# Implementation Plan

- [x] 1. Set up project structure and dependencies
  - Create backend directory with FastAPI project structure
  - Create frontend directory with React + TypeScript + Vite
  - Configure Python virtual environment and install dependencies (fastapi, uvicorn, kokoro, soundfile, python-multipart)
  - Install espeak-ng system dependency
  - Configure Node.js project with TypeScript, React, and Vite
  - Set up environment variable configuration for both projects
  - _Requirements: 9.6, 10.2, 11.1_

- [x] 2. Implement backend API foundation
  - Create FastAPI application with CORS middleware
  - Define Pydantic models for requests and responses (RoleDetectionRequest, RolesResponse, TTSRequest, ErrorResponse)
  - Implement /api/health endpoint
  - Set up error handling middleware
  - Configure logging
  - _Requirements: 9.1, 9.2, 9.4_

- [ ]* 2.1 Write unit tests for API foundation
  - Test health endpoint returns correct status
  - Test CORS headers are set correctly
  - Test error response format
  - _Requirements: 9.1_

- [x] 3. Implement role detection service
  - Create RoleDetector class with pattern matching logic
  - Implement colon pattern extraction ("RoleName:")
  - Implement bracket pattern extraction ("[RoleName]")
  - Implement role deduplication logic
  - Implement fallback to default "Narrator" role
  - Create /api/tts/roles endpoint using RoleDetector
  - _Requirements: 2.1, 2.2, 2.3, 2.4, 2.5, 2.6_

- [ ]* 3.1 Write property test for colon pattern extraction
  - **Property 2: Role extraction from colon pattern**
  - **Validates: Requirements 2.2**

- [ ]* 3.2 Write property test for bracket pattern extraction
  - **Property 3: Role extraction from bracket pattern**
  - **Validates: Requirements 2.3**

- [ ]* 3.3 Write property test for role deduplication
  - **Property 4: Role deduplication**
  - **Validates: Requirements 2.5**

- [ ]* 3.4 Write property test for role response structure
  - **Property 5: Role response structure**
  - **Validates: Requirements 2.6**

- [ ]* 3.5 Write unit tests for role detection edge cases
  - Test empty text returns default "Narrator" role
  - Test text with no role markers returns "Narrator"
  - Test mixed patterns (both colon and bracket)
  - _Requirements: 2.4_

- [x] 4. Implement TTS service with Kokoro integration
  - Create TTSService class
  - Implement KPipeline initialization and caching per language
  - Implement text segmentation logic to identify role markers and split text
  - Implement segment synthesis with voice assignment
  - Implement audio concatenation at 24 kHz
  - Handle fallback to default voice for unmapped roles
  - _Requirements: 10.1, 10.3, 10.4, 6.2, 6.3, 6.4, 6.5, 6.6_

- [ ]* 4.1 Write property test for pipeline initialization
  - **Property 26: Pipeline initialization per language**
  - **Validates: Requirements 10.3**

- [ ]* 4.2 Write property test for voice assignment per segment
  - **Property 13: Voice assignment per segment**
  - **Validates: Requirements 6.3**

- [ ]* 4.3 Write property test for text chunking
  - **Property 14: Text chunking for long content**
  - **Validates: Requirements 6.5**

- [ ]* 4.4 Write property test for audio concatenation
  - **Property 15: Audio concatenation at 24 kHz**
  - **Validates: Requirements 6.6**

- [ ]* 4.5 Write property test for audio sample rate
  - **Property 27: Audio sample rate**
  - **Validates: Requirements 10.4**

- [ ]* 4.6 Write unit tests for TTS service
  - Test default voice fallback for unmapped roles
  - Test synthesis with different language codes (a, b, f, j)
  - Test synthesis with different voice IDs
  - _Requirements: 6.4, 10.5, 10.6_

- [x] 5. Implement audio generation endpoint
  - Create /api/tts POST endpoint
  - Validate request fields (text, lang, roles, speed)
  - Integrate TTSService to generate audio
  - Convert audio to bytes (WAV or MP3 format)
  - Stream response with correct Content-Type header
  - Add Content-Disposition header with filename
  - _Requirements: 6.1, 6.7, 6.8, 9.5_

- [ ]* 5.1 Write property test for request validation
  - **Property 25: Request validation**
  - **Validates: Requirements 9.5**

- [ ]* 5.2 Write property test for audio response headers
  - **Property 16: Audio response content type**
  - **Property 17: Audio response filename**
  - **Validates: Requirements 6.7, 6.8**

- [ ]* 5.3 Write unit tests for generation endpoint
  - Test successful generation returns audio
  - Test missing required fields returns 400 error
  - Test invalid language code returns error
  - Test invalid voice ID returns error
  - _Requirements: 9.5_

