// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

#nullable disable

using System;
using System.Linq;
using JetBrains.Annotations;
using NUnit.Framework;
using osu.Framework.Allocation;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Primitives;
using osu.Framework.Testing;
using osu.Framework.Threading;
using osu.Game.Screens.Edit.Compose.Components;
using osu.Game.Utils;
using osuTK;
using osuTK.Input;

namespace osu.Game.Tests.Visual.Editing
{
    public partial class TestSceneComposeSelectBox : OsuManualInputManagerTestScene
    {
        private Container selectionArea;
        private SelectionBox selectionBox;

        [Cached(typeof(SelectionRotationHandler))]
        private TestSelectionRotationHandler rotationHandler;

        [Cached(typeof(SelectionScaleHandler))]
        private TestSelectionScaleHandler scaleHandler;

        public TestSceneComposeSelectBox()
        {
            rotationHandler = new TestSelectionRotationHandler(() => selectionArea);
            scaleHandler = new TestSelectionScaleHandler(() => selectionArea);
        }

        [SetUp]
        public void SetUp() => Schedule(() =>
        {
            Child = selectionArea = new Container
            {
                Size = new Vector2(400),
                Position = -new Vector2(150),
                Anchor = Anchor.Centre,
                Children = new Drawable[]
                {
                    selectionBox = new SelectionBox
                    {
                        RelativeSizeAxes = Axes.Both,

                        CanFlipX = true,
                        CanFlipY = true,
                    }
                }
            };

            InputManager.MoveMouseTo(selectionBox);
            InputManager.ReleaseButton(MouseButton.Left);
        });

        private partial class TestSelectionRotationHandler : SelectionRotationHandler
        {
            private readonly Func<Container> getTargetContainer;

            public TestSelectionRotationHandler(Func<Container> getTargetContainer)
            {
                this.getTargetContainer = getTargetContainer;

                CanRotate.Value = true;
            }

            [CanBeNull]
            private Container targetContainer;

            private float? initialRotation;

            public override void Begin()
            {
                if (targetContainer != null)
                    throw new InvalidOperationException($"Cannot {nameof(Begin)} a rotate operation while another is in progress!");

                targetContainer = getTargetContainer();
                initialRotation = targetContainer!.Rotation;
            }

            public override void Update(float rotation, Vector2? origin = null)
            {
                if (targetContainer == null)
                    throw new InvalidOperationException($"Cannot {nameof(Update)} a rotate operation without calling {nameof(Begin)} first!");

                // kinda silly and wrong, but just showing that the drag handles work.
                targetContainer.Rotation = initialRotation!.Value + rotation;
            }

            public override void Commit()
            {
                if (targetContainer == null)
                    throw new InvalidOperationException($"Cannot {nameof(Commit)} a rotate operation without calling {nameof(Begin)} first!");

                targetContainer = null;
                initialRotation = null;
            }
        }

        private partial class TestSelectionScaleHandler : SelectionScaleHandler
        {
            private readonly Func<Container> getTargetContainer;

            public TestSelectionScaleHandler(Func<Container> getTargetContainer)
            {
                this.getTargetContainer = getTargetContainer;

                CanScaleX.Value = true;
                CanScaleY.Value = true;
                CanScaleDiagonally.Value = true;
            }

            [CanBeNull]
            private Container targetContainer;

            public override void Begin()
            {
                if (targetContainer != null)
                    throw new InvalidOperationException($"Cannot {nameof(Begin)} a scale operation while another is in progress!");

                targetContainer = getTargetContainer();
                OriginalSurroundingQuad = new Quad(targetContainer!.X, targetContainer.Y, targetContainer.Width, targetContainer.Height);
            }

            public override void Update(Vector2 scale, Vector2? origin = null)
            {
                if (targetContainer == null)
                    throw new InvalidOperationException($"Cannot {nameof(Update)} a scale operation without calling {nameof(Begin)} first!");

                Vector2 actualOrigin = origin ?? Vector2.Zero;

                targetContainer.Position = GeometryUtils.GetScaledPosition(scale, actualOrigin, OriginalSurroundingQuad!.Value.TopLeft);
                targetContainer.Size = OriginalSurroundingQuad!.Value.Size * scale;
            }

            public override void Commit()
            {
                if (targetContainer == null)
                    throw new InvalidOperationException($"Cannot {nameof(Commit)} a scale operation without calling {nameof(Begin)} first!");

                targetContainer = null;
            }
        }

        [Test]
        public void TestRotationHandleShownOnHover()
        {
            SelectionBoxRotationHandle rotationHandle = null;

            AddStep("retrieve rotation handle", () => rotationHandle = this.ChildrenOfType<SelectionBoxRotationHandle>().First());

            AddAssert("handle hidden", () => rotationHandle.Alpha == 0);
            AddStep("hover over handle", () => InputManager.MoveMouseTo(rotationHandle));
            AddUntilStep("rotation handle shown", () => rotationHandle.Alpha == 1);

            AddStep("move mouse away", () => InputManager.MoveMouseTo(selectionBox));
            AddUntilStep("handle hidden", () => rotationHandle.Alpha == 0);
        }

