module Mongrations
  class MongrationError < ::MongoMapper::Error; end

  class IrreversibleMigration < MongrationError#:nodoc:
  end

  class DuplicateMigrationVersionError < MongrationError#:nodoc:
    def initialize(version)
      super("Multiple migrations have the version number #{version}")
    end
  end

  class DuplicateMigrationNameError < MongrationError#:nodoc:
    def initialize(name)
      super("Multiple migrations have the name #{name}")
    end
  end

  class UnknownMigrationVersionError < MongrationError #:nodoc:
    def initialize(version)
      super("No migration with version number #{version}")
    end
  end

  class IllegalMigrationNameError < MongrationError#:nodoc:
    def initialize(name)
      super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed)")
    end
  end
end