import inspect
import os
import sqlalchemy

from config import Config
from contextlib import contextmanager
from log import DEBUG
from sqlalchemy.orm import (sessionmaker, scoped_session)


class Counter:
    def __init__(self):
        self.count = 0

    def __repr__(self):
        return(f"<Counter({self.count=})>")

    def inc(self):
        self.count += 1
        return self.count

    def dec(self):
        self.count -= 1
        return self.count


MM_ENV = os.environ.get('MM_ENV', 'PRODUCTION')
testing = False

if MM_ENV == 'PRODUCTION':
    dbname = os.environ.get('MM_PRODUCTION_DBNAME', 'musicmuster_prod')
    dbuser = os.environ.get('MM_PRODUCTION_DBUSER', 'musicmuster')
    dbpw = os.environ.get('MM_PRODUCTION_DBPW', 'musicmuster')
    dbhost = os.environ.get('MM_PRODUCTION_DBHOST', 'localhost')
elif MM_ENV == 'TESTING':
    dbname = os.environ.get('MM_TESTING_DBNAME', 'musicmuster_testing')
    dbuser = os.environ.get('MM_TESTING_DBUSER', 'musicmuster_testing')
    dbpw = os.environ.get('MM_TESTING_DBPW', 'musicmuster_testing')
    dbhost = os.environ.get('MM_TESTING_DBHOST', 'localhost')
    testing = True
elif MM_ENV == 'DEVELOPMENT':
    dbname = os.environ.get('MM_DEVELOPMENT_DBNAME', 'musicmuster_dev')
    dbuser = os.environ.get('MM_DEVELOPMENT_DBUSER', 'musicmuster')
    dbpw = os.environ.get('MM_DEVELOPMENT_DBPW', 'musicmuster')
    dbhost = os.environ.get('MM_DEVELOPMENT_DBHOST', 'localhost')
else:
    raise ValueError(f"Unknown MusicMuster environment: {MM_ENV=}")

DEBUG(f"Using {dbname} database", True)
MYSQL_CONNECT = f"mysql+mysqldb://{dbuser}:{dbpw}@{dbhost}/{dbname}"

engine = sqlalchemy.create_engine(
    MYSQL_CONNECT,
    encoding='utf-8',
    echo=Config.DISPLAY_SQL,
    pool_pre_ping=True
)


@contextmanager
def Session():
    frame = inspect.stack()[2]
    file = frame.filename
    function = frame.function
    lineno = frame.lineno
    Session = scoped_session(sessionmaker(bind=engine))
    DEBUG(f"Session acquired, {file=}, {function=}, {lineno=}, {Session=}",
          True)
    yield Session
    DEBUG(" Session released", True)
    Session.commit()
    Session.close()