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

namespace ICA15
{
    class Program
    {
        static void Main(string[] args)
        {
            do
            {
                int size = 0;       //user input for size of array
                double[] marks;     //mark array
                string[] strings;   //string array

                //reset console
                Console.Clear();

                //title
                Console.WriteLine("\t\t\tDale Chen-Song Assignment 15\n");

                //get value for size of array
                GetValue("Enter the number of students in the class: ", 4, 10, out size);

                //get array of marks
                marks = MakeRecords(size);

                //get array of strings
                strings = MakeRecords(size, 5, 12);

                //display the contents of the arrays
                Show(marks, strings);

                //display average of the marks
                Average(marks, strings);

                //display those who have failed
                Fails(marks, strings);

                //display message asking user if they want to do it again
                Console.Write("\nRun again? y/n: ");
                //if user inputs yes, loop
            } while (Console.ReadLine().ToLower() == "y");
        }
        //***********************************************************************************
        //Method: static private void GetValue(string prompt, int min, int max, out int input)
        //Purpose: get integer value from user with error and range checking
        //Parameters:   string prompt- prompt to display to the user
        //              int min- the minimum value of range for value
        //              int max- the maximum value of range for value
        //              out int input- input out the valid integer
        //***********************************************************************************
        static private void GetValue(string prompt, int min, int max, out int input)
        {
            bool success = false;   //success flag, true if success

            //repeat until input is right
            do
            {
                //user input value for integer
                Console.Write(prompt);
                success = int.TryParse(Console.ReadLine(), out input);

                //check if the value is valid
                if (!success)
                {
                    //display error message if invalid number, prompt user to try again
                    Console.WriteLine("An invalid number was entered, please try again.");
                }
                //check if the value is within the range
                else if (input < min || input > max)
                {
                    //display error message if out of range, prompt user to try again
                    Console.WriteLine("An out of range number was entered, please try again.");
                }
            }//continue looping until the input is correct
            while (!success || input < min || input > max);
        }
        static private double[] MakeRecords(int input)
        {
            Random generator = new Random();    //random number generator

            //create the array of doubles to the specified size from user
            double[] array = new double[input];

            //randomly generate doubles numbers into the doubles array
            for (int i = 0; i < array.Length; ++i)
            {
                array[i] = (generator.NextDouble() * 100);
            }
            //return the double array to the main program
            return array;
        }
        static private string[] MakeRecords(int input, int min, int max)
        {
            Random generator = new Random();    //random number generator
            string name ="";                    //random string holder

            //create the array of strings to the specified size from user
            string[] array = new string[input];

            //randomly generate strings into the string array
            for (int i = 0; i < array.Length; ++i)
            {
                //reset string for name
                name = "";

                //
                for (int j = 0; j < generator.Next(5, 12); j++)
                {
                    //if it is the first letter, make it a random uppercase
                    if (j == 0)
                    {
                        //generate a random uppercase letter
                        char upperCase = (char)(generator.Next(65, 90));

                        //add that character to the string
                        name += upperCase.ToString();
                    }
                    //otherwise make it a random lowercase letter
                    else
                    {
                        //generate a random lowercase letter
                        char letter = (char)(generator.Next(97, 122));

                        //add that character to the string
                        name += letter.ToString();
                    }
                }
                //have the generated random string in the array
                array[i] = name;
            }
            //return the string array to the main program
            return array;
        }
        //***********************************************************************************
        //Method: static private void Show(double[] arrayMarks, string[] arrayStrings)
        //Purpose: display the contents of both the marks array and strings array
        //Parameters:   double[] arrayMarks- the randomly generated double array to display
        //              string[] arrayStrings- randomly generated string array to display
        //***********************************************************************************
        static private void Show(double[] arrayMarks, string[] arrayStrings)
        {
            //displays the contents of both arrays
            Console.WriteLine($"\n{"Name",15}   {"Mark",-15}");
            Console.WriteLine($"{"----",15}   {"---",-15}");
            for (int i = 0; i < arrayMarks.Length; ++i)
            {
                Console.WriteLine($"{arrayStrings[i], 15:F1} : {arrayMarks[i], -20:F1}");
            }
        }
        //***********************************************************************************
        //Method: static private double Average(int[] array)
        //Purpose: caculate the average of the integers in the array
        //Parameters:   int[] array- randomnly generated integer array
        //Returns:      double average- the calculated average of the array
        //***********************************************************************************
        static private void Average(double[] arrayMarks, string[] arrayStrings)
        {
            double average = 0;     //average of the values in the array
            int total = 0;          //sum of the values in the array

            //sum up the total value within the array
            foreach (int value in arrayMarks)
            {
                total += value;
            }

            //calculating the average of the array
            average = (double)total / arrayMarks.Length;

            //display average of the marks
            Console.WriteLine($"\nThe average of the marks is {average:F1} percent.");


        }
        //***********************************************************************************
        //Method: static private double Average(int[] array)
        //Purpose: caculate the average of the integers in the array
        //Parameters:   int[] array- randomnly generated integer array
        //Returns:      double average- the calculated average of the array
        //***********************************************************************************
        static private void Fails(double[] arrayMarks, string[] arrayStrings)
        {

            //display the list of failing students
            Console.WriteLine("\nHere is a list of failing students...\n");
            Console.WriteLine($"{"Name",15}   {"Mark",-15}");
            Console.WriteLine($"{"----",15}   {"---",-15}");
            for (int i = 0; i < arrayMarks.Length; ++i)
            {
                if (arrayMarks[i] <50.0)
                {
                    Console.WriteLine($"{arrayStrings[i],15:F1} : {arrayMarks[i],-20:F1}");
                }
            }

        }
    }
}