# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.

import argparse
import asyncio
import concurrent.futures
import functools
import inspect
import json
import logging  # allow-direct-logging
import os
import ssl
import sys
import traceback
import warnings
from collections.abc import Callable
from contextlib import asynccontextmanager
from importlib.metadata import version as parse_version
from pathlib import Path
from typing import Annotated, Any, get_origin

import httpx
import rich.pretty
import yaml
from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi import Path as FastapiPath
from fastapi.exceptions import RequestValidationError
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse, StreamingResponse
from openai import BadRequestError
from pydantic import BaseModel, ValidationError

from llama_stack.apis.common.errors import ConflictError, ResourceNotFoundError
from llama_stack.apis.common.responses import PaginatedResponse
from llama_stack.cli.utils import add_config_distro_args, get_config_from_args
from llama_stack.core.access_control.access_control import AccessDeniedError
from llama_stack.core.datatypes import (
    AuthenticationRequiredError,
    LoggingConfig,
    StackRunConfig,
    process_cors_config,
)
from llama_stack.core.distribution import builtin_automatically_routed_apis
from llama_stack.core.external import load_external_apis
from llama_stack.core.request_headers import (
    PROVIDER_DATA_VAR,
    request_provider_data_context,
    user_from_scope,
)
from llama_stack.core.server.routes import get_all_api_routes
from llama_stack.core.stack import (
    Stack,
    cast_image_name_to_string,
    replace_env_vars,
    validate_env_pair,
)
from llama_stack.core.utils.config import redact_sensitive_fields
from llama_stack.core.utils.config_resolution import Mode, resolve_config_or_distro
from llama_stack.core.utils.context import preserve_contexts_async_generator
from llama_stack.log import get_logger
from llama_stack.providers.datatypes import Api


from .auth import AuthenticationMiddleware
from .quota import QuotaMiddleware

REPO_ROOT = Path(__file__).parent.parent.parent.parent

logger = get_logger(name=__name__, category="core::server")


def warn_with_traceback(message, category, filename, lineno, file=None, line=None):
    log = file if hasattr(file, "write") else sys.stderr
    if log is None:
        return
    traceback.print_stack(file=log)
    log.write(warnings.formatwarning(message, category, filename, lineno, line))


if os.environ.get("LLAMA_STACK_TRACE_WARNINGS"):
    warnings.showwarning = warn_with_traceback


def create_sse_event(data: Any) -> str:
    if isinstance(data, BaseModel):
        data = data.model_dump_json()
    else:
        data = json.dumps(data)

    return f"data: {data}\n\n"


async def global_exception_handler(request: Request, exc: Exception):
    traceback.print_exception(exc)
    http_exc = translate_exception(exc)

    return JSONResponse(status_code=http_exc.status_code, content={"error": {"detail": http_exc.detail}})


def translate_exception(exc: Exception) -> HTTPException | RequestValidationError:
    if isinstance(exc, ValidationError):
        exc = RequestValidationError(exc.errors())

    if isinstance(exc, RequestValidationError):
        return HTTPException(
            status_code=httpx.codes.BAD_REQUEST,
            detail={
                "errors": [
                    {
                        "loc": list(error["loc"]),
                        "msg": error["msg"],
                        "type": error["type"],
                    }
                    for error in exc.errors()
                ]
            },
        )
    elif isinstance(exc, ConflictError):
        return HTTPException(status_code=httpx.codes.CONFLICT, detail=str(exc))
    elif isinstance(exc, ResourceNotFoundError):
        return HTTPException(status_code=httpx.codes.NOT_FOUND, detail=str(exc))
    elif isinstance(exc, ValueError):
        return HTTPException(status_code=httpx.codes.BAD_REQUEST, detail=f"Invalid value: {str(exc)}")
    elif isinstance(exc, BadRequestError):
        return HTTPException(status_code=httpx.codes.BAD_REQUEST, detail=str(exc))
    elif isinstance(exc, PermissionError | AccessDeniedError):
        return HTTPException(status_code=httpx.codes.FORBIDDEN, detail=f"Permission denied: {str(exc)}")
    elif isinstance(exc, ConnectionError | httpx.ConnectError):
        return HTTPException(status_code=httpx.codes.BAD_GATEWAY, detail=str(exc))
    elif isinstance(exc, asyncio.TimeoutError | TimeoutError):
        return HTTPException(status_code=httpx.codes.GATEWAY_TIMEOUT, detail=f"Operation timed out: {str(exc)}")
    elif isinstance(exc, NotImplementedError):
        return HTTPException(status_code=httpx.codes.NOT_IMPLEMENTED, detail=f"Not implemented: {str(exc)}")
    elif isinstance(exc, AuthenticationRequiredError):
        return HTTPException(status_code=httpx.codes.UNAUTHORIZED, detail=f"Authentication required: {str(exc)}")
    else:
        return HTTPException(
            status_code=httpx.codes.INTERNAL_SERVER_ERROR,
            detail="Internal server error: An unexpected error occurred.",
        )


