import functools
import inspect
import itertools
import os
import re
import unittest
from collections.abc import Callable
from contextlib import AbstractContextManager
from threading import Lock
from types import FunctionType
from typing import (
    TYPE_CHECKING,
    Any,
    TypeVar,
)
from unittest.mock import patch

import boto3
import botocore
import responses
from botocore.config import Config
from botocore.handlers import BUILTIN_HANDLERS

import moto.backend_index as backend_index
from moto import settings

from .base_backend import BackendDict
from .botocore_stubber import BotocoreStubber
from .config import DefaultConfig, default_user_config, mock_credentials
from .custom_responses_mock import (
    CallbackResponse,
    get_response_mock,
    not_implemented_callback,
    reset_responses_mock,
)
from .model_instances import reset_model_data

if TYPE_CHECKING:
    from typing_extensions import ParamSpec

    P = ParamSpec("P")


DEFAULT_ACCOUNT_ID = "123456789012"
T = TypeVar("T")


class MockAWS(AbstractContextManager["MockAWS"]):
    _nested_count = 0
    _mocks_active = False
    _mock_init_lock = Lock()

    def __init__(self, config: DefaultConfig | None = None) -> None:
        self._fake_creds = {
            "AWS_ACCESS_KEY_ID": "FOOBARKEY",
            "AWS_SECRET_ACCESS_KEY": "FOOBARSECRET",
        }
        self._orig_creds: dict[str, str | None] = {}
        self._default_session_mock = patch("boto3.DEFAULT_SESSION", None)
        current_user_config = default_user_config.copy()
        current_user_config.update(config or {})
        self._user_config_mock = patch.dict(default_user_config, current_user_config)

    def __call__(
        self, func: "Callable[P, T]", reset: bool = True, remove_data: bool = True
    ) -> "Callable[P, T]":
        if inspect.isclass(func):
            return self._decorate_class(func)
        return self._decorate_callable(func, reset, remove_data)

    def __enter__(self) -> "MockAWS":
        self.start()
        return self

    def __exit__(self, *args: Any) -> None:
        self.stop()

    def start(self, reset: bool = True) -> None:
        with MockAWS._mock_init_lock:
            self._user_config_mock.start()
            if mock_credentials():
                self._mock_env_variables()
            if not self.__class__._mocks_active:
                if default_user_config.get("core", {}).get("reset_boto3_session", True):
                    self._default_session_mock.start()
                self.__class__._mocks_active = True

            self.__class__._nested_count += 1

            if self.__class__._nested_count == 1:
                self._enable_patching(reset=reset)

    def stop(self, remove_data: bool = True) -> None:
        with MockAWS._mock_init_lock:
            self.__class__._nested_count -= 1

            if self.__class__._nested_count < 0:
                raise RuntimeError("Called stop() before start().")

            if mock_credentials():
                self._unmock_env_variables()

            if self.__class__._nested_count == 0:
                if self.__class__._mocks_active:
                    if default_user_config.get("core", {}).get(
                        "reset_boto3_session", True
                    ):
                        self._default_session_mock.stop()
                    self._user_config_mock.stop()
                    self.__class__._mocks_active = False
                self._disable_patching(remove_data)

    def _decorate_callable(
        self, func: "Callable[P, T]", reset: bool, remove_data: bool
    ) -> "Callable[P, T]":
        def wrapper(*args: Any, **kwargs: Any) -> T:
            self.start(reset=reset)
            try:
                result = func(*args, **kwargs)
            finally:
                self.stop(remove_data=remove_data)
            return result

        functools.update_wrapper(wrapper, func)
        wrapper.__wrapped__ = func  # type: ignore[attr-defined]
        return wrapper

    def _decorate_class(self, klass: "Callable[P, T]") -> "Callable[P, T]":
        assert inspect.isclass(klass)  # Keep mypy happy
        direct_methods = get_direct_methods_of(klass)
        defined_classes = {x for x, y in klass.__dict__.items() if inspect.isclass(y)}

