# frozen_string_literal: true

module ActionController
  module Rendering
    extend ActiveSupport::Concern

    RENDER_FORMATS_IN_PRIORITY = [:body, :plain, :html]

    module ClassMethods
      # Documentation at ActionController::Renderer#render
      delegate :render, to: :renderer

      # Returns a renderer instance (inherited from ActionController::Renderer)
      # for the controller.
      attr_reader :renderer

      def setup_renderer! # :nodoc:
        @renderer = Renderer.for(self)
      end

      def inherited(klass)
        klass.setup_renderer!
        super
      end
    end

    # Renders a template and assigns the result to +self.response_body+.
    #
    # If no rendering mode option is specified, the template will be derived
    # from the first argument.
    #
    #   render "posts/show"
    #   # => renders app/views/posts/show.html.erb
    #
    #   # In a PostsController action...
    #   render :show
    #   # => renders app/views/posts/show.html.erb
    #
    # If the first argument responds to +render_in+, the template will be
    # rendered by calling +render_in+ with the current view context.
    #
    # ==== \Rendering Mode
    #
    # [+:partial+]
    #   See ActionView::PartialRenderer for details.
    #
    #     render partial: "posts/form", locals: { post: Post.new }
    #     # => renders app/views/posts/_form.html.erb
    #
    # [+:file+]
    #   Renders the contents of a file. This option should <b>not</b> be used
    #   with unsanitized user input.
    #
    #     render file: "/path/to/some/file"
    #     # => renders /path/to/some/file
    #
    # [+:inline+]
    #   Renders an ERB template string.
    #
    #     @name = "World"
    #     render inline: "<h1>Hello, <%= @name %>!</h1>"
    #     # => renders "<h1>Hello, World!</h1>"
    #
    # [+:body+]
    #   Renders the provided text, and sets the content type as +text/plain+.
    #
    #     render body: "Hello, World!"
    #     # => renders "Hello, World!"
    #
    # [+:plain+]
    #   Renders the provided text, and sets the content type as +text/plain+.
    #
    #     render plain: "Hello, World!"
    #     # => renders "Hello, World!"
    #
    # [+:html+]
    #   Renders the provided HTML string, and sets the content type as +text/html+.
    #   If the string is not +html_safe?+, performs HTML escaping on the string
    #   before rendering.
    #
    #     render html: "<h1>Hello, World!</h1>".html_safe
    #     # => renders "<h1>Hello, World!</h1>"
    #
    #     render html: "<h1>Hello, World!</h1>"
    #     # => renders "&lt;h1&gt;Hello, World!&lt;/h1&gt;"
    #
    # [+:json+]
    #   Renders the provided object as JSON, and sets the content type as
    #   +application/json+. If the object is not a string, it will be converted
    #   to JSON by calling +to_json+.
    #
    #     render json: { hello: "world" }
    #     # => renders "{\"hello\":\"world\"}"
    #
    # By default, when a rendering mode is specified, no layout template is
    # rendered.
    #
    # ==== Options
    #
    # [+:assigns+]
    #   Hash of instance variable assignments for the template.
    #
    #     render inline: "<h1>Hello, <%= @name %>!</h1>", assigns: { name: "World" }
    #     # => renders "<h1>Hello, World!</h1>"
    #
    # [+:locals+]
    #   Hash of local variable assignments for the template.
    #
    #     render inline: "<h1>Hello, <%= name %>!</h1>", locals: { name: "World" }
    #     # => renders "<h1>Hello, World!</h1>"
    #
    # [+:layout+]
    #   The layout template to render. Can also be +false+ or +true+ to disable
    #   or (re)enable the default layout template.
    #
    #     render "posts/show", layout: "holiday"
    #     # => renders app/views/posts/show.html.erb with the app/views/layouts/holiday.html.erb layout
    #
    #     render "posts/show", layout: false
    #     # => renders app/views/posts/show.html.erb with no layout
    #
    #     render inline: "<h1>Hello, World!</h1>", layout: true
    #     # => renders "<h1>Hello, World!</h1>" with the default layout
    #
    # [+:status+]
    #   The HTTP status code to send with the response. Can be specified as a
    #   number or as the status name in Symbol form. Defaults to 200.
    #
    #     render "posts/new", status: 422
    #     # => renders app/views/posts/new.html.erb with HTTP status code 422
    #
    #     render "posts/new", status: :unprocessable_entity
    #     # => renders app/views/posts/new.html.erb with HTTP status code 422
    #
    #--
    # Check for double render errors and set the content_type after rendering.
    def render(*args)
      raise ::AbstractController::DoubleRenderError if response_body
      super
    end

    # Similar to #render, but only returns the rendered template as a string,
    # instead of setting +self.response_body+.
    #--
    # Override render_to_string because body can now be set to a Rack body.
    def render_to_string(*)
      result = super
      if result.respond_to?(:each)
        string = +""
        result.each { |r| string << r }
        string
      else
        result
      end
    end

    def render_to_body(options = {}) # :nodoc:
      super || _render_in_priorities(options) || " "
    end

    private
      # Before processing, set the request formats in current controller formats.
      def process_action(*) # :nodoc:
        self.formats = request.formats.filter_map(&:ref)
        super
      end

      def _process_variant(options)
        if defined?(request) && !request.nil? && request.variant.present?
          options[:variant] = request.variant
        end
      end

      def _render_in_priorities(options)
        RENDER_FORMATS_IN_PRIORITY.each do |format|
          return options[format] if options.key?(format)
        end

        nil
      end

      def _set_html_content_type
        self.content_type = Mime[:html].to_s
      end

      def _set_rendered_content_type(format)
        if format && !response.media_type
          self.content_type = format.to_s
        end
      end

      def _set_vary_header
        if response.headers["Vary"].blank? && request.should_apply_vary_header?
          response.headers["Vary"] = "Accept"
        end
      end

      # Normalize both text and status options.
      def _normalize_options(options)
        _normalize_text(options)

        if options[:html]
          options[:html] = ERB::Util.html_escape(options[:html])
        end

        if options[:status]
          options[:status] = Rack::Utils.status_code(options[:status])
        end

        super
      end

      def _normalize_text(options)
        RENDER_FORMATS_IN_PRIORITY.each do |format|
          if options.key?(format) && options[format].respond_to?(:to_text)
            options[format] = options[format].to_text
          end
        end
      end

      # Process controller specific options, as status, content-type and location.
      def _process_options(options)
        status, content_type, location = options.values_at(:status, :content_type, :location)

        self.status = status if status
        self.content_type = content_type if content_type
        headers["Location"] = url_for(location) if location

        super
      end
  end
end