- [x] 6. Create backend Dockerfile and docker-compose
  - Write Dockerfile with Python base image
  - Install system dependencies (espeak-ng)
  - Install Python dependencies
  - Copy backend code
  - Expose port 8000
  - Set CMD to start Uvicorn server
  - Create docker-compose.yml for easy orchestration
  - _Requirements: 11.1, 11.2, 11.3, 11.4, 11.5, 11.6_

- [ ]* 6.1 Test Docker container builds and runs
  - Build Docker image successfully
  - Start container and verify health endpoint responds
  - _Requirements: 11.5_

- [x] 7. Set up React frontend project structure
  - Initialize Vite project with React and TypeScript
  - Configure TypeScript with strict mode
  - Set up Tailwind CSS for styling
  - Create component directory structure
  - Configure environment variables (.env file with VITE_API_BASE_URL)
  - _Requirements: 9.6, 12.3_

- [x] 8. Implement API client module
  - Create src/api/tts.ts with TypeScript interfaces (Role, RoleWithVoice, RolesResponse, GenerateRequest)
  - Implement detectRoles() function
  - Implement generateAudiobook() function
  - Implement checkHealth() function
  - Add error handling for network failures
  - Use VITE_API_BASE_URL environment variable
  - _Requirements: 9.6, 9.7_

- [ ]* 8.1 Write unit tests for API client
  - Test API client reads VITE_API_BASE_URL
  - Test error handling for network failures
  - Mock fetch calls and verify request format
  - _Requirements: 9.6_

- [x] 9. Implement text input component
  - Create TextInputSection component
  - Add large multiline textarea
  - Add "Next: Assign voices" button
  - Implement text validation (non-empty)
  - Show validation message for empty text
  - Disable button when text is empty
  - _Requirements: 1.1, 1.2, 1.3, 1.4_

- [ ]* 9.1 Write property test for text acceptance
  - **Property 1: Text persistence invariant** (partial - input phase)
  - **Validates: Requirements 1.2**

- [ ]* 9.2 Write unit tests for text input component
  - Test textarea renders correctly
  - Test button is disabled when text is empty
  - Test button is enabled when text is present
  - Test validation message appears for empty text
  - _Requirements: 1.1, 1.3, 1.4_

- [x] 10. Implement voice assignment component
  - Create VoiceAssignmentSection component
  - Display "Assign voices to roles" title
  - Render role list with labels and dropdowns
  - Populate dropdowns with Kokoro voice options (af_bella, af_sarah, am_adam, bf_emma, etc.)
  - Implement voice selection handler
  - Add language selector with options (American English, British English, French, Japanese)
  - Add speed slider (0.5x - 1.5x range)
  - Add "Generate Audiobook" button
  - Disable generate button until all roles have voices
  - _Requirements: 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 4.1, 4.2, 4.3, 4.4, 5.1, 5.2, 5.3_

- [ ]* 10.1 Write property test for voice assignment storage
  - **Property 6: Voice assignment storage**
  - **Validates: Requirements 3.4**

- [ ]* 10.2 Write property test for generate button state
  - **Property 7: Generate button disabled when incomplete**
  - **Property 8: Generate button enabled when complete**
  - **Validates: Requirements 3.5, 3.6**

- [ ]* 10.3 Write property test for language selection
  - **Property 9: Language selection storage**
  - **Validates: Requirements 4.4**

- [ ]* 10.4 Write property test for speed range
  - **Property 10: Speed range constraints**
  - **Validates: Requirements 5.2**

- [ ]* 10.5 Write property test for speed storage
  - **Property 11: Speed value storage**
  - **Validates: Requirements 5.4**

- [ ]* 10.6 Write unit tests for voice assignment component
  - Test section title displays correctly
  - Test dropdowns contain required voices
  - Test language selector contains required options
  - Test default language is American English
  - Test default speed is 1.0x
  - Test speed slider enforces min/max bounds
  - _Requirements: 3.1, 3.3, 4.2, 4.3, 5.3_

- [x] 11. Implement audio player component
  - Create AudioPlayerSection component
  - Display HTML5 audio element with controls
  - Add "Download audiobook" button
  - Implement download functionality using blob URL
  - _Requirements: 7.2, 7.3, 7.4, 7.5_

- [ ]* 11.1 Write property test for blob URL creation
  - **Property 18: Blob URL creation**
  - **Validates: Requirements 7.1**

- [ ]* 11.2 Write property test for download functionality
  - **Property 19: Download functionality**
  - **Validates: Requirements 7.5**

- [ ]* 11.3 Write unit tests for audio player component
  - Test audio element renders with controls
  - Test download button appears
  - Test download button triggers file save
  - _Requirements: 7.2, 7.3, 7.4_