class StackApp(FastAPI):
    """
    A wrapper around the FastAPI application to hold a reference to the Stack instance so that we can
    start background tasks (e.g. refresh model registry periodically) from the lifespan context manager.
    """

    def __init__(self, config: StackRunConfig, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.stack: Stack = Stack(config)

        # This code is called from a running event loop managed by uvicorn so we cannot simply call
        # asyncio.run() to initialize the stack. We cannot await either since this is not an async
        # function.
        # As a workaround, we use a thread pool executor to run the initialize() method
        # in a separate thread.
        with concurrent.futures.ThreadPoolExecutor() as executor:
            future = executor.submit(asyncio.run, self.stack.initialize())
            future.result()


@asynccontextmanager
async def lifespan(app: StackApp):
    logger.info("Starting up")
    assert app.stack is not None
    app.stack.create_registry_refresh_task()
    yield
    logger.info("Shutting down")
    await app.stack.shutdown()


def is_streaming_request(func_name: str, request: Request, **kwargs):
    # TODO: pass the api method and punt it to the Protocol definition directly
    return kwargs.get("stream", False)


async def maybe_await(value):
    if inspect.iscoroutine(value):
        return await value
    return value


async def sse_generator(event_gen_coroutine):
    event_gen = None
    try:
        event_gen = await event_gen_coroutine
        async for item in event_gen:
            yield create_sse_event(item)
    except asyncio.CancelledError:
        logger.info("Generator cancelled")
        if event_gen:
            await event_gen.aclose()
    except Exception as e:
        logger.exception("Error in sse_generator")
        yield create_sse_event(
            {
                "error": {
                    "message": str(translate_exception(e)),
                },
            }
        )


async def log_request_pre_validation(request: Request):
    if request.method in ("POST", "PUT", "PATCH"):
        try:
            body_bytes = await request.body()
            if body_bytes:
                try:
                    parsed_body = json.loads(body_bytes.decode())
                    log_output = rich.pretty.pretty_repr(parsed_body)
                except (json.JSONDecodeError, UnicodeDecodeError):
                    log_output = repr(body_bytes)
                logger.debug(f"Incoming raw request body for {request.method} {request.url.path}:\n{log_output}")
            else:
                logger.debug(f"Incoming {request.method} {request.url.path} request with empty body.")
        except Exception as e:
            logger.warning(f"Could not read or log request body for {request.method} {request.url.path}: {e}")


def create_dynamic_typed_route(func: Any, method: str, route: str) -> Callable:
    @functools.wraps(func)
    async def route_handler(request: Request, **kwargs):
        # Get auth attributes from the request scope
        user = user_from_scope(request.scope)

        await log_request_pre_validation(request)

        # Use context manager with both provider data and auth attributes
        with request_provider_data_context(request.headers, user):
            is_streaming = is_streaming_request(func.__name__, request, **kwargs)

            try:
                if is_streaming:
                    gen = preserve_contexts_async_generator(
                        sse_generator(func(**kwargs)), [PROVIDER_DATA_VAR]
                    )
                    return StreamingResponse(gen, media_type="text/event-stream")
                else:
                    value = func(**kwargs)
                    result = await maybe_await(value)
                    if isinstance(result, PaginatedResponse) and result.url is None:
                        result.url = route

                    if method.upper() == "DELETE" and result is None:
                        return Response(status_code=httpx.codes.NO_CONTENT)

