// Audio context, gain nodes, volume/mute management
// This module has ZERO imports from other audio modules to prevent circular deps.

let ctx: AudioContext | null = null
let musicGain: GainNode | null = null
let sfxGain: GainNode | null = null
let musicPlaying = false
let musicTimeout: number | null = null

// AudioContext is ONLY created inside ensureAudioContext() (called from user gesture).
// Before that, all SFX calls silently no-op to avoid Chrome autoplay warnings.
let _audioUnlocked = false

let masterMuted = false
const MUSIC_VOL = 0.12
const SFX_VOL = 0.25

export function initCtx() {
  if (ctx) return
  ctx = new AudioContext()
  musicGain = ctx.createGain()
  musicGain.gain.value = masterMuted ? 0 : 0.12
  musicGain.connect(ctx.destination)
  sfxGain = ctx.createGain()
  sfxGain.gain.value = masterMuted ? 0 : 0.25
  sfxGain.connect(ctx.destination)
}

export function getCtx(): AudioContext {
  if (!ctx) initCtx()
  if (ctx!.state === 'suspended') {
    ctx!.resume().catch(err => console.warn('[Audio] context resume failed:', err))
  }
  return ctx!
}

// Get the SFX destination node (gain is 0 when muted, so audio is silent but context stays valid)
export function getSfxDest(): AudioNode {
  const c = getCtx()
  return sfxGain ?? c.destination
}

export function getMusicGain(): GainNode | null {
  return musicGain
}

export function getSfxGain(): GainNode | null {
  return sfxGain
}

export function isMusicPlaying(): boolean {
  return musicPlaying
}

export function setMusicPlaying(v: boolean) {
  musicPlaying = v
}

export function getMusicTimeout(): number | null {
  return musicTimeout
}

export function setMusicTimeout(v: number | null) {
  musicTimeout = v
}

export function isAudioUnlocked(): boolean {
  return _audioUnlocked
}

export function setAudioUnlocked(v: boolean) {
  _audioUnlocked = v
}

export function isMasterMuted(): boolean {
  return masterMuted
}

export function getMasterMuted(): boolean {
  return masterMuted
}

export function setMusicVolume(v: number) {
  if (musicGain) musicGain.gain.value = Math.max(0, Math.min(1, v))
}

export function setSfxVolume(v: number) {
  if (sfxGain) sfxGain.gain.value = Math.max(0, Math.min(1, v))
}

export function setMasterMute(muted: boolean) {
  masterMuted = muted
  if (muted) {
    if (musicGain) musicGain.gain.value = 0
    if (sfxGain) sfxGain.gain.value = 0
    // Note: kokoroStop and speechSynthesis.cancel are called from the caller
    // to avoid circular deps — see index.ts setMasterMute wrapper
  } else {
    if (musicGain) musicGain.gain.value = MUSIC_VOL
    if (sfxGain) sfxGain.gain.value = SFX_VOL
  }
}

// Disconnect gain nodes to instantly kill all in-flight oscillators/buffers,
// then reconnect so future sounds still work
export function resetGainNodes() {
  if (ctx) {
    if (musicGain) {
      musicGain.disconnect()
      musicGain = ctx.createGain()
      musicGain.gain.value = masterMuted ? 0 : MUSIC_VOL
      musicGain.connect(ctx.destination)
    }
    if (sfxGain) {
      sfxGain.disconnect()
      sfxGain = ctx.createGain()
      sfxGain.gain.value = masterMuted ? 0 : SFX_VOL
      sfxGain.connect(ctx.destination)
    }
  }
}

// Tracked audio timers — SFX fire-and-forget delays that must be cleaned on scene destroy
const _audioTimers = new Set<ReturnType<typeof setTimeout>>()

export function audioTimeout(fn: () => void, ms: number): ReturnType<typeof setTimeout> {
  const id = setTimeout(() => { _audioTimers.delete(id); fn() }, ms)
  _audioTimers.add(id)
  return id
}

export function clearAllAudioTimers() {
  for (const id of _audioTimers) clearTimeout(id)
  _audioTimers.clear()
}

export { MUSIC_VOL, SFX_VOL }