export const MUSIC_DURATION_MIN = 30
export const MUSIC_DURATION_MAX = 180
export const MUSIC_DURATION_DEFAULT = 60
export const MUSIC_STEPS_MIN = 8
export const MUSIC_STEPS_MAX = 100
export const MUSIC_STEPS_DEFAULT = 50
export const MUSIC_CFG_DEFAULT = 5
export const MUSIC_LYRICS_STRENGTH_DEFAULT = 0.9
export const MUSIC_TAGS_MAX = 2000
export const MUSIC_LYRICS_MAX = 8000

export const MUSIC_STRUCTURE_CHIPS = [
  '[Verse 1]',
  '[Verse 2]',
  '[Pre-Chorus]',
  '[Chorus]',
  '[Bridge]',
  '[Guitar Solo]',
  '[Instrumental]',
  '[Outro]'
] as const

export const DEFAULT_MUSIC_TAGS = 'modern synthpop, 120 bpm, female vocals, punchy bass, analog synths'

export const DEFAULT_MUSIC_LYRICS = `[Verse 1]

[Chorus]

[Guitar Solo]

[Outro]
`

export type MusicEngine = 'ace-step' | 'ace-step-1.5'

export function parseMusicEngine(raw: unknown): MusicEngine {
  const value = String(raw || '').trim().toLowerCase()
  if (value === 'ace-step-1.5' || value === 'ace15' || value === 'v1.5') return 'ace-step-1.5'
  return 'ace-step'
}

export function clampMusicDuration(raw: unknown, fallback = MUSIC_DURATION_DEFAULT) {
  const value = Number(raw)
  if (!Number.isFinite(value)) return fallback
  return Math.min(MUSIC_DURATION_MAX, Math.max(MUSIC_DURATION_MIN, Math.round(value)))
}

export function clampMusicSteps(raw: unknown, fallback = MUSIC_STEPS_DEFAULT) {
  const value = Number(raw)
  if (!Number.isFinite(value)) return fallback
  return Math.min(MUSIC_STEPS_MAX, Math.max(MUSIC_STEPS_MIN, Math.round(value)))
}

export function clampMusicCfg(raw: unknown, fallback = MUSIC_CFG_DEFAULT) {
  const value = Number(raw)
  if (!Number.isFinite(value)) return fallback
  return Math.min(15, Math.max(1, Math.round(value * 10) / 10))
}

export function clampLyricsStrength(raw: unknown, fallback = MUSIC_LYRICS_STRENGTH_DEFAULT) {
  const value = Number(raw)
  if (!Number.isFinite(value)) return fallback
  return Math.min(2, Math.max(0, Math.round(value * 100) / 100))
}

export function sanitizeMusicTags(raw: unknown) {
  return String(raw || '').replace(/\r\n/g, '\n').trim().slice(0, MUSIC_TAGS_MAX)
}

export function sanitizeMusicLyrics(raw: unknown, instrumental = false) {
  if (instrumental) return ''
  return String(raw || '').replace(/\r\n/g, '\n').trim().slice(0, MUSIC_LYRICS_MAX)
}

export function parseMusicSeed(raw: unknown) {
  const text = String(raw ?? '').trim().toLowerCase()
  if (!text || text === 'random') return Math.floor(Math.random() * 2_147_483_647)
  const value = Number(text)
  if (!Number.isFinite(value)) return Math.floor(Math.random() * 2_147_483_647)
  return Math.max(0, Math.min(2_147_483_647, Math.floor(value)))
}

export function musicContentType(ext: string) {
  const kind = String(ext || '').replace(/^\./, '').toLowerCase()
  if (kind === 'wav') return 'audio/wav'
  if (kind === 'flac') return 'audio/flac'
  if (kind === 'mp3') return 'audio/mpeg'
  if (kind === 'ogg' || kind === 'opus') return 'audio/ogg'
  return 'application/octet-stream'
}

export function musicExtension(filename: string) {
  const match = String(filename || '').toLowerCase().match(/\.(wav|flac|mp3|ogg|opus)$/)
  return match ? match[1] : 'flac'
}