Add API reference

- Implement save/load buttons in dialog editor interface
- Add JSONL export/import for dialog scripts with validation
- Include timestamp-based filenames for saved scripts
- Add comprehensive error handling and user confirmations
- Create CLAUDE.md with development guidance and architecture overview

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

API_REFERENCE.md

@@ -0,0 +1,518 @@
+# Chatterbox TTS API Reference
+
+## Overview
+
+The Chatterbox TTS API is a FastAPI-based backend service that provides text-to-speech capabilities with speaker management and dialog generation features. The API supports creating custom speakers from audio samples and generating complex dialogs with multiple speakers, silences, and fine-tuned TTS parameters.
+
+**Base URL**: `http://127.0.0.1:8000`  
+**API Version**: 0.1.0  
+**Framework**: FastAPI with automatic OpenAPI documentation
+
+## Quick Start
+
+- **Interactive API Documentation**: `http://127.0.0.1:8000/docs` (Swagger UI)
+- **Alternative Documentation**: `http://127.0.0.1:8000/redoc` (ReDoc)
+- **OpenAPI Schema**: `http://127.0.0.1:8000/openapi.json`
+
+## Authentication
+
+Currently, the API does not require authentication. CORS is configured to allow requests from `localhost:8001` and `127.0.0.1:8001`.
+
+---
+
+## Endpoints
+
+### 🏠 Root Endpoint
+
+#### `GET /`
+Welcome message and API status check.
+
+**Response:**
+```json
+{
+  "message": "Welcome to the Chatterbox TTS API!"
+}
+```
+
+---
+
+## 👥 Speaker Management
+
+### `GET /api/speakers/`
+Retrieve all available speakers.
+
+**Response Model:** `List[Speaker]`
+
+**Example Response:**
+```json
+[
+  {
+    "id": "speaker_001",
+    "name": "John Doe",
+    "sample_path": "/path/to/speaker_samples/john_doe.wav"
+  },
+  {
+    "id": "speaker_002", 
+    "name": "Jane Smith",
+    "sample_path": "/path/to/speaker_samples/jane_smith.wav"
+  }
+]
+```
+
+**Status Codes:**
+- `200`: Success
+
+---
+
+### `POST /api/speakers/`
+Create a new speaker from an audio sample.
+
+**Request Type:** `multipart/form-data`
+
+**Parameters:**
+- `name` (form field, required): Speaker name
+- `audio_file` (file upload, required): Audio sample file (WAV, MP3, etc.)
+
+**Response Model:** `SpeakerResponse`
+
+**Example Response:**
+```json
+{
+  "id": "speaker_003",
+  "name": "Alex Johnson",
+  "message": "Speaker added successfully."
+}
+```
+
+**Status Codes:**
+- `201`: Speaker created successfully
+- `400`: Invalid file type or missing file
+- `500`: Server error during speaker creation
+
+**Example cURL:**
+```bash
+curl -X POST "http://127.0.0.1:8000/api/speakers/" \
+  -F "name=Alex Johnson" \
+  -F "audio_file=@/path/to/sample.wav"
+```
+
+---
+
+### `GET /api/speakers/{speaker_id}`
+Get details for a specific speaker.
+
+**Path Parameters:**
+- `speaker_id` (string, required): Unique speaker identifier
+
+**Response Model:** `Speaker`
+
+**Example Response:**
+```json
+{
+  "id": "speaker_001",
+  "name": "John Doe", 
+  "sample_path": "/path/to/speaker_samples/john_doe.wav"
+}
+```
+
+**Status Codes:**
+- `200`: Success
+- `404`: Speaker not found
+
+---
+
+### `DELETE /api/speakers/{speaker_id}`
+Delete a speaker by ID.
+
+**Path Parameters:**
+- `speaker_id` (string, required): Unique speaker identifier
+
+**Example Response:**
+```json
+{
+  "message": "Speaker deleted successfully"
+}
+```
+
+**Status Codes:**
+- `200`: Speaker deleted successfully
+- `404`: Speaker not found
+
+---
+
+## 🎭 Dialog Generation
+
+### `POST /api/dialog/generate_line`
+Generate audio for a single dialog line (speech or silence).
+
+**Request Body:** Raw JSON object representing either a `SpeechItem` or `SilenceItem`
+
+#### Speech Item Example:
+```json
+{
+  "type": "speech",
+  "speaker_id": "speaker_001",
+  "text": "Hello, this is a test message.",
+  "exaggeration": 0.7,
+  "cfg_weight": 0.6,
+  "temperature": 0.8,
+  "use_existing_audio": false,
+  "audio_url": null
+}
+```
+
+#### Silence Item Example:
+```json
+{
+  "type": "silence",
+  "duration": 2.0,
+  "use_existing_audio": false,
+  "audio_url": null
+}
+```
+
+**Response:**
+```json
+{
+  "audio_url": "/generated_audio/line_abc123def456.wav",
+  "type": "speech",
+  "text": "Hello, this is a test message."
+}
+```
+
+**Status Codes:**
+- `200`: Audio generated successfully
+- `400`: Invalid request format or unknown dialog item type
+- `404`: Speaker not found
+- `500`: Server error during generation
+
+---
+
+### `POST /api/dialog/generate`
+Generate a complete dialog from multiple speech and silence items.
+
+**Request Model:** `DialogRequest`
+
+**Request Body:**
+```json
+{
+  "dialog_items": [
+    {
+      "type": "speech",
+      "speaker_id": "speaker_001", 
+      "text": "Welcome to our podcast!",
+      "exaggeration": 0.5,
+      "cfg_weight": 0.5,
+      "temperature": 0.8
+    },
+    {
+      "type": "silence",
+      "duration": 1.0
+    },
+    {
+      "type": "speech",
+      "speaker_id": "speaker_002",
+      "text": "Thank you for having me!",
+      "exaggeration": 0.6,
+      "cfg_weight": 0.7,
+      "temperature": 0.9
+    }
+  ],
+  "output_base_name": "podcast_episode_01"
+}
+```
+
+**Response Model:** `DialogResponse`
+
+**Example Response:**
+```json
+{
+  "log": "Processing dialog with 3 items...\nGenerating speech for item 1...\nGenerating silence for item 2...\nGenerating speech for item 3...\nConcatenating audio segments...\nZIP archive created at: /path/to/output.zip",
+  "concatenated_audio_url": "/generated_audio/podcast_episode_01_concatenated.wav",
+  "zip_archive_url": "/generated_audio/podcast_episode_01_archive.zip", 
+  "temp_dir_path": "/path/to/temp/directory",
+  "error_message": null
+}
+```
+
+**Status Codes:**
+- `200`: Dialog generated successfully
+- `400`: Invalid request format or validation errors
+- `404`: Speaker or file not found
+- `500`: Server error during generation
+
+---
+
+## 📁 Static File Serving
+
+### `GET /generated_audio/{filename}`
+Serve generated audio files and ZIP archives.
+
+**Path Parameters:**
+- `filename` (string, required): Name of the generated file
+
+**Response:** Binary audio file or ZIP archive
+
+**Example URLs:**
+- `http://127.0.0.1:8000/generated_audio/dialog_concatenated.wav`
+- `http://127.0.0.1:8000/generated_audio/dialog_archive.zip`
+
+---
+
+## 📋 Data Models
+
+### Speaker Models
+
+#### `Speaker`
+```json
+{
+  "id": "string",
+  "name": "string", 
+  "sample_path": "string|null"
+}
+```
+
+#### `SpeakerResponse`
+```json
+{
+  "id": "string",
+  "name": "string",
+  "message": "string|null"
+}
+```
+
+### Dialog Models
+
+#### `SpeechItem`
+```json
+{
+  "type": "speech",
+  "speaker_id": "string",
+  "text": "string",
+  "exaggeration": 0.5,        // 0.0-2.0, controls expressiveness
+  "cfg_weight": 0.5,          // 0.0-2.0, alignment with speaker characteristics  
+  "temperature": 0.8,         // 0.0-2.0, randomness in generation
+  "use_existing_audio": false,
+  "audio_url": "string|null"
+}
+```
+
+#### `SilenceItem`
+```json
+{
+  "type": "silence",
+  "duration": 1.0,            // seconds, must be > 0
+  "use_existing_audio": false,
+  "audio_url": "string|null"
+}
+```
+
+#### `DialogRequest`
+```json
+{
+  "dialog_items": [
+    // Array of SpeechItem and/or SilenceItem objects
+  ],
+  "output_base_name": "string"  // Base name for output files
+}
+```
+
+#### `DialogResponse`
+```json
+{
+  "log": "string",                        // Processing log
+  "concatenated_audio_url": "string|null", // URL to final audio
+  "zip_archive_url": "string|null",       // URL to ZIP archive
+  "temp_dir_path": "string|null",         // Server temp directory
+  "error_message": "string|null"          // Error details if failed
+}
+```
+
+---
+
+## 🎛️ TTS Parameters
+
+### Exaggeration (`exaggeration`)
+- **Range**: 0.0 - 2.0
+- **Default**: 0.5
+- **Description**: Controls the expressiveness of speech. Higher values produce more exaggerated, emotional speech.
+
+### CFG Weight (`cfg_weight`)
+- **Range**: 0.0 - 2.0  
+- **Default**: 0.5
+- **Description**: Classifier-Free Guidance weight. Higher values make speech more aligned with the prompt text and speaker characteristics.
+
+### Temperature (`temperature`)
+- **Range**: 0.0 - 2.0
+- **Default**: 0.8
+- **Description**: Controls randomness in generation. Lower values produce more deterministic speech, higher values add more variation.
+
+---
+
+## 🔧 Configuration
+
+### Environment Variables
+The API uses the following directory structure (configurable in `app/config.py`):
+
+- **Speaker Samples**: `{PROJECT_ROOT}/speaker_data/speaker_samples/`
+- **Generated Audio**: `{PROJECT_ROOT}/backend/tts_generated_dialogs/`
+- **Temporary Files**: `{PROJECT_ROOT}/tts_temp_outputs/`
+
+### CORS Settings
+- Allowed Origins: `http://localhost:8001`, `http://127.0.0.1:8001`
+- Allowed Methods: All
+- Allowed Headers: All
+- Credentials: Enabled
+
+---
+
+## 🚀 Usage Examples
+
+### Python Client Example
+
+```python
+import requests
+import json
+
+# Base URL
+BASE_URL = "http://127.0.0.1:8000"
+
+# Get all speakers
+speakers = requests.get(f"{BASE_URL}/api/speakers/").json()
+print("Available speakers:", speakers)
+
+# Generate a simple dialog
+dialog_request = {
+    "dialog_items": [
+        {
+            "type": "speech",
+            "speaker_id": speakers[0]["id"],
+            "text": "Hello world!",
+            "exaggeration": 0.7,
+            "cfg_weight": 0.6,
+            "temperature": 0.9
+        },
+        {
+            "type": "silence", 
+            "duration": 1.0
+        }
+    ],
+    "output_base_name": "test_dialog"
+}
+
+response = requests.post(
+    f"{BASE_URL}/api/dialog/generate",
+    json=dialog_request
+)
+
+if response.status_code == 200:
+    result = response.json()
+    print("Dialog generated!")
+    print("Audio URL:", result["concatenated_audio_url"])
+    print("ZIP URL:", result["zip_archive_url"])
+else:
+    print("Error:", response.text)
+```
+
+### JavaScript/Frontend Example
+
+```javascript
+// Generate dialog
+const dialogRequest = {
+  dialog_items: [
+    {
+      type: "speech",
+      speaker_id: "speaker_001",
+      text: "Welcome to our show!",
+      exaggeration: 0.6,
+      cfg_weight: 0.5,
+      temperature: 0.8
+    }
+  ],
+  output_base_name: "intro"
+};
+
+fetch('http://127.0.0.1:8000/api/dialog/generate', {
+  method: 'POST',
+  headers: {
+    'Content-Type': 'application/json',
+  },
+  body: JSON.stringify(dialogRequest)
+})
+.then(response => response.json())
+.then(data => {
+  console.log('Dialog generated:', data);
+  // Play the audio
+  const audio = new Audio(data.concatenated_audio_url);
+  audio.play();
+});
+```
+
+---
+
+## ⚠️ Error Handling
+
+### Common Error Responses
+
+#### 400 Bad Request
+```json
+{
+  "detail": "Invalid value or configuration: Text cannot be empty"
+}
+```
+
+#### 404 Not Found
+```json
+{
+  "detail": "Speaker sample for ID 'invalid_speaker' not found."
+}
+```
+
+#### 500 Internal Server Error
+```json
+{
+  "detail": "Runtime error during dialog generation: CUDA out of memory"
+}
+```
+
+### Error Categories
+- **Validation Errors**: Invalid input format, missing required fields
+- **Resource Errors**: Speaker not found, file not accessible
+- **Processing Errors**: TTS model failures, audio processing issues
+- **System Errors**: Memory issues, disk space, model loading failures
+
+---
+
+## 🔍 Development & Debugging
+
+### Running the Server
+```bash
+# From project root
+uvicorn backend.app.main:app --reload --host 0.0.0.0 --port 8000
+```
+
+### API Documentation
+- **Swagger UI**: `http://127.0.0.1:8000/docs`
+- **ReDoc**: `http://127.0.0.1:8000/redoc`
+
+### Logging
+The API provides detailed logging in the `DialogResponse.log` field for dialog generation operations.
+
+### File Management
+- Generated files are stored in `backend/tts_generated_dialogs/`
+- Temporary processing files are kept for inspection (not auto-deleted)
+- ZIP archives contain individual audio segments plus concatenated result
+
+---
+
+## 📝 Notes
+
+- The API automatically loads and unloads TTS models to manage memory usage
+- Speaker audio samples should be clear, single-speaker recordings for best results
+- Large dialogs may take significant time to process depending on hardware
+- Generated files are served statically and persist until manually cleaned up
+
+---
+
+*Generated on: 2025-06-06*  
+*API Version: 0.1.0*

