import os
import json
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from pydantic_settings import BaseSettings
from typing import Optional


def _resolve_db_url(env_url: str) -> str:
    """Read DB config from wizard config volume if available, else use env."""
    config_dir = os.getenv("CONFIG_DIR", "/config")
    config_file = os.getenv("CONFIG_FILE", "harborforge.json")
    config_path = os.path.join(config_dir, config_file)

    if os.path.exists(config_path):
        try:
            with open(config_path, "r") as f:
                cfg = json.load(f)
            db_cfg = cfg.get("database")
            if db_cfg:
                host = db_cfg.get("host", "mysql")
                port = db_cfg.get("port", 3306)
                user = db_cfg.get("user", "harborforge")
                password = db_cfg.get("password", "harborforge_pass")
                database = db_cfg.get("database", "harborforge")
                return f"mysql+pymysql://{user}:{password}@{host}:{port}/{database}"
        except Exception:
            pass

    return env_url


class Settings(BaseSettings):
    DATABASE_URL: str = "mysql+pymysql://harborforge:harborforge_pass@mysql:3306/harborforge"
    SECRET_KEY: str = "change-me-in-production"
    LOG_LEVEL: str = "INFO"
    ALGORITHM: str = "HS256"
    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30

    class Config:
        env_file = ".env"


settings = Settings()

# Fail fast on a weak/default JWT signing key (prevents token forgery).
_WEAK_SECRETS = {
    "change-me-in-production",
    "change_me_in_production",
    "change-me-use-openssl-rand-hex-32",
    "secret",
    "changeme",
    "",
}
if settings.SECRET_KEY in _WEAK_SECRETS or len(settings.SECRET_KEY) < 32:
    raise RuntimeError(
        "Insecure SECRET_KEY: set a strong random value "
        "(e.g. `openssl rand -hex 32`) via the SECRET_KEY env var. "
        "Refusing to start with a default/short key."
    )

# Resolve DB URL: wizard config volume > env > default
_db_url = _resolve_db_url(settings.DATABASE_URL)
engine = create_engine(_db_url, pool_pre_ping=True)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()