defmodule MusicLibraryWeb.Components.Release do
  use MusicLibraryWeb, :live_component

  require Logger

  alias MusicBrainz.Release
  alias MusicLibrary.Records.TracklistPdf
  alias MusicLibrary.ScrobbleActivity
  alias MusicLibraryWeb.Duration
  alias MusicLibraryWeb.ErrorMessages
  alias Phoenix.LiveView.AsyncResult

  def open(id), do: Fluxon.open_dialog(id)

  @impl true
  def mount(socket) do
    {:ok,
     socket
     |> assign(:can_scrobble?, ScrobbleActivity.can_scrobble?())
     |> assign(:release_with_tracks, AsyncResult.loading())
     |> assign(:already_scrobbled, false)
     |> assign(:selected_tracks, MapSet.new())
     |> assign(:form, to_form(%{}, as: :release))
     |> assign(:pending_form_params, nil)}
  end

  @impl true
  def update(%{record: record} = assigns, socket) do
    {:ok,
     socket
     |> assign(assigns)
     |> assign(:release_with_tracks, AsyncResult.loading())
     |> start_async(:release_with_tracks, fn ->
       load_release_with_tracks(record.selected_release_id)
     end)}
  end

  def update(%{already_scrobbled: _already_scrobbled} = assigns, socket) do
    {:ok, assign(socket, assigns)}
  end

  @impl true
  def handle_async(:release_with_tracks, {:ok, {:ok, release}}, socket) do
    socket =
      socket
      |> assign(
        :release_with_tracks,
        AsyncResult.ok(socket.assigns.release_with_tracks, release)
      )
      |> apply_pending_form_params()

    {:noreply, socket}
  end

  def handle_async(:release_with_tracks, {:ok, {:error, reason}}, socket) do
    {:noreply,
     assign(
       socket,
       :release_with_tracks,
       AsyncResult.failed(socket.assigns.release_with_tracks, {:error, reason})
     )}
  end

  def handle_async(:release_with_tracks, {:exit, reason}, socket) do
    {:noreply,
     assign(
       socket,
       :release_with_tracks,
       AsyncResult.failed(socket.assigns.release_with_tracks, {:exit, reason})
     )}
  end

  defp apply_pending_form_params(socket) do
    case socket.assigns.pending_form_params do
      nil ->
        socket

      params ->
        release = socket.assigns.release_with_tracks.result
        new_selected = apply_form_params(release, params, socket.assigns.selected_tracks)

        socket
        |> assign(:selected_tracks, new_selected)
        |> assign(:pending_form_params, nil)
    end
  end

  @impl true
  def render(assigns) do
    ~H"""
    <div>
      <.sheet
        :if={@record.selected_release_id}
        id={@sheet_id}
        placement="right"
        class="min-w-xs sm:min-w-sm"
      >
        <.form
          for={@form}
          id={"#{@sheet_id}-form"}
          phx-target={@myself}
          phx-change="validate"
          phx-auto-recover="recover_form"
        >
          <input type="hidden" name="release[selected_tracks][]" value="" />
          <input type="hidden" name="release[toggle_medium][]" value="" />

