"""
State Orchestrator for Flare Realtime Chat
==========================================
Central state machine and flow control
"""
import asyncio
from typing import Dict, Optional, Set, Any
from enum import Enum
from datetime import datetime
import traceback
from dataclasses import dataclass, field

from .event_bus import EventBus, Event, EventType, publish_state_transition, publish_error
from .session import Session
from utils.logger import log_info, log_error, log_debug, log_warning


class ConversationState(Enum):
    """Conversation states"""
    IDLE = "idle"
    INITIALIZING = "initializing"
    PREPARING_WELCOME = "preparing_welcome"
    PLAYING_WELCOME = "playing_welcome"
    LISTENING = "listening"
    PROCESSING_SPEECH = "processing_speech"
    PREPARING_RESPONSE = "preparing_response"
    PLAYING_RESPONSE = "playing_response"
    ERROR = "error"
    ENDED = "ended"


@dataclass
class SessionContext:
    """Context for a conversation session"""
    session_id: str
    session: Session
    state: ConversationState = ConversationState.IDLE
    stt_instance: Optional[Any] = None
    tts_instance: Optional[Any] = None
    llm_context: Optional[Any] = None
    audio_buffer: Optional[Any] = None
    websocket_connection: Optional[Any] = None
    created_at: datetime = field(default_factory=datetime.utcnow)
    last_activity: datetime = field(default_factory=datetime.utcnow)
    metadata: Dict[str, Any] = field(default_factory=dict)

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

    async def cleanup(self):
        """Cleanup all session resources"""
        # Cleanup will be implemented by resource managers
        log_debug(f"🧹 Cleaning up session context", session_id=self.session_id)


class StateOrchestrator:
    """Central state machine for conversation flow"""

    # Valid state transitions
    VALID_TRANSITIONS = {
        ConversationState.IDLE: {ConversationState.INITIALIZING},
        ConversationState.INITIALIZING: {ConversationState.PREPARING_WELCOME, ConversationState.LISTENING},
        ConversationState.PREPARING_WELCOME: {ConversationState.PLAYING_WELCOME, ConversationState.ERROR},
        ConversationState.PLAYING_WELCOME: {ConversationState.LISTENING, ConversationState.ERROR},
        ConversationState.LISTENING: {ConversationState.PROCESSING_SPEECH, ConversationState.ERROR, ConversationState.ENDED},
        ConversationState.PROCESSING_SPEECH: {ConversationState.PREPARING_RESPONSE, ConversationState.ERROR},
        ConversationState.PREPARING_RESPONSE: {ConversationState.PLAYING_RESPONSE, ConversationState.ERROR},
        ConversationState.PLAYING_RESPONSE: {ConversationState.LISTENING, ConversationState.ERROR},
        ConversationState.ERROR: {ConversationState.LISTENING, ConversationState.ENDED},
        ConversationState.ENDED: set()  # No transitions from ENDED
    }

    def __init__(self, event_bus: EventBus):
        self.event_bus = event_bus
        self.sessions: Dict[str, SessionContext] = {}
        self._setup_event_handlers()

    def _setup_event_handlers(self):
        """Subscribe to relevant events"""

        # Conversation events
        self.event_bus.subscribe(EventType.CONVERSATION_STARTED, self._handle_conversation_started)
        self.event_bus.subscribe(EventType.CONVERSATION_ENDED, self._handle_conversation_ended)

        # Session lifecycle
        self.event_bus.subscribe(EventType.SESSION_STARTED, self._handle_session_started)
        self.event_bus.subscribe(EventType.SESSION_ENDED, self._handle_session_ended)

        # ✅ WebSocket events
        self.event_bus.subscribe(EventType.WEBSOCKET_DISCONNECTED, self._handle_websocket_disconnected)
        
        # STT events
        self.event_bus.subscribe(EventType.STT_READY, self._handle_stt_ready)
        self.event_bus.subscribe(EventType.STT_RESULT, self._handle_stt_result)
        self.event_bus.subscribe(EventType.STT_ERROR, self._handle_stt_error)

