module ActiveAdmin
  module Views

    # # Index as Blog
    #
    # Render your index page as a set of posts. The post has two main options:
    # title and body.
    #
    # ```ruby
    # index as: :blog do
    #   title :my_title # Calls #my_title on each resource
    #   body  :my_body  # Calls #my_body on each resource
    # end
    # ```
    #
    # ## Post Title
    #
    # The title is the content that will be rendered within a link to the
    # resource. There are two main ways to set the content for the title
    #
    # First, you can pass in a method to be called on your resource. For example:
    #
    # ```ruby
    # index as: :blog do
    #   title :a_method_to_call
    # end
    # ```
    #
    # Second, you can pass a block to the tile option which will then be
    # used as the contents of the title. The resource being rendered
    # is passed in to the block. For Example:
    #
    # ```ruby
    # index as: :blog do
    #   title do |post|
    #     span post.title,      class: 'title'
    #     span post.created_at, class: 'created_at'
    #   end
    # end
    # ```
    #
    # ## Post Body
    #
    # The body is rendered underneath the title of each post. The same two
    # style of options work as the Post Title above.
    #
    # Call a method on the resource as the body:
    #
    # ```ruby
    # index as: :blog do
    #   title :my_title
    #   body :my_body
    # end
    # ```
    #
    # Or, render a block as the body:
    #
    # ```ruby
    # index as: :blog do
    #   title :my_title
    #   body do |post|
    #     div truncate post.title
    #     div class: 'meta' do
    #       span "Post in #{post.categories.join(', ')}"
    #     end
    #   end
    # end
    # ```
    #
    class IndexAsBlog < ActiveAdmin::Component

      def build(page_presenter, collection)
        @page_presenter = page_presenter
        @collection = collection

        # Call the block passed in. This will set the
        # title and body methods
        instance_exec &page_presenter.block if page_presenter.block

        add_class "index"
        build_posts
      end

      # Setter method for the configuration of the title
      def title(method = nil, &block)
        if block_given? || method
          @title = block_given? ? block : method
        end
        @title
      end

      # Setter method for the configuration of the body
      #
      def body(method = nil, &block)
        if block_given? || method
          @body = block_given? ? block : method
        end
        @body
      end

      def self.index_name
        "blog"
      end

      private

      def build_posts
        resource_selection_toggle_panel if active_admin_config.batch_actions.any?
        @collection.each do |post|
          build_post(post)
        end
      end

      def build_post(post)
        div for: post do
          resource_selection_cell(post) if active_admin_config.batch_actions.any?
          build_title(post)
          build_body(post)
        end
      end

      def build_title(post)
        if @title
          h3 do
            a(href: resource_path(post)) do
              render_method_on_post_or_call_proc post, @title
            end
          end
        else
          h3 do
            auto_link(post)
          end
        end
      end

      def build_body(post)
        if @body
          div class: 'content' do
            render_method_on_post_or_call_proc post, @body
          end
        end
      end

      def render_method_on_post_or_call_proc(post, proc)
        case proc
        when String, Symbol
          post.public_send proc
        else
          instance_exec post, &proc
        end
      end

    end # Posts
  end
end