"""
--------------------------------------------------
Connect.py
[program description]
--------------------------------------------------
Author: David Djukic
ID: 160692920
Email: djuk2920@mylaurier.ca
__updated__="2019-02-05"
--------------------------------------------------
"""

# Imports
from configparser import ConfigParser
from mysql.connector import connect, Error


class Connect:
    """
    Defines an object for a database connection.
    """
    connection = None
    cursor = None

    def __init__(self, option_file):
        """
        -------------------------------------------------------
        Initialize a MySQL database connection object.
        Use: connection = Connect(option_file)
        -------------------------------------------------------
        Parameters:
            option_file - name of option file (str)
        Returns:
            A database connection object (Connect)
        -------------------------------------------------------
        option file must be of the form:
        [database]
        user = ...
        password = ...
        host = ...
        database = ...
        -------------------------------------------------------
        See sample option file at:
        https://bohr.wlu.ca/cp363/samples/dcris.txt
        -------------------------------------------------------
        """
        try:
            # Read the contents of the option file
            config = ConfigParser()
            config.read_file(open(option_file))
            # Extract the database section into a dictionary
            params = dict(config['database'])
            params['raise_on_warnings'] = True
            params['use_unicode'] = True
            params['autocommit'] = True
            # Connect to the database
            if self.connection is None:
                self.connection = connect(**params)
                self.cursor = self.connection.cursor()
        except FileNotFoundError:
            raise Exception(
                "Option file '{}' not found.".format(option_file))
        except KeyError as err:
            if 'database' not in config.sections():
                raise Exception("Option file missing section 'database'.")
            else:
                raise err
        except Error as err:
            if err.sqlstate == '28000':
                raise Exception("Invalid username or password")
            elif err.sqlstate == '42000':
                raise Exception(
                    "Database '{}' does not exist".format(params['database']))
            else:
                raise err

    def close(self):
        """
        Closes the database connection.
        """
        try:
            self.cursor.close()
            self.connection.close()
            self.connection = None
        except AttributeError:
            raise Exception("Database connection is already closed.")
        return