class Groups::MilestonesController < Groups::ApplicationController
  include MilestoneActions

  before_action :group_projects
  before_action :milestone, only: [:show, :update, :merge_requests, :participants, :labels]
  before_action :authorize_admin_milestones!, only: [:new, :create, :update]

  def index
    respond_to do |format|
      format.html do
        @milestone_states = GlobalMilestone.states_count(@projects)
        @milestones = Kaminari.paginate_array(milestones).page(params[:page])
      end
      format.json do
        render json: milestones.map { |m| m.for_display.slice(:title, :name) }
      end
    end
  end

  def new
    @milestone = Milestone.new
  end

  def create
    project_ids = params[:milestone][:project_ids].reject(&:blank?)
    title = milestone_params[:title]

    if create_milestones(project_ids)
      redirect_to milestone_path(title)
    else
      render_new_with_error(project_ids.empty?)
    end
  end

  def show
  end

  def update
    @milestone.milestones.each do |milestone|
      Milestones::UpdateService.new(milestone.project, current_user, milestone_params).execute(milestone)
    end

    redirect_back_or_default(default: milestone_path(@milestone.title))
  end

  private

  def create_milestones(project_ids)
    return false unless project_ids.present?

    ActiveRecord::Base.transaction do
      @projects.where(id: project_ids).each do |project|
        Milestones::CreateService.new(project, current_user, milestone_params).execute
      end
    end

    true
  rescue ActiveRecord::ActiveRecordError => e
    flash.now[:alert] = "An error occurred while creating the milestone: #{e.message}"
    false
  end

  def render_new_with_error(empty_project_ids)
    @milestone = Milestone.new(milestone_params)
    @milestone.errors.add(:base, "Please select at least one project.") if empty_project_ids
    render :new
  end

  def authorize_admin_milestones!
    return render_404 unless can?(current_user, :admin_milestones, group)
  end

  def milestone_params
    params.require(:milestone).permit(:title, :description, :start_date, :due_date, :state_event)
  end

  def milestone_path(title)
    group_milestone_path(@group, title.to_slug.to_s, title: title)
  end

  def milestones
    @milestones = GroupMilestone.build_collection(@group, @projects, params)
  end

  def milestone
    @milestone = GroupMilestone.build(@group, @projects, params[:title])
    render_404 unless @milestone
  end
end
