import { audioRouter } from '../audio/AudioRouter'
import {
  oscilloscope as nativeOscilloscope,
  OSCILLOSCOPE_BUFFER_SIZE,
  isNativeAvailable
} from '../audio/native'
import { getNormalizedOscilloscopeDisplaySamples } from '../audio/native/oscilloscopeDisplaySamples'

export interface OscilloscopeOptions {
  lineColor?: string
  lineWidth?: number
  backgroundColor?: string
  showGrid?: boolean
  gridColor?: string
  pitchLock?: boolean
  underfillEnabled?: boolean
}

const defaultOptions: Required<OscilloscopeOptions> = {
  lineColor: '#00ffff',
  lineWidth: 2,
  backgroundColor: 'transparent',
  showGrid: true,
  gridColor: 'rgba(255, 255, 255, 0.1)',
  pitchLock: true,
  underfillEnabled: false
}

function parseRgbChannels(color: string): string | null {
  const normalized = color.trim()

  if (normalized.startsWith('#')) {
    const hex = normalized.slice(1)
    const expanded = hex.length === 3
      ? hex.split('').map((ch) => `${ch}${ch}`).join('')
      : hex

    if (expanded.length === 6) {
      const r = Number.parseInt(expanded.slice(0, 2), 16)
      const g = Number.parseInt(expanded.slice(2, 4), 16)
      const b = Number.parseInt(expanded.slice(4, 6), 16)
      if (!Number.isNaN(r) && !Number.isNaN(g) && !Number.isNaN(b)) {
        return `${r}, ${g}, ${b}`
      }
    }
  }

  const rgbMatch = /^rgba?\((.*)\)$/i.exec(normalized)
  if (!rgbMatch) return null

  const tokens = rgbMatch[1]
    ?.split(',')
    .map((token) => token.trim())
    .filter(Boolean) ?? []
  if (tokens.length < 3) return null

  const r = Number.parseFloat(tokens[0])
  const g = Number.parseFloat(tokens[1])
  const b = Number.parseFloat(tokens[2])
  if (!Number.isFinite(r) || !Number.isFinite(g) || !Number.isFinite(b)) return null

  return `${Math.max(0, Math.min(255, Math.round(r)))}, ${Math.max(0, Math.min(255, Math.round(g)))}, ${Math.max(0, Math.min(255, Math.round(b)))}`
}

function highContrastUnderfillColor(accentColor: string, alpha: number): string {
  const safeAlpha = Math.max(0, Math.min(1, alpha))
  const channels = parseRgbChannels(accentColor)
  const nearWhite = { r: 245, g: 248, b: 252 }
  const tintAmount = 0.18

  if (!channels) {
    return `rgba(${nearWhite.r}, ${nearWhite.g}, ${nearWhite.b}, ${safeAlpha})`
  }

  const [accentR, accentG, accentB] = channels
    .split(',')
    .map((token) => Number.parseFloat(token.trim()))

  if (!Number.isFinite(accentR) || !Number.isFinite(accentG) || !Number.isFinite(accentB)) {
    return `rgba(${nearWhite.r}, ${nearWhite.g}, ${nearWhite.b}, ${safeAlpha})`
  }

  const mix = (base: number, tint: number): number => Math.round((base * (1 - tintAmount)) + (tint * tintAmount))
  const r = mix(nearWhite.r, accentR)
  const g = mix(nearWhite.g, accentG)
  const b = mix(nearWhite.b, accentB)
  return `rgba(${r}, ${g}, ${b}, ${safeAlpha})`
}

export class Oscilloscope {
  private canvas: HTMLCanvasElement
  private ctx: CanvasRenderingContext2D
  private options: Required<OscilloscopeOptions>
  private animationId: number | null = null
  private isRunning: boolean = false
  private nativeInitialized: boolean = false
  private samplesReceived: number = 0
  private lastSampleRate: number = 0
  private unsubscribeSessionChange: (() => void) | null = null
  private static readonly WARMUP_SAMPLES = 4096 // Need ~4K samples before pitch detection is reliable

  constructor(canvas: HTMLCanvasElement, options: OscilloscopeOptions = {}) {
    this.canvas = canvas
    const ctx = canvas.getContext('2d')
    if (!ctx) throw new Error('Could not get 2D context')
    this.ctx = ctx
    this.options = { ...defaultOptions, ...options }

