"""TieMeasureFlow Server Configuration."""
from pathlib import Path

from pydantic import model_validator
from pydantic_settings import BaseSettings

# Committed defaults. Fine for dev/test (SQLite in-memory, nothing exposed); a
# real deployment that still has these is running on secrets anyone can read
# in this file's git history.
_DEFAULT_SECRET_KEY = "change-this-to-a-random-secret-key"
_DEFAULT_DB_PASSWORD = "change_me_in_production"


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

    # Deployment environment. "dev" and "test" skip the production-only guard
    # below; anything else (e.g. "production") is treated as a real
    # deployment. Local dev and the test suite must keep starting with no
    # .env at all, which is why this defaults to "dev" rather than requiring
    # the variable.
    app_env: str = "dev"

    # Database
    db_host: str = "localhost"
    db_port: int = 3306
    db_name: str = "tiemeasureflow"
    db_user: str = "tmflow"
    db_password: str = _DEFAULT_DB_PASSWORD

    # Presentation time zone (DB is UTC, #42)
    display_timezone: str = "Europe/Rome"

    # Server
    server_host: str = "0.0.0.0"
    server_port: int = 8000
    server_secret_key: str = _DEFAULT_SECRET_KEY
    server_cors_origins: str = "http://localhost:5000"
    # Worker processes (e.g. `uvicorn --workers N`). Each rate-limit bucket lives
    # in process memory, so this is how RateLimitMiddleware divides the
    # configured limits to keep the cluster-wide effective limit close to what
    # was configured instead of multiplying it by N.
    web_concurrency: int = 1

    # API key session lifetime (hours); renewed on use (env API_KEY_TTL_HOURS).
    api_key_ttl_hours: int = 24
    # How many reverse proxies between the client and this API are trusted to
    # have appended their own hop to X-Forwarded-For (Nginx, in the default
    # deploy). Used by RateLimitMiddleware._client_ip. 0 disables proxy header
    # parsing entirely (only request.client.host is trusted).
    trusted_proxy_count: int = 1

    # File Storage
    upload_dir: str = "uploads"
    max_upload_size_mb: int = 50

    # Rate Limiting (requests per minute, per real client IP)
    rate_limit_login: int = 5
    rate_limit_general: int = 300

    # SSL (Production)
    ssl_certfile: str | None = None
    ssl_keyfile: str | None = None

    # Setup page (empty = disabled)
    setup_password: str | None = None
    # By default, once an admin user exists, setup's privileged endpoints
    # (reset-db, seed, manage-user, change-user-password, init-db) refuse to
    # run again. Set true for scripted re-provisioning of a demo/test deploy.
    setup_allow_after_init: bool = False

    # AI / OpenRouter (for technical sheet parsing)
    openrouter_api_key: str | None = None
    openrouter_model: str = "anthropic/claude-sonnet-4"

    # Vision worker (internal network only, reachable as `vision` in Compose)
    vision_worker_url: str = "http://vision:8100"

    @property
    def database_url(self) -> str:
        """Async MySQL connection string."""
        return (
            f"mysql+asyncmy://{self.db_user}:{self.db_password}"
            f"@{self.db_host}:{self.db_port}/{self.db_name}"
        )

    @property
    def cors_origins(self) -> list[str]:
        """Parse CORS origins from comma-separated string."""
        return [origin.strip() for origin in self.server_cors_origins.split(",")]

    @property
    def upload_path(self) -> Path:
        """Absolute path to upload directory.

        After the V2.0.0 restructure, uploads live at the project root
        (mounted as a Docker volume), not inside the backend tree.
        """
        # Path(__file__) = src/backend/config.py → parents[2] = project root
        return Path(__file__).resolve().parents[2] / self.upload_dir

    # Always resolve .env against the project root regardless of cwd
    # (pydantic-settings would otherwise treat the path as cwd-relative).
    model_config = {
        "env_file": str(Path(__file__).resolve().parents[2] / ".env"),
        "env_file_encoding": "utf-8",
        "extra": "ignore",
    }

    @model_validator(mode="after")
    def _refuse_default_secrets_outside_dev(self) -> "Settings":
        """Refuse to boot with a committed default secret in a real deployment.

        Only fires when APP_ENV names an actual deployment (not "dev"/"test"),
        so local development and the test suite keep starting with no .env at
        all.
        """
        if self.app_env in ("dev", "test"):
            return self
        if self.server_secret_key == _DEFAULT_SECRET_KEY:
            raise RuntimeError(
                "SERVER_SECRET_KEY is still the committed default value; "
                "set it before running with APP_ENV=" + self.app_env
            )
        if self.db_password == _DEFAULT_DB_PASSWORD:
            raise RuntimeError(
                "DB_PASSWORD is still the committed default value; "
                "set it before running with APP_ENV=" + self.app_env
            )
        return self


settings = Settings()