defmodule BDS.Desktop.ShellLive.PanelRenderer do
  @moduledoc false

  use Phoenix.Component

  alias BDS.Desktop.ShellData
  alias BDS.Git
  alias BDS.Media
  alias BDS.Media.Media, as: MediaRecord
  alias BDS.PostLinks
  alias BDS.Posts
  alias BDS.Posts.Post
  alias BDS.UI.TaskGrouping
  use Gettext, backend: BDS.Gettext

  @doc "Render the active panel tab body."
  def render_panel_body(assigns) do
    case assigns.workbench.panel.active_tab do
      :tasks -> render_task_entries(assigns)
      :output -> render_output_entries(assigns)
      :post_links -> render_post_links(assigns)
      :git_log -> render_git_log(assigns)
      other -> render_generic_panel(assigns, other)
    end
  end

  @doc "Render the editor toolbar for the current tab."
  def render_editor_toolbar(assigns) do
    buttons = editor_toolbar_buttons(assigns.current_tab)
    assigns = assign(assigns, :editor_toolbar_buttons, buttons)

    ~H"""
    <%= if Enum.any?(@editor_toolbar_buttons) do %>
      <div class="editor-toolbar flex items-center gap-2">
        <%= for button <- @editor_toolbar_buttons do %>
          <button
            class={["editor-toolbar-button inline-flex items-center justify-center", if(button.destructive, do: "is-destructive")]}
            data-testid="editor-toolbar-overlay-button"
            type="button"
            phx-click="open_overlay"
            phx-value-kind={button.kind}
          >
            <%= button.label %>
          </button>
        <% end %>
      </div>
    <% end %>
    """
  end

  defp render_task_entries(assigns) do
    entries = TaskGrouping.build_task_entries(Map.get(assigns.task_status, :tasks, []))
    collapsed = Map.get(assigns, :collapsed_task_groups) || MapSet.new()

    assigns =
      assigns
      |> assign(:task_entries, entries)
      |> assign(:collapsed_task_groups, collapsed)

    ~H"""
    <%= if Enum.empty?(@task_entries) do %>
      <div class="panel-entry ui-panel-entry panel-empty-state ui-empty-state">
        <strong><%= dgettext("ui", "Tasks") %></strong>
        <span><%= dgettext("ui", "No background tasks running") %></span>
      </div>
    <% else %>
      <div class="task-list flex flex-col gap-2">
        <%= for entry <- @task_entries do %>
          <%= case entry do %>
            <% {:single, task} -> %>
              {render_task_row(assigns, task, false)}
            <% {:group, group_id, group_name, tasks} -> %>
              {render_task_group(assigns, group_id, group_name, tasks)}
          <% end %>
        <% end %>
      </div>
    <% end %>
    """
  end

  defp render_task_group(assigns, group_id, group_name, tasks) do
    summary = TaskGrouping.summarize_task_group(tasks)
    expanded = not MapSet.member?(assigns.collapsed_task_groups, group_id)

    assigns =
      assigns
      |> assign(:group_id, group_id)
      |> assign(:group_name, group_name)
      |> assign(:group_tasks, tasks)
      |> assign(:group_expanded, expanded)
      |> assign(:group_meta, task_group_meta(summary))

    ~H"""
    <div class="task-group flex flex-col">
      <button
        class="panel-entry ui-panel-entry task-entry task-group-toggle flex w-full items-center gap-2 text-left"
        type="button"
        phx-click="toggle_task_group"
        phx-value-group={@group_id}
        aria-expanded={to_string(@group_expanded)}
      >
        <span class="task-group-chevron">{if @group_expanded, do: "▾", else: "▸"}</span>
        <strong class="task-group-title"><%= @group_name %> (<%= length(@group_tasks) %>)</strong>
        <span class="task-group-meta text-muted text-xs"><%= @group_meta %></span>
      </button>
      <%= if @group_expanded do %>
        <%= for task <- @group_tasks do %>
          {render_task_row(assigns, task, true)}
        <% end %>
      <% end %>
    </div>
    """
  end

  defp render_task_row(assigns, task, is_child) do
    assigns =
      assigns
      |> assign(:task, task)
      |> assign(:task_child?, is_child)