          <div class="mt-6 flex items-center justify-between gap-4">
            <label class="cursor-pointer text-lg font-semibold text-zinc-700 dark:text-zinc-300">
              <input
                :if={
                  @can_scrobble? && @release_with_tracks.ok? &&
                    Release.media_count(@release_with_tracks.result) == 1
                }
                type="checkbox"
                id="medium-checkbox-1"
                name="release[toggle_medium][]"
                value="1"
                checked={
                  medium_selected?(
                    Release.get_medium(@release_with_tracks.result, 1),
                    @selected_tracks
                  )
                }
                class="mr-2 size-4 rounded border-gray-300 bg-gray-100 text-blue-600 focus:ring-2 focus:ring-blue-500 dark:border-gray-600 dark:bg-gray-700 dark:ring-offset-gray-800 dark:focus:ring-blue-600"
              />
              {gettext("Tracks")}
            </label>
            <.button_group>
              <.button
                :if={@release_with_tracks.ok?}
                type="button"
                variant="soft"
                size="sm"
                phx-click="print_tracklist"
                phx-target={@myself}
              >
                <span class="sr-only">{gettext("Print tracklist")}</span>
                <.icon name="hero-printer" class="icon" aria-hidden="true" data-slot="icon" />
              </.button>
              <.button
                :if={@can_scrobble? && @release_with_tracks.ok?}
                type="button"
                variant="soft"
                size="sm"
                disabled={@already_scrobbled}
                phx-click={
                  if MapSet.size(@selected_tracks) > 0,
                    do: "scrobble_selected_tracks",
                    else: "scrobble_release"
                }
                phx-target={@myself}
                phx-disable-with={gettext("Scrobbling...")}
              >
                <span class="sr-only">{scrobble_button_label(@selected_tracks)}</span>
                <.icon name="hero-play" class="icon" aria-hidden="true" data-slot="icon" />
              </.button>
              <.button :if={!@can_scrobble?} variant="soft" size="sm" href={LastFm.auth_url()}>
                <span class="sr-only">{gettext("Connect your Last.fm account")}</span>
                <.icon name="hero-link" class="icon" aria-hidden="true" data-slot="icon" />
              </.button>
            </.button_group>
          </div>

          <div :if={@release_with_tracks} class="mt-4 space-y-4">
            <.async_result :let={release_with_tracks} assign={@release_with_tracks}>
              <:loading>
                <div class="mt-48 flex items-center justify-center">
                  <span class="sr-only">{gettext("Loading release with tracks")}</span>
                  <.loading />
                </div>
              </:loading>
              <:failed :let={_failure}>
                <div class="mt-4 text-sm/5 text-zinc-500 dark:text-zinc-400">
                  <.icon
                    name="hero-exclamation-triangle"
                    class="size-5"
                    aria-hidden="true"
                    data-slot="icon"
                  />
                  {gettext("Error loading tracks")}
                  <.button
                    type="button"
                    variant="ghost"
                    size="xs"
                    phx-click={JS.push("load_release_tracks", target: @myself)}
                    class="ml-2 cursor-pointer"
                  >
                    {gettext("Retry")}
                  </.button>
                </div>
              </:failed>
              <.medium
                :for={medium <- release_with_tracks.media}
                can_scrobble?={@can_scrobble?}
                already_scrobbled={@already_scrobbled}
                medium={medium}
                release_artists={release_with_tracks.artists}
                media_count={MusicBrainz.Release.media_count(release_with_tracks)}
                selected_tracks={@selected_tracks}
                myself={@myself}
                record={@record}
              />
            </.async_result>
          </div>
        </.form>
      </.sheet>
    </div>
    """
  end

  attr :medium, Release.Medium, required: true
  attr :release_artists, :list, required: true
  attr :media_count, :integer, required: true
  attr :can_scrobble?, :boolean, required: true
  attr :already_scrobbled, :boolean, required: true
  attr :selected_tracks, :any, required: true
  attr :myself, :any, required: true
  attr :record, :any, default: nil

  def medium(assigns) do
    ~H"""
    <div
      :if={@media_count > 1}
      class="flex items-center justify-between gap-4"
    >
      <label class="md:text-md cursor-pointer text-sm font-semibold text-zinc-700 dark:text-zinc-300">
        <input
          :if={@can_scrobble?}
          type="checkbox"
          id={"medium-checkbox-#{@medium.number}"}
          name="release[toggle_medium][]"
          value={@medium.number}
          checked={medium_selected?(@medium, @selected_tracks)}
          class="mr-2 size-4 rounded border-gray-300 bg-gray-100 text-blue-600 focus:ring-2 focus:ring-blue-500 dark:border-gray-600 dark:bg-gray-700 dark:ring-offset-gray-800 dark:focus:ring-blue-600"
        />
        {medium_title(@medium)}
        <.badge variant="soft" class="text-xs">
          {@medium.format}
        </.badge>
      </label>
      <.button_group>
        <.button
          :if={@record}
          type="button"
          variant="soft"
          size="sm"
          phx-click="print_medium_tracklist"
          phx-value-medium-number={@medium.number}
          phx-target={@myself}
        >
          <span class="sr-only">{gettext("Print tracklist")}</span>
          <.icon name="hero-printer" class="icon" aria-hidden="true" data-slot="icon" />
        </.button>
        <.button
          :if={@can_scrobble?}
          type="button"
          variant="soft"
          size="sm"
          disabled={@already_scrobbled || MapSet.size(@selected_tracks) > 0}
          phx-click="scrobble_medium"
          phx-value-number={@medium.number}
          phx-target={@myself}
          phx-disable-with={gettext("Scrobbling...")}
        >
          <span class="sr-only">{medium_scrobble_label(@medium.format)}</span>
          <.icon name="hero-play" class="icon" aria-hidden="true" data-slot="icon" />
        </.button>
      </.button_group>
    </div>
    <.track_list
      medium_number={@medium.number}
      tracks={@medium.tracks}
      release_artists={@release_artists}
      selected_tracks={@selected_tracks}
      can_scrobble?={@can_scrobble?}
    />
    <.separator />
    <p class="text-right text-xs text-zinc-700 md:text-sm dark:text-zinc-300">
      {medium_duration(@medium)}
    </p>
    """
  end

