import os

import boto3
from requests import Session
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

from app.models import Base

from .constants import AWS_REGION


def get_db_credentials():
    """Fetch and cache DB credentials from environment or SSM Parameter Store"""
    if os.getenv("MOCK_AUTH", "").lower() == "true":
        return (
            f"postgresql://{os.getenv('DB_USER')}:{os.getenv('DB_PASSWORD')}"
            f"@{os.getenv('DB_HOST')}/{os.getenv('DB_NAME')}"
        )

    ssm = boto3.client("ssm", region_name=AWS_REGION)
    try:
        host = ssm.get_parameter(Name="/iptv-manager/DB_HOST", WithDecryption=True)[
            "Parameter"
        ]["Value"]
        user = ssm.get_parameter(Name="/iptv-manager/DB_USER", WithDecryption=True)[
            "Parameter"
        ]["Value"]
        password = ssm.get_parameter(
            Name="/iptv-manager/DB_PASSWORD", WithDecryption=True
        )["Parameter"]["Value"]
        dbname = ssm.get_parameter(Name="/iptv-manager/DB_NAME", WithDecryption=True)[
            "Parameter"
        ]["Value"]
        return f"postgresql://{user}:{password}@{host}/{dbname}"
    except Exception as e:
        raise RuntimeError(f"Failed to fetch DB credentials from SSM: {str(e)}")


# Initialize engine and session maker
engine = create_engine(get_db_credentials())
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def init_db():
    """Initialize database by creating all tables"""
    Base.metadata.create_all(bind=engine)


def get_db():
    """Dependency for getting database session"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def get_db_session() -> Session:
    """Get a direct database session (non-generator version)"""
    return SessionLocal()