    ~H"""
    <div class={["panel-entry", "ui-panel-entry", "task-entry", "flex flex-col gap-2", if(@task_child?, do: "ml-4")]}>
      <div class="task-entry-header flex items-center justify-between gap-2">
        <strong><%= @task.name %></strong>
        <span class={"task-status task-status-#{@task.status}"}><%= Map.get(@task, :status_label, @task.status |> to_string() |> String.capitalize()) %></span>
      </div>
      <span><%= @task.message || @task.group_name || "" %></span>
      <%= if is_number(@task.progress) do %>
        <div class="task-progress-row">
          <progress max="1" value={@task.progress}></progress>
          <span><%= Map.get(@task, :progress_label, progress_percent(@task.progress)) %></span>
        </div>
      <% end %>
      <%= if @task.status == :running do %>
        <div class="task-entry-actions flex justify-end">
          <button
            class="ui-button ui-button-secondary inline-flex items-center px-2 py-1 text-xs"
            data-testid="cancel-task-button"
            type="button"
            phx-click="cancel_task"
            phx-value-id={@task.id}
          >
            <%= dgettext("ui", "Cancel") %>
          </button>
        </div>
      <% end %>
    </div>
    """
  end

  # "NN% · X Running · Y Pending" — the breakdown only lists non-zero counts,
  # like the old app's summarizeTaskGroup rendering.
  defp task_group_meta(summary) do
    parts =
      []
      |> maybe_append_breakdown(summary.running, dgettext("ui", "Running"))
      |> maybe_append_breakdown(summary.pending, dgettext("ui", "Pending"))

    suffix = if parts == [], do: "", else: " · " <> Enum.join(parts, " · ")
    progress_percent(summary.progress) <> suffix
  end

  defp maybe_append_breakdown(parts, count, _label) when count <= 0, do: parts

  defp maybe_append_breakdown(parts, count, label),
    do: parts ++ ["#{count} #{label}"]

  defp render_output_entries(assigns) do
    ~H"""
    <%= if Enum.empty?(@output_entries) do %>
      <div class="panel-entry ui-panel-entry panel-empty-state ui-empty-state output-list">
        <strong><%= dgettext("ui", "Output") %></strong>
        <span><%= dgettext("ui", "No shell output yet") %></span>
      </div>
    <% else %>
      <div class="output-toolbar flex shrink-0 justify-end">
        <button
          class="ui-button ui-button-secondary inline-flex items-center px-2 py-1 text-xs"
          data-testid="copy-output-button"
          type="button"
          phx-click="copy_output"
        >
          <%= dgettext("ui", "Copy") %>
        </button>
      </div>
      <div class="output-list flex flex-col gap-2">
        <%= for entry <- @output_entries do %>
          <div class={[
            "panel-entry",
            "ui-panel-entry",
            "output-entry",
            if(Map.get(entry, :level) == "error", do: "output-entry-error")
          ]}>
            <strong><%= entry.title %></strong>
            <span><%= entry.message %></span>
            <%= if present?(entry.details) do %>
              <span><%= entry.details %></span>
            <% end %>
          </div>
        <% end %>
      </div>
    <% end %>
    """
  end

  defp render_post_links(assigns) do
    panel_links = assigns[:panel_post_links] || %{backlinks: [], outlinks: []}

    assigns =
      assigns
      |> assign(:backlinks, Map.get(panel_links, :backlinks, []))
      |> assign(:outlinks, Map.get(panel_links, :outlinks, []))

    ~H"""
    <%= if Enum.empty?(@backlinks) and Enum.empty?(@outlinks) do %>
      <div class="panel-entry ui-panel-entry panel-empty-state ui-empty-state">
        <strong><%= dgettext("ui", "Post Links") %></strong>
        <span><%= dgettext("ui", "No post links yet") %></span>
      </div>
    <% else %>
      <div class="git-log-list flex flex-col gap-2">
        <%= if Enum.any?(@backlinks) do %>
          <div class="panel-entry ui-panel-entry"><strong><%= dgettext("ui", "Backlinks") %></strong></div>
          <%= for entry <- @backlinks do %>
            <button
              class="panel-entry ui-panel-entry task-entry"
              type="button"
              phx-click="pin_sidebar_item"
              phx-value-route="post"
              phx-value-id={entry.id}
              phx-value-title={entry.title}
              phx-value-subtitle="linked post"
            >
              <strong><%= entry.title %></strong>
              <span><%= entry.text %></span>
            </button>
          <% end %>
        <% end %>

        <%= if Enum.any?(@outlinks) do %>
          <div class="panel-entry ui-panel-entry"><strong><%= dgettext("ui", "Links To") %></strong></div>
          <%= for entry <- @outlinks do %>
            <button
              class="panel-entry ui-panel-entry task-entry"
              type="button"
              phx-click="pin_sidebar_item"
              phx-value-route="post"
              phx-value-id={entry.id}
              phx-value-title={entry.title}
              phx-value-subtitle="linked post"
            >
              <strong><%= entry.title %></strong>
              <span><%= entry.text %></span>
            </button>
          <% end %>
        <% end %>
      </div>
    <% end %>
    """
  end

  defp render_git_log(assigns) do
    entries = assigns[:panel_git_entries] || []
    assigns = assign(assigns, :git_entries, entries)

