import argparse
import hashlib
import psycopg2
import uuid

try:
    bytes = buffer
except:
    pass

parser = argparse.ArgumentParser()
parser.add_argument('username')
parser.add_argument('password')
parser.add_argument('database')
parser.add_argument('-H', '--host', default = 'localhost', help = 'default: localhost')
args = parser.parse_args()

def process_table(connection, table):
    c = connection.cursor()

    c.execute(r"ALTER TABLE {0} ADD COLUMN path_hash BYTEA NOT NULL DEFAULT E'\\0000'".format(table))

    hashes = dict()
    c.execute('SELECT path FROM {0}'.format(table))
    for row in c.fetchall():
        hashes[row[0]] = hashlib.sha1(row[0].encode('utf-8')).digest()
    c.executemany('UPDATE {0} SET path_hash=%s WHERE path=%s'.format(table), [ (bytes(h), p) for p, h in hashes.items() ])

    c.execute('CREATE UNIQUE INDEX index_{0}_path ON {0}(path_hash)'.format(table))

with psycopg2.connect(host = args.host, user = args.username, password = args.password, dbname = args.database) as conn:
    process_table(conn, 'folder')
    process_table(conn, 'track')