  defp medium_scrobble_label(format) do
    if format && String.contains?(format, "Vinyl") do
      gettext("Scrobble side")
    else
      gettext("Scrobble disc")
    end
  end

  attr :medium_number, :integer, required: true
  attr :tracks, :list, required: true
  attr :release_artists, :list, required: true
  attr :selected_tracks, :any, required: true
  attr :can_scrobble?, :boolean, required: true

  def track_list(assigns) do
    ~H"""
    <ul id={"disc-#{@medium_number}"} class="table w-full table-auto">
      <li
        :for={track <- @tracks}
        class="list-none leading-5 text-zinc-700 dark:text-zinc-300 md:mt-4"
      >
        <label class="contents cursor-pointer">
          <div class="table-row">
            <span :if={@can_scrobble?} class="table-cell pr-2 align-middle">
              <input
                type="checkbox"
                id={"track-checkbox-#{track.id}"}
                name="release[selected_tracks][]"
                value={track.id}
                checked={MapSet.member?(@selected_tracks, track.id)}
                class="size-4 rounded border-gray-300 bg-gray-100 text-blue-600 focus:ring-2 focus:ring-blue-500 dark:border-gray-600 dark:bg-gray-700 dark:ring-offset-gray-800 dark:focus:ring-blue-600"
              />
            </span>
            <span class="table-cell pr-1 text-right text-xs text-nowrap md:text-sm">
              {track.number || track.position}
            </span>
            <span class="table-cell w-full text-xs/8 font-normal md:text-sm">
              {track.title}
            </span>
            <span class="table-cell pl-2 text-right text-xs md:text-sm">
              {track.length && Duration.format_duration(track.length)}
            </span>
          </div>
          <div
            :if={@release_artists !== track.artists}
            class="table-row text-xs md:text-sm"
          >
            <span :if={@can_scrobble?} class="table-cell" />
            <span class="table-cell" />
            <span class="table-cell">
              {Enum.map_join(track.artists, ", ", fn artist -> artist.name end)}
            </span>
          </div>
        </label>
      </li>
    </ul>
    """
  end

  defguardp release_loaded?(assigns) when assigns.release_with_tracks.ok?

  @impl true
  def handle_event("scrobble_release", _params, socket) when release_loaded?(socket.assigns) do
    release_with_tracks = socket.assigns.release_with_tracks.result

    case ScrobbleActivity.scrobble_release(release_with_tracks, :finished_at, DateTime.utc_now()) do
      {:ok, _} ->
        send_update_after(socket.assigns.myself, %{already_scrobbled: false}, 3000)
        put_toast!(:info, gettext("Release scrobbled successfully"))

        {:noreply, socket |> assign(:already_scrobbled, true)}

      {:error, reason} ->
        Logger.error("Error scrobbling release: #{inspect(reason)}")

        put_toast!(
          :error,
          gettext("Error scrobbling release") <> ": " <> ErrorMessages.friendly_message(reason)
        )

