#!/usr/bin/env python3.2

import time

from pgtoolkit import toolbase
from pgtoolkit.pgmanager import OperationalError


class BatchUpdateTool(toolbase.SimpleTool):
    def __init__(self):
        toolbase.SimpleTool.__init__(self, name='batchupdate', desc='Run an UPDATE query until it does not update any rows.')
        self.parser.add_argument('--query', dest='query', type=str, help='Query to run. It should be constructed using subquery with LIMIT.')
        self.parser.add_argument('--sleep', dest='sleep', default=0, type=int, help='Sleep SLEEP seconds between subsequent queries.')
        self.init()

    def main(self):
        # connect DB
        rowcount = 1
        while rowcount > 0:
            print('query:', self.args.query)
            with self.pgm.cursor('target') as curs:
                try:
                    curs.execute(self.args.query, [])
                    rowcount = curs.rowcount
                    print('updated', rowcount)
                    curs.connection.commit()
                except (OperationalError, SystemError) as e:
                    print('Error:', str(e))
            print('sleep %s seconds' % self.args.sleep)
            time.sleep(self.args.sleep)


tool = BatchUpdateTool()
tool.main()