#This file is part of Tryton.  The COPYRIGHT file at the top level of
#this repository contains the full copyright notices and license terms.

from trytond.backend.table import TableHandlerInterface
import logging


class TableHandler(TableHandlerInterface):

    def __init__(self, cursor, model, module_name=None, history=False):
        super(TableHandler, self).__init__(cursor, model,
                module_name=module_name, history=history)
        self._columns = {}
        self._constraints = []
        self._fk_deltypes = {}
        self._indexes = []
        self._field2module = {}

        # Create sequence if necessary
        if not self.sequence_exist(self.cursor, self.sequence_name):
            self.cursor.execute('CREATE SEQUENCE "%s"' % self.sequence_name)

        # Create new table if necessary
        if not self.table_exist(self.cursor, self.table_name):
            self.cursor.execute('CREATE TABLE "%s" ()' % self.table_name)

        self.cursor.execute('COMMENT ON TABLE "%s" IS \'%s\'' % 
                (self.table_name, model._description.replace("'", "''")))

        self._update_definitions()
        if 'id' not in self._columns:
            if not self.history:
                self.cursor.execute('ALTER TABLE "%s" ' \
                        'ADD COLUMN id INTEGER ' \
                            'DEFAULT nextval(\'"%s"\') NOT NULL' % \
                            (self.table_name, self.sequence_name))
                self.cursor.execute('ALTER TABLE "%s" ' \
                        'ADD PRIMARY KEY(id)' % self.table_name)
            else:
                self.cursor.execute('ALTER TABLE "%s" ' \
                        'ADD COLUMN id INTEGER' % self.table_name)
            self._update_definitions()
        if self.history and not '__id' in self._columns:
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'ADD COLUMN __id INTEGER ' \
                        'DEFAULT nextval(\'"%s"\') NOT NULL' % \
                        (self.table_name, self.sequence_name))
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'ADD PRIMARY KEY(__id)' % self.table_name)
        if self.history:
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'ALTER __id SET DEFAULT nextval(\'"%s"\')' % (self.table_name,
                        self.sequence_name))
        else:
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'ALTER id SET DEFAULT nextval(\'"%s"\')' % (self.table_name,
                        self.sequence_name))
        self._update_definitions()

    @staticmethod
    def table_exist(cursor, table_name):
        cursor.execute("SELECT relname FROM pg_class " \
                           "WHERE relkind = 'r' AND relname = %s",
                       (table_name,))
        return bool(cursor.rowcount)

    @staticmethod
    def table_rename(cursor, old_name, new_name):
        #Rename table
        if TableHandler.table_exist(cursor, old_name) and \
                not TableHandler.table_exist(cursor, new_name):
            cursor.execute('ALTER TABLE "%s" RENAME TO "%s"' % \
                    (old_name, new_name))
        # Rename sequence
        old_sequence = old_name + '_id_seq'
        new_sequence = new_name + '_id_seq'
        TableHandler.sequence_rename(cursor, old_sequence, new_sequence)
        #Rename history table
        old_history = old_name + "__history"
        new_history = new_name + "__history"
        if TableHandler.table_exist(cursor, old_history) and \
                not TableHandler.table_exist(cursor, new_history):
            cursor.execute('ALTER TABLE "%s" RENAME TO "%s"' % \
                    (old_history, new_history))

    @staticmethod
    def sequence_exist(cursor, sequence_name):
        cursor.execute('SELECT relname FROM pg_class ' \
                'WHERE relkind = \'S\' and relname = %s', (sequence_name,))
        return bool(cursor.rowcount)

    @staticmethod
    def sequence_rename(cursor, old_name, new_name):
        if TableHandler.sequence_exist(cursor, old_name) and \
                not TableHandler.sequence_exist(cursor, new_name):
            cursor.execute('ALTER TABLE "%s" RENAME TO "%s"' % \
                    (old_name, new_name))

    def column_exist(self, column_name):
        return column_name in self._columns

    def column_rename(self, old_name, new_name, exception=False):
        if self.column_exist(old_name) and \
                not self.column_exist(new_name):
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'RENAME COLUMN "%s" TO "%s"' %
                    (self.table_name, old_name, new_name))
        elif exception and self.column_exist(new_name):
            raise Exception('Unable to rename column %s.%s to %s.%s: ' \
                    '%s.%s already exist!' % \
                    (self.table_name, old_name, self.table_name, new_name,
                     self.table_name, new_name))

