/**
 * useLiveKitRoom - Hook for LiveKit voice call with Julia AI
 *
 * IMPORTANT: This hook encapsulates ALL LiveKit logic.
 * The UI component should only use the returned state and actions.
 *
 * LOGGING: Maximum transparency - every step is logged!
 */

import { useState, useCallback, useRef, useEffect } from 'react';
import { Platform, AppState, AppStateStatus, NativeModules } from 'react-native';
import type { Room as RoomType } from 'livekit-client';

// Helper to detect iOS Simulator
// Expo Go and production builds both work with this approach
const isIOSSimulator = (): boolean => {
  if (Platform.OS !== 'ios') return false;
  // Check via DeviceInfo module if available
  const { PlatformConstants } = NativeModules;
  return PlatformConstants?.interfaceIdiom === 'simulator' ||
         PlatformConstants?.isSimulator === true;
};
import { getToken, VOICE_NAME } from '@/services/livekitService';
import {
  configureAudioForVoiceCall,
  stopAudioSession,
  reconfigureAudioForPlayback,
} from '@/utils/audioSession';

// Connection states
export type ConnectionState =
  | 'idle'
  | 'initializing'
  | 'configuring_audio'
  | 'requesting_token'
  | 'connecting'
  | 'connected'
  | 'reconnecting'
  | 'disconnecting'
  | 'disconnected'
  | 'error';

// Log entry type
export interface LogEntry {
  timestamp: string; // Formatted time string (HH:MM:SS.mmm)
  level: 'info' | 'warn' | 'error' | 'success';
  message: string;
}

// Hook options
export interface UseLiveKitRoomOptions {
  userId: string;
  onTranscript?: (role: 'user' | 'assistant', text: string) => void;
  autoConnect?: boolean;
}

// Hook return type
export interface UseLiveKitRoomReturn {
  // Connection state
  state: ConnectionState;
  error: string | null;

  // Call info
  roomName: string | null;
  callDuration: number;

  // Audio state
  isMuted: boolean;
  isAgentSpeaking: boolean;
  canPlayAudio: boolean;

  // Debug info
  logs: LogEntry[];
  participantCount: number;

  // Actions
  connect: () => Promise<void>;
  disconnect: () => Promise<void>;
  toggleMute: () => Promise<void>;
  clearLogs: () => void;
}

/**
 * Main hook for LiveKit voice calls
 */
export function useLiveKitRoom(options: UseLiveKitRoomOptions): UseLiveKitRoomReturn {
  const { userId, onTranscript, autoConnect = false } = options;

  // State
  const [state, setState] = useState<ConnectionState>('idle');
  const [error, setError] = useState<string | null>(null);
  const [roomName, setRoomName] = useState<string | null>(null);
  const [callDuration, setCallDuration] = useState(0);
  const [isMuted, setIsMuted] = useState(false);
  const [isAgentSpeaking, setIsAgentSpeaking] = useState(false);
  const [canPlayAudio, setCanPlayAudio] = useState(false);
  const [logs, setLogs] = useState<LogEntry[]>([]);
  const [participantCount, setParticipantCount] = useState(0);

  // Refs
  const roomRef = useRef<RoomType | null>(null);
  const callStartTimeRef = useRef<number | null>(null);
  const connectionIdRef = useRef(0);
  const isUnmountingRef = useRef(false);
  const appStateRef = useRef<AppStateStatus>(AppState.currentState);

  // ===================
  // LOGGING FUNCTIONS
  // ===================

  const log = useCallback((level: LogEntry['level'], message: string) => {
    const now = new Date();
    const timestamp = now.toLocaleTimeString('en-US', {
      hour12: false,
      hour: '2-digit',
      minute: '2-digit',
      second: '2-digit',
    }) + '.' + now.getMilliseconds().toString().padStart(3, '0');

    const entry: LogEntry = {
      timestamp,
      level,
      message,
    };
    setLogs((prev) => [...prev, entry]);

