module ETL #:nodoc:
  module Control #:nodoc:
    # Source object which extracts data from a database using ActiveRecord.
    class DatabaseSource < Source
      # Initialize the source.
      #
      # Arguments:
      # * <tt>control</tt>: The ETL::Control::Control instance
      # * <tt>configuration</tt>: The configuration Hash
      # * <tt>definition</tt>: The source definition
      #
      # Required configuration options:
      # * <tt>:table</tt>: The source table name
      # * <tt>:database</tt>: The database name
      # 
      # Other options:
      # * <tt>:adapter</tt>: The adapter to use (defaults to :mysql)
      # * <tt>:username</tt>: The database username (defaults to 'root')
      # * <tt>:password</tt>: The password to the database (defaults to nothing)
      # * <tt>:host<tt>: The host for the database (defaults to 'localhost')
      def initialize(control, configuration, definition)
        super
        connect
      end
      
      def to_s
        "#{configuration[:host]}/#{configuration[:database]}"
      end
      
      # Returns each row from the source
      def each
        conn = ETL::ActiveRecord::Base.connection
        conn.select_all("SELECT * FROM #{configuration[:table]}").each do |row|
          yield row
        end
      end
      
      private
      # Connect to the database. 
      #
      # Required options:
      # * <tt>:database</tt>: The database name
      # 
      # Options:
      # * <tt>:adapter</tt>: The adapter to use (defaults to :mysql)
      # * <tt>:username</tt>: The database username (defaults to 'root')
      # * <tt>:password</tt>: The password to the database (defaults to nothing)
      # * <tt>:host<tt>: The host for the database (defaults to 'localhost')
      def connect
        ETL::ActiveRecord::Base.establish_connection(
            :adapter  => (configuration[:adapter] || :mysql),
            :username => (configuration[:username] || 'root'),
            :host     => (configuration[:host] || 'localhost'),
            :password => configuration[:password],
            :database => configuration[:database] 
        )
      end
    end
  end
end