api/routes.py

"""FastAPI route handlers."""

import traceback
import uuid

from fastapi import APIRouter, Depends, HTTPException, Request, Response
from fastapi.responses import StreamingResponse
from loguru import logger

from config.settings import Settings
from providers.common import get_user_facing_error_message
from providers.exceptions import InvalidRequestError, ProviderError

from .dependencies import get_provider_for_type, get_settings, require_api_key
from .models.anthropic import MessagesRequest, TokenCountRequest
from .models.responses import ModelResponse, ModelsListResponse, TokenCountResponse
from .optimization_handlers import try_optimizations
from .request_utils import get_token_count

router = APIRouter()


SUPPORTED_CLAUDE_MODELS = [
    ModelResponse(
        id="claude-opus-4-20250514",
        display_name="Claude Opus 4",
        created_at="2025-05-14T00:00:00Z",
    ),
    ModelResponse(
        id="claude-sonnet-4-20250514",
        display_name="Claude Sonnet 4",
        created_at="2025-05-14T00:00:00Z",
    ),
    ModelResponse(
        id="claude-haiku-4-20250514",
        display_name="Claude Haiku 4",
        created_at="2025-05-14T00:00:00Z",
    ),
    ModelResponse(
        id="claude-3-opus-20240229",
        display_name="Claude 3 Opus",
        created_at="2024-02-29T00:00:00Z",
    ),
    ModelResponse(
        id="claude-3-5-sonnet-20241022",
        display_name="Claude 3.5 Sonnet",
        created_at="2024-10-22T00:00:00Z",
    ),
    ModelResponse(
        id="claude-3-haiku-20240307",
        display_name="Claude 3 Haiku",
        created_at="2024-03-07T00:00:00Z",
    ),
    ModelResponse(
        id="claude-3-5-haiku-20241022",
        display_name="Claude 3.5 Haiku",
        created_at="2024-10-22T00:00:00Z",
    ),
]


def _probe_response(allow: str) -> Response:
    """Return an empty success response for compatibility probes."""
    return Response(status_code=204, headers={"Allow": allow})


# =============================================================================
# Routes
# =============================================================================
@router.post("/v1/messages")
async def create_message(
    request_data: MessagesRequest,
    raw_request: Request,
    settings: Settings = Depends(get_settings),
    _auth=Depends(require_api_key),
):
    """Create a message (always streaming)."""

    try:
        if not request_data.messages:
            raise InvalidRequestError("messages cannot be empty")

        optimized = try_optimizations(request_data, settings)
        if optimized is not None:
            return optimized
        logger.debug("No optimization matched, routing to provider")

        # Resolve provider from the model-aware mapping
        provider_type = Settings.parse_provider_type(
            request_data.resolved_provider_model or settings.model
        )
        provider = get_provider_for_type(provider_type)

        request_id = f"req_{uuid.uuid4().hex[:12]}"
        logger.info(
            "API_REQUEST: request_id={} model={} messages={}",
            request_id,
            request_data.model,
            len(request_data.messages),
        )
        logger.debug("FULL_PAYLOAD [{}]: {}", request_id, request_data.model_dump())

        input_tokens = get_token_count(
            request_data.messages, request_data.system, request_data.tools
        )
        return StreamingResponse(
            provider.stream_response(
                request_data,
                input_tokens=input_tokens,
                request_id=request_id,
            ),
            media_type="text/event-stream",
            headers={
                "X-Accel-Buffering": "no",
                "Cache-Control": "no-cache",
                "Connection": "keep-alive",
            },
        )

    except ProviderError:
        raise
    except Exception as e:
        logger.error(f"Error: {e!s}\n{traceback.format_exc()}")
        raise HTTPException(
            status_code=getattr(e, "status_code", 500),
            detail=get_user_facing_error_message(e),
        ) from e


@router.api_route("/v1/messages", methods=["HEAD", "OPTIONS"])
async def probe_messages(_auth=Depends(require_api_key)):
    """Respond to Claude compatibility probes for the messages endpoint."""
    return _probe_response("POST, HEAD, OPTIONS")


@router.post("/v1/messages/count_tokens")
async def count_tokens(request_data: TokenCountRequest, _auth=Depends(require_api_key)):
    """Count tokens for a request."""
    request_id = f"req_{uuid.uuid4().hex[:12]}"
    with logger.contextualize(request_id=request_id):
        try:
            tokens = get_token_count(
                request_data.messages, request_data.system, request_data.tools
            )
            logger.info(
                "COUNT_TOKENS: request_id={} model={} messages={} input_tokens={}",
                request_id,
                getattr(request_data, "model", "unknown"),
                len(request_data.messages),
                tokens,
            )
            return TokenCountResponse(input_tokens=tokens)
        except Exception as e:
            logger.error(
                "COUNT_TOKENS_ERROR: request_id={} error={}\n{}",
                request_id,
                get_user_facing_error_message(e),
                traceback.format_exc(),
            )
            raise HTTPException(
                status_code=500, detail=get_user_facing_error_message(e)
            ) from e


@router.api_route("/v1/messages/count_tokens", methods=["HEAD", "OPTIONS"])
async def probe_count_tokens(_auth=Depends(require_api_key)):
    """Respond to Claude compatibility probes for the token count endpoint."""
    return _probe_response("POST, HEAD, OPTIONS")


@router.get("/")
async def root(
    settings: Settings = Depends(get_settings), _auth=Depends(require_api_key)
):
    """Root endpoint."""
    return {
        "status": "ok",
        "provider": settings.provider_type,
        "model": settings.model,
    }


@router.api_route("/", methods=["HEAD", "OPTIONS"])
async def probe_root(_auth=Depends(require_api_key)):
    """Respond to compatibility probes for the root endpoint."""
    return _probe_response("GET, HEAD, OPTIONS")


@router.get("/health")
async def health():
    """Health check endpoint."""
    return {"status": "healthy"}


@router.api_route("/health", methods=["HEAD", "OPTIONS"])
async def probe_health():
    """Respond to compatibility probes for the health endpoint."""
    return _probe_response("GET, HEAD, OPTIONS")


@router.get("/v1/models", response_model=ModelsListResponse)
async def list_models(_auth=Depends(require_api_key)):
    """List the Claude model ids this proxy advertises for compatibility."""
    return ModelsListResponse(
        data=SUPPORTED_CLAUDE_MODELS,
        first_id=SUPPORTED_CLAUDE_MODELS[0].id if SUPPORTED_CLAUDE_MODELS else None,
        has_more=False,
        last_id=SUPPORTED_CLAUDE_MODELS[-1].id if SUPPORTED_CLAUDE_MODELS else None,
    )


@router.post("/stop")
async def stop_cli(request: Request, _auth=Depends(require_api_key)):
    """Stop all CLI sessions and pending tasks."""
    handler = getattr(request.app.state, "message_handler", None)
    if not handler:
        # Fallback if messaging not initialized
        cli_manager = getattr(request.app.state, "cli_manager", None)
        if cli_manager:
            await cli_manager.stop_all()
            logger.info("STOP_CLI: source=cli_manager cancelled_count=N/A")
            return {"status": "stopped", "source": "cli_manager"}
        raise HTTPException(status_code=503, detail="Messaging system not initialized")

    count = await handler.stop_all_tasks()
    logger.info("STOP_CLI: source=handler cancelled_count={}", count)
    return {"status": "stopped", "cancelled_count": count}