tts/tts_lifecycle_manager.py

"""

TTS Lifecycle Manager for Flare

===============================

Manages TTS instances lifecycle per session

"""
import asyncio
from typing import Dict, Optional, Any, List
from datetime import datetime
import traceback
import base64

from chat_session.event_bus import EventBus, Event, EventType, publish_error
from chat_session.resource_manager import ResourceManager, ResourceType
from tts.tts_factory import TTSFactory
from tts.tts_interface import TTSInterface
from tts.tts_preprocessor import TTSPreprocessor
from utils.logger import log_info, log_error, log_debug, log_warning


class TTSJob:
    """TTS synthesis job"""

    def __init__(self, job_id: str, session_id: str, text: str, is_welcome: bool = False):
        self.job_id = job_id
        self.session_id = session_id
        self.text = text
        self.is_welcome = is_welcome
        self.created_at = datetime.utcnow()
        self.completed_at: Optional[datetime] = None
        self.audio_data: Optional[bytes] = None
        self.error: Optional[str] = None
        self.chunks_sent = 0

    def complete(self, audio_data: bytes):
        """Mark job as completed"""
        self.audio_data = audio_data
        self.completed_at = datetime.utcnow()

    def fail(self, error: str):
        """Mark job as failed"""
        self.error = error
        self.completed_at = datetime.utcnow()


class TTSSession:
    """TTS session wrapper"""

    def __init__(self, session_id: str, tts_instance: TTSInterface):
        self.session_id = session_id
        self.tts_instance = tts_instance
        self.preprocessor: Optional[TTSPreprocessor] = None
        self.active_jobs: Dict[str, TTSJob] = {}
        self.completed_jobs: List[TTSJob] = []
        self.created_at = datetime.utcnow()
        self.last_activity = datetime.utcnow()
        self.total_jobs = 0
        self.total_chars = 0

    def update_activity(self):
        """Update last activity timestamp"""
        self.last_activity = datetime.utcnow()


class TTSLifecycleManager:
    """Manages TTS instances lifecycle"""

    def __init__(self, event_bus: EventBus, resource_manager: ResourceManager):
        self.event_bus = event_bus
        self.resource_manager = resource_manager
        self.tts_sessions: Dict[str, TTSSession] = {}
        self.chunk_size = 16384  # 16KB chunks for base64
        self._setup_event_handlers()
        self._setup_resource_pool()

    def _setup_event_handlers(self):
        """Subscribe to TTS-related events"""
        self.event_bus.subscribe(EventType.TTS_STARTED, self._handle_tts_start)
        self.event_bus.subscribe(EventType.SESSION_ENDED, self._handle_session_ended)

    def _setup_resource_pool(self):
        """Setup TTS instance pool"""
        self.resource_manager.register_pool(
            resource_type=ResourceType.TTS_INSTANCE,
            factory=self._create_tts_instance,
            max_idle=3,
            max_age_seconds=600  # 10 minutes
        )

    async def _create_tts_instance(self) -> Optional[TTSInterface]:
        """Factory for creating TTS instances"""
        try:
            tts_instance = TTSFactory.create_provider()
            if not tts_instance:
                log_warning("⚠️ No TTS provider configured")
                return None

            log_debug("🔊 Created new TTS instance")
            return tts_instance

        except Exception as e:
            log_error(f"❌ Failed to create TTS instance", error=str(e))
            return None

    async def _handle_tts_start(self, event: Event):
        """Handle TTS synthesis request"""
        session_id = event.session_id
        text = event.data.get("text", "")
        is_welcome = event.data.get("is_welcome", False)

        if not text:
            log_warning(f"⚠️ Empty text for TTS", session_id=session_id)
            return

        try:
            log_info(
                f"🔊 Starting TTS",
                session_id=session_id,
                text_length=len(text),
                is_welcome=is_welcome
            )

            # Get or create session
            if session_id not in self.tts_sessions:
                # Acquire TTS instance from pool
                resource_id = f"tts_{session_id}"
                tts_instance = await self.resource_manager.acquire(
                    resource_id=resource_id,
                    session_id=session_id,
                    resource_type=ResourceType.TTS_INSTANCE,
                    cleanup_callback=self._cleanup_tts_instance
                )

                if not tts_instance:
                    # No TTS available
                    await self._handle_no_tts(session_id, text, is_welcome)
                    return

                # Create session
                tts_session = TTSSession(session_id, tts_instance)

                # Get locale from event data or default
                locale = event.data.get("locale", "tr")
                tts_session.preprocessor = TTSPreprocessor(language=locale)

                self.tts_sessions[session_id] = tts_session
            else:
                tts_session = self.tts_sessions[session_id]

            # Create job
            job_id = f"{session_id}_{tts_session.total_jobs}"
            job = TTSJob(job_id, session_id, text, is_welcome)
            tts_session.active_jobs[job_id] = job
            tts_session.total_jobs += 1
            tts_session.total_chars += len(text)
            tts_session.update_activity()

            # Process TTS
            await self._process_tts_job(tts_session, job)

        except Exception as e:
            log_error(
                f"❌ Failed to start TTS",
                session_id=session_id,
                error=str(e),
                traceback=traceback.format_exc()
            )

            # Publish error event
            await publish_error(
                session_id=session_id,
                error_type="tts_error",
                error_message=f"Failed to synthesize speech: {str(e)}"
            )

    async def _process_tts_job(self, tts_session: TTSSession, job: TTSJob):
        """Process a TTS job"""
        try:
            # Preprocess text
            processed_text = tts_session.preprocessor.preprocess(
                job.text,
                tts_session.tts_instance.get_preprocessing_flags()
            )

            log_debug(
                f"📝 TTS preprocessed",
                session_id=job.session_id,
                original_length=len(job.text),
                processed_length=len(processed_text)
            )

