module RailsConnector
  # This class provides an interfaces for handling CMS Links.
  # To format a link for rendering in an html page, use the +cms_path+ or +cms_url+ methods.
  # @api public
  class Link

    extend ActiveModel::Naming

    def initialize(link_data, destination_object = nil)
      @link_data = link_data.symbolize_keys
      @destination_object = destination_object
    end

    # The link's external url. Only available for external links.
    # Warning: Do not output the url directly unless you know what you are doing.
    # Normally you want to use the +cms_path+ or +cms_url+ methods to format a link.
    # @api public
    def url
      @link_data[:url]
    end

    # The link's title.
    # @api public
    def title
      @link_data[:title]
    end

    # Returns the link's query string as in "index.html?query_string".
    # See RFC3986 for details (http://www.ietf.org/rfc/rfc3986.txt).
    # @api public
    def query
      @link_data[:query]
    end

    # Depricated: use Link#query instead.
    # Returns the link's query string as in "index.html?query_string".
    # See RFC3986 for details (http://www.ietf.org/rfc/rfc3986.txt).
    # @api public
    def search
      query
    end

    # Returns the link's anchor as in "index.html#anchor".
    # See RFC3986 for details (http://www.ietf.org/rfc/rfc3986.txt).
    # @api public
    def fragment
      @link_data[:fragment]
    end

    # Returns the browser window or browser frame to be used as a target for this link.
    # Example: Links that should be opened in a new window will return "_blank" as their target.
    # @api public
    def target
      @link_data[:target]
    end

    def id
      @link_data[:link_id]
    end

    def tag_name
      @link_data[:tag_name]
    end

    def markdown_type
      @link_data[:markdown_type]
    end

    def markdown?
      'markdown' == @link_data[:source_format]
    end

    # Returns the file extension (e.g. zip, pdf) of this link's (internal or external) target.
    # Returns an empty string if the file extension is can not be determined.
    # @api public
    def file_extension
      if internal?
        destination_object ? destination_object.file_extension : ""
      else
        path = URI.parse(url).path rescue nil
        path.blank? ? "" : File.extname(path)[1..-1] || ""
      end
    end

    # Returns the id of the Links' destination_object.
    # @api public
    def destination_object_id
      destination
    end

    # Returns the title of this Link if it is set.
    # Otherwise it returns the display_title of the destination object for internal Links
    # or the URL for external Links.
    # @api public
    def display_title
      dt = title
      dt = destination_object.display_title if dt.blank? && !external?
      dt = url if dt.blank?
      dt
    end

    # Returns true this Link links to a CMS Object.
    # @api public
    def internal?
      url.nil?
    end

    # Returns true if this Link links to an external URL.
    # @api public
    def external?
      !internal?
    end

    # An internal Link is active if it's destination object is active.
    # An external Link is always active.
    # @api public
    def active?
      external? || (destination_object && destination_object.active?)
    end

    def external_prefix?
      nil != (url =~ /\s?external:/)
    end

    def resolved?
      external? || resolved_internal?
    end

    # Returns the destination object (+Obj+) of this Link. May be nil if the
    # link is external or internal without an existing destination object.
    # @api public
    def destination_object
      @destination_object ||= Obj.find(destination) if resolved_internal?
    rescue RailsConnector::ResourceNotFound
      nil
    end

    private

    def resolved_internal?
      internal? && !destination.nil?
    end

    def destination
      @link_data[:destination]
    end
  end
end