# connectors/pyodbc.py
# Copyright (C) 2005-2020 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php

import re

from . import Connector
from .. import util


class PyODBCConnector(Connector):
    driver = "pyodbc"

    # this is no longer False for pyodbc in general
    supports_sane_rowcount_returning = True
    supports_sane_multi_rowcount = False

    supports_unicode_statements = True
    supports_unicode_binds = True

    supports_native_decimal = True
    default_paramstyle = "named"

    # for non-DSN connections, this *may* be used to
    # hold the desired driver name
    pyodbc_driver_name = None

    def __init__(self, supports_unicode_binds=None, **kw):
        super(PyODBCConnector, self).__init__(**kw)
        if supports_unicode_binds is not None:
            self.supports_unicode_binds = supports_unicode_binds

    @classmethod
    def dbapi(cls):
        return __import__("pyodbc")

    def create_connect_args(self, url):
        opts = url.translate_connect_args(username="user")
        opts.update(url.query)

        keys = opts

        query = url.query

        connect_args = {}
        for param in ("ansi", "unicode_results", "autocommit"):
            if param in keys:
                connect_args[param] = util.asbool(keys.pop(param))

        if "odbc_connect" in keys:
            connectors = [util.unquote_plus(keys.pop("odbc_connect"))]
        else:

            def check_quote(token):
                if ";" in str(token):
                    token = "{%s}" % token.replace("}", "}}")
                return token

            keys = dict((k, check_quote(v)) for k, v in keys.items())

            dsn_connection = "dsn" in keys or (
                "host" in keys and "database" not in keys
            )
            if dsn_connection:
                connectors = [
                    "dsn=%s" % (keys.pop("host", "") or keys.pop("dsn", ""))
                ]
            else:
                port = ""
                if "port" in keys and "port" not in query:
                    port = ",%d" % int(keys.pop("port"))

                connectors = []
                driver = keys.pop("driver", self.pyodbc_driver_name)
                if driver is None and keys:
                    # note if keys is empty, this is a totally blank URL
                    util.warn(
                        "No driver name specified; "
                        "this is expected by PyODBC when using "
                        "DSN-less connections"
                    )
                else:
                    connectors.append("DRIVER={%s}" % driver)

                connectors.extend(
                    [
                        "Server=%s%s" % (keys.pop("host", ""), port),
                        "Database=%s" % keys.pop("database", ""),
                    ]
                )

            user = keys.pop("user", None)
            if user:
                connectors.append("UID=%s" % user)
                pwd = keys.pop("password", "")
                if pwd:
                    connectors.append("PWD=%s" % pwd)
            else:
                authentication = keys.pop("authentication", None)
                if authentication:
                    connectors.append("Authentication=%s" % authentication)
                else:
                    connectors.append("Trusted_Connection=Yes")

            # if set to 'Yes', the ODBC layer will try to automagically
            # convert textual data from your database encoding to your
            # client encoding.  This should obviously be set to 'No' if
            # you query a cp1253 encoded database from a latin1 client...
            if "odbc_autotranslate" in keys:
                connectors.append(
                    "AutoTranslate=%s" % keys.pop("odbc_autotranslate")
                )

            connectors.extend(["%s=%s" % (k, v) for k, v in keys.items()])

        return [[";".join(connectors)], connect_args]

    def is_disconnect(self, e, connection, cursor):
        if isinstance(e, self.dbapi.ProgrammingError):
            return "The cursor's connection has been closed." in str(
                e
            ) or "Attempt to use a closed connection." in str(e)
        else:
            return False

    # def initialize(self, connection):
    #   super(PyODBCConnector, self).initialize(connection)

    def _dbapi_version(self):
        if not self.dbapi:
            return ()
        return self._parse_dbapi_version(self.dbapi.version)

    def _parse_dbapi_version(self, vers):
        m = re.match(r"(?:py.*-)?([\d\.]+)(?:-(\w+))?", vers)
        if not m:
            return ()
        vers = tuple([int(x) for x in m.group(1).split(".")])
        if m.group(2):
            vers += (m.group(2),)
        return vers

    def _get_server_version_info(self, connection, allow_chars=True):
        # NOTE: this function is not reliable, particularly when
        # freetds is in use.   Implement database-specific server version
        # queries.
        dbapi_con = connection.connection
        version = []
        r = re.compile(r"[.\-]")
        for n in r.split(dbapi_con.getinfo(self.dbapi.SQL_DBMS_VER)):
            try:
                version.append(int(n))
            except ValueError:
                if allow_chars:
                    version.append(n)
        return tuple(version)

    def set_isolation_level(self, connection, level):
        # adjust for ConnectionFairy being present
        # allows attribute set e.g. "connection.autocommit = True"
        # to work properly
        if hasattr(connection, "connection"):
            connection = connection.connection

        if level == "AUTOCOMMIT":
            connection.autocommit = True
        else:
            connection.autocommit = False
            super(PyODBCConnector, self).set_isolation_level(connection, level)