    // Also log to console with color
    const prefix = `[LiveKit ${timestamp}]`;
    switch (level) {
      case 'error':
        console.error(`${prefix} ERROR: ${message}`);
        break;
      case 'warn':
        console.warn(`${prefix} WARN: ${message}`);
        break;
      case 'success':
        console.log(`${prefix} SUCCESS: ${message}`);
        break;
      default:
        console.log(`${prefix} INFO: ${message}`);
    }
  }, []);

  const logInfo = useCallback((msg: string) => log('info', msg), [log]);
  const logWarn = useCallback((msg: string) => log('warn', msg), [log]);
  const logError = useCallback((msg: string) => log('error', msg), [log]);
  const logSuccess = useCallback((msg: string) => log('success', msg), [log]);

  const clearLogs = useCallback(() => {
    setLogs([]);
  }, []);

  // ===================
  // CONNECT FUNCTION
  // ===================

  const connect = useCallback(async () => {
    // Prevent multiple concurrent connection attempts
    const currentConnectionId = ++connectionIdRef.current;

    logInfo('========== STARTING VOICE CALL ==========');
    logInfo(`User ID: ${userId}`);
    logInfo(`Platform: ${Platform.OS}`);
    logInfo(`Connection ID: ${currentConnectionId}`);

    // Check if already connected
    if (roomRef.current) {
      logWarn('Already connected to a room, disconnecting first...');
      await roomRef.current.disconnect();
      roomRef.current = null;
    }

    try {
      // ========== STEP 1: Initialize ==========
      setState('initializing');
      logInfo('STEP 1/6: Initializing...');

      // Detect simulator vs real device
      const isSimulator = isIOSSimulator();
      logInfo(`Device type: ${isSimulator ? 'SIMULATOR' : 'REAL DEVICE'}`);
      logInfo(`Device model: ${Platform.OS} ${Platform.Version}`);

      if (isSimulator) {
        logWarn('⚠️ SIMULATOR DETECTED - Microphone will NOT work!');
        logWarn('Simulator can only test: connection, token, agent presence, TTS playback');
        logWarn('For full STT test, use a real iPhone device');
      }

      // Check if connection was cancelled
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled (component unmounting or new connection started)');
        return;
      }

      // ========== STEP 2: Register WebRTC Globals ==========
      logInfo('STEP 2/6: Registering WebRTC globals...');

      const { registerGlobals } = await import('@livekit/react-native');

      if (typeof global.RTCPeerConnection === 'undefined') {
        logInfo('RTCPeerConnection not found, calling registerGlobals()...');
        registerGlobals();
        logSuccess('WebRTC globals registered!');
      } else {
        logInfo('WebRTC globals already registered');
      }

      // Check again
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled after registerGlobals');
        return;
      }

      // ========== STEP 3: Configure iOS Audio ==========
      setState('configuring_audio');
      logInfo('STEP 3/6: Configuring iOS AudioSession...');

      await configureAudioForVoiceCall();
      logSuccess('iOS AudioSession configured!');

      // Check again
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled after audio config');
        await stopAudioSession();
        return;
      }

      // ========== STEP 4: Get Token ==========
      setState('requesting_token');
      logInfo('STEP 4/6: Requesting token from server...');

      const tokenResult = await getToken(userId);

      if (!tokenResult.success || !tokenResult.data) {
        const errorMsg = tokenResult.error || 'Failed to get token';
        logError(`Token request failed: ${errorMsg}`);
        setError(errorMsg);
        setState('error');
        return;
      }

      const { token, wsUrl, roomName: room } = tokenResult.data;
      setRoomName(room);

      logSuccess(`Token received!`);
      logInfo(`  Room: ${room}`);
      logInfo(`  WebSocket URL: ${wsUrl}`);
      logInfo(`  Token length: ${token.length} chars`);

      // Check again
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled after token');
        await stopAudioSession();
        return;
      }

      // ========== STEP 5: Import LiveKit and Create Room ==========
      logInfo('STEP 5/6: Creating LiveKit Room...');

      const { Room, RoomEvent, ConnectionState: LKConnectionState, Track } = await import(
        'livekit-client'
      );

      logInfo(`  Room class available: ${typeof Room === 'function'}`);
      logInfo(`  RoomEvent available: ${typeof RoomEvent === 'object'}`);

      const lkRoom = new Room();
      roomRef.current = lkRoom;

      logSuccess('Room instance created!');

