src/app/api/routes.py

"""API routes for the voice agent."""
from __future__ import annotations

import json
import uuid
from pathlib import Path
import shutil

import anyio
from fastapi import APIRouter, File, Form, UploadFile, WebSocket, WebSocketDisconnect
from fastapi.responses import FileResponse, JSONResponse
from starlette.websockets import WebSocketState

from ..core.errors import SpeechError, ValidationError, LLMError
from ..core.logging import get_logger
from ..services.pipeline import VoicePipeline
from ..services.agent.agent_pipeline import AgentPipeline
from ..services.stt import SpeechToTextService
from ..services.vad import SileroVADStream
from ..utils.audio import encode_base64
from ..core.config import get_settings

router = APIRouter()

MAX_FILE_SIZE_BYTES = 15 * 1024 * 1024
DEFAULT_STREAM_CONTENT_TYPE = "audio/ogg"
NO_MATCH_REPLY = "Sorry, I didn't catch that. Please try again."


@router.get("/health")
async def health() -> dict[str, str]:
    """Health check endpoint."""
    return {"status": "ok"}


@router.get("/ws-demo")
async def ws_demo() -> FileResponse:
    """Serve a simple WebSocket streaming demo page."""
    demo_path = Path(__file__).resolve().parent.parent / "utils" / "ws_demo.html"
    return FileResponse(demo_path)


@router.post("/v1/agent/upload")
async def agent_upload(files: list[UploadFile] = File(...)) -> JSONResponse:
    """Upload files for local RAG indexing."""
    settings = get_settings()
    data_dir = Path(settings.data_dir)
    data_dir.mkdir(parents=True, exist_ok=True)
    saved: list[str] = []
    for file in files:
        content = await file.read()
        if not content:
            continue
        target = data_dir / file.filename
        target.write_bytes(content)
        saved.append(file.filename)
    await AgentPipeline().rebuild_rag()
    return JSONResponse({"status": "ok", "files": saved})


@router.post("/v1/agent/reset")
async def agent_reset() -> JSONResponse:
    """Reset local RAG + memory storage."""
    settings = get_settings()
    data_dir = Path(settings.data_dir)
    store_dir = Path(settings.vector_store_dir)
    if data_dir.exists():
        shutil.rmtree(data_dir, ignore_errors=True)
    if store_dir.exists():
        shutil.rmtree(store_dir, ignore_errors=True)
    data_dir.mkdir(parents=True, exist_ok=True)
    store_dir.mkdir(parents=True, exist_ok=True)
    AgentPipeline().reset()
    return JSONResponse({"status": "ok"})


@router.post("/v1/voice/file")
async def voice_file(
    file: UploadFile = File(...),
    prompt: str | None = Form(default=None),
    return_audio: bool = Form(default=True),
    llm_provider: str | None = Form(default=None),
) -> JSONResponse:
    """Process uploaded audio file and return transcript + reply."""
    request_id = str(uuid.uuid4())
    log = get_logger(request_id=request_id, endpoint="/v1/voice/file")

    if not file:
        raise ValidationError(code="file_missing", message="Audio file is required.")

    audio_bytes = await file.read()
    if not audio_bytes:
        raise ValidationError(code="file_empty", message="Audio file is empty.")
    if len(audio_bytes) > MAX_FILE_SIZE_BYTES:
        raise ValidationError(code="file_too_large", message="File exceeds 15MB limit.")

    pipeline = VoicePipeline()
    if llm_provider and llm_provider not in {
        "foundry_agent",
        "azure_openai",
        "local_agent",
    }:
        raise ValidationError(
            code="llm_provider",
            message="LLM provider must be 'foundry_agent', 'azure_openai', or 'local_agent'.",
        )

    if llm_provider == "local_agent":
        agent = AgentPipeline()
        result = await agent.run_audio(
            audio_bytes=audio_bytes,
            filename=file.filename,
            content_type=file.content_type,
            prompt=prompt,
            return_audio=return_audio,
            llm_provider="azure_openai",
        )
    else:
        result = await pipeline.run(
            audio_bytes=audio_bytes,
            filename=file.filename,
            content_type=file.content_type,
            prompt=prompt,
            return_audio=return_audio,
            llm_provider=llm_provider,
        )

    reply_audio_base64 = (
        encode_base64(result.reply_audio) if result.reply_audio else None
    )

    response_body = {
        "transcript": result.transcript,
        "reply_text": result.reply_text,
        "audio_format": "wav",
        "reply_audio_base64": reply_audio_base64,
        "timings_ms": result.timings_ms,
    }

    log.info(
        "voice_request_complete",
        file_name=file.filename,
        file_size=len(audio_bytes),
        timings_ms=result.timings_ms,
        return_audio=return_audio,
    )

    return JSONResponse(response_body)


