import {
  Scene,
  OrthographicCamera,
  WebGLRenderer,
  PlaneGeometry,
  Mesh,
  ShaderMaterial,
  Vector3,
  Vector2,
  Clock,
} from 'three'

const vertexShader = `
precision highp float;

void main() {
  gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`

const fragmentShader = `
precision highp float;

uniform float iTime;
uniform vec3  iResolution;
uniform float animationSpeed;

uniform bool enableTop;
uniform bool enableMiddle;
uniform bool enableBottom;

uniform int topLineCount;
uniform int middleLineCount;
uniform int bottomLineCount;

uniform float topLineDistance;
uniform float middleLineDistance;
uniform float bottomLineDistance;

uniform vec3 topWavePosition;
uniform vec3 middleWavePosition;
uniform vec3 bottomWavePosition;

uniform vec2 iMouse;
uniform bool interactive;
uniform float bendRadius;
uniform float bendStrength;
uniform float bendInfluence;

uniform bool parallax;
uniform float parallaxStrength;
uniform vec2 parallaxOffset;

uniform vec3 lineGradient[8];
uniform int lineGradientCount;

const vec3 BLACK = vec3(0.0);
const vec3 PINK  = vec3(233.0, 71.0, 245.0) / 255.0;
const vec3 BLUE  = vec3(47.0,  75.0, 162.0) / 255.0;

mat2 rotate(float r) {
  return mat2(cos(r), sin(r), -sin(r), cos(r));
}

vec3 background_color(vec2 uv) {
  vec3 col = vec3(0.0);

  float y = sin(uv.x - 0.2) * 0.3 - 0.1;
  float m = uv.y - y;

  col += mix(BLUE, BLACK, smoothstep(0.0, 1.0, abs(m)));
  col += mix(PINK, BLACK, smoothstep(0.0, 1.0, abs(m - 0.8)));
  return col * 0.5;
}

vec3 getLineColor(float t, vec3 baseColor) {
  if (lineGradientCount <= 0) {
    return baseColor;
  }

  vec3 gradientColor;

  if (lineGradientCount == 1) {
    gradientColor = lineGradient[0];
  } else {
    float clampedT = clamp(t, 0.0, 0.9999);
    float scaled = clampedT * float(lineGradientCount - 1);
    int idx = int(floor(scaled));
    float f = fract(scaled);
    int idx2 = min(idx + 1, lineGradientCount - 1);

    vec3 c1 = lineGradient[idx];
    vec3 c2 = lineGradient[idx2];

    gradientColor = mix(c1, c2, f);
  }

  return gradientColor * 0.5;
}

float wave(vec2 uv, float offset, vec2 screenUv, vec2 mouseUv, bool shouldBend) {
  float time = iTime * animationSpeed;

  float x_offset   = offset;
  float x_movement = time * 0.1;
  float amp        = sin(offset + time * 0.2) * 0.3;
  float y          = sin(uv.x + x_offset + x_movement) * amp;

  if (shouldBend) {
    vec2 d = screenUv - mouseUv;
    float influence = exp(-dot(d, d) * bendRadius);
    float bendOffset = (mouseUv.y - screenUv.y) * influence * bendStrength * bendInfluence;
    y += bendOffset;
  }

  float m = uv.y - y;
  return 0.0175 / max(abs(m) + 0.01, 1e-3) + 0.01;
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec2 baseUv = (2.0 * fragCoord - iResolution.xy) / iResolution.y;
  baseUv.y *= -1.0;

  if (parallax) {
    baseUv += parallaxOffset;
  }

  vec3 col = vec3(0.0);

  vec3 b = lineGradientCount > 0 ? vec3(0.0) : background_color(baseUv);

  vec2 mouseUv = vec2(0.0);
  if (interactive) {
    mouseUv = (2.0 * iMouse - iResolution.xy) / iResolution.y;
    mouseUv.y *= -1.0;
  }

  if (enableBottom) {
    for (int i = 0; i < bottomLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(bottomLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);

      float angle = bottomWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      col += lineCol * wave(
        ruv + vec2(bottomLineDistance * fi + bottomWavePosition.x, bottomWavePosition.y),
        1.5 + 0.2 * fi,
        baseUv,
        mouseUv,
        interactive
      ) * 0.2;
    }
  }

  if (enableMiddle) {
    for (int i = 0; i < middleLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(middleLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);

      float angle = middleWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      col += lineCol * wave(
        ruv + vec2(middleLineDistance * fi + middleWavePosition.x, middleWavePosition.y),
        2.0 + 0.15 * fi,
        baseUv,
        mouseUv,
        interactive
      );
    }
  }

  if (enableTop) {
    for (int i = 0; i < topLineCount; ++i) {
      float fi = float(i);
      float t = fi / max(float(topLineCount - 1), 1.0);
      vec3 lineCol = getLineColor(t, b);

