# Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2 of the
# License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
# 02110-1301  USA

import random
import os.path

from wb import DefineModule
from workbench import db_driver
from workbench.utils import find_object_with_name
from workbench.exceptions import NotConnectedError

import grt
import SQLEXT as constant


ModuleInfo = DefineModule(name= "DbGenericRE", author= "Oracle Corp.", version="1.0")


class GenericReverseEngineering(object):
    _connections = {}


    @classmethod
    def check_interruption(cls):
        if grt.query_status():
            raise grt.UserInterrupt()


    @classmethod
    def find_datatype_object(cls, catalog, datatype_name):
        ''' Finds the datatype object corresponding to the given datatype name.

        Returns: a tuple of the form (is_simple_datatype, datatype) where:
            is_simple_datatype: True if the datatype was found among the simple datatypes for
                                its corresponding RDBMS
            datatype:           The actual datatype object. None if not found
        '''
        simple_types = cls._rdbms.simpleDatatypes
        user_types = catalog.userDatatypes
        for simple_type in simple_types:
            if datatype_name == simple_type.name or datatype_name in simple_type.synonyms:
                return (True, simple_type)
        for user_type in user_types:
            if datatype_name == user_type.name:
                return (False, user_type)
        return (False, None)

    @classmethod
    def get_connection(cls, connection_object):
        if connection_object.__id__ in cls._connections:
            return cls._connections[connection_object.__id__]["connection"]
        else:
            raise NotConnectedError("No open connection to %s" % connection_object.hostIdentifier)

    # Note: try to avoid executing SQL code within this module
    @classmethod
    def execute_query(cls, connection_object, query, *args, **kwargs):
        """Retrieves a connection and executes the given query returning a cursor to iterate over results.

        The remaining positional and keyword arguments are passed with the query to the execute function
        """
        return cls.get_connection(connection_object).cursor().execute(query, *args, **kwargs)


    @classmethod
    def initializeDBMSInfo(cls, xml_data_path):
        cls._rdbms = grt.unserialize(os.path.join(ModuleInfo.moduleDataDirectory, xml_data_path))
        grt.root.wb.rdbmsMgmt.rdbms.append(cls._rdbms)
        return cls._rdbms
    
    @classmethod
    def getDataSourceNames(cls):
        result = grt.List(grt.STRING)
        import pyodbc
        sources = pyodbc.dataSources()
        for key, value in sources.items():
            result.append("%s|%s (%s)" % (key, key, value))
        return result


    @classmethod
    def getSupportedObjectTypes(cls):
        return [("tables", "db.Table", "Tables"), 
               ]


    @classmethod
    def quoteIdentifier(cls, name):
        return '"%s"' % name.replace('"', '\"')

    @classmethod
    def fullyQualifiedObjectName(cls, obj):
        owner = obj.owner
        if owner and isinstance(owner, grt.classes.db_Schema):
            if owner.owner and isinstance(owner.owner, grt.classes.db_Catalog):
                return cls.quoteIdentifier(owner.owner.name)+"."+cls.quoteIdentifier(owner.name)+"."+cls.quoteIdentifier(obj.name)
        elif owner and isinstance(owner, grt.classes.db_Catalog):
            return cls.quoteIdentifier(owner.name)+"."+cls.quoteIdentifier(obj.name)
        return cls.quoteIdentifier(obj.name)


    #########  Connection related functions #########
    @classmethod
    def connect(cls, connection, password):
        '''Establishes a connection to the server and stores the connection object in the connections pool.

        It first looks for a connection with the given connection parameters in the connections pool to
        reuse existent connections. If such connection is found it queries the server to ensure that the
        connection is alive and reestablishes it if is dead. If no suitable connection is found in the
        connections pool, a new one is created and stored in the pool.

