/**
 * Phase: tts — 语音合成（逐句分句生成）
 *
 * 将每个 item 的 script 按标点切分为短句，每句单独生成 TTS 音频。
 * 统一写入 item.segments[]，单句时数组仅 1 个元素。
 * item.audio 指向第一段，item.audioDuration 为累计时长。
 */

const path = require('path')
const { saveManifest, ensureDir, log, getManifestDir, splitTextIntoSentences } = require('./pipeline-utils')

async function phaseTts(manifest, manifestPath, options = {}) {
  const dir = getManifestDir(manifestPath)
  const audioDir = path.join(dir, 'audio')
  ensureDir(audioDir)

  const { synthesize } = require('../qwen-tts')

  const items = manifest.items.filter(it =>
    it.status === 'done' && (it.script || it.text) && !it.audio
  )
  if (items.length === 0) { log('tts', '无待处理 item，跳过'); return }

  log('tts', `共 ${items.length} 段`)

  for (let i = 0; i < items.length; i++) {
    const item = items[i]
    const idx = i + 1
    const fullText = item.script || item.text

    try {
      const sentences = splitTextIntoSentences(fullText)
      const segments = []
      let totalDuration = 0

      for (let j = 0; j < sentences.length; j++) {
        const sentence = sentences[j]
        const segId = `${item.id || idx}_${j + 1}`
        const { filePath, duration } = await synthesize(sentence, {
          outputDir: audioDir,
          id: segId,
          voice: manifest.ttsVoice || undefined,
          instruction: manifest.ttsInstruction || undefined,
          rate: manifest.ttsRate || undefined,
        })
        segments.push({
          text: sentence,
          audio: path.relative(dir, filePath).replace(/\\/g, '/'),
          duration: Math.round(duration * 1000) / 1000,
        })
        totalDuration += duration
      }

      // 统一使用 segments 数组（单句 = 1 元素，多句 = N 元素）
      item.segments = segments
      item.audio = segments[0].audio
      item.audioDuration = Math.round(totalDuration * 1000) / 1000
      log('tts', `[${idx}/${items.length}] ${totalDuration.toFixed(1)}s (${segments.length}句): ${fullText.substring(0, 30)}...`)
    } catch (err) {
      item.status = 'failed'
      item.error = `TTS失败: ${err.message}`
      log('tts', `[${idx}/${items.length}] 失败: ${err.message}`)
    }
    saveManifest(manifestPath, manifest)
  }
}

module.exports = { phaseTts }