from math import ceil

import sqlalchemy
from db import Product, User, Transaction, PurchaseEntry, Purchase
from text_interface.helpermenus import Menu


class AddStockMenu(Menu):
    def __init__(self):
        Menu.__init__(self, 'Add stock and adjust credit', uses_db=True)
        self.help_text = '''
Enter what you have bought for PVVVV here, along with your user name and how
much money you're due in credits for the purchase when prompted.\n'''
        self.users = []
        self.users = []
        self.products = {}
        self.price = 0

    def _execute(self):
        questions = {
            (False, False): 'Enter user id or a string of the form "<number> <product>"',
            (False, True): 'Enter user id or more strings of the form "<number> <product>"',
            (True, False): 'Enter a string of the form "<number> <product>"',
            (True, True): 'Enter more strings of the form "<number> <product>", or an empty line to confirm'
        }

        self.users = []
        self.products = {}
        self.price = 0

        while True:
            self.print_info()
            self.printc(questions[bool(self.users), bool(len(self.products))])
            thing_price = 0

            # Read in a 'thing' (product or user):
            line = self.input_multiple(add_nonexisting=('user', 'product'), empty_input_permitted=True,
                                       find_hidden_products=False)

            if line:
                (thing, amount) = line

                if isinstance(thing, Product):
                    self.printc(f"{amount:d} of {thing.name} registered")
                    thing_price = self.input_int('What did you pay a piece? ', (1, 100000),
                                                 default=thing.price) * amount
                    self.price += thing_price

                # once we get something in the
                # purchase, we want to protect the
                # user from accidentally killing it
                self.exit_confirm_msg = 'Abort transaction?'
            else:
                if not self.complete_input():
                    if self.confirm('Not enough information entered. Abort transaction?', default=True):
                        return False
                    continue
                break

            # Add the thing to the pending adjustments:
            self.add_thing_to_pending(thing, amount, thing_price)

        self.perform_transaction()

    def complete_input(self):
        return bool(self.users) and len(self.products) and self.price

    # TODO: Rewrite this madness
    def print_info(self):
        print((6 + Product.name_length) * '-')
        if self.price:
            print("Amount to be credited: {{0:>{0}d}}".format(Product.name_length-17).format(self.price))
        if self.users:
            print("Users to credit:")
            for user in self.users:
                print(f"  {str(user.name)}")
        print("\n{{0:s}}{{1:>{0}s}}".format(Product.name_length-1).format("Product", "Amount"))
        print((6 + Product.name_length) * '-')
        if len(self.products):
            for product in list(self.products.keys()):
                print('{{0:<{0}}}{{1:>6d}}'.format(Product.name_length).format(product.name, self.products[product][0]))
                print((6 + Product.name_length) * '-')

    def add_thing_to_pending(self, thing, amount, price):
        if isinstance(thing, User):
            self.users.append(thing)
        elif thing in list(self.products.keys()):
            print('Already added this product, adding amounts')
            self.products[thing][0] += amount
            self.products[thing][1] += price
        else:
            self.products[thing] = [amount, price]

    def perform_transaction(self):
        print('Did you pay a different price?')
        if self.confirm('>', default=False):
            price = self.input_int('How much did you pay?', default=self.price)
            # TODO: Loop until we get a valid answer instead of assuming default
            if price > self.price:
                print('Illegal action, total can not be higher than your total.')
            else:
                self.price = price

        description = self.input_str('Log message', length_range=(0, 50))
        if description == '':
            description = 'Purchased products for PVVVV, adjusted credit ' + str(self.price)
        for product in self.products:
            value = max(product.stock, 0) * product.price + self.products[product][1]
            old_price = product.price
            old_hidden = product.hidden
            product.price = int(ceil(float(value) / (max(product.stock, 0) + self.products[product][0])))
            product.stock = max(self.products[product][0], product.stock + self.products[product][0])
            product.hidden = False
            print(f"New stock for {product.name}: {product.stock:d}",
                  f"- New price: {product.price}" if old_price != product.price else "",
                  "- Removed hidden status" if old_hidden != product.hidden else "")

        purchase = Purchase()
        for user in self.users:
            Transaction(user, purchase=purchase, amount=-self.price, description=description)
        for product in self.products:
            PurchaseEntry(purchase, product, -self.products[product][0])

        purchase.perform_soft_purchase(-self.price, round_up=False)
        self.session.add(purchase)

        try:
            self.session.commit()
            print("Success! Transaction performed:")
            # self.print_info()
            for user in self.users:
                print(f"User {user.name}'s credit is now {user.credit:d}")
        except sqlalchemy.exc.SQLAlchemyError as e:
            print(f'Could not perform transaction: {e}')