                    return result
            except Exception as e:
                if logger.isEnabledFor(logging.INFO):
                    logger.exception(f"Error executing endpoint {route=} {method=}")
                else:
                    logger.error(f"Error executing endpoint {route=} {method=}: {str(e)}")
                raise translate_exception(e) from e

    sig = inspect.signature(func)

    new_params = [inspect.Parameter("request", inspect.Parameter.POSITIONAL_OR_KEYWORD, annotation=Request)]
    new_params.extend(sig.parameters.values())

    path_params = extract_path_params(route)
    if method == "post":
        # Annotate parameters that are in the path with Path(...) and others with Body(...),
        # but preserve existing File() and Form() annotations for multipart form data
        new_params = (
            [new_params[0]]
            + [
                (
                    param.replace(annotation=Annotated[param.annotation, FastapiPath(..., title=param.name)])
                    if param.name in path_params
                    else (
                        param  # Keep original annotation if it's already an Annotated type
                        if get_origin(param.annotation) is Annotated
                        else param.replace(annotation=Annotated[param.annotation, Body(..., embed=True)])
                    )
                )
                for param in new_params[1:]
            ]
        )

    setattr(route_handler, "__signature__", sig.replace(parameters=new_params))
    return route_handler


class ClientVersionMiddleware:
    def __init__(self, app):
        self.app = app
        self.server_version = parse_version("llama-stack")

    async def __call__(self, scope, receive, send):
        if scope["type"] == "http":
            headers = dict(scope.get("headers", []))
            client_version = headers.get(b"x-llamastack-client-version", b"").decode()
            if client_version:
                try:
                    client_version_parts = tuple(map(int, client_version.split(".")[:2]))
                    server_version_parts = tuple(map(int, self.server_version.split(".")[:2]))
                    if client_version_parts != server_version_parts:

                        async def send_version_error(send):
                            await send(
                                {
                                    "type": "http.response.start",
                                    "status": httpx.codes.UPGRADE_REQUIRED,
                                    "headers": [[b"content-type", b"application/json"]],
                                }
                            )
                            error_msg = json.dumps(
                                {
                                    "error": {
                                        "message": f"Client version {client_version} is not compatible with server version {self.server_version}. Please update your client."
                                    }
                                }
                            ).encode()
                            await send({"type": "http.response.body", "body": error_msg})

                        return await send_version_error(send)
                except (ValueError, IndexError):
                    # If version parsing fails, let the request through
                    pass

        return await self.app(scope, receive, send)


def create_app(
    config_file: str | None = None,
    env_vars: list[str] | None = None,
) -> StackApp:
    """Create and configure the FastAPI application.

    Args:
        config_file: Path to config file. If None, uses LLAMA_STACK_CONFIG env var or default resolution.
        env_vars: List of environment variables in KEY=value format.
        disable_version_check: Whether to disable version checking. If None, uses LLAMA_STACK_DISABLE_VERSION_CHECK env var.

    Returns:
        Configured StackApp instance.
    """
    config_file = config_file or os.getenv("LLAMA_STACK_CONFIG")
    if config_file is None:
        raise ValueError("No config file provided and LLAMA_STACK_CONFIG env var is not set")

    config_path = resolve_config_or_distro(config_file, Mode.RUN)

    # Load and process configuration
    logger_config = None

    with open(config_path) as fp:
        config_contents = yaml.safe_load(fp)
        if isinstance(config_contents, dict) and (cfg := config_contents.get("logging_config")):
            logger_config = LoggingConfig(**cfg)
        logger = get_logger(name=__name__, category="core::server", config=logger_config)

        if env_vars:
            for env_pair in env_vars:
                try:
                    key, value = validate_env_pair(env_pair)
                    logger.info(f"Setting environment variable {key} => {value}")
                    os.environ[key] = value
                except ValueError as e:
                    logger.error(f"Error: {str(e)}")
                    raise ValueError(f"Invalid environment variable format: {env_pair}") from e

        config = replace_env_vars(config_contents)
        config = StackRunConfig(**cast_image_name_to_string(config))

