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

namespace Glass.Testbed
{
    /// <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;

        public TextBoxTestCase(string name) : base(name) { }

        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.Bounds = Rect.FromPositionAndSize(Vector.Zero, Widgets.TextBoxSizeFor(BoxWidth));
            box.Text = text;
            box.OnTextChanged += changed => readout.Text = $"OnTextChanged: {changed.DebugName} is \"{changed.Text}\"";
            box.OnSubmit += submitted => 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("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");
        }
    }
}