// Copyright (c) The Avalonia Project. All rights reserved.
// Licensed under the MIT license. See licence.md file in the project root for full license information.

using System;
using System.Reactive.Linq;
using Avalonia.Controls.Presenters;
using Avalonia.Controls.Primitives;
using Avalonia.Controls.Templates;
using Avalonia.Data;
using Avalonia.Input;
using Avalonia.Media;
using Avalonia.Platform;
using Avalonia.UnitTests;
using Moq;
using Xunit;

namespace Avalonia.Controls.UnitTests
{
    public class TextBoxTests
    {
        [Fact]
        public void DefaultBindingMode_Should_Be_TwoWay()
        {
            Assert.Equal(
                BindingMode.TwoWay,
                TextBox.TextProperty.GetMetadata(typeof(TextBox)).DefaultBindingMode);
        }

        [Fact]
        public void CaretIndex_Can_Moved_To_Position_After_The_End_Of_Text_With_Arrow_Key()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "1234"
                };

                target.CaretIndex = 3;
                RaiseKeyEvent(target, Key.Right, 0);

                Assert.Equal(4, target.CaretIndex);
            }
        }

        [Fact]
        public void Press_Ctrl_A_Select_All_Text()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "1234"
                };

                RaiseKeyEvent(target, Key.A, KeyModifiers.Control);

                Assert.Equal(0, target.SelectionStart);
                Assert.Equal(4, target.SelectionEnd);
            }
        }

        [Fact]
        public void Press_Ctrl_A_Select_All_Null_Text()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate()
                };

                RaiseKeyEvent(target, Key.A, KeyModifiers.Control);

                Assert.Equal(0, target.SelectionStart);
                Assert.Equal(0, target.SelectionEnd);
            }
        }

        [Fact]
        public void Press_Ctrl_Z_Will_Not_Modify_Text()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "1234"
                };

                RaiseKeyEvent(target, Key.Z, KeyModifiers.Control);

                Assert.Equal("1234", target.Text);
            }
        }

        [Fact]
        public void Typing_Beginning_With_0_Should_Not_Modify_Text_When_Bound_To_Int()
        {
            using (UnitTestApplication.Start(Services))
            {
                var source = new Class1();
                var target = new TextBox
                {
                    DataContext = source,
                    Template = CreateTemplate(),
                };

                target.ApplyTemplate();
                target.Bind(TextBox.TextProperty, new Binding(nameof(Class1.Foo), BindingMode.TwoWay));

                Assert.Equal("0", target.Text);

                target.CaretIndex = 1;
                target.RaiseEvent(new TextInputEventArgs
                {
                    RoutedEvent = InputElement.TextInputEvent,
                    Text = "2",
                });

                Assert.Equal("02", target.Text);
            }
        }

        [Fact]
        public void Control_Backspace_Should_Remove_The_Word_Before_The_Caret_If_There_Is_No_Selection()
        {
            using (UnitTestApplication.Start(Services))
            {
                TextBox textBox = new TextBox
                {
                    Text = "First Second Third Fourth",
                    CaretIndex = 5
                };

                // (First| Second Third Fourth)
                RaiseKeyEvent(textBox, Key.Back, KeyModifiers.Control);
                Assert.Equal(" Second Third Fourth", textBox.Text);

                // ( Second |Third Fourth)
                textBox.CaretIndex = 8;
                RaiseKeyEvent(textBox, Key.Back, KeyModifiers.Control);
                Assert.Equal(" Third Fourth", textBox.Text);

                // ( Thi|rd Fourth)
                textBox.CaretIndex = 4;
                RaiseKeyEvent(textBox, Key.Back, KeyModifiers.Control);
                Assert.Equal(" rd Fourth", textBox.Text);

                // ( rd F[ou]rth)
                textBox.SelectionStart = 5;
                textBox.SelectionEnd = 7;

                RaiseKeyEvent(textBox, Key.Back, KeyModifiers.Control);
                Assert.Equal(" rd Frth", textBox.Text);

                // ( |rd Frth)
                textBox.CaretIndex = 1;
                RaiseKeyEvent(textBox, Key.Back, KeyModifiers.Control);
                Assert.Equal("rd Frth", textBox.Text);
            }
        }

