using System.Collections.Generic;
using System.ComponentModel;
using Developpez.Dotnet.ComponentModel;
using NUnit.Framework;

namespace Developpez.Dotnet.Tests.ComponentModel
{
    [TestFixture]
    public class NotifyPropertyChangedExtensionsTests
    {
        #region Test class

        public class Dummy : INotifyPropertyChanged
        {
            public Dummy()
            {
                this.SetDependenciesFor(() => B)
                    .DependsOn(() => A)
                    .Affects(() => C)
                    .Raise(OnPropertyChanged);
            }

            private string _a;
            public string A
            {
                get { return _a; }
                set
                {
                    if (value != _a)
                    {
                        _a = value;
                        OnPropertyChanged("A");
                    }
                }
            }

            public string B
            {
                get { return A + " world"; }
            }

            public string C
            {
                get { return B + " !"; }
            }

            public event PropertyChangedEventHandler PropertyChanged;
            protected virtual void OnPropertyChanged(string propertyName)
            {
                PropertyChanged.Raise(this, propertyName);
            }
        }

        #endregion

        [Test]
        public void Test_DependentPropertiesAreNotified()
        {
            Dummy d = new Dummy();
            List<string> changedProperties = new List<string>();
            d.PropertyChanged += (sender, e) => changedProperties.Add(e.PropertyName);
            d.A = "Hello";
            Assert.IsTrue(changedProperties.Contains("A"));
            Assert.IsTrue(changedProperties.Contains("B"));
            Assert.IsTrue(changedProperties.Contains("C"));
        }

        [Test]
        public void Test_OnPropertyChanged()
        {
            Dummy d = new Dummy();
            List<string> changedProperties = new List<string>();
            PropertyChangedEventHandler handler =
                (sender, e) => changedProperties.Add(e.PropertyName);

            using (d.OnPropertyChanged(() => d.A, handler))
            using (d.OnPropertyChanged(() => d.B, handler))
            using (d.OnPropertyChanged(() => d.C, handler))
            {
                // Vérifie que les handlers sont appelés
                d.A = "Foo";
                Assert.IsTrue(changedProperties.Contains("A"));
                Assert.IsTrue(changedProperties.Contains("B"));
                Assert.IsTrue(changedProperties.Contains("C"));
            }

            // Vérifie que les handlers ne sont plus appelés après
            // la fin du bloc using
            changedProperties.Clear();
            d.A = "Bar";
            Assert.AreEqual(0, changedProperties.Count);
        }
    }
}