/**
 * Voice Context - Local STT/TTS integration with WellNuo API
 *
 * Provides voice session management:
 * - STT (Speech-to-Text) via expo-speech-recognition
 * - API calls to WellNuo ask_wellnuo_ai
 * - TTS (Text-to-Speech) via expo-speech
 *
 * Flow: User speaks → STT → API → Response → TTS → Continue listening
 */

import React, {
  createContext,
  useContext,
  useState,
  useCallback,
  useRef,
  ReactNode,
} from 'react';
import * as Speech from 'expo-speech';
import { api } from '@/services/api';
import { useVoiceTranscript } from './VoiceTranscriptContext';

// WellNuo API configuration (same as chat.tsx)
const API_URL = 'https://eluxnetworks.net/function/well-api/api';
const WELLNUO_USER = 'anandk';
const WELLNUO_PASSWORD = 'anandk_8';

// Single deployment mode - sends only deployment_id (no beneficiary_names_dict)
const SINGLE_DEPLOYMENT_MODE = true;

// Keywords for question normalization (same as chat.tsx)
const STATUS_KEYWORDS = [
  /\bhow\s+is\b/i,
  /\bhow'?s\b/i,
  /\bhow\s+are\b/i,
  /\btell\s+me\s+about\b/i,
  /\bwhat'?s\s+up\s+with\b/i,
  /\bupdate\s+on\b/i,
  /\bstatus\b/i,
  /\bdoing\b/i,
  /\bfeeling\b/i,
  /\bcheck\s+on\b/i,
  /\bis\s+\w+\s+okay\b/i,
  /\bis\s+\w+\s+alright\b/i,
  /\bis\s+\w+\s+fine\b/i,
  /\bokay\?\b/i,
  /\balright\?\b/i,
];

const SUBJECT_KEYWORDS = [
  /\bdad\b/i,
  /\bfather\b/i,
  /\bferdinand\b/i,
  /\bhim\b/i,
  /\bhe\b/i,
  /\bmy\s+dad\b/i,
  /\bmy\s+father\b/i,
  /\bthe\s+patient\b/i,
  /\bloved\s+one\b/i,
  /\bparent\b/i,
  /\bgrandpa\b/i,
  /\bgrandfather\b/i,
];

/**
 * Normalize question for WellNuo API (same logic as chat.tsx)
 */
function normalizeQuestion(userMessage: string): string {
  const msgLower = userMessage.toLowerCase().trim();

  const isStatusQuery = STATUS_KEYWORDS.some((pattern) => pattern.test(msgLower));
  const isAboutRecipient = SUBJECT_KEYWORDS.some((pattern) => pattern.test(msgLower));

  if (isStatusQuery && isAboutRecipient) {
    console.log(`[VoiceContext] Normalized '${userMessage}' -> 'how is dad doing'`);
    return 'how is dad doing';
  }

  if (isStatusQuery && !isAboutRecipient) {
    console.log(
      `[VoiceContext] Normalized '${userMessage}' -> 'how is dad doing' (assumed recipient)`
    );
    return 'how is dad doing';
  }

  console.log(`[VoiceContext] No normalization applied to: '${userMessage}'`);
  return userMessage;
}

export type VoiceStatus = 'idle' | 'listening' | 'processing' | 'speaking';

interface VoiceContextValue {
  // Current status of the voice session
  status: VoiceStatus;
  // Whether voice session is active (not idle)
  isActive: boolean;
  // Whether STT is currently listening
  isListening: boolean;
  // Whether TTS is currently speaking
  isSpeaking: boolean;
  // Whether processing API request
  isProcessing: boolean;
  // Current/last transcript from STT
  transcript: string;
  // Partial transcript (real-time preview)
  partialTranscript: string;
  // Last API response
  lastResponse: string | null;
  // Error message if any
  error: string | null;

  // Start voice session (begin listening)
  startSession: () => void;
  // Stop voice session
  stopSession: () => void;

  // Send transcript to API and get response with TTS
  // Called automatically when STT detects speech end, or manually
  sendTranscript: (text: string) => Promise<string | null>;

  // Update transcript from external STT hook
  setTranscript: (text: string) => void;
  setPartialTranscript: (text: string) => void;

  // Set status from external STT/TTS hooks
  setStatus: (status: VoiceStatus) => void;
  setIsListening: (listening: boolean) => void;
  setIsSpeaking: (speaking: boolean) => void;

  // Speak text using TTS
  speak: (text: string) => Promise<void>;
  // Stop TTS
  stopSpeaking: () => void;
  // Interrupt TTS if speaking (call when user starts talking)
  interruptIfSpeaking: () => boolean;

  // Voice API configuration
  voiceApiType: 'voice_ask' | 'ask_wellnuo_ai';
  updateVoiceApiType: (type: 'voice_ask' | 'ask_wellnuo_ai') => void;
}

const VoiceContext = createContext<VoiceContextValue | undefined>(undefined);

export function VoiceProvider({ children }: { children: ReactNode }) {
  const [status, setStatus] = useState<VoiceStatus>('idle');
  const [transcript, setTranscript] = useState('');
  const [partialTranscript, setPartialTranscript] = useState('');
  const [lastResponse, setLastResponse] = useState<string | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [isListening, setIsListening] = useState(false);
  const [isSpeaking, setIsSpeaking] = useState(false);

  // Voice transcript context for chat display
  const { addTranscriptEntry } = useVoiceTranscript();

  // API token cache
  const apiTokenRef = useRef<string | null>