# Voice Clone Capability Specification

## ADDED Requirements

### Requirement: Provider Abstraction Layer
The system SHALL provide a unified provider abstraction layer for voice cloning services, supporting multiple vendors through a common interface.

#### Scenario: Get provider by type
- **GIVEN** the system is configured with multiple voice clone providers
- **WHEN** requesting a provider by type
- **THEN** the system SHALL return the corresponding provider instance
- **AND** the provider SHALL implement the `VoiceCloneProvider` interface

#### Scenario: Provider not found
- **GIVEN** the system is configured with a default provider
- **WHEN** requesting a non-existent provider type
- **THEN** the system SHALL fallback to the default provider
- **AND** log a warning message

### Requirement: Voice Cloning
The system SHALL support voice cloning through the provider interface, accepting an audio file URL and returning a unique voice ID.

#### Scenario: Successful voice cloning with CosyVoice
- **GIVEN** a valid CosyVoice provider is configured
- **WHEN** submitting a voice clone request with audio URL
- **THEN** the system SHALL return a voice ID
- **AND** the voice ID SHALL be usable for subsequent TTS synthesis

#### Scenario: Voice cloning failure
- **GIVEN** the provider API is unavailable or returns an error
- **WHEN** submitting a voice clone request
- **THEN** the system SHALL throw a `VOICE_TTS_FAILED` exception
- **AND** log the error details for debugging

### Requirement: Text-to-Speech Synthesis
The system SHALL support TTS synthesis through cloned voices or system voices, accepting text input and returning audio data.

#### Scenario: TTS with cloned voice
- **GIVEN** a valid voice ID from a previous clone operation
- **WHEN** submitting a TTS request with text and voice ID
- **THEN** the system SHALL return audio data in the specified format
- **AND** the audio SHALL match the cloned voice characteristics

#### Scenario: TTS with system voice
- **GIVEN** a system voice ID is configured
- **WHEN** submitting a TTS request with text and system voice ID
- **THEN** the system SHALL return audio data using the system voice
- **AND** the audio SHALL match the system voice characteristics

#### Scenario: TTS with reference audio (file URL)
- **GIVEN** a reference audio URL and transcription text
- **WHEN** submitting a TTS request with file URL
- **THEN** the system SHALL perform on-the-fly voice cloning
- **AND** return audio data matching the reference voice

### Requirement: Configuration Management
The system SHALL support multi-provider configuration through a unified configuration structure.

#### Scenario: Configure multiple providers
- **GIVEN** the application configuration file
- **WHEN** configuring multiple voice providers
- **THEN** each provider SHALL have independent `enabled` flag
- **AND** the system SHALL only use enabled providers

#### Scenario: Default provider selection
- **GIVEN** the configuration specifies a `default-provider`
- **WHEN** no provider is explicitly specified
- **THEN** the system SHALL use the default provider
- **AND** fallback to `cosyvoice` if default is not configured

#### Scenario: Backward compatibility
- **GIVEN** existing configuration using `yudao.cosyvoice.*`
- **WHEN** the system starts
- **THEN** the system SHALL automatically migrate to new config structure
- **AND** existing functionality SHALL remain unchanged

### Requirement: Provider Factory
The system SHALL provide a factory component for managing provider instances and resolving providers by type.

#### Scenario: Factory resolves provider
- **GIVEN** the factory is initialized with provider configurations
- **WHEN** calling `factory.getProvider("cosyvoice")`
- **THEN** the factory SHALL return the CosyVoiceProvider instance
- **AND** cache the instance for subsequent requests

#### Scenario: Factory returns default
- **GIVEN** the factory is configured with default provider
- **WHEN** calling `factory.getProvider(null)`
- **THEN** the factory SHALL return the default provider instance

## MODIFIED Requirements

### Requirement: Voice Creation Flow
The voice creation process SHALL use the provider abstraction layer instead of directly calling CosyVoice client.

#### Scenario: Create voice with CosyVoice
- **GIVEN** a user uploads a voice audio file
- **WHEN** creating a voice configuration through the API
- **THEN** the system SHALL:
  1. Validate the file exists and belongs to voice category
  2. Call `provider.cloneVoice()` with the audio URL
  3. Store the returned `voiceId` in the database
  4. Return success response with voice configuration ID

#### Scenario: Create voice with transcription
- **GIVEN** a voice configuration is created without transcription
- **WHEN** the user triggers transcription
- **THEN** the system SHALL:
  1. Fetch the audio file URL
  2. Call the transcription service
  3. Store the transcription text
  4. Update the voice configuration

### Requirement: Voice Preview
The voice preview functionality SHALL work with both cloned voices (voiceId) and reference audio (file URL).

#### Scenario: Preview cloned voice
- **GIVEN** a voice configuration with a valid `voiceId`
- **WHEN** requesting a preview with custom text
- **THEN** the system SHALL call `provider.synthesize()` with the voiceId
- **AND** return audio data in Base64 format

#### Scenario: Preview with reference audio
- **GIVEN** a voice configuration without `voiceId` but with audio file
- **WHEN** requesting a preview
- **THEN** the system SHALL call `provider.synthesize()` with the file URL
- **AND** use the stored transcription as reference text
- **AND** return audio data in Base64 format

## REMOVED Requirements

None. This change is additive and refactoring only.