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

namespace Project
{
    class Program
    {
        struct Student
        {
            public string ID;
            public string Name;
            public string Family;
            public string FatherName;
            public string Gender;
        };
        static void Main(string[] args)
        {

            // Employee emle = new Employee();
            // Professor prfsr = new Professor();
            // Course corse = new Course();
            // Console.WriteLine("Hello World!");

            // corse.GetInfoCourse();
            // Console.WriteLine();


            // corse.ShowInfoCourse();

            const int MAX = 20;
            try
            {
                Student[] stdn = new Student[MAX];
                int itemcount = 0;
                int choice;
                string confirm;
                do
                {
                    displaumenu();
                    System.Console.Write("Enter your Choice: ");
                    choice = int.Parse(Console.ReadLine());
                    Console.Clear();
                    switch (choice)
                    {
                        case 1:
                            add(stdn, ref itemcount);
                            break;
                        case 2:
                            delete(stdn, ref itemcount);
                            break;
                        case 3:
                            update(stdn, itemcount);
                            break;
                        case 4:
                            ViewAll(stdn, itemcount);
                            break;
                        case 5:
                            TopStudent(stdn, itemcount);
                            break;
                        case 6:
                            Find(stdn, itemcount);
                            break;
                        default:
                            System.Console.WriteLine("invalid");
                            break;
                    }
                    Console.WriteLine("Press y or Y to Continue: ");
                    confirm = Console.ReadLine().ToString();
                    Console.Clear();
                } while (confirm == "y" || confirm == "Y");
            }
            catch (FormatException) { Console.WriteLine("invaild input"); }
            Console.ReadLine();
        }
        static void displaumenu()
        {
            Console.WriteLine("=======================================\n");
            Console.WriteLine(" 1. Add Student");
            Console.WriteLine(" 2. Delete Student");
            Console.WriteLine(" 3. Update Student Information");
            Console.WriteLine(" 4. View All Student");
            Console.WriteLine(" 5. Show Top 5 Student");
            Console.WriteLine(" 6. Fint Student by ID");
            Console.WriteLine("****************************************\n");
        }
        static void add(Student[] stdn, ref int itemcount)
        {
        Again:
            Console.WriteLine("===================================\n");
            Console.Write("Enter Student ID: ");
            stdn[itemcount].ID = Console.ReadLine().ToString();
            if (search(stdn, stdn[itemcount].ID, itemcount) != -1)
            {
                Console.Clear();
                Console.WriteLine("ID Vared Shodeh Vojod dareh!");
                goto Again;
            }
            Console.Write("Enter Student Name: ");
            stdn[itemcount].Name = Console.ReadLine().ToString();
            Console.Write("Enter Student Gender (F or M): ");
            stdn[itemcount].Gender = Console.ReadLine().ToString();
            Console.WriteLine("Enter Student Grade: ");
            stdn[itemcount].Name = Console.ReadLine().ToString();
            Console.WriteLine("Enter Student Name: ");
            stdn[itemcount].Name = Console.ReadLine().ToString();
            ++itemcount;
        }
        static void delete(Student[] stdn, ref int itemcount)
        {
            string idd;
            int index;
            if (itemcount > 0)
            {
                Console.WriteLine("=========================\n               Delete Student                \n===========================\n");
                Console.Write("Enter Student ID: ");
                idd = Console.ReadLine();
                index = search(stdn, idd.ToString(), itemcount);

                if ((index != -1) && (itemcount != 0))
                {
                    if (index == (itemcount - 1))
                    {
                        clean(stdn, index);
                        --itemcount;
                        Console.WriteLine("Student Deleted.");
                    }
                    else
                    {
                        for (int i = index; i < itemcount - 1; i++)
                        {
                            stdn[i] = stdn[i + 1];
                            clean(stdn, itemcount);
                            --itemcount;
                        }
                    }
                }
                else Console.WriteLine("In ID Vojood Nadareh. Yek ID ke Az ghabl Vojood Dareh Vared konid.");
            }
            else Console.WriteLine("Hich ID baraye Delete Vojod Nadareh!");
        }

        static void update(Student[] stdn, ref int itemcount)
        {
            string idd;
            int column_index;
            Console.WriteLine("===================\n               Update Student Information              \n========================\n");
            Console.WriteLine("Enter Student ID: ");
            idd = Console.ReadLine();
            Console.WriteLine("Kodam field Ro Mikhaiid Update Konid (1-6)? ");
            Console.WriteLine("1. Student Name");
            Console.WriteLine("2. Student Family");
            Console.WriteLine("3. Student Father Name");
            Console.WriteLine("4. Student Code Meli");
            Console.WriteLine("5. Student Gender");
            Console.WriteLine("===================\n");
            column_index = int.Parse(Console.ReadLine());
            int index = search(stdn, idd.ToString(), itemcount);
            if ((index != -1) && (itemcount != 0))
            {
                if (column_index == 1)
                {
                    Console.WriteLine("Enter Student Name: ");
                    stdn[index].Name = Console.ReadLine().ToString();
                }
                else if (column_index == 2)
                {
                    Console.WriteLine("Enter Student Family: ");
                    stdn[index].Family = Console.ReadLine().ToString();
                }
                else if (column_index == 3)
                {
                    Console.WriteLine("Enter Student Father Name: ");
                    stdn[index].FatherName = Console.ReadLine().ToString();
                }
                else Console.WriteLine("invalid column index");
            }
            else Console.WriteLine("In ID Vojood Nadareh. Yek ID ke Az ghabl Vojood Dareh Vared konid.");

        }
        static void ViewAll(Student[] stdn, ref int itemcount)
        {
            int i = 0;
            Console.WriteLine("================\n         View All Student             \n===================\n");
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine();
            while (i < itemcount)
            {
                if (stdn[i].Name != null)
                {
                    Console.Write(stdn[i].ID, stdn[i].Name, stdn[i].Gender);
                    Console.Write("\n----------------------------\n");
                }
                i = i + 1;
            }
        }
        static void TopStudent(Student[] stdn, ref int itemcount)
        {

        }
        static void Find(Student[] stdn, int itemcount)
        {
            Console.WriteLine("===============\n           Find Student by ID           \n================\n");
            string idd;
            Console.Write("Enter Student ID: ");
            idd = Console.ReadLine();
            int index = search(stdn, idd.ToString(), itemcount);
            if (index != -1)
            {
                Console.Write(stdn[index].ID, stdn[index].Name, stdn[index].Gender);
                Console.WriteLine();
            }
            else Console.WriteLine("in field Vojood Nadareh!");
        }
        static int search(Student[] stdn, string idd, ref int itemcount)
        {
            int found = -1;
            for (int i = 0; i < itemcount && found == -1; i++)
            {
                if (stdn[i].ID == idd) found = i;

                else found = -1;
            }
            return found;
        }
        static void clean(Student[] stdn, int index)
        {
            stdn[index].ID = null;
            stdn[index].Name = null;
            stdn[index].Family = null;
            stdn[index].FatherName = null;
        }
    }
}