        Parameters:
        ===========
            connection:  an object of the class db_mgmt_Connection storing the parameters
                         for the connection.
            password:    a string with the password to use for the connection.
        '''
        try:
            con = cls.get_connection(connection)
            try:
                if not con.cursor().execute('SELECT 1'):
                    raise Exception("connection error")
            except Exception, exc:
                grt.send_info("Connection to %s apparently lost, reconnecting..." % connection.hostIdentifier)
                raise NotConnectedError("Connection error")
        except NotConnectedError, exc:
            grt.send_info("Connecting to %s..." % connection.hostIdentifier)
            con = db_driver.connect(connection, password)
            if not con:
                grt.send_error('Connection failed', str(exc))
                raise
            grt.send_info("Connected")
            cls._connections[connection.__id__] = {"connection": con}
        return 1


    @classmethod
    def disconnect(cls, connection):
        if connection.__id__ in cls._connections:
            cls._connections[connection.__id__]['connection'].close()
            del cls._connections[connection.__id__]
        return 0

    @classmethod
    def isConnected(cls, connection):
        return 1 if connection.__id__ in cls._connections else 0


    #########  Exploratory functions (these only return useful info without reverse engineering) #########

    @classmethod
    def getTargetDBMSName(cls):
        return 'Generic'

    @classmethod
    def getServerVersion(cls, connection):
        """Returns a GrtVersion instance containing information about the server version."""
        
        # Note: Not implemented. This returns a predefined default server version for compatibility sake.
        version = grt.classes.GrtVersion()
        version.majorNumber, version.minorNumber, version.releaseNumber, version.buildNumber = 1, 0, 0, 0
        return version

    @classmethod
    def getCatalogNames(cls, connection):
        """Returns a list of the available catalogs.

        [NOTE] This will in fact return the name of the database we are connected to.
        """
        return list(set(row[0] for row in cls.get_connection(connection).cursor().tables())) 


    @classmethod
    def getSchemaNames(cls, connection, catalog_name):
        """Returns a list of schemata for the given connection object."""

        return list(set(row[1] for row in cls.get_connection(connection).cursor().tables(catalog=catalog_name)))


    @classmethod
    def getTableNames(cls, connection, catalog_name, schema_name):
        return list(set(row.table_name for row in 
                    cls.get_connection(connection).cursor().tables(catalog=catalog_name, schema=schema_name) if row.table_type=='TABLE'))


    @classmethod
    def getViewNames(cls, connection, catalog_name, schema_name):
        return list(set(row.table_name for row in 
                    cls.get_connection(connection).cursor().tables(catalog=catalog_name, schema=schema_name) if row.table_type=='VIEW'))


    @classmethod
    def getTriggerNames(cls, connection, catalog_name, schema_name):
        return []


    @classmethod
    def getProcedureNames(cls, connection, catalog_name, schema_name):
        return list(set(row.procedure_name for row in 
                    cls.get_connection(connection).cursor().procedures(catalog=catalog_name, schema=schema_name) ))


    @classmethod
    def getFunctionNames(cls, connection, catalog_name, schema_name):
        return []


    #########  Reverse Engineering functions #########

    @classmethod
    def reverseEngineer(cls, connection, catalog_name, schemata_list, context):
        grt.send_progress(0, "Reverse engineering catalog information")
        cls.check_interruption()
        catalog = cls.reverseEngineerCatalog(connection, catalog_name)

        # calculate total workload 1st
        grt.send_progress(0.1, 'Preparing...')
        table_count_per_schema = {}
        view_count_per_schema = {}
        routine_count_per_schema = {}
        trigger_count_per_schema = {}
        total_count_per_schema = {}

        get_tables = context.get("reverseEngineerTables", True)
        get_triggers = context.get("reverseEngineerTriggers", True)
        get_views = context.get("reverseEngineerViews", True)
        get_routines = context.get("reverseEngineerRoutines", True)