      // ========== Setup Event Listeners ==========
      logInfo('Setting up event listeners...');

      // Connection state changes
      lkRoom.on(RoomEvent.ConnectionStateChanged, (newState) => {
        logInfo(`EVENT: ConnectionStateChanged -> ${newState}`);

        switch (newState) {
          case LKConnectionState.Connecting:
            setState('connecting');
            break;
          case LKConnectionState.Connected:
            setState('connected');
            logSuccess('Connected to room!');
            if (!callStartTimeRef.current) {
              callStartTimeRef.current = Date.now();
              logInfo('Call timer started');
            }
            break;
          case LKConnectionState.Reconnecting:
            setState('reconnecting');
            logWarn('Reconnecting...');
            break;
          case LKConnectionState.Disconnected:
            setState('disconnected');
            logInfo('Disconnected from room');
            break;
        }
      });

      // Track subscribed (audio from agent)
      lkRoom.on(RoomEvent.TrackSubscribed, async (track, publication, participant) => {
        logInfo(`EVENT: TrackSubscribed`);
        logInfo(`  Track kind: ${track.kind}`);
        logInfo(`  Track source: ${track.source}`);
        logInfo(`  Participant: ${participant.identity}`);
        logInfo(`  Publication SID: ${publication.trackSid}`);

        if (track.kind === Track.Kind.Audio) {
          logSuccess(`Audio track from ${participant.identity} - should hear voice now!`);
          setIsAgentSpeaking(true);

          // Reconfigure audio for playback
          logInfo('Reconfiguring audio for playback...');
          await reconfigureAudioForPlayback();
        }
      });

      // Track unsubscribed
      lkRoom.on(RoomEvent.TrackUnsubscribed, (track, publication, participant) => {
        logInfo(`EVENT: TrackUnsubscribed`);
        logInfo(`  Track kind: ${track.kind}`);
        logInfo(`  Participant: ${participant.identity}`);

        if (track.kind === Track.Kind.Audio) {
          setIsAgentSpeaking(false);
        }
      });

      // Track muted/unmuted
      lkRoom.on(RoomEvent.TrackMuted, (publication, participant) => {
        logInfo(`EVENT: TrackMuted - ${publication.trackSid} by ${participant.identity}`);
      });

      lkRoom.on(RoomEvent.TrackUnmuted, (publication, participant) => {
        logInfo(`EVENT: TrackUnmuted - ${publication.trackSid} by ${participant.identity}`);
      });

      // Participants
      lkRoom.on(RoomEvent.ParticipantConnected, (participant) => {
        logSuccess(`EVENT: ParticipantConnected - ${participant.identity}`);
        setParticipantCount((c) => c + 1);
      });

      lkRoom.on(RoomEvent.ParticipantDisconnected, (participant) => {
        logInfo(`EVENT: ParticipantDisconnected - ${participant.identity}`);
        setParticipantCount((c) => Math.max(0, c - 1));
      });

      // Active speakers (voice activity)
      lkRoom.on(RoomEvent.ActiveSpeakersChanged, (speakers) => {
        if (speakers.length > 0) {
          const speakerNames = speakers.map((s: any) => s.identity).join(', ');
          logInfo(`EVENT: ActiveSpeakersChanged - ${speakerNames}`);

          // Check if agent is speaking
          const agentSpeaking = speakers.some((s: any) => s.identity.startsWith('agent'));
          setIsAgentSpeaking(agentSpeaking);
        }
      });

      // Local track published (our mic)
      lkRoom.on(RoomEvent.LocalTrackPublished, (publication, participant) => {
        logSuccess(`EVENT: LocalTrackPublished`);
        logInfo(`  Track: ${publication.trackSid}`);
        logInfo(`  Kind: ${publication.kind}`);
        logInfo(`  Source: ${publication.source}`);
      });

