using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace atm
{
    // =======================================
    // Author: Sam Pourzinal
    // Author ID: n8321744
    // =======================================

    class ATM
    {

        const int SAVING_ACCOUNT = 1;
        const int DEBIT_CARD = 2;
        const int CREDIT_CARD = 3;
        const int LINE_OF_CREDIT = 4;
        static double[] accountBalances = { 0.0, 901.45, 450.0, 1500.0, 2000.0 };
        static string[] accountTypes = { "", "Savings Account", "Debit Card", "Credit Card",
                                       "Line of Credit Account" };

        static void Main(string[] args)
        {
            // Allows the program to continue running through the use of a while loop.
            //Until you clean up the code with Environment.Exit(0) the program will continue running.

            while (true)
            {
                // Prints the main menu selections.
                Console.WriteLine("Welcome to Sam's ATM Simulator \n       Transaction Menu");
                Console.WriteLine("       ================\n       1. Check Balance\n       2. Withdrawal");
                Console.Write("       3. Transfer\n\n\nPlease Enter your choice 1 ... 3 or 0 to exit:  ");
                // Collects the users input and calls the method pertaining to your choice.
                string input = Console.ReadLine();
                //I use else if statements as they allow me to
                       // a) made the codes execution faster by not running unecessary conditionals
                       // b) so I can use one else statement to relate to multiple if statements.
                if (input == "1") CheckBalanceMain();
                else if (input == "2") WithdrawalMain();
                else if (input == "3") TransferMain();
                else if (input == "0") Environment.Exit(0);
                //This else statement is simply some minor error-handling, it does nothing apart from
                //notifying the user that they need to re-enter their input.
                else Console.WriteLine("You pressed an invalid character! Try again.\n\n");

            }
        }

        static void CheckBalanceMain()
        {
            // Prints the account selections.
            Console.WriteLine("\n\n       1. Savings Account\n       2. Debit Card\n       3. Credit Card");
            Console.Write("       4. Line of Credit\n\nPlease Enter your choice 1 ... 4 or 0 to return: ");
            // Collects the users input and converts it to an int, so we can use it to reference an array element.
            string input = Console.ReadLine();
            int whichAccount = Convert.ToInt32(input);
            // Returns the user to the main menu if you input 0.
            if (whichAccount > 0)
                DisplayBalance(whichAccount);
            else Main(new String[0]);
        }

        // Precondition whichAccount
        static void DisplayBalance(int whichAccount)
        {
            // Calls the Date method.
            DateTime date = Date();
            // Prints the balance of the account then returns the user to Main.
            Console.WriteLine("\n\nBalance of {0} is {1}\n",
                              accountTypes[whichAccount], accountBalances[whichAccount]);
            Main(new String[0]);
        }

        static DateTime Date()
        {
            // Prints the current date and time.
            Console.WriteLine();
            DateTime date = DateTime.Now;
            Console.WriteLine("Current Date: {0} ", date);
            return date;
            //As a Post-Condition, we return date, just incase we need to use it later.
            //Post-Condition - Date must be a valid DateTime variable.
        }

        static void WithdrawalMain()
        {
            // Prints the selection of accounts.
            Console.WriteLine("\n\n       1. Savings Account\n       2. Debit Card\n       3. Credit Card");
            Console.Write("       4. Line of Credit\n\nPlease Enter your choice 1 ... 4 or 0 to return:");
            // Reads the users input and converts it to an int.
            string input = Console.ReadLine();
            int whichAccount = Convert.ToInt32(input);
            // If user inputed 0, returns to Main.
            if (whichAccount > 0) WithdrawAmount(whichAccount);
        }