        # 10% of the progress is for preparation
        total = 1e-10  # total should not be zero to avoid DivisionByZero exceptions
        i = 0.0
        accumulated_progress = 0.1
        for schema_name in schemata_list:
            cls.check_interruption()
            table_count_per_schema[schema_name] = len(cls.getTableNames(connection, catalog_name, schema_name)) if get_tables else 0
            view_count_per_schema[schema_name] = len(cls.getViewNames(connection, catalog_name, schema_name)) if get_views else 0
            cls.check_interruption()
            routine_count_per_schema[schema_name] = len(cls.getProcedureNames(connection, catalog_name, schema_name)) + len(cls.getFunctionNames(connection, catalog_name, schema_name)) if get_routines else 0
            trigger_count_per_schema[schema_name] = len(cls.getTriggerNames(connection, catalog_name, schema_name)) if get_triggers else 0

            total_count_per_schema[schema_name] = (table_count_per_schema[schema_name] + view_count_per_schema[schema_name] +
                                                   routine_count_per_schema[schema_name] + trigger_count_per_schema[schema_name] + 1e-10)
            total += total_count_per_schema[schema_name]

            grt.send_progress(accumulated_progress + 0.1 * (i / (len(schemata_list) + 1e-10) ), "Gathered stats for %s" % schema_name)
            i += 1.0

        # Now take 60% in the first pass of reverse engineering:
        accumulated_progress = 0.2
        for schema_name in schemata_list:
            schema_progress_share = 0.6 * (total_count_per_schema.get(schema_name, 0.0) / total)
            schema = find_object_with_name(catalog.schemata, schema_name) 

            if schema:
                # Reverse engineer tables:
                step_progress_share = schema_progress_share * (table_count_per_schema[schema_name] / (total_count_per_schema[schema_name] + 1e-10))
                if get_tables:
                    cls.check_interruption()
                    grt.send_info('Reverse engineering tables from %s' % schema_name)
                    grt.begin_progress_step(accumulated_progress, accumulated_progress + step_progress_share)
                    # Remove previous first pass marks that may exist if the user goes back and attempt rev eng again:
                    progress_flags = cls._connections[connection.__id__].setdefault('_rev_eng_progress_flags', set())
                    progress_flags.discard('%s_tables_first_pass' % schema_name)
                    cls.reverseEngineerTables(connection, schema)
                    grt.end_progress_step()
        
                accumulated_progress += step_progress_share
                grt.send_progress(accumulated_progress, 'First pass of table reverse engineering for schema %s completed!' % schema_name)
        
                # Reverse engineer views:
                step_progress_share = schema_progress_share * (view_count_per_schema[schema_name] / (total_count_per_schema[schema_name] + 1e-10))
                if get_views:
                    cls.check_interruption()
                    grt.send_info('Reverse engineering views from %s' % schema_name)
                    grt.begin_progress_step(accumulated_progress, accumulated_progress + step_progress_share)
                    cls.reverseEngineerViews(connection, schema)
                    grt.end_progress_step()
        
                accumulated_progress += step_progress_share
                grt.send_progress(accumulated_progress, 'Reverse engineering of views for schema %s completed!' % schema_name)
        
                # Reverse engineer routines:
                step_progress_share = schema_progress_share * (routine_count_per_schema[schema_name] / (total_count_per_schema[schema_name] + 1e-10))
                if get_routines:
                    cls.check_interruption()
                    grt.send_info('Reverse engineering routines from %s' % schema_name)
                    grt.begin_progress_step(accumulated_progress, accumulated_progress + step_progress_share)
                    grt.begin_progress_step(0.0, 0.5)
                    cls.reverseEngineerProcedures(connection, schema)
                    cls.check_interruption()
                    grt.end_progress_step()
                    grt.begin_progress_step(0.5, 1.0)
                    reverseEngineerFunctions(connection, schema)
                    grt.end_progress_step()
                    grt.end_progress_step()
        
                accumulated_progress += step_progress_share
                grt.send_progress(accumulated_progress, 'Reverse engineering of routines for schema %s completed!' % schema_name)
        