        # TTS events
        self.event_bus.subscribe(EventType.TTS_COMPLETED, self._handle_tts_completed)
        self.event_bus.subscribe(EventType.TTS_ERROR, self._handle_tts_error)

        # Audio events
        self.event_bus.subscribe(EventType.AUDIO_PLAYBACK_COMPLETED, self._handle_audio_playback_completed)

        # LLM events
        self.event_bus.subscribe(EventType.LLM_RESPONSE_READY, self._handle_llm_response_ready)
        self.event_bus.subscribe(EventType.LLM_ERROR, self._handle_llm_error)

        # Error events
        self.event_bus.subscribe(EventType.CRITICAL_ERROR, self._handle_critical_error)

    async def _handle_websocket_disconnected(self, event: Event):
        """Handle WebSocket disconnection"""
        session_id = event.session_id
        context = self.sessions.get(session_id)
        
        if not context:
            return
            
        log_info(f"🔌 Handling WebSocket disconnect | session_id={session_id}, state={context.state.value}")
        
        # Eğer conversation aktifse, önce conversation'ı sonlandır
        if context.state not in [ConversationState.IDLE, ConversationState.ENDED]:
            await self._handle_conversation_ended(Event(
                type=EventType.CONVERSATION_ENDED,
                session_id=session_id,
                data={"reason": "websocket_disconnected"}
            ))
            
    async def _handle_conversation_started(self, event: Event) -> None:
        """Handle conversation start within existing session"""
        session_id = event.session_id
        context = self.sessions.get(session_id)

        if not context:
            log_error(f"❌ Session not found for conversation start | session_id={session_id}")
            return

        log_info(f"🎤 Conversation started | session_id={session_id}")

        # İlk olarak IDLE'dan INITIALIZING'e geç
        await self.transition_to(session_id, ConversationState.INITIALIZING)

        # Welcome mesajı varsa
        if context.metadata.get("has_welcome") and context.metadata.get("welcome_text"):
            await self.transition_to(session_id, ConversationState.PREPARING_WELCOME)

            # Request TTS for welcome message
            await self.event_bus.publish(Event(
                type=EventType.TTS_STARTED,
                session_id=session_id,
                data={
                    "text": context.metadata.get("welcome_text", ""),
                    "is_welcome": True
                }
            ))
        else:
            # Welcome yoksa direkt LISTENING'e geç
            await self.transition_to(session_id, ConversationState.LISTENING)

            # Start STT
            await self.event_bus.publish(
                Event(
                    type=EventType.STT_STARTED,
                    data={},
                    session_id=session_id
                )
            )

    async def _handle_conversation_ended(self, event: Event) -> None:
        """Handle conversation end - but keep session alive"""
        session_id = event.session_id
        context = self.sessions.get(session_id)

        if not context:
            log_warning(f"⚠️ Session not found for conversation end | session_id={session_id}")
            return

        log_info(f"🔚 Conversation ended | session_id={session_id}")

        # Stop STT if running
        await self.event_bus.publish(Event(
            type=EventType.STT_STOPPED,
            session_id=session_id,
            data={"reason": "conversation_ended"}
        ))

        # Stop any ongoing TTS
        await self.event_bus.publish(Event(
            type=EventType.TTS_STOPPED,
            session_id=session_id,
            data={"reason": "conversation_ended"}
        ))

        # Transition back to IDLE - session still alive!
        await self.transition_to(session_id, ConversationState.IDLE)

        log_info(f"💤 Session back to IDLE, ready for new conversation | session_id={session_id}")

    async def _handle_session_started(self, event: Event):
        """Handle session start"""
        session_id = event.session_id
        session_data = event.data

        log_info(f"🎬 Session started", session_id=session_id)

