using System.Numerics;
using Dalamud.Bindings.ImGui;
using HellionChat.Util;

namespace HellionChat.Ui.StyleEngine.Widgets;

// Visual state of a list row. Deliberately carries no Tab: v1.11.0 swaps the
// sidebar from tab rows to channel rows and should only have to change the
// caller, not the chrome.
internal readonly record struct RowVisualState
{
    public RowVisualState() { }

    public bool IsActive { get; init; }
    public float HoverAmount { get; init; }
    public uint SurfaceHoverAbgr { get; init; }
    public uint SurfaceActiveAbgr { get; init; }
    public uint AccentAbgr { get; init; }
    public uint BorderAbgr { get; init; }
}

internal readonly record struct RowStyle
{
    public RowStyle() { }

    public float AccentBarWidth { get; init; } = 2f;
    public bool DrawSeparator { get; init; } = true;
}

internal static class Row
{
    // Painted before icon and label, and strictly with draw-list calls only:
    // TabContextMenu binds to the last submitted item, so an interactive widget
    // between the row button and the popup call would steal its right-click.
    internal static void Draw(
        Vector2 origin,
        Vector2 size,
        RowVisualState state,
        RowStyle? styleOverride = null
    )
    {
        if (size.X <= 0f || size.Y <= 0f)
            return;

        var style = styleOverride ?? new RowStyle();
        var dl = ImGui.GetWindowDrawList();
        var max = origin + size;

        // Idle rows draw no fill at all. GlobalStyleScope zeroes ChildBg below
        // full window opacity so WindowBg alone carries the coverage, and the
        // default is 0.85 -- an opaque fill per row would make the sidebar a
        // solid block inside a translucent window.
        if (state.IsActive)
            dl.AddRectFilled(origin, max, state.SurfaceActiveAbgr);

        if (state.HoverAmount > 0f)
            dl.AddRectFilled(
                origin,
                max,
                ColourUtil.ApplyAlpha(state.SurfaceHoverAbgr, state.HoverAmount)
            );

        if (state.IsActive && style.AccentBarWidth > 0f)
        {
            var barWidth = style.AccentBarWidth * Metrics.Scale;
            dl.AddRectFilled(origin, new Vector2(origin.X + barWidth, max.Y), state.AccentAbgr);
        }

        if (style.DrawSeparator)
            dl.AddLine(
                new Vector2(origin.X, max.Y - 1f),
                new Vector2(max.X, max.Y - 1f),
                state.BorderAbgr,
                Metrics.Scale
            );
    }
}