# frozen_string_literal: true

class Api::V1::Timelines::GroupCollectionController < Api::BaseController
  before_action :set_collection_type
  before_action :set_statuses

  after_action :insert_pagination_headers, unless: -> { @statuses.empty? }

  def show
    if current_user
      render json: @statuses,
        each_serializer: REST::StatusSerializer,
        relationships: StatusRelationshipsPresenter.new(@statuses, current_user.account_id)
    else
      render json: @statuses, each_serializer: REST::StatusSerializer
    end
  end

  def set_collection_type
    @collection_type = nil
    @collection_type = params[:id] if ['featured', 'member'].include? params[:id]

    if @collection_type.nil?
      return render json: { error: 'Invalid collection type' }, status: 422
    end

    return @collection_type
  end

  private

  def set_statuses
    @statuses = cached_group_collection_statuses
  end

  def cached_group_collection_statuses
    cache_collection group_collection_statuses, Status
  end

  def group_collection_statuses
    statuses = nil

    @groupIds = []
    if @collection_type == 'featured'
      @groupIds = Group.where(is_featured: true, is_archived: false).limit(100).all.pluck(:id)
    elsif @collection_type == 'member'
      @groupIds = current_user.account.groups.pluck(:id)
    end

    if current_account
      statuses = Status.as_group_collection_timeline(@groupIds).paginate_by_id(
        limit_param(DEFAULT_STATUSES_LIMIT),
        params_slice(:max_id, :since_id, :min_id)
      ).reject { |status| FeedManager.instance.filter?(:home, status, current_account.id) }
    else
      statuses = Status.as_group_collection_timeline(@groupIds).paginate_by_id(
        limit_param(DEFAULT_STATUSES_LIMIT),
        params_slice(:max_id, :since_id, :min_id)
      )
    end

    if truthy_param?(:only_media) && current_account
      # `SELECT DISTINCT id, updated_at` is too slow, so pluck ids at first, and then select id, updated_at with ids.
      status_ids = statuses.joins(:media_attachments).distinct(:id).pluck(:id)
      statuses.where(id: status_ids)
    else
      statuses
    end
  end

  def insert_pagination_headers
    set_pagination_headers(next_path, prev_path)
  end

  def pagination_params(core_params)
    params.slice(:limit).permit(:limit).merge(core_params)
  end

  def next_path
    api_v1_timelines_group_collection_url pagination_params(max_id: pagination_max_id)
  end

  def prev_path
    api_v1_timelines_group_collection_url pagination_params(min_id: pagination_since_id)
  end

  def pagination_max_id
    @statuses.last.id
  end

  def pagination_since_id
    @statuses.first.id
  end

end