app/config.py

"""
Runtime configuration for the voice-cloning app.

All values come from environment variables. Nothing is hard-coded except
the canonical language catalogue (see LANGUAGE_CATALOG) which defines the
UI-level language options we want to expose; the backend `/languages`
endpoint is still queried at startup and the intersection is used.
"""
from __future__ import annotations

import os
from dataclasses import dataclass, field
from pathlib import Path
from typing import Dict

# Load .env from the repo root (or current working directory) before any
# os.getenv() calls in this module run. Silent no-op if python-dotenv isn't
# installed or .env is absent.
try:
    from dotenv import load_dotenv as _load_dotenv

    # Look for .env walking up from this file's directory first, then CWD.
    _here = Path(__file__).resolve().parent
    for _candidate in [_here.parent / ".env", _here / ".env", Path.cwd() / ".env"]:
        if _candidate.is_file():
            _load_dotenv(_candidate, override=False)
            break
    else:
        # Fallback: let python-dotenv use its own search (walks up from CWD).
        _load_dotenv(override=False)
except ImportError:
    pass


# ---------------------------------------------------------------------------
# Canonical language catalogue
# ---------------------------------------------------------------------------
# Maps ISO-639 codes used by our UI to a (native name, english name, provider-
# hint) triple. `provider_hint` indicates which backend natively handles the
# language:
#   - "chatterbox": native in Chatterbox Multilingual (23 langs).
#   - "minimax":    only served cleanly by MiniMax (language_boost=Chinese,Yue).
# The client auto-routes per hint.
#
# Cantonese (yue) is intentionally at the top because it is a first-class
# requirement for this project (Hong Kong users).
LANGUAGE_CATALOG: Dict[str, Dict[str, str]] = {
    "yue": {"native": "粵語 (Cantonese)",  "english": "Cantonese", "provider_hint": "minimax"},
    "en":  {"native": "English",           "english": "English",   "provider_hint": "chatterbox"},
    "zh":  {"native": "普通話 (Mandarin)", "english": "Mandarin",  "provider_hint": "chatterbox"},
    "ja":  {"native": "日本語",            "english": "Japanese",  "provider_hint": "chatterbox"},
    "ko":  {"native": "한국어",            "english": "Korean",    "provider_hint": "chatterbox"},
    "fr":  {"native": "Français",          "english": "French",    "provider_hint": "chatterbox"},
    "es":  {"native": "Español",           "english": "Spanish",   "provider_hint": "chatterbox"},
}


def _as_bool(val: str | None, default: bool = False) -> bool:
    if val is None:
        return default
    return val.strip().lower() in {"1", "true", "yes", "on"}


def _as_int(val: str | None, default: int) -> int:
    try:
        return int(val) if val is not None and val.strip() != "" else default
    except ValueError:
        return default


def _as_float(val: str | None, default: float) -> float:
    try:
        return float(val) if val is not None and val.strip() != "" else default
    except ValueError:
        return default


@dataclass
class ChatterboxProviderConfig:
    """Config for the Chatterbox-compatible HTTP backend (our Modal deploy)."""
    base_url: str = ""
    api_key: str | None = None
    default_model: str = "chatterbox-multilingual"
    timeout_seconds: int = 180

    @classmethod
    def from_env(cls) -> "ChatterboxProviderConfig":
        return cls(
            base_url=(os.getenv("CHATTERBOX_API_BASE_URL", "") or "").rstrip("/"),
            api_key=os.getenv("CHATTERBOX_API_KEY") or None,
            default_model=os.getenv("CHATTERBOX_DEFAULT_MODEL", "chatterbox-multilingual"),
            timeout_seconds=_as_int(os.getenv("CHATTERBOX_TIMEOUT_SECONDS"), 180),
        )

    @property
    def is_configured(self) -> bool:
        return bool(self.base_url)


@dataclass
class MinimaxProviderConfig:
    """Config for the MiniMax provider (Cantonese-capable)."""
    api_base_url: str = "https://api.minimax.io"
    api_key: str | None = None
    group_id: str | None = None
    default_model: str = "speech-2.8-hd"
    timeout_seconds: int = 180

