using Amphora;
using Annulus;
using Azimuth;
using Clave;
using System.Collections.Generic;
using Prism;

namespace Glass.Testbed.TestCases.Controls
{
    /// <summary>
    /// Overlapping Windows to drag, resize, raise and close, one with a menu bar, with a button bringing back
    /// whatever was closed.  The active window's title bar is blue, the others' grey.
    /// </summary>
    public class WindowTestCase : TestCase
    {
        private const int StageHeight = 360;

        private static readonly WindowMaterial Frame = new WindowMaterial
        {
            Background = UiPacksheetMaterials.Panel,
            TitleBar = UiPacksheetMaterials.BlueFlatPanel,
            Caption = Material.Invisible,
            Content = Material.Invisible,
            CloseButton = Widgets.CloseButton,
        };

        // The pack's grey twin of the blue title bar stands in for desaturating it, which tinting can't do.  Tinted
        // darker, since the white title text is unreadable on it as drawn.
        private static readonly WindowMaterial InactiveFrame = Frame with
        {
            TitleBar = UiPacksheetMaterials.FlatPanel with { TintColor = Colors.Gray },
        };

        private static readonly string[] FileMenuItems = { "Close" };

        private readonly List<Window> windows = new List<Window>();


        private static void AddContentSizeReadout(Window window, ControlContainer into)
        {
            var readout = new Label(Widgets.FieldTextStyle, "")
            {
                DebugName = "content size readout",
                Bounds = Rect.FromPositionAndSize(Vector.Zero, new Vector(160, 40)),
            };
            into.Add(readout);

            void ShowContentSize(Vector contentSize)
            {
                readout.Text = $"{contentSize.X:F0} x {contentSize.Y:F0}";
            }

            ShowContentSize(window.ContentSize);
            window.OnContentResized += ShowContentSize;
        }

        private Window AddWindow(string title, Window window, Rect bounds)
        {
            window.DebugName = title;

            void ShowActive(bool active)
            {
                window.WindowMaterial = active ? Frame : InactiveFrame;
            }

            ShowActive(window.FocusScope.Active);
            window.FocusScope.OnActiveChanged += ShowActive;

            window.ResizeCursors = ResizeCursorMaterials.ByZone;
            window.MoveCursor = CursorExtraMaterials.Move;
            window.Caption.Material = Material.Invisible;
            window.TitleStyle = Widgets.WindowTitleStyle;
            window.Title = title;
            window.Bounds = bounds;

            new Label(Widgets.CloseButtonLabelStyle, "x").FillParent(window.CloseButton);

            Add(window);
            windows.Add(window);
            return window;
        }

        private static Label NewMenuLabel(StringView text)
        {
            return new Label(Widgets.MenuLabelStyle, text, Constraints.Unbounded);
        }

        /// <summary>
        /// Returns the size of a header that fits `label` in either of its states.
        /// </summary>
        private static Vector MenuHeaderSizeFor(Label label)
        {
            return Vector.Max(
                Widgets.MenuHeader.BoundsSizeFor(label.Bounds.Size),
                Widgets.OpenMenuHeader.BoundsSizeFor(label.Bounds.Size));
        }

        private static MenuButton NewFileMenu(Window window, MenuBar menuBar, Label label)
        {
            var header = new MenuButton(ButtonBehavior.Default)
            {
                DebugName = "file menu",
                Group = menuBar.Group,
                UncheckedMaterial = Widgets.MenuHeader,
                CheckedMaterial = Widgets.OpenMenuHeader,
                Bounds = Rect.FromPositionAndSize(Vector.Zero, MenuHeaderSizeFor(label)),
            };
            label.FillParent(header);
            header.Popup.DropdownPopupMaterial = Widgets.PopupList;
            header.Rebuild(FileMenuItems, item => NewMenuLabel(item));
            header.OnItemClicked += _ => window.Close();
            return header;
        }

        protected override void Populate()
        {
            AddCaption("Drag a title bar to move, an edge or corner to resize; x or File > Close closes a window");

            Button reopen = new Label(Widgets.ButtonLabelStyle, "Reopen closed windows", Constraints.Unbounded)
                .WrapIn(UiPacksheetMaterials.Button, ButtonBehavior.Default);
            reopen.DebugName = "reopen button";
            reopen.OnActivate += delegate (ButtonBase _, in KeyboardSnapshot __, KeyboardManager ___)
            {
                foreach (Window window in windows)
                {
                    window.Visible = true;
                }
            };
            reopen.Bounds = Rect.FromPositionAndSize(
                ContentAggregator.NewRow(reopen.Bounds.Height).TopLeft, reopen.Bounds.Size);
            Add(reopen);

            Rect stage = ContentAggregator.NewRow(StageHeight);

            Window resizable = AddWindow("Resizable window", new Window(),
                Rect.FromPositionAndSize(stage.TopLeft + new Vector(20, 20), new Vector(260, 180)));
            AddContentSizeReadout(resizable, resizable.CanvasChildren);

            AddWindow("Fixed size, no close button", new Window { Resizable = false, ShowCloseButton = false },
                Rect.FromPositionAndSize(stage.TopLeft + new Vector(160, 110), new Vector(260, 140)));

            Label fileLabel = NewMenuLabel("File");
            Window withMenu = AddWindow("With a menu bar", new Window(),
                Rect.FromPositionAndSize(stage.TopLeft + new Vector(460, 30), new Vector(280, 200)));
            (MenuBar menuBar, Panel body) = Widgets.AddMenuBar(withMenu, MenuHeaderSizeFor(fileLabel).Y);
            menuBar.CanvasChildren.Add(NewFileMenu(withMenu, menuBar, fileLabel));
            AddContentSizeReadout(withMenu, body.CanvasChildren);
        }
    }
}