        # Create session context
        context = SessionContext(
            session_id=session_id,
            session=session_data.get("session"),
            metadata={
                "has_welcome": session_data.get("has_welcome", False),
                "welcome_text": session_data.get("welcome_text", "")
            }
        )

        self.sessions[session_id] = context

        # Session başladığında IDLE state'te kalmalı
        # Conversation başlayana kadar bekleyeceğiz
        # Zaten SessionContext default state'i IDLE
        log_info(f"📍 Session created in IDLE state | session_id={session_id}")

    async def _handle_session_ended(self, event: Event):
        """Handle session end - complete cleanup"""
        session_id = event.session_id

        log_info(f"🏁 Session ended | session_id={session_id}")

        # Get context for cleanup
        context = self.sessions.get(session_id)

        if context:
            # Try to transition to ENDED if possible
            try:
                await self.transition_to(session_id, ConversationState.ENDED)
            except Exception as e:
                log_warning(f"Could not transition to ENDED state: {e}")

            # Stop all components
            await self.event_bus.publish(Event(
                type=EventType.STT_STOPPED,
                session_id=session_id,
                data={"reason": "session_ended"}
            ))

            await self.event_bus.publish(Event(
                type=EventType.TTS_STOPPED,
                session_id=session_id,
                data={"reason": "session_ended"}
            ))

            # Cleanup session context
            await context.cleanup()

        # Remove session
        self.sessions.pop(session_id, None)

        # Clear event bus session data
        self.event_bus.clear_session_data(session_id)

        log_info(f"✅ Session fully cleaned up | session_id={session_id}")

    async def _handle_stt_ready(self, event: Event):
        """Handle STT ready signal"""
        session_id = event.session_id
        current_state = self.get_state(session_id)

        log_debug(f"🎤 STT ready", session_id=session_id, current_state=current_state)

        # Only process if we're expecting STT to be ready
        if current_state in [ConversationState.LISTENING, ConversationState.PLAYING_WELCOME]:
            # STT is ready, we're already in the right state
            pass

    async def _handle_stt_result(self, event: Event):
        """Handle STT transcription result"""
        session_id = event.session_id
        context = self.sessions.get(session_id)
    
        if not context:
            return
    
        current_state = context.state
        result_data = event.data
        
        # Batch mode'da her zaman final result gelir
        text = result_data.get("text", "").strip()
        
        if current_state != ConversationState.LISTENING:
            log_warning(
                f"⚠️ STT result in unexpected state",
                session_id=session_id,
                state=current_state.value
            )
            return
    
        if text:
            log_info(f"💬 Transcription: '{text}'", session_id=session_id)
        else:
            log_info(f"💬 No speech detected", session_id=session_id)
            # Boş transcript'te STT'yi yeniden başlat
            await self.event_bus.publish(Event(
                type=EventType.STT_STARTED,
                session_id=session_id,
                data={}
            ))
            return
    
        # Transition to processing
        await self.transition_to(session_id, ConversationState.PROCESSING_SPEECH)
    
        # Send to LLM
        await self.event_bus.publish(Event(
            type=EventType.LLM_PROCESSING_STARTED,
            session_id=session_id,
            data={"text": text}
        ))
        
    async def _handle_llm_response_ready(self, event: Event):
        """Handle LLM response"""
        session_id = event.session_id
        current_state = self.get_state(session_id)

        # Debug için context'i direkt alalım
        context = self.sessions.get(session_id)
        if not context:
            log_error(f"❌ No context for LLM response", session_id=session_id)
            return
            
        current_state = context.state
        log_debug(f"🔍 LLM response handler - current state: {current_state.value}")
        
        if current_state != ConversationState.PROCESSING_SPEECH:
            log_warning(
                f"⚠️ LLM response in unexpected state",
                session_id=session_id,
                state=current_state
            )
            return

        response_text = event.data.get("text", "")
        log_info(f"🤖 LLM response ready", session_id=session_id, length=len(response_text))

        # Transition to preparing response
        await self.transition_to(session_id, ConversationState.PREPARING_RESPONSE)

        # Request TTS
        await self.event_bus.publish(Event(
            type=EventType.TTS_STARTED,
            session_id=session_id,
            data={"text": response_text}
        ))

    async def _handle_tts_completed(self, event: Event):
        """Handle TTS completion"""
        session_id = event.session_id
        context = self.sessions.get(session_id)

        if not context:
            return

        current_state = context.state

        log_info(f"🔊 TTS completed", session_id=session_id, state=current_state.value)

        if current_state == ConversationState.PREPARING_WELCOME:
            await self.transition_to(session_id, ConversationState.PLAYING_WELCOME)