                # Reverse engineer triggers:
                step_progress_share = schema_progress_share * (trigger_count_per_schema[schema_name] / (total_count_per_schema[schema_name] + 1e-10))
                if get_triggers:
                    cls.check_interruption()
                    grt.send_info('Reverse engineering triggers from %s' % schema_name)
                    grt.begin_progress_step(accumulated_progress, accumulated_progress + step_progress_share)
                    cls.reverseEngineerTriggers(connection, schema)
                    grt.end_progress_step()
        
                accumulated_progress = 0.8
                grt.send_progress(accumulated_progress, 'Reverse engineering of triggers for schema %s completed!' % schema_name)
            else:  # No schema with the given name was found
                grt.send_warning('The schema %s was not found in the catalog %s. Skipping it.' % (schema_name, catalog_name) )
                
        # Now the second pass for reverse engineering tables:
        if get_tables:
            total_tables = sum(table_count_per_schema[schema.name] for schema in catalog.schemata if schema.name in schemata_list)
            for schema in catalog.schemata:
                if schema.name not in schemata_list:
                    continue
                cls.check_interruption()
                step_progress_share = 0.2 * (table_count_per_schema[schema.name] / (total_tables + 1e-10))
                grt.send_info('Reverse engineering foreign keys for tables in schema %s' % schema.name)
                grt.begin_progress_step(accumulated_progress, accumulated_progress + step_progress_share)
                cls.reverseEngineerTables(connection, schema)
                grt.end_progress_step()
        
                accumulated_progress += step_progress_share
                grt.send_progress(accumulated_progress, 'Second pass of table reverse engineering for schema %s completed!' % schema_name)
            

        grt.send_progress(1.0, 'Reverse engineering completed!')
        return catalog


    @classmethod
    def reverseEngineerUserDatatypes(cls, connection, catalog):
        catalog.simpleDatatypes.remove_all()
        for type_row in cls.get_connection(connection).cursor().getTypeInfo(catalog=catalog.name):  # FIXME: there are duplicated names in this resultset
            simple_datatype = grt.classes.db_SimpleDatatype()
            simple_datatype.name = type_row[0]
            simple_datatype.characterMaximumLength = simple_datatype.characterOctetLength = simple_datatype.numericPrecision = simple_datatype.dateTimePrecision = type_row[2] if isinstance(type_row[2], int) else -1
            if isinstance(type_row[17], int):
                simple_datatype.numericPrecisionRadix = type_row[17]
            if isinstance(type_row[14], int):
                simple_datatype.numericScale = type_row[14]
            parameter_format_type_mapping = { 0: 0, # none
                                              1: 2, # [(n)]
                                              2: 6, # [(m[, n])]
                                            }
            if type_row[5] is not None:  # parameter format
                simple_datatype.parameterFormatType = parameter_format_type_mapping.get(len(type_row[5].split(',')), 0)
            else:
                simple_datatype.parameterFormatType = 0

            simple_datatype.needsQuotes = type_row[3] in ["N'", "'"]
            
            catalog.simpleDatatypes.append(simple_datatype)


    @classmethod
    def reverseEngineerCatalog(cls, connection, catalog_name):
        catalog = grt.classes.db_Catalog()
        catalog.name = catalog_name
        
        cls.reverseEngineerUserDatatypes(connection, catalog)

        schemata_names = cls.getSchemaNames(connection, catalog_name) or ['']
        catalog.schemata.remove_all()
        for schema_name in schemata_names:
            schema = grt.classes.db_Schema()
            schema.name = schema_name
            schema.owner = catalog
            if hasattr(cls, 'reverseEngineerSequences'):
                cls.reverseEngineerSequences(connection, schema)
            catalog.schemata.append(schema)
        return catalog