@router.websocket("/ws/voice")
async def voice_stream(websocket: WebSocket) -> None:
    """Stream audio over WebSocket, then process on 'stop'."""
    await websocket.accept()
    request_id = str(uuid.uuid4())
    log = get_logger(request_id=request_id, endpoint="/ws/voice")
    buffer = bytearray()
    content_type: str | None = DEFAULT_STREAM_CONTENT_TYPE
    prompt: str | None = None
    return_audio = True
    stt_session = None
    frames_sent: int | None = None
    avg_rms: float | None = None
    llm_provider: str | None = None
    vad_stream: SileroVADStream | None = None
    segment_processing = False
    session_id: str | None = None

    async def _finalize_segment() -> None:
        nonlocal stt_session, segment_processing, vad_stream
        if stt_session is None:
            raise ValidationError(
                code="stt_not_started", message="STT session not started."
            )
        if not buffer:
            return
        segment_processing = True
        try:
            stt_result = await anyio.to_thread.run_sync(stt_session.finish)
        except SpeechError as exc:
            if exc.code in {"stt_empty", "stt_no_match"}:
                try:
                    stt_result = await anyio.to_thread.run_sync(
                        SpeechToTextService().transcribe,
                        bytes(buffer),
                        None,
                        content_type,
                    )
                except SpeechError as exc_fallback:
                    if exc_fallback.code in {"stt_empty", "stt_no_match"}:
                        await websocket.send_json(
                            {
                                "event": "result",
                                "transcript": "",
                                "reply_text": NO_MATCH_REPLY,
                                "audio_format": "wav",
                                "reply_audio_base64": None,
                                "timings_ms": {"stt": 0, "llm": 0, "tts": 0, "total": 0},
                            }
                        )
                        buffer.clear()
                        stt_session = SpeechToTextService().start_streaming(
                            end_silence_ms=1400, initial_silence_ms=5000
                        )
                        vad_stream = SileroVADStream()
                        return
                    raise
            else:
                raise

        await websocket.send_json(
            {"event": "transcript", "transcript": stt_result.transcript}
        )
        if llm_provider == "local_agent":
            agent = AgentPipeline()
            result = await agent.run_with_transcript(
                transcript=stt_result.transcript,
                language=stt_result.language,
                prompt=prompt,
                return_audio=return_audio,
                llm_provider="azure_openai",
                session_id=session_id,
            )
        else:
            pipeline = VoicePipeline()
            result = await pipeline.run(
                audio_bytes=bytes(buffer),
                filename=None,
                content_type=content_type,
                prompt=prompt,
                return_audio=return_audio,
                transcript_override=stt_result.transcript,
                language_override=stt_result.language,
                llm_provider=llm_provider,
            )
        response_body = {
            "event": "result",
            "transcript": result.transcript,
            "reply_text": result.reply_text,
            "audio_format": "wav",
            "reply_audio_base64": None,
            "timings_ms": result.timings_ms,
        }
        log.info(
            "voice_stream_complete",
            bytes_received=len(buffer),
            timings_ms=result.timings_ms,
            return_audio=return_audio,
            content_type=content_type,
            frames_sent=frames_sent,
            avg_rms=avg_rms,
        )
        await websocket.send_json(response_body)
        if result.reply_audio and return_audio:
            await websocket.send_bytes(result.reply_audio)
        buffer.clear()
        stt_session = SpeechToTextService().start_streaming(
            end_silence_ms=1200, initial_silence_ms=5000
        )
        vad_stream = SileroVADStream()
        segment_processing = False

    try:
        while True:
            try:
                message = await websocket.receive()
            except RuntimeError:
                log.info("voice_stream_disconnect")
                break

            if "bytes" in message and message["bytes"] is not None:
                chunk = message["bytes"]
                if stt_session is not None:
                    stt_session.write(chunk)
                buffer.extend(chunk)
                if vad_stream is not None and not segment_processing:
                    decision = vad_stream.update(chunk)
                    if decision.speech_ended:
                        await _finalize_segment()
                if len(buffer) > MAX_FILE_SIZE_BYTES:
                    raise ValidationError(
                        code="file_too_large", message="Stream exceeds 15MB limit."
                    )
                continue

            if "text" in message and message["text"] is not None:
                try:
                    payload = json.loads(message["text"])
                except json.JSONDecodeError as exc:
                    raise ValidationError(
                        code="invalid_message", message="Invalid JSON message."
                    ) from exc