            # Welcome audio frontend'te çalınacak, biz sadece state'i güncelliyoruz
            # Frontend audio bitince bize audio_playback_completed gönderecek

        elif current_state == ConversationState.PREPARING_RESPONSE:
            await self.transition_to(session_id, ConversationState.PLAYING_RESPONSE)

    async def _handle_audio_playback_completed(self, event: Event):
        """Handle audio playback completion"""
        session_id = event.session_id
        context = self.sessions.get(session_id)
    
        if not context:
            return
    
        current_state = context.state
    
        log_info(f"🎵 Audio playback completed", session_id=session_id, state=current_state.value)
    
        if current_state in [ConversationState.PLAYING_WELCOME, ConversationState.PLAYING_RESPONSE]:
            # Transition to listening
            await self.transition_to(session_id, ConversationState.LISTENING)
    
            # ✅ STT'yi başlat - batch mode için yeni utterance
            locale = context.metadata.get("locale", "tr")
            await self.event_bus.publish(Event(
                type=EventType.STT_STARTED,
                session_id=session_id,
                data={
                    "locale": locale,
                    "batch_mode": True,  # ✅ Batch mode aktif
                    "silence_threshold_ms": 1000  # 1 saniye sessizlik
                }
            ))
    
            # Send STT ready signal to frontend
            await self.event_bus.publish(Event(
                type=EventType.STT_READY,
                session_id=session_id,
                data={}
            ))

    async def _handle_stt_error(self, event: Event):
        """Handle STT errors"""
        session_id = event.session_id
        error_data = event.data

        log_error(
            f"❌ STT error",
            session_id=session_id,
            error=error_data.get("message")
        )

        # Try to recover by transitioning back to listening
        current_state = self.get_state(session_id)
        if current_state != ConversationState.ENDED:
            await self.transition_to(session_id, ConversationState.ERROR)

            # Try recovery after delay
            await asyncio.sleep(2.0)

            if self.get_state(session_id) == ConversationState.ERROR:
                await self.transition_to(session_id, ConversationState.LISTENING)

                # Restart STT
                await self.event_bus.publish(Event(
                    type=EventType.STT_STARTED,
                    session_id=session_id,
                    data={"retry": True}
                ))

    async def _handle_tts_error(self, event: Event):
        """Handle TTS errors"""
        session_id = event.session_id
        error_data = event.data

        log_error(
            f"❌ TTS error",
            session_id=session_id,
            error=error_data.get("message")
        )

        # Skip TTS and go to listening
        current_state = self.get_state(session_id)
        if current_state in [ConversationState.PREPARING_WELCOME, ConversationState.PREPARING_RESPONSE]:
            await self.transition_to(session_id, ConversationState.LISTENING)

            # Start STT
            await self.event_bus.publish(Event(
                type=EventType.STT_STARTED,
                session_id=session_id,
                data={}
            ))

    async def _handle_llm_error(self, event: Event):
        """Handle LLM errors"""
        session_id = event.session_id
        error_data = event.data

        log_error(
            f"❌ LLM error",
            session_id=session_id,
            error=error_data.get("message")
        )

        # Go back to listening
        await self.transition_to(session_id, ConversationState.LISTENING)

        # Start STT
        await self.event_bus.publish(Event(
            type=EventType.STT_STARTED,
            session_id=session_id,
            data={}
        ))

    async def _handle_critical_error(self, event: Event):
        """Handle critical errors"""
        session_id = event.session_id
        error_data = event.data

        log_error(
            f"💥 Critical error",
            session_id=session_id,
            error=error_data.get("message")
        )

