dramaling-vocab-learning/frontend/lib/services/speechAssessment.ts

import { API_CONFIG } from '@/lib/config/api'

export interface PronunciationScores {
  overall: number
  accuracy: number
  fluency: number
  completeness: number
  prosody: number
}

export interface WordLevelResult {
  word: string
  accuracyScore: number
  errorType: string
  suggestion?: string
}

export interface PronunciationResult {
  assessmentId: string
  flashcardId: string
  referenceText: string
  transcribedText: string
  scores: PronunciationScores
  wordLevelResults: WordLevelResult[]
  feedback: string[]
  confidenceLevel: number
  processingTime: number
  createdAt: string
}

export interface SpeechAssessmentResponse {
  success: boolean
  data?: PronunciationResult
  error?: string
  message?: string
}

export interface SpeechServiceStatus {
  isAvailable: boolean
  serviceName: string
  checkTime: string
  message: string
}

class SpeechAssessmentService {
  private readonly baseUrl: string

  constructor() {
    this.baseUrl = API_CONFIG.BASE_URL
  }

  async evaluatePronunciation(
    audioBlob: Blob,
    referenceText: string,
    flashcardId: string,
    language: string = 'en-US'
  ): Promise<SpeechAssessmentResponse> {
    try {
      // 準備 FormData
      const formData = new FormData()
      formData.append('audio', audioBlob, 'recording.webm')
      formData.append('referenceText', referenceText)
      formData.append('flashcardId', flashcardId)
      formData.append('language', language)

      console.log('🎤 發送發音評估請求:', {
        flashcardId,
        referenceText: referenceText.substring(0, 50) + '...',
        audioSize: `${(audioBlob.size / 1024).toFixed(1)} KB`,
        language
      })

      const response = await fetch(`${this.baseUrl}/api/speech/pronunciation-assessment`, {
        method: 'POST',
        body: formData
      })

      if (!response.ok) {
        const errorData = await response.json().catch(() => ({}))
        throw new Error(errorData.message || `HTTP ${response.status}: ${response.statusText}`)
      }

      const result: SpeechAssessmentResponse = await response.json()

      if (!result.success) {
        throw new Error(result.message || result.error || '發音評估失敗')
      }

      console.log('✅ 發音評估完成:', {
        overallScore: result.data?.scores.overall,
        confidenceLevel: result.data?.confidenceLevel,
        processingTime: `${result.data?.processingTime}ms`
      })

      return result

    } catch (error) {
      console.error('❌ 發音評估錯誤:', error)

      const errorMessage = error instanceof Error ? error.message : '發音評估失敗'

      return {
        success: false,
        error: errorMessage,
        message: this.getErrorMessage(errorMessage)
      }
    }
  }

  async checkServiceStatus(): Promise<SpeechServiceStatus> {
    try {
      const response = await fetch(`${this.baseUrl}/api/speech/service-status`)

      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`)
      }

      const result = await response.json()

      return result.success ? result.data : {
        isAvailable: false,
        serviceName: 'Azure Speech Services',
        checkTime: new Date().toISOString(),
        message: '服務狀態檢查失敗'
      }

    } catch (error) {
      console.error('語音服務狀態檢查失敗:', error)

      return {
        isAvailable: false,
        serviceName: 'Azure Speech Services',
        checkTime: new Date().toISOString(),
        message: error instanceof Error ? error.message : '無法連接到語音服務'
      }
    }
  }

  private getErrorMessage(error: string): string {
    // 將技術錯誤訊息轉換為用戶友善的中文訊息
    if (error.includes('AUDIO_TOO_SHORT')) {
      return '錄音時間太短，請至少錄製 1 秒鐘'
    }
    if (error.includes('AUDIO_TOO_LARGE')) {
      return '音頻檔案過大，請縮短錄音時間'
    }
    if (error.includes('INVALID_AUDIO_FORMAT')) {
      return '音頻格式不支援，請重新錄製'
    }
    if (error.includes('NO_SPEECH_DETECTED')) {
      return '未檢測到語音，請確保麥克風正常並大聲說話'
    }
    if (error.includes('SPEECH_SERVICE_ERROR')) {
      return '語音識別服務暫時不可用，請稍後再試'
    }
    if (error.includes('NetworkError') || error.includes('fetch')) {
      return '網路連接錯誤，請檢查網路連接'
    }

    return '發音評估過程中發生錯誤，請稍後再試'
  }

  // 輔助方法：檢查瀏覽器是否支援錄音
  isRecordingSupported(): boolean {
    return !!(navigator.mediaDevices && navigator.mediaDevices.getUserMedia)
  }

  // 輔助方法：請求麥克風權限
  async requestMicrophonePermission(): Promise<boolean> {
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ audio: true })
      // 立即停止，只是檢查權限
      stream.getTracks().forEach(track => track.stop())
      return true
    } catch (error) {
      console.warn('麥克風權限請求失敗:', error)
      return false
    }
  }
}

// 導出單例實例
export const speechAssessmentService = new SpeechAssessmentService()

// 導出類型供其他組件使用
export type {
  PronunciationResult,
  PronunciationScores,
  WordLevelResult,
  SpeechAssessmentResponse,
  SpeechServiceStatus
}