        [Fact]
        public void Control_Delete_Should_Remove_The_Word_After_The_Caret_If_There_Is_No_Selection()
        {
            using (UnitTestApplication.Start(Services))
            {
                TextBox textBox = new TextBox
                {
                    Text = "First Second Third Fourth",
                    CaretIndex = 19
                };

                // (First Second Third |Fourth)
                RaiseKeyEvent(textBox, Key.Delete, KeyModifiers.Control);
                Assert.Equal("First Second Third ", textBox.Text);

                // (First Second |Third )
                textBox.CaretIndex = 13;
                RaiseKeyEvent(textBox, Key.Delete, KeyModifiers.Control);
                Assert.Equal("First Second ", textBox.Text);

                // (First Sec|ond )
                textBox.CaretIndex = 9;
                RaiseKeyEvent(textBox, Key.Delete, KeyModifiers.Control);
                Assert.Equal("First Sec", textBox.Text);

                // (Fi[rs]t Sec )
                textBox.SelectionStart = 2;
                textBox.SelectionEnd = 4;

                RaiseKeyEvent(textBox, Key.Delete, KeyModifiers.Control);
                Assert.Equal("Fit Sec", textBox.Text);

                // (Fit Sec| )
                textBox.Text += " ";
                textBox.CaretIndex = 7;
                RaiseKeyEvent(textBox, Key.Delete, KeyModifiers.Control);
                Assert.Equal("Fit Sec", textBox.Text);
            }
        }

        [Fact]
        public void Setting_SelectionStart_To_SelectionEnd_Sets_CaretPosition_To_SelectionStart()
        {
            using (UnitTestApplication.Start(Services))
            {
                var textBox = new TextBox
                {
                    Text = "0123456789"
                };

                textBox.SelectionStart = 2;
                textBox.SelectionEnd = 2;
                Assert.Equal(2, textBox.CaretIndex);
            }
        }

        [Fact]
        public void Setting_Text_Updates_CaretPosition()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Text = "Initial Text",
                    CaretIndex = 11
                };

                var invoked = false;

                target.GetObservable(TextBox.TextProperty).Skip(1).Subscribe(_ =>
                {
                    // Caret index should be set before Text changed notification, as we don't want
                    // to notify with an invalid CaretIndex.
                    Assert.Equal(7, target.CaretIndex);
                    invoked = true;
                });

                target.Text = "Changed";

                Assert.True(invoked);
            }
        }

        [Fact]
        public void Press_Enter_Does_Not_Accept_Return()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    AcceptsReturn = false,
                    Text = "1234"
                };

                RaiseKeyEvent(target, Key.Enter, 0);

                Assert.Equal("1234", target.Text);
            }
        }

        [Fact]
        public void Press_Enter_Add_Default_Newline()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    AcceptsReturn = true
                };

                RaiseKeyEvent(target, Key.Enter, 0);

                Assert.Equal(Environment.NewLine, target.Text);
            }
        }

        [Fact]
        public void Press_Enter_Add_Custom_Newline()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    AcceptsReturn = true,
                    NewLine = "Test"
                };

                RaiseKeyEvent(target, Key.Enter, 0);

                Assert.Equal("Test", target.Text);
            }
        }

        [Theory]
        [InlineData(new object[] { false, TextWrapping.NoWrap, ScrollBarVisibility.Hidden })]
        [InlineData(new object[] { false, TextWrapping.Wrap, ScrollBarVisibility.Hidden })]
        [InlineData(new object[] { true, TextWrapping.NoWrap, ScrollBarVisibility.Auto })]
        [InlineData(new object[] { true, TextWrapping.Wrap, ScrollBarVisibility.Disabled })]
        public void Has_Correct_Horizontal_ScrollBar_Visibility(
            bool acceptsReturn,
            TextWrapping wrapping,
            ScrollBarVisibility expected)
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    AcceptsReturn = acceptsReturn,
                    TextWrapping = wrapping,
                };

                Assert.Equal(expected, ScrollViewer.GetHorizontalScrollBarVisibility(target));
            }
        }

        [Fact]
        public void SelectionEnd_Doesnt_Cause_Exception()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "0123456789"
                };

                target.SelectionStart = 0;
                target.SelectionEnd = 9;

                target.Text = "123";

                RaiseTextEvent(target, "456");

