# Coqui XTTS v2 Implementation Plan

## Objective
Implement Coqui XTTS v2 (`tts_models/multilingual/multi-dataset/xtts_v2`) as a new engine in AudioEngineHub.

## 1. Dependencies (`requirements.txt`)
- Add `TTS` (Coqui TTS).
- **Note:** This is a heavy library. We will add it to `requirements.txt`.
- **Potential Conflict:** `TTS` often requires specific `torch` versions. We need to ensure it plays nicely with `f5-tts` (which also uses torch) and `kokoro`.

## 2. Configuration (`app/config.py` & `.env`)
- `XTTS_DEVICE`: "cuda" or "cpu" (default: "cuda")
- `XTTS_ACCEPT_LICENSE`: "true" (required to use the model)
- `XTTS_MODEL_VERSION`: "v2.0.2" (or "main" for latest)

## 3. Engine Implementation (`app/engines/xtts.py`)
- **Class:** `XTTSEngine` (inherits `TTSEngineBase`)
- **Init:**
    - Load `TTS` API.
    - Download/Load model: `tts_models/multilingual/multi-dataset/xtts_v2`.
    - Handle license agreement.
- **Synthesize:**
    - Inputs: `text`, `speaker` (voice cloning reference), `language`.
    - **Voice Cloning:** The `speaker` argument will be interpreted as a filename in `app/asset/voices/` (or a default provided sample).
    - **Language:** XTTS supports 17 languages. We will map them (e.g., "en", "de", "fr").
- **List Models:** Return `['xtts_v2']`.
- **List Voices:** Scan `app/asset/voices/` for `.wav` files to use as reference speakers.

## 4. System Updates
- **`app/main.py`**: Register `xtts` in `ALL_ENGINES`.
- **`Dockerfile`**: Ensure system dependencies (already have `ffmpeg` and `espeak-ng`, which are good).

## 5. Directory Structure
- `app/asset/voices/`: Directory to store reference audio files for cloning.

## Action Plan
1.  Update `requirements.txt`.
2.  Create `app/engines/xtts.py`.
3.  Update `app/config.py`.
4.  Update `app/main.py`.