neiam /gitgud

defmodule GitGudWeb.RepoLive.Languages do
  use GitGudWeb, :live_view

  alias GitGud.Repositories
  alias GitGud.Repositories.Storage

  @impl true
  def mount(%{"owner" => owner, "name" => name} = params, _session, socket) do
    repo =
      Repositories.get_repository_by_path!(owner, name)
      |> GitGud.Repo.preload([:owner, :organization])

    ref = params["ref"] || repo.default_branch

    {sha, stats, status} = resolve_stats(repo, ref)

    {:ok,
     socket
     |> assign(:repo, repo)
     |> assign(:handle, Storage.repo_handle(repo))
     |> GitGudWeb.RepoLive.Header.assign_chrome(repo)
     |> assign(:current_ref, ref)
     |> assign(:head_sha, sha)
     |> assign(:stats, stats)
     |> assign(:status, status)
     |> assign(:page_title, "Languages — #{owner}/#{name}")}
  end

  defp resolve_stats(repo, ref) do
    case Repositories.resolve(repo, ref) do
      {:ok, sha} ->
        case Repositories.get_language_stats(repo, sha) do
          {:ok, stats} ->
            {sha, stats, :ready}

          :not_computed ->
            _ =
              GitGud.Repositories.Workers.LanguageStats.new_job(%{
                repository_id: repo.id,
                sha: sha
              })
              |> Oban.insert()

            {sha, nil, :pending}
        end

      _ ->
        {nil, nil, :empty}
    end
  end

  @impl true
  def render(assigns) do
    ~H"""
    <Layouts.app flash={@flash} current_scope={@current_scope}>
      <div class="space-y-4">
        <GitGudWeb.RepoLive.Header.header
          repo={@repo}
          handle={@handle}
          current_scope={@current_scope}
          has_packages?={@has_packages?}
          can_admin?={@can_admin?}
          latest_run={@latest_run}
        />
        <header>
          <h1 class="text-xl font-semibold">Stats</h1>
        </header>

        <GitGudWeb.RepoLive.StatsTabs.tabs
          active={:languages}
          handle={@handle}
          repo={@repo}
        />

        <p class="text-xs opacity-60 font-mono">
          on {@current_ref}<%= if @head_sha do %>
            · {GitGud.Git.short(@head_sha)}
          <% end %>
        </p>

        <%= case @status do %>
          <% :empty -> %>
            <p class="text-sm opacity-70">This branch or repository is empty.</p>

          <% :pending -> %>
            <div class="rounded-box border border-base-300 bg-base-200 p-4 text-sm space-y-2">
              <p>Language stats are still being computed.</p>
              <p class="text-xs opacity-70">
                Refresh in a moment — a background job is walking the tree and tallying
                bytes per detected language.
              </p>
            </div>

          <% :ready -> %>
            <.bar stats={@stats} />

            <table class="table table-sm">
              <thead>
                <tr>
                  <th class="w-6"></th>
                  <th>Language</th>
                  <th class="text-right">Percent</th>
                  <th class="text-right">Bytes</th>
                  <th class="text-right">Files</th>
                </tr>
              </thead>
              <tbody>
                <tr :for={s <- @stats.languages}>
                  <td>
                    <span
                      class="inline-block size-3 rounded-full"
                      style={"background-color: " <> GitGud.LanguageColors.for(s.language) <> ";"}
                    />
                  </td>
                  <td class="font-mono">{s.language}</td>
                  <td class="text-right">{percent(s.bytes, @stats.total_bytes)}%</td>
                  <td class="text-right font-mono opacity-70">{format_bytes(s.bytes)}</td>
                  <td class="text-right opacity-70">{s.files}</td>
                </tr>
              </tbody>
              <tfoot>
                <tr class="text-xs opacity-60">
                  <td colspan="2">Total</td>
                  <td class="text-right">100%</td>
                  <td class="text-right font-mono">{format_bytes(@stats.total_bytes)}</td>
                  <td class="text-right">{@stats.file_count}</td>
                </tr>
              </tfoot>
            </table>
            <p :if={@stats[:computed_at]} class="text-xs opacity-50">
              Computed {Calendar.strftime(@stats.computed_at, "%Y-%m-%d %H:%M UTC")}
            </p>
        <% end %>
      </div>
    </Layouts.app>
    """
  end

  attr :stats, :map, required: true

  defp bar(assigns) do
    ~H"""
    <div class="flex w-full overflow-hidden rounded bg-base-300" style="height: 1em;">
      <div
        :for={s <- @stats.languages}
        class="h-full"
        style={
          "width: #{percent(s.bytes, @stats.total_bytes)}%; background-color: " <>
            GitGud.LanguageColors.for(s.language) <> ";"
        }
        title={"#{s.language} · #{percent(s.bytes, @stats.total_bytes)}%"}
      />
    </div>
    """
  end

  defp percent(_b, 0), do: 0.0
  defp percent(b, total), do: Float.round(b * 100 / total, 2)

  defp format_bytes(b) when b < 1024, do: "#{b} B"
  defp format_bytes(b) when b < 1_000_000, do: "#{Float.round(b / 1024, 1)} KiB"
  defp format_bytes(b), do: "#{Float.round(b / 1_048_576, 2)} MiB"
end