import os
import sqlite3
import sqlite3.dbapi2
import sys

import wrapt

from ddtrace import config
from ddtrace.appsec._iast._metrics import _set_metric_iast_instrumented_sink
from ddtrace.appsec._iast.constants import VULN_SQL_INJECTION
from ddtrace.contrib.dbapi import FetchTracedCursor
from ddtrace.contrib.dbapi import TracedConnection
from ddtrace.contrib.dbapi import TracedCursor
from ddtrace.ext import db
from ddtrace.internal.schema import schematize_database_operation
from ddtrace.internal.schema import schematize_service_name
from ddtrace.internal.utils.formats import asbool
from ddtrace.pin import Pin
from ddtrace.settings.asm import config as asm_config


# Original connect method
_connect = sqlite3.connect

config._add(
    "sqlite",
    dict(
        _default_service=schematize_service_name("sqlite"),
        _dbapi_span_name_prefix="sqlite",
        _dbapi_span_operation_name=schematize_database_operation("sqlite.query", database_provider="sqlite"),
        trace_fetch_methods=asbool(os.getenv("DD_SQLITE_TRACE_FETCH_METHODS", default=False)),
    ),
)


def get_version():
    # type: () -> str
    return sqlite3.sqlite_version


def patch():
    if getattr(sqlite3, "_datadog_patch", False):
        return
    sqlite3._datadog_patch = True
    wrapped = wrapt.FunctionWrapper(_connect, traced_connect)

    sqlite3.connect = wrapped
    sqlite3.dbapi2.connect = wrapped

    if asm_config._iast_enabled:
        _set_metric_iast_instrumented_sink(VULN_SQL_INJECTION)


def unpatch():
    if getattr(sqlite3, "_datadog_patch", False):
        sqlite3._datadog_patch = False
    sqlite3.connect = _connect
    sqlite3.dbapi2.connect = _connect


def traced_connect(func, _, args, kwargs):
    conn = func(*args, **kwargs)
    return patch_conn(conn)


def patch_conn(conn):
    wrapped = TracedSQLite(conn)
    Pin(tags={db.SYSTEM: "sqlite"}).onto(wrapped)
    return wrapped


class TracedSQLiteCursor(TracedCursor):
    def executemany(self, *args, **kwargs):
        # DEV: SQLite3 Cursor.execute always returns back the cursor instance
        super(TracedSQLiteCursor, self).executemany(*args, **kwargs)
        return self

    def execute(self, *args, **kwargs):
        # DEV: SQLite3 Cursor.execute always returns back the cursor instance
        super(TracedSQLiteCursor, self).execute(*args, **kwargs)
        return self


class TracedSQLiteFetchCursor(TracedSQLiteCursor, FetchTracedCursor):
    pass


class TracedSQLite(TracedConnection):
    def __init__(self, conn, pin=None, cursor_cls=None):
        if not cursor_cls:
            # Do not trace `fetch*` methods by default
            cursor_cls = TracedSQLiteFetchCursor if config.sqlite.trace_fetch_methods else TracedSQLiteCursor

            super(TracedSQLite, self).__init__(conn, pin=pin, cfg=config.sqlite, cursor_cls=cursor_cls)

    def execute(self, *args, **kwargs):
        # sqlite has a few extra sugar functions
        return self.cursor().execute(*args, **kwargs)

    # backup was added in Python 3.7
    if sys.version_info >= (3, 7, 0):

        def backup(self, target, *args, **kwargs):
            # sqlite3 checks the type of `target`, it cannot be a wrapped connection
            # https://github.com/python/cpython/blob/4652093e1b816b78e9a585d671a807ce66427417/Modules/_sqlite/connection.c#L1897-L1899
            if isinstance(target, TracedConnection):
                target = target.__wrapped__
            return self.__wrapped__.backup(target, *args, **kwargs)
