import pandas
from tabulate import tabulate
from datetime import date


# Functions go here
def make_statement(statement, decoration):
    """Emphasises headings by adding decoration
    at the start and end"""

    return f"{decoration * 3} {statement} {decoration * 3}\n"


def yes_no_check(question):
    """Checks that users enter yes / no / y / n"""

    while True:

        response = input(question).lower()

        if response == "y" or response == "yes":
            return "yes"
        elif response == "n" or response == "no":
            return "no"

        print(f"Please answer yes / no (y / n)")


def instructions():
    """Displays instructions"""
    print(make_statement("Instructions", "ℹ️"))

    print('''This program will ask you for... 
    - The name of the product you are selling 
    - How many items you plan on selling 
    - The costs for each component of the product 
      (variable expenses)
    - Whether or not you have fixed expenses (if you have 
      fixed expenses, it will ask you what they are).
    - How much money you want to make (ie: your profit goal)

It will also ask you how much the recommended sales price should 
be rounded to.

The program outputs an itemised list of the variable and fixed 
expenses (which includes the subtotals for these expenses). 

Finally it will tell you how much you should sell each item for 
to reach your profit goal. 

The data will also be written to a text file which has the 
same name as your product and today's date.

    ''')


def not_blank(question):
    """Checks user response is not blank"""
    while True:
        response = input(question)

        if response != "":
            return response
        else:
            print("Sorry, this can't be blank.")


def num_check(question, num_type="float", exit_code=None):
    """Checks that response is a float / integer more than zero"""

    if num_type == "float":
        error = "Please enter a number more than 0."
    else:
        error = "Please enter an integer more than 0."

    while True:

        response = input(question)

        # check for exit code and return it if entered
        if response == exit_code:
            return response

        # check datatype is correct and that number
        # is more than zero
        try:

            if num_type == "float":
                response = float(response)
            else:
                response = int(response)

            if response > 0:
                return response
            else:
                print(error)

        except ValueError:
            print(error)


def get_expenses(exp_type, how_many=1):
    """Gets variable / fixed expenses and outputs
    panda (as a string) and a subtotal of the expenses"""

    # Lists for panda
    all_items = []
    all_amounts = []
    all_dollar_per_item = []

    # Expenses dictionary
    expenses_dict = {
        "Item": all_items,
        "Amount": all_amounts,
        "$ / Item": all_dollar_per_item
    }

    # defaults for fixed expenses
    amount = how_many   # how_many defaults to 1
    how_much_question = "How much? $"

    # loop to get expenses
    while True:

        # Get item name and check it's not blank
        item_name = not_blank("Item Name: ")

        # check users enter at least one variable expense
        if exp_type == "variable" and item_name == "xxx" and len(all_items) == 0:
            print("Oops - you have not entered anything.  "
                  "You need at least one item.")
            continue

        # end loop when users enter exit code
        elif item_name == "xxx":
            break

        # Get variable expenses item amount <enter> defaults to number of
        # products being made.
        if exp_type == "variable":

            amount = num_check(f"How many <enter for {how_many}>: ",
                               "integer", "")

            # Allow users to push <enter> to default to number of items being made
            if amount == "":
                amount = how_many

            how_much_question = "Price for one? $"

        # Get price for item (question customised depending on expense type).
        price_for_one = num_check(how_much_question, "float")

        all_items.append(item_name)
        all_amounts.append(amount)
        all_dollar_per_item.append(price_for_one)

    # make panda
    expense_frame = pandas.DataFrame(expenses_dict)

    # Calculate Cost Column
    expense_frame['Cost'] = expense_frame['Amount'] * expense_frame['$ / Item']

    # calculate subtotal
    subtotal = expense_frame['Cost'].sum()

    # Apply currency formatting to currency columns.
    add_dollars = ['Amount', '$ / Item', 'Cost']
    for var_item in add_dollars:
        expense_frame[var_item] = expense_frame[var_item].apply(currency)

    # make expense frame into a string with the desired columns
    if exp_type == "variable":
        expense_string = tabulate(expense_frame, headers='keys',
                                  tablefmt='psql', showindex=False)
    else:
        expense_string = tabulate(expense_frame[['Item', 'Cost']], headers='keys',
                                  tablefmt='psql', showindex=False)

    # return the expenses panda and subtotal
    return expense_string, subtotal


def currency(x):
    """Formats numbers as currency ($#.##)"""
    return "${:.2f}".format(x)


# Main routine goes here

# intialise variables...

# assume we have no fixed expenses for now
fixed_subtotal = 0
fixed_panda_string = ""

print(make_statement("Fund Raising Calulator", "💰"))

print()
want_instructions = yes_no_check("Do you want to see the instructions? ")
print()

if want_instructions == "yes":
    instructions()

print()

# Get product details...
product_name = not_blank("Product Name: ")
quantity_made = num_check("Quantity being made: ", "integer")

# Get variable expenses...
print("Let's get the variable expenses....")
variable_expenses = get_expenses("variable", quantity_made)

variable_panda_string = variable_expenses[0]
variable_subtotal = variable_expenses[1]

# ask user if they have fixed expenses and retrieve them
print()
has_fixed = yes_no_check("Do you have fixed expenses? ")

if has_fixed == "yes":
    fixed_expenses = get_expenses("fixed")

    fixed_panda_string = fixed_expenses[0]
    fixed_subtotal = fixed_expenses[1]

    # If the user has not entered any fixed expenses,
    # # Set empty panda to "" so that it does not display!
    if fixed_subtotal == 0:
        has_fixed = "no"
        fixed_panda_string = ""

total_expenses = variable_subtotal + fixed_subtotal
total_expenses_string = f"Total Expenses: ${total_expenses:.2f}"


# Get profit Goal here.

# strings / output area

# **** Get current date for heading and filename ****
today = date.today()

# Get day, month and year as individual strings
day = today.strftime("%d")
month = today.strftime("%m")
year = today.strftime("%Y")

# Headings / Strings...
main_heading_string = make_statement(f"Fund Raising Calculator "
                                     f"({product_name}, {day}/{month}/{year})", "=")
quantity_string = f"Quantity being made: {quantity_made}"
variable_heading_string = make_statement("Variable Expenses", "-")
variable_subtotal_string = f"Variable Expenses Subtotal: ${variable_subtotal:.2f}"

# set up strings if we have fixed costs
if has_fixed == "yes":
    fixed_heading_string = make_statement("Fixed Expenses", "-")
    fixed_subtotal_string = f"Fixed Expenses Subtotal: {fixed_subtotal:.2f}"

# set fixed cost strings to blank if we don't have fixed costs
else:
    fixed_heading_string = make_statement("You have no Fixed Expenses", "-")
    fixed_subtotal_string = "Fixed Expenses Subtotal: $0.00"

# List of strings to be outputted / written to file
to_write = [main_heading_string, quantity_string,
            "\n", variable_heading_string, variable_panda_string,
            variable_subtotal_string,
            "\n", fixed_heading_string, fixed_panda_string,
            fixed_subtotal_string, total_expenses_string]

# Print area
print()
for item in to_write:
    print(item)

# create file to hold data (add .txt extension)
file_name = f"{product_name}_{year}_{month}_{day}"
write_to = "{}.txt".format(file_name)

text_file = open(write_to, "w+")

# write the item to file
for item in to_write:
    text_file.write(item)
    text_file.write("\n")