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

    # Create a new link obj
    # @api public
    # @param [Hash] link_data
    # @option link_data [String] url
    # @option link_data [RailsConnector::BasicObj] obj
    # @option link_data [String] title
    # @option link_data [String] query
    # @option link_data [String] target
    # @option link_data [String] fragment
    def initialize(link_data)
      @link_data = link_data.with_indifferent_access
    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

    # Set the link's external url. This will lead to an external link.
    # @api public
    # @param value [String] the url of the link
    def url=(value)
      @link_data[:url] = value
    end

    # Returns the (+Obj+) this link is referencing. May be nil if the
    # link is external.
    # @api public
    def obj
      @link_data[:obj]
    end

    # Set the (+Obj+) this link is referencing. May be nil if the
    # link is external.
    # @api public
    # @param value [RailsConnector::BasicObj] the obj this link should be referencing
    def obj=(value)
      @link_data[:obj] = value
    end

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

    # Set the link's title.
    # @api public
    # @param value [String] the link's title
    def title=(value)
      @link_data[:title] = value
    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

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

    # Set the link's anchor as in "index.html#anchor".
    # See RFC3986 for details (http://www.ietf.org/rfc/rfc3986.txt).
    # @api public
    # @param value [String] the anchor or fragement of the link
    def fragment=(value)
      @link_data[:fragment] = value
    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

    # Set 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
    # @param value [String] the target of the link
    def target=(value)
      @link_data[:target] = value
    end

    def id
      @link_data[:link_id]
    end

    def tag_name
      @link_data[:tag_name]
    end

    def tag_name=(value)
      @link_data[:tag_name] = value
    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?
        obj ? obj.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
    # @deprecated use {#obj}.id instead
    def destination_object_id
      deprecation_warning(:destination_object_id, 'obj.id')
      obj.id
    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 = obj.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? || (obj && obj.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
    # @deprecated use {#obj} instead
    def destination_object
      deprecation_warning(:destination_object, :obj)
      obj
    end

    def html_attribute_snippet
      parts = []
      parts << %{alt="#{title}"} if tag_name == 'img' || tag_name == 'input'
      parts << %{title="#{title}"} if (tag_name == 'a' || tag_name == 'link') && title.present?
      parts << %{target="#{target}"} if target.present?
      parts.join(' ')
    end

    def query_and_fragment
      str = ''
      str << "?#{query}" if query.present?
      str << "##{fragment}" if fragment.present?
      str
    end

    def internal_url
      "objid:#{obj.id}"
    end

    def external_url
      external_prefix? ? url.gsub(/external:/, '').strip : url
    end

    private

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

    def deprecation_warning(method, alternative)
      ActiveSupport::Deprecation.warn(
        "[DEPRECATION] The medod #{method} will be removed from the RailsConnector. Please use #{alternative} instead"
      )
    end

  end
end