from os import environ
from collections import namedtuple
import pg8000

from flask import g

DBResult = namedtuple('Result', 'rows rowcount')

def db():
    if not hasattr(g, 'db_connection'):
        g.db_connection = pg8000.connect(
            database=environ['DB_NAME'],
            user=environ['DB_USER'],
            password=environ['DB_PASSWORD'],
        )

    return g.db_connection

def query(query, **params):
    try:
        cursor = db().cursor()
        cursor.paramstyle = "named"
        cursor.execute(query, params)
        db().commit()

        if cursor._cached_rows:
            columns = [x[0] for x in cursor.description]
            rows = [dict(zip(columns, row)) for row in cursor.fetchall()]
            # rdef = namedtuple('row', ' '.join([x[0] for x in cursor.description]))
            # rows = list(map(rdef._make, cursor.fetchall()))
        else:
            rows = []

        return DBResult(
            rows=rows,
            rowcount=cursor.rowcount,
        )
    except:
        db().rollback()
        raise