      // Audio playback status
      lkRoom.on(RoomEvent.AudioPlaybackStatusChanged, () => {
        const canPlay = lkRoom.canPlaybackAudio;
        logInfo(`EVENT: AudioPlaybackStatusChanged - canPlaybackAudio: ${canPlay}`);
        setCanPlayAudio(canPlay);
      });

      // Data received (transcripts)
      lkRoom.on(RoomEvent.DataReceived, (payload, participant) => {
        try {
          const data = JSON.parse(new TextDecoder().decode(payload));
          logInfo(`EVENT: DataReceived from ${participant?.identity || 'unknown'}`);
          logInfo(`  Type: ${data.type}`);

          if (data.type === 'transcript' && onTranscript) {
            logInfo(`  Role: ${data.role}, Text: ${data.text?.substring(0, 50)}...`);
            onTranscript(data.role, data.text);
          }
        } catch (e) {
          // Non-JSON data, ignore
        }
      });

      // Errors
      lkRoom.on(RoomEvent.Disconnected, (reason) => {
        logWarn(`EVENT: Disconnected - Reason: ${reason}`);
      });

      // Check again before connect
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled before room.connect()');
        await stopAudioSession();
        return;
      }

      // ========== STEP 6: Connect to Room ==========
      setState('connecting');
      logInfo('STEP 6/6: Connecting to LiveKit room...');
      logInfo(`  URL: ${wsUrl}`);
      logInfo(`  Room: ${room}`);

      await lkRoom.connect(wsUrl, token, {
        autoSubscribe: true,
      });

      logSuccess('Connected to room!');

      // Check if connection was cancelled after connect
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Connection cancelled after room.connect()');
        await lkRoom.disconnect();
        await stopAudioSession();
        return;
      }

      // ========== Enable Microphone ==========
      logInfo('Enabling microphone...');

      try {
        await lkRoom.localParticipant.setMicrophoneEnabled(true);
        logSuccess('Microphone enabled!');
        logInfo(`  Local participant: ${lkRoom.localParticipant.identity}`);

        // Log track info - CRITICAL for debugging!
        const audioTracks = lkRoom.localParticipant.getTrackPublications();
        logInfo(`  Published tracks: ${audioTracks.length}`);

        let micTrackFound = false;
        audioTracks.forEach((pub) => {
          logInfo(`    - ${pub.kind}: ${pub.trackSid} (${pub.source})`);
          logInfo(`      isMuted: ${pub.isMuted}, isSubscribed: ${pub.isSubscribed}`);

          if (pub.kind === 'audio' && pub.source === 'microphone') {
            micTrackFound = true;
            const track = pub.track;
            if (track) {
              logInfo(`      Track mediaStreamTrack: ${track.mediaStreamTrack?.readyState || 'N/A'}`);
              logInfo(`      Track enabled: ${track.mediaStreamTrack?.enabled || 'N/A'}`);
            } else {
              logWarn(`      WARNING: No track object on publication!`);
            }
          }
        });

        if (!micTrackFound) {
          // Check if simulator
          const isSimulator = isIOSSimulator();
          if (isSimulator) {
            logWarn('No microphone track - EXPECTED on simulator');
            logInfo('Simulator test: check if Agent joined and TTS works');
          } else {
            logError('CRITICAL: No microphone track published! STT will NOT work!');
            logError('Possible causes: permissions denied, AudioSession not configured, hardware issue');
          }
        } else {
          logSuccess('Microphone track found and published - STT should work');
        }

      } catch (micError: any) {
        logError(`Failed to enable microphone: ${micError.message}`);
        logError(`Stack: ${micError.stack || 'N/A'}`);
        // This is CRITICAL - user must know!
        setError(`Microphone error: ${micError.message}`);
      }

      // Set initial participant count
      setParticipantCount(lkRoom.remoteParticipants.size);
      logInfo(`Remote participants: ${lkRoom.remoteParticipants.size}`);

      logSuccess('========== VOICE CALL STARTED ==========');
    } catch (err: any) {
      // Ignore errors if unmounting
      if (isUnmountingRef.current || currentConnectionId !== connectionIdRef.current) {
        logWarn('Error ignored (component unmounting)');
        return;
      }

      const errorMsg = err?.message || String(err);
      logError(`Connection failed: ${errorMsg}`);
      logError(`Stack: ${err?.stack || 'N/A'}`);

      setError(errorMsg);
      setState('error');