    _log_run_config(run_config=config)

    app = StackApp(
        lifespan=lifespan,
        docs_url="/docs",
        redoc_url="/redoc",
        openapi_url="/openapi.json",
        config=config,
    )

    if not os.environ.get("LLAMA_STACK_DISABLE_VERSION_CHECK"):
        app.add_middleware(ClientVersionMiddleware)

    impls = app.stack.get_impls()

    if config.server.auth:
        logger.info(f"Enabling authentication with provider: {config.server.auth.provider_config.type.value}")
        app.add_middleware(AuthenticationMiddleware, auth_config=config.server.auth, impls=impls)
    else:
        if config.server.quota:
            quota = config.server.quota
            logger.warning(
                "Configured authenticated_max_requests (%d) but no auth is enabled; "
                "falling back to anonymous_max_requests (%d) for all the requests",
                quota.authenticated_max_requests,
                quota.anonymous_max_requests,
            )

    if config.server.quota:
        logger.info("Enabling quota middleware for authenticated and anonymous clients")

        quota = config.server.quota
        anonymous_max_requests = quota.anonymous_max_requests
        # if auth is disabled, use the anonymous max requests
        authenticated_max_requests = quota.authenticated_max_requests if config.server.auth else anonymous_max_requests

        kv_config = quota.kvstore
        window_map = {"day": 86400}
        window_seconds = window_map[quota.period.value]

        app.add_middleware(
            QuotaMiddleware,
            kv_config=kv_config,
            anonymous_max_requests=anonymous_max_requests,
            authenticated_max_requests=authenticated_max_requests,
            window_seconds=window_seconds,
        )

    if config.server.cors:
        logger.info("Enabling CORS")
        cors_config = process_cors_config(config.server.cors)
        if cors_config:
            app.add_middleware(CORSMiddleware, **cors_config.model_dump())

    if Api.telemetry in impls:
        impls[Api.telemetry].fastapi_middleware(app)
        impls[Api.telemetry].sqlalchemy_instrumentation()

    # Load external APIs if configured
    external_apis = load_external_apis(config)
    all_routes = get_all_api_routes(external_apis)

    if config.apis:
        apis_to_serve = set(config.apis)
    else:
        apis_to_serve = {api.value for api in impls.keys()}

    for inf in builtin_automatically_routed_apis():
        # if we do not serve the corresponding router API, we should not serve the routing table API
        if inf.router_api.value not in apis_to_serve:
            continue
        apis_to_serve.add(inf.routing_table_api.value)

    apis_to_serve.add("inspect")
    apis_to_serve.add("providers")
    apis_to_serve.add("prompts")
    apis_to_serve.add("conversations")
    for api_str in apis_to_serve:
        api = Api(api_str)

        routes = all_routes[api]
        try:
            impl = impls[api]
        except KeyError as e:
            raise ValueError(f"Could not find provider implementation for {api} API") from e

        for route, _ in routes:
            if not hasattr(impl, route.name):
                # ideally this should be a typing violation already
                raise ValueError(f"Could not find method {route.name} on {impl}!")

            impl_method = getattr(impl, route.name)
            # Filter out HEAD method since it's automatically handled by FastAPI for GET routes
            route_methods = route.methods or []
            available_methods = [m for m in route_methods if m != "HEAD"]
            if not available_methods:
                raise ValueError(f"No methods found for {route.name} on {impl}")
            method = available_methods[0]
            logger.debug(f"{method} {route.path}")

            with warnings.catch_warnings():
                warnings.filterwarnings("ignore", category=UserWarning, module="pydantic._internal._fields")
                getattr(app, method.lower())(route.path, response_model=None)(
                    create_dynamic_typed_route(
                        impl_method,
                        method.lower(),
                        route.path,
                    )
                )

    logger.debug(f"serving APIs: {apis_to_serve}")

    app.exception_handler(RequestValidationError)(global_exception_handler)
    app.exception_handler(Exception)(global_exception_handler)

    return app


def main(args: argparse.Namespace | None = None):
    """Start the LlamaStack server."""
    parser = argparse.ArgumentParser(description="Start the LlamaStack server.")

    add_config_distro_args(parser)
    parser.add_argument(
        "--port",
        type=int,
        default=int(os.getenv("LLAMA_STACK_PORT", 8321)),
        help="Port to listen on",
    )
    parser.add_argument(
        "--env",
        action="append",
        help="Environment variables in KEY=value format. Can be specified multiple times.",
    )