            # Synthesize audio
            audio_data = await tts_session.tts_instance.synthesize(processed_text)

            if not audio_data:
                raise ValueError("TTS returned empty audio data")

            job.complete(audio_data)

            log_info(
                f"✅ TTS synthesis complete",
                session_id=job.session_id,
                audio_size=len(audio_data),
                duration_ms=(datetime.utcnow() - job.created_at).total_seconds() * 1000
            )

            # Stream audio chunks
            await self._stream_audio_chunks(tts_session, job)

            # Move to completed
            tts_session.active_jobs.pop(job.job_id, None)
            tts_session.completed_jobs.append(job)

            # Keep only last 10 completed jobs
            if len(tts_session.completed_jobs) > 10:
                tts_session.completed_jobs.pop(0)

        except Exception as e:
            job.fail(str(e))

            # Handle specific TTS errors
            error_message = str(e)
            if "quota" in error_message.lower() or "limit" in error_message.lower():
                log_error(f"❌ TTS quota exceeded", session_id=job.session_id)
                await publish_error(
                    session_id=job.session_id,
                    error_type="tts_quota_exceeded",
                    error_message="TTS service quota exceeded"
                )
            else:
                log_error(
                    f"❌ TTS synthesis failed",
                    session_id=job.session_id,
                    error=error_message
                )
                await publish_error(
                    session_id=job.session_id,
                    error_type="tts_error",
                    error_message=error_message
                )

    async def _stream_audio_chunks(self, tts_session: TTSSession, job: TTSJob):
        """Stream audio data as chunks"""
        if not job.audio_data:
            return

        # Convert to base64
        audio_base64 = base64.b64encode(job.audio_data).decode('utf-8')
        total_length = len(audio_base64)
        total_chunks = (total_length + self.chunk_size - 1) // self.chunk_size

        log_debug(
            f"📤 Streaming TTS audio",
            session_id=job.session_id,
            total_size=len(job.audio_data),
            base64_size=total_length,
            chunks=total_chunks
        )

        # Stream chunks
        for i in range(0, total_length, self.chunk_size):
            chunk = audio_base64[i:i + self.chunk_size]
            chunk_index = i // self.chunk_size
            is_last = chunk_index == total_chunks - 1

            await self.event_bus.publish(Event(
                type=EventType.TTS_CHUNK_READY,
                session_id=job.session_id,
                data={
                    "audio_data": chunk,
                    "chunk_index": chunk_index,
                    "total_chunks": total_chunks,
                    "is_last": is_last,
                    "mime_type": "audio/mpeg",
                    "is_welcome": job.is_welcome
                },
                priority=8  # Higher priority for audio chunks
            ))

            job.chunks_sent += 1

            # Small delay between chunks to prevent overwhelming
            await asyncio.sleep(0.01)

        # Notify completion
        await self.event_bus.publish(Event(
            type=EventType.TTS_COMPLETED,
            session_id=job.session_id,
            data={
                "job_id": job.job_id,
                "total_chunks": total_chunks,
                "is_welcome": job.is_welcome
            }
        ))

        log_info(
            f"✅ TTS streaming complete",
            session_id=job.session_id,
            chunks_sent=job.chunks_sent
        )

    async def _handle_no_tts(self, session_id: str, text: str, is_welcome: bool):
        """Handle case when TTS is not available"""
        log_warning(f"⚠️ No TTS available, skipping audio generation", session_id=session_id)

        # Just notify completion without audio
        await self.event_bus.publish(Event(
            type=EventType.TTS_COMPLETED,
            session_id=session_id,
            data={
                "no_audio": True,
                "text": text,
                "is_welcome": is_welcome
            }
        ))

    async def _handle_session_ended(self, event: Event):
        """Clean up TTS resources when session ends"""
        session_id = event.session_id
        await self._cleanup_session(session_id)

    async def _cleanup_session(self, session_id: str):
        """Clean up TTS session"""
        tts_session = self.tts_sessions.pop(session_id, None)
        if not tts_session:
            return

        try:
            # Cancel any active jobs
            for job in tts_session.active_jobs.values():
                if not job.completed_at:
                    job.fail("Session ended")

            # Release resource
            resource_id = f"tts_{session_id}"
            await self.resource_manager.release(resource_id, delay_seconds=120)

            log_info(
                f"🧹 TTS session cleaned up",
                session_id=session_id,
                total_jobs=tts_session.total_jobs,
                total_chars=tts_session.total_chars
            )

        except Exception as e:
            log_error(
                f"❌ Error cleaning up TTS session",
                session_id=session_id,
                error=str(e)
            )

    async def _cleanup_tts_instance(self, tts_instance: TTSInterface):
        """Cleanup callback for TTS instance"""
        try:
            # TTS instances typically don't need special cleanup
            log_debug("🧹 TTS instance cleaned up")

        except Exception as e:
            log_error(f"❌ Error cleaning up TTS instance", error=str(e))

    def get_stats(self) -> Dict[str, Any]:
        """Get TTS manager statistics"""
        session_stats = {}
        for session_id, tts_session in self.tts_sessions.items():
            session_stats[session_id] = {
                "active_jobs": len(tts_session.active_jobs),
                "completed_jobs": len(tts_session.completed_jobs),
                "total_jobs": tts_session.total_jobs,
                "total_chars": tts_session.total_chars,
                "uptime_seconds": (datetime.utcnow() - tts_session.created_at).total_seconds(),
                "last_activity": tts_session.last_activity.isoformat()
            }

        return {
            "active_sessions": len(self.tts_sessions),
            "total_active_jobs": sum(len(s.active_jobs) for s in self.tts_sessions.values()),
            "sessions": session_stats
        }