CLAUDE.md

@@ -0,0 +1,102 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Common Development Commands
+
+### Backend (FastAPI)
+
+```bash
+# Install backend dependencies (run from project root)
+pip install -r backend/requirements.txt
+
+# Run backend development server (run from project root)
+uvicorn backend.app.main:app --reload --host 0.0.0.0 --port 8000
+
+# Run backend tests
+python backend/run_api_test.py
+
+# Backend API accessible at http://127.0.0.1:8000
+# API docs at http://127.0.0.1:8000/docs
+```
+
+### Frontend Testing
+
+```bash
+# Run frontend tests
+npm test
+```
+
+### Alternative Interfaces
+
+```bash
+# Run Gradio interface (standalone TTS app)
+python gradio_app.py
+```
+
+## Architecture Overview
+
+This is a full-stack TTS (Text-to-Speech) application with three interfaces:
+
+1. **Modern web frontend** (vanilla JS) - Interactive dialog editor at `frontend/`
+2. **FastAPI backend** - REST API at `backend/`  
+3. **Gradio interface** - Alternative UI in `gradio_app.py`
+
+### Frontend-Backend Communication
+
+- **Frontend**: Vanilla JS (ES6 modules) serving on port 8001
+- **Backend**: FastAPI serving on port 8000
+- **API Base**: `http://localhost:8000/api`
+- **CORS**: Configured for frontend communication
+- **File Serving**: Generated audio served via `/generated_audio/` endpoint
+
+### Key API Endpoints
+
+- `/api/speakers/` - Speaker CRUD operations
+- `/api/dialog/generate/` - Full dialog generation  
+- `/api/dialog/generate_line/` - Single line generation
+- `/generated_audio/` - Static audio file serving
+
+### Backend Service Architecture
+
+Located in `backend/app/services/`:
+
+- **TTSService**: Chatterbox TTS model lifecycle management
+- **SpeakerManagementService**: Speaker data and sample management
+- **DialogProcessorService**: Dialog script to audio processing
+- **AudioManipulationService**: Audio concatenation and ZIP creation
+
+### Frontend Architecture
+
+- **Modular design**: `api.js` (API layer) + `app.js` (app logic)
+- **No framework**: Modern vanilla JavaScript with ES6+ features
+- **Interactive editor**: Table-based dialog creation with drag-drop reordering
+
+### Data Flow
+
+1. User creates dialog in frontend table editor
+2. Frontend sends dialog items to `/api/dialog/generate/`
+3. Backend processes speech/silence items via services
+4. TTS generates audio, segments concatenated
+5. ZIP archive created with all outputs
+6. Frontend receives URLs for playback/download
+
+### Speaker Configuration
+
+- **Location**: `speaker_data/speakers.yaml` and `speaker_data/speaker_samples/`
+- **Format**: YAML config referencing WAV audio samples
+- **Management**: Both API endpoints and file-based configuration
+
+### Output Organization
+
+- `dialog_output/` - Generated dialog files
+- `single_output/` - Single utterance outputs  
+- `tts_outputs/` - Raw TTS generation files
+- Generated ZIPs contain organized file structure
+
+## Development Setup Notes
+
+- Python virtual environment expected at project root (`.venv`)
+- Backend commands run from project root, not `backend/` directory
+- Frontend served separately (typically port 8001)
+- Speaker samples must be WAV format in `speaker_data/speaker_samples/`

backend/app/config.py

@@ -17,3 +17,5 @@ TTS_TEMP_OUTPUT_DIR = PROJECT_ROOT / "tts_temp_outputs"
 # These are stored within the 'backend' directory to be easily servable.
 DIALOG_OUTPUT_PARENT_DIR = PROJECT_ROOT / "backend"
 DIALOG_GENERATED_DIR = DIALOG_OUTPUT_PARENT_DIR / "tts_generated_dialogs"
+# Alias for clarity and backward compatibility
+DIALOG_OUTPUT_DIR = DIALOG_GENERATED_DIR

backend/app/models/dialog_models.py

@@ -11,10 +11,14 @@ class SpeechItem(DialogItemBase):
     exaggeration: Optional[float] = Field(0.5, description="Controls the expressiveness of the speech. Higher values lead to more exaggerated speech. Default from Gradio.")
     cfg_weight: Optional[float] = Field(0.5, description="Classifier-Free Guidance weight. Higher values make the speech more aligned with the prompt text and speaker characteristics. Default from Gradio.")
     temperature: Optional[float] = Field(0.8, description="Controls randomness in generation. Lower values make speech more deterministic, higher values more varied. Default from Gradio.")
+    use_existing_audio: Optional[bool] = Field(False, description="If true and audio_url is provided, use the existing audio file instead of generating new audio for this line.")
+    audio_url: Optional[str] = Field(None, description="Path or URL to pre-generated audio for this line (used if use_existing_audio is true).")
 