    @classmethod
    def reverseEngineerTables(cls, connection, schema):
        # Since there are some reverse engineering stages that requires all table names and table columns
        # in the database to be set, these should be done after a first pass that rev engs their requirements
        progress_flags = cls._connections[connection.__id__].setdefault('_rev_eng_progress_flags', [])
        is_first_pass = not ('%s_tables_first_pass' % schema.name) in progress_flags

        if is_first_pass:
            catalog = schema.owner
            schema.tables.remove_all()
            table_names = cls.getTableNames(connection, catalog.name, schema.name)
            getCommentForTable = cls.getCommentForTable if hasattr(cls, 'getCommentForTable') else lambda conn, tbl:''
            total = len(table_names) + 1e-10
            i = 0.0
            for table_name in table_names:
                grt.send_progress(i / total, 'Retrieving table %s.%s...' % (schema.name, table_name))
                table = grt.classes.db_Table()
                table.name = table_name
                schema.tables.append(table)
                table.owner = schema
                table.comment = getCommentForTable(connection, table)
        
                cls.reverseEngineerTableColumns(connection, table)
                cls.reverseEngineerTablePK(connection, table)
                cls.reverseEngineerTableIndices(connection, table)
        
                i += 1.0
            progress_flags.add('%s_tables_first_pass' % schema.name)
        else:  # Second pass
            i = 0.0
            total = len(schema.tables) + 1e-10
            cls._connections[connection.__id__]['fk_names'] = {}
            for table in schema.tables:
                cls.reverseEngineerTableFKs(connection, table)
                grt.send_progress(i / total, 'Reverse engineering of foreign keys in table %s.%s completed' % (schema.name, table.name))
                i += 1.0

        return 0

    @classmethod
    def reverseEngineerTableColumns(cls, connection, table):
        schema = table.owner
        catalog = schema.owner

        simple_datatypes_list = [ datatype.name.upper() for datatype in catalog.simpleDatatypes ]
        user_datatypes_list   = [ datatype.name.upper() for datatype in catalog.userDatatypes ]

        odbc_datatypes = dict( (dtype.data_type, dtype.type_name) for dtype in cls.get_connection(connection).cursor().getTypeInfo() )

        table_columns = cls.get_connection(connection).cursor().columns(catalog=catalog.name, schema=schema.name, table=table.name)
        for column_info in table_columns:
            column = grt.classes.db_Column()
            column.name = column_info[3]  # column_name
            column.isNotNull = column_info[17] == 'YES'  # is_nullable
            column.length = column_info[6]  # column_size
            column.scale = column_info[8]  # decimal_digits
            column.precision = column_info[6]  # column_size

            datatype = None
            try:
                type_name = odbc_datatypes[column_info[4]].upper()  # data_type
                datatype = simple_datatypes_list.index(type_name)
            except (KeyError, ValueError):
                try:
                    user_datatype = catalog.userDatatypes[user_datatypes_list.index(type_name)]
                except (ValueError, TypeError, NameError):
                    user_datatype = None
                    datatype = simple_datatypes_list.index('VARCHAR')
                    column.length = 255
                    msg = 'Column datatype "%s" for column "%s" in table "%s.%s" reverse engineered as VARCHAR(255)' % (type_name, column.name, schema.name, table.name)
                    grt.send_warning('%s reverseEngineerTableColumns: ' % cls.getTargetDBMSName() + msg)
                else:
                    datatype = None
                    column.userType = user_datatype

            if isinstance(datatype, int):
                column.simpleType = catalog.simpleDatatypes[datatype]

            table.addColumn(column)

        return 0


    @classmethod
    def reverseEngineerTablePK(cls, connection, table):
        """Reverse engineers the primary key(s) for the given table."""

        schema = table.owner
        catalog = schema.owner


        if len(table.columns) == 0:  # Table must have columns reverse engineered before we can rev eng its primary key(s)
            grt.send_error('Migration: reverseEngineerTablePKAndIndices: Reverse engineer of table %s was attempted but the table has no columns attribute' % table.name)
            return 1
        
