"""Application settings with environment variable support."""

from functools import lru_cache
from pathlib import Path
from typing import Optional

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    """Application configuration with environment variable support.

    All settings can be overridden via environment variables prefixed with AUDIOCRAFT_.
    Example: AUDIOCRAFT_API_PORT=8080
    """

    model_config = SettingsConfigDict(
        env_prefix="AUDIOCRAFT_",
        env_file=".env",
        env_file_encoding="utf-8",
        extra="ignore",
    )

    # Server Configuration
    host: str = Field(default="0.0.0.0", description="Server bind host")
    gradio_port: int = Field(default=7860, description="Gradio UI port")
    api_port: int = Field(default=8000, description="FastAPI port")

    # Paths
    data_dir: Path = Field(default=Path("./data"), description="Data directory")
    output_dir: Path = Field(default=Path("./outputs"), description="Generated audio output")
    cache_dir: Path = Field(default=Path("./cache"), description="Model cache directory")
    models_config: Path = Field(
        default=Path("./config/models.yaml"), description="Model registry config"
    )

    # VRAM Management
    comfyui_reserve_gb: float = Field(
        default=10.0, description="VRAM reserved for ComfyUI (GB)"
    )
    safety_buffer_gb: float = Field(
        default=1.0, description="Safety buffer to prevent OOM (GB)"
    )
    idle_unload_minutes: int = Field(
        default=15, description="Unload models after idle time (minutes)"
    )
    max_cached_models: int = Field(
        default=2, description="Maximum number of models to keep loaded"
    )

    # API Configuration
    api_enabled: bool = Field(default=True, description="Enable REST API")
    api_key: Optional[str] = Field(default=None, description="API key for authentication")
    api_key_required: bool = Field(default=False, description="Require API key for requests")
    api_rate_limit: int = Field(default=10, description="API rate limit per minute")
    cors_origins: list[str] = Field(
        default=["*"], description="Allowed CORS origins"
    )

    # Audio Output
    default_format: str = Field(default="wav", description="Default audio format (wav, mp3, flac)")
    sample_rate: int = Field(default=32000, description="Output sample rate")
    normalize_audio: bool = Field(default=True, description="Normalize audio output")

    # Generation Defaults
    default_duration: float = Field(default=10.0, description="Default generation duration")
    max_duration: float = Field(default=300.0, description="Maximum generation duration")
    default_batch_size: int = Field(default=1, description="Default batch size")
    max_batch_size: int = Field(default=8, description="Maximum batch size")
    max_queue_size: int = Field(default=100, description="Maximum generation queue size")

    # Database
    database_url: str = Field(
        default="sqlite+aiosqlite:///./data/audiocraft.db",
        description="Database connection URL",
    )

    # Logging
    log_level: str = Field(default="INFO", description="Logging level")
    debug: bool = Field(default=False, description="Enable debug mode")

    # Model Management
    max_loaded_models: int = Field(default=2, description="Maximum models loaded simultaneously")

    def ensure_directories(self) -> None:
        """Create required directories if they don't exist."""
        self.data_dir.mkdir(parents=True, exist_ok=True)
        self.output_dir.mkdir(parents=True, exist_ok=True)
        self.cache_dir.mkdir(parents=True, exist_ok=True)
        (self.data_dir / "presets").mkdir(parents=True, exist_ok=True)

    @property
    def database_path(self) -> Path:
        """Extract database file path from URL."""
        if self.database_url.startswith("sqlite"):
            # Handle both sqlite:/// and sqlite+aiosqlite:///
            path = self.database_url.split("///")[-1]
            return Path(path)
        raise ValueError("Only SQLite databases are supported")


@lru_cache
def get_settings() -> Settings:
    """Get cached settings instance."""
    return Settings()