gistfile1

# From http://blog.jayfields.com/2008/02/rake-task-overwriting.html
class Rake::Task
  def abandon
    @actions.clear
  end
end

OLD_MIGRATION = Rake::Task["db:migrate"]
Rake::Task["db:migrate"].abandon

OLD_REDO = Rake::Task["db:migrate:redo"]
Rake::Task["db:migrate:redo"].abandon

OLD_DOWN = Rake::Task["db:migrate:down"]
Rake::Task["db:migrate:redo"].abandon

OLD_UP = Rake::Task["db:migrate:up"]
Rake::Task["db:migrate:up"].abandon

namespace :db do
  task :migrate do
    OLD_MIGRATION.invoke
  end

  namespace :migrate do
    task :redo do
      ENV['VERSION'] = parse_version(ENV['VERSION'])
      OLD_REDO.invoke
    end

    task :down do
      ENV['VERSION'] = parse_version(ENV['VERSION'])
      OLD_DOWN.invoke
    end

    task :up do
      ENV['VERSION'] = parse_version(ENV['VERSION'])
      OLD_UP.invoke
    end
  end
end

def parse_version(version)
  # If we get passed a VERSION variable, and it is not a number
  # we look to see if a filename matches and reset based on that
  # number
  if version =~ /[^0-9]/
    # We have a string!
    files = Dir.glob(File.join(Rails.root, 'db', 'migrate', '*.rb')).select {|filename| filename =~ Regexp.new(version)}
    if files.length > 1
      files.sort!
      puts "That version matches a number of files, please pick one:"
      files.each_with_index do |filename, key|
        puts "#{key + 1}. #{File.basename(filename)}"
      end
      print "Which version do you want to migrate? "
      number = STDIN.gets
      file = files[number.chomp.to_i - 1]
    elsif files.length == 0
      puts "No files matched that string"
      exit
    else
      file = files.first
    end
    File.basename(file).match(/^(\d+)_/)[1]
  end
end