        // Precondition - whichAccount must be a valid integer
        static void WithdrawAmount(int whichAccount)
        {
            // Asks for an amount and converts the input to a double.
            Console.Write("Please enter amount to withdraw: ");
            double amount = Convert.ToDouble(Console.ReadLine());
            // Checks if amount is a a multiple of 10, and is not 10 or 30 (because you can have
            //any odd multiple of 10, but ONLY if it above 30
            if (amount % 10 == 0 & amount != 10 & amount != 30)
            {   //Below ensures that we will have enough money to do the withdraw.
                if ((accountBalances[whichAccount]) - amount < 10)
                {
                    Console.WriteLine("\nThere are insufficient funds in {0}", accountTypes[whichAccount]);
                    WithdrawAmount(whichAccount);
                }
                else
                {
                    if (accountTypes[whichAccount] == "Debit Card" || accountTypes[whichAccount] == "Credit Card")
                        //This applies the 10 cent fee to your account.
                        accountBalances[whichAccount] -= 0.10;
                    accountBalances[whichAccount] -= amount; DispenseCash(amount, whichAccount);
                }
            }
            else
            {
                //Since we're calling this again we dont want the arithmatic to be calculated twice
                Console.WriteLine(" {0} cannot be dispensed.", amount); WithdrawAmount(whichAccount);

            }
        }

        // Precondition - amount must be a valid double, whichAccount must be a valid int
        static void DispenseCash(double amount, int whichAccount)
        {
            // Calculates the number of $50 notes required.
            // We convert it to an int in order to remove its decimal place.
            int numlargenotes = (int)amount / 50;
            //a temporary variable, as we can only declare a variable in an acceptable scope
            int numsmallnotes = 0;
            // Calculates the number of notes in the case that 3 $20 notes are required.
            // i.e. $110 is 1 $50 note, 3 $20 notes.
            if (amount % 50 == 10 || amount % 50 == 30)
            {
                numlargenotes = numlargenotes - 1;
                numsmallnotes = (int)(amount - (50 * numlargenotes)) / 20;
            }
            else
                numsmallnotes = (int)amount % 50 / 20;
            // Prints the amount of notes required for collection.
            Console.WriteLine("\nPlease collect ${0} consisting of:\n{1} $50.00 notes and {2} $20.00 notes."
                            , amount, numlargenotes, numsmallnotes);
            // Calls the Date method to print the date.
            DateTime date = Date();
            // Prints the final balance of the account.
            Console.WriteLine("Balance of {0} is {1}.\n",
                accountTypes[whichAccount], accountBalances[whichAccount]);
        }

        static void TransferMain()
        {
            // Prints the account selection menu and asks which account.
            Console.WriteLine("\n       1. Savings Account\n       2. Debit Card\n       2. Debit Card");
            Console.WriteLine("       3. Credit Card\n       4. Line of Credit\n");
            Console.WriteLine("Transfer from which account?   ");
            Console.Write("Please Enter your choice 1 ... 4 or 0 to return:  ");
            // Converts the users input into an int.
            int fromAccount = Convert.ToInt32(Console.ReadLine());
            // Asks which account to trasnfer to and converts input into int.
            Console.WriteLine("\nTransfer to which account?");
            Console.Write("Please Enter your choice 1 ... 4 or 0 to return:  ");
            int toAccount = Convert.ToInt32(Console.ReadLine());
            // Checks if user has inputed two different accounts.
            if (fromAccount > 0 & toAccount > 0)
                if (fromAccount == toAccount) Console.WriteLine("Must select two different accounts");
                else TransferAmount(fromAccount, toAccount);
        }

        // Precondition - fromAccount must be a valid integer, toAccount must be a valid integer
        static void TransferAmount(int fromAccount, int toAccount)
        {
            // Asks user amount to transfer and converts input to double.
            Console.Write("Please enter amount to Transfer: ");
            string input = Console.ReadLine();
            double amount = Convert.ToDouble(input);
            // Checks if the transfer will leave the account with less than $10.
            if (accountBalances[fromAccount] - accountBalances[toAccount] < 10)
                Console.WriteLine("\nInsufficient Funds to complete transaction\n");
            // If funds available proceeds with the transaction and substitutes 50c.
            else
            {
                accountBalances[fromAccount] = accountBalances[fromAccount] - amount - 0.5;
                accountBalances[toAccount] = accountBalances[toAccount] + amount;
                Console.WriteLine("Transaction was successful.\n");
                // Prints the date and the balance of both accounts.
                DateTime date = Date();
                Console.WriteLine("Balance of {0} is {1}", accountTypes[fromAccount],
                    accountBalances[fromAccount]);
                Console.WriteLine("Balance of {0} is {1}", accountTypes[toAccount],
                    accountBalances[toAccount]);
            }

        }
    }
}