 class SilenceItem(DialogItemBase):
     type: Literal['silence'] = 'silence'
     duration: float = Field(..., gt=0, description="Duration of the silence in seconds.")
+    use_existing_audio: Optional[bool] = Field(False, description="If true and audio_url is provided, use the existing audio file for silence instead of generating a new silent segment.")
+    audio_url: Optional[str] = Field(None, description="Path or URL to pre-generated audio for this silence (used if use_existing_audio is true).")
 
 class DialogRequest(BaseModel):
     dialog_items: List[Union[SpeechItem, SilenceItem]] = Field(..., description="A list of speech and silence items.")

backend/app/routers/dialog.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
 from pathlib import Path
 import shutil
+import os
 
 from app.models.dialog_models import DialogRequest, DialogResponse
 from app.services.tts_service import TTSService
@@ -32,6 +33,68 @@ def get_audio_manipulation_service():
     return AudioManipulationService()
 
 # --- Helper function to manage TTS model loading/unloading --- 
+
+from app.models.dialog_models import SpeechItem, SilenceItem
+from app.services.tts_service import TTSService
+from app.services.audio_manipulation_service import AudioManipulationService
+from app.services.speaker_service import SpeakerManagementService
+from fastapi import Body
+import uuid
+from pathlib import Path
+
+@router.post("/generate_line")
+async def generate_line(
+    item: dict = Body(...),
+    tts_service: TTSService = Depends(get_tts_service),
+    audio_manipulator: AudioManipulationService = Depends(get_audio_manipulation_service),
+    speaker_service: SpeakerManagementService = Depends(get_speaker_management_service)
+):
+    """
+    Generate audio for a single dialog line (speech or silence).
+    Returns the URL of the generated audio file, or error details on failure.
+    """
+    try:
+        if item.get("type") == "speech":
+            speech = SpeechItem(**item)
+            filename_base = f"line_{uuid.uuid4().hex}"
+            out_dir = Path(config.DIALOG_GENERATED_DIR)
+            # Get speaker sample path
+            speaker_info = speaker_service.get_speaker_by_id(speech.speaker_id)
+            if not speaker_info or not getattr(speaker_info, 'sample_path', None):
+                raise HTTPException(status_code=404, detail=f"Speaker sample for ID '{speech.speaker_id}' not found.")
+            speaker_sample_path = speaker_info.sample_path
+            # Ensure absolute path
+            if not os.path.isabs(speaker_sample_path):
+                speaker_sample_path = str((Path(config.SPEAKER_SAMPLES_DIR) / Path(speaker_sample_path).name).resolve())
+            # Generate speech (async)
+            out_path = await tts_service.generate_speech(
+                text=speech.text,
+                speaker_sample_path=speaker_sample_path,
+                output_filename_base=filename_base,
+                speaker_id=speech.speaker_id,
+                output_dir=out_dir,
+                exaggeration=speech.exaggeration,
+                cfg_weight=speech.cfg_weight,
+                temperature=speech.temperature
+            )
+            audio_url = f"/generated_audio/{out_path.name}"
+        elif item.get("type") == "silence":
+            silence = SilenceItem(**item)
+            filename = f"silence_{uuid.uuid4().hex}.wav"
+            out_path = Path(config.DIALOG_GENERATED_DIR) / filename
+            # Generate silence tensor and save as WAV
+            silence_tensor = audio_manipulator._create_silence(silence.duration)
+            import torchaudio
+            torchaudio.save(str(out_path), silence_tensor, audio_manipulator.sample_rate)
+            audio_url = f"/generated_audio/{filename}"
+        else:
+            raise HTTPException(status_code=400, detail="Unknown dialog item type.")
+        return {"audio_url": audio_url}
+    except Exception as e:
+        import traceback
+        tb = traceback.format_exc()
+        raise HTTPException(status_code=500, detail=f"Exception: {str(e)}\nTraceback:\n{tb}")
+
 async def manage_tts_model_lifecycle(tts_service: TTSService, task_function, *args, **kwargs):
     """Loads TTS model, executes task, then unloads model."""
     try:

backend/app/services/dialog_processor_service.py

@@ -86,11 +86,58 @@ class DialogProcessorService:
         dialog_temp_dir.mkdir(parents=True, exist_ok=True)
         processing_log.append(f"Created temporary directory for segments: {dialog_temp_dir}")
 
+        import shutil
         segment_idx = 0
         for i, item in enumerate(dialog_items):
             item_type = item.get("type")
             processing_log.append(f"Processing item {i+1}: type='{item_type}'")
 
+            # --- Universal: Handle reuse of existing audio for both speech and silence ---
+            use_existing_audio = item.get("use_existing_audio", False)
+            audio_url = item.get("audio_url")
+            if use_existing_audio and audio_url:
+                # Determine source path (handle both absolute and relative)
+                # Map web URL to actual file location in tts_generated_dialogs
+                if audio_url.startswith("/generated_audio/"):
+                    src_audio_path = config.DIALOG_OUTPUT_DIR / audio_url[len("/generated_audio/"):]
+                else:
+                    src_audio_path = Path(audio_url)
+                    if not src_audio_path.is_absolute():
+                        # Assume relative to the generated audio root dir
+                        src_audio_path = config.DIALOG_OUTPUT_DIR / audio_url.lstrip("/\\")
+                # Now src_audio_path should point to the real file in tts_generated_dialogs
+                if src_audio_path.is_file():
+                    segment_filename = f"{output_base_name}_seg{segment_idx}_reused.wav"
+                    dest_path = (self.temp_audio_dir / output_base_name / segment_filename)
+                    try:
+                        if not src_audio_path.exists():
+                            processing_log.append(f"[REUSE] Source audio file does not exist: {src_audio_path}")
+                        else:
+                            processing_log.append(f"[REUSE] Source audio file exists: {src_audio_path}, size={src_audio_path.stat().st_size} bytes")
+                        shutil.copyfile(src_audio_path, dest_path)
+                        if not dest_path.exists():
+                            processing_log.append(f"[REUSE] Destination audio file was not created: {dest_path}")
+                        else:
+                            processing_log.append(f"[REUSE] Destination audio file created: {dest_path}, size={dest_path.stat().st_size} bytes")
+                        # Only include 'type' and 'path' so the concatenator always includes this segment
+                        segment_results.append({
+                            "type": item_type,
+                            "path": str(dest_path)
+                        })
+                        processing_log.append(f"Reused existing audio for item {i+1}: copied from {src_audio_path} to {dest_path}")
+                    except Exception as e:
+                        error_message = f"Failed to copy reused audio for item {i+1}: {e}"
+                        processing_log.append(error_message)
+                        segment_results.append({"type": "error", "message": error_message})
+                    segment_idx += 1
+                    continue
+                else:
+                    error_message = f"Audio file for reuse not found at {src_audio_path} for item {i+1}."
+                    processing_log.append(error_message)
+                    segment_results.append({"type": "error", "message": error_message})
+                    segment_idx += 1
+                    continue
+
             if item_type == "speech":
                 speaker_id = item.get("speaker_id")
                 text = item.get("text")
@@ -161,6 +208,11 @@ class DialogProcessorService:
                 processing_log.append(f"Unknown item type '{item_type}' at item {i+1}. Skipping.")
                 segment_results.append({"type": "error", "message": f"Unknown item type: {item_type}"})
 
+        # Log the full segment_results list for debugging
+        processing_log.append("[DEBUG] Final segment_results list:")
+        for idx, seg in enumerate(segment_results):
+            processing_log.append(f"  [{idx}] {seg}")
+
         return {
             "log": "\n".join(processing_log),
             "segment_files": segment_results,

backend/run_api_test.py

@@ -16,7 +16,7 @@ DIALOG_PAYLOAD = {
     "dialog_items": [
         {
             "type": "speech",
-            "speaker_id": "dummy_speaker", # Ensure this speaker exists in your speakers.yaml and has a sample .wav
+            "speaker_id": "90fcd672-ba84-441a-ac6c-0449a59653bd", # Correct UUID for dummy_speaker
             "text": "This is a test from the Python script. One, two, three.",
             "exaggeration": 1.5,
             "cfg_weight": 4.0,
@@ -28,7 +28,7 @@ DIALOG_PAYLOAD = {
         },
         {
             "type": "speech",
-            "speaker_id": "dummy_speaker",
+            "speaker_id": "90fcd672-ba84-441a-ac6c-0449a59653bd",
             "text": "Testing complete. All systems nominal."
         },
         {
@@ -104,5 +104,49 @@ def run_test():
         print(f"An unexpected error occurred: {e}")
         print("Test FAILED (Unexpected error)")
 