        # Find the index name associated with the PK:
        pk_index_rows = cls.get_connection(connection).cursor().primaryKeys(catalog=catalog.name, schema=schema.name, table=table.name).fetchall()
        pk_index_name = pk_index_rows[0].pk_name if pk_index_rows else ''

        indices_dict = {}  # Map the indices names to their respective columns:
        for row in cls.get_connection(connection).cursor().statistics(catalog=catalog.name, schema=schema.name, table=table.name):
            if row.type == constant.SQL_TABLE_STAT:  # this entry is not an index
                continue
            indices_dict.setdefault(row.index_name, []).append(row)

        if pk_index_name not in indices_dict:  # The primary key is not listed in cursor().statistics
            from collections import namedtuple
            Row = namedtuple('IndexRow', ['table_cat', 'table_schem', 'table_name', 'non_unique', 'index_qualifier',
                                          'index_name', 'type', 'ordinal_position', 'column_name', 'asc_or_desc',
                                          'cardinality', 'pages', 'filter_condition'])
            for pk_index_row in pk_index_rows:
                row = Row(None, schema.name, table.name, 0, None, pk_index_name, 1, 1, pk_index_row.column_name, 'A', None, None, None)
                indices_dict.setdefault(pk_index_name, []).append(row)
        
        for index_name, row_list in indices_dict.iteritems():
            index = grt.classes.db_Index()
            index.name = index_name
            index.isPrimary = 1 if index_name == pk_index_name else 0
            index.unique = not row_list[0].non_unique
            index.indexType = 'UNIQUE' if index.unique else 'INDEX'
    #        index.hasFilter = False  # TODO: Find out if there's a way to determine this

            # Get the columns for the index:
            for row in sorted(row_list, key=lambda elem: elem[7]):  # Sorted by ordinal_position
                column = find_object_with_name(table.columns, row.column_name)
                if column:
                    index_column = grt.classes.db_IndexColumn()
                    index_column.name = index_name + '.' + row.column_name
                    index_column.referencedColumn = column
                    index.columns.append(index_column)
            table.addIndex(index)

            if index.isPrimary:
                table.primaryKey = index

        return 0


    @classmethod
    def reverseEngineerTableIndices(cls, connection, table):
        pass  # Indices already reverse engineered in reverseEngineerTablePK


    @classmethod
    def reverseEngineerTableFKs(cls, connection, table):
        """Reverse engineers the foreign keys for the given table."""

        def get_action(value):
            if value is None:
                return ''
            elif value == constant.SQL_CASCADE:
                return 'CASCADE'
            elif value == constant.SQL_RESTRICT:
                return 'RESTRICT'
            elif value == constant.SQL_SET_NULL:
                return 'SET NULL'
            elif value == constant.SQL_NO_ACTION:
                return 'NO ACTION'
            elif value == constant.SQL_SET_DEFAULT:
                return 'SET DEFAULT'
            else:
                return ''
            
        def process_fk(catalog, table, fk_name, fk_rows):
            foreign_key = grt.classes.db_ForeignKey()
            if fk_name in cls._connections[connection.__id__]['fk_names']:
                while True:
                    suffix = '_%06d' % random.randint(0, 999999)
                    if fk_name + suffix not in cls._connections[connection.__id__]['fk_names']:
                        break
                fk_name += suffix
            foreign_key.name = fk_name
            foreign_key.owner = table
            foreign_key.deleteRule = get_action(fk_rows[0].delete_rule)
            foreign_key.updateRule = get_action(fk_rows[0].update_rule)
            foreign_key.modelOnly = 0
            
            # Find the referenced table:
            referenced_schema = find_object_with_name(catalog.schemata, fk_rows[0].pktable_schem) if fk_rows[0].pktable_schem else schema
            foreign_key.referencedTable = find_object_with_name(referenced_schema.tables, fk_rows[0].pktable_name) if fk_rows[0].pktable_name else table
            
            for fk_row in fk_rows:
                column = find_object_with_name(table.columns, fk_row.fkcolumn_name)
                if not column:
                    grt.send_error('Migration: reverseEngineerTableFKs: Column "%s" not found in table "%s"' % (fk_row.fkcolumn_name, table.name) )
                    continue

