import sqlalchemy
import re
from helpers import *

exit_commands = ['exit', 'abort', 'quit', 'bye', 'eat flaming death']
help_commands = ['help', '?']
context_commands = ['what', '??']
local_help_commands = ['help!', '???']

class ExitMenu(Exception):
	pass

class Menu():
	def __init__(self, name, items=[], prompt='> ',
		     return_index=True,
		     exit_msg=None, exit_confirm_msg=None,
		     help_text=None):
		self.name = name
		self.items = items
		self.prompt = prompt
		self.return_index = return_index
		self.exit_msg = exit_msg
		self.exit_confirm_msg = exit_confirm_msg
		self.help_text = help_text
		self.context = None
		self.header_format = '[%s]'

	def exit_menu(self):
		if self.exit_confirm_msg != None:
			if not confirm(self.exit_confirm_msg):
				return
		raise ExitMenu()

	def at_exit(self):
		if self.exit_msg:
			print self.exit_msg

	def set_context(self, string, display=True):
		self.context = string
		if self.context != None and display:
			print self.context

	def printc(self, string):
		print string
		if self.context == None:
			self.context = string
		else:
			self.context += '\n' + string

	def show_context(self):
		print self.header_format % self.name
		if self.context != None:
			print self.context

	def item_is_submenu(self, i):
		return isinstance(self.items[i], Menu)

	def item_name(self, i):
		if self.item_is_submenu(i):
			return self.items[i].name
		elif isinstance(self.items[i], tuple):
			return self.items[i][1]
		else:
			return str(self.items[i])

	def item_value(self, i):
		if isinstance(self.items[i], tuple):
			return self.items[i][0]
		if self.return_index:
			return i
		return self.items[i]

	def input_str(self, prompt=None, regex=None, length_range=(None,None),
		      empty_string_is_none=False):
		if regex != None:
			while True:
				result = self.input_str(prompt, length_range=length_range)
				if re.match(regex+'$', result):
					return result
				else:
					print 'Value must match regular expression "%s"' % regex
		if length_range != (None,None):
			while True:
				result = self.input_str(prompt)
				length = len(result)
				if ((length_range[0] and length < length_range[0]) or
				    (length_range[1] and length > length_range[1])):
					if length_range[0] and length_range[1]:
						print 'Value must have length in range [%d,%d]' % length_range
					elif allowed_range[0]:
						print 'Value must have length at least %d' % length_range[0]
					else:
						print 'Value must have length at most %d' % length_range[1]
				else:
					return result
		if prompt == None:
			prompt = self.prompt
		while True:
			try:
				result = raw_input(prompt)
			except EOFError:
				print 'quit'
				self.exit_menu()
				continue
			if result in exit_commands:
				self.exit_menu()
				continue
			if result in help_commands:
				self.general_help()
				continue
			if result in local_help_commands:
				self.local_help()
				continue
			if result in context_commands:
				self.show_context()
				continue
			if empty_string_is_none and result == '':
				return None
			return result

	def input_int(self, prompt=None, allowed_range=(None,None)):
		if prompt == None:
			prompt = self.prompt
		while True:
			result = self.input_str(prompt)
			try:
				value = int(result)
				if ((allowed_range[0] and value < allowed_range[0]) or
				    (allowed_range[1] and value > allowed_range[1])):
					if allowed_range[0] and allowed_range[1]:
						print 'Value must be in range [%d,%d]' % allowed_range
					elif allowed_range[0]:
						print 'Value must be at least %d' % allowed_range[0]
					else:
						print 'Value must be at most %d' % allowed_range[1]
				else:
					return value
			except ValueError:
				print 'Please enter an integer'

	def input_user(self, prompt=None):
		user = None
		while user == None:
			user = retrieve_user(self.input_str(prompt),
					     self.session)
		return user

	def input_product(self, prompt=None):
		product = None
		while product == None:
			product = retrieve_product(self.input_str(prompt),
						   self.session)
		return product

	def input_thing(self, prompt=None, permitted_things=('user','product'),
			empty_input_permitted=False):
		result = None
		while result == None:
			search_str = self.input_str(prompt)
			if search_str == '' and empty_input_permitted:
				return None
			result = self.search_for_thing(search_str, permitted_things)
		return result

	def search_for_thing(self, search_str, permitted_things=('user','product')):
		search_fun = {'user': search_user,
			      'product': search_product}
		results = {}
		result_values = {}
		for thing in permitted_things:
			results[thing] = search_fun[thing](search_str, self.session)
			result_values[thing] = self.search_result_value(results[thing])
		selected_thing = argmax(result_values)
		return search_ui2(search_str, results[selected_thing],
				  selected_thing, self.session)

	def search_result_value(self, result):
		if result == None:
			return 0
		if not isinstance(result, list):
			return 3
		if len(result) == 0:
			return 0
		if len(result) == 1:
			return 2
		return 1

	def print_header(self):
		print
		print self.header_format % self.name

	def pause(self):
		self.input_str('.')

