ruby_parse_liquibase_change_log_to_migrations.rb

require 'nokogiri'

class String
  def underscore
    self.gsub(/::/, '/').
    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').
    tr("-", "_").
    downcase
  end
end

def foreign_key_migration_name(foreign_key)
  "add_#{foreign_key.attribute('referencedTableName')}_reference_to_#{foreign_key.attribute('baseTableName')}"
end

def create_table_migration_name(create_table)
  "create_table_#{create_table.attribute('tableName')}"
end

def create_index_migration_name(create_index)
  "add_#{create_index.children[1].attribute('name')}_index_for_#{create_index.attribute('tableName')}"
end

def add_unique_constraint_name(unique_constraint)
  "add_unique_constraint_#{unique_constraint.attribute('columnNames')}_to_#{unique_constraint.attribute('tableName')}"
end

def primary_key_name(primary_key)
  column_names = primary_key.attribute('columnNames').to_s.delete(' ').gsub(',', '_')
  "add_primary_key_#{column_names}_to_#{primary_key.attribute('tableName')}"
end


doc = Nokogiri::XML(File.open("liquibase_change_log.xml"))
header = File.open('header.xml', 'r').read
changeSets = doc.children[0].search('changeSet')

changeSets.each_with_index do |item, index|
  action = item.children[1].name
  element = item.children[1]
  if (action == 'createTable')
    name = create_table_migration_name(element)
  elsif (action == 'createIndex')
    name = create_index_migration_name(element)
  elsif (action == 'addForeignKeyConstraint')
    name = foreign_key_migration_name(element)
  elsif (action == 'addUniqueConstraint')
    name = add_unique_constraint_name(element)
  elsif (action == 'addPrimaryKey')
    name = primary_key_name(element)
  end


  filename = "migrations/#{(index+1).to_s.rjust(4, '0')}_#{name}.xml"
  File.open(filename, 'w') { |file| file.write("#{header}\n#{item.to_xml}") }
end