using Blacklight.Core.Cameras;
using Blacklight.Core.Keyboard;
using UnitTestSharp;
using Azimuth;
using Annulus;

namespace Glass.Blacklight.UnitTests
{
    public class BlacklightGlassWorldTests : TestFixture
    {
        public class CtorTests : TestFixture
        {
            public void RendersIntoTheScreensExceptionLog()
            {
                var world = new BlacklightGlassWorld();
                CheckEqual(world.screen.Exceptions, world.renderer.Exceptions);
            }
        }

        public class KeyDownTests : TestFixture
        {
            [IgnoreTest]
            private static Control ClickLockedControl(BlacklightGlassWorld world)
            {
                var control = new Control { Bounds = Rect.FromTwoPoints(new Vector(-5, -5), new Vector(5, 5)) };
                control.OnMouseDown += (in MouseState _, MouseButtonFlags __) => { };
                world.screen.Controls.Add(control);
                world.screen.MouseManager.MouseDown(new MouseState { Position = Vector.Zero }, MouseButtonFlags.Left);
                return control;
            }

            public void Escape_WithNothingLocked_ReturnsFalse()
            {
                var world = new BlacklightGlassWorld();

                CheckFalse(world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Escape, default));
            }

            public void Escape_WithAClickLock_CancelsItAndReturnsTrue()
            {
                var world = new BlacklightGlassWorld();
                ClickLockedControl(world);

                CheckTrue(world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Escape, default));
            }

            public void AnyOtherKey_NeverConsumesEvenWithAClickLock()
            {
                var world = new BlacklightGlassWorld();
                ClickLockedControl(world);

                CheckFalse(world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Space, default));
            }

            public void Tab_MovesFocusToTheFirstFocusableControl()
            {
                var world = new BlacklightGlassWorld();
                var control = new Control { Focusable = true };
                world.screen.Controls.Add(control);

                world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Tab, default);

                CheckEqual(control, world.screen.KeyboardManager.Focused);
            }

            public void Tab_ClaimsThePress()
            {
                var world = new BlacklightGlassWorld();
                world.screen.Controls.Add(new Control { Focusable = true });

                CheckTrue(world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Tab, default));
            }

            public void ShiftTab_MovesFocusBackward()
            {
                var world = new BlacklightGlassWorld();
                var first = new Control("first") { Focusable = true };
                var second = new Control("second") { Focusable = true };
                world.screen.Controls.Add(first);
                world.screen.Controls.Add(second);
                world.screen.KeyboardManager.TrySetFocus(second);

                var held = new global::Blacklight.Core.Keyboard.KeyState(
                    global::Blacklight.Core.Keyboard.KeyCode.ShiftLeft);
                world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Tab, held);

                CheckEqual(first, world.screen.KeyboardManager.Focused);
            }

            public void Escape_WithAFocusedControlAndNoClickLock_BlursIt()
            {
                var world = new BlacklightGlassWorld();
                var control = new Control { Focusable = true };
                world.screen.Controls.Add(control);
                world.screen.KeyboardManager.TrySetFocus(control);

                CheckTrue(world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Escape, default));
                CheckNull(world.screen.KeyboardManager.Focused);
            }

            public void Escape_WithBothAClickLockAndAFocusedControl_CancelsTheDragAndLeavesFocusAlone()
            {
                var world = new BlacklightGlassWorld();
                var control = new Control { Focusable = true };
                world.screen.Controls.Add(control);
                world.screen.KeyboardManager.TrySetFocus(control);
                ClickLockedControl(world);

                world.KeyDown(global::Blacklight.Core.Keyboard.KeyCode.Escape, default);

                CheckEqual(control, world.screen.KeyboardManager.Focused);
            }
        }

        public class PointerDownTests : TestFixture
        {
            private static readonly Rect AroundTheOrigin = Rect.FromTwoPoints(new Vector(-5, -5), new Vector(5, 5));

            [IgnoreTest]
            private static BlacklightGlassWorld NewWorld()
            {
                return new BlacklightGlassWorld { camera = new ScreenSpaceCamera { Magnification = 1 } };
            }

            [IgnoreTest]
            private static PointerInput PressAt(Vector position, PointerButtons buttons = PointerButtons.Left)
            {
                return new PointerInput { PixelPos = position, Buttons = buttons };
            }

            public void OnAControlThatTakesFocusOnClick_FocusesIt()
            {
                BlacklightGlassWorld world = NewWorld();
                var control = new Control { Bounds = AroundTheOrigin, Focusable = true, FocusOnClick = true };
                world.screen.Controls.Add(control);

                world.PointerDown(PressAt(Vector.Zero));