	def general_help(self):
		print '''
DIBBLER HELP

The following commands are recognized (almost) everywhere:

 help, ?          -- display this help
 what, ??         -- redisplay the current context
 help!, ???       -- display context-specific help (if any)
 exit, quit, etc. -- exit from the current menu

When prompted for a user, you can type (parts of) the user name or
card number.  When prompted for a product, you can type (parts of) the
product name or barcode.
'''

	def local_help(self):
		if self.help_text == None:
			print 'no help here'
		else:
			print 'Help for %s' % (self.header_format%self.name)
			print
			print self.help_text

	def execute(self):
		try:
			return self._execute()
		except ExitMenu:
			self.at_exit()
			return None

	def _execute(self):
		while True:
			self.print_header()
			self.set_context(None)
			if len(self.items)==0:
				self.printc('(empty menu)')
				self.pause()
				return None
			for i in range(len(self.items)):
				self.printc('%d ) %s' % (i+1, self.item_name(i)))
			item_i = self.input_int(self.prompt, (1,len(self.items)))-1
			if self.item_is_submenu(item_i):
				self.items[item_i].execute()
			else:
				return self.item_value(item_i)

class Selector(Menu):
	def __init__(self, name, items=[], prompt='select> ',
		     return_index=True,
		     exit_msg=None, exit_confirm_msg=None,
		     help_text=None):
		Menu.__init__(self, name, items, prompt, return_index, exit_msg)
		self.header_format = '%s'

	def print_header(self):
		print self.header_format % self.name

	def local_help(self):
		if self.help_text == None:
			print 'This is a selection menu.  Enter one of the listed numbers, or'
			print '\'exit\' to go out and do something else.'
		else:
			print 'Help for selector (%s)' % self.name
			print
			print self.help_text


# class ChargeMenu(Menu):
# 	def __init__(self):
# 		self.name = "Add credits to a user account"

# 	def execute(self):
# 		self.session = Session()
# 		amount = self.input_int('Amount to be added> ')
# 		user = self.input_user('To user>')
# 		t = Transaction(user, -amount, 'Add '+str(amount)+' to user '+user.name)
# 		t.perform_transaction()
# 		self.session.add(t)
# 		self.session.commit()
# 		print 'Added %d kr to user %s\'s account' % (amount, user.name)
# 		print 'User %s\'s credit is now %d kr' % (user,user.credit)
# 		self.session.close()
# 		self.pause()

class TransferMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Transfer credit between users')

	def _execute(self):
		self.print_header()
		self.session = Session()
		amount = self.input_int('Transfer amount> ', (-100000,100000))
		user1 = self.input_user('From user> ')
		user2 = self.input_user('To user> ')
		t1 = Transaction(user1, amount,
				 'transfer to '+user2.name)
		t2 = Transaction(user2, -amount,
				 'transfer from '+user1.name)
		t1.perform_transaction()
		t2.perform_transaction()
		self.session.add(t1)
		self.session.add(t2)
		try:
			self.session.commit()
			print 'Transfered %d kr from %s to %s' % (amount, user1, user2)
			print 'User %s\'s credit is now %d kr' % (user1, user1.credit)
			print 'User %s\'s credit is now %d kr' % (user2, user2.credit)
		except sqlalchemy.exc.SQLAlchemyError, e:
			print 'Could not perform transfer: %s' % e
		self.session.close()
		self.pause()


class AddUserMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Add user')

	def _execute(self):
		self.print_header()
		self.session = Session()
		username = self.input_str('User name> ', User.name_re, (1,10))
		cardnum = self.input_str('Card number> ', User.card_re, (0,10))
		user = User(username, cardnum)
		self.session.add(user)
		try:
			self.session.commit()
			print 'User %s stored' % username
		except sqlalchemy.exc.IntegrityError, e:
			print 'Could not store user %s: %s' % (username,e)
		self.session.close()
		self.pause()


class EditUserMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Edit user')