    def _update_definitions(self):
        # Fetch columns definitions from the table
        self.cursor.execute("SELECT at.attname, at.attlen, "\
                         "at.atttypmod, at.attnotnull, at.atthasdef, "\
                         "ty.typname, "\
                         "CASE WHEN at.attlen = -1 "\
                           "THEN at.atttypmod-4 "\
                           "ELSE at.attlen END as size "\
                       "FROM pg_class cl "\
                         "JOIN pg_attribute at on (cl.oid = at.attrelid) "\
                         "JOIN pg_type ty on (at.atttypid = ty.oid) "\
                       "WHERE cl.relname = %s AND at.attnum > 0",
                       (self.table_name,))
        self._columns = {}
        for line in self.cursor.fetchall():
            column, length, typmod, notnull, hasdef, typname, size = line
            self._columns[column] = {
                "length": length,
                "typmod": typmod,
                "notnull": notnull ,
                "hasdef": hasdef,
                "size": size,
                "typname": typname}

        # fetch constraints for the table
        self.cursor.execute("SELECT co.contype, co.confdeltype, at.attname, "\
                         "cl2.relname, co.conname "\
                       "FROM pg_constraint co "\
                         "LEFT JOIN pg_class cl ON (co.conrelid = cl.oid) "\
                         "LEFT JOIN pg_class cl2 ON (co.confrelid = cl2.oid) "\
                         "LEFT JOIN pg_attribute at ON " \
                            "(co.conkey[1] = at.attnum) "\
                       "WHERE cl.relname = %s AND at.attrelid = cl.oid",
                       (self.table_name,))
        self._constraints = []
        self._fk_deltypes = {}
        for line in self.cursor.fetchall():
            contype, confdeltype, column, ref, conname = line
            if contype == 'f':
                self._fk_deltypes[column] = confdeltype
            if conname not in self._constraints:
                self._constraints.append(conname)

        # Fetch indexes defined for the table
        self.cursor.execute("SELECT cl2.relname "\
                       "FROM pg_index ind "\
                         "JOIN pg_class cl on (cl.oid = ind.indrelid) "\
                         "JOIN pg_class cl2 on (cl2.oid = ind.indexrelid) "\
                       "WHERE cl.relname = %s",
                       (self.table_name,))
        self._indexes = [l[0] for l in self.cursor.fetchall()]

        # Keep track of which module created each field
        self._field2module = {}
        if self.object_name is not None:
            self.cursor.execute('SELECT f.name, f.module '\
                           'FROM ir_model_field f '\
                             'JOIN ir_model m on (f.model=m.id) '\
                           'WHERE m.model = %s',
                           (self.object_name,)
                           )
            for line in self.cursor.fetchall():
                self._field2module[line[0]] = line[1]

    def alter_size(self, column_name, column_type):

        self.cursor.execute("ALTER TABLE \"%s\" " \
                       "RENAME COLUMN \"%s\" " \
                       "TO _temp_change_size" % \
                       (self.table_name, column_name))
        self.cursor.execute("ALTER TABLE \"%s\" " \
                       "ADD COLUMN \"%s\" %s" % \
                       (self.table_name, column_name, column_type))
        self.cursor.execute("UPDATE \"%s\" " \
                       "SET \"%s\" = _temp_change_size::%s" % \
                       (self.table_name, column_name, column_type))
        self.cursor.execute("ALTER TABLE \"%s\" " \
                       "DROP COLUMN _temp_change_size" % \
                       (self.table_name,))
        self._update_definitions()

    def alter_type(self, column_name, column_type):
        self.cursor.execute('ALTER TABLE "' + self.table_name + '" ' \
                'ALTER "' + column_name + '" TYPE ' + column_type)
        self._update_definitions()

    def db_default(self, column_name, value):
        self.cursor.execute('ALTER TABLE "' + self.table_name + '" ' \
                'ALTER COLUMN "' + column_name + '" SET DEFAULT %s',
                (value,))