    // Initialize native module
    this.initNative()
    this.unsubscribeSessionChange = audioRouter.subscribeToSessionChanges(() => {
      this.reset()
    })
  }

  private initNative(): void {
    if (isNativeAvailable() && !this.nativeInitialized) {
      // Initialize with current sample rate, but set lastSampleRate to 0 so
      // updateSampleRateIfNeeded() always fires once the real capture rate is known.
      // This prevents stale-rate issues when capture starts after initialization.
      const sampleRate = audioRouter.getSampleRate()
      this.lastSampleRate = 0
      nativeOscilloscope.setSampleRate(sampleRate)
      nativeOscilloscope.setPitchLock(this.options.pitchLock)
      nativeOscilloscope.setDisplaySamples(getNormalizedOscilloscopeDisplaySamples(sampleRate))
      this.nativeInitialized = true
      console.log(`Oscilloscope: Using native DSP with AudioWorklet (${sampleRate}Hz)`)
    } else if (!isNativeAvailable()) {
      console.error('Oscilloscope: Native DSP not available!')
    }
  }

  // Update sample rate if AudioContext changes (called from draw loop)
  private updateSampleRateIfNeeded(): void {
    if (!isNativeAvailable()) return
    const currentRate = audioRouter.getSampleRate()
    if (currentRate !== this.lastSampleRate && currentRate > 0) {
      this.lastSampleRate = currentRate
      nativeOscilloscope.setSampleRate(currentRate)
      nativeOscilloscope.setDisplaySamples(getNormalizedOscilloscopeDisplaySamples(currentRate))
      console.log(`Oscilloscope: Sample rate updated to ${currentRate}Hz`)
    }
  }

  setOptions(options: Partial<OscilloscopeOptions>): void {
    this.options = { ...this.options, ...options }

    // Update native module settings
    if (isNativeAvailable() && options.pitchLock !== undefined) {
      nativeOscilloscope.setPitchLock(options.pitchLock)
    }
  }

  start(): void {
    if (this.isRunning) return
    this.isRunning = true
    this.draw()
  }

  stop(): void {
    this.isRunning = false
    if (this.animationId !== null) {
      cancelAnimationFrame(this.animationId)
      this.animationId = null
    }
  }

  resize(): void { }

  private draw = (): void => {
    if (!this.isRunning) return

    const { canvas, ctx, options } = this
    const width = canvas.width
    const height = canvas.height
    const dpr = window.devicePixelRatio || 1

    ctx.clearRect(0, 0, width, height)

    if (options.backgroundColor !== 'transparent') {
      ctx.fillStyle = options.backgroundColor
      ctx.fillRect(0, 0, width, height)
    }

    if (options.showGrid) {
      this.drawGrid()
    }

    // Native C++ is being fed continuously by AudioWorklet via AudioEngine
    if (!isNativeAvailable()) {
      console.error('Oscilloscope: Native DSP required')
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    // Check if sample rate needs updating (AudioContext may have initialized after us)
    this.updateSampleRateIfNeeded()

    if (!audioRouter.isCapturing()) {
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    // Flush ALL pending samples to native C++ (prevents sample loss)
    const pendingSamples = audioRouter.flushPendingOscilloscopeSamples()
    for (const chunk of pendingSamples) {
      nativeOscilloscope.pushSamples(chunk)
      this.samplesReceived += chunk.length
    }

    // Skip pitch-locked processing during warmup period.
    // Bypass mode (pitchLock=false) should render immediately using a moving window.
    if (options.pitchLock && this.samplesReceived < Oscilloscope.WARMUP_SAMPLES) {
      // During warmup, just show a static waveform or grid
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    // Process using circular buffer - searches backwards from writePos
    const result = nativeOscilloscope.processContinuous()
    if (!result) {
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    const samplesToShow = result.samplesToShow
    let triggerIndex = result.triggerIndex

    // In bypass mode, ignore trigger locking and follow the live write head.
    // This produces free-running oscilloscope motion without touching pitch-lock behavior.
    if (!options.pitchLock) {
      const writePos = result.writePos
      triggerIndex = writePos - samplesToShow
      while (triggerIndex < 0) triggerIndex += OSCILLOSCOPE_BUFFER_SIZE
    }