	def _execute(self):
		self.print_header()
		self.session = Session()
		user = self.input_user('User> ')
		self.printc('Editing user %s' % user.name)
		user.card = self.input_str('Card number (currently "%s")> ' % user.card,
					   User.card_re, (0,10),
					   empty_string_is_none=True)
		try:
			self.session.commit()
			print 'User %s stored' % user.name
		except sqlalchemy.exc.SQLAlchemyError, e:
			print 'Could not store user %s: %s' % (user.name,e)
		self.session.close()
		self.pause()


class AddProductMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Add product')

	def _execute(self):
		self.session = Session()
		self.print_header()
		bar_code = self.input_int('Bar code> ')
		name = self.input_str('Name> ', Product.name_re, (1,30))
		price = self.input_int('Price> ', (1,100000))
		product = Product(bar_code, name, price)
		self.session.add(product)
		try:
			self.session.commit()
			print 'Product %s stored' % name
		except sqlalchemy.exc.SQLAlchemyError, e:
			print 'Could not store product %s: %s' % (name,e)
		self.session.close()
		self.pause()


class EditProductMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Edit product')

	def _execute(self):
		self.print_header()
		self.session = Session()
		product = self.input_product('Product> ')
		self.printc('Editing product %s' % product.name)
		while True:
			selector = Selector('Do what with %s?' % product.name,
					    items=[('name', 'Edit name'),
						   ('price', 'Edit price (currently %d)' % product.price),
						   ('store', 'Store')])
			what = selector.execute()
			if what == 'name':
				product.name = self.input_str('Name> ', Product.name_re, (1,30))
			elif what == 'price':
				product.price = self.input_int('Price> ', (1,100000))
			elif what == 'store':
				try:
					self.session.commit()
					print 'Product %s stored' % product.name
				except sqlalchemy.exc.SQLAlchemyError, e:
					print 'Could not store product %s: %s' % (product.name, e)					
				self.session.close()
				self.pause()
				return


class ShowUserMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Show user')

	def _execute(self):
		self.session = Session()
		self.print_header()
		user = self.input_user('User name or card number> ')
		print 'User name: %s' % user.name
		print 'Card number: %s' % user.card
		print 'Credit: %s kr' % user.credit
		self.print_transactions(user)
		self.pause()

	def print_transactions(self, user):
		limit = 10
		num_trans = len(user.transactions)
		if num_trans == 0:
			print 'No transactions'
			return
		if num_trans <= limit:
			print 'Transactions (%d):' % num_trans
		else:
			print 'Transactions (%d, showing only last %d):' % (num_trans,limit)
		for t in user.transactions[-limit:]:
			string = ' * %s: %s %d kr, ' % \
			    (t.time.strftime('%Y-%m-%d %H:%M'),
			     {True:'in', False:'out'}[t.amount<0],
			     abs(t.amount))
			if t.purchase:
				string += 'purchase ('
				string += ', '.join(map(lambda e: e.product.name,
							t.purchase.entries))
				string += ')'
			else:
				string += t.description
			print string
		

class BuyMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Buy')
		self.help_text = '''
Each purchase may contain one or more products and one or more buyers.

Enter products (by name or bar code) and buyers (by name or bar code)
in any order.  The information gathered so far is displayed after each
addition, and you can type 'what' at any time to redisplay it.

When finished, write an empty line to confirm the purchase.
'''

	def _execute(self):
		self.print_header()
		self.session = Session()
		self.purchase = Purchase()
		while True:
			self.print_purchase()
			self.printc({(False,False): 'Enter user or product identification',
				     (False,True): 'Enter user identification or more products',
				     (True,False): 'Enter product identification or more users',
				     (True,True): 'Enter more products or users, or an empty line to confirm'
				     }[(len(self.purchase.transactions) > 0,
					len(self.purchase.entries) > 0)])
			thing = self.input_thing(empty_input_permitted=True)
			if thing == None:
				if not self.complete_input():
					if confirm('Not enough information entered.  Abort purchase? (y/n) '):
						return False
					continue
				break
			if isinstance(thing, User):
				Transaction(thing, purchase=self.purchase)
			elif isinstance(thing, Product):
				PurchaseEntry(self.purchase, thing, 1)

		self.purchase.perform_purchase()
		self.session.add(self.purchase)
		try:
			self.session.commit()
		except sqlalchemy.exc.SQLAlchemyError, e:
			print 'Could not store purchase: %s' % e
		else:
			print 'Purchase stored.'
			self.print_purchase()
			for t in self.purchase.transactions:
				print 'User %s\'s credit is now %d kr' % (t.user.name, t.user.credit)
		self.session.close()
		self.pause()
		return True
		
	def complete_input(self):
		return self.purchase.is_complete()
			
