using Annulus;
using Azimuth;
using Clave;
using Glass.Editing;
using System;

namespace Glass.Testbed.TestCases.Text
{
    /// <summary>
    /// TextBoxes over a spread of behaviors, typed into, selected with the mouse or keyboard, and scrolled.  A readout
    /// reports every OnTextChanged and OnSubmit.
    /// </summary>
    public class TextBoxTestCase : TestCase
    {
        private const int BoxWidth = 260;

        // One instance for every box but the Readline one, the way an app shares one across its whole UI.
        private readonly TextBoxBehavior sharedBehavior = new TextBoxBehavior();

        private Label readout;


        private TextBox BuildBox(string debugName, string text, TextBoxBehavior behavior,
            int maxLength = EditBuffer.NoLimit)
        {
            var box = new TextBox(behavior, maxLength) { DebugName = debugName, TextBoxMaterial = Widgets.TextBox };
            box.TextCursor = CursorExtraMaterials.Text;
            box.Bounds = Rect.FromPositionAndSize(Vector.Zero, Widgets.TextBoxSizeFor(BoxWidth));
            box.Text = text;
            box.Buffer.ClearHistory();
            box.OnTextChanged += (changed, _) =>
                readout.Text = $"OnTextChanged: {changed.DebugName} is \"{changed.Text}\"";
            box.OnSubmit += (TextBox submitted, in KeyboardSnapshot _, KeyboardManager __) =>
                readout.Text = $"OnSubmit: {submitted.DebugName} had \"{submitted.Text}\"";
            return box;
        }

        /// <summary>
        /// A row of <paramref name="box"/> with <paramref name="description"/> beside it.
        /// </summary>
        private void AddRow(TextBox box, string description)
        {
            var caption = new Label(Widgets.SmallCaptionStyle, description, Constraints.Unbounded);
            Vector captionSize = caption.Bounds.Size;

            Rect row = ContentAggregator.NewRow(Math.Max(box.Bounds.Height, captionSize.Y));
            Rect boxSlot = row.NewCol(box.Bounds.Width, margin: Gutter);
            box.Bounds = box.Bounds.WithPosition(boxSlot.TopLeft);
            Add(box);

            caption.Bounds = caption.Bounds.WithPosition(row.TopLeft + new Vector(0, (row.Height - captionSize.Y) / 2));
            Add(caption);
        }

        protected override void Populate()
        {
            AddCaption("Click a box to type in it.  Drag to select, double click for a word, triple click for all.");
            AddCaption("Arrows, Home, End and Ctrl+arrows move (Shift extends).  Tab and Shift+Tab change box.");
            AddCaption("Ctrl+C, X and V, or Ctrl+Insert, Shift+Delete and Shift+Insert, copy, cut and paste.");
            AddCaption("Ctrl+Z undoes a word at a time, and Ctrl+Y or Ctrl+Shift+Z redoes.");
            AddCaption("A browser pastes through its own paste event, and may ask permission to copy.");

            readout = new Label(Widgets.CaptionStyle, "Nothing yet");
            readout.Bounds = ContentAggregator.NewRow(readout.PreferredSize(Constraints.Unbounded).Y);
            Add(readout);

            AddRow(BuildBox("plain", "Hello, world", sharedBehavior), "Windows keys");

            AddRow(BuildBox("long", "The quick brown fox jumps over the lazy dog, and then keeps running",
                    sharedBehavior),
                "Text wider than the box scrolls to keep the caret in view");

            AddRow(BuildBox("short", "12345", sharedBehavior, maxLength: 8), "At most eight chars");

            var readline = new TextBoxBehavior { Bindings = EditBindings.Readline };
            AddRow(BuildBox("readline", "Ctrl+A, E, B, F, K, U, W", readline),
                "Readline keys: Ctrl+A and Ctrl+E for line start and end, Ctrl+K and Ctrl+U to kill");

            var steady = new TextBoxBehavior { BlinkInterval = Amphora.Duration.Zero };
            AddRow(BuildBox("steady", "No blinking caret", steady), "A caret that never blinks");

            TextBox disabled = BuildBox("disabled", "Can't be edited", sharedBehavior);
            disabled.Enabled = false;
            AddRow(disabled, "Disabled");

            AddRow(BuildBox("empty", "", sharedBehavior), "Empty");

            TextBox multiline = BuildBox("multiline",
                "Enter adds a line and Ctrl+Enter submits.\n\nLong lines wrap at the edge of the box, and the box " +
                "scrolls down by lines to keep the caret in view.\n\nPageUp and PageDown move a page.  The wheel, " +
                "the bar and a drag past the top or bottom scroll without moving the caret.\n\nThe bar's room is " +
                "kept from the start, so the text never rewraps when the bar is needed.",
                new TextBoxBehavior { Multiline = true });
            Scalar barWidth = Widgets.TextBox.ScrollBar.Value.PreferredThickness(Orientation.Vertical);
            Scalar fourLines = Widgets.FieldTextStyle.SingleLineHeight * 4;
            multiline.Bounds = Rect.FromPositionAndSize(Vector.Zero,
                Widgets.TextBox.Background.BoundsSizeFor(new Vector(BoxWidth + barWidth, fourLines)));
            AddRow(multiline, "Multiline, four lines tall, with a scroll bar");

            TextBox noWrap = BuildBox("no wrap",
                "Lines end only where Enter ended them, and the box scrolls sideways instead.\n\nShift and the " +
                "wheel, the bottom bar and a drag past the left or right edge scroll without moving the caret.\n\n" +
                "Short.\n\nBoth bars keep their room from the start, so neither can make the other appear.",
                new TextBoxBehavior { Multiline = true, Wrap = false });
            Scalar acrossWidth = Widgets.TextBox.HorizontalScrollBar.Value.PreferredThickness(Orientation.Horizontal);
            noWrap.Bounds = Rect.FromPositionAndSize(Vector.Zero,
                Widgets.TextBox.Background.BoundsSizeFor(new Vector(BoxWidth + barWidth, fourLines + acrossWidth)));
            AddRow(noWrap, "Multiline that doesn't wrap, with both scroll bars");

            TextBox noWrapRight = BuildBox("no wrap, right aligned",
                "Right aligned text starts scrolled to its right end.\nA short line sits against the right edge.\n" +
                "Scroll left to see the starts of the longer lines of this text.",
                new TextBoxBehavior { Multiline = true, Wrap = false });
            noWrapRight.TextBoxMaterial = Widgets.TextBox with
            {
                Text = Widgets.TextBox.Text with { HorizontalAlignment = Alignment.Horizontal.Right },
            };
            noWrapRight.Bounds = noWrap.Bounds;
            AddRow(noWrapRight, "The same, right aligned");
        }
    }
}