import os
import psycopg2
from psycopg2.extras import RealDictCursor
from urllib.parse import urlparse


class DataBase():
    def __init__(self, app):
        db_url = urlparse(os.environ['DATABASE_URL'])

        self.conn = psycopg2.connect(
            database=db_url.path[1:],
            user=db_url.username,
            password=db_url.password,
            host=db_url.hostname,
            port=db_url.port
        )

    def execute(self, query, args=(), one=False, commit=False):
        cur = self.conn.cursor(cursor_factory=RealDictCursor)
        cur.execute(query, args)
        rv = None
        if cur.description is not None:
            rv = cur.fetchall()
        if commit:
            try:
                self.conn.commit()
            except:
                self.conn.rollback()
        cur.close()

        return (rv[0] if rv else None) if one else rv

    def insert_cadence(self, rpm, device_id):
        self.execute('INSERT INTO cadence (rpm, device_id) VALUES (%s, %s)',
                     [rpm, device_id], commit=True)

    def get_all_cadences(self):
        return self.execute('SELECT * FROM cadence')