        {:noreply, socket}
    end
  end

  def handle_event("scrobble_release", _params, socket) do
    put_toast!(:error, gettext("Error scrobbling release"))
    {:noreply, socket}
  end

  def handle_event("scrobble_medium", %{"number" => number}, socket)
      when release_loaded?(socket.assigns) do
    release_with_tracks = socket.assigns.release_with_tracks.result
    {number, ""} = Integer.parse(number)

    case ScrobbleActivity.scrobble_medium(
           number,
           release_with_tracks,
           :finished_at,
           DateTime.utc_now()
         ) do
      {:ok, _} ->
        send_update_after(socket.assigns.myself, %{already_scrobbled: false}, 3000)
        put_toast!(:info, gettext("Disc scrobbled successfully"))

        {:noreply, socket |> assign(:already_scrobbled, true)}

      {:error, reason} ->
        Logger.error("Error scrobbling medium: #{inspect(reason)}")

        put_toast!(
          :error,
          gettext("Error scrobbling disc") <> ": " <> ErrorMessages.friendly_message(reason)
        )

        {:noreply, socket}
    end
  end

  def handle_event("scrobble_medium", _params, socket) do
    put_toast!(:error, gettext("Error scrobbling disc"))
    {:noreply, socket}
  end

  def handle_event("validate", %{"release" => params}, socket)
      when release_loaded?(socket.assigns) do
    release = socket.assigns.release_with_tracks.result
    new_selected = apply_form_params(release, params, socket.assigns.selected_tracks)
    {:noreply, assign(socket, :selected_tracks, new_selected)}
  end

  def handle_event("validate", %{"release" => params}, socket) do
    # Release not yet loaded (e.g., phx-auto-recover fires before async completes).
    # Stash the params; handle_async/3 will apply them once the release is available.
    {:noreply, assign(socket, :pending_form_params, params)}
  end

  def handle_event("validate", _params, socket) do
    {:noreply, socket}
  end

  def handle_event("recover_form", params, socket) do
    handle_event("validate", params, socket)
  end

  def handle_event("scrobble_selected_tracks", _params, socket)
      when release_loaded?(socket.assigns) do
    release_with_tracks = socket.assigns.release_with_tracks.result
    selected_track_ids = socket.assigns.selected_tracks

    if MapSet.size(selected_track_ids) == 0 do
      put_toast!(:error, gettext("No tracks selected"))
      {:noreply, socket}
    else
      case ScrobbleActivity.scrobble_tracks(
             selected_track_ids,
             release_with_tracks,
             :finished_at,
             DateTime.utc_now()
           ) do
        {:ok, _} ->
          send_update_after(socket.assigns.myself, %{already_scrobbled: false}, 3000)
          put_toast!(:info, gettext("Selected tracks scrobbled successfully"))

          {:noreply,
           socket
           |> assign(:already_scrobbled, true)
           |> assign(:selected_tracks, MapSet.new())}

        {:error, reason} ->
          Logger.error("Error scrobbling tracks: #{inspect(reason)}")

          put_toast!(
            :error,
            gettext("Error scrobbling selected tracks") <>
              ": " <> ErrorMessages.friendly_message(reason)
          )

          {:noreply, socket}
      end
    end
  end

  def handle_event("scrobble_selected_tracks", _params, socket) do
    put_toast!(:error, gettext("Error scrobbling selected tracks"))
    {:noreply, socket}
  end

  def handle_event("print_tracklist", _params, socket) when release_loaded?(socket.assigns) do
    release = socket.assigns.release_with_tracks.result
    record = socket.assigns.record

    case TracklistPdf.generate(record, release) do
      {:ok, pdf_binary} ->
        filename = "#{record.title} - Tracklist.pdf"

        {:noreply,
         push_event(socket, "music_library:download", %{
           data: Base.encode64(pdf_binary),
           filename: filename,
           content_type: "application/pdf"
         })}

      {:error, reason} ->
        Logger.error("Error generating tracklist PDF: #{inspect(reason)}")

        put_toast!(
          :error,
          gettext("Error generating tracklist PDF") <>
            ": " <> ErrorMessages.friendly_message(reason)
        )

