class ChorusProcessor extends AudioWorkletProcessor {
  constructor() {
    super()

    this.mode = 'chorus'
    this.rate = 0.5
    this.depth = 0.5
    this.feedback = 0
    this.spread = 0.3
    this.bypassed = false

    this.delayBufferSize = Math.floor(sampleRate * 0.05)
    this.delayBufferL = new Float32Array(this.delayBufferSize)
    this.delayBufferR = new Float32Array(this.delayBufferSize)
    this.writeIndex = 0

    this.lfoPhase = 0
    this.lfoPhaseRight = 0

    this.port.onmessage = (event) => {
      const { type, value } = event.data
      switch (type) {
        case 'mode':
          this.mode = value
          break
        case 'frequency':
          this.rate = value
          break
        case 'depth':
          this.depth = value
          break
        case 'feedback':
          this.feedback = value
          break
        case 'spread':
          this.spread = value
          break
        case 'bypass':
          this.bypassed = value
          break
      }
    }
  }

  processChorus(sampleL, sampleR) {
    const baseDelay = 15
    const maxDepth = 8

    this.lfoPhase += this.rate / sampleRate
    this.lfoPhaseRight += this.rate / sampleRate

    if (this.lfoPhase >= 1) this.lfoPhase -= 1
    if (this.lfoPhaseRight >= 1) this.lfoPhaseRight -= 1

    const spreadPhase = this.spread * 0.5
    const lfoL = Math.sin(this.lfoPhase * Math.PI * 2)
    const lfoR = Math.sin((this.lfoPhaseRight + spreadPhase) * Math.PI * 2)

    const delayTimeL = baseDelay + lfoL * maxDepth * this.depth
    const delayTimeR = baseDelay + lfoR * maxDepth * this.depth

    const delaySamplesL = (delayTimeL / 1000) * sampleRate
    const delaySamplesR = (delayTimeR / 1000) * sampleRate

    const readIndexL = (this.writeIndex - delaySamplesL + this.delayBufferSize) % this.delayBufferSize
    const readIndexR = (this.writeIndex - delaySamplesR + this.delayBufferSize) % this.delayBufferSize

    const readIndexL0 = Math.floor(readIndexL) % this.delayBufferSize
    const readIndexL1 = (readIndexL0 + 1) % this.delayBufferSize
    const fracL = readIndexL - Math.floor(readIndexL)

    const readIndexR0 = Math.floor(readIndexR) % this.delayBufferSize
    const readIndexR1 = (readIndexR0 + 1) % this.delayBufferSize
    const fracR = readIndexR - Math.floor(readIndexR)

    const delayedL = this.delayBufferL[readIndexL0] * (1 - fracL) + this.delayBufferL[readIndexL1] * fracL
    const delayedR = this.delayBufferR[readIndexR0] * (1 - fracR) + this.delayBufferR[readIndexR1] * fracR

    this.delayBufferL[this.writeIndex] = sampleL + delayedL * this.feedback
    this.delayBufferR[this.writeIndex] = sampleR + delayedR * this.feedback

    return [delayedL, delayedR]
  }

  processFlanger(sampleL, sampleR) {
    const baseDelay = 1
    const maxDepth = 5

    this.lfoPhase += this.rate / sampleRate
    this.lfoPhaseRight += this.rate / sampleRate

    if (this.lfoPhase >= 1) this.lfoPhase -= 1
    if (this.lfoPhaseRight >= 1) this.lfoPhaseRight -= 1

    const spreadPhase = this.spread * 0.5
    const lfoL = Math.sin(this.lfoPhase * Math.PI * 2)
    const lfoR = Math.sin((this.lfoPhaseRight + spreadPhase) * Math.PI * 2)

    const delayTimeL = baseDelay + lfoL * maxDepth * this.depth
    const delayTimeR = baseDelay + lfoR * maxDepth * this.depth

    const delaySamplesL = (delayTimeL / 1000) * sampleRate
    const delaySamplesR = (delayTimeR / 1000) * sampleRate

    const readIndexL = (this.writeIndex - delaySamplesL + this.delayBufferSize) % this.delayBufferSize
    const readIndexR = (this.writeIndex - delaySamplesR + this.delayBufferSize) % this.delayBufferSize

    const readIndexL0 = Math.floor(readIndexL) % this.delayBufferSize
    const readIndexL1 = (readIndexL0 + 1) % this.delayBufferSize
    const fracL = readIndexL - Math.floor(readIndexL)

    const readIndexR0 = Math.floor(readIndexR) % this.delayBufferSize
    const readIndexR1 = (readIndexR0 + 1) % this.delayBufferSize
    const fracR = readIndexR - Math.floor(readIndexR)

    const delayedL = this.delayBufferL[readIndexL0] * (1 - fracL) + this.delayBufferL[readIndexL1] * fracL
    const delayedR = this.delayBufferR[readIndexR0] * (1 - fracR) + this.delayBufferR[readIndexR1] * fracR

    this.delayBufferL[this.writeIndex] = sampleL + delayedL * this.feedback * 0.9
    this.delayBufferR[this.writeIndex] = sampleR + delayedR * this.feedback * 0.9

    return [delayedL, delayedR]
  }

  process(inputs, outputs) {
    const input = inputs[0]
    const output = outputs[0]

    if (!input || input.length === 0 || !output || output.length === 0) {
      return true
    }

    const inputL = input[0]
    const inputR = input[1] || input[0]
    const outputL = output[0]
    const outputR = output[1] || output[0]

    if (!inputL || !outputL) {
      return true
    }

    for (let i = 0; i < inputL.length; i++) {
      if (this.bypassed) {
        outputL[i] = inputL[i]
        if (outputR) outputR[i] = inputR[i]
        continue
      }

      let processedL, processedR

      if (this.mode === 'flanger') {
        [processedL, processedR] = this.processFlanger(inputL[i], inputR[i])
      } else {
        [processedL, processedR] = this.processChorus(inputL[i], inputR[i])
      }

      outputL[i] = processedL
      if (outputR) outputR[i] = processedR

      this.writeIndex = (this.writeIndex + 1) % this.delayBufferSize
    }

    return true
  }
}

registerProcessor('chorus-processor', ChorusProcessor)