	def format_purchase(self):
		self.purchase.set_price()
		transactions = self.purchase.transactions
		entries = self.purchase.entries
		if len(transactions) == 0 and len(entries) == 0:
			return None
		string = 'Purchase:'
		string += '\n buyers: '
		if len(transactions) == 0:
			string += '(empty)'
		else:
			string += ', '.join(map(lambda t: t.user.name, transactions))
		string += '\n products: '
		if len(entries) == 0:
			string += '(empty)'
		else:
			string += ', '.join(map(lambda e: '%s (%d kr)'%(e.product.name, e.product.price),
						entries))
		if len(transactions) > 1:
			string += '\n price per person: %d kr' % self.purchase.price_per_transaction()
		string += '\n total price: %d kr' % self.purchase.price
		return string

	def print_purchase(self):
		info = self.format_purchase()
		if info != None:
			self.set_context(info)


class AdjustCreditMenu(Menu): # reimplements ChargeMenu; these should be combined to one
	def __init__(self):
		Menu.__init__(self, 'Adjust credit')

	def _execute(self):
		self.print_header()
		self.session = Session()
		user = self.input_user('User> ')
		print 'User %s\'s credit is %d kr' % (user.name, user.credit)
		self.set_context('Adjusting credit for user %s' % user.name, display=False)
		amount = self.input_int('Add amount> ', (-100000,100000))
		description = self.input_str('Log message> ', length_range=(0,50))
		if description == '':
			description = 'manually adjusted credit'
		transaction = Transaction(user, -amount, description)
		transaction.perform_transaction()
		self.session.add(transaction)
		try:
			self.session.commit()
			print 'User %s\'s credit is now %d kr' % (user.name, user.credit)
		except sqlalchemy.exc.SQLAlchemyError, e:
			print 'Could not store transaction: %s' % e
		self.session.close()
		self.pause()


class ProductListMenu(Menu):
	def __init__(self):
		Menu.__init__(self, 'Product list')

	def _execute(self):
		self.print_header()
		session = Session()
		product_list = session.query(Product).all()
		line_format = '%-30s | %6s | %-15s'
		print line_format % ('name', 'price', 'bar code')
		print '---------------------------------------------------------'
		for p in product_list:
			print line_format % (p.name, p.price, p.bar_code)
		self.pause()


def dwim_search(string, session):
	typ = guess_data_type(string)
	if typ == None:
		print 'This does not make sense'
		return
	retriever = {'card': retrieve_user,
		     'username': retrieve_user,
		     'bar_code': retrieve_product,
		     'product_name': retrieve_product}
	value_type = {'card': 'user',
		      'username': 'user',
		      'bar_code': 'product',
		      'product_name': 'product'}
	value = retriever[typ](string, session)
# 	if value == None:
# 		print 'Input "%s" interpreted as %s; no matching %s found.' \
# 		      % (string, typ, value_type[typ])
	return (value_type[typ], value)

def search_ui(search_fun, search_str, thing, session):
	result = search_fun(search_str, session)
	return search_ui2(search_str, result, thing, session)

def search_ui2(search_str, result, thing, session):
	if not isinstance(result, list):
		return result
	if len(result) == 0:
		print 'No %ss matching "%s"' % (thing, search_str)
		return None
	if len(result) == 1:
		msg = 'One %s matching "%s": %s.  Use this? (y/n) ' %\
		      (thing, search_str, result[0])
		if confirm(msg):
			return result[0]
		return None
	limit = 9
	if len(result) > limit:
		select_header = '%d %ss matching "%s"; showing first %d' % \
		    (len(result), thing, search_str, limit)
		select_items = result[:limit]
	else:
		select_header = '%d %ss matching "%s"' % \
		    (len(result), thing, search_str)
		select_items = result
	selector = Selector(select_header, items=select_items,
			    return_index=False)
	return selector.execute()

def retrieve_user(search_str, session):
	return search_ui(search_user, search_str, 'user', session)
def retrieve_product(search_str, session):
	return search_ui(search_product, search_str, 'product', session)


#main = MainMenu()
main = Menu('Dibbler main menu',
	    items=[BuyMenu(), ProductListMenu(), ShowUserMenu(),
		   AdjustCreditMenu(), TransferMenu(),
		   Menu('Add/edit',
			items=[AddUserMenu(), EditUserMenu(),
			       AddProductMenu(), EditProductMenu()])
		   ],
	    exit_msg='happy happy joy joy',
	    exit_confirm_msg='Really quit Dibbler? (y/n) ')
main.execute()