#!/usr/bin/python
# -*- coding: UTF-8 -*-

import binascii
import hashlib
import random
import re
import string

import psycopg2

def pbkdf2( word, salt, iterations = 20000, hash_name = 'sha512' ):
    if salt.startswith( "pbkdf2$" ):
        stored_hash = salt
        _, hash_name, salt, iterations, h = salt.split( "$" )
        iterations = int( iterations )
        tested_hash = pbkdf2( word, salt, iterations, hash_name )
        
        return tested_hash == stored_hash
    
    else:
        h = hashlib.pbkdf2_hmac( hash_name, word, salt, iterations )
        h = binascii.hexlify( h )
        r = "$".join( map( str, [ hash_name, salt, iterations, h ] ) )
        
        return "pbkdf2$" + r

def random_data( N ):
    return ''.join( random.choice( string.ascii_uppercase + string.digits ) for _ in range( N ) )

def urlsplit( url ):
    data = re.match( '((?P<protocol>[^:]+)://)((?P<user>[^:]+)?(:(?P<password>[^@]+))?)?@(?P<host>[^:/]+)(:(?P<port>\d+))?(/(?P<database>[^&]+))?', url )
    return dict( [ ( key, data.group( key ) ) for key in [ 'user', 'password', 'host', 'port', 'database' ] ] )

class Database( object ):
    def __init__( self, url, docommit = True ):
        self.conn = psycopg2.connect( **urlsplit( url ) )
        self.docommit = docommit
            
    def cursor( self ):
        return self.conn.cursor()
    
    def commit( self ):
        if self.docommit:
            self.conn.commit()
    
    def close( self ):
        self.conn.close()
    
    def query( self, sql, *args, **kwargs ):
        c = self.conn.cursor()
        c.execute( sql, *args, **kwargs )
        return c
    
    def query_fetchone( self, sql ):
        return self.query( sql ).fetchone()
    
    def query_fetchall( self, sql ):
        return self.query( sql ).fetchall()
    
    def __enter__( self ):
        return self
    
    def __exit__( self, exc_type, exc_val, exc_tb ):
        self.commit()
        self.close()