@page "/git/{Repository}/log"
@inherits GitPage

<PageTitle>@Repository log — git</PageTitle>

<GitBar Repository="@Repository" Reference="@Current" Tab="log"/>

<main class="git-main">
    @if (Page is not { } page)
    {
        <section class="block">
            <p class="empty">
                @(BranchNames.Count == 0
                    ? $"Nothing has been pushed to {Repository} yet."
                    : $"No revision called {Reference ?? "HEAD"} in {Repository}.")
            </p>
        </section>
    }
    else
    {
        <section class="block">
            <h2 class="block-head">
                <span>log</span>
                <span class="block-note">@Where</span>
            </h2>

            @* A plain GET form: the log is a URL, and narrowing it should produce one you can
               link to. Nothing here needs script. *@
            <div class="block-body">
                <form method="get" action="@($"{RepoLink()}/log")" class="controls">
                    <label>
                        branch
                        <select name="h">
                            @foreach (var branch in BranchNames)
                            {
                                <option value="@branch" selected="@(branch == Current)">@branch</option>
                            }
                        </select>
                    </label>
                    <label>
                        path
                        <input type="text" name="path" value="@Path" placeholder="Blog/Services" size="24"/>
                    </label>
                    <button type="submit">show</button>
                </form>
            </div>

            @if (page.Commits.Count == 0)
            {
                <p class="empty">No commits@(string.IsNullOrEmpty(Path) ? "" : $" touching {Path}").</p>
            }
            else
            {
                <div class="scroll">
                    <table>
                        <thead>
                        <tr>
                            <th>age</th>
                            <th>commit</th>
                            <th class="wide">subject</th>
                            <th class="when-wide">author</th>
                        </tr>
                        </thead>
                        <tbody>
                        @foreach (var commit in page.Commits)
                        {
                            <tr>
                                <td class="dim" title="@Exact(commit.Author.When)">@Age(commit.Author.When)</td>
                                <td class="sha dim"><a href="@CommitLink(commit.Sha)">@commit.ShortSha</a></td>
                                <td class="wide">
                                    <a href="@CommitLink(commit.Sha)" class="subject">@commit.Summary</a>
                                    @if (commit.IsMerge)
                                    {
                                        <span class="ref">merge</span>
                                    }
                                    @foreach (var name in commit.Refs)
                                    {
                                        <span class="ref @(name == Current ? "head" : null)">@name</span>
                                    }
                                </td>
                                <td class="dim when-wide" title="@commit.Author.Email">@commit.Author.Name</td>
                            </tr>
                        }
                        </tbody>
                    </table>
                </div>

                <div class="pager">
                    @if (Skip > 0)
                    {
                        <a href="@LogLink(Current, Path, Math.Max(0, Skip - PageSize))">newer</a>
                    }
                    else
                    {
                        <span>newest</span>
                    }

                    @if (page.HasMore)
                    {
                        <a href="@LogLink(Current, Path, Skip + PageSize)">older</a>
                    }
                    else
                    {
                        <span>oldest</span>
                    }
                </div>
            }
        </section>
    }
</main>

@code {
    private const int PageSize = 50;

    /// <summary>Narrows the log to the commits that touched one file or directory.</summary>
    [SupplyParameterFromQuery(Name = "path")]
    public string? Path { get; set; }

    /// <summary>How many commits to skip — the offset cgit paged with, under the name it used.</summary>
    [SupplyParameterFromQuery(Name = "ofs")]
    public int Skip { get; set; }

    private GitLogPage? Page { get; set; }

    private IReadOnlyList<string> BranchNames { get; set; } = [];

    /// <summary>The branch this page is of, which is HEAD's when the query string named none.</summary>
    private string? Current { get; set; }

    private string Where => string.IsNullOrEmpty(Path) ? Current ?? "" : $"{Current} · {Path}";

    protected override void OnParametersSet()
    {
        Skip = Math.Max(0, Skip);

        // GetRefs lists HEAD's branch first, so the picker's first entry is also what this page
        // defaults to — one repository open rather than two.
        if (Service.GetRefs(Repository) is not { } refs)
        {
            NotFound();
            return;
        }

        BranchNames = refs.Branches.Select(branch => branch.Name).ToArray();
        Current = Reference ?? BranchNames.FirstOrDefault();

        Page = Service.GetLog(Repository, Reference, Path, Skip, PageSize);

        // A repository with branches but nothing at this revision was reached by a bad URL. One
        // with no branches at all is a repository nobody has pushed to, which is not an error.
        if (Page is null && BranchNames.Count > 0) NotFound();
    }
}