                Assert.True(true);
            }
        }

        [Fact]
        public void SelectionStart_Doesnt_Cause_Exception()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "0123456789"
                };

                target.SelectionStart = 8;
                target.SelectionEnd = 9;

                target.Text = "123";

                RaiseTextEvent(target, "456");

                Assert.True(true);
            }
        }

        [Fact]
        public void SelectionStartEnd_Are_Valid_AterTextChange()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "0123456789"
                };

                target.SelectionStart = 8;
                target.SelectionEnd = 9;

                target.Text = "123";

                Assert.True(target.SelectionStart <= "123".Length);
                Assert.True(target.SelectionEnd <= "123".Length);
            }
        }
        [Fact]
        public void CoerceCaretIndex_Doesnt_Cause_Exception_with_malformed_line_ending()
        {
            using (UnitTestApplication.Start(Services))
            {
                var target = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "0123456789\r"
                };
                target.CaretIndex = 11;

                Assert.True(true);
            }
        }

        [Fact]
        public void TextBox_GotFocus_And_LostFocus_Work_Properly()
        {
            using (UnitTestApplication.Start(FocusServices))
            {
                var target1 = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "1234"
                };
                var target2 = new TextBox
                {
                    Template = CreateTemplate(),
                    Text = "5678"
                };
                var sp = new StackPanel();
                sp.Children.Add(target1);
                sp.Children.Add(target2);

                target1.ApplyTemplate();
                target2.ApplyTemplate();
                
                var root = new TestRoot { Child = sp };

                var gfcount = 0;
                var lfcount = 0;

                target1.GotFocus += (s, e) => gfcount++;
                target2.LostFocus += (s, e) => lfcount++;

                target2.Focus();
                Assert.False(target1.IsFocused);
                Assert.True(target2.IsFocused);

                target1.Focus();
                Assert.False(target2.IsFocused);
                Assert.True(target1.IsFocused);

                Assert.Equal(1, gfcount);
                Assert.Equal(1, lfcount);
            }
        }

        [Fact]
        public void Setting_Bound_Text_To_Null_Works()
        {
            using (UnitTestApplication.Start(Services))
            {
                var source = new Class1 { Bar = "bar" };
                var target = new TextBox { DataContext = source };

                target.Bind(TextBox.TextProperty, new Binding("Bar"));

                Assert.Equal("bar", target.Text);
                source.Bar = null;
                Assert.Null(target.Text);
            }
        }

        private static TestServices FocusServices => TestServices.MockThreadingInterface.With(
            focusManager: new FocusManager(),
            keyboardDevice: () => new KeyboardDevice(),
            keyboardNavigation: new KeyboardNavigationHandler(),
            inputManager: new InputManager(),
            standardCursorFactory: Mock.Of<IStandardCursorFactory>());

        private static TestServices Services => TestServices.MockThreadingInterface.With(
            standardCursorFactory: Mock.Of<IStandardCursorFactory>());

        private IControlTemplate CreateTemplate()
        {
            return new FuncControlTemplate<TextBox>((control, scope) =>
                new TextPresenter
                {
                    Name = "PART_TextPresenter",
                    [!!TextPresenter.TextProperty] = new Binding
                    {
                        Path = "Text",
                        Mode = BindingMode.TwoWay,
                        Priority = BindingPriority.TemplatedParent,
                        RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent),
                    },
                }.RegisterInNameScope(scope));
        }

        private void RaiseKeyEvent(TextBox textBox, Key key, KeyModifiers inputModifiers)
        {
            textBox.RaiseEvent(new KeyEventArgs
            {
                RoutedEvent = InputElement.KeyDownEvent,
                KeyModifiers = inputModifiers,
                Key = key
            });
        }

        private void RaiseTextEvent(TextBox textBox, string text)
        {
            textBox.RaiseEvent(new TextInputEventArgs
            {
                RoutedEvent = InputElement.TextInputEvent,
                Text = text
            });
        }

        private class Class1 : NotifyingBase
        {
            private int _foo;
            private string _bar;

            public int Foo
            {
                get { return _foo; }
                set { _foo = value; RaisePropertyChanged(); }
            }

            public string Bar
            {
                get { return _bar; }
                set { _bar = value; RaisePropertyChanged(); }
            }
        }
    }
}