using System;

using Bogus;

using System.Linq;

using System.Diagnostics;

using System.Collections.Generic;

using System.Collections.Concurrent;

using System.Threading.Tasks;

​

​

public class Program

{

    public static void Main()

    {

        //Setup Fake Data

        var setting = new Faker<EzEmployee>()

            .RuleFor(p => p.RowId, f => Guid.NewGuid().ToString())

            .RuleFor(p => p.EmailAddress, (f, p) => f.Internet.Email())

            .RuleFor(p => p.Status, f => f.PickRandom<EzStatus>().ToString());

        var emps = setting.Generate(15000);

        Console.WriteLine("Total Distinct Email Count:" + emps.Select(x => x.EmailAddress).Distinct().Count());

        Console.WriteLine(String.Empty);

        /*

            原始資料描述：

                一個 E-Mail 可能有多筆 Record，最終的結果一個 E-Mail 只能有一筆資料

            順序規則：

            - 一個 E-Mail 如果有 ACTIVE 則就使用 ACTIVE 的那筆資料

            - 一個 E-Mail 如果沒有 ACTIVE 則使用比對出 INACTIVE 的那筆資料

            - 一個 E-Mail 如果沒有 ACTIVE 或 INACTIVE 的資料則代表異常則跳過 

            考題：

            - 前提：假資料筆數固定 15000

            - 請參考 GoForeachList 寫出一個新 Function 

                - 最終執行時間要小於 GoForeachList Function

                - 資料筆數要等同於 Total Distinct Email Count And 邏輯要符合上述描述

                - 最終的物件型別為 List<EzEmployee>

        */

        GoForeachList(emps);

    }

    public static void GoForeachList(List<EzEmployee> data)

    {

        var watch = new Stopwatch();

​

        watch.Start();

​

        var goodResult = new List<EzEmployee>();

        goodResult.AddRange(data.Where(x=> x.Status.Equals("ACTIVE", StringComparison.CurrentCultureIgnoreCase))

                            .GroupBy(x=> x.EmailAddress)

                            .Select(g=>g.FirstOrDefault()).ToList());       

        var activeEmailList = goodResult.Select(x => x.EmailAddress).ToList();      

        goodResult.AddRange(data.Where(x => !activeEmailList.Contains(x.EmailAddress) 

                                        && x.Status.Equals("INACTIVE", StringComparison.CurrentCultureIgnoreCase))

                            .GroupBy(x => x.EmailAddress)

                            .Select(g=>g.FirstOrDefault()).ToList());

        /*

        goodResult.AddRange(data.Where(x => !goodResult.Any(a => a.EmailAddress == x.EmailAddress)

                                        && x.Status.Equals("INACTIVE", StringComparison.CurrentCultureIgnoreCase))

                            .GroupBy(x=> x.EmailAddress)

                            .Select(g=>g.FirstOrDefault()).ToList());

        */

        //-----------------------------------------------------------------------//

        /*

        var shootResult = new List<EzEmployee>();

        var emails = data.Select(x => x.EmailAddress).Distinct().ToList();

​

        foreach (var email in emails)

        {

            var activeEntity = data.FirstOrDefault(x => x.EmailAddress == email && x.Status.Equals("ACTIVE", StringComparison.CurrentCultureIgnoreCase));

            if (activeEntity != null)

            {

                shootResult.Add(activeEntity);

            }

            else

            {

                var inActiveEntity = data.FirstOrDefault(x => x.EmailAddress == email && x.Status.Equals("INACTIVE", StringComparison.CurrentCultureIgnoreCase));

                if (inActiveEntity != null)

                {

                    shootResult.Add(inActiveEntity);

                }

            }

        }

        */

​

        watch.Stop();

​

        Console.WriteLine("========= Foreach List =========");

        Console.WriteLine("Exec total Milliseconds:" + watch.ElapsedMilliseconds);

        Console.WriteLine("Exec total count:" + goodResult.Count());

    }

    public enum EzStatus

    {

        ACTIVE,

        INACTIVE

    }

​

    public class EzEmployee

    {

        public int Id { get; set; }

        public string RowId { get; set; }

        public string EmailAddress { get; set; }

        public string Status { get; set; }

    }

}