#!/usr/bin/env python
import sys
import os
import re
# import time
import logging
import argparse as arg
import psycopg2 as pg
from psycopg2.extensions import AsIs

from classes.CustomFormater import CustomFormatter
from classes.Timer import Timer

# Schema name is NAMEDATALEN-1 (PGSQL source code)
#  -> src/include/pg_config_manual.h
def check_schema_name(arg_value, pat=re.compile(r"^[a-z0-9A-Z]{1,63}$")):
    if not pat.match(arg_value):
        raise ValueError
    return arg_value


def parse_args():
    """
    Parse arguments
    """
    parser = arg.ArgumentParser('Process csv files from INSEE')

    parser.add_argument('--connection-file', '-f', 
            help='Postgresql connexion file',
            default='.pgconn'
    )
    
    # As whe use AsIs function to not include '' in our sql queries for schema
    # name, me mus ensure that it is not contains SQL special characters 
    # like comments --, final coma etc and avoid SQL injection
    parser.add_argument('--schema-name',
            help='Database schema name',
            type=check_schema_name,
            default='insee'
    )

    debug_group = parser.add_mutually_exclusive_group()
    debug_group.add_argument('--verbose', '-V',
            help='Verbose output',
            action='store_true')
    debug_group.add_argument('--debug', '-d',
            help='Activate debug mode',
            action='store_true')
    return parser.parse_args()


if __name__ == '__main__':
    args = parse_args()
    #logging.basicConfig(level=logging.DEBUG)
    logger = logging.getLogger()
    tty_handler = logging.StreamHandler()

    # create console handler with a higher log level
    tty_handler.setFormatter(CustomFormatter())
    logger.addHandler(tty_handler)
    
    if args.verbose is True:
        logger.setLevel(logging.INFO)
        logger.info('VERBOSE mode activated')
    
    if args.debug is True:
        logger.setLevel(logging.DEBUG)
        logger.debug('DEBUG mode activated')
    
    t = Timer(logger=logger.info)
    logging.debug('Import pgsql connection file {}'.format(args.connection_file))
    with open(args.connection_file) as cf:    
        pg_conn = cf.read()
    
    t.start('Delete schema')
    logger.debug('Delete schema {}'.format(args.schema_name))
    conn = pg.connect(pg_conn)
    with conn.cursor() as curs:
        try:
            curs.execute('DROP SCHEMA IF EXISTS %s CASCADE', 
                    (AsIs(args.schema_name),))
            conn.commit()
        except Exception as e:
            logger.error('Can\'t drop schema {}: {}'.format(
                args.schema_name,
                e
                )
            )
        
    t.stop()