# +--------------------------------------------------------------------------+
# |  Licensed Materials - Property of IBM                                    |
# |                                                                          |
# | (C) Copyright IBM Corporation 2008, 2013.                                |
# +--------------------------------------------------------------------------+
# | This module complies with SQLAlchemy 0.8 and is                          |
# | Licensed under the Apache License, Version 2.0 (the "License");          |
# | you may not use this file except in compliance with the License.         |
# | You may obtain a copy of the License at                                  |
# | http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable |
# | law or agreed to in writing, software distributed under the License is   |
# | distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
# | KIND, either express or implied. See the License for the specific        |
# | language governing permissions and limitations under the License.        |
# +--------------------------------------------------------------------------+
# | Author: Jaimy Azle                                                       |
# | Contributor: Mike Bayer                                                  |
# +--------------------------------------------------------------------------+

raise NotImplementedError(
        "The zxjdbc dialect is not implemented at this time.")


# NOTE: it appears that to use zxjdbc, the "RETURNING" syntax
# must be installed in DB2, which appears to be optional.  It would
# be best if the RETURNING support were built into the base dialect
# and not be local to zxjdbc here.

from decimal import Decimal as _python_Decimal
from sqlalchemy import sql, util
from sqlalchemy import types as sa_types
from sqlalchemy.engine.base import FullyBufferedResultProxy, ResultProxy
from sqlalchemy.connectors.zxJDBC import ZxJDBCConnector
from .base import DB2Dialect, DB2ExecutionContext, DB2Compiler



class ReturningResultProxy(FullyBufferedResultProxy):

    """ResultProxy backed by the RETURNING ResultSet results."""

    def __init__(self, context, returning_row):
        self._returning_row = returning_row
        super(ReturningResultProxy, self).__init__(context)

    def _cursor_description(self):
        ret = []
        for c in self.context.compiled.returning_cols:
            if hasattr(c, 'name'):
                ret.append((c.name, c.type))
            else:
                ret.append((c.anon_label, c.type))
        return ret

    def _buffer_rows(self):
        return [self._returning_row]

class ReturningParam(object):

    """A bindparam value representing a RETURNING parameter.

    """

    def __init__(self, type):
        self.type = type

    def __eq__(self, other):
        if isinstance(other, ReturningParam):
            return self.type == other.type
        return NotImplemented

    def __ne__(self, other):
        if isinstance(other, ReturningParam):
            return self.type != other.type
        return NotImplemented

    def __repr__(self):
        kls = self.__class__
        return '<%s.%s object at 0x%x type=%s>' % (
                kls.__module__, kls.__name__, id(self),
                                                   self.type)

class DB2ExecutionContext_zxjdbc(DB2ExecutionContext):

    def pre_exec(self):
        if hasattr(self.compiled, 'returning_parameters'):
            self.statement = self.cursor.prepare(self.statement)

    def get_result_proxy(self):
        if hasattr(self.compiled, 'returning_parameters'):
            rrs = None
            try:
                try:
                    rrs = self.statement.__statement__.getReturnResultSet()
                    rrs.next()
                except SQLException, sqle:
                    msg = '%s [SQLCode: %d]' % (sqle.getMessage(), sqle.getErrorCode())
                    if sqle.getSQLState() is not None:
                        msg += ' [SQLState: %s]' % sqle.getSQLState()
                    raise zxJDBC.Error(msg)
                else:
                    row = tuple(self.cursor.datahandler.getPyObject(rrs, index, dbtype)
                                for index, dbtype in self.compiled.returning_parameters)
                    return ReturningResultProxy(self, row)
            finally:
                if rrs is not None:
                    try:
                        rrs.close()
                    except SQLException:
                        pass
                self.statement.close()

        return ResultProxy(self)

    def create_cursor(self):
        cursor = self._dbapi_connection.cursor()
        cursor.datahandler = self.dialect.DataHandler(cursor.datahandler)
        return cursor

class DB2Compiler_zxjdbc(DB2Compiler):

    def returning_clause(self, stmt, returning_cols):
        self.returning_cols = list(expression._select_iterables(returning_cols))

        # within_columns_clause=False so that labels (foo AS bar) don't render
        columns = [self.process(c, within_columns_clause=False, result_map=self.result_map)
                   for c in self.returning_cols]

        if not hasattr(self, 'returning_parameters'):
            self.returning_parameters = []

        binds = []
        for i, col in enumerate(self.returning_cols):
            dbtype = col.type.dialect_impl(self.dialect).get_dbapi_type(self.dialect.dbapi)
            self.returning_parameters.append((i + 1, dbtype))

            bindparam = sql.bindparam("ret_%d" % i, value=ReturningParam(dbtype))
            self.binds[bindparam.key] = bindparam
            binds.append(self.bindparam_string(self._truncate_bindparam(bindparam)))

        return 'RETURNING ' + ', '.join(columns) +  " INTO " + ", ".join(binds)

class DB2Dialect_zxjdbc(ZxJDBCConnector, DB2Dialect):

    supports_unicode_statements = supports_unicode_binds = \
    returns_unicode_strings = supports_unicode = False
    supports_sane_rowcount = False
    supports_sane_multi_rowcount = False

    jdbc_db_name = 'db2'
    jdbc_driver_name = 'com.ibm.db2.jcc.DB2Driver'

    statement_compiler = DB2Compiler_zxjdbc
    execution_ctx_cls = DB2ExecutionContext_zxjdbc

    @classmethod
    def dbapi(cls):

        global SQLException, zxJDBC
        from java.sql import SQLException, Types as java_Types
        from com.ziclix.python.sql import zxJDBC
        from com.ziclix.python.sql import FilterDataHandler

        # TODO: this should be somewhere else
        class IBM_DB2DataHandler(FilterDataHandler):

            def setJDBCObject(self, statement, index, object, dbtype=None):
                if type(object) is ReturningParam:
                    statement.registerReturnParameter(index, object.type)
                elif dbtype is None:
                    if (isinstance(object, int)):
                        statement.setObject(index, str(object), java_Types.BIGINT)
                    elif (isinstance(object, _python_Decimal)):
                        statement.setObject(index, str(object), java_Types.DECIMAL)
                    else:
                        statement.setObject(index, object)
                else:
                    FilterDataHandler.setJDBCObject(self, statement, index, object, dbtype)

        cls.DataHandler = IBM_DB2DataHandler
        return zxJDBC


class AS400Dialect_zxjdbc(DB2Dialect_zxjdbc):
    jdbc_db_name = 'as400'
    jdbc_driver_name = 'com.ibm.as400.access.AS400JDBCDriver'