gui-cs.Terminal.Gui/UnitTests/View/Navigation/HasFocusChangeEventTests.cs

using Xunit.Abstractions;

namespace Terminal.Gui.ViewTests;

public class HasFocusChangeEventTests (ITestOutputHelper _output) : TestsAllViews
{
    [Fact]
    public void HasFocusChanging_SetFocus_Raises ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        Assert.True (view.CanFocus);
        Assert.False (view.HasFocus);

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);
    }


    [Fact]
    public void HasFocusChanging_SetFocus_SubView_SetFocus_Raises ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         subviewHasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         subviewHasFocusFalseCount++;
                                     }
                                 };

        view.Add (subview);

        view.SetFocus ();

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }


    [Fact]
    public void HasFocusChanging_SetFocus_On_SubView_SubView_SetFocus_Raises ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subviewHasFocusTrueCount++;
                                        }
                                        else
                                        {
                                            subviewHasFocusFalseCount++;
                                        }
                                    };

        view.Add (subview);

        subview.SetFocus ();

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }

    [Fact]
    public void HasFocusChanging_SetFocus_CompoundSubView_Raises ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subViewEnterCount = 0;
        var subViewLeaveCount = 0;

        var subView = new View
        {
            Id = "subView",
            CanFocus = true
        };
        subView.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subViewEnterCount++;
                                        }
                                        else
                                        {
                                            subViewLeaveCount++;
                                        }
                                    };

        var subviewSubView1EnterCount = 0;
        var subviewSubView1LeaveCount = 0;

        var subViewSubView1 = new View
        {
            Id = "subViewSubView1",
            CanFocus = false
        };
        subViewSubView1.HasFocusChanging += (s, e) =>
                                            {
                                                if (e.NewValue)
                                                {
                                                    subviewSubView1EnterCount++;
                                                }
                                                else
                                                {
                                                    subviewSubView1LeaveCount++;
                                                }
                                            };

        var subviewSubView2EnterCount = 0;
        var subviewSubView2LeaveCount = 0;

        var subViewSubView2 = new View
        {
            Id = "subViewSubView2",
            CanFocus = true
        };
        subViewSubView2.HasFocusChanging += (s, e) =>
                                            {
                                                if (e.NewValue)
                                                {
                                                    subviewSubView2EnterCount++;
                                                }
                                                else
                                                {
                                                    subviewSubView2EnterCount++;
                                                }
                                            };

        var subviewSubView3EnterCount = 0;
        var subviewSubView3LeaveCount = 0;

        var subViewSubView3 = new View
        {
            Id = "subViewSubView3",
            CanFocus = false
        };
        subViewSubView3.HasFocusChanging += (s, e) =>
                                            {
                                                if (e.NewValue)
                                                {
                                                    subviewSubView3EnterCount++;
                                                }
                                                else
                                                {
                                                    subviewSubView3LeaveCount++;
                                                }
                                            };

        subView.Add (subViewSubView1, subViewSubView2, subViewSubView3);

        view.Add (subView);

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.True (subView.HasFocus);
        Assert.False (subViewSubView1.HasFocus);
        Assert.True (subViewSubView2.HasFocus);
        Assert.False (subViewSubView3.HasFocus);

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subViewEnterCount);
        Assert.Equal (0, subViewLeaveCount);

        Assert.Equal (0, subviewSubView1EnterCount);
        Assert.Equal (0, subviewSubView1LeaveCount);

        Assert.Equal (1, subviewSubView2EnterCount);
        Assert.Equal (0, subviewSubView2LeaveCount);

        Assert.Equal (0, subviewSubView3EnterCount);
        Assert.Equal (0, subviewSubView3LeaveCount);
    }

    [Fact]
    public void HasFocusChanging_Can_Cancel ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                         e.Cancel = true;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subviewHasFocusTrueCount++;
                                        }
                                        else
                                        {
                                            subviewHasFocusFalseCount++;
                                        }
                                    };

        view.Add (subview);

        view.SetFocus ();

        Assert.False (view.HasFocus);
        Assert.False (subview.HasFocus);