        [Test]
        public void TestRotationHandleShownOnHoveringClosestScaleHandler()
        {
            SelectionBoxRotationHandle rotationHandle = null;

            AddStep("retrieve rotation handle", () => rotationHandle = this.ChildrenOfType<SelectionBoxRotationHandle>().First());

            AddAssert("rotation handle hidden", () => rotationHandle.Alpha == 0);
            AddStep("hover over closest scale handle", () =>
            {
                InputManager.MoveMouseTo(this.ChildrenOfType<SelectionBoxScaleHandle>().Single(s => s.Anchor == rotationHandle.Anchor));
            });
            AddUntilStep("rotation handle shown", () => rotationHandle.Alpha == 1);

            AddStep("move mouse away", () => InputManager.MoveMouseTo(selectionBox));
            AddUntilStep("handle hidden", () => rotationHandle.Alpha == 0);
        }

        [Test]
        public void TestHoverRotationHandleFromScaleHandle()
        {
            SelectionBoxRotationHandle rotationHandle = null;

            AddStep("retrieve rotation handle", () => rotationHandle = this.ChildrenOfType<SelectionBoxRotationHandle>().First());

            AddAssert("rotation handle hidden", () => rotationHandle.Alpha == 0);
            AddStep("hover over closest scale handle", () =>
            {
                InputManager.MoveMouseTo(this.ChildrenOfType<SelectionBoxScaleHandle>().Single(s => s.Anchor == rotationHandle.Anchor));
            });
            AddUntilStep("rotation handle shown", () => rotationHandle.Alpha == 1);
            AddAssert("rotation handle not hovered", () => !rotationHandle.IsHovered);

            AddStep("hover over rotation handle", () => InputManager.MoveMouseTo(rotationHandle));
            AddAssert("rotation handle still shown", () => rotationHandle.Alpha == 1);
            AddAssert("rotation handle hovered", () => rotationHandle.IsHovered);

            AddStep("move mouse away", () => InputManager.MoveMouseTo(selectionBox));
            AddUntilStep("handle hidden", () => rotationHandle.Alpha == 0);
        }

        [Test]
        public void TestHoldingScaleHandleHidesCorrespondingRotationHandle()
        {
            SelectionBoxRotationHandle rotationHandle = null;

            AddStep("retrieve rotation handle", () => rotationHandle = this.ChildrenOfType<SelectionBoxRotationHandle>().First());

            AddAssert("rotation handle hidden", () => rotationHandle.Alpha == 0);
            AddStep("hover over closest scale handle", () =>
            {
                InputManager.MoveMouseTo(this.ChildrenOfType<SelectionBoxScaleHandle>().Single(s => s.Anchor == rotationHandle.Anchor));
            });
            AddUntilStep("rotation handle shown", () => rotationHandle.Alpha == 1);
            AddStep("hold scale handle", () => InputManager.PressButton(MouseButton.Left));
            AddUntilStep("rotation handle hidden", () => rotationHandle.Alpha == 0);

            int i;
            ScheduledDelegate mouseMove = null;

            AddStep("start dragging", () =>
            {
                i = 0;

                mouseMove = Scheduler.AddDelayed(() =>
                {
                    InputManager.MoveMouseTo(selectionBox.ScreenSpaceDrawQuad.TopLeft + Vector2.One * (5 * ++i));
                }, 100, true);
            });
            AddAssert("rotation handle still hidden", () => rotationHandle.Alpha == 0);

            AddStep("end dragging", () => mouseMove.Cancel());
            AddAssert("rotation handle still hidden", () => rotationHandle.Alpha == 0);
            AddStep("unhold left", () => InputManager.ReleaseButton(MouseButton.Left));
            AddUntilStep("rotation handle shown", () => rotationHandle.Alpha == 1);
            AddStep("move mouse away", () => InputManager.MoveMouseTo(selectionBox, new Vector2(20)));
            AddUntilStep("rotation handle hidden", () => rotationHandle.Alpha == 0);
        }

        /// <summary>
        /// Tests that hovering over two handles instantaneously from one to another does not crash or cause issues to the visibility state.
        /// </summary>
        [Test]
        public void TestHoverOverTwoHandlesInstantaneously()
        {
            AddStep("hover over top-left scale handle", () =>
                InputManager.MoveMouseTo(this.ChildrenOfType<SelectionBoxScaleHandle>().Single(s => s.Anchor == Anchor.TopLeft)));
            AddStep("hover over top-right scale handle", () =>
                InputManager.MoveMouseTo(this.ChildrenOfType<SelectionBoxScaleHandle>().Single(s => s.Anchor == Anchor.TopRight)));
            AddUntilStep("top-left rotation handle hidden", () =>
                this.ChildrenOfType<SelectionBoxRotationHandle>().Single(r => r.Anchor == Anchor.TopLeft).Alpha == 0);
            AddUntilStep("top-right rotation handle shown", () =>
                this.ChildrenOfType<SelectionBoxRotationHandle>().Single(r => r.Anchor == Anchor.TopRight).Alpha == 1);
        }
    }
}