TPOPPractical5.py

#!/usr/bin/env python2

import cPickle as pickle

class Member:
	def __init__(self, firstname, surname, postcode, owned_items):
		self.firstname = firstname
		self.surname = surname
		self.postcode = postcode
		self.owned_items = owned_items
		self.ident = firstname + surname + postcode.replace(" ", "")

	def __repr__(self):
		return '<%s: %s : %s %s, %s, %s>' % (
			self.__class__.__name__, self.ident, self.firstname,
			self.surname, self.postcode, self.owned_items)

	def to_JSON(self):
		return json.dumps(self, default=lambda o: o.__dict__, sort_keys=True, indent=4)

class Item:
	def __init__(self, title, author, media, uid, member_id):
		self.title = title
		self.author = author
		self.media = media
		self.available = (member_id == None)
		self.uid = uid
		self.member_id = member_id

	def __repr__(self):
		return '<%s: %s : %s %s, %s, %s, %s>' % (
			self.__class__.__name__, self.uid, self.title,
			self.author, self.media, self.available, self.member_id)


def SaveDict(filename, savedict):
	with open(filename, 'wb') as f:
		pickle.dump(savedict, f)

def LoadDict(filename):
	opened_dict = dict()
	try:
		with open(filename, 'rb') as f:
			opened_dict = pickle.load(f)
	finally:
		return opened_dict

def AddItem(memberid=None):
	if memberid != None and memberid not in member_list:
		print "Error: Unknown member ID"
		print "Please try again"
		return

	itemname = raw_input("What is the item's name? ")
	itemauthor = raw_input("Who wrote/produced the item? ")
	itemmedia = raw_input("What is the media type of the item? ")

	# Generate UID
	itemid = ""
	for i in xrange(500): # Arbitary limit
		itemid = itemname.replace(" ", "") + itemauthor.replace(" ", "") + str(i)
		if itemid not in item_list:
			break
	item = Item(itemname, itemauthor, itemmedia, itemid, memberid)
	item_list[itemid] = item
	print "Added item: " + str(item)
	return itemid

def AddMember():
	membername = raw_input("What is the member's name? (\"firstname surname\") ")
	names = membername.split()
	if len(names) > 2:
		print "Error: Invalid name"
		print "Please try again"
		return
	memberpost = raw_input("What is the member's postcode? ")
	if len(memberpost) > 8:
		print "Error: Invalid postcode"
		print "Please try again"
		return
	memberid =  membername.replace(" ", "") + memberpost.replace(" ", "")
	if memberid in member_list:
		print "Error: Duplicate user"
		print "Please try again"
		return

	# In case there is no surname
	if len(names) == 2:
		surname = names[1]
	else:
		surname = ""

	member = Member(names[0], surname, memberpost, [])
	member_list[memberid] = member
	print "Added member: " + str(member)

	num_items = raw_input("How many items does the user own? ")
	user_item_list = []
	i = 0
	while i < num_items:
		itemid = raw_input("Enter UID for item no. " + str(i + 1) + " ")
		if itemid not in item_list:
			new_item = raw_input("Warning: Item not in database. (create/retry) ")
			if new_item == "create":
				itemid = AddItem(memberid)
				if itemid != None:
					user_item_list.append(itemid)
				else:
					# Error entering item, try again
					i -= 1
					continue
			else:
				# Error entering item, try again
				i -= 1
				continue
		elif not item_list[itemid].available:
			print "Error: Item is unavailable"
		else:
			item_list[itemid].available = False
			user_item_list.append(itemid)
		i += 1

	member_list[memberid].owned_items = user_item_list
	return memberid

def DeleteMember():
	memberid = raw_input("Enter the member ID to delete: ")
	if memberid not in member_list:
		print "Error: Cannot delete a member that doesn't exist!"
		return
	del member_list[memberid]
	# Remove all references of the member
	for key, value in item_list:
		if value.member_id == memberid:
			value.member_id = None

def DeleteItem():
	itemid = raw_input("Enter the item ID to delete: ")
	if itemid not in item_list:
		print "Error: Cannot delete an item that doesn't exist!"
		return
	del item_list[itemid]
	# Remove all references of the item
	for key, value in member_list:
		if itemid in value.owned_items:
			value.owned_items.remove(itemid)

def BorrowItem():
	memberid = raw_input("Enter ID of member: ")
	if memberid not in member_list:
		print "Error: Unrecognised member ID"
		return

	itemid = raw_input("Enter ID of item to borrow: ")
	if itemid not in item_list:
		print "Error: Unrecognised item ID"
		return

	if not item_list[itemid].available:
		print "Error: Item is unavailable"
		return

	member_list[memberid].owned_items.append(itemid)
	item_list[itemid].available = False
	item_list[itemid].member_id = memberid

def ReturnItem():
	itemid = raw_input("Enter ID of item to return: ")
	if itemid not in item_list:
		print "Error: Unrecognised item ID"
		return
	elif item_list[itemid].available:
		print "Error: Item has not been borrowed"
		return

	for key, value in member_list:
		if itemid in value.owned_items:
			value.owned_items.remove(itemid)
	item_list[itemid].member_id = None

def ListBorrowedItems():
	memberid = raw_input("Enter ID of member: ")
	if memberid not in member_list:
		print "Error: Unrecognised member ID"
		return

	member = member_list[memberid]
	print "Member \"" + member.firstname + " " + member.surname + "\" has borrowed:"
	print str(member.owned_items)


member_list = LoadDict("members")
item_list = LoadDict("items")

print "Initial member list:\n" + str(member_list) + "\n\n"
print "Initial item list:\n" + str(item_list) + "\n"


# Dispatch dictionary
main_dict = {"addmember":AddMember, "additem":AddItem, "delmember":DeleteMember,
             "delitem":DeleteItem, "borrowitem":BorrowItem, "returnitem":ReturnItem,
             "listitem":ListBorrowedItems}
# Main loop
while(True):
	userin = raw_input("What would you like to do?\n\
	                    *addmember*		- Add a member to the database\n\
	                    *additem*		- Add an item to the database\n\
	                    *delmember*		- Delete a member from the database\n\
	                    *delitem*		- Delete an item from the database\n\
	                    *borrowitem*	- Borrow an item\n\
	                    *returnitem*	- Return an item\n\
	                    *listitem*		- List the items borrowed by a member\n\
	                    *exit*		- Exit program\n\
	                    ")
	func_call = main_dict.get(userin)
	if func_call == None:
		break

	func_call()

print "Final member list:\n" + str(member_list) + "\n\n"
print "Final item list:\n" + str(item_list) + "\n"

SaveDict("members", member_list)
SaveDict("items", item_list)