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (0, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }

    [Fact]
    public void HasFocusChanging_SetFocus_On_SubView_Can_Cancel ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                         e.Cancel = true;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subviewHasFocusTrueCount++;
                                        }
                                        else
                                        {
                                            subviewHasFocusFalseCount++;
                                        }
                                    };

        view.Add (subview);

        subview.SetFocus ();

        Assert.False (view.HasFocus);
        Assert.False (subview.HasFocus);

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }

    [Fact]
    public void HasFocusChanging_SubView_Can_Cancel ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subviewHasFocusTrueCount++;
                                            e.Cancel = true;
                                        }
                                        else
                                        {
                                            subviewHasFocusFalseCount++;
                                        }
                                    };

        view.Add (subview);

        view.SetFocus ();

        Assert.True (view.HasFocus);
        Assert.False (subview.HasFocus);

        Assert.Equal (1, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }


    [Fact]
    public void HasFocusChanging_SetFocus_On_Subview_SubView_Can_Cancel ()
    {
        var hasFocusTrueCount = 0;
        var hasFocusFalseCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) =>
                                 {
                                     if (e.NewValue)
                                     {
                                         hasFocusTrueCount++;
                                     }
                                     else
                                     {
                                         hasFocusFalseCount++;
                                     }
                                 };

        var subviewHasFocusTrueCount = 0;
        var subviewHasFocusFalseCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) =>
                                    {
                                        if (e.NewValue)
                                        {
                                            subviewHasFocusTrueCount++;
                                            e.Cancel = true;
                                        }
                                        else
                                        {
                                            subviewHasFocusFalseCount++;
                                        }
                                    };

        view.Add (subview);

        subview.SetFocus ();

        Assert.False (view.HasFocus);
        Assert.False (subview.HasFocus);

        Assert.Equal (0, hasFocusTrueCount);
        Assert.Equal (0, hasFocusFalseCount);

        Assert.Equal (1, subviewHasFocusTrueCount);
        Assert.Equal (0, subviewHasFocusFalseCount);
    }

    [Fact]
    public void RemoveFocus_Raises_HasFocusChanged ()
    {
        var nEnter = 0;
        var nLeave = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) => nEnter++;
        view.HasFocusChanged += (s, e) => nLeave++;

        Assert.True (view.CanFocus);
        Assert.False (view.HasFocus);

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.Equal (1, nEnter);
        Assert.Equal (0, nLeave);

        view.HasFocus = false;
        Assert.Equal (1, nEnter);
        Assert.Equal (1, nLeave);
    }


    [Fact]
    public void RemoveFocus_SubView_Raises_HasFocusChanged ()
    {
        var viewEnterCount = 0;
        var viewLeaveCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) => viewEnterCount++;
        view.HasFocusChanged += (s, e) => viewLeaveCount++;

        var subviewEnterCount = 0;
        var subviewLeaveCount = 0;

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        subview.HasFocusChanging += (s, e) => subviewEnterCount++;
        subview.HasFocusChanged += (s, e) => subviewLeaveCount++;

        view.Add (subview);

        view.SetFocus ();

        view.HasFocus = false;

        Assert.Equal (1, viewEnterCount);
        Assert.Equal (1, viewLeaveCount);

        Assert.Equal (1, subviewEnterCount);
        Assert.Equal (1, subviewLeaveCount);

        view.SetFocus ();

        Assert.Equal (2, viewEnterCount);
        Assert.Equal (1, viewLeaveCount);

        Assert.Equal (2, subviewEnterCount);
        Assert.Equal (1, subviewLeaveCount);

        subview.HasFocus = false;

        Assert.Equal (2, viewEnterCount);
        Assert.Equal (2, viewLeaveCount);

        Assert.Equal (2, subviewEnterCount);
        Assert.Equal (2, subviewLeaveCount);
    }

    [Fact]
    public void RemoveFocus_CompoundSubView_Raises_HasFocusChanged ()
    {
        var viewEnterCount = 0;
        var viewLeaveCount = 0;

