#!/usr/bin/env ruby

# RailRoad - RoR diagrams generator
# http://railroad.rubyforge.org
#
#   RailRoad generates models and controllers diagrams in DOT language
#   for a Rails application.
#
# Copyright 2007 - Javier Smaldone (http://www.smaldone.com.ar)
#
# 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.
#

APP_NAME  = "railroad"
APP_HUMAN_NAME = "RailRoad"
APP_VERSION   = [0,3,0]
COPYRIGHT = "Copyright (C) 2007 Javier Smaldone"


class OptionsParser

  require 'optparse'
  require 'ostruct'

  def self.parse(args)

    options = OpenStruct.new

    options.all = false
    options.brief = false
    options.inheritance = false
    options.join = false
    options.label = false
    options.modules = false
    options.hide_types = false
    options.hide_public = false
    options.hide_protected = false
    options.hide_private = false
    options.command = ''

    opts = OptionParser.new do |opts|
      opts.banner = "Usage: #{APP_NAME} [options] command"
      opts.separator ""
      opts.separator "Common options:"
      opts.on("-b", "--brief", "Generate compact diagram", 
              "  (no attributes nor methods)") do |b|
        options.brief = b
      end
      opts.on("-i", "--inheritance", "Include inheritance relations") do |i|
        options.inheritance = i
      end
      opts.on("-l", "--label", "Add a label with diagram information", 
              "  (type, date, migration, version)") do |l|
        options.label = l
      end
      opts.on("-o", "--output FILE", "Write diagram to file FILE") do |f|
        options.output = f
      end
      opts.separator ""
      opts.separator "Models diagram options:"
      opts.on("-a", "--all", "Include all models", 
              "  (not only ActiveRecord::Base derived)") do |a|
        options.all = a
      end
      opts.on("--hide-types", "Hide attributes type") do |h|
        options.hide_types = h
      end
      opts.on("-j", "--join", "Concentrate edges") do |j|
        options.join = j
      end
      opts.on("-m", "--modules", "Include modules") do |m|
        options.modules = m
      end
      opts.separator ""
      opts.separator "Controllers diagram options:"
      opts.on("--hide-public", "Hide public methods") do |h|
        options.hide_public = h
      end
      opts.on("--hide-protected", "Hide protected methods") do |h|
        options.hide_protected = h
      end
      opts.on("--hide-private", "Hide private methods") do |h|
        options.hide_private = h
      end
      opts.separator ""
      opts.separator "Other options:"
      opts.on("-h", "--help", "Show this message") do
        print "#{opts}\n"
        exit
      end
      opts.on("--version", "Show version and copyright") do
        print "#{APP_HUMAN_NAME} version #{APP_VERSION.join('.')}\n\n" +
              "#{COPYRIGHT}\n" +
              "This is free software; see the source for copying conditions.\n\n"
        exit
      end
      opts.separator ""
      opts.separator "Commands (you must supply one of these):"
      opts.on("-M", "--models", "Generate models diagram") do |c|
         if options.command == 'controllers'
           $stderr.print "Error: Can't generate models AND controllers diagram\n\n"
           exit 1
         else 
           options.command = 'models'        
         end
      end
      opts.on("-C", "--controllers", "Generate controllers diagram") do |c|
         if options.command == 'models'
           $stderr.print "Error: Can't generate models AND controllers diagram\n\n"
           exit 1
         else 
           options.command = 'controllers'        
         end
      end
      opts.separator ""
      opts.separator "For bug reporting instructions and additional information, please see:"
      opts.separator "http://railroad.rubyforge.org"
    end

    begin
      opts.parse!(args)
    rescue OptionParser::AmbiguousOption
      option_error "Ambiguous option", opts 
    rescue OptionParser::InvalidOption
      option_error "Invalid option", opts
    rescue OptionParser::InvalidArgument
      option_error "Invalid argument", opts
    rescue OptionParser::MissingArgument
      option_error "Missing argument", opts
    rescue
      option_error "Unknown error", opts
    end
    options
  end  # self.parse
 