        {:noreply, socket}
    end
  end

  def handle_event("print_tracklist", _params, socket) do
    {:noreply, socket}
  end

  def handle_event("print_medium_tracklist", %{"medium-number" => number}, socket)
      when release_loaded?(socket.assigns) do
    release = socket.assigns.release_with_tracks.result
    record = socket.assigns.record
    {number, ""} = Integer.parse(number)

    case TracklistPdf.generate_medium(record, release, number) do
      {:ok, pdf_binary} ->
        filename = "#{record.title} - Disc #{number} - Tracklist.pdf"

        {:noreply,
         push_event(socket, "music_library:download", %{
           data: Base.encode64(pdf_binary),
           filename: filename,
           content_type: "application/pdf"
         })}

      {:error, reason} ->
        Logger.error("Error generating medium tracklist PDF: #{inspect(reason)}")

        put_toast!(
          :error,
          gettext("Error generating tracklist PDF") <>
            ": " <> ErrorMessages.friendly_message(reason)
        )

        {:noreply, socket}
    end
  end

  def handle_event("print_medium_tracklist", _params, socket) do
    {:noreply, socket}
  end

  def handle_event("load_release_tracks", _params, socket) do
    selected_release_id = socket.assigns.record.selected_release_id

    {:noreply,
     socket
     |> assign(:release_with_tracks, AsyncResult.loading())
     |> start_async(:release_with_tracks, fn ->
       load_release_with_tracks(selected_release_id)
     end)}
  end

  defp load_release_with_tracks(release_id) do
    with {:ok, release} <- MusicBrainz.get_release(release_id) do
      {:ok, MusicBrainz.Release.from_api_response(release)}
    end
  end

  defp medium_selected?(medium, selected_tracks) do
    medium_track_ids = medium.tracks |> Enum.map(& &1.id) |> MapSet.new()
    MapSet.subset?(medium_track_ids, selected_tracks)
  end

  @doc """
  Applies form params from a track-selection form to produce a new `selected_tracks` MapSet.

  Detects master-toggle transitions (the `release[toggle_medium][]` field) by diffing the
  incoming params against the current server-side `current_selected` MapSet. When a medium's
  master toggle transitions from unchecked to checked, all of its tracks are added; when it
  transitions the other way, all of its tracks are removed.

  Used by both `Release` (as a LiveComponent) and `MusicLibraryWeb.ScrobbleLive.Show` to
  share identical form-driven selection logic.
  """
  @spec apply_form_params(MusicBrainz.Release.t(), map(), MapSet.t()) :: MapSet.t()
  def apply_form_params(release, params, current_selected) do
    form_selected =
      (params["selected_tracks"] || [])
      |> Enum.reject(&(&1 == ""))
      |> MapSet.new()

    toggled_medium_numbers =
      (params["toggle_medium"] || [])
      |> Enum.reject(&(&1 == ""))
      |> Enum.map(&String.to_integer/1)
      |> MapSet.new()

    current_fully_selected =
      for medium <- release.media,
          medium_selected?(medium, current_selected),
          into: MapSet.new(),
          do: medium.number

    Enum.reduce(release.media, form_selected, fn medium, acc ->
      was_fully_selected? = MapSet.member?(current_fully_selected, medium.number)
      is_toggled_now? = MapSet.member?(toggled_medium_numbers, medium.number)
      medium_track_ids = medium.tracks |> Enum.map(& &1.id) |> MapSet.new()

      cond do
        not was_fully_selected? and is_toggled_now? ->
          MapSet.union(acc, medium_track_ids)

        was_fully_selected? and not is_toggled_now? ->
          MapSet.difference(acc, medium_track_ids)

        true ->
          acc
      end
    end)
  end

  def scrobble_button_label(selected_tracks) do
    if MapSet.size(selected_tracks) > 0 do
      gettext("Scrobble selected tracks")
    else
      gettext("Scrobble release")
    end
  end

  defp medium_duration(medium) do
    medium
    |> MusicBrainz.Release.medium_duration()
    |> Duration.format_duration()
  end

  defp medium_title(medium) do
    if medium.title === "" do
      gettext("Disc %{no}", %{no: medium.number})
    else
      medium.title
    end
  end
end