        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        view.HasFocusChanging += (s, e) => viewEnterCount++;
        view.HasFocusChanged += (s, e) => viewLeaveCount++;

        var subViewEnterCount = 0;
        var subViewLeaveCount = 0;

        var subView = new View
        {
            Id = "subView",
            CanFocus = true
        };
        subView.HasFocusChanging += (s, e) => subViewEnterCount++;
        subView.HasFocusChanged += (s, e) => subViewLeaveCount++;

        var subviewSubView1EnterCount = 0;
        var subviewSubView1LeaveCount = 0;

        var subViewSubView1 = new View
        {
            Id = "subViewSubView1",
            CanFocus = false
        };
        subViewSubView1.HasFocusChanging += (s, e) => subviewSubView1EnterCount++;
        subViewSubView1.HasFocusChanged += (s, e) => subviewSubView1LeaveCount++;

        var subviewSubView2EnterCount = 0;
        var subviewSubView2LeaveCount = 0;

        var subViewSubView2 = new View
        {
            Id = "subViewSubView2",
            CanFocus = true
        };
        subViewSubView2.HasFocusChanging += (s, e) => subviewSubView2EnterCount++;
        subViewSubView2.HasFocusChanged += (s, e) => subviewSubView2LeaveCount++;

        var subviewSubView3EnterCount = 0;
        var subviewSubView3LeaveCount = 0;

        var subViewSubView3 = new View
        {
            Id = "subViewSubView3",
            CanFocus = false
        };
        subViewSubView3.HasFocusChanging += (s, e) => subviewSubView3EnterCount++;
        subViewSubView3.HasFocusChanged += (s, e) => subviewSubView3LeaveCount++;

        subView.Add (subViewSubView1, subViewSubView2, subViewSubView3);

        view.Add (subView);

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.True (subView.HasFocus);
        Assert.False (subViewSubView1.HasFocus);
        Assert.True (subViewSubView2.HasFocus);
        Assert.False (subViewSubView3.HasFocus);

        view.HasFocus = false;
        Assert.False (view.HasFocus);
        Assert.False (subView.HasFocus);
        Assert.False (subViewSubView1.HasFocus);
        Assert.False (subViewSubView2.HasFocus);
        Assert.False (subViewSubView3.HasFocus);

        Assert.Equal (1, viewEnterCount);
        Assert.Equal (1, viewLeaveCount);

        Assert.Equal (1, subViewEnterCount);
        Assert.Equal (1, subViewLeaveCount);

        Assert.Equal (0, subviewSubView1EnterCount);
        Assert.Equal (0, subviewSubView1LeaveCount);

        Assert.Equal (1, subviewSubView2EnterCount);
        Assert.Equal (1, subviewSubView2LeaveCount);

        Assert.Equal (0, subviewSubView3EnterCount);
        Assert.Equal (0, subviewSubView3LeaveCount);
    }

    [Fact]
    public void HasFocus_False_Leave_Raised ()
    {
        var view = new View
        {
            Id = "view",
            CanFocus = true
        };
        Assert.True (view.CanFocus);
        Assert.False (view.HasFocus);

        var leaveInvoked = 0;

        view.HasFocusChanged += (s, e) => leaveInvoked++;

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.Equal (0, leaveInvoked);

        view.HasFocus = false;
        Assert.False (view.HasFocus);
        Assert.Equal (1, leaveInvoked);
    }

    [Fact]
    public void HasFocus_False_Leave_Raised_ForAllSubViews ()
    {
        var view = new View
        {
            Id = "view",
            CanFocus = true
        };

        var subview = new View
        {
            Id = "subview",
            CanFocus = true
        };
        view.Add (subview);

        var leaveInvoked = 0;

        view.HasFocusChanged += (s, e) => leaveInvoked++;
        subview.HasFocusChanged += (s, e) => leaveInvoked++;

        view.SetFocus ();
        Assert.True (view.HasFocus);
        Assert.Equal (0, leaveInvoked);

        view.HasFocus = false;
        Assert.False (view.HasFocus);
        Assert.False (subview.HasFocus);
        Assert.Equal (2, leaveInvoked);
    }
}