                ref_column = find_object_with_name(foreign_key.referencedTable.columns, fk_row.pkcolumn_name)
                if not ref_column:
                    grt.send_error('Migration: reverseEngineerTableFKs: Column "%s" not found in table "%s"' % (fk_row.pkcolumn_name, foreign_key.referencedTable.name) )
                    continue
                
                foreign_key.columns.append(column)
                foreign_key.referencedColumns.append(ref_column)

            cls._connections[connection.__id__]['fk_names'][foreign_key.name] = table 
            table.foreignKeys.append(foreign_key)
                

        if len(table.columns) == 0:
            grt.send_error('Migration: reverseEngineerTableFKs: Reverse engineer of table %s was attempted but the table has no columns attribute' % table.name)
            return 1    # Table must have columns reverse engineered before we can rev eng its indices

        catalog = table.owner.owner
        schema = table.owner
        table.foreignKeys.remove_all()
        fk_dict = {}  # Map the foreign key names to their respective columns:
        for row in cls.get_connection(connection).cursor().foreignKeys(foreignSchema=schema.name, foreignTable=table.name):
            fk_dict.setdefault(row.fk_name, []).append(row)

        for fk_name, fk_columns in fk_dict.iteritems():
            if not fk_name:  # If there are unnamed fks we might have several fks merged, need to separate them
                # Partition the list based on key_seq so that if the key_seq list is, for instance, [1, 2, 3, 1, 2, 1]
                # we can have [ [1, 2, 3], [1, 2], [1] ]
                indices = [idx for idx, item in enumerate(fk_columns) if item.key_seq == 1]
                slices = [fk_columns[i:j] for i, j in zip(indices, indices+[None])]
                random_names = ['FK_generated_%06d' % id for id in random.sample(range(1000000), len(slices))] # Random names for each fk
                for slice, random_name in zip(slices, random_names):
                    if slice:
                        process_fk(catalog, table, random_name, slice)
            else:
                process_fk(catalog, table, fk_name, fk_columns)
        return 0


    @classmethod
    def reverseEngineerViews(cls, connection, schema):
        for view_name in cls.getViewNames(connection, schema.owner.name, schema.name):
            grt.send_info('%s reverseEngineerViews: Cannot reverse engineer view "%s"' % (cls.getTargetDBMSName(), view_name))
        return 0


    @classmethod
    def reverseEngineerProcedures(cls, connection, schema):
        # Unfortunately it seems that there's no way to get the SQL definition of a store procedure/function with ODBC
        for procedure_name in cls.getProcedureNames(connection, schema.owner.name, schema.name):
            grt.send_info('%s reverseEngineerProcedures: Cannot reverse engineer procedure "%s"' % (cls.getTargetDBMSName(), procedure_name))
        return 0


    @classmethod
    def reverseEngineerFunctions(cls, connection, schema):
        # Unfortunately it seems that there's no way to get the SQL definition of a store procedure/function with ODBC
        for function_name in cls.getFunctionNames(connection, schema.owner.name, schema.name):
            grt.send_info('%s reverseEngineerFunctions: Cannot reverse engineer function "%s"' % (cls.getTargetDBMSName(), function_name))
        return 0


    @classmethod
    def reverseEngineerTriggers(cls, connection, schema):
        # Unfortunately it seems that there's no way to get the SQL definition of a trigger with ODBC
        for trigger_name in cls.getTriggerNames(connection, schema.owner.name, schema.name):
            grt.send_info('%s reverseEngineerTriggers: Cannot reverse engineer trigger "%s"' % (cls.getTargetDBMSName(), trigger_name))
        return 0
    
###############################################################################################################

@ModuleInfo.export(grt.classes.db_mgmt_Rdbms)
def initializeDBMSInfo():
    return GenericReverseEngineering.initializeDBMSInfo('generic_rdbms_info.xml')

@ModuleInfo.export((grt.LIST, grt.STRING))
def getDataSourceNames():
    return GenericReverseEngineering.getDataSourceNames()