        # Get a list of all userdefined superclasses
        superclasses = [
            c for c in klass.__mro__ if c not in [unittest.TestCase, object]
        ]
        # Get a list of all userdefined methods
        supermethods = list(
            itertools.chain(*[get_direct_methods_of(c) for c in superclasses])
        )
        # Check whether the user has overridden the setUp-method
        has_setup_method = (
            ("setUp" in supermethods and unittest.TestCase in klass.__mro__)
            or "setup" in supermethods
            or "setup_method" in supermethods
        )

        for attr in itertools.chain(direct_methods, defined_classes):
            if attr.startswith("_"):
                continue

            attr_value = getattr(klass, attr)
            if not callable(attr_value):
                continue
            if not hasattr(attr_value, "__name__"):
                continue

            # Check if this is a classmethod. If so, skip patching
            if inspect.ismethod(attr_value) and attr_value.__self__ is klass:
                continue

            # Check if this is a staticmethod. If so, skip patching
            for cls in inspect.getmro(klass):
                if attr_value.__name__ not in cls.__dict__:
                    continue
                bound_attr_value = cls.__dict__[attr_value.__name__]
                if not isinstance(bound_attr_value, staticmethod):
                    break
            else:
                # It is a staticmethod, skip patching
                continue

            try:
                # Special case for UnitTests-class
                is_test_method = attr.startswith(unittest.TestLoader.testMethodPrefix)
                should_reset = False
                should_remove_data = False
                if attr in ["setUp", "setup_method"]:
                    should_reset = True
                elif not has_setup_method and is_test_method:
                    should_reset = True
                    should_remove_data = True
                else:
                    # Method is unrelated to the test setup
                    # Method is a test, but was already reset while executing the setUp-method
                    pass
                kwargs = {"reset": should_reset, "remove_data": should_remove_data}
                setattr(klass, attr, self(attr_value, **kwargs))
            except TypeError:
                # Sometimes we can't set this for built-in types
                continue
        return klass

    def _mock_env_variables(self) -> None:
        # "Mock" the AWS credentials as they can't be mocked in Botocore currently
        for k, v in self._fake_creds.items():
            self._orig_creds[k] = os.environ.get(k, None)
            os.environ[k] = v

    def _unmock_env_variables(self) -> None:
        for k, v in self._orig_creds.items():
            if v:
                os.environ[k] = v
            else:
                del os.environ[k]

    def reset(self) -> None:
        BackendDict.reset()
        reset_responses_mock(responses_mock)

    def _enable_patching(self, reset: bool = True) -> None:
        botocore_stubber.enabled = True
        if reset:
            self.reset()
        responses_mock.start()

        for method in RESPONSES_METHODS:
            for _, pattern in backend_index.backend_url_patterns:
                responses_mock.add(
                    CallbackResponse(
                        method=method,
                        url=pattern,
                        callback=botocore_stubber.process_request,
                    )
                )
            responses_mock.add(
                CallbackResponse(
                    method=method,
                    url=re.compile(r"https?://.+\.amazonaws.com/.*"),
                    callback=not_implemented_callback,
                )
            )

    def _disable_patching(self, remove_data: bool) -> None:
        botocore_stubber.enabled = False
        if remove_data:
            self.reset()
            reset_model_data()

        responses_mock.stop()


def get_direct_methods_of(klass: object) -> set[str]:
    return {
        x
        for x, y in klass.__dict__.items()
        if isinstance(y, (FunctionType, classmethod, staticmethod))
    }


RESPONSES_METHODS = [
    responses.GET,
    responses.DELETE,
    responses.HEAD,
    responses.OPTIONS,
    responses.PATCH,
    responses.POST,
    responses.PUT,
]

responses_mock = get_response_mock()

