#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
import re


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 = {}
        self._model = model

        # Create new table if necessary
        if not self.table_exist(self.cursor, self.table_name):
            if not self.history:
                self.cursor.execute('CREATE TABLE "%s" ' \
                        '(id INTEGER PRIMARY KEY)' % \
                        self.table_name)
            else:
                self.cursor.execute('CREATE TABLE "%s" ' \
                        '(__id INTEGER PRIMARY KEY, ' \
                        'id INTEGER)' % self.table_name)

        self._update_definitions()

    @staticmethod
    def table_exist(cursor, table_name):
        cursor.execute("SELECT name FROM sqlite_master " \
                           "WHERE type = 'table' AND name = %s",
                       (table_name,))
        return bool(cursor.fetchone())

    @staticmethod
    def table_rename(cursor, old_name, new_name):
        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 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):
        return True

    @staticmethod
    def sequence_rename(cursor, old_name, new_name):
        pass

    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('PRAGMA table_info("' + self.table_name + '")')
        self._columns = {}
        for _, column, type_, notnull, hasdef, _ in self.cursor.fetchall():
            column = re.sub(r'^\"|\"$', '', column)
            match = re.match(r'(\w+)(\((.*?)\))?', type_)
            if match:
                typname = match.group(1).upper()
                size = match.group(3) and int(match.group(3)) or None
            else:
                typname = type_.upper()
                size = -1
            self._columns[column] = {
                'notnull': notnull,
                'hasdef': hasdef,
                'size': size,
                'typname': typname,
            }

        # Fetch indexes defined for the table
        try:
            self.cursor.execute('PRAGMA index_list("' + self.table_name + '")')
        except IndexError: # There is sometimes IndexError
            self.cursor.execute('PRAGMA index_list("' + self.table_name + '")')
        self._indexes = [l[1] 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):
        logging.getLogger('init').warning(
            'Unable to alter size of column %s ' \
                'of table %s!' % \
                (column_name, self.table_name))

    def alter_type(self, column_name, column_type):
        logging.getLogger('init').warning(
            'Unable to alter type of column %s ' \
                'of table %s!' % \
                (column_name, self.table_name))

    def db_default(self, column_name, value):
        logging.getLogger('init').warning(
            'Unable to set default on column %s ' \
                'of table %s!' % \
                (column_name, self.table_name))

    def add_raw_column(self, column_name, column_type, column_format,
            default_fun=None, field_size=None, migrate=True, string=''):
        if self.column_exist(column_name):
            if not migrate:
                return
            base_type = column_type[0].upper()
            if base_type != self._columns[column_name]['typname']:
                if (self._columns[column_name]['typname'], base_type) in [
                        ('VARCHAR', 'TEXT'),
                        ('TEXT', 'VARCHAR'),
                        ('DATE', 'TIMESTAMP'),
                        ('INTEGER', 'FLOAT'),
                        ]:
                    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]
        default = ''
        from trytond.model import fields
        if column_name in self._model._columns and \
                isinstance(self._model._columns[column_name],
                        (fields.Integer, fields.Float)):
            default = ' DEFAULT 0'
        self.cursor.execute(('ALTER TABLE "%s" ADD COLUMN "%s" %s' + default) %
                       (self.table_name, column_name, column_type))

        if column_format:
            # check if table is non-empty:
            self.cursor.execute('SELECT 1 FROM "%s" limit 1' % self.table_name)
            if self.cursor.fetchone():
                # Populate column with default values:
                default = None
                if default_fun is not None:
                    default = default_fun(self.cursor, 0, {})
                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):
        logging.getLogger('init').warning(
            'Unable to add foreign key on table %s!' % \
            (self.table_name,))

    def drop_fk(self, column_name, table=None):
        logging.getLogger('init').warning(
            'Unable to drop foreign key on table %s!' % \
            (self.table_name,))

    def index_action(self, column_name, action='add', table=None):
        if isinstance(column_name, basestring):
            column_name = [column_name]
        index_name = self.table_name + "_" + '_'.join(column_name) + "_index"

        if action == 'add':
            if 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 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':
            logging.getLogger('init').warning(
                'Unable to set not null on column %s ' \
                    'of table %s!' % \
                    (column_name, self.table_name))
        elif action == 'remove':
            logging.getLogger('init').warning(
                    'Unable to remove not null on column %s ' \
                            'of table %s!' % \
                            (column_name, self.table_name))
        else:
            raise Exception('Not null action not supported!')

    def add_constraint(self, ident, constraint, exception=False):
        logging.getLogger('init').warning(
            'Unable to add constraint on table %s!' % \
            (self.table_name,))

    def drop_constraint(self, ident, exception=False, table=None):
        logging.getLogger('init').warning(
            'Unable to drop constraint on table %s!' % \
            (self.table_name,))

    def drop_column(self, column_name, exception=False):
        logging.getLogger('init').warning(
            'Unable to drop \'%s\' column on table %s!' % \
            (column_name, self.table_name))

    @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)