+def test_generate_line_speech():
+    url = f"{API_BASE_URL}/generate_line"
+    payload = {
+        "type": "speech",
+        "speaker_id": "90fcd672-ba84-441a-ac6c-0449a59653bd",  # Correct UUID for dummy_speaker
+        "text": "This is a per-line TTS test.",
+        "exaggeration": 1.0,
+        "cfg_weight": 2.0,
+        "temperature": 0.8
+    }
+    print(f"\nTesting /generate_line with speech item: {payload}")
+    response = requests.post(url, json=payload)
+    print(f"Status: {response.status_code}")
+    try:
+        data = response.json()
+        print(f"Response: {json.dumps(data, indent=2)}")
+        if response.status_code == 200 and "audio_url" in data:
+            print("Speech line test PASSED.")
+        else:
+            print("Speech line test FAILED.")
+    except Exception as e:
+        print(f"Speech line test FAILED: {e}")
+
+def test_generate_line_silence():
+    url = f"{API_BASE_URL}/generate_line"
+    payload = {
+        "type": "silence",
+        "duration": 1.25
+    }
+    print(f"\nTesting /generate_line with silence item: {payload}")
+    response = requests.post(url, json=payload)
+    print(f"Status: {response.status_code}")
+    try:
+        data = response.json()
+        print(f"Response: {json.dumps(data, indent=2)}")
+        if response.status_code == 200 and "audio_url" in data:
+            print("Silence line test PASSED.")
+        else:
+            print("Silence line test FAILED.")
+    except Exception as e:
+        print(f"Silence line test FAILED: {e}")
+
 if __name__ == "__main__":
     run_test()
+    test_generate_line_speech()
+    test_generate_line_silence()

frontend/css/style.css

@@ -1,11 +1,57 @@
-/* Modern, clean, and accessible UI styles for Chatterbox TTS */
+/* CSS Custom Properties - Color Palette */
+:root {
+    /* Primary Colors */
+    --primary-blue: #163b65;
+    --primary-blue-dark: #357ab8;
+    --primary-blue-darker: #205081;
+    
+    /* Background Colors */
+    --bg-body: #f7f9fa;
+    --bg-white: #fff;
+    --bg-light: #f3f5f7;
+    --bg-lighter: #f9fafb;
+    --bg-blue-light: #f3f7fa;
+    --bg-blue-lighter: #eaf1fa;
+    --bg-gray-light: #f7f7f7;
+    
+    /* Text Colors */
+    --text-primary: #222;
+    --text-secondary: #2b2b2b;
+    --text-tertiary: #333;
+    --text-white: #fff;
+    --text-blue: #153f6f;
+    --text-blue-dark: #357ab8;
+    --text-blue-darker: #205081;
+    
+    /* Border Colors */
+    --border-light: #1b0404;
+    --border-medium: #cfd8dc;
+    --border-blue: #b5c6df;
+    --border-gray: #e3e3e3;
+    
+    /* Status Colors */
+    --error-bg: #e74c3c;
+    --error-bg-dark: #c0392b;
+    --warning-bg: #f9e79f;
+    --warning-text: #b7950b;
+    --warning-border: #f7ca18;
+    
+    /* Header/Footer */
+    --header-bg: #222e3a;
+    
+    /* Shadows */
+    --shadow-light: rgba(44,62,80,0.04);
+    --shadow-medium: rgba(44,62,80,0.06);
+    --shadow-strong: rgba(44,62,80,0.07);
+}
+
 body {
     font-family: 'Segoe UI', 'Roboto', 'Arial', sans-serif;
     line-height: 1.7;
     margin: 0;
     padding: 0;
-    background-color: #f7f9fa;
-    color: #222;
+    background-color: var(--bg-body);
+    color: var(--text-primary);
 }
 
 .container {
@@ -15,11 +61,11 @@ body {
 }
 
 header {
-    background: #222e3a;
-    color: #fff;
+    background: var(--header-bg);
+    color: var(--text-white);
     padding: 1.5rem 0 1rem 0;
     text-align: center;
-    border-bottom: 3px solid #4a90e2;
+    border-bottom: 3px solid var(--primary-blue);
 }
 
 h1 {
@@ -49,7 +95,6 @@ main {
     padding: 0;
 }
 
-
 #results-display.panel {
     flex: 1 1 100%;
     min-width: 0;
@@ -60,52 +105,115 @@ main {
 #dialog-items-table {
     width: 100%;
     border-collapse: collapse;
-    background: #fff;
+    background: var(--bg-white);
     border-radius: 8px;
     overflow: hidden;
     font-size: 1rem;
     margin-bottom: 0;
+    table-layout: fixed;
 }
+
 #dialog-items-table th, #dialog-items-table td {
-    padding: 10px 12px;
-    border-bottom: 1px solid #e3e3e3;
+    padding: 7px 10px;
+    border: 1px solid var(--border-light);
     text-align: left;
+    vertical-align: middle;
+    font-weight: 300;
+    font-size: 0.97rem;
+    color: var(--text-secondary);
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
 }
+
+/* Widen the Text/Duration column */
+#dialog-items-table th:nth-child(3), #dialog-items-table td:nth-child(3) {
+    min-width: 320px;
+    width: 50%;
+    font-weight: 300;
+    font-size: 1rem;
+}
+
+/* Make the Speaker (2nd) column narrower */
+#dialog-items-table th:nth-child(2), #dialog-items-table td:nth-child(2) {
+    width: 60px;
+    min-width: 60px;
+    max-width: 60px;
+    text-align: center;
+}
+
+/* Make the Actions (4th) column narrower */
+#dialog-items-table th:nth-child(4), #dialog-items-table td:nth-child(4) {
+    width: 110px;
+    min-width: 90px;
+    max-width: 130px;
+    text-align: left;
+    padding-left: 0;
+    padding-right: 0;
+}
+
+#dialog-items-table th:first-child, #dialog-items-table td.type-icon-cell {
+    width: 44px;
+    min-width: 36px;
+    max-width: 48px;
+    text-align: center;
+    padding-left: 0;
+    padding-right: 0;
+}
+
+.type-icon-cell {
+    text-align: center;
+    vertical-align: middle;
+}
+
+.dialog-type-icon {
+    font-size: 1.4em;
+    display: inline-block;
+    line-height: 1;
+    vertical-align: middle;
+}
+
 #dialog-items-table th {
-    background: #f3f7fa;
-    color: #4a90e2;
+    background: var(--bg-light);
+    color: var(--primary-blue);
     font-weight: 600;
     font-size: 1.05rem;
 }
+
 #dialog-items-table tr:last-child td {
     border-bottom: none;
 }
+
 #dialog-items-table td.actions {
-    text-align: center;
-    min-width: 90px;
+    text-align: left;
+    min-width: 110px;
+    white-space: nowrap;
 }
 
 /* Collapsible log details */
 details#generation-log-details {
     margin-bottom: 0;
     border-radius: 4px;
-    background: #f3f5f7;
-    box-shadow: 0 1px 3px rgba(44,62,80,0.04);
+    background: var(--bg-light);
+    box-shadow: 0 1px 3px var(--shadow-light);
     padding: 0 0 0 0;
     transition: box-shadow 0.15s;
 }
+
 details#generation-log-details[open] {
-    box-shadow: 0 2px 8px rgba(44,62,80,0.07);
-    background: #f9fafb;
+    box-shadow: 0 2px 8px var(--shadow-strong);
+    background: var(--bg-lighter);
 }
+
 details#generation-log-details summary {
     font-size: 1rem;
-    color: #357ab8;
+    color: var(--text-blue);
     padding: 10px 0 6px 0;
     outline: none;
 }
+
 details#generation-log-details summary:focus {
-    outline: 2px solid #4a90e2;
+    outline: 2px solid var(--primary-blue);
     border-radius: 3px;
 }
 
@@ -132,9 +240,9 @@ details#generation-log-details summary:focus {
 }
 
 .card {
-    background: #fff;
+    background: var(--bg-white);
     border-radius: 8px;
-    box-shadow: 0 2px 8px rgba(44,62,80,0.07);
+    box-shadow: 0 2px 8px var(--shadow-medium);
     padding: 18px 20px;
     margin-bottom: 18px;
 }
@@ -154,39 +262,41 @@ h2 {
     font-size: 1.5rem;
     margin-top: 0;
     margin-bottom: 16px;
-    color: #4a90e2;
+    color: var(--primary-blue);
     letter-spacing: 0.5px;
 }
 
 h3 {
     font-size: 1.1rem;
     margin-bottom: 10px;
-    color: #333;
+    color: var(--text-tertiary);
 }
 
 .x-remove-btn {
-    background: #e74c3c;
-    color: #fff;
+    background: var(--error-bg);
+    color: var(--text-white);
     border: none;
     border-radius: 50%;
-    width: 28px;
-    height: 28px;
-    font-size: 1.2rem;
+    width: 32px;
+    height: 32px;
+    font-size: 1.25rem;
     line-height: 1;
     display: inline-flex;
     align-items: center;
     justify-content: center;
     cursor: pointer;
     transition: background 0.15s;
-    margin: 0 2px;
-    box-shadow: 0 1px 2px rgba(44,62,80,0.06);
+    margin: 0 3px;
+    box-shadow: 0 1px 2px var(--shadow-light);
     outline: none;
     padding: 0;
+    vertical-align: middle;
 }
+
 .x-remove-btn:hover, .x-remove-btn:focus {
-    background: #c0392b;
-    color: #fff;
-    outline: 2px solid #e74c3c;
+    background: var(--error-bg-dark);
+    color: var(--text-white);
+    outline: 2px solid var(--error-bg);
 }
 