                event = str(payload.get("event", "")).lower()
                if event == "start":
                    content_type = payload.get("content_type") or content_type
                    prompt = payload.get("prompt")
                    return_audio = payload.get("return_audio", True)
                    llm_provider = payload.get("llm_provider", llm_provider)
                    session_id = payload.get("session_id", session_id) or request_id
                    if llm_provider and llm_provider not in {
                        "foundry_agent",
                        "azure_openai",
                        "local_agent",
                    }:
                        raise ValidationError(
                            code="llm_provider",
                            message=(
                                "LLM provider must be 'foundry_agent', 'azure_openai', or 'local_agent'."
                            ),
                        )
                    stt_session = SpeechToTextService().start_streaming(
                        end_silence_ms=1200, initial_silence_ms=5000
                    )
                    vad_stream = SileroVADStream()
                    continue

                if event == "stop":
                    if not buffer:
                        raise ValidationError(
                            code="file_empty", message="Audio stream is empty."
                        )
                    if stt_session is None:
                        raise ValidationError(
                            code="stt_not_started",
                            message="STT session not started.",
                        )
                    prompt = payload.get("prompt", prompt)
                    return_audio = payload.get("return_audio", return_audio)
                    llm_provider = payload.get("llm_provider", llm_provider)
                    session_id = payload.get("session_id", session_id) or request_id
                    frames_sent = payload.get("frames_sent", frames_sent)
                    avg_rms = payload.get("avg_rms", avg_rms)
                    if llm_provider and llm_provider not in {
                        "foundry_agent",
                        "azure_openai",
                        "local_agent",
                    }:
                        raise ValidationError(
                            code="llm_provider",
                            message=(
                                "LLM provider must be 'foundry_agent', 'azure_openai', or 'local_agent'."
                            ),
                        )
                    await _finalize_segment()
                    break

                if event == "segment_end":
                    if not buffer:
                        continue
                    prompt = payload.get("prompt", prompt)
                    return_audio = payload.get("return_audio", return_audio)
                    llm_provider = payload.get("llm_provider", llm_provider)
                    session_id = payload.get("session_id", session_id) or request_id
                    frames_sent = payload.get("frames_sent", frames_sent)
                    avg_rms = payload.get("avg_rms", avg_rms)
                    if llm_provider and llm_provider not in {
                        "foundry_agent",
                        "azure_openai",
                        "local_agent",
                    }:
                        raise ValidationError(
                            code="llm_provider",
                            message=(
                                "LLM provider must be 'foundry_agent', 'azure_openai', or 'local_agent'."
                            ),
                        )
                    if vad_stream is not None and not vad_stream.has_speech():
                        await websocket.send_json(
                            {
                                "event": "result",
                                "transcript": "",
                                "reply_text": NO_MATCH_REPLY,
                                "audio_format": "wav",
                                "reply_audio_base64": None,
                                "timings_ms": {"stt": 0, "llm": 0, "tts": 0, "total": 0},
                            }
                        )
                        buffer.clear()
                        vad_stream.reset()
                        continue
                    await _finalize_segment()
                    continue

                raise ValidationError(
                    code="invalid_event",
                    message="Event must be 'start', 'stop', or 'segment_end'.",
                )
    except WebSocketDisconnect:
        log.info("voice_stream_disconnect")
    except ValidationError as exc:
        log.warning(
            "voice_stream_error",
            code=exc.code,
            message=exc.message,
            bytes_received=len(buffer),
            frames_sent=frames_sent,
            avg_rms=avg_rms,
        )
        if websocket.application_state == WebSocketState.CONNECTED:
            await websocket.send_json(
                {"event": "error", "error": {"code": exc.code, "message": exc.message}}
            )
            await websocket.close()
    except LLMError as exc:
        log.warning(
            "voice_stream_error",
            code=exc.code,
            message=exc.message,
            details=exc.details,
            bytes_received=len(buffer),
            frames_sent=frames_sent,
            avg_rms=avg_rms,
        )
        if websocket.application_state == WebSocketState.CONNECTED:
            await websocket.send_json(
                {
                    "event": "error",
                    "error": {"code": exc.code, "message": exc.message},
                }
            )
            if exc.code != "llm_guardrail":
                await websocket.close()
        return
    except SpeechError as exc:
        log.warning(
            "voice_stream_error",
            code=exc.code,
            message=exc.message,
            details=exc.details,
            bytes_received=len(buffer),
            frames_sent=frames_sent,
            avg_rms=avg_rms,
        )
        if websocket.application_state == WebSocketState.CONNECTED:
            await websocket.send_json(
                {
                    "event": "error",
                    "error": {
                        "code": exc.code,
                        "message": exc.message,
                        "details": exc.details,
                    },
                }
            )
            await websocket.close()
    except Exception as exc:  # pragma: no cover - safety net
        log.error("voice_stream_unhandled", error=repr(exc))
        if websocket.application_state == WebSocketState.CONNECTED:
            await websocket.send_json(
                {
                    "event": "error",
                    "error": {"code": "internal_error", "message": "Server error."},
                }
            )
            await websocket.close()