#!/usr/bin/env ruby
# Copyright (C) 2010 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 'rubygems'
require 'graphviz'
require 'getoptlong'

class Gem2Gv
  def initialize( xGVPath, xUse )
    @oGraph = GraphViz::new( :G, :path => xGVPath, :use => xUse )

    @nodes = []
    @name = 'gem2gv'
  end

  def out( xFormat = "dot", xFile = nil )
    if xFile.nil?
      @oGraph.output( xFormat => String )
    else
      @oGraph.output( xFormat => xFile )
    end
  end

  def go( gemName, version = ">0" )
    nodes = getDependency(gemName, version)

    createEdges( gemName, version, nodes )

    nodes.each do |node|
      unless @nodes.include?(node)
        @nodes << node
        go( node[:name], node[:version] )
      end
    end
  end

  def getDependency( gemName, version = ">0" )
    nodes = []

    dependency = Gem::Dependency.new( gemName, version )
    fetcher = Gem::SpecFetcher.fetcher

    fetcher.find_matching(dependency).each do |spec_tuple, source_uri|
      spec = fetcher.fetch_spec spec_tuple, URI.parse(source_uri)

      spec.dependencies.each do |dep|
        #nodes << { :name => dep.name, :version => dep.version_requirements.to_s} unless nodes.include?({ :name => dep.name, :version => dep.version_requirements.to_s})
        nodes << { :name => dep.name, :version => ">0" } unless nodes.include?({ :name => dep.name, :version => ">0" })
      end
    end

    return nodes
  end

  def getNode( name, version )
    #nodeName = "#{name}#{version}"
    #nodeLabel = "#{name}\n#{version}"
    nodeName = "#{name}"
    nodeLabel = "#{name}"
    return @oGraph.get_node(nodeName) || @oGraph.add_nodes( nodeName, "label" => nodeLabel )
  end

  def createEdges( gemName, version, nodes )
    nodeA = getNode( gemName, version )

    nodes.each do |node|
      nodeB = getNode( node[:name], node[:version] )
      @oGraph.add_edges( nodeA, nodeB )
    end
  end
end

def usage
  puts "usage: gem2gv [-Tformat] [-ofile] [-h] [-V] gemname"
  puts "-T, --output-format format    Output format (default: PNG)"
  puts "-o, --output-file file        Output file (default: STDOUT)"
  puts "-p, --path                    Graphviz path"
  puts "-u, --use PROGRAM             Program to use (default: dot)"
  puts "-s, --stop LIB[,LIB, ...]     Stop on libs"
  puts "-V, --version                 Show version"
  puts "-h, --help                    Show this usage message"
end

def version
  puts "Gem2GraphViz v#{GraphViz::Constants::RGV_VERSION}, (c)2010 Gregoire Lejeune <gregoire.lejeune@free.fr>"
  puts ""
  puts "This program is free software; you can redistribute it and/or modify"
  puts "it under the terms of the GNU General Public License as published by"
  puts "the Free Software Foundation; either version 2 of the License, or"
  puts "(at your option) any later version."
  puts ""
  puts "This program is distributed in the hope that it will be useful,"
  puts "but WITHOUT ANY WARRANTY; without even the implied warranty of"
  puts "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the"
  puts "GNU General Public License for more details."
  puts ""
  puts "You should have received a copy of the GNU General Public License"
  puts "along with this program; if not, write to the Free Software"
  puts "Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA"
end

xOutFormat = "png"
xOutFile = nil
xGVPath = ""
xUse = "dot"

oOpt = GetoptLong.new(
  ['--output-format', '-T', GetoptLong::REQUIRED_ARGUMENT],
  ['--output-file',   '-o', GetoptLong::REQUIRED_ARGUMENT],
  ['--path',          '-p', GetoptLong::REQUIRED_ARGUMENT],
  ['--use',           '-u', GetoptLong::REQUIRED_ARGUMENT],
  ['--help',          '-h', GetoptLong::NO_ARGUMENT],
  ['--version',       '-V', GetoptLong::NO_ARGUMENT]
)

begin
  oOpt.each_option do |xOpt, xValue|
    case xOpt
      when '--output-format'
        xOutFormat = xValue
      when '--output-file'
        xOutFile = xValue
      when '--path'
        xGVPath = xValue
      when '--use'
        xUse = xValue
      when '--help'
        usage( )
        exit
      when '--version'
        version( )
        exit
    end
  end
rescue GetoptLong::InvalidOption
  usage( )
  exit
end

xGem = ARGV[0]

if xGem.nil?
  usage( )
  exit
end


g = Gem2Gv.new( xGVPath, xUse )
g.go( xGem )
result = g.out( xOutFormat, xOutFile )
puts result unless result.nil?