 .form-row {
@@ -202,9 +312,9 @@ label {
     margin-bottom: 0;
 }
 
-input[type='text'], input[type='file'] {
+input[type='text'], input[type='file'], textarea {
     padding: 8px 10px;
-    border: 1px solid #cfd8dc;
+    border: 1px solid var(--border-medium);
     border-radius: 4px;
     font-size: 1rem;
     width: 100%;
@@ -212,14 +322,21 @@ input[type='text'], input[type='file'] {
 }
 
 input[type='file'] {
-    background: #f7f7f7;
+    background: var(--bg-gray-light);
     font-size: 0.97rem;
 }
 
+.dialog-edit-textarea {
+    min-height: 60px;
+    resize: vertical;
+    font-family: inherit;
+    line-height: 1.4;
+}
+
 button {
     padding: 9px 18px;
-    background: #4a90e2;
-    color: #fff;
+    background: var(--primary-blue);
+    color: var(--text-white);
     border: none;
     border-radius: 5px;
     cursor: pointer;
@@ -229,8 +346,42 @@ button {
     margin-right: 10px;
 }
 
+.generate-line-btn, .play-line-btn {
+    background: var(--bg-blue-light);
+    color: var(--text-blue);
+    border: 1.5px solid var(--border-blue);
+    border-radius: 50%;
+    width: 32px;
+    height: 32px;
+    font-size: 1.25rem;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    margin: 0 3px;
+    padding: 0;
+    box-shadow: 0 1px 2px var(--shadow-light);
+    vertical-align: middle;
+}
+
+.generate-line-btn:disabled, .play-line-btn:disabled {
+    opacity: 0.45;
+    cursor: not-allowed;
+}
+
+.generate-line-btn.loading {
+    background: var(--warning-bg);
+    color: var(--warning-text);
+    border-color: var(--warning-border);
+}
+
+.generate-line-btn:hover, .play-line-btn:hover {
+    background: var(--bg-blue-lighter);
+    color: var(--text-blue-darker);
+    border-color: var(--text-blue);
+}
+
 button:hover, button:focus {
-    background: #357ab8;
+    background: var(--primary-blue-dark);
     outline: none;
 }
 
@@ -246,7 +397,7 @@ button:hover, button:focus {
 
 #speaker-list li {
     padding: 7px 0;
-    border-bottom: 1px solid #e3e3e3;
+    border-bottom: 1px solid var(--border-gray);
     display: flex;
     justify-content: space-between;
     align-items: center;
@@ -257,7 +408,7 @@ button:hover, button:focus {
 }
 
 pre {
-    background: #f3f5f7;
+    background: var(--bg-light);
     padding: 12px;
     border-radius: 4px;
     font-size: 0.98rem;
@@ -275,8 +426,8 @@ audio {
 #zip-archive-link {
     display: inline-block;
     margin-right: 10px;
-    color: #fff;
-    background: #4a90e2;
+    color: var(--text-white);
+    background: var(--primary-blue);
     padding: 7px 16px;
     border-radius: 4px;
     text-decoration: none;
@@ -285,17 +436,17 @@ audio {
 }
 
 #zip-archive-link:hover, #zip-archive-link:focus {
-    background: #357ab8;
+    background: var(--primary-blue-dark);
 }
 
 footer {
     text-align: center;
     padding: 20px 0;
-    background: #222e3a;
-    color: #fff;
+    background: var(--header-bg);
+    color: var(--text-white);
     margin-top: 40px;
     font-size: 1rem;
-    border-top: 3px solid #4a90e2;
+    border-top: 3px solid var(--primary-blue);
 }
 
 @media (max-width: 900px) {
@@ -328,3 +479,194 @@ footer {
         width: 100%;
     }
 }
+
+.move-up-btn, .move-down-btn {
+    background: var(--bg-blue-light);
+    color: var(--text-blue);
+    border: 1.5px solid var(--border-blue);
+    border-radius: 50%;
+    width: 32px;
+    height: 32px;
+    font-size: 1.25rem;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    margin: 0 3px;
+    padding: 0;
+    box-shadow: 0 1px 2px var(--shadow-light);
+    vertical-align: middle;
+    cursor: pointer;
+    transition: background 0.15s, color 0.15s, border-color 0.15s;
+}
+
+.move-up-btn:disabled, .move-down-btn:disabled {
+    opacity: 0.45;
+    cursor: not-allowed;
+}
+
+.move-up-btn:hover:not(:disabled), .move-down-btn:hover:not(:disabled) {
+    background: var(--bg-blue-lighter);
+    color: var(--text-blue-darker);
+    border-color: var(--text-blue);
+}
+
+.move-up-btn:focus, .move-down-btn:focus {
+    outline: 2px solid var(--primary-blue);
+    outline-offset: 2px;
+}
+
+/* TTS Settings Modal */
+.modal {
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    background-color: rgba(0, 0, 0, 0.5);
+    z-index: 1000;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+}
+
+.modal-content {
+    background: var(--bg-white);
+    border-radius: 8px;
+    box-shadow: var(--shadow-strong);
+    max-width: 500px;
+    width: 90%;
+    max-height: 80vh;
+    overflow-y: auto;
+}
+
+.modal-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    padding: 20px 24px 16px;
+    border-bottom: 1px solid var(--border-light);
+}
+
+.modal-header h3 {
+    margin: 0;
+    color: var(--text-primary);
+    font-size: 1.25rem;
+}
+
+.modal-close {
+    background: none;
+    border: none;
+    font-size: 24px;
+    cursor: pointer;
+    color: var(--text-secondary);
+    padding: 4px;
+    border-radius: 4px;
+    transition: background-color 0.2s;
+}
+
+.modal-close:hover {
+    background-color: var(--bg-light);
+}
+
+.modal-body {
+    padding: 20px 24px;
+}
+
+.settings-group {
+    margin-bottom: 20px;
+}
+
+.settings-group label {
+    display: block;
+    margin-bottom: 8px;
+    font-weight: 500;
+    color: var(--text-primary);
+}
+
+.settings-group input[type="range"] {
+    width: 100%;
+    margin-bottom: 4px;
+}
+
+.settings-group span {
+    display: inline-block;
+    min-width: 40px;
+    font-weight: 500;
+    color: var(--primary-blue);
+    margin-left: 8px;
+}
+
+.settings-group small {
+    display: block;
+    color: var(--text-secondary);
+    font-size: 0.875rem;
+    margin-top: 4px;
+    line-height: 1.3;
+}
+
+.modal-footer {
+    display: flex;
+    gap: 12px;
+    justify-content: flex-end;
+    padding: 16px 24px 20px;
+    border-top: 1px solid var(--border-light);
+}
+
+.btn-primary, .btn-secondary {
+    padding: 8px 16px;
+    border-radius: 4px;
+    border: none;
+    cursor: pointer;
+    font-size: 0.875rem;
+    font-weight: 500;
+    transition: all 0.2s;
+}
+
+.btn-primary {
+    background-color: var(--primary-blue);
+    color: var(--text-white);
+}
+
+.btn-primary:hover {
+    background-color: var(--primary-blue-dark);
+}
+
+.btn-secondary {
+    background-color: var(--bg-light);
+    color: var(--text-secondary);
+    border: 1px solid var(--border-medium);
+}
+
+.btn-secondary:hover {
+    background-color: var(--border-light);
+}
+
+/* Settings button styling */
+.settings-line-btn {
+    width: 32px;
+    height: 32px;
+    border-radius: 50%;
+    border: none;
+    background-color: var(--bg-light);
+    color: var(--text-secondary);
+    cursor: pointer;
+    font-size: 14px;
+    margin: 0 2px;
+    transition: all 0.2s;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    vertical-align: middle;
+}
+
+.settings-line-btn:hover {
+    background-color: var(--primary-blue);
+    color: var(--text-white);
+    transform: scale(1.05);
+}
+
+.settings-line-btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+    transform: none;
+}

frontend/index.html

@@ -38,12 +38,17 @@
                 <div class="dialog-controls form-row">
                     <button id="add-speech-line-btn">Add Speech Line</button>
                     <button id="add-silence-line-btn">Add Silence Line</button>
+                    <button id="generate-dialog-btn">Generate Dialog</button>
                 </div>
                 <div class="dialog-controls form-row">
                     <label for="output-base-name">Output Base Name:</label>
                     <input type="text" id="output-base-name" name="output-base-name" value="dialog_output" required>
                 </div>
-                <button id="generate-dialog-btn">Generate Dialog</button>
+                <div class="dialog-controls form-row">
+                    <button id="save-script-btn">Save Script</button>
+                    <input type="file" id="load-script-input" accept=".jsonl" style="display: none;">
+                    <button id="load-script-btn">Load Script</button>
+                </div>
             </section>
         </div>
         <!-- Results below -->
@@ -96,6 +101,40 @@
         </div>
     </footer>
 