                CheckEqual(control, world.screen.KeyboardManager.Focused);
            }

            public void OnAControlThatTakesFocusOnClick_ClaimsThePress()
            {
                BlacklightGlassWorld world = NewWorld();
                world.screen.Controls.Add(
                    new Control { Bounds = AroundTheOrigin, Focusable = true, FocusOnClick = true });

                CheckTrue(world.PointerDown(PressAt(Vector.Zero)));
            }

            public void WithAnyMouseButton_FocusesIt()
            {
                BlacklightGlassWorld world = NewWorld();
                var control = new Control { Bounds = AroundTheOrigin, Focusable = true, FocusOnClick = true };
                world.screen.Controls.Add(control);

                world.PointerDown(PressAt(Vector.Zero, PointerButtons.Right));

                CheckEqual(control, world.screen.KeyboardManager.Focused);
            }

            public void OnAControlThatClaimsThePressWithoutTakingFocus_LeavesFocusAlone()
            {
                BlacklightGlassWorld world = NewWorld();
                var focused = new Control
                {
                    Bounds = Rect.FromTwoPoints(new Vector(50, 50), new Vector(60, 60)),
                    Focusable = true,
                    FocusOnClick = true,
                };
                var button = new Control { Bounds = AroundTheOrigin, Focusable = true };
                button.OnClick += (in MouseState _, MouseButtonFlags __) => { };
                world.screen.Controls.Add(focused);
                world.screen.Controls.Add(button);
                world.screen.KeyboardManager.TrySetFocus(focused);

                world.PointerDown(PressAt(Vector.Zero));

                CheckEqual(focused, world.screen.KeyboardManager.Focused);
            }

            public void OnNothing_ClearsFocus()
            {
                BlacklightGlassWorld world = NewWorld();
                var focused = new Control { Focusable = true };
                world.screen.Controls.Add(focused);
                world.screen.KeyboardManager.TrySetFocus(focused);

                world.PointerDown(PressAt(new Vector(100, 100)));

                CheckNull(world.screen.KeyboardManager.Focused);
            }

            public void OnNothing_DoesNotClaimThePress()
            {
                CheckFalse(NewWorld().PointerDown(PressAt(new Vector(100, 100))));
            }
        }

        public class WheelTests : TestFixture
        {
            private static readonly Rect AroundTheOrigin = Rect.FromTwoPoints(new Vector(-5, -5), new Vector(5, 5));

            [IgnoreTest]
            private static BlacklightGlassWorld NewWorld(Scalar magnification)
            {
                return new BlacklightGlassWorld { camera = new ScreenSpaceCamera { Magnification = magnification } };
            }

            public void OverAControlThatHandlesIt_ReturnsTrue()
            {
                BlacklightGlassWorld world = NewWorld(magnification: 1);
                var control = new Control { Bounds = AroundTheOrigin };
                control.OnMouseWheel += (in MouseState _, Scalar __) => { };
                world.screen.Controls.Add(control);

                CheckTrue(world.Wheel(ticks: 120, Vector.Zero));
            }

            public void NothingHandlingIt_ReturnsFalse()
            {
                BlacklightGlassWorld world = NewWorld(magnification: 1);
                world.screen.Controls.Add(new Control { Bounds = AroundTheOrigin });

                CheckFalse(world.Wheel(ticks: 120, Vector.Zero));
            }

            public void ReportsAHundredAndTwentyTicksAsOneNotch()
            {
                BlacklightGlassWorld world = NewWorld(magnification: 1);
                Scalar? heard = null;
                var control = new Control { Bounds = AroundTheOrigin };
                control.OnMouseWheel += (in MouseState _, Scalar notches) => heard = notches;
                world.screen.Controls.Add(control);

                world.Wheel(ticks: -180, Vector.Zero);

                CheckEqual((Scalar)(-1.5), heard);
            }

            public void ReportsThePositionInGlassSpace()
            {
                BlacklightGlassWorld world = NewWorld(magnification: 2);
                Vector? heardAt = null;
                var control = new Control { Bounds = Rect.FromTwoPoints(Vector.Zero, new Vector(20, 20)) };
                control.OnMouseWheel += (in MouseState state, Scalar _) => heardAt = state.Position;
                world.screen.Controls.Add(control);

                world.Wheel(ticks: 120, new Vector(20, 20));

                CheckEqual(new Vector(10, 10), heardAt);
            }

            public void ReportsNoButtonsHeld()
            {
                BlacklightGlassWorld world = NewWorld(magnification: 1);
                MouseButtonFlags? heard = null;
                var control = new Control { Bounds = AroundTheOrigin };
                control.OnMouseWheel += (in MouseState state, Scalar _) => heard = state.Buttons;
                world.screen.Controls.Add(control);

                world.Wheel(ticks: 120, Vector.Zero);

                CheckEqual(MouseButtonFlags.None, heard);
            }
        }
    }
}