main.py

import sys
import csv
import os


CLIENT_TABLE = '.clients.csv'
CLIENT_SCHEMA = ['name', 'company', 'email', 'position']
clients = []


def _initialize_clients_from_storage():
    with open(CLIENT_TABLE, mode='r') as f:
        reader = csv.DictReader(f, fieldnames=CLIENT_SCHEMA)

        for row in reader:
            clients.append(row)


def _save_clients_to_storage():
    tmp_table_name = f'{CLIENT_TABLE}.tmp'
    with open(tmp_table_name, mode='w') as f:
        writer = csv.DictWriter(f, fieldnames=CLIENT_SCHEMA)
        writer.writerows(clients)

        os.remove(CLIENT_TABLE)
        os.rename(tmp_table_name, CLIENT_TABLE)


# Reusable functions
def _not_founded():
    return print('Client is not in the client\'s list')


def _get_client_field(field_name, message='What is the client {}? '):
    field = None

    while not field:
        field = input(message.format(field_name))
    return field


def _get_clients_data():
    return {
        'name': _get_client_field('name'),
        'company': _get_client_field('company'),
        'email': _get_client_field('email'),
        'position': _get_client_field('position')
    }


# Action functions
def create_client(client):
    global clients

    if client not in clients:
        clients.append(client)
    else:
        print('The client you enter is already on the client\'s list. Please try again')


def list_clients():
    for idx, client in enumerate(clients):
        print('{uid} | {name} | {company} | {email} | {position}'.format(
            uid = idx,
            name = client['name'],
            company = client['company'],
            email = client['email'],
            position = client['position']
        ))


def update_client(client_id, updated_client):
    global clients

    if len(clients) - 1 >= client_id:
        clients[client_id] = updated_client
    else:
        _not_founded()


def delete_client(client_id):
    global clients

    for idx, dummy_client in enumerate(clients):
        if idx == client_id:
            del clients[idx]
            break


def search_client(client_name):
    for client in clients:
        if client['name'] != client_name:
            continue
        else:
            return True


def _print_welcome():
    print('WELCOME TO VENTAS!')
    print('*' * 50)
    print('What would you like to do today?')
    print('[C]reate client')
    print('[L]ist clients')
    print('[U]pdate client')
    print('[D]elete client')
    print('[S]earch client')


if __name__ == '__main__':
    _initialize_clients_from_storage()
    _print_welcome()

    command = input()
    command = command.upper()

    if command == 'C':
        client = _get_clients_data()
        create_client(client)
        list_clients()
    elif command == 'L':
        list_clients()
    elif command == 'U':
        list_clients()
        client_id = int(_get_client_field('id'))
        updated_client = _get_clients_data()
        update_client(client_id, updated_client)
        list_clients()
    elif command == 'D':
        list_clients()
        client_id = int(_get_client_field('id'))
        delete_client(client_id)
        list_clients()
    elif command == 'S':
        client_name = _get_client_field('name')
        found = search_client(client_name.lower())

        if found:
            print(f'The client: {client_name.lower()} is in the client\'s list')
            list_clients()
        else:
            print(f'The client: {client_name} is not in our client\'s list')
    else:
        print('Invalid command! Please try again')

    _save_clients_to_storage()