using System;
using System.Collections.Generic;
using UIKit;

namespace GateWay.Ios
{
    public class Application
    {
        // This is the main entry point of the application.
        static void Main(string[] args)
        {
            // if you want to use a different Application Delegate class from "AppDelegate"
            // you can specify it here.
            UIApplication.Main(args, null, "AppDelegate");

            //Study P246
            int x = 40;
            GetAString firstStringMethod = new GetAString(x.ToString);
            GetAString firstStringMethod1 = x.ToString;

            var balance = new Currency(34, 50);
            firstStringMethod1 = balance.ToString;
            firstStringMethod1 = new GetAString(Currency.GetCurrencyUnit);

            #region 简单的委托


            DoubleOp[] operations =
            {
                MathOperation .MultiplyByTwo ,
                MathOperation.Square
            };

            for (int i = 0; i < operations.Length; i++)
            {
                // System.Console.WriteLine($ "Using operations[{i}]:);
                var aa = $"{operations[i]}";
                ProcessAndDisplayNumber(operations[i], 2.0);
                ProcessAndDisplayNumber(operations[i], 7.9);
                ProcessAndDisplayNumber(operations[i], 21.4);
            }

            #region 冒泡排序
            int[] sortArray = { 0, 5, 6, 2, 1 };
            bool swapped = true;
            do
            {
                swapped = false;
                for (int i = 0; i < sortArray.Length - 1; i++)
                {
                    if (sortArray[i] > sortArray[i + 1])
                    {
                        int temp = sortArray[i];
                        sortArray[i] = sortArray[i + 1];
                        sortArray[i - 1] = temp;
                        swapped = true;
                    }
                }
            } while (swapped);


            //第二种方法
            Employee[] employees =
            {
                new Employee ("A",20000),
                new Employee ("B",30000),
                new Employee ("C",40000),
            };

            BubbleSorter.Sort(employees, Employee.CompareSalary);
            foreach (var employee in employees )
            {
                var aa = employee;
            }
            #endregion  
        }



        static void ProcessAndDisplayNumber1(Func<double, double> action, double value)
        {
            double result = action(value);
        }

        //使用Fun<in T,out TResult>来代替自定义的DoubleOp；
        //        <double, double>[] operations1 = 
        //        {
        //            MathOperation.MultiplyByTwo ,
        //            MathOperation.Square
        //};

        static void ProcessAndDisplayNumber(DoubleOp action, double value)
        {
            double result = action(value);
        }

        class MathOperation
        {
            public static double MultiplyByTwo(double value) => value * 2;
            public static double Square(double value) => value * value;
        }

        delegate double DoubleOp(double x);
        #endregion 

        private delegate string GetAString();

        struct Currency
        {
            public uint Dollers;
            public ushort Cents;

            public Currency(uint dollers, ushort cents)
            {
                this.Dollers = dollers;
                this.Cents = cents;
            }

            public override string ToString() => $"${Dollers}.{Cents,2:00}";
            public static string GetCurrencyUnit() => "Dollers";
            public static explicit operator Currency(float value)
            {
                checked
                {
                    uint dollers = (uint)value;
                    ushort cents = (ushort)((value - dollers) + 100);
                    return new Currency(dollers, cents);
                }
            }

            public static implicit operator float(Currency value) =>
            value.Dollers + (value.Cents / 100.0f);

            public static implicit operator Currency(uint value) =>
            new Currency(value, 0);

            public static implicit operator uint(Currency value) =>
            value.Dollers;
        }

        class BubbleSorter
        {
            static public void Sort<T>(IList<T> sortArray, Func<T, T, bool> comparison)
            {
                bool swapped = true;
                do
                {
                    swapped = false;
                    for (int i = 0; i < sortArray.Count - 1;i++){
                        if(comparison (sortArray [i+1],sortArray [i]))
                        {
                            T temp = sortArray[i];
                            sortArray[i] = sortArray[i + 1];
                            sortArray[i + 1] = temp;
                            swapped = true;
                        }
                    }

                } while (swapped);
            }
        }

        class Employee
        {
            public Employee (string name,decimal  salary)
            {
                Name = name;
                Salary = Salary;
            }

            public string Name { get; }
            public Decimal Salary { get; private set; }

            public override string ToString() => $"{Name},{Salary:C}";
            public static bool CompareSalary(Employee e1, Employee e2) => e1.Salary < e2.Salary;
		}

    }
}