import psycopg2
import psycopg2.extras
from flask import g, current_app


def init_db(app):
    """Test the database connection on startup."""
    try:
        conn = psycopg2.connect(app.config["DATABASE_URL"])
        conn.close()
        print(" * Database connection OK")
    except Exception as e:
        print(f" * Database connection FAILED: {e}")


def get_db():
    """Get a database connection for the current request."""
    if "db" not in g:
        g.db = psycopg2.connect(
            current_app.config["DATABASE_URL"],
            cursor_factory=psycopg2.extras.RealDictCursor,
        )
    return g.db


def close_db(exception=None):
    """Close database connection at end of request."""
    db = g.pop("db", None)
    if db is not None:
        db.close()


def query(sql, params=None):
    """Execute a SELECT query and return all rows as dicts."""
    db = get_db()
    with db.cursor() as cur:
        cur.execute(sql, params)
        return cur.fetchall()


def query_one(sql, params=None):
    """Execute a SELECT query and return one row as a dict."""
    db = get_db()
    with db.cursor() as cur:
        cur.execute(sql, params)
        return cur.fetchone()


def execute(sql, params=None):
    """Execute an INSERT/UPDATE/DELETE and commit."""
    db = get_db()
    with db.cursor() as cur:
        cur.execute(sql, params)
        db.commit()


def execute_returning(sql, params=None):
    """Execute an INSERT/UPDATE/DELETE with RETURNING and commit."""
    db = get_db()
    with db.cursor() as cur:
        cur.execute(sql, params)
        row = cur.fetchone()
        db.commit()
        return row