        # End session
        await self.transition_to(session_id, ConversationState.ENDED)

        # Publish session end event
        await self.event_bus.publish(Event(
            type=EventType.SESSION_ENDED,
            session_id=session_id,
            data={"reason": "critical_error"}
        ))

    async def transition_to(self, session_id: str, new_state: ConversationState) -> bool:
        """
        Transition to a new state with validation
        """
        try:
            # Get session context
            context = self.sessions.get(session_id)
            if not context:
                log_info(f"❌ Session not found for state transition | session_id={session_id}")
                return False

            # Get current state from context
            current_state = context.state

            # Check if transition is valid
            if new_state not in self.VALID_TRANSITIONS.get(current_state, set()):
                log_info(f"❌ Invalid state transition | session_id={session_id}, current={current_state.value}, requested={new_state.value}")
                return False

            # Update state
            old_state = current_state
            context.state = new_state
            context.last_activity = datetime.utcnow()

            log_info(f"✅ State transition | session_id={session_id}, {old_state.value} → {new_state.value}")

            # Emit state transition event with correct field names
            await self.event_bus.publish(
                Event(
                    type=EventType.STATE_TRANSITION,
                    data={
                        "old_state": old_state.value,  # Backend uses old_state/new_state
                        "new_state": new_state.value,
                        "timestamp": datetime.utcnow().isoformat()
                    },
                    session_id=session_id
                )
            )

            return True

        except Exception as e:
            log_error(f"❌ State transition error | session_id={session_id}", e)
            return False

    def get_state(self, session_id: str) -> Optional[ConversationState]:
        """Get current state for a session"""
        return self.sessions.get(session_id)

    def get_session_data(self, session_id: str) -> Optional[Dict[str, Any]]:
        """Get session data"""
        return self.session_data.get(session_id)

    async def handle_error_recovery(self, session_id: str, error_type: str):
        """Handle error recovery strategies"""
        context = self.sessions.get(session_id)

        if not context or context.state == ConversationState.ENDED:
            return

        log_info(
            f"🔧 Attempting error recovery",
            session_id=session_id,
            error_type=error_type,
            current_state=context.state.value
        )

        # Update activity
        context.update_activity()

        # Define recovery strategies
        recovery_strategies = {
            "stt_error": self._recover_from_stt_error,
            "tts_error": self._recover_from_tts_error,
            "llm_error": self._recover_from_llm_error,
            "websocket_error": self._recover_from_websocket_error
        }

        strategy = recovery_strategies.get(error_type)
        if strategy:
            await strategy(session_id)
        else:
            # Default recovery: go to error state then back to listening
            await self.transition_to(session_id, ConversationState.ERROR)
            await asyncio.sleep(1.0)
            await self.transition_to(session_id, ConversationState.LISTENING)

    async def _recover_from_stt_error(self, session_id: str):
        """Recover from STT error"""
        # Stop STT, wait, restart
        await self.event_bus.publish(Event(
            type=EventType.STT_STOPPED,
            session_id=session_id,
            data={"reason": "error_recovery"}
        ))

        await asyncio.sleep(2.0)

        await self.transition_to(session_id, ConversationState.LISTENING)

        await self.event_bus.publish(Event(
            type=EventType.STT_STARTED,
            session_id=session_id,
            data={"retry": True}
        ))

    async def _recover_from_tts_error(self, session_id: str):
        """Recover from TTS error"""
        # Skip TTS, go directly to listening
        await self.transition_to(session_id, ConversationState.LISTENING)

        await self.event_bus.publish(Event(
            type=EventType.STT_STARTED,
            session_id=session_id,
            data={}
        ))

    async def _recover_from_llm_error(self, session_id: str):
        """Recover from LLM error"""
        # Go back to listening
        await self.transition_to(session_id, ConversationState.LISTENING)

        await self.event_bus.publish(Event(
            type=EventType.STT_STARTED,
            session_id=session_id,
            data={}
        ))

    async def _recover_from_websocket_error(self, session_id: str):
        """Recover from WebSocket error"""
        # End session cleanly
        await self.transition_to(session_id, ConversationState.ENDED)

        await self.event_bus.publish(Event(
            type=EventType.SESSION_ENDED,
            session_id=session_id,
            data={"reason": "websocket_error"}
        ))