import configparser
import psycopg2
from collections import namedtuple

Person = namedtuple("Person", ["id", "name", "surname"])
DatabaseConfig = namedtuple("Config", ["dbname", "user", "password", "host",
  "port"])


class MyDatabase(object):
    _INSERT_QUERY_TEMPLATE = "INSERT INTO mytable (name, surname) VALUES (%s, %s)"
    _SELECT_QUERY = "SELECT id, name, surname FROM mytable"
    _UPDATE_QUERY_TEMPLATE = "UPDATE mytable SET surname = %s WHERE name = %s)"
    _DELETE_QUERY_TEMPLATE = "DELETE FROM mytable WHERE name = %s"

    def __init__(self, config):
      self._config = config

    def _GetConnection(self):
        return psycopg2.connect(*self._config)

    # Better to be more specific, like: InsertUser, or InsertPerson. Depends on
    # the table you insert into.
    def InsertValues(self, name, surname):
        try:
            with self._GetConnection() as conn:
                cur = conn.cursor()
                query = cur.mogrify(MyDatabase._INSERT_QUERY_TEMPLATE, (name, surname))
                cur.execute(query)
        except Exception, e:
            print "Failed to insert values:", name, surname
            print e

    def GetAllValues(self):
        try:
            with self._GetConnection() as conn:
                cur = conn.cursor()
                cur.execute(MyDatabase._SELECT_QUERY)
                return map(Person._make, cur.fetchall())
        except Exception, e:
            print "Failed to get values.", e

    def UpdateSurnameByName(self, name, surname):
        try:
            with self._GetConnection() as conn:
                cur = conn.cursor()
                query = cur.mogrify(MyDatabase._UPDATE_QUERY_TEMPLATE, surname, name)
                cur.execute(query)
        except Exception, e:
            print "Failed to update values:", name, surname
            print e

    def DeleteValuesByName(self, name):
        try:
            with self._GetConnection() as conn:
                cur = conn.cursor()
                query = cur.mogrify(MyDatabase._DELETE_QUERY_TEMPLATE, name)
                cur.execute(query)
        except Exception, e:
            print "Failed to delete values with name =", name
            print e


def printValues(values):
    for value in values:
        print value


def main():
    # TODO: read configuration with ini parser.
    config = DatabaseConfig(dbname="postgres", user="postgres",
      password="success", host="127.0.0.1", port=5432)
    db = MyDatabase(config)
    db.InsertValues(name='John', surname='McRead')
    printValues(db.GetAllValues())

    db.UpdateSurnameByName(name='John', surname='McDonald')
    printValues(db.GetAllValues())

    db.DeleteValuesByName('John')
    printValues(db.GetAllValues())


if __name__ == "__main__":
    main()