"""Application configuration, sourced from environment variables (see .env.example)."""
from functools import lru_cache
from typing import Literal
from urllib.parse import quote_plus

from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env", extra="ignore")

    app_name: str = "PESCO NCR"
    app_base_url: str = "http://localhost:8080"
    log_level: str = "INFO"

    # ── Auth ────────────────────────────────────────────────────────────────
    # "entra" validates Entra ID JWTs; "dev" trusts an X-Dev-User header and
    # must never be used outside local development.
    auth_mode: Literal["entra", "dev"] = "entra"
    entra_tenant_id: str = ""
    entra_client_id: str = ""
    entra_client_secret: str = ""
    entra_allowed_group_id: str = ""
    entra_api_audience: str = ""
    initial_admin_emails: str = ""

    # ── Database ────────────────────────────────────────────────────────────
    # Full SQLAlchemy URL override (used by tests); otherwise assembled from
    # the MYSQL_* parts below.
    database_url: str = ""
    mysql_host: str = "mysql"
    mysql_port: int = 3306
    mysql_database: str = "pesco_ncr"
    mysql_user: str = "ncr_app"
    mysql_password: str = ""

    # ── Attachments ─────────────────────────────────────────────────────────
    attachments_dir: str = "/data/attachments"
    max_upload_mb: int = 25

    # ── Notifications ───────────────────────────────────────────────────────
    notifications_enabled_default: bool = True

    # ── Job lookup (future VISUAL integration) ──────────────────────────────
    job_lookup_provider: Literal["null", "visual"] = "null"
    visual_db_host: str = ""
    visual_db_port: int = 1433
    visual_db_name: str = ""
    visual_db_user: str = ""
    visual_db_password: str = ""
    visual_site_id: str = ""

    seed_demo_data: bool = False

    @property
    def effective_database_url(self) -> str:
        if self.database_url:
            return self.database_url
        return (
            f"mysql+aiomysql://{quote_plus(self.mysql_user)}:{quote_plus(self.mysql_password)}"
            f"@{self.mysql_host}:{self.mysql_port}/{self.mysql_database}?charset=utf8mb4"
        )

    @property
    def sync_database_url(self) -> str:
        """Synchronous-driver URL for Alembic."""
        return self.effective_database_url.replace("+aiomysql", "+pymysql").replace(
            "+aiosqlite", ""
        )

    @property
    def api_audiences(self) -> list[str]:
        if self.entra_api_audience:
            return [self.entra_api_audience]
        return [f"api://{self.entra_client_id}", self.entra_client_id]

    @property
    def initial_admin_email_set(self) -> set[str]:
        return {e.strip().lower() for e in self.initial_admin_emails.split(",") if e.strip()}

    @property
    def max_upload_bytes(self) -> int:
        return self.max_upload_mb * 1024 * 1024


@lru_cache
def get_settings() -> Settings:
    return Settings()