+    <!-- TTS Settings Modal -->
+    <div id="tts-settings-modal" class="modal" style="display: none;">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h3>TTS Settings</h3>
+                <button class="modal-close" id="tts-modal-close">&times;</button>
+            </div>
+            <div class="modal-body">
+                <div class="settings-group">
+                    <label for="tts-exaggeration">Exaggeration:</label>
+                    <input type="range" id="tts-exaggeration" min="0" max="2" step="0.1" value="0.5">
+                    <span id="tts-exaggeration-value">0.5</span>
+                    <small>Controls expressiveness. Higher values = more exaggerated speech.</small>
+                </div>
+                <div class="settings-group">
+                    <label for="tts-cfg-weight">CFG Weight:</label>
+                    <input type="range" id="tts-cfg-weight" min="0" max="2" step="0.1" value="0.5">
+                    <span id="tts-cfg-weight-value">0.5</span>
+                    <small>Alignment with prompt. Higher values = more aligned with speaker characteristics.</small>
+                </div>
+                <div class="settings-group">
+                    <label for="tts-temperature">Temperature:</label>
+                    <input type="range" id="tts-temperature" min="0" max="2" step="0.1" value="0.8">
+                    <span id="tts-temperature-value">0.8</span>
+                    <small>Randomness. Lower values = more deterministic, higher = more varied.</small>
+                </div>
+            </div>
+            <div class="modal-footer">
+                <button id="tts-settings-save" class="btn-primary">Save Settings</button>
+                <button id="tts-settings-cancel" class="btn-secondary">Cancel</button>
+            </div>
+        </div>
+    </div>
+
     <script src="js/api.js" type="module"></script>
     <script src="js/app.js" type="module" defer></script>
 </body>

frontend/js/api.js

@@ -100,6 +100,27 @@ export async function deleteSpeaker(speakerId) {
 
 // ... (keep API_BASE_URL, getSpeakers, addSpeaker, deleteSpeaker)
 
+/**
+ * Generates audio for a single dialog line (speech or silence).
+ * @param {Object} line - The dialog line object (type: 'speech' or 'silence').
+ * @returns {Promise<Object>} Resolves with { audio_url } on success.
+ * @throws {Error} If the network response is not ok.
+ */
+export async function generateLine(line) {
+    const response = await fetch(`${API_BASE_URL}/dialog/generate_line/`, {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/json',
+        },
+        body: JSON.stringify(line),
+    });
+    if (!response.ok) {
+        const errorData = await response.json().catch(() => ({ message: response.statusText }));
+        throw new Error(`Failed to generate line audio: ${errorData.detail || errorData.message || response.statusText}`);
+    }
+    return response.json();
+}
+
 /**
  * Generates a dialog by sending a payload to the backend.
  * @param {Object} dialogPayload - The payload for dialog generation.

frontend/js/app.js

@@ -7,10 +7,10 @@ const API_BASE_URL = 'http://localhost:8000'; // Assuming backend runs here
 // then this should be http://localhost:8000. The backend will return paths like /generated_audio/...
 const API_BASE_URL_FOR_FILES = 'http://localhost:8000'; 
 
-document.addEventListener('DOMContentLoaded', () => {
+document.addEventListener('DOMContentLoaded', async () => {
     console.log('DOM fully loaded and parsed');
     initializeSpeakerManagement();
-    initializeDialogEditor(); // Placeholder for now
+    await initializeDialogEditor(); // Now properly awaiting the async function
     initializeResultsDisplay(); // Placeholder for now
 });
 
@@ -109,12 +109,34 @@ async function handleDeleteSpeaker(speakerId) {
 let dialogItems = []; // Holds the sequence of speech/silence items
 let availableSpeakersCache = []; // To populate speaker dropdown
 
-function initializeDialogEditor() {
+// Utility: ensure each dialog item has audioUrl, isGenerating, error
+function normalizeDialogItem(item) {
+    const normalized = {
+        ...item,
+        audioUrl: item.audioUrl || null,
+        isGenerating: item.isGenerating || false,
+        error: item.error || null
+    };
+    
+    // Add TTS settings for speech items with defaults
+    if (item.type === 'speech') {
+        normalized.exaggeration = item.exaggeration ?? 0.5;
+        normalized.cfg_weight = item.cfg_weight ?? 0.5;
+        normalized.temperature = item.temperature ?? 0.8;
+    }
+    
+    return normalized;
+}
+
+async function initializeDialogEditor() {
     const dialogItemsContainer = document.getElementById('dialog-items-container');
     const addSpeechLineBtn = document.getElementById('add-speech-line-btn');
     const addSilenceLineBtn = document.getElementById('add-silence-line-btn');
     const outputBaseNameInput = document.getElementById('output-base-name');
     const generateDialogBtn = document.getElementById('generate-dialog-btn');
+    const saveScriptBtn = document.getElementById('save-script-btn');
+    const loadScriptBtn = document.getElementById('load-script-btn');
+    const loadScriptInput = document.getElementById('load-script-input');
 
     // Results Display Elements
     const generationLogPre = document.getElementById('generation-log-content'); // Corrected ID
@@ -127,23 +149,49 @@ function initializeDialogEditor() {
     let dialogItems = [];
     let availableSpeakersCache = []; // Cache for speaker names and IDs
 
+    // Load speakers at startup
+    try {
+        availableSpeakersCache = await getSpeakers();
+        console.log(`Loaded ${availableSpeakersCache.length} speakers for dialog editor`);
+    } catch (error) {
+        console.error('Error loading speakers at startup:', error);
+        // Continue without speakers - they'll be loaded when needed
+    }
+
     // Function to render the current dialogItems array to the DOM as table rows
     function renderDialogItems() {
         if (!dialogItemsContainer) return;
         dialogItemsContainer.innerHTML = '';
+        dialogItems = dialogItems.map(normalizeDialogItem); // Ensure all fields present
         dialogItems.forEach((item, index) => {
             const tr = document.createElement('tr');
 
             // Type column
             const typeTd = document.createElement('td');
-            typeTd.textContent = item.type === 'speech' ? 'Speech' : 'Silence';
+            typeTd.classList.add('type-icon-cell');
+            if (item.type === 'speech') {
+                typeTd.innerHTML = '<span class="dialog-type-icon" title="Speech" aria-label="Speech">🗣️</span>';
+            } else {
+                typeTd.innerHTML = '<span class="dialog-type-icon" title="Silence" aria-label="Silence">🤫</span>';
+            }
             tr.appendChild(typeTd);
 
             // Speaker column
             const speakerTd = document.createElement('td');
             if (item.type === 'speech') {
-                const speaker = availableSpeakersCache.find(s => s.id === item.speaker_id);
-                speakerTd.textContent = speaker ? speaker.name : 'Unknown Speaker';
+                const speakerSelect = document.createElement('select');
+                speakerSelect.className = 'dialog-speaker-select';
+                availableSpeakersCache.forEach(speaker => {
+                    const option = document.createElement('option');
+                    option.value = speaker.id;
+                    option.textContent = speaker.name;
+                    if (speaker.id === item.speaker_id) option.selected = true;
+                    speakerSelect.appendChild(option);
+                });
+                speakerSelect.onchange = (e) => {
+                    dialogItems[index].speaker_id = e.target.value;
+                };
+                speakerTd.appendChild(speakerSelect);
             } else {
                 speakerTd.textContent = '—';
             }
@@ -151,17 +199,94 @@ function initializeDialogEditor() {
 
             // Text/Duration column
             const textTd = document.createElement('td');
+            textTd.className = 'dialog-editable-cell';
             if (item.type === 'speech') {
                 let txt = item.text.length > 60 ? item.text.substring(0, 57) + '…' : item.text;
                 textTd.textContent = `"${txt}"`;
+                textTd.title = item.text;
             } else {
                 textTd.textContent = `${item.duration}s`;
             }
+            // Double-click to edit
+            textTd.ondblclick = () => {
+                textTd.innerHTML = '';
+                let input;
+                if (item.type === 'speech') {
+                    // Use textarea for speech text to enable multi-line editing
+                    input = document.createElement('textarea');
+                    input.className = 'dialog-edit-textarea';
+                    input.value = item.text;
+                    input.rows = Math.max(2, Math.ceil(item.text.length / 50)); // Auto-size based on content
+                } else {
+                    // Use number input for duration
+                    input = document.createElement('input');
+                    input.className = 'dialog-edit-input';
+                    input.type = 'number';
+                    input.value = item.duration;
+                    input.min = 0.1;
+                    input.step = 0.1;
+                }
+                input.onblur = saveEdit;
+                input.onkeydown = (e) => {
+                    if (e.key === 'Enter' && item.type === 'silence') {
+                        // Only auto-save on Enter for duration inputs
+                        input.blur();
+                    } else if (e.key === 'Escape') {
+                        renderDialogItems();
+                    } else if (e.key === 'Enter' && e.ctrlKey && item.type === 'speech') {
+                        // Ctrl+Enter to save for speech text
+                        input.blur();
+                    }
+                };
+                textTd.appendChild(input);
+                input.focus();
+                function saveEdit() {
+                    if (item.type === 'speech') {
+                        dialogItems[index].text = input.value;
+                        dialogItems[index].audioUrl = null; // Invalidate audio if text edited
+                    } else {
+                        let val = parseFloat(input.value);
+                        if (!isNaN(val) && val > 0) dialogItems[index].duration = val;
+                        dialogItems[index].audioUrl = null;
+                    }
+                    renderDialogItems();
+                }
+            };
             tr.appendChild(textTd);
 
