module Scrivito
  # 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

    # Parses a url and returns a {Link} object. Determines internal urls based on the given
    # +hostname+ and +port+.
    # @api public
    # @param [String] url
    # @param host [String] the hostname of internal urls
    # @param port [String] the port of internal urls
    def self.parse(url, host, port)
      LinkParser.new(host, port).parse(url)
    end

    # Create a new link obj
    # @api public
    # @param [Hash] link_data
    # @option link_data [String] url
    # @option link_data [Obj] 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 {BasicObj Obj} this link is referencing. May be nil if the
    # link is external.
    # @api public
    def obj
      @link_data[:obj]
    end

    # Set the {BasicObj Obj} this link is referencing. May be nil if the
    # link is external.
    # @api public
    # @param value [Obj] 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

    def target
      @link_data[:target]
    end

    def target=(value)
      @link_data[:target] = 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 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

    def resolved?
      external? || !obj.nil?
    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 to_cms_api_html_url
      if internal?
        "#{internal_url}#{query_and_fragment}"
      else
        url
      end
    end

    def to_cms_api_linklist_params
      params = {}

      if internal?
        params[:obj_id] = obj.id
        params[:title] = title if title
        params[:query] = query if query
        params[:fragment] = fragment if fragment
      else
        params[:url] = url
        params[:title] = title if title
      end

      params
    end
  end
end