namespace Htmx.ApiDemo.Templates.Components;

/// <summary>
/// CSS-native DropdownMenu using &lt;details&gt;/&lt;summary&gt;.
/// Position: "left-0 top-full mt-1" (default) | "right-0 top-full mt-1" | etc.
/// Items: pre-built HTML — use BuildItem() helper for consistent styling.
/// </summary>
public sealed class DropdownMenu : DropdownMenuBase
{
    private const string ItemClasses =
        "relative flex w-full cursor-pointer select-none items-center rounded-sm px-2 py-1.5 text-sm " +
        "outline-none transition-colors hover:bg-accent hover:text-accent-foreground " +
        "focus:bg-accent focus:text-accent-foreground disabled:pointer-events-none disabled:opacity-50";

    private readonly byte[] _triggerClassesData;
    private readonly byte[] _triggerData;
    private readonly byte[] _positionData;
    private readonly byte[] _itemsData;

    public DropdownMenu(
        IHtmxComponent trigger,
        IEnumerable<(string Label, string Href, bool IsSeparator)> items,
        string position = "left-0 top-full mt-1")
    {
        // Render trigger to bytes
        var writer = new System.Buffers.ArrayBufferWriter<byte>();
        trigger.Render(new HtmxRenderContext(writer));
        _triggerData        = writer.WrittenSpan.ToArray();
        _triggerClassesData = []; // trigger already supplies its own classes
        _positionData       = position.ToUtf8Bytes();

        var sb = new System.Text.StringBuilder();
        foreach (var (label, href, isSeparator) in items)
        {
            if (isSeparator)
            {
                sb.Append("""<div class="-mx-1 my-1 h-px bg-border"></div>""");
            }
            else if (string.IsNullOrEmpty(href))
            {
                sb.Append($"""<button type="button" class="{ItemClasses}">{label}</button>""");
            }
            else
            {
                sb.Append($"""<a href="{href}" class="{ItemClasses}">{label}</a>""");
            }
        }
        _itemsData = sb.ToString().ToUtf8Bytes();
    }

    protected override void RenderTriggerClasses(HtmxRenderContext ctx) => ctx.Writer.WriteUtf8(_triggerClassesData);
    protected override void RenderTrigger(HtmxRenderContext ctx)        => ctx.Writer.WriteUtf8(_triggerData);
    protected override void RenderPosition(HtmxRenderContext ctx)       => ctx.Writer.WriteUtf8(_positionData);
    protected override void RenderItems(HtmxRenderContext ctx)          => ctx.Writer.WriteUtf8(_itemsData);
}