@ModuleInfo.export(grt.LIST)
def getSupportedObjectTypes():
    return GenericReverseEngineering.getSupportedObjectTypes()


@ModuleInfo.export(grt.STRING, grt.STRING)
def quoteIdentifier(name):
    return GenericReverseEngineering.quoteIdentifier(name)


@ModuleInfo.export(grt.STRING, grt.classes.GrtNamedObject)
def fullyQualifiedObjectName(obj):
    return GenericReverseEngineering.fullyQualifiedObjectName(obj)


@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.STRING)
def connect(connection, password):
    return GenericReverseEngineering.connect(connection, password)


@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection)
def disconnect(connection):
    return GenericReverseEngineering.disconnect(connection)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection)
def isConnected(connection):
    return GenericReverseEngineering.isConnected(connection)

@ModuleInfo.export(grt.STRING)
def getTargetDBMSName():
    return GenericReverseEngineering.getTargetDBMSName()

@ModuleInfo.export(grt.classes.GrtVersion, grt.classes.db_mgmt_Connection)
def getServerVersion(connection):
    return GenericReverseEngineering.getServerVersion(connection)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection)
def getCatalogNames(connection):
    return GenericReverseEngineering.getCatalogNames(connection)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING)
def getSchemaNames(connection, catalog_name):
    return GenericReverseEngineering.getSchemaNames(connection, catalog_name)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING, grt.STRING)
def getTableNames(connection, catalog_name, schema_name):
    return GenericReverseEngineering.getTableNames(connection, catalog_name, schema_name)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING, grt.STRING)
def getViewNames(connection, catalog_name, schema_name):
    return GenericReverseEngineering.getViewNames(connection, catalog_name, schema_name)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING, grt.STRING)
def getTriggerNames(connection, catalog_name, schema_name):
    return GenericReverseEngineering.getTriggerNames(connection, catalog_name, schema_name)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING, grt.STRING)
def getProcedureNames(connection, catalog_name, schema_name):
    return GenericReverseEngineering.getProcedureNames(connection, catalog_name, schema_name)

@ModuleInfo.export(grt.LIST, grt.classes.db_mgmt_Connection, grt.STRING, grt.STRING)
def getFunctionNames(connection, catalog_name, schema_name):
    return GenericReverseEngineering.getFunctionNames(connection, catalog_name, schema_name)

@ModuleInfo.export(grt.classes.db_Catalog, grt.classes.db_mgmt_Connection, grt.STRING, (grt.LIST, grt.STRING), grt.DICT)
def reverseEngineer(connection, catalog_name, schemata_list, context):
    return GenericReverseEngineering.reverseEngineer(connection, catalog_name, schemata_list, context)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Catalog)
def reverseEngineerUserDatatypes(connection, catalog):
    return GenericReverseEngineering.reverseEngineerUserDatatypes(connection, catalog)

@ModuleInfo.export(grt.classes.db_Catalog, grt.classes.db_mgmt_Connection, grt.STRING)
def reverseEngineerCatalog(connection, catalog_name):
    return GenericReverseEngineering.reverseEngineerCatalog(connection, catalog_name)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Schema)
def reverseEngineerTables(connection, schema):
    return GenericReverseEngineering.reverseEngineerTables(connection, schema)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Schema)
def reverseEngineerViews(connection, schema):
    return GenericReverseEngineering.reverseEngineerViews(connection, schema)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Schema)
def reverseEngineerProcedures(connection, schema):
    return GenericReverseEngineering.reverseEngineerProcedures(connection, schema)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Schema)
def reverseEngineerFunctions(connection, schema):
    return GenericReverseEngineering.reverseEngineerFunctions(connection, schema)

@ModuleInfo.export(grt.INT, grt.classes.db_mgmt_Connection, grt.classes.db_Schema)
def reverseEngineerTriggers(connection, schema):
    return GenericReverseEngineering.reverseEngineerTriggers(connection, schema)
