import re
from .base import SQLAdapter
from ..utils import split_uri_args
from . import adapters, with_connection


@adapters.register_for("mysql")
class MySQL(SQLAdapter):
    dbengine = "mysql"
    drivers = ("MySQLdb", "pymysql", "mysqlconnector")
    commit_on_alter_table = True
    support_distributed_transaction = True

    REGEX_URI = (
        "^(?P<user>[^:@]+)(:(?P<password>[^@]*))?"
        r"@(?P<host>[^:/]*|\[[^\]]+\])(:(?P<port>\d+))?"
        "/(?P<db>[^?]+)"
        r"(\?(?P<uriargs>.*))?$"
    )  # set_encoding and unix_socket

    def _initialize_(self):
        super(MySQL, self)._initialize_()
        ruri = self.uri.split("://", 1)[1]
        m = re.match(self.REGEX_URI, ruri)
        if not m:
            raise SyntaxError("Invalid URI string in DAL")
        user = self.credential_decoder(m.group("user"))
        password = self.credential_decoder(m.group("password"))
        host = m.group("host")
        uriargs = m.group("uriargs")
        if uriargs:
            uri_args = split_uri_args(uriargs, need_equal=True)
            charset = uri_args.get("set_encoding") or "utf8"
            socket = uri_args.get("unix_socket")
        else:
            charset = "utf8"
            socket = None
        # NOTE:
        # MySQLdb (see http://mysql-python.sourceforge.net/MySQLdb.html)
        # use UNIX sockets and named pipes by default if no host is given
        # or host is 'localhost'; as opposed to
        # pymysql (see https://pymysql.readthedocs.io/en/latest/modules/connections.html)
        # or mysqlconnector (see https://dev.mysql.com/doc/connectors/en/connector-python-connectargs.html)
        # driver, where you have to specify the socket explicitly.
        if not host and not socket:
            raise SyntaxError("Host or UNIX socket name required")
        db = m.group("db")
        port = int(m.group("port") or "3306")
        self.driver_args.update(user=user, db=db, charset=charset)
        if password is not None:
            self.driver_args["passwd"] = password
        if socket:
            self.driver_args["unix_socket"] = socket
        else:
            self.driver_args.update(host=host, port=port)

    def connector(self):
        cursor_buffered = self.driver_args.get("cursor_buffered")
        if cursor_buffered:
            del self.driver_args["cursor_buffered"]
        conn = self.driver.connect(**self.driver_args)
        if cursor_buffered:
            conn.cursor = lambda conn=conn: conn.cursor(buffered=True)
        return conn

    def after_connection(self):
        self.execute("SET FOREIGN_KEY_CHECKS=1;")
        self.execute("SET sql_mode='NO_BACKSLASH_ESCAPES';")

    def distributed_transaction_begin(self, key):
        self.execute("XA START;")

    @with_connection
    def prepare(self, key):
        self.execute("XA END;")
        self.execute("XA PREPARE;")

    @with_connection
    def commit_prepared(self, key):
        self.execute("XA COMMIT;")

    @with_connection
    def rollback_prepared(self, key):
        self.execute("XA ROLLBACK;")


@adapters.register_for("cubrid")
class Cubrid(MySQL):
    dbengine = "cubrid"
    drivers = ("cubriddb",)

    def _initialize_(self):
        super(Cubrid, self)._initialize_()
        del self.driver_args["charset"]