      float angle = topWavePosition.z * log(length(baseUv) + 1.0);
      vec2 ruv = baseUv * rotate(angle);
      ruv.x *= -1.0;
      col += lineCol * wave(
        ruv + vec2(topLineDistance * fi + topWavePosition.x, topWavePosition.y),
        1.0 + 0.2 * fi,
        baseUv,
        mouseUv,
        interactive
      ) * 0.1;
    }
  }

  fragColor = vec4(col, 1.0);
}

void main() {
  vec4 color = vec4(0.0);
  mainImage(color, gl_FragCoord.xy);
  gl_FragColor = color;
}
`

const MAX_GRADIENT_STOPS = 8

function hexToVec3(hex) {
  let value = hex.trim()

  if (value.startsWith('#')) {
    value = value.slice(1)
  }

  let r = 255
  let g = 255
  let b = 255

  if (value.length === 3) {
    r = parseInt(value[0] + value[0], 16)
    g = parseInt(value[1] + value[1], 16)
    b = parseInt(value[2] + value[2], 16)
  } else if (value.length === 6) {
    r = parseInt(value.slice(0, 2), 16)
    g = parseInt(value.slice(2, 4), 16)
    b = parseInt(value.slice(4, 6), 16)
  }

  return new Vector3(r / 255, g / 255, b / 255)
}

export default class FloatingLines {
  constructor(
    container,
    {
      linesGradient,
      enabledWaves = ['top', 'middle', 'bottom'],
      lineCount = [6],
      lineDistance = [5],
      topWavePosition,
      middleWavePosition,
      bottomWavePosition = { x: 2.0, y: -0.7, rotate: -1 },
      animationSpeed = 1,
      interactive = true,
      bendRadius = 5.0,
      bendStrength = -0.5,
      mouseDamping = 0.05,
      parallax = true,
      parallaxStrength = 0.2,
      mixBlendMode = 'screen',
    } = {},
  ) {
    this.container = container
    this.interactive = interactive
    this.parallax = parallax
    this.mouseDamping = mouseDamping
    this.parallaxStrength = parallaxStrength

    this.targetMouse = new Vector2(-1000, -1000)
    this.currentMouse = new Vector2(-1000, -1000)
    this.targetInfluence = 0
    this.currentInfluence = 0
    this.targetParallax = new Vector2(0, 0)
    this.currentParallax = new Vector2(0, 0)

    const getLineCount = (waveType) => {
      if (typeof lineCount === 'number') return lineCount
      if (!enabledWaves.includes(waveType)) return 0
      const index = enabledWaves.indexOf(waveType)
      return lineCount[index] ?? 6
    }

    const getLineDistance = (waveType) => {
      if (typeof lineDistance === 'number') return lineDistance
      if (!enabledWaves.includes(waveType)) return 0.1
      const index = enabledWaves.indexOf(waveType)
      return lineDistance[index] ?? 0.1
    }

    const topLineCount = enabledWaves.includes('top') ? getLineCount('top') : 0
    const middleLineCount = enabledWaves.includes('middle') ? getLineCount('middle') : 0
    const bottomLineCount = enabledWaves.includes('bottom') ? getLineCount('bottom') : 0

    const topLineDistance = enabledWaves.includes('top') ? getLineDistance('top') * 0.01 : 0.01
    const middleLineDistance = enabledWaves.includes('middle')
      ? getLineDistance('middle') * 0.01
      : 0.01
    const bottomLineDistance = enabledWaves.includes('bottom')
      ? getLineDistance('bottom') * 0.01
      : 0.01

    this.scene = new Scene()
    this.camera = new OrthographicCamera(-1, 1, 1, -1, 0, 1)
    this.camera.position.z = 1

    this.renderer = new WebGLRenderer({ antialias: true, alpha: false })
    this.renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2))
    this.renderer.domElement.style.width = '100%'
    this.renderer.domElement.style.height = '100%'
    this.renderer.domElement.style.mixBlendMode = mixBlendMode
    container.appendChild(this.renderer.domElement)

    this.uniforms = {
      iTime: { value: 0 },
      iResolution: { value: new Vector3(1, 1, 1) },
      animationSpeed: { value: animationSpeed },

      enableTop: { value: enabledWaves.includes('top') },
      enableMiddle: { value: enabledWaves.includes('middle') },
      enableBottom: { value: enabledWaves.includes('bottom') },

      topLineCount: { value: topLineCount },
      middleLineCount: { value: middleLineCount },
      bottomLineCount: { value: bottomLineCount },

      topLineDistance: { value: topLineDistance },
      middleLineDistance: { value: middleLineDistance },
      bottomLineDistance: { value: bottomLineDistance },

