"""
db.py — MySQL/MariaDB connection for NetAdmin (PyMySQL).
All tables live in the shared 'netadmin' database.
Rows returned as dicts. Interface compatible with sqlite3 usage patterns.
"""

import logging
from contextlib import contextmanager
from typing import Any

import pymysql
import pymysql.cursors

from config import cfg

log = logging.getLogger(__name__)


class _ConnWrapper:
    """
    Thin wrapper around a PyMySQL connection that adds .execute() / .fetchone()
    / .fetchall() methods directly on the connection object — matching the sqlite3
    interface used throughout the codebase.
    """

    def __init__(self, conn):
        self._conn = conn
        self._cur  = conn.cursor()

    # ── Cursor proxy ─────────────────────────────────────────────────────
    def execute(self, sql: str, params=None):
        self._cur.execute(sql, params or ())
        return self._cur

    def fetchone(self):
        return self._cur.fetchone()

    def fetchall(self):
        return self._cur.fetchall()

    # ── Transaction proxy ─────────────────────────────────────────────────
    def commit(self):
        self._conn.commit()

    def rollback(self):
        self._conn.rollback()

    def close(self):
        try:
            self._cur.close()
        except Exception:
            pass
        self._conn.close()


def _connect() -> _ConnWrapper:
    db = cfg.database
    raw = pymysql.connect(
        host        = db.host,
        port        = db.port,
        user        = db.user,
        password    = db.password,
        database    = db.name,
        charset     = "utf8mb4",
        cursorclass = pymysql.cursors.DictCursor,
        autocommit  = False,
    )
    return _ConnWrapper(raw)


@contextmanager
def get_db():
    """Yield a connection wrapper. Commits on success, rolls back on exception."""
    conn = _connect()
    try:
        yield conn
        conn.commit()
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()


# ── Datetime helper ────────────────────────────────────────────────────────

def _dt(v) -> str | None:
    """Convert datetime/date → ISO string. Pass str/None through unchanged.
    
    MariaDB returns DATETIME columns as datetime.datetime objects via PyMySQL.
    Pydantic models expect str for these fields.
    """
    import datetime as _datetime
    if v is None:
        return None
    if isinstance(v, (_datetime.datetime, _datetime.date)):
        return v.isoformat()
    return str(v) if v else None