BOTOCORE_HTTP_METHODS = ["GET", "DELETE", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]


botocore_stubber = BotocoreStubber()
BUILTIN_HANDLERS.append(("before-send", botocore_stubber))


def patch_client(client: botocore.client.BaseClient) -> None:
    """
    Explicitly patch a boto3-client
    """
    """
    Adding the botocore_stubber to the BUILTIN_HANDLERS, as above, will mock everything as long as the import ordering is correct
     - user:   start mock_aws decorator
     - system: imports core.model
     - system: adds the stubber to the BUILTIN_HANDLERS
     - user:   create a boto3 client - which will use the BUILTIN_HANDLERS

    But, if for whatever reason the imports are wrong and the client is created first, it doesn't know about our stub yet
    This method can be used to tell a client that it needs to be mocked, and append the botocore_stubber after creation
    :param client:
    :return:
    """
    if isinstance(client, botocore.client.BaseClient):
        # Check if our event handler was already registered
        try:
            event_emitter = client._ruleset_resolver._event_emitter._emitter  # type: ignore[attr-defined]
            all_handlers = event_emitter._handlers._root["children"]
            handler_trie = list(all_handlers["before-send"].values())[1]
            handlers_list = handler_trie.first + handler_trie.middle + handler_trie.last
            if botocore_stubber in handlers_list:
                # No need to patch - this client already has the botocore_stubber registered
                return
        except:  # noqa: E722 Do not use bare except
            # Because we're accessing all kinds of private methods, the API may change and newer versions of botocore may throw an exception
            # One of our tests will fail if this happens (test_patch_can_be_called_on_a_mocked_client)
            # If this happens for a user, just continue and hope for the best
            #  - in 99% of the cases there are no duplicate event handlers, so it doesn't matter if the check fails
            pass

        client.meta.events.register("before-send", botocore_stubber)  # type: ignore[arg-type]
    else:
        raise Exception(f"Argument {client} should be of type boto3.client")


def patch_resource(resource: Any) -> None:
    """
    Explicitly patch a boto3-resource
    """
    if hasattr(resource, "meta") and isinstance(
        resource.meta, boto3.resources.factory.ResourceMeta
    ):
        patch_client(resource.meta.client)
    else:
        raise Exception(f"Argument {resource} should be of type boto3.resource")


def override_responses_real_send(user_mock: responses.RequestsMock | None) -> None:
    """
    Moto creates it's own Responses-object responsible for intercepting AWS requests
    If a custom Responses-object is created by the user, Moto will hijack any of the pass-thru's set

    Call this method to ensure any requests unknown to Moto are passed through the custom Responses-object.

    Set the user_mock argument to None to reset this behaviour.

    Note that this is only supported from Responses>=0.24.0
    """
    if user_mock is None:
        responses_mock._real_send = responses._real_send
    else:
        responses_mock._real_send = user_mock.unbound_on_send()


class ServerModeMockAWS(MockAWS):
    _RESET_IN_PROGRESS = False

    def __init__(self, *args: Any, **kwargs: Any):
        self._test_server_mode_endpoint = settings.test_server_mode_endpoint()
        super().__init__(*args, **kwargs)

    def reset(self) -> None:
        call_reset_api = os.environ.get("MOTO_CALL_RESET_API")
        if not call_reset_api or call_reset_api.lower() != "false":
            if not ServerModeMockAWS._RESET_IN_PROGRESS:
                ServerModeMockAWS._RESET_IN_PROGRESS = True
                import requests

                requests.post(f"{self._test_server_mode_endpoint}/moto-api/reset")
                ServerModeMockAWS._RESET_IN_PROGRESS = False

    def _enable_patching(self, reset: bool = True) -> None:
        if self.__class__._nested_count == 1 and reset:
            # Just started
            self.reset()

        from boto3 import client as real_boto3_client
        from boto3 import resource as real_boto3_resource