- [x] 12. Implement main App component with workflow orchestration
  - Create App component with state management
  - Implement phase transitions (input → assignment → generated)
  - Wire up text input to role detection
  - Wire up voice assignment to audio generation
  - Implement loading states for async operations
  - Implement error handling and display
  - Add warning message for long text
  - Ensure text persists across phases
  - _Requirements: 1.5, 6.1, 8.1, 8.2, 8.3, 8.4_

- [ ]* 12.1 Write property test for text persistence
  - **Property 1: Text persistence invariant** (complete workflow)
  - **Validates: Requirements 1.5**

- [ ]* 12.2 Write property test for generation request completeness
  - **Property 12: Generation request completeness**
  - **Validates: Requirements 6.1**

- [ ]* 12.3 Write property test for loading states
  - **Property 20: Loading state during role detection**
  - **Property 21: Loading state during generation**
  - **Validates: Requirements 8.1, 8.2**

- [ ]* 12.4 Write property test for long text warning
  - **Property 22: Long text warning**
  - **Validates: Requirements 8.3**

- [ ]* 12.5 Write property test for error display
  - **Property 23: Error message display**
  - **Validates: Requirements 8.4**

- [ ]* 12.6 Write unit tests for App component
  - Test phase transitions work correctly
  - Test error states display messages
  - Test loading states appear during API calls
  - _Requirements: 8.1, 8.2, 8.4_

- [x] 13. Add responsive styling and mobile support
  - Apply Tailwind CSS classes for responsive layout
  - Ensure text areas and controls are mobile-friendly
  - Test on different screen sizes
  - Ensure touch targets are appropriately sized
  - _Requirements: 12.1, 12.2, 12.3, 12.4_

- [x] 14. Create comprehensive README documentation
  - Document Kokoro model setup and configuration
  - Provide backend setup instructions (local and Docker)
  - Provide frontend setup instructions
  - Include example commands for running both services
  - Add workflow testing steps
  - Include troubleshooting section
  - _Requirements: 13.1, 13.2, 13.3, 13.4, 13.5_

- [x] 15. Implement Ollama integration service
  - Create OllamaService class in services/ollama_service.py
  - Implement connection to Ollama API using httpx
  - Configure OLLAMA_BASE_URL environment variable (default: http://localhost:11434)
  - Implement detect_speakers() method with structured prompt
  - Implement prompt builder for speaker detection
  - Implement JSON response parser
  - Implement is_available() health check method
  - Add timeout handling (30 seconds)
  - _Requirements: 14.1, 14.2, 14.3, 14.6_

- [ ]* 15.1 Write property test for Ollama speaker detection
  - **Property 28: Ollama speaker detection**
  - **Validates: Requirements 14.1**

- [ ]* 15.2 Write property test for JSON response parsing
  - **Property 29: Ollama JSON response parsing**
  - **Validates: Requirements 14.3**

- [ ]* 15.3 Write unit tests for Ollama service
  - Test connection to Ollama
  - Test prompt construction
  - Test JSON parsing with various formats
  - Test timeout handling
  - Test error handling for unavailable service
  - _Requirements: 14.1, 14.2, 14.3_

- [x] 16. Integrate Ollama into role detection
  - Update RoleDetector to use OllamaService
  - Implement _detect_with_ollama() method
  - Add fallback logic: try Ollama first, then pattern matching
  - Implement role merging and deduplication across both methods
  - Handle Ollama unavailable gracefully
  - Log detection method used (AI vs pattern)
  - _Requirements: 14.1, 14.4, 14.5_

- [ ]* 16.1 Write property test for Ollama fallback
  - **Property 30: Ollama fallback behavior**
  - **Validates: Requirements 14.4**

- [ ]* 16.2 Write property test for role deduplication
  - **Property 31: Role deduplication across detection methods**
  - **Validates: Requirements 14.5**

- [ ]* 16.3 Write unit tests for integrated role detection
  - Test with Ollama available
  - Test with Ollama unavailable
  - Test role merging from both sources
  - Test deduplication logic
  - _Requirements: 14.4, 14.5_

- [ ] 17. Update documentation for Ollama integration
  - Document Ollama setup in README
  - Add instructions for installing and running Ollama
  - Document llama3:8B model requirement
  - Add OLLAMA_BASE_URL environment variable to .env.example
  - Update backend README with Ollama configuration
  - Add troubleshooting section for Ollama issues
  - _Requirements: 14.6_

- [ ] 18. Final integration testing and polish
  - Test complete end-to-end workflow
  - Test with various text samples (short, long, multiple roles, no roles)
  - Test with unmarked dialogue text (relying on AI detection)
  - Test with marked text (pattern detection)
  - Test with Ollama available and unavailable
  - Test all language options (a, b, f, j)
  - Test error scenarios (network failures, invalid inputs)
  - Verify audio quality and playback
  - Test Docker deployment
  - Fix any bugs discovered during testing
  - _Requirements: All_