#!/usr/bin/ruby

# This script is used to update the Eclipse .classpath file for the master project; it is used when
# a module is added or removed, or when a src folder is added or removed from a module.
#
# It assumes the layout of each module conforms to the normal Maven structure.
#
# This script must be executed from the root project directory (the directory containing the master pom.xml, and containing
# the directories for the modules).

# TODO: Generated IDEA control files as well

require 'optparse'

# Rub gems:  Think of it as Maven for Ruby but not brain-damaged. See http://www.rubygems.org/read/book/1

require 'rubygems'

# This script requires the Ruby gem hpricot ("gem install hpricot"). It was built with version 0.6.
# http://code.whytheluckystiff.net/hpricot

require 'hpricot'

CLASSPATH_HEADER = [
  %Q{<?xml version="1.0" encoding="UTF-8"?>},
  %Q{<classpath>}
].freeze

CLASSPATH_TRAILER = [
  %Q{  <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>},
  %Q{  <classpathentry kind="con" path="org.maven.ide.eclipse.MAVEN2_CLASSPATH_CONTAINER/noworkspace"/>},
  %Q{  <classpathentry kind="output" path="bin"/>},
  %Q{</classpath>}
].freeze

# These may be overridden based on command line options

$project_only = false
$dryrun = false

$opts = OptionParser.new do |opts|
    opts.banner = "Usage: update-eclipse [options]"
  
    opts.on("-d", "--dry-run", "Show the generated POM but don't write anything") do
        $dryrun = true
    end
    
    opts.on("-p", "--project-only", "Update only the project control files, not the individual modules") do
      $project_only = true
    end
    
    opts.on("-h", "--help", "Help for this command") do
        puts opts
        exit
    end
    
end

def fail(message)
    puts "Error: #{message}"
    puts $opts
end

begin
    $opts.parse!
rescue OptionParser::InvalidOption
    fail $!
end

def exist(mod_name, folder)
  path = "#{mod_name}/#{folder}"

  if File.directory?(path) 
    yield path
  end
end

def add_source_folder(mod_name, folder, output_dir)
  exist(mod_name, folder) do |path|
    $project_classpath << %Q{  <classpathentry kind="src" output="#{output_dir}" path="#{path}"/>}
    $module_classpath <<  %Q{  <classpathentry kind="src" output="#{output_dir}"  path="#{folder}"/>}
  end
end

def add_class_folder(mod_name, folder)
  exist(mod_name, folder) do |path|
    $project_classpath <<    %Q{  <classpathentry kind="lib" path="#{path}"/>}
    $module_classpath << %Q{  <classpathentry kind="lib" path="#{folder}"/> }
  end
end

def process_module(mod_name)
  
  # quickstart, being an archetype, is the odd man out
  
  return if mod_name == "quickstart"
  
  $module_classpath = []
  
  add_source_folder(mod_name, "src/main/java", "bin");
  add_source_folder(mod_name, "src/test/java", "bin-test")
  
  add_class_folder(mod_name, "src/main/resources") 
  add_class_folder(mod_name, "src/test/resources") 
  
  write_control_files(mod_name, mod_name, $module_classpath) unless $project_only
  
end

def write_control_files(folder,  project_name, classpath)
  
  lines = CLASSPATH_HEADER.dup.concat(classpath).concat(CLASSPATH_TRAILER)
  
  write_lines("#{folder}/.classpath", lines)
  
  lines = [ 
"<projectDescription>",
"  <name>#{project_name}</name>",
"  <comment></comment>",
"  <projects>",
"  </projects>",
"  <buildSpec>",
"    <buildCommand>",
"      <name>org.eclipse.jdt.core.javabuilder</name>",
"      <arguments>",
"      </arguments>",
"    </buildCommand>",
"    <buildCommand>",
"      <name>org.maven.ide.eclipse.maven2Builder</name>",
"      <arguments>",
"      </arguments>",
"     </buildCommand>",
"  </buildSpec>",
"  <natures>",
"    <nature>org.eclipse.jdt.core.javanature</nature>",
"    <nature>org.maven.ide.eclipse.maven2Nature</nature>",
"  </natures>",
"</projectDescription>"
]
  
  write_lines("#{folder}/.project", lines)
  
end

def write_lines(file, lines)
  if $dryrun
    puts "Generated #{file}:\n"
    lines.each { |s| puts s }
    puts
    return
  end
  
  puts "Writing #{file} ..."
  
  File.open(file, "w") do |file|
   lines.each do |line| 
      file.print line 
      file.print "\n"
    end
  end
  
end

$master_pom = open("pom.xml") do |f|
    Hpricot.XML(f)
end


# We're going to build up the project classpath a line at a time.  This part is always the same:

$project_classpath = []

$modules = []

($master_pom/"project/modules/module").each { |elem| $modules << elem.inner_html }

# Add entries for each module

$modules.sort.each { |mod_name| process_module(mod_name) }

# Write out the updated .classpath

write_control_files(".", "datatech",  $project_classpath)

puts "Updated .classpath across project."