import time
import os
#stock list with names, prices and the corrosponding id
items = [("chocolate", "1.50", "1"), ("crisps", "0.75", "2"), ("lemonade", "1", "3")]

#def isIdValid(id):
#	ids = []
#	for i in range(len(items)):
#		ids.append(int(items[i][2]))
#	if id not in ids:
#		return False
#	return True

#checks if the id is valid
def isIdValid2(id):
	found=False
	for i in range(len(items)):
		if int(items[i][2])==id:
			found=True
			break
	return found
#checks to see if a number is a number
def checktype(id):
	try:
		int(id)
		return True
	except ValueError:
		return False
#main function
def ask():
	#lists the available items
	for i in range(len(items)):
		print("Item " + items[i][2] + ": " + items[i][0] + " : £" + items[i][1])
	print("select the item id you would wish to purchase from the list above")
	id = input()
	#checks the input and acts accordingly
	if checktype(id) == False:
		os.system('cls')
		print("you did not enter a number retry")
		time.sleep(1.5)
		os.system('cls')
		return
	else:
		id=int(id)
		if isIdValid2(id) == False:
			os.system('cls')
			print("please enter an id in the list")
			time.sleep(1.5)
			os.system('cls')
			return
	print("processing")
	time.sleep(1)
	os.system('cls')
	print("you have selected " + items[int(id) - 1][0] + " this will cost £" + items[int(id) - 1][1] + " please insert the required money")
	print("*how much money do you put in?*")
	paid = input()
	if float(paid) > float(items[int(id) - 1][1]) :
		change = round(float(paid) - float(items[int(id) - 1][1]), 3)
		print("we are dispensing your " + items[int(id) - 1][0] + " and providing you with £" + str(change) + " as change.")
		print("dispensing " + items[int(id) - 1][0])
		time.sleep(2)
		print("dispensing change")
		time.sleep(2)
		print("thanks for shopping with us")
		time.sleep(3)
		os.system('cls')
		return
	if float(paid) == round(float(items[int(id) - 1][1]), 3):
		print("we are dispensing your " + items[int(id) - 1][0])
		time.sleep(2)
		print("thanks for shopping with us")
		time.sleep(3)
		os.system('cls')
	if float(paid) < round(float(items[int(id) - 1][1]), 3):
		print("you inserted £" + str(paid) + " however the cost is £" + str(items[int(id) - 1][1]) + " so you need to pay an extra £" + str(round(float(items[int(id) - 1][1]), 3) - float(paid)))
		print("please pay the remaining amount")
		while float(paid) < round(float(items[int(id) - 1][1]), 3):
			amt = input()
			amt = round(float(amt), 3)
			paid = float(paid)
			paid += amt
			topay = round(float(items[int(id) - 1][1]), 3) - paid
			topay = round(topay, 3)
			if float(paid) < round(float(items[int(id) - 1][1]), 3):
				print("you still need to insert £" + str(topay))
		if float(paid) > float(items[int(id) - 1][1]):
			change = round(float(paid) - float(items[int(id) - 1][1]), 3)
			print("we are dispensing your " + items[int(id) - 1][0] + " and providing you with £" + str(change) + " as change.")
			print("dispensing " + items[int(id) - 1][0])
			time.sleep(2)
			print("dispensing change")
			time.sleep(2)
			print("thanks for shopping with us")
			time.sleep(3)
			os.system('cls')
			return
		print("we are dispensing your " + items[int(id) - 1][0])
		time.sleep(2)
		print("thanks for shopping with us")
		time.sleep(3)
		os.system('cls')



while True:
	ask()