  private 

  def self.option_error(msg, opts)
    $stderr.print "Error: #{msg}\n\n #{opts}\n"
    exit 1
  end

end  # class OptionsParser


class AppDiagram

  def initialize(options)
    @options = options
    load_environment
  end

  private 

  # Quotes a class name
  def node(name)
    '"' + name + '"'
  end

  # Print diagram label
  def print_info(type)
    print "\t_diagram_info [shape=\"plaintext\", label=\"Diagram: #{type}\\l" +
          "Date: #{Time.now.strftime "%b %d %Y - %H:%M"}\\l" + 
          "Migration version: #{ActiveRecord::Migrator.current_version}\\l" +
          "Generated by #{APP_HUMAN_NAME} #{APP_VERSION.join('.')}\\l\""+
          ", fontsize=14]\n"
  end

  def print_error(type)
    STDERR.print "Error loading #{type}.\n  (Are you running " +
                 "#{APP_NAME} on the aplication's root directory?)\n\n"
  end

  # Load Rails application's environment
  def load_environment
    begin
      require "config/environment"
    rescue LoadError
      print_error "app environment"
      raise
    end
  end

end # class AppDiagram


class ModelsDiagram < AppDiagram

  # Generate models diagram
  def generate

    load_classes

    # DOT diagram header
    print "digraph models_diagram {\n" 
    print "\tgraph[concentrate=true]\n" if @options.join
    print_info "Models" if @options.label

    # Processed habtm associations
    @habtm = []

    models_files = Dir.glob("app/models/**/*.rb")
    models_files.each do |m|
      # Extract the class name from the file name
      current_class = m.split('/')[2..-1].join('/').split('.').first.camelize.constantize
      process_class current_class  
    end 
    print "}\n"


  end # generate

  private

  # Load model classes
  def load_classes
    begin
      Dir.glob("app/models/**/*.rb") {|m| require m }
    rescue LoadError
      print_error "model classes"
      raise
    end
  end  # load_classes

  # Process model class
  def process_class(current_class)

    printed = false
    
    # Is current_clas derived from ActiveRecord::Base?
    if current_class.respond_to?'reflect_on_all_associations'

      # Print the node
      if @options.brief
        print "\t#{node(current_class.name)}\n"
      else 
        print "\t#{node(current_class.name)} " +
              "[shape=Mrecord, label=\"{#{current_class.name}|"
        current_class.content_columns.each do |a|
          print "#{a.name}"
          print " :#{a.type.to_s}" unless @options.hide_types
          print "\\l" 
        end
        print "}\"]\n"
      end
      printed = true
      # Iterate over the class associations
      current_class.reflect_on_all_associations.each { |a|
        process_association(current_class, a)
      }
    elsif @options.all && (current_class.is_a? Class)
      # Not ActiveRecord::Base model
      if @options.brief
        print "\t#{node(current_class.name)} [shape=box]\n"
      else 
        print "\t#{node(current_class.name)}" +
              "[shape=record, label=\"{#{current_class.name}|}\"]\n"
      end
      printed = true
    elsif @options.modules && (current_class.is_a? Module)
        print "\t#{node(current_class.name)}" +
              "[shape=box, style=dotted, label=\"#{current_class.name}\"]\n"      
    end

    # Only consider meaningful inheritance relations for printed classes
    if @options.inheritance && printed && 
       (current_class.superclass != ActiveRecord::Base) &&
       (current_class.superclass != Object)
      print "\t\t#{node(current_class.name)} -> " +
            "#{node(current_class.superclass.name)}" +
            " [arrowhead=\"onormal\"]\n"
    end      

  end # process_class

  # Process model association
  def process_association(current_class, association)

    # Only non standard association names needs a label
    if association.class_name != association.name.to_s.singularize.camelize
      params = "label=\"#{association.name.to_s}\", "
    else
      params = ""
    end