             // Actions column
             const actionsTd = document.createElement('td');
             actionsTd.classList.add('actions');
+
+            // Up button
+            const upBtn = document.createElement('button');
+            upBtn.innerHTML = '↑';
+            upBtn.title = 'Move up';
+            upBtn.className = 'move-up-btn';
+            upBtn.disabled = index === 0;
+            upBtn.onclick = () => {
+                if (index > 0) {
+                    [dialogItems[index - 1], dialogItems[index]] = [dialogItems[index], dialogItems[index - 1]];
+                    renderDialogItems();
+                }
+            };
+            actionsTd.appendChild(upBtn);
+
+            // Down button
+            const downBtn = document.createElement('button');
+            downBtn.innerHTML = '↓';
+            downBtn.title = 'Move down';
+            downBtn.className = 'move-down-btn';
+            downBtn.disabled = index === dialogItems.length - 1;
+            downBtn.onclick = () => {
+                if (index < dialogItems.length - 1) {
+                    [dialogItems[index], dialogItems[index + 1]] = [dialogItems[index + 1], dialogItems[index]];
+                    renderDialogItems();
+                }
+            };
+            actionsTd.appendChild(downBtn);
+
+            // Remove button
             const removeBtn = document.createElement('button');
             removeBtn.innerHTML = '&times;'; // Unicode multiplication sign (X)
             removeBtn.classList.add('remove-dialog-item-btn', 'x-remove-btn');
@@ -172,8 +297,71 @@ function initializeDialogEditor() {
                 renderDialogItems();
             };
             actionsTd.appendChild(removeBtn);
-            tr.appendChild(actionsTd);
 
+            // --- NEW: Per-line Generate button ---
+            const generateBtn = document.createElement('button');
+            generateBtn.innerHTML = '⚡';
+            generateBtn.title = 'Generate audio for this line';
+            generateBtn.className = 'generate-line-btn';
+            generateBtn.disabled = item.isGenerating;
+            if (item.isGenerating) generateBtn.classList.add('loading');
+            generateBtn.onclick = async () => {
+                dialogItems[index].isGenerating = true;
+                dialogItems[index].error = null;
+                renderDialogItems();
+                try {
+                    const { generateLine } = await import('./api.js');
+                    const payload = { ...item };
+                    // Remove fields not needed by backend
+                    delete payload.audioUrl; delete payload.isGenerating; delete payload.error;
+                    const result = await generateLine(payload);
+                    dialogItems[index].audioUrl = result.audio_url;
+                } catch (err) {
+                    dialogItems[index].error = err.message || 'Failed to generate audio.';
+                    alert(dialogItems[index].error);
+                } finally {
+                    dialogItems[index].isGenerating = false;
+                    renderDialogItems();
+                }
+            };
+            actionsTd.appendChild(generateBtn);
+
+            // --- NEW: Per-line Play button ---
+            const playBtn = document.createElement('button');
+            playBtn.innerHTML = '⏵';
+            playBtn.title = item.audioUrl ? 'Play generated audio' : 'No audio generated yet';
+            playBtn.className = 'play-line-btn';
+            playBtn.disabled = !item.audioUrl;
+            playBtn.onclick = () => {
+                if (!item.audioUrl) return;
+                let audioUrl = item.audioUrl.startsWith('http') ? item.audioUrl : `${API_BASE_URL_FOR_FILES}${item.audioUrl}`;
+                // Use a shared audio element or create one per play
+                let audio = new window.Audio(audioUrl);
+                audio.play();
+            };
+            actionsTd.appendChild(playBtn);
+
+            // --- NEW: Settings button for speech items ---
+            if (item.type === 'speech') {
+                const settingsBtn = document.createElement('button');
+                settingsBtn.innerHTML = '⚙️';
+                settingsBtn.title = 'TTS Settings';
+                settingsBtn.className = 'settings-line-btn';
+                settingsBtn.onclick = () => {
+                    showTTSSettingsModal(item, index);
+                };
+                actionsTd.appendChild(settingsBtn);
+            }
+
+            // Show error if present
+            if (item.error) {
+                const errorSpan = document.createElement('span');
+                errorSpan.className = 'line-error-msg';
+                errorSpan.textContent = item.error;
+                actionsTd.appendChild(errorSpan);
+            }
+
+            tr.appendChild(actionsTd);
             dialogItemsContainer.appendChild(tr);
         });
     }
@@ -231,7 +419,7 @@ function initializeDialogEditor() {
                     alert('Please select a speaker and enter text.');
                     return;
                 }
-                dialogItems.push({ type: 'speech', speaker_id: speakerId, text: text });
+                dialogItems.push(normalizeDialogItem({ type: 'speech', speaker_id: speakerId, text: text }));
                 renderDialogItems();
                 clearTempInputArea();
             };
@@ -273,7 +461,7 @@ function initializeDialogEditor() {
                     alert('Invalid duration. Please enter a positive number.');
                     return;
                 }
-                dialogItems.push({ type: 'silence', duration: duration });
+                dialogItems.push(normalizeDialogItem({ type: 'silence', duration: duration }));
                 renderDialogItems();
                 clearTempInputArea();
             };
@@ -301,40 +489,25 @@ function initializeDialogEditor() {
             }
             if (dialogItems.length === 0) {
                 alert('Please add at least one speech or silence line to the dialog.');
-                return;
+                return; // Prevent further execution if no dialog items
             }
 
-            // Clear previous results and show loading/status
-            if (generationLogPre) generationLogPre.textContent = 'Generating dialog...';
-            if (audioPlayer) {
-                audioPlayer.style.display = 'none';
-                audioPlayer.src = ''; // Clear previous audio source
+            // Smart dialog-wide generation: use pre-generated audio where present
+            const dialogItemsToGenerate = dialogItems.map(item => {
+                // Only send minimal fields for items that need generation
+                if (item.audioUrl) {
+                    return { ...item, use_existing_audio: true, audio_url: item.audioUrl };
+                } else {
+                    // Remove frontend-only fields
+                    const payload = { ...item };
+                    delete payload.audioUrl; delete payload.isGenerating; delete payload.error;
+                    return payload;
                 }
-            if (downloadZipLink) {
-                downloadZipLink.style.display = 'none';
-                downloadZipLink.href = '#';
-                downloadZipLink.textContent = '';
-            }
-            if (zipArchivePlaceholder) zipArchivePlaceholder.style.display = 'block'; // Show placeholder
-            if (resultsDisplaySection) resultsDisplaySection.style.display = 'block'; // Make sure it's visible
+            });
 
             const payload = {
                 output_base_name: outputBaseName,
-                dialog_items: dialogItems.map(item => {
-                    // For now, we are not collecting TTS params in the UI for speech items.
-                    // The backend will use defaults. If we add UI for these later, they'd be included here.
-                    if (item.type === 'speech') {
-                        return {
-                            type: item.type,
-                            speaker_id: item.speaker_id,
-                            text: item.text,
-                            // exaggeration: item.exaggeration, // Example for future UI enhancement
-                            // cfg_weight: item.cfg_weight,
-                            // temperature: item.temperature
-                        };
-                    }
-                    return item; // for silence items
-                })
+                dialog_items: dialogItemsToGenerate
             };
 
             try {
@@ -345,7 +518,10 @@ function initializeDialogEditor() {
                 if (generationLogPre) generationLogPre.textContent = result.log || 'No log output.';
                 
                 if (result.concatenated_audio_url && audioPlayer) { // Check audioPlayer, not audioSource
-                    audioPlayer.src = result.concatenated_audio_url.startsWith('http') ? result.concatenated_audio_url : `${API_BASE_URL_FOR_FILES}${result.concatenated_audio_url}`;
+                    // Cache-busting: append timestamp to force reload
+                    let audioUrl = result.concatenated_audio_url.startsWith('http') ? result.concatenated_audio_url : `${API_BASE_URL_FOR_FILES}${result.concatenated_audio_url}`;
+                    audioUrl += (audioUrl.includes('?') ? '&' : '?') + 't=' + Date.now();
+                    audioPlayer.src = audioUrl;
                     audioPlayer.load(); // Call load() after setting new source
                     audioPlayer.style.display = 'block';
                 } else {
@@ -372,8 +548,274 @@ function initializeDialogEditor() {
         });
     }
 
