"""
Configuration management for The Scheduler.
Uses Pydantic BaseSettings for type-safe environment variable loading.
"""
import tomllib
from functools import lru_cache
from pathlib import Path
from pydantic_settings import BaseSettings
from pydantic import Field


def _get_version_from_pyproject() -> tuple[str, str, str]:
    """Read version info from pyproject.toml."""
    pyproject_path = Path(__file__).parent.parent / "pyproject.toml"
    if pyproject_path.exists():
        with open(pyproject_path, "rb") as f:
            data = tomllib.load(f)
            project = data.get("project", {})
            return (
                project.get("name", "the-scheduler"),
                project.get("version", "0.0.0"),
                project.get("description", ""),
            )
    return ("the-scheduler", "0.0.0", "")


_PROJECT_NAME, _PROJECT_VERSION, _PROJECT_DESCRIPTION = _get_version_from_pyproject()


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

    # Application
    app_name: str = Field(default=_PROJECT_NAME, alias="APP_NAME")
    app_version: str = Field(default=_PROJECT_VERSION, alias="APP_VERSION")
    debug: bool = Field(default=False, alias="DEBUG")
    host: str = Field(default="0.0.0.0", alias="HOST")
    port: int = Field(default=8090, alias="PORT")
    log_level: str = Field(default="INFO", alias="LOG_LEVEL")

    # Security
    scheduler_api_key: str = Field(default="dev-key-change-me", alias="SCHEDULER_API_KEY")

    # PostgreSQL
    postgres_host: str = Field(default="postgres-shared", alias="POSTGRES_HOST")
    postgres_port: int = Field(default=5432, alias="POSTGRES_PORT")
    postgres_db: str = Field(default="library_scheduler", alias="POSTGRES_DB")
    postgres_user: str = Field(default="library_scheduler_user", alias="POSTGRES_USER")
    postgres_password: str = Field(default="", alias="POSTGRES_PASSWORD")

    # Redis
    redis_host: str = Field(default="redis-shared", alias="REDIS_HOST")
    redis_port: int = Field(default=6379, alias="REDIS_PORT")
    redis_db: int = Field(default=3, alias="REDIS_DB")

    # Gitea
    gitea_url: str = Field(default="http://gitea:3000", alias="GITEA_URL")
    gitea_user: str = Field(default="library", alias="GITEA_USER")
    gitea_password: str = Field(default="", alias="GITEA_PASSWORD")
    gitea_token: str = Field(default="", alias="GITEA_TOKEN")  # API token with write:repository scope
    gitea_ssh_host: str = Field(default="gitea", alias="GITEA_SSH_HOST")
    gitea_ssh_port: int = Field(default=22, alias="GITEA_SSH_PORT")

    # Backup Configuration
    backup_retention_daily: int = Field(default=7, alias="BACKUP_RETENTION_DAILY")
    backup_retention_weekly: int = Field(default=4, alias="BACKUP_RETENTION_WEEKLY")
    backup_retention_monthly: int = Field(default=12, alias="BACKUP_RETENTION_MONTHLY")

    # Google Cloud Storage
    gcs_credentials_file: str = Field(default="", alias="GCS_CREDENTIALS_FILE")

    # Documentation Mirroring
    docs_mirror_path: str = Field(default="/docs-mirror", alias="DOCS_MIRROR_PATH")
    docs_check_interval: int = Field(default=21600, alias="DOCS_CHECK_INTERVAL")  # 6 hours

    @property
    def database_url(self) -> str:
        """PostgreSQL connection URL for APScheduler."""
        return f"postgresql://{self.postgres_user}:{self.postgres_password}@{self.postgres_host}:{self.postgres_port}/{self.postgres_db}"

    @property
    def redis_url(self) -> str:
        """Redis connection URL."""
        return f"redis://{self.redis_host}:{self.redis_port}/{self.redis_db}"

    class Config:
        env_file = ".env"
        case_sensitive = False


@lru_cache
def get_settings() -> Settings:
    """
    Get cached settings instance.
    Using lru_cache ensures we only create one Settings instance.
    """
    return Settings()