    // Get samples from circular buffer for rendering
    const renderData = nativeOscilloscope.getSamples(Math.floor(triggerIndex), samplesToShow)
    if (!renderData || renderData.length === 0) {
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    // Draw waveform (data already starts at trigger point)
    const sliceWidth = width / samplesToShow
    const centerY = height / 2
    const VISUAL_GAIN = 1.8
    const points: Array<{ x: number; y: number }> = []

    for (let i = 0; i < samplesToShow && i < renderData.length; i++) {
      const sample = renderData[i]
      const y = ((1 - sample * VISUAL_GAIN) / 2) * height
      const x = i * sliceWidth
      points.push({ x, y })
    }

    if (points.length < 2) {
      this.animationId = requestAnimationFrame(this.draw)
      return
    }

    if (options.underfillEnabled) {
      ctx.beginPath()
      ctx.moveTo(points[0].x, centerY)
      for (const point of points) {
        ctx.lineTo(point.x, point.y)
      }
      ctx.lineTo(points[points.length - 1].x, centerY)
      ctx.closePath()
      const peakAlpha = 0.28
      const shoulderAlpha = peakAlpha * 0.74
      const centerlineAlpha = 0.09
      const fillGradient = ctx.createLinearGradient(0, 0, 0, height)
      fillGradient.addColorStop(0, highContrastUnderfillColor(options.lineColor, peakAlpha))
      fillGradient.addColorStop(0.44, highContrastUnderfillColor(options.lineColor, peakAlpha * 0.94))
      fillGradient.addColorStop(0.48, highContrastUnderfillColor(options.lineColor, shoulderAlpha))
      fillGradient.addColorStop(0.5, highContrastUnderfillColor(options.lineColor, centerlineAlpha))
      fillGradient.addColorStop(0.52, highContrastUnderfillColor(options.lineColor, shoulderAlpha))
      fillGradient.addColorStop(0.56, highContrastUnderfillColor(options.lineColor, peakAlpha * 0.94))
      fillGradient.addColorStop(1, highContrastUnderfillColor(options.lineColor, peakAlpha))
      ctx.fillStyle = fillGradient
      ctx.fill()
    }

    ctx.lineWidth = options.lineWidth * dpr
    ctx.strokeStyle = options.lineColor
    ctx.lineCap = 'round'
    ctx.lineJoin = 'round'
    ctx.beginPath()
    ctx.moveTo(points[0].x, points[0].y)
    for (let i = 1; i < points.length; i++) {
      ctx.lineTo(points[i].x, points[i].y)
    }
    ctx.stroke()
    this.animationId = requestAnimationFrame(this.draw)
  }

  private drawGrid(): void {
    const { ctx, canvas, options } = this
    const width = canvas.width
    const height = canvas.height
    const dpr = window.devicePixelRatio || 1

    ctx.strokeStyle = options.gridColor
    ctx.lineWidth = dpr

    ctx.beginPath()
    ctx.moveTo(0, height / 2)
    ctx.lineTo(width, height / 2)
    ctx.stroke()

    ctx.beginPath()
    ctx.moveTo(width / 2, 0)
    ctx.lineTo(width / 2, height)
    ctx.stroke()

    ctx.strokeStyle = options.gridColor.replace('0.1', '0.05')
    for (let i = 1; i < 4; i++) {
      if (i === 2) continue
      ctx.beginPath()
      ctx.moveTo(0, (height / 4) * i)
      ctx.lineTo(width, (height / 4) * i)
      ctx.stroke()
      ctx.beginPath()
      ctx.moveTo((width / 4) * i, 0)
      ctx.lineTo((width / 4) * i, height)
      ctx.stroke()
    }
  }

  // Reset state for new track (call on track change to re-enable fast pitch convergence)
  reset(): void {
    // Reset JS warmup state
    this.samplesReceived = 0

    // Reset native state (clears buffers, resets pitch tracking, re-enables fast smoothing)
    if (isNativeAvailable()) {
      nativeOscilloscope.reset()
    }
  }

  dispose(): void {
    this.stop()

    if (this.unsubscribeSessionChange) {
      this.unsubscribeSessionChange()
      this.unsubscribeSessionChange = null
    }

    // Reset native module state
    if (isNativeAvailable()) {
      nativeOscilloscope.reset()
    }

    // Reset warmup state
    this.samplesReceived = 0
    this.lastSampleRate = 0
  }
}