    # Skip "belongs_to" associations
    if association.macro.to_s != 'belongs_to'
      # Put a tail label with the association arity
      if association.macro.to_s == 'has_one' 
        params += 'taillabel="1"'
      else
        params += 'taillabel="n"'
      end

      # Use double-headed arrows for habtm and has_many, :through
      if association.macro.to_s == 'has_and_belongs_to_many' ||
         (association.macro.to_s == 'has_many' && association.options[:through])
        if @habtm.include? "#{association.class_name} -> #{current_class.name}"
	  # habtm association already considered
          return
        else
          params += ', headlabel="n", arrowtail="normal"'
          @habtm << "#{current_class.name} -> #{association.class_name}"
        end
      end  
      # Print the edge
      print "\t\t#{node(current_class.name)} -> " +
            "#{node(association.class_name)} " +
            "[ #{params} ]\n"
    end
  end # process_association

end # class ModelsDiagram


class ControllersDiagram < AppDiagram

  # Generate controllers diagram
  def generate

    load_classes

    # DOT diagram header
    print "digraph controllers_diagram {\n" +
          "\tgraph[overlap=false, splines=true]\n"
    print_info "Controllers" if @options.label

    @app_controller = ApplicationController

    controllers_files = Dir.glob("app/controllers/**/*_controller.rb")
    controllers_files << 'app/controllers/application.rb'
    controllers_files.each do |c|

      # Extract the class name from the file name
      class_name = c.split('/')[2..-1].join('/').split('.').first.camelize

      # ApplicationController's file is 'application.rb'
      if class_name == 'Application' 
        class_name = 'ApplicationController' 
      end 

      process_class class_name.constantize

    end 
    print "}\n"
  end # generate

  private

  # Load controller classes
  def load_classes
    begin
      # ApplicationController must be loaded first
      require "app/controllers/application.rb" 
      Dir.glob("app/controllers/**/*_controller.rb") do |c| 
        require c
      end
    rescue LoadError
      print_error "controller classes"
      raise
    end
  end # load_classes

  # Proccess controller class
  def process_class(current_class)
    # Print the node
    if @options.brief
      print "\t#{node(current_class.name)}\n"
    elsif current_class.is_a? Class 
      print "\t#{node(current_class.name)} " +
            "[shape=Mrecord, label=\"{#{current_class.name}|"
      current_class.public_instance_methods(false).sort.each { |m|
        print "#{m}\\l" 
      } unless @options.hide_public
      print "|" 
      current_class.protected_instance_methods(false).sort.each { |m|
        print "#{m}\\l" 
      } unless @options.hide_protected
      print "|" 
      current_class.private_instance_methods(false).sort.each { |m|
        print "#{m}\\l" 
      } unless @options.hide_private
      print "}\"]\n" 
    elsif @options.modules && (current_class.is_a? Module)
        print "\t#{node(current_class.name)}" +
              "[shape=box, style=dotted, label=\"#{current_class.name}\"]\n"      
    end

    # Print the inheritance edge
    if @options.inheritance && 
       (@app_controller.subclasses.include? current_class.name)
      print "\t#{node(current_class.name)} -> " +
            "#{node(current_class.superclass.name)} " +
            "[arrowhead=\"onormal\"]\n"
    end

  end # process_class

end # class ControllersDiagram


# Main program

options = OptionsParser.parse ARGV

if options.command == 'models'
  diagram = ModelsDiagram.new options
elsif options.command == 'controllers'
  diagram = ControllersDiagram.new options
else
  $stderr.print "Error: You must supply a command\n" +
                "  (try #{APP_NAME} -h)\n\n"
  exit 1
end

if options.output
  old_stdout = $stdout
  begin
     $stdout = File.open(options.output, "w")
  rescue
     $stderr.print "Error: Cannot write to #{options.output}\n\n"
     exit 2
  end
end

diagram.generate

if options.out
  $stdout = old_stdout
end