namespace :db do
  task migrations2sql: :environment do |task|

    SQL_FILES_DIR = Rails.root.join('tmp', 'sql')
    FileUtils.rm_rf(SQL_FILES_DIR, secure: true)
    Dir.mkdir(SQL_FILES_DIR) unless File.exists?(SQL_FILES_DIR)

    TMP_FILE = Tempfile.new('migrations2sql')



    module ActiveRecord
      module AttributeAssignment
        def assign_attributes(new_attributes)
          return
        end
      end
    end



    ActiveRecord::Base.connection.class.class_eval do

      # it should think that indexes are not existed
      def index_name_exists?(table_name, index_name, default)
        false
      end

      alias :old_execute :execute

      # define our own execute
      def execute(sql, name = nil)

        # check for some DDL and DML statements
        if /^(alter|create|drop|delete|insert|update)/i.match sql
          p sql
          TMP_FILE.write "#{sql};\n"
        else
          # pass everything else to the aliased execute
          old_execute sql, name
        end
      end

    end


    migrations = ActiveRecord::Migrator.migrations(File.join(Rails.root, 'db'))

    migrations.each_with_index do |migration, i|
      migration.migrate(:up)

      begin
        version = migration.filename[/([0-9]+_[_a-z0-9]*\.?[_a-z0-9]*)?\.rb\z/, 1]
        filename = File.join(SQL_FILES_DIR, "V1_#{i}__#{version}.sql")
        TMP_FILE.rewind
        content = TMP_FILE.read
        file = File.open(filename, "w")
        file.write "-- #{migration.filename}\n\n"
        file.write content

        TMP_FILE.truncate(0)
        TMP_FILE.rewind
      rescue IOError => e
        p e
      ensure
        file.close unless file.nil?
      end
    end

    TMP_FILE.close
    TMP_FILE.unlink
  end



end