+    // --- Save/Load Script Functionality ---
+    function saveDialogScript() {
+        if (dialogItems.length === 0) {
+            alert('No dialog items to save. Please add some speech or silence lines first.');
+            return;
+        }
+
+        // Filter out UI-specific fields and create clean data for export
+        const exportData = dialogItems.map(item => {
+            const cleanItem = {
+                type: item.type
+            };
+            
+            if (item.type === 'speech') {
+                cleanItem.speaker_id = item.speaker_id;
+                cleanItem.text = item.text;
+                // Include TTS parameters if they exist (will use defaults if not present)
+                if (item.exaggeration !== undefined) cleanItem.exaggeration = item.exaggeration;
+                if (item.cfg_weight !== undefined) cleanItem.cfg_weight = item.cfg_weight;
+                if (item.temperature !== undefined) cleanItem.temperature = item.temperature;
+            } else if (item.type === 'silence') {
+                cleanItem.duration = item.duration;
+            }
+            
+            return cleanItem;
+        });
+
+        // Convert to JSONL format (one JSON object per line)
+        const jsonlContent = exportData.map(item => JSON.stringify(item)).join('\n');
+        
+        // Create and download file
+        const blob = new Blob([jsonlContent], { type: 'application/jsonl' });
+        const url = URL.createObjectURL(blob);
+        const link = document.createElement('a');
+        
+        // Generate filename with timestamp
+        const timestamp = new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19);
+        const filename = `dialog_script_${timestamp}.jsonl`;
+        
+        link.href = url;
+        link.download = filename;
+        link.style.display = 'none';
+        document.body.appendChild(link);
+        link.click();
+        document.body.removeChild(link);
+        URL.revokeObjectURL(url);
+        
+        console.log(`Dialog script saved as ${filename}`);
+    }
+
+    function loadDialogScript(file) {
+        if (!file) {
+            alert('Please select a file to load.');
+            return;
+        }
+
+        const reader = new FileReader();
+        reader.onload = async function(e) {
+            try {
+                const content = e.target.result;
+                const lines = content.trim().split('\n');
+                const loadedItems = [];
+
+                for (let i = 0; i < lines.length; i++) {
+                    const line = lines[i].trim();
+                    if (!line) continue; // Skip empty lines
+                    
+                    try {
+                        const item = JSON.parse(line);
+                        const validatedItem = validateDialogItem(item, i + 1);
+                        if (validatedItem) {
+                            loadedItems.push(normalizeDialogItem(validatedItem));
+                        }
+                    } catch (parseError) {
+                        console.error(`Error parsing line ${i + 1}:`, parseError);
+                        alert(`Error parsing line ${i + 1}: ${parseError.message}`);
+                        return;
+                    }
+                }
+
+                if (loadedItems.length === 0) {
+                    alert('No valid dialog items found in the file.');
+                    return;
+                }
+
+                // Confirm replacement if existing items
+                if (dialogItems.length > 0) {
+                    const confirmed = confirm(
+                        `This will replace your current dialog (${dialogItems.length} items) with the loaded script (${loadedItems.length} items). Continue?`
+                    );
+                    if (!confirmed) return;
+                }
+
+                // Ensure speakers are loaded before rendering
+                if (availableSpeakersCache.length === 0) {
+                    try {
+                        availableSpeakersCache = await getSpeakers();
+                    } catch (error) {
+                        console.error('Error fetching speakers:', error);
+                        alert('Could not load speakers. Dialog loaded but speaker names may not display correctly.');
+                    }
+                }
+
+                // Replace current dialog
+                dialogItems.splice(0, dialogItems.length, ...loadedItems);
+                renderDialogItems();
+                
+                console.log(`Loaded ${loadedItems.length} dialog items from script`);
+                alert(`Successfully loaded ${loadedItems.length} dialog items.`);
+                
+            } catch (error) {
+                console.error('Error loading dialog script:', error);
+                alert(`Error loading dialog script: ${error.message}`);
+            }
+        };
+        
+        reader.onerror = function() {
+            alert('Error reading file. Please try again.');
+        };
+        
+        reader.readAsText(file);
+    }
+
+    function validateDialogItem(item, lineNumber) {
+        if (!item || typeof item !== 'object') {
+            throw new Error(`Line ${lineNumber}: Invalid item format`);
+        }
+
+        if (!item.type || !['speech', 'silence'].includes(item.type)) {
+            throw new Error(`Line ${lineNumber}: Invalid or missing type. Must be 'speech' or 'silence'`);
+        }
+
+        if (item.type === 'speech') {
+            if (!item.speaker_id || typeof item.speaker_id !== 'string') {
+                throw new Error(`Line ${lineNumber}: Speech items must have a valid speaker_id`);
+            }
+            if (!item.text || typeof item.text !== 'string') {
+                throw new Error(`Line ${lineNumber}: Speech items must have text`);
+            }
+            
+            // Check if speaker exists in available speakers
+            const speakerExists = availableSpeakersCache.some(speaker => speaker.id === item.speaker_id);
+            if (availableSpeakersCache.length > 0 && !speakerExists) {
+                console.warn(`Line ${lineNumber}: Speaker '${item.speaker_id}' not found in available speakers`);
+                // Don't throw error, just warn - speaker might be added later
+            }
+            
+            return {
+                type: 'speech',
+                speaker_id: item.speaker_id,
+                text: item.text
+            };
+        } else if (item.type === 'silence') {
+            if (typeof item.duration !== 'number' || item.duration <= 0) {
+                throw new Error(`Line ${lineNumber}: Silence items must have a positive duration number`);
+            }
+            
+            return {
+                type: 'silence',
+                duration: item.duration
+            };
+        }
+    }
+
+    // Event handlers for save/load
+    if (saveScriptBtn) {
+        saveScriptBtn.addEventListener('click', saveDialogScript);
+    }
+
+    if (loadScriptBtn && loadScriptInput) {
+        loadScriptBtn.addEventListener('click', () => {
+            loadScriptInput.click();
+        });
+        
+        loadScriptInput.addEventListener('change', (e) => {
+            const file = e.target.files[0];
+            if (file) {
+                loadDialogScript(file);
+                // Reset input so same file can be loaded again
+                e.target.value = '';
+            }
+        });
+    }
+
     console.log('Dialog Editor Initialized');
     renderDialogItems(); // Initial render (empty)
+
+    // Add a function to show TTS settings modal
+    function showTTSSettingsModal(item, index) {
+        const modal = document.getElementById('tts-settings-modal');
+        const exaggerationSlider = document.getElementById('tts-exaggeration');
+        const exaggerationValue = document.getElementById('tts-exaggeration-value');
+        const cfgWeightSlider = document.getElementById('tts-cfg-weight');
+        const cfgWeightValue = document.getElementById('tts-cfg-weight-value');
+        const temperatureSlider = document.getElementById('tts-temperature');
+        const temperatureValue = document.getElementById('tts-temperature-value');
+        const saveBtn = document.getElementById('tts-settings-save');
+        const cancelBtn = document.getElementById('tts-settings-cancel');
+        const closeBtn = document.getElementById('tts-modal-close');
+
+        // Set current values
+        exaggerationSlider.value = item.exaggeration || 0.5;
+        exaggerationValue.textContent = exaggerationSlider.value;
+        cfgWeightSlider.value = item.cfg_weight || 0.5;
+        cfgWeightValue.textContent = cfgWeightSlider.value;
+        temperatureSlider.value = item.temperature || 0.8;
+        temperatureValue.textContent = temperatureSlider.value;
+
+        // Update value displays when sliders change
+        const updateValueDisplay = (slider, display) => {
+            display.textContent = slider.value;
+        };
+
+        exaggerationSlider.oninput = () => updateValueDisplay(exaggerationSlider, exaggerationValue);
+        cfgWeightSlider.oninput = () => updateValueDisplay(cfgWeightSlider, cfgWeightValue);
+        temperatureSlider.oninput = () => updateValueDisplay(temperatureSlider, temperatureValue);
+
+        // Show modal
+        modal.style.display = 'flex';
+
+        // Save settings
+        const saveSettings = () => {
+            dialogItems[index].exaggeration = parseFloat(exaggerationSlider.value);
+            dialogItems[index].cfg_weight = parseFloat(cfgWeightSlider.value);
+            dialogItems[index].temperature = parseFloat(temperatureSlider.value);
+            
+            // Clear any existing audio since settings changed
+            dialogItems[index].audioUrl = null;
+            
+            closeModal();
+            renderDialogItems(); // Re-render to reflect changes
+            console.log('TTS settings updated for item:', dialogItems[index]);
+        };
+
+        // Close modal
+        const closeModal = () => {
+            modal.style.display = 'none';
+            // Clean up event listeners
+            exaggerationSlider.oninput = null;
+            cfgWeightSlider.oninput = null;
+            temperatureSlider.oninput = null;
+            saveBtn.onclick = null;
+            cancelBtn.onclick = null;
+            closeBtn.onclick = null;
+            modal.onclick = null;
+        };
+
+        // Event listeners
+        saveBtn.onclick = saveSettings;
+        cancelBtn.onclick = closeModal;
+        closeBtn.onclick = closeModal;
+        
+        // Close modal when clicking outside
+        modal.onclick = (e) => {
+            if (e.target === modal) {
+                closeModal();
+            }
+        };
+
+        // Close modal on Escape key
+        const handleEscape = (e) => {
+            if (e.key === 'Escape') {
+                closeModal();
+                document.removeEventListener('keydown', handleEscape);
+            }
+        };
+        document.addEventListener('keydown', handleEscape);
+    }
 }
 
 // --- Results Display --- //

speaker_data/speakers.yaml

@@ -10,3 +10,12 @@
 fb84ce1c-f32d-4df9-9673-2c64e9603133:
   name: Debbie
   sample_path: speaker_samples/fb84ce1c-f32d-4df9-9673-2c64e9603133.wav
+90fcd672-ba84-441a-ac6c-0449a59653bd:
+  name: dummy_speaker
+  sample_path: speaker_samples/90fcd672-ba84-441a-ac6c-0449a59653bd.wav
+a6387c23-4ca4-42b5-8aaf-5699dbabbdf0:
+  name: Mike
+  sample_path: speaker_samples/a6387c23-4ca4-42b5-8aaf-5699dbabbdf0.wav
+6cf4d171-667d-4bc8-adbb-6d9b7c620cb8:
+  name: Minnie
+  sample_path: speaker_samples/6cf4d171-667d-4bc8-adbb-6d9b7c620cb8.wav