    # Determine whether the server args are being passed by the "run" command, if this is the case
    # the args will be passed as a Namespace object to the main function, otherwise they will be
    # parsed from the command line
    if args is None:
        args = parser.parse_args()

    config_or_distro = get_config_from_args(args)

    try:
        app = create_app(
            config_file=config_or_distro,
            env_vars=args.env,
        )
    except Exception as e:
        logger.error(f"Error creating app: {str(e)}")
        sys.exit(1)

    config_path = resolve_config_or_distro(config_or_distro, Mode.RUN)
    with open(config_path) as fp:
        config_contents = yaml.safe_load(fp)
        if isinstance(config_contents, dict) and (cfg := config_contents.get("logging_config")):
            logger_config = LoggingConfig(**cfg)
        else:
            logger_config = None
        config = StackRunConfig(**cast_image_name_to_string(replace_env_vars(config_contents)))

    import uvicorn

    # Configure SSL if certificates are provided
    port = args.port or config.server.port

    ssl_config = None
    keyfile = config.server.tls_keyfile
    certfile = config.server.tls_certfile

    if keyfile and certfile:
        ssl_config = {
            "ssl_keyfile": keyfile,
            "ssl_certfile": certfile,
        }
        if config.server.tls_cafile:
            ssl_config["ssl_ca_certs"] = config.server.tls_cafile
            ssl_config["ssl_cert_reqs"] = ssl.CERT_REQUIRED
            logger.info(
                f"HTTPS enabled with certificates:\n  Key: {keyfile}\n  Cert: {certfile}\n  CA: {config.server.tls_cafile}"
            )
        else:
            logger.info(f"HTTPS enabled with certificates:\n  Key: {keyfile}\n  Cert: {certfile}")

    listen_host = config.server.host or ["::", "0.0.0.0"]
    logger.info(f"Listening on {listen_host}:{port}")

    uvicorn_config = {
        "app": app,
        "host": listen_host,
        "port": port,
        "lifespan": "on",
        "log_level": logger.getEffectiveLevel(),
        "log_config": logger_config,
    }
    if ssl_config:
        uvicorn_config.update(ssl_config)

    # We need to catch KeyboardInterrupt because uvicorn's signal handling
    # re-raises SIGINT signals using signal.raise_signal(), which Python
    # converts to KeyboardInterrupt. Without this catch, we'd get a confusing
    # stack trace when using Ctrl+C or kill -2 (SIGINT).
    # SIGTERM (kill -15) works fine without this because Python doesn't
    # have a default handler for it.
    #
    # Another approach would be to ignore SIGINT entirely - let uvicorn handle it through its own
    # signal handling but this is quite intrusive and not worth the effort.
    try:
        asyncio.run(uvicorn.Server(uvicorn.Config(**uvicorn_config)).serve())
    except (KeyboardInterrupt, SystemExit):
        logger.info("Received interrupt signal, shutting down gracefully...")


def _log_run_config(run_config: StackRunConfig):
    """Logs the run config with redacted fields and disabled providers removed."""
    logger.info("Run configuration:")
    safe_config = redact_sensitive_fields(run_config.model_dump(mode="json"))
    clean_config = remove_disabled_providers(safe_config)
    logger.info(yaml.dump(clean_config, indent=2))


def extract_path_params(route: str) -> list[str]:
    segments = route.split("/")
    params = [seg[1:-1] for seg in segments if seg.startswith("{") and seg.endswith("}")]
    # to handle path params like {param:path}
    params = [param.split(":")[0] for param in params]
    return params


def remove_disabled_providers(obj):
    if isinstance(obj, dict):
        keys = ["provider_id", "shield_id", "provider_model_id", "model_id"]
        if any(k in obj and obj[k] in ("__disabled__", "", None) for k in keys):
            return None
        return {k: v for k, v in ((k, remove_disabled_providers(v)) for k, v in obj.items()) if v is not None}
    elif isinstance(obj, list):
        return [item for item in (remove_disabled_providers(i) for i in obj) if item is not None]
    else:
        return obj


if __name__ == "__main__":
    main()