        def fake_boto3_client(*args: Any, **kwargs: Any) -> botocore.client.BaseClient:
            region = self._get_region(*args, **kwargs)
            if region:
                if "config" in kwargs:
                    user_agent = kwargs["config"].__dict__.get("user_agent_extra") or ""
                    kwargs["config"].__dict__["user_agent_extra"] = (
                        f"{user_agent} region/{region}"
                    )
                else:
                    config = Config(user_agent_extra="region/" + region)
                    kwargs["config"] = config
            if "endpoint_url" not in kwargs:
                kwargs["endpoint_url"] = self._test_server_mode_endpoint
            return real_boto3_client(*args, **kwargs)

        def fake_boto3_resource(*args: Any, **kwargs: Any) -> Any:
            if "endpoint_url" not in kwargs:
                kwargs["endpoint_url"] = self._test_server_mode_endpoint
            return real_boto3_resource(*args, **kwargs)

        self._client_patcher = patch("boto3.client", fake_boto3_client)
        self._resource_patcher = patch("boto3.resource", fake_boto3_resource)
        self._client_patcher.start()
        self._resource_patcher.start()

    def _get_region(self, *args: Any, **kwargs: Any) -> str | None:
        if "region_name" in kwargs:
            return kwargs["region_name"]
        if type(args) is tuple and len(args) == 2:
            _, region = args
            return region
        return None

    def _disable_patching(self, remove_data: bool) -> None:
        if self._client_patcher:
            self._client_patcher.stop()
            self._resource_patcher.stop()
        if remove_data:
            self.reset()


class ProxyModeMockAWS(MockAWS):
    _RESET_IN_PROGRESS = False

    def __init__(self, *args: Any, **kwargs: Any):
        self._test_proxy_mode_endpoint = settings.test_proxy_mode_endpoint()
        super().__init__(*args, **kwargs)

    def reset(self) -> None:
        call_reset_api = os.environ.get("MOTO_CALL_RESET_API")
        if not call_reset_api or call_reset_api.lower() != "false":
            if not ProxyModeMockAWS._RESET_IN_PROGRESS:
                ProxyModeMockAWS._RESET_IN_PROGRESS = True
                import requests

                requests.post(f"{self._test_proxy_mode_endpoint}/moto-api/reset")
                ProxyModeMockAWS._RESET_IN_PROGRESS = False

    def _enable_patching(self, reset: bool = True) -> None:
        if self.__class__._nested_count == 1 and reset:
            # Just started
            self.reset()

        from boto3 import client as real_boto3_client
        from boto3 import resource as real_boto3_resource

        def fake_boto3_client(*args: Any, **kwargs: Any) -> botocore.client.BaseClient:
            kwargs["verify"] = False
            proxy_endpoint = (
                f"http://localhost:{os.environ.get('MOTO_PROXY_PORT', 5005)}"
            )
            proxies = {"http": proxy_endpoint, "https": proxy_endpoint}
            if "config" in kwargs:
                kwargs["config"].__dict__["proxies"] = proxies
            else:
                config = Config(proxies=proxies)
                kwargs["config"] = config

            return real_boto3_client(*args, **kwargs)

        def fake_boto3_resource(*args: Any, **kwargs: Any) -> Any:
            kwargs["verify"] = False
            proxy_endpoint = (
                f"http://localhost:{os.environ.get('MOTO_PROXY_PORT', 5005)}"
            )
            proxies = {"http": proxy_endpoint, "https": proxy_endpoint}
            if "config" in kwargs:
                kwargs["config"].__dict__["proxies"] = proxies
            else:
                config = Config(proxies=proxies)
                kwargs["config"] = config
            return real_boto3_resource(*args, **kwargs)

        self._client_patcher = patch("boto3.client", fake_boto3_client)
        self._resource_patcher = patch("boto3.resource", fake_boto3_resource)
        self._client_patcher.start()
        self._resource_patcher.start()

    def _disable_patching(self, remove_data: bool) -> None:
        if self._client_patcher:
            self._client_patcher.stop()
            self._resource_patcher.stop()
