module Api
  # Server documents. Listing and creating need an account; reading and
  # writing a single document also work with just a share link token.
  class DocumentsController < BaseController
    before_action :require_authentication, only: %i[index create]
    before_action :load_document, except: %i[index create]

    # GET /api/documents -- owned + shared with me
    def index
      user = Current.user
      memberships = user.document_memberships.index_by(&:document_id)
      docs = user.accessible_documents.includes(:owner, :updated_by).order(content_updated_at: :desc)
      render json: {
        documents: docs.map { |d| d.meta_json(role: d.owner_id == user.id ? :owner : memberships[d.id]&.role) }
      }
    end

    # POST /api/documents { title, content } -- also used to upload a local document
    def create
      doc = Current.user.owned_documents.create!(
        title: params.require(:title), content: content_param, updated_by: Current.user
      )
      render json: { document: doc.meta_json(role: :owner) }, status: :created
    end

    # GET /api/documents/:id[?content=0]
    # The content is the JSON snapshot the editors keep current (the live
    # content comes through DocumentChannel).
    def show
      touch_membership
      meta = @doc.meta_json(role: @role)
      meta[:content] = @doc.content unless params[:content] == "0"
      render json: { document: meta }
    end

    # PATCH /api/documents/:id { title }
    def update
      return forbidden unless Document.role_at_least?(@role, :editor)
      @doc.update!(title: params.require(:title))
      @doc.broadcast({ type: "meta", title: @doc.title })
      render json: { document: @doc.meta_json(role: @role) }
    end

    # DELETE /api/documents/:id -- the owner deletes it; anyone else leaves it
    def destroy
      if @role == :owner
        @doc.destroy!
        @doc.broadcast({ type: "revoked" })
      elsif Current.user
        @doc.document_memberships.where(user: Current.user).delete_all
        @doc.revalidate_access!
      else
        return forbidden
      end
      head :no_content
    end

    private

    def load_document
      @doc = Document.find(params[:id])
      @role = @doc.role_for(user: Current.user, token: share_token)
      raise ActiveRecord::RecordNotFound unless @role # 404, not 403: don't confirm it exists
    end

    def content_param
      c = params.require(:content)
      c.is_a?(String) ? c : c.to_unsafe_h.to_json
    end

    def touch_membership
      return unless Current.user
      @doc.document_memberships.where(user: Current.user).update_all(last_opened_at: Time.current)
    end

    def forbidden = render(json: { error: "forbidden" }, status: :forbidden)
  end
end