      topWavePosition: {
        value: new Vector3(
          topWavePosition?.x ?? 10.0,
          topWavePosition?.y ?? 0.5,
          topWavePosition?.rotate ?? -0.4,
        ),
      },
      middleWavePosition: {
        value: new Vector3(
          middleWavePosition?.x ?? 5.0,
          middleWavePosition?.y ?? 0.0,
          middleWavePosition?.rotate ?? 0.2,
        ),
      },
      bottomWavePosition: {
        value: new Vector3(
          bottomWavePosition?.x ?? 2.0,
          bottomWavePosition?.y ?? -0.7,
          bottomWavePosition?.rotate ?? 0.4,
        ),
      },

      iMouse: { value: new Vector2(-1000, -1000) },
      interactive: { value: interactive },
      bendRadius: { value: bendRadius },
      bendStrength: { value: bendStrength },
      bendInfluence: { value: 0 },

      parallax: { value: parallax },
      parallaxStrength: { value: parallaxStrength },
      parallaxOffset: { value: new Vector2(0, 0) },

      lineGradient: {
        value: Array.from({ length: MAX_GRADIENT_STOPS }, () => new Vector3(1, 1, 1)),
      },
      lineGradientCount: { value: 0 },
    }

    if (linesGradient && linesGradient.length > 0) {
      const stops = linesGradient.slice(0, MAX_GRADIENT_STOPS)
      this.uniforms.lineGradientCount.value = stops.length
      stops.forEach((hex, i) => {
        const color = hexToVec3(hex)
        this.uniforms.lineGradient.value[i].set(color.x, color.y, color.z)
      })
    }

    const material = new ShaderMaterial({
      uniforms: this.uniforms,
      vertexShader,
      fragmentShader,
    })

    const geometry = new PlaneGeometry(2, 2)
    this.mesh = new Mesh(geometry, material)
    this.scene.add(this.mesh)

    this.geometry = geometry
    this.material = material
    this.clock = new Clock()

    this._setSize = () => {
      const width = container.clientWidth || 1
      const height = container.clientHeight || 1
      this.renderer.setSize(width, height, false)
      const canvasWidth = this.renderer.domElement.width
      const canvasHeight = this.renderer.domElement.height
      this.uniforms.iResolution.value.set(canvasWidth, canvasHeight, 1)
    }
    this._setSize()

    this.ro = typeof ResizeObserver !== 'undefined' ? new ResizeObserver(this._setSize) : null
    if (this.ro) this.ro.observe(container)

    this._handlePointerMove = (event) => {
      const rect = this.renderer.domElement.getBoundingClientRect()
      const x = event.clientX - rect.left
      const y = event.clientY - rect.top
      const dpr = this.renderer.getPixelRatio()

      this.targetMouse.set(x * dpr, (rect.height - y) * dpr)
      this.targetInfluence = 1.0

      if (this.parallax) {
        const centerX = rect.width / 2
        const centerY = rect.height / 2
        const offsetX = (x - centerX) / rect.width
        const offsetY = -(y - centerY) / rect.height
        this.targetParallax.set(
          offsetX * this.parallaxStrength,
          offsetY * this.parallaxStrength,
        )
      }
    }

    this._handlePointerLeave = () => {
      this.targetInfluence = 0.0
    }

    this.renderer.domElement.addEventListener('pointermove', this._handlePointerMove)
    this.renderer.domElement.addEventListener('pointerleave', this._handlePointerLeave)

    this.raf = 0
    const renderLoop = () => {
      this.uniforms.iTime.value = this.clock.getElapsedTime()

      if (this.interactive) {
        this.currentMouse.lerp(this.targetMouse, this.mouseDamping)
        this.uniforms.iMouse.value.copy(this.currentMouse)

        this.currentInfluence += (this.targetInfluence - this.currentInfluence) * this.mouseDamping
        this.uniforms.bendInfluence.value = this.currentInfluence
      }

      if (this.parallax) {
        this.currentParallax.lerp(this.targetParallax, this.mouseDamping)
        this.uniforms.parallaxOffset.value.copy(this.currentParallax)
      }

      this.renderer.render(this.scene, this.camera)
      this.raf = requestAnimationFrame(renderLoop)
    }
    renderLoop()
  }

  destroy() {
    cancelAnimationFrame(this.raf)
    if (this.ro) this.ro.disconnect()

    this.renderer.domElement.removeEventListener('pointermove', this._handlePointerMove)
    this.renderer.domElement.removeEventListener('pointerleave', this._handlePointerLeave)

    this.geometry.dispose()
    this.material.dispose()
    this.renderer.dispose()

    if (this.renderer.domElement.parentElement) {
      this.renderer.domElement.parentElement.removeChild(this.renderer.domElement)
    }
  }
}