      // Cleanup
      await stopAudioSession();
    }
  }, [userId, onTranscript, logInfo, logWarn, logError, logSuccess]);

  // ===================
  // DISCONNECT FUNCTION
  // ===================

  const disconnect = useCallback(async () => {
    logInfo('========== DISCONNECTING ==========');
    setState('disconnecting');

    try {
      if (roomRef.current) {
        logInfo('Disconnecting from room...');
        await roomRef.current.disconnect();
        roomRef.current = null;
        logSuccess('Disconnected from room');
      } else {
        logInfo('No room to disconnect from');
      }
    } catch (err: any) {
      logError(`Disconnect error: ${err.message}`);
    }

    logInfo('Stopping audio session...');
    await stopAudioSession();

    // Reset state
    setState('disconnected');
    setRoomName(null);
    setIsMuted(false);
    setIsAgentSpeaking(false);
    setParticipantCount(0);
    callStartTimeRef.current = null;

    logSuccess('========== DISCONNECTED ==========');
  }, [logInfo, logError, logSuccess]);

  // ===================
  // TOGGLE MUTE
  // ===================

  const toggleMute = useCallback(async () => {
    if (!roomRef.current) {
      logWarn('Cannot toggle mute - not connected');
      return;
    }

    const newMuted = !isMuted;
    logInfo(`Toggling mute: ${isMuted} -> ${newMuted}`);

    try {
      await roomRef.current.localParticipant.setMicrophoneEnabled(!newMuted);
      setIsMuted(newMuted);
      logSuccess(`Microphone ${newMuted ? 'muted' : 'unmuted'}`);
    } catch (err: any) {
      logError(`Failed to toggle mute: ${err.message}`);
    }
  }, [isMuted, logInfo, logWarn, logError, logSuccess]);

  // ===================
  // CALL DURATION TIMER
  // ===================

  useEffect(() => {
    if (state !== 'connected') return;

    const interval = setInterval(() => {
      if (callStartTimeRef.current) {
        const elapsed = Math.floor((Date.now() - callStartTimeRef.current) / 1000);
        setCallDuration(elapsed);
      }
    }, 1000);

    return () => clearInterval(interval);
  }, [state]);

  // ===================
  // APP STATE HANDLING
  // ===================

  useEffect(() => {
    const handleAppStateChange = (nextAppState: AppStateStatus) => {
      const prevState = appStateRef.current;
      appStateRef.current = nextAppState;

      if (prevState.match(/inactive|background/) && nextAppState === 'active') {
        logInfo('App returned to foreground');
      } else if (prevState === 'active' && nextAppState.match(/inactive|background/)) {
        logInfo('App went to background - call continues in background');
      }
    };

    const subscription = AppState.addEventListener('change', handleAppStateChange);
    return () => subscription.remove();
  }, [logInfo]);

  // ===================
  // CLEANUP ON UNMOUNT
  // ===================

  useEffect(() => {
    isUnmountingRef.current = false;

    return () => {
      isUnmountingRef.current = true;

      // Cleanup
      const cleanup = async () => {
        if (roomRef.current) {
          try {
            await roomRef.current.disconnect();
          } catch (e) {
            // Ignore
          }
          roomRef.current = null;
        }
        await stopAudioSession();
      };

      cleanup();
    };
  }, []);

  // ===================
  // AUTO CONNECT
  // ===================

  useEffect(() => {
    if (autoConnect && state === 'idle') {
      connect();
    }
  }, [autoConnect, state, connect]);

  // ===================
  // RETURN
  // ===================

  return {
    // Connection state
    state,
    error,

    // Call info
    roomName,
    callDuration,

    // Audio state
    isMuted,
    isAgentSpeaking,
    canPlayAudio,

    // Debug
    logs,
    participantCount,

    // Actions
    connect,
    disconnect,
    toggleMute,
    clearLogs,
  };
}

export { VOICE_NAME };