# Copyright (C) 2004 - 2012 Gregoire Lejeune <gregoire.lejeune@free.fr>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA

require 'graphviz/attrs'
require 'graphviz/constants'

class GraphViz
   class Edge
      include Constants

      # Create a new edge
      #
      # In:
      # * vNodeOne : First node (can be a GraphViz::Node or a node ID)
      # * vNodeTwo : Second node (can be a GraphViz::Node or a node ID)
      # * parent_graph : Graph
      def initialize( vNodeOne, vNodeTwo, parent_graph )
         @node_one_id, @node_one_port = getNodeNameAndPort( vNodeOne )
         @node_two_id, @node_two_port = getNodeNameAndPort( vNodeTwo )

         @parent_graph = parent_graph
         @edge_attributes = GraphViz::Attrs::new( nil, "edge", EDGESATTRS )
         @index = nil

         unless @parent_graph.directed?
            (@parent_graph.find_node(@node_one_id) || @parent_graph.add_nodes(@node_one_id)).incidents << (@parent_graph.find_node(@node_two_id) || @parent_graph.add_nodes(@node_two_id))
            (@parent_graph.find_node(@node_two_id) || @parent_graph.add_nodes(@node_two_id)).neighbors << (@parent_graph.find_node(@node_one_id) || @parent_graph.add_nodes(@node_one_id))
         end
         (@parent_graph.find_node(@node_one_id) || @parent_graph.add_nodes(@node_one_id)).neighbors << (@parent_graph.find_node(@node_two_id) || @parent_graph.add_nodes(@node_two_id))
         (@parent_graph.find_node(@node_two_id) || @parent_graph.add_nodes(@node_two_id)).incidents << (@parent_graph.find_node(@node_one_id) || @parent_graph.add_nodes(@node_one_id))
      end

      # Return the node one as string (so with port if any)
      def node_one( with_port = true )
         if not (@node_one_port and with_port)
            GraphViz.escape(@node_one_id)
         else
            GraphViz.escape(@node_one_id, :force => true) + ":#{@node_one_port}"
         end
      end
      alias :tail_node :node_one

      # Return the node two as string (so with port if any)
      def node_two( with_port = true )
         if not (@node_two_port and with_port)
            GraphViz.escape(@node_two_id)
         else
            GraphViz.escape(@node_two_id, :force => true) + ":#{@node_two_port}"
         end
      end
      alias :head_node :node_two

      # Return the index of the edge
      def index
         @index
      end
      def index=(i) #:nodoc:
         @index = i if @index == nil
      end

      # Set value +attribute_value+ to the edge attribute +attribute_name+
      def []=( attribute_name, attribute_value )
         attribute_value = attribute_value.to_s if attribute_value.class == Symbol
         @edge_attributes[attribute_name.to_s] = attribute_value
      end

      # Set values for edge attributes or
      # get the value of the given edge attribute +attribute_name+
      def []( attribute_name )
         # Modification by axgle (http://github.com/axgle)
         if Hash === attribute_name
            attribute_name.each do |key, value|
               self[key] = value
            end
         else
            if @edge_attributes[attribute_name.to_s]
               @edge_attributes[attribute_name.to_s].clone
            else
               nil
            end
         end
      end

      #
      # Calls block once for each attribute of the edge, passing the name and value to the
      # block as a two-element array.
      #
      # If global is set to false, the block does not receive the attributes set globally
      #
      def each_attribute(global = true, &b)
         attrs = @edge_attributes.to_h
         if global
            attrs = pg.edge.to_h.merge attrs
         end
         attrs.each do |k,v|
            yield(k,v)
         end
      end
      def each_attribut(global = true, &b)
         warn "`GraphViz::Edge#each_attribut` is deprecated, please use `GraphViz::Edge#each_attribute`"
         each_attribute(global, &b)
      end

      def <<( node ) #:nodoc:
         n = @parent_graph.get_node(@node_two_id)

         GraphViz::commonGraph( node, n ).add_edges( n, node )
      end
      alias :> :<< #:nodoc:
      alias :- :<< #:nodoc:
      alias :>> :<< #:nodoc:

      #
      # Return the root graph
      #
      def root_graph
         return( (self.pg.nil?) ? nil : self.pg.root_graph )
      end

      def pg #:nodoc:
         @parent_graph
      end

      # Set edge attributes
      #
      # Example :
      #   e = graph.add_edges( ... )
      #   ...
      #   e.set { |_e|
      #     _e.color = "blue"
      #     _e.fontcolor = "red"
      #   }
      def set( &b )
         yield( self )
      end

      # Add edge options
      # use edge.<option>=<value> or edge.<option>( <value> )
      def method_missing( idName, *args, &block ) #:nodoc:
         return if idName == :to_ary # ruby 1.9.2 fix
         xName = idName.id2name

         self[xName.gsub( /=$/, "" )]=args[0]
      end

      def output( oGraphType ) #:nodoc:
         xLink = " -> "
         if oGraphType == "graph"
            xLink = " -- "
         end

         xOut = self.node_one + xLink + self.node_two
         xAttr = ""
         xSeparator = ""
         @edge_attributes.data.each do |k, v|
            xAttr << xSeparator + k + " = " + v.to_gv
            xSeparator = ", "
         end
         if xAttr.length > 0
            xOut << " [" + xAttr + "]"
         end
         xOut + ";"

         return( xOut )
      end

      private
      def getNodeNameAndPort( node )
         name, port = nil, nil
         if node.class == Hash
            node.each do |k, v|
               name, port = getNodeNameAndPort(k)
               port = v
            end
         elsif node.class == String
            name = node
         else
            name = node.id
         end

         return name, port
      end
   end
end