"""
Application configuration using Pydantic Settings.

Loads configuration from environment variables with validation.
"""

from typing import Literal, List, Union

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    """Application settings loaded from environment variables."""

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=False,
    )

    # Database
    DATABASE_URL: str = Field(
        default="postgresql+asyncpg://postgres:postgres@localhost:5432/irt_bank_soal",
        description="PostgreSQL database URL with asyncpg driver",
    )

    # FastAPI
    SECRET_KEY: str = Field(
        default="dev-secret-key-change-in-production",
        description="Secret key for JWT token signing",
    )
    API_V1_STR: str = Field(default="/api/v1", description="API v1 prefix")
    PROJECT_NAME: str = Field(default="IRT Bank Soal", description="Project name")
    ENVIRONMENT: Literal["development", "staging", "production"] = Field(
        default="development", description="Environment name"
    )

    # OpenRouter (AI Generation)
    OPENROUTER_API_KEY: str = Field(
        default="", description="OpenRouter API key for AI generation"
    )
    OPENROUTER_MODEL_QWEN: str = Field(
        default="qwen/qwen-2.5-coder-32b-instruct",
        description="Qwen model identifier",
    )
    OPENROUTER_MODEL_LLAMA: str = Field(
        default="meta-llama/llama-3.3-70b-instruct",
        description="Llama model identifier",
    )
    OPENROUTER_TIMEOUT: int = Field(default=30, description="OpenRouter API timeout in seconds")

    # WordPress Integration
    WORDPRESS_API_URL: str = Field(
        default="", description="WordPress REST API base URL"
    )
    WORDPRESS_AUTH_TOKEN: str = Field(
        default="", description="WordPress JWT authentication token"
    )

    # Redis (Celery)
    REDIS_URL: str = Field(
        default="redis://localhost:6379/0", description="Redis connection URL"
    )
    CELERY_BROKER_URL: str = Field(
        default="redis://localhost:6379/0", description="Celery broker URL"
    )
    CELERY_RESULT_BACKEND: str = Field(
        default="redis://localhost:6379/0", description="Celery result backend URL"
    )

    # CORS - stored as list, accepts comma-separated string from env
    ALLOWED_ORIGINS: List[str] = Field(
        default=["http://localhost:3000"],
        description="List of allowed CORS origins",
    )

    @field_validator("ALLOWED_ORIGINS", mode="before")
    @classmethod
    def parse_allowed_origins(cls, v: Union[str, List[str]]) -> List[str]:
        """Parse comma-separated origins into list."""
        if isinstance(v, str):
            return [origin.strip() for origin in v.split(",") if origin.strip()]
        return v


# Global settings instance
_settings: Union[Settings, None] = None


def get_settings() -> Settings:
    """
    Get application settings instance.

    Returns:
        Settings: Application settings

    Raises:
        ValueError: If settings not initialized
    """
    global _settings
    if _settings is None:
        _settings = Settings()
    return _settings


def init_settings(settings: Settings) -> None:
    """
    Initialize settings with custom instance (useful for testing).

    Args:
        settings: Settings instance to use
    """
    global _settings
    _settings = settings