    ~H"""
    <%= if Enum.empty?(@git_entries) do %>
      <div class="git-log-list flex flex-col gap-2">
        <div class="panel-entry ui-panel-entry panel-empty-state ui-empty-state">
          <strong><%= dgettext("ui", "Git Log") %></strong>
          <span><%= dgettext("ui", "No git history yet") %></span>
        </div>
      </div>
    <% else %>
      <div class="git-log-list">
        <%= for entry <- @git_entries do %>
          <div class="panel-entry ui-panel-entry task-entry">
            <strong><%= short_commit_hash(entry.hash) %> <%= entry.subject || dgettext("ui", "No commit subject") %></strong>
            <span><%= entry.hash %></span>
          </div>
        <% end %>
      </div>
    <% end %>
    """
  end

  defp render_generic_panel(assigns, tab) do
    assigns = assign(assigns, :panel_label, ShellData.route_label(tab))

    ~H"""
    <div class="panel-entry ui-panel-entry">
      <strong><%= @panel_label %></strong>
      <span><%= dgettext("ui", "The shared lower panel is available for tasks, output, git details, and editor-specific diagnostics.") %></span>
    </div>
    """
  end

  def fetch_post_link_entries(assigns) do
    case assigns.current_tab do
      %{type: :post, id: post_id} ->
        %{
          backlinks: related_posts(PostLinks.list_incoming_links(post_id), :source_post_id),
          outlinks: related_posts(PostLinks.list_outgoing_links(post_id), :target_post_id)
        }

      _other ->
        %{backlinks: [], outlinks: []}
    end
  end

  defp related_posts(links, key) do
    Enum.map(links, fn link ->
      case Posts.get_post(Map.fetch!(link, key)) do
        %Post{} = post ->
          %{
            id: post.id,
            title: post.title || post.slug || post.id,
            text: link.link_text || post.slug || post.id
          }

        _other ->
          nil
      end
    end)
    |> Enum.reject(&is_nil/1)
  end

  def fetch_git_log_entries(assigns) do
    case git_history_target(assigns.current_tab) do
      nil ->
        []

      {project_id, file_path} ->
        case Git.file_history(project_id, file_path) do
          {:ok, %{commits: commits}} -> commits
          _other -> []
        end
    end
  end

  defp git_history_target(%{type: :post, id: post_id}) do
    case Posts.get_post(post_id) do
      %Post{project_id: project_id, file_path: file_path} when file_path not in [nil, ""] ->
        {project_id, file_path}

      _other ->
        nil
    end
  end

  defp git_history_target(%{type: :media, id: media_id}) do
    case Media.get_media(media_id) do
      %MediaRecord{project_id: project_id, file_path: file_path}
      when file_path not in [nil, ""] ->
        {project_id, file_path}

      _other ->
        nil
    end
  end

  defp git_history_target(_tab), do: nil

  def editor_toolbar_buttons(nil), do: []

  def editor_toolbar_buttons(%{type: :post}) do
    [
      %{kind: "ai_suggestions", label: "AI Suggestions", destructive: false},
      %{kind: "insert_link", label: "Insert Link", destructive: false},
      %{kind: "insert_media", label: "Insert Media", destructive: false},
      %{kind: "language_picker", label: "Translate", destructive: false},
      %{kind: "gallery", label: "Gallery", destructive: false}
    ]
  end

  def editor_toolbar_buttons(%{type: :media}) do
    [
      %{kind: "ai_suggestions", label: "AI Suggestions", destructive: false},
      %{kind: "language_picker", label: "Translate", destructive: false},
      %{kind: "confirm_delete", label: "Delete Media", destructive: true}
    ]
  end

  def editor_toolbar_buttons(%{type: :tags}) do
    [
      %{kind: "confirm_merge", label: "Merge Tags", destructive: false},
      %{kind: "confirm_delete", label: "Delete Tag", destructive: true}
    ]
  end

  def editor_toolbar_buttons(_tab), do: []

  defp short_commit_hash(hash) when is_binary(hash), do: String.slice(hash, 0, 7)
  defp short_commit_hash(_hash), do: "-------"

  # Only called inside the template's `is_number(task.progress)` guard.
  defp progress_percent(progress) when is_number(progress) do
    rounded = progress |> Kernel.*(100) |> Float.round(0) |> trunc()
    "#{rounded}%"
  end

  defp present?(value), do: BDS.Values.present?(value)
end