from sqlalchemy.types import *

import json
import pickle
import copy
import uuid
import binascii
from galaxy.util.bunch import Bunch
from galaxy.util.aliaspickler import AliasPickleModule

# For monkeypatching BIGINT
import sqlalchemy.dialects.sqlite
import sqlalchemy.dialects.postgresql
import sqlalchemy.dialects.mysql

import logging
log = logging.getLogger( __name__ )

# Default JSON encoder and decoder
json_encoder = json.JSONEncoder( sort_keys=True )
json_decoder = json.JSONDecoder( )

def _sniffnfix_pg9_hex(value):
    """
    Sniff for and fix postgres 9 hex decoding issue
    """
    try:
        if value[0] == 'x':
            return binascii.unhexlify(value[1:])
        elif value.startswith( '\\x' ):
            return binascii.unhexlify( value[2:] )
        else:
            return value
    except Exception, ex:
        return value

class JSONType( TypeDecorator ):
    """
    Defines a JSONType for SQLAlchemy.  Takes a primitive as input and
    JSONifies it.  This should replace PickleType throughout Galaxy.
    """
    impl = LargeBinary

    def process_bind_param( self, value, dialect ):
        if value is None:
            return None
        return json_encoder.encode( value )

    def process_result_value( self, value, dialect ):
        if value is None:
            return None
        return json_decoder.decode( str( _sniffnfix_pg9_hex(value) ) )

    def copy_value( self, value ):
        # return json_decoder.decode( json_encoder.encode( value ) )
        return copy.deepcopy( value )

    def compare_values( self, x, y ):
        # return json_encoder.encode( x ) == json_encoder.encode( y )
        return ( x == y )

    def is_mutable( self ):
        return True

metadata_pickler = AliasPickleModule( {
    ( "cookbook.patterns", "Bunch" ) : ( "galaxy.util.bunch" , "Bunch" )
} )

class MetadataType( JSONType ):
    """
    Backward compatible metadata type. Can read pickles or JSON, but always
    writes in JSON.
    """
    def process_result_value( self, value, dialect ):
        if value is None:
            return None
        ret = None
        try:
            ret = metadata_pickler.loads( str( value ) )
            if ret:
                ret = dict( ret.__dict__ )
        except:
            try:
                ret = json_decoder.decode( str( _sniffnfix_pg9_hex(value) ) )
            except:
                ret = None
        return ret

class UUIDType(TypeDecorator):
    """
    Platform-independent UUID type.

    Based on http://docs.sqlalchemy.org/en/rel_0_8/core/types.html#backend-agnostic-guid-type
    Changed to remove sqlalchemy 0.8 specific code

    CHAR(32), storing as stringified hex values.
    """
    impl = CHAR

    def load_dialect_impl(self, dialect):
        return dialect.type_descriptor(CHAR(32))

    def process_bind_param(self, value, dialect):
        if value is None:
            return value
        else:
            if not isinstance(value, uuid.UUID):
                return "%.32x" % uuid.UUID(value)
            else:
                # hexstring
                return "%.32x" % value

    def process_result_value(self, value, dialect):
        if value is None:
            return value
        else:
            return uuid.UUID(value)


class TrimmedString( TypeDecorator ):
    impl = String
    def process_bind_param( self, value, dialect ):
        """Automatically truncate string values"""
        if self.impl.length and value is not None:
            value = value[0:self.impl.length]
        return value


#class BigInteger( Integer ):
    #"""
    #A type for bigger ``int`` integers.

    #Typically generates a ``BIGINT`` in DDL, and otherwise acts like
    #a normal :class:`Integer` on the Python side.

    #"""

#class BIGINT( BigInteger ):
    #"""The SQL BIGINT type."""

#class SLBigInteger( BigInteger ):
    #def get_col_spec( self ):
        #return "BIGINT"

#sqlalchemy.dialects.sqlite.SLBigInteger = SLBigInteger
#sqlalchemy.dialects.sqlite.colspecs[BigInteger] = SLBigInteger
#sqlalchemy.dialects.sqlite.ischema_names['BIGINT'] = SLBigInteger
#sqlalchemy.dialects.postgres.colspecs[BigInteger] = sqlalchemy.dialects.postgres.PGBigInteger
#sqlalchemy.dialects.mysql.colspecs[BigInteger] = sqlalchemy.dialects.mysql.MSBigInteger