, b: number, t: number): number {
    return (1 - t) * a + t * b;
  }
  perlin2(x: number, y: number): number {
    let X = Math.floor(x),
      Y = Math.floor(y);
    x -= X;
    y -= Y;
    X &= 255;
    Y &= 255;
    const n00 = this.gradP[X + this.perm[Y]].dot2(x, y);
    const n01 = this.gradP[X + this.perm[Y + 1]].dot2(x, y - 1);
    const n10 = this.gradP[X + 1 + this.perm[Y]].dot2(x - 1, y);
    const n11 = this.gradP[X + 1 + this.perm[Y + 1]].dot2(x - 1, y - 1);
    const u = this.fade(x);
    return this.lerp(this.lerp(n00, n10, u), this.lerp(n01, n11, u), this.fade(y));
  }
}

interface Point {
  x: number;
  y: number;
  wave: { x: number; y: number };
  cursor: { x: number; y: number; vx: number; vy: number };
}

interface Mouse {
  x: number;
  y: number;
  lx: number;
  ly: number;
  sx: number;
  sy: number;
  v: number;
  vs: number;
  a: number;
  set: boolean;
}

interface Config {
  lineColor: string;
  waveSpeedX: number;
  waveSpeedY: number;
  waveAmpX: number;
  waveAmpY: number;
  friction: number;
  tension: number;
  maxCursorMove: number;
  xGap: number;
  yGap: number;
}

export interface WavesProps {
  lineColor?: string;
  backgroundColor?: string;
  waveSpeedX?: number;
  waveSpeedY?: number;
  waveAmpX?: number;
  waveAmpY?: number;
  xGap?: number;
  yGap?: number;
  friction?: number;
  tension?: number;
  maxCursorMove?: number;
  style?: CSSProperties;
  className?: string;
  animate?: boolean;
  interactive?: boolean;
}

const Waves: React.FC<WavesProps> = ({
  lineColor = '#fff',
  backgroundColor = 'rgba(255, 255, 255, 0.2)',
  waveSpeedX = 0.0125,
  waveSpeedY = 0.005,
  waveAmpX = 32,
  waveAmpY = 16,
  xGap = 10,
  yGap = 32,
  friction = 0.925,
  tension = 0.005,
  maxCursorMove = 100,
  style = {},
  className = '',
  animate = true,
  interactive = true,
}) => {
  const containerRef = useRef<HTMLDivElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);
  const ctxRef = useRef<CanvasRenderingContext2D | null>(null);
  const boundingRef = useRef({ width: 0, height: 0, left: 0, top: 0 });
  const noiseRef = useRef(new Noise(Math.random()));
  const linesRef = useRef<Point[][]>([]);
  const mouseRef = useRef<Mouse>({
    x: -10,
    y: 0,
    lx: 0,
    ly: 0,
    sx: 0,
    sy: 0,
    v: 0,
    vs: 0,
    a: 0,
    set: false,
  });
  const configRef = useRef<Config>({
    lineColor,
    waveSpeedX,
    waveSpeedY,
    waveAmpX,
    waveAmpY,
    friction,
    tension,
    maxCursorMove,
    xGap,
    yGap,
  });
  const frameIdRef = useRef<number | null>(null);

  useEffect(() => {
    configRef.current = {
      lineColor,
      waveSpeedX,
      waveSpeedY,
      waveAmpX,
      waveAmpY,
      friction,
      tension,
      maxCursorMove,
      xGap,
      yGap,
    };
  }, [
    lineColor,
    waveSpeedX,
    waveSpeedY,
    waveAmpX,
    waveAmpY,
    friction,
    tension,
    maxCursorMove,
    xGap,
    yGap,
  ]);

  useEffect(() => {
    const canvas = canvasRef.current;
    const container = containerRef.current;
    if (!canvas || !container) return;
    ctxRef.current = canvas.getContext('2d');

    function setSize() {
      if (!container) return;
      const rect = container.getBoundingClientRect();
      boundingRef.current = {
        width: rect.width,
        height: rect.height,
        left: rect.left,
        top: rect.top,
      };
      if (canvas) {
        canvas.width = rect.width;
        canvas.height = rect.height;
      }
    }

    function setLines() {
      const { width, height } = boundingRef.current;
      linesRef.current = [];
      const oWidth = width + 200;
      const oHeight = height + 30;
      const { xGap, yGap } = configRef.current;
      const totalLines = Math.ceil(oWidth / xGap);
      const totalPoints = Math.ceil(oHeight / yGap);
      const xStart = (width - xGap * totalLines) / 2;
      const yStart = (height - yGap * totalPoints) / 2;
      for (let i = 0; i <= totalLines; i++) {
        const pts: Point[] = [];
        for (let j = 0; j <= totalPoints; j++) {
          pts.push({
            x: xStart + xGap * i,
            y: yStart + yGap * j,
            wave: { x: 0, y: 0 },
            cursor: { x: 0, y: 0, vx: 0, vy: 0 },
          });
        }
        linesRef.current.push(pts);
      }
    }

    function moved(point: Point, withCursor = true): { x: number; y: number } {
      const x = point.x + point.wave.x + (withCursor ? point.cursor.x : 0);
      const y = point.y + point.wave.y + (withCursor ? point.cursor.y : 0);
      return { x: Math.round(x * 10) / 10, y: Math.round(y * 10) / 10 };
    }

    function drawLines(withCursor = true) {
      const { width, height } = boundingRef.current;
      const ctx = ctxRef.current;
      if (!ctx) return;

      ctx.clearRect(0, 0, width, height);
      ctx.beginPath();
      ctx.strokeStyle = configRef.current.lineColor;