    @classmethod
    def from_env(cls) -> "MinimaxProviderConfig":
        return cls(
            api_base_url=(os.getenv("MINIMAX_API_BASE_URL", "https://api.minimax.io") or "").rstrip("/"),
            api_key=os.getenv("MINIMAX_API_KEY") or None,
            group_id=os.getenv("MINIMAX_GROUP_ID") or None,
            default_model=os.getenv("MINIMAX_DEFAULT_MODEL", "speech-2.8-hd"),
            timeout_seconds=_as_int(os.getenv("MINIMAX_TIMEOUT_SECONDS"), 180),
        )

    @property
    def is_configured(self) -> bool:
        # group_id is optional for plain T2A, but api_key is mandatory.
        return bool(self.api_key)


@dataclass
class Settings:
    """Top-level settings object used by the app."""

    # Upload limits (reference audio).
    max_reference_mb: int = 25
    min_reference_seconds: float = 3.0
    recommended_reference_seconds_min: float = 10.0
    recommended_reference_seconds_max: float = 30.0
    max_reference_seconds: float = 60.0

    # Generation defaults (RESOLVED CONFLICT between notes and UI).
    # Chatterbox docs: exaggeration default 0.5 (range 0.25-2.0),
    # cfg_weight default 0.5 (range 0.0-1.0). The old report's "3.0" was
    # a documentation error. We honour the upstream-documented ranges.
    default_exaggeration: float = 0.5
    default_cfg_weight: float = 0.5
    default_temperature: float = 0.8
    exaggeration_range: tuple = (0.25, 2.0)
    cfg_weight_range: tuple = (0.0, 1.0)
    temperature_range: tuple = (0.05, 5.0)

    # Runtime behaviour.
    temp_dir: Path = field(default_factory=lambda: Path(os.getenv("TEMP_DIR", "/tmp/voice-clone-cloud")))
    retry_on_transient: bool = True
    request_retry_once: bool = True
    log_provider_errors: bool = True

    # Feature flags.
    # Watermarking: we honour the backend's default. Only disable if a
    # provider explicitly cannot install the `perth` library. The old HPC
    # build disabled it because HF Hub was offline and `perth` wasn't
    # vendored in the cluster cache — not a real runtime constraint.
    disable_watermark: bool = False

    chatterbox: ChatterboxProviderConfig = field(default_factory=ChatterboxProviderConfig.from_env)
    minimax: MinimaxProviderConfig = field(default_factory=MinimaxProviderConfig.from_env)

    # Gradio server.
    gradio_server_name: str = "0.0.0.0"
    gradio_server_port: int = 7860

    @classmethod
    def from_env(cls) -> "Settings":
        s = cls(
            max_reference_mb=_as_int(os.getenv("MAX_REFERENCE_MB"), 25),
            min_reference_seconds=_as_float(os.getenv("MIN_REFERENCE_SECONDS"), 3.0),
            max_reference_seconds=_as_float(os.getenv("MAX_REFERENCE_SECONDS"), 60.0),
            default_exaggeration=_as_float(os.getenv("DEFAULT_EXAGGERATION"), 0.5),
            default_cfg_weight=_as_float(os.getenv("DEFAULT_CFG_WEIGHT"), 0.5),
            default_temperature=_as_float(os.getenv("DEFAULT_TEMPERATURE"), 0.8),
            disable_watermark=_as_bool(os.getenv("DISABLE_WATERMARK"), False),
            gradio_server_name=os.getenv("GRADIO_SERVER_NAME", "0.0.0.0"),
            gradio_server_port=_as_int(os.getenv("GRADIO_SERVER_PORT"), 7860),
        )
        s.temp_dir.mkdir(parents=True, exist_ok=True)
        return s


# Cached singleton (lazy).
_settings: Settings | None = None


def get_settings() -> Settings:
    global _settings
    if _settings is None:
        _settings = Settings.from_env()
    return _settings


def reset_settings() -> None:
    """For tests: drop the cached settings so env changes take effect."""
    global _settings
    _settings = None