    def add_raw_column(self, column_name, column_type, column_format,
            default_fun=None, field_size=None, migrate=True, string=''):
        def comment():
            self.cursor.execute('COMMENT ON COLUMN "%s"."%s" IS \'%s\'' %
                    (self.table_name, column_name, string.replace("'", "''")))
        if self.column_exist(column_name):
            if (column_name in ('create_date', 'write_date')
                    and column_type[1].lower() != 'timestamp(6)'):
                #Migrate dates from timestamp(0) to timestamp
                self.cursor.execute('ALTER TABLE "' + self.table_name + '" ' \
                        'ALTER COLUMN "' + column_name + '" TYPE timestamp')
            comment()
            if not migrate:
                return
            base_type = column_type[0].lower()
            if base_type != self._columns[column_name]['typname']:
                if (self._columns[column_name]['typname'], base_type) in [
                        ('varchar', 'text'),
                        ('text', 'varchar'),
                        ('date', 'timestamp'),
                        ('int4', 'float8'),
                        ]:
                    self.alter_type(column_name, base_type)
                else:
                    logging.getLogger('init').warning(
                        'Unable to migrate column %s on table %s ' \
                                'from %s to %s.' % \
                        (column_name, self.table_name,
                            self._columns[column_name]['typname'], base_type))

            if base_type == 'varchar' \
                    and self._columns[column_name]['typname'] == 'varchar':
                # Migrate size
                if field_size == None:
                    if self._columns[column_name]['size'] > 0:
                        self.alter_size(column_name, base_type)
                elif self._columns[column_name]['size'] == field_size:
                    pass
                elif self._columns[column_name]['size'] > 0 and \
                        self._columns[column_name]['size'] < field_size:
                    self.alter_size(column_name, column_type[1])
                else:
                    logging.getLogger('init').warning(
                        'Unable to migrate column %s on table %s ' \
                                'from varchar(%s) to varchar(%s).' % \
                        (column_name, self.table_name,
                         self._columns[column_name]['size'] > 0 and \
                             self._columns[column_name]['size'] or "",
                         field_size))
            return

        column_type = column_type[1]
        self.cursor.execute('ALTER TABLE "%s" ADD COLUMN "%s" %s' %
                       (self.table_name, column_name, column_type))
        comment()

        if column_format:
            # check if table is non-empty:
            self.cursor.execute('SELECT 1 FROM "%s" limit 1' % self.table_name)
            if self.cursor.rowcount:
                # Populate column with default values:
                default = None
                if default_fun is not None:
                    default = default_fun()
                self.cursor.execute('UPDATE "' + self.table_name + '" '\
                                    'SET "' + column_name + '" = %s',
                                    (column_format(default),))

        self._update_definitions()

    def add_fk(self, column_name, reference, on_delete=None):
        on_delete_code = {
            'RESTRICT': 'r',
            'NO ACTION': 'a',
            'CASCADE': 'c',
            'SET NULL': 'n',
            'SET DEFAULT': 'd',
            }
        if on_delete is not None :
            on_delete = on_delete.upper()
            if on_delete not in on_delete_code:
                raise Exception('On delete action not supported!')
        else:
            on_delete = 'SET NULL'
        code = on_delete_code[on_delete]

        self.cursor.execute('SELECT conname FROM pg_constraint ' \
                'WHERE conname = %s',
                (self.table_name + '_' + column_name + '_fkey',))
        add = False
        if not self.cursor.rowcount:
            add = True
        elif self._fk_deltypes.get(column_name) != code:
            self.drop_fk(column_name)
            add = True
        if add:
            self.cursor.execute('ALTER TABLE "' + self.table_name + '" ' \
                    'ADD FOREIGN KEY ("' + column_name + '") ' \
                        'REFERENCES "' + reference + '" ' \
                        'ON DELETE ' + on_delete)
        self._update_definitions()

    def drop_fk(self, column_name, table=None):
        self.drop_constraint(column_name + '_fkey', table=table)

    def index_action(self, column_name, action='add', table=None):
        if isinstance(column_name, basestring):
            column_name = [column_name]
        index_name = (table or self.table_name) + "_" + '_'.join(column_name) \
                + "_index"
        if self._indexes:
            test_index_name = index_name[:max(map(len, self._indexes))]
        else:
            test_index_name = index_name

