using System;
using System.Collections.Generic;
using System.Collections.Specialized;

using Avalonia.Collections;
using Avalonia.Data.Core;

using Xunit;

namespace Avalonia.Base.UnitTests.Collections
{
    public class AvaloniaDictionaryTests
    {
        [Fact]
        public void Adding_Item_Should_Raise_CollectionChanged()
        {
            var target = new AvaloniaDictionary<string, string>();
            var tracker = new CollectionChangedTracker(target);

            target.Add("foo", "bar");

            Assert.NotNull(tracker.Args);
            Assert.Equal(NotifyCollectionChangedAction.Add, tracker.Args.Action);
            Assert.Equal(-1, tracker.Args.NewStartingIndex);
            Assert.NotNull(tracker.Args.NewItems);
            Assert.Equal(1, tracker.Args.NewItems.Count);
            Assert.Equal(new KeyValuePair<string, string>("foo", "bar"), tracker.Args.NewItems[0]);
        }

        [Fact]
        public void Adding_Item_Should_Raise_PropertyChanged()
        {
            var target = new AvaloniaDictionary<string, string>();
            var tracker = new PropertyChangedTracker(target);

            target.Add("foo", "bar");

            Assert.Equal(new[] { "Count", "Item[foo]" }, tracker.Names);
        }

        [Fact]
        public void Assigning_Item_Should_Raise_CollectionChanged_Add()
        {
            var target = new AvaloniaDictionary<string, string>();
            var tracker = new CollectionChangedTracker(target);

            target["foo"] = "bar";

            Assert.NotNull(tracker.Args);
            Assert.Equal(NotifyCollectionChangedAction.Add, tracker.Args.Action);
            Assert.Equal(-1, tracker.Args.NewStartingIndex);
            Assert.NotNull(tracker.Args.NewItems);
            Assert.Equal(1, tracker.Args.NewItems.Count);
            Assert.Equal(new KeyValuePair<string, string>("foo", "bar"), tracker.Args.NewItems[0]);
        }

        [Fact]
        public void Assigning_Item_Should_Raise_CollectionChanged_Replace()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "baz";
            var tracker = new CollectionChangedTracker(target);
            target["foo"] = "bar";

            Assert.NotNull(tracker.Args);
            Assert.Equal(NotifyCollectionChangedAction.Replace, tracker.Args.Action);
            Assert.Equal(-1, tracker.Args.NewStartingIndex);
            Assert.NotNull(tracker.Args.NewItems);
            Assert.Equal(1, tracker.Args.NewItems.Count);
            Assert.Equal(new KeyValuePair<string, string>("foo", "bar"), tracker.Args.NewItems[0]);
        }

        [Fact]
        public void Assigning_Item_Should_Raise_PropertyChanged_Add()
        {
            var target = new AvaloniaDictionary<string, string>();
            var tracker = new PropertyChangedTracker(target);

            target["foo"] = "bar";

            Assert.Equal(new[] { "Count", "Item[foo]" }, tracker.Names);
        }

        [Fact]
        public void Assigning_Item_Should_Raise_PropertyChanged_Replace()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "baz";
            var tracker = new PropertyChangedTracker(target);
            target["foo"] = "bar";

            Assert.Equal(new[] { "Item[foo]" }, tracker.Names);
        }

        [Fact]
        public void Removing_Item_Should_Raise_CollectionChanged()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "bar";
            var tracker = new CollectionChangedTracker(target);
            target.Remove("foo");

            Assert.NotNull(tracker.Args);
            Assert.Equal(NotifyCollectionChangedAction.Remove, tracker.Args.Action);
            Assert.Equal(-1, tracker.Args.OldStartingIndex);
            Assert.NotNull(tracker.Args.OldItems);
            Assert.Equal(1, tracker.Args.OldItems.Count);
            Assert.Equal(new KeyValuePair<string, string>("foo", "bar"), tracker.Args.OldItems[0]);
        }

        [Fact]
        public void Remove_Method_Should_Remove_Item_From_Collection()
        {
            var target = new AvaloniaDictionary<string, string>() { { "foo", "bar" } };
            Assert.Equal(target.Count, 1);

            target.Remove("foo");
            Assert.Equal(target.Count, 0);
        }

        [Fact]
        public void Removing_Item_Should_Raise_PropertyChanged()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "bar";
            var tracker = new PropertyChangedTracker(target);
            target.Remove("foo");

            Assert.Equal(new[] { "Count", "Item[foo]" }, tracker.Names);
        }

        [Fact]
        public void Clearing_Collection_Should_Raise_CollectionChanged()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "bar";
            target["baz"] = "qux";
            var tracker = new CollectionChangedTracker(target);
            target.Clear();

            Assert.NotNull(tracker.Args);
            Assert.Equal(NotifyCollectionChangedAction.Remove, tracker.Args.Action);
            Assert.Equal(-1, tracker.Args.OldStartingIndex);
            Assert.NotNull(tracker.Args.OldItems);
            Assert.Equal(2, tracker.Args.OldItems.Count);
            Assert.Equal(new KeyValuePair<string, string>("foo", "bar"), tracker.Args.OldItems[0]);
        }

        [Fact]
        public void Clearing_Collection_Should_Raise_PropertyChanged()
        {
            var target = new AvaloniaDictionary<string, string>();

            target["foo"] = "bar";
            target["baz"] = "qux";
            var tracker = new PropertyChangedTracker(target);
            target.Clear();

            Assert.Equal(new[] { "Count", CommonPropertyNames.IndexerName }, tracker.Names);
        }

        [Fact]
        public void Constructor_Should_Throw_ArgumentNullException_When_Collection_Is_Null()
        {
            Assert.Throws<ArgumentNullException>(() =>
            {
                var target = new AvaloniaDictionary<string, string>(null!, null);
            });
        }


        [Fact]
        public void Constructor_Should_Initialize_With_Provided_Collection()
        {
            var initialCollection = new Dictionary<string, string>
            {
                { "key1", "value1" },
                { "key2", "value2" }
            };

            var target = new AvaloniaDictionary<string, string>(initialCollection, null);

            Assert.Equal(2, target.Count);
            Assert.Equal("value1", target["key1"]);
            Assert.Equal("value2", target["key2"]);
        }



    }
}