Assignment5_1.py

'''
Created on 19.5.2015

    A program which allows the user to write and read product data from a file. 
    The program should ask the user to enter product data (name, unit price and amount) 
    and write the data of each product to a separate line so that details are separated 
    By semicolon(;). For the search part the application should ask the user to enter the 
    criteria (name, unit price or amount) and search the product with the criteria equal 
    to the given value.
    
@author: e1201757
'''
import os
DB_PATH = 'product_db.txt'

def writeToFile(content, filePath):
    file = open(filePath, 'a+')
    file.write(content + '\n')
    file.close()

def readFromFile(filePath):
    if os.path.exists(filePath):
        file = open(filePath, 'r')
        content = file.read().split('\n')
        content.pop()
        productsList = []
        for product in content:
            productDict = {}
            details = product.split(';')
            productDict['name'] = details[0]
            productDict['unit_price'] = details[1]
            productDict['amount'] = details[2]
            productsList.append(productDict)
        file.close()
        return productsList
    return []
        
def inputProductsFromConsole():
    text = ''
    while True:
        print('Please enter product data (name;unit price;amount), and use \';\' to separate(enter \'q\' to quit).')
        print('For example: Apple;2;100')
        text =  input('New product:').replace(' ', '')
        if validateProduct(text):
            writeToFile(text, DB_PATH)
            input('New data have been saved. Enter \'ENTER\' to continue.')
            print('---------------------------------------')    
        elif text == 'q': 
            print('---------------------------------------')
            break
        else: 
            print('Wrong Format!')
            input('Enter \'ENTER\' to continue.')
            print('---------------------------------------')

def validateProduct(text):
    details = text.split(';')    
    if len(details) == 3:
        return True
    return False    
    
def searchProducts(criteria, value):
    productsList = readFromFile(DB_PATH)
    correctProducts = []
    print('Search Result(s):')
    for productDict in productsList:
        if productDict[criteria] == value:
            correctProducts.append(productDict)
    if correctProducts != []:
        for productDict in correctProducts:
            printProduct(productDict)
    else: print('No Product has been found!\n')
    input('Enter \'ENTER\' to continue.')
    print('---------------------------------------')
        
def showAllProducts(filePath):
    productsList = readFromFile(filePath)
    if productsList!=[]:
        for productDict in productsList:
            printProduct(productDict)
    else: print('No product has been found!\n')     
    input('Enter \'ENTER\' to continue.')  
    print('---------------------------------------') 
        
def printProduct(productDict):
    print('name: ' + productDict['name'])
    print('unit price: ' + productDict['unit_price'])
    print('amount: ' + productDict['amount'])
    print('---------------------------------------')

if __name__ == '__main__':
    while True:
        print('******Products Information System******\n\n1. Enter new product data.\n2. Search by criteria in products database \n3. Show all products infomation.\n4. Quit.\n')
        choice = input('Please select:')
        print('---------------------------------------')
        if choice == '1':
            inputProductsFromConsole()
        elif choice == '2':
            criteria = input('Enter the criteria to search(name/unit_price/amount):')
            value = input('Enter the value:')
            searchProducts(criteria, value)
        elif choice == '3':
            showAllProducts(DB_PATH)
        elif choice == '4':
            print('Bye bye!')
            break
        else:
            print('Error input! Please enter a number from 1 to 4!\n')
            print('---------------------------------------')