        if action == 'add':
            if test_index_name in self._indexes:
                return
            self.cursor.execute('CREATE INDEX "' + index_name + '" ' \
                               'ON "' + self.table_name + '" ( ' + \
                               ','.join(['"' + x + '"' for x in column_name]) +\
                               ')')
            self._update_definitions()
        elif action == 'remove':
            if len(column_name) == 1:
                if self._field2module.get(column_name[0], self.module_name) \
                        != self.module_name:
                    return

            if test_index_name in self._indexes:
                self.cursor.execute('DROP INDEX "%s" ' % (index_name,))
                self._update_definitions()
        else:
            raise Exception('Index action not supported!')

    def not_null_action(self, column_name, action='add'):
        if not self.column_exist(column_name):
            return

        if action == 'add':
            if self._columns[column_name]['notnull']:
                return
            self.cursor.execute('SELECT id FROM "%s" ' \
                               'WHERE "%s" IS NULL' % \
                               (self.table_name, column_name))
            if not self.cursor.rowcount:
                self.cursor.execute('ALTER TABLE "' + self.table_name + '" ' \
                                   'ALTER COLUMN "' + column_name + '" ' \
                                   "SET NOT NULL")
                self._update_definitions()
            else:
                logging.getLogger('init').warning(
                    'Unable to set column %s ' \
                        'of table %s not null !\n'\
                        'Try to re-run: ' \
                        'trytond.py --update=module\n' \
                        'If it doesn\'t work, update records ' \
                        'and execute manually:\n' \
                        'ALTER TABLE "%s" ALTER COLUMN "%s" SET NOT NULL' %
                        (column_name, self.table_name, self.table_name,
                            column_name))
        elif action == 'remove':
            if not self._columns[column_name]['notnull']:
                return
            if self._field2module.get(column_name, self.module_name) \
                    != self.module_name:
                return
            self.cursor.execute('ALTER TABLE "%s" ' \
                               'ALTER COLUMN "%s" DROP NOT NULL' %
                           (self.table_name, column_name))
            self._update_definitions()
        else:
            raise Exception('Not null action not supported!')

    def add_constraint(self, ident, constraint, exception=False):
        ident = self.table_name + "_" + ident
        if ident in self._constraints:
            # This constrain already exist
            return
        try:
            self.cursor.execute('ALTER TABLE "%s" ' \
                           'ADD CONSTRAINT "%s" %s' % \
                           (self.table_name, ident, constraint,))
        except Exception:
            if exception:
                raise
            logging.getLogger('init').warning(
                'unable to add \'%s\' constraint on table %s !\n' \
                'If you want to have it, you should update the records ' \
                'and execute manually:\n'\
                'ALTER table "%s" ADD CONSTRAINT "%s" %s' % \
                (constraint, self.table_name, self.table_name,
                 ident, constraint,))
        self._update_definitions()

    def drop_constraint(self, ident, exception=False, table=None):
        ident = (table or self.table_name) + "_" + ident
        if ident not in self._constraints:
            return
        try:
            self.cursor.execute('ALTER TABLE "%s" ' \
                    'DROP CONSTRAINT "%s"' % \
                    (self.table_name, ident))
        except Exception:
            if exception:
                raise
            logging.getLogger('init').warning(
                'unable to drop \'%s\' constraint on table %s!' % \
                (ident, self.table_name))
        self._update_definitions()

    def drop_column(self, column_name, exception=False):
        if not self.column_exist(column_name):
            return
        try:
            self.cursor.execute(
                'ALTER TABLE "%s" DROP COLUMN "%s"' %
                (self.table_name, column_name))

        except Exception:
            if exception:
                raise
            logging.getLogger('init').warning(
                'unable to drop \'%s\' column on table %s!' % \
                (column_name, self.table_name))
        self._update_definitions()

    @staticmethod
    def drop_table(cursor, model, table, cascade=False):
        cursor.execute('DELETE from ir_model_data where '\
                           'model = \'%s\'' % model)

        query = 'DROP TABLE "%s"' % table
        if cascade:
            query = query + ' CASCADE'
        cursor.execute(query)