      linesRef.current.forEach(points => {
        let p1 = moved(points[0], false);
        ctx.moveTo(p1.x, p1.y);
        points.forEach((p, idx) => {
          const isLast = idx === points.length - 1;
          p1 = moved(p, withCursor && !isLast);
          const p2 = moved(points[idx + 1] || points[points.length - 1], withCursor && !isLast);
          ctx.lineTo(p1.x, p1.y);
          if (isLast) ctx.moveTo(p2.x, p2.y);
        });
      });

      ctx.stroke();
    }

    function drawStatic() {
      linesRef.current.forEach(pts => {
        pts.forEach(p => {
          p.wave.x = 0;
          p.wave.y = 0;
          p.cursor.x = 0;
          p.cursor.y = 0;
          p.cursor.vx = 0;
          p.cursor.vy = 0;
        });
      });
      drawLines(false);
    }

    function movePoints(time: number) {
      const lines = linesRef.current;
      const mouse = mouseRef.current;
      const noise = noiseRef.current;
      const { waveSpeedX, waveSpeedY, waveAmpX, waveAmpY, friction, tension, maxCursorMove } = configRef.current;

      lines.forEach(pts => {
        pts.forEach(p => {
          const move = noise.perlin2((p.x + time * waveSpeedX) * 0.002, (p.y + time * waveSpeedY) * 0.0015) * 12;
          p.wave.x = Math.cos(move) * waveAmpX;
          p.wave.y = Math.sin(move) * waveAmpY;

          if (!interactive) return;

          const dx = p.x - mouse.sx;
          const dy = p.y - mouse.sy;
          const dist = Math.hypot(dx, dy);
          const l = Math.max(175, mouse.vs);
          if (dist < l) {
            const s = 1 - dist / l;
            const f = Math.cos(dist * 0.001) * s;
            p.cursor.vx += Math.cos(mouse.a) * f * l * mouse.vs * 0.00065;
            p.cursor.vy += Math.sin(mouse.a) * f * l * mouse.vs * 0.00065;
          }

          p.cursor.vx += (0 - p.cursor.x) * tension;
          p.cursor.vy += (0 - p.cursor.y) * tension;
          p.cursor.vx *= friction;
          p.cursor.vy *= friction;
          p.cursor.x += p.cursor.vx * 2;
          p.cursor.y += p.cursor.vy * 2;
          p.cursor.x = Math.min(maxCursorMove, Math.max(-maxCursorMove, p.cursor.x));
          p.cursor.y = Math.min(maxCursorMove, Math.max(-maxCursorMove, p.cursor.y));
        });
      });
    }

    function tick(t: number) {
      const container = containerRef.current;
      if (!container) return;

      if (interactive) {
        const mouse = mouseRef.current;
        mouse.sx += (mouse.x - mouse.sx) * 0.1;
        mouse.sy += (mouse.y - mouse.sy) * 0.1;
        const dx = mouse.x - mouse.lx;
        const dy = mouse.y - mouse.ly;
        const d = Math.hypot(dx, dy);
        mouse.v = d;
        mouse.vs += (d - mouse.vs) * 0.1;
        mouse.vs = Math.min(100, mouse.vs);
        mouse.lx = mouse.x;
        mouse.ly = mouse.y;
        mouse.a = Math.atan2(dy, dx);
        container.style.setProperty('--x', `${mouse.sx}px`);
        container.style.setProperty('--y', `${mouse.sy}px`);
      }

      movePoints(t);
      drawLines(true);
      frameIdRef.current = requestAnimationFrame(tick);
    }

    // NEW: react to parent size changes (content height, header/footer, etc.)
    const ro =
      typeof ResizeObserver !== 'undefined'
        ? new ResizeObserver(() => onResize())
        : null;

    function onResize() {
      setSize();
      setLines();
      if (!animate) drawStatic();
    }

    function updateMouse(x: number, y: number) {
      if (!interactive) return;
      const mouse = mouseRef.current;
      const b = boundingRef.current;
      mouse.x = x - b.left;
      mouse.y = y - b.top;
      if (!mouse.set) {
        mouse.sx = mouse.x;
        mouse.sy = mouse.y;
        mouse.lx = mouse.x;
        mouse.ly = mouse.y;
        mouse.set = true;
      }
    }

    function onMouseMove(e: MouseEvent) {
      updateMouse(e.clientX, e.clientY);
    }

    function onTouchMove(e: TouchEvent) {
      const touch = e.touches[0];
      if (touch) updateMouse(touch.clientX, touch.clientY);
    }

    setSize();
    setLines();

    window.addEventListener('resize', onResize);
    ro?.observe(container);

    if (interactive) {
      window.addEventListener('mousemove', onMouseMove);
      window.addEventListener('touchmove', onTouchMove, { passive: true });
    }

    if (animate) {
      frameIdRef.current = requestAnimationFrame(tick);
    } else {
      drawStatic();
    }

    return () => {
      window.removeEventListener('resize', onResize);
      ro?.disconnect();
      if (interactive) {
        window.removeEventListener('mousemove', onMouseMove);
        window.removeEventListener('touchmove', onTouchMove);
      }
      if (frameIdRef.current !== null) cancelAnimationFrame(frameIdRef.current);
      frameIdRef.current = null;
    };
  }, [animate, interactive]);

  return (
    <div
      ref={containerRef}
      style={{
        backgroundColor,
        ...style,
        position: 'absolute',
        inset: 0,
        width: '100%',
        height: '100%',
        pointerEvents: 'none',
        zIndex: 0,
      }}
      className={`w-full h-full overflow-hidden ${className}`}
    >
      <canvas ref={canvasRef} className="block w-full h-full" />
    </div>
  );
};

export default Waves;
