@* The one row of chrome a git page gets: where you are on the left, where else you can go on the
   right. Inverted, like a terminal's status line — see git.css. *@

<nav class="git-bar">
    <span class="git-crumbs">
        <a href="/git">git</a>

        @if (Repository is { Length: > 0 })
        {
            <span class="sep">/</span>
            <a href="@RepoHref"><strong>@Repository</strong></a>

            @foreach (var crumb in Path)
            {
                <span class="sep">/</span>
                @if (crumb.Href is null)
                {
                    <strong>@crumb.Name</strong>
                }
                else
                {
                    <a href="@crumb.Href">@crumb.Name</a>
                }
            }
        }
    </span>

    @if (Repository is { Length: > 0 })
    {
        <span class="git-tabs">
            <a class="@Active("log")" href="@($"{RepoHref}/log{Query}")">log</a>
            <a class="@Active("tree")" href="@($"{RepoHref}/tree{Query}")">tree</a>
            <a class="@Active("refs")" href="@($"{RepoHref}/refs")">refs</a>
        </span>
    }
</nav>

@code {
    /// <summary>One step of the path under the repository. A null href is the step you are on.</summary>
    public sealed record Crumb(string Name, string? Href);

    /// <summary>The repository's directory name. Empty on the index, which has no tabs.</summary>
    [Parameter]
    public string? Repository { get; set; }

    /// <summary>Which tab to punch out: <c>log</c>, <c>tree</c> or <c>refs</c>.</summary>
    [Parameter]
    public string? Tab { get; set; }

    /// <summary>The branch the tabs should stay on, when the page is on one.</summary>
    [Parameter]
    public string? Reference { get; set; }

    [Parameter]
    public IReadOnlyList<Crumb> Path { get; set; } = [];

    private string RepoHref => $"/git/{Uri.EscapeDataString(Repository ?? "")}";

    private string Query => string.IsNullOrEmpty(Reference) ? "" : $"?h={Uri.EscapeDataString(Reference)}";

    private string? Active(string tab) => tab == Tab ? "on" : null;
}