import type { Effect } from './Effect.interface'

export class ReverbEffect implements Effect {
  readonly id = 'reverb'

  private audioContext: AudioContext
  private inputNode: GainNode
  private outputNode: GainNode
  private convolverNode: ConvolverNode
  private wetNode: GainNode
  private dryNode: GainNode

  constructor(audioContext: AudioContext) {
    this.audioContext = audioContext
    this.inputNode = audioContext.createGain()
    this.outputNode = audioContext.createGain()
    this.convolverNode = audioContext.createConvolver()
    this.wetNode = audioContext.createGain()
    this.dryNode = audioContext.createGain()

    this.wetNode.gain.value = 0
    this.dryNode.gain.value = 1

    this.inputNode.connect(this.dryNode)
    this.inputNode.connect(this.convolverNode)
    this.convolverNode.connect(this.wetNode)
    this.dryNode.connect(this.outputNode)
    this.wetNode.connect(this.outputNode)

    this.generateImpulseResponse()
  }

  private generateImpulseResponse(): void {
    const length = this.audioContext.sampleRate * 2
    const impulse = this.audioContext.createBuffer(2, length, this.audioContext.sampleRate)
    const left = impulse.getChannelData(0)
    const right = impulse.getChannelData(1)

    for (let i = 0; i < length; i++) {
      left[i] = (Math.random() * 2 - 1) * Math.pow(1 - i / length, 2)
      right[i] = (Math.random() * 2 - 1) * Math.pow(1 - i / length, 2)
    }

    this.convolverNode.buffer = impulse
  }

  getInputNode(): AudioNode {
    return this.inputNode
  }

  getOutputNode(): AudioNode {
    return this.outputNode
  }

  updateParams(values: Record<string, number>): void {
    if (values.reverbWetDry !== undefined) {
      const wet = values.reverbWetDry / 100
      this.wetNode.gain.value = wet
      this.dryNode.gain.value = 1 - wet
    }
  }

  dispose(): void {
    this.inputNode.disconnect()
    this.outputNode.disconnect()
    this.convolverNode.disconnect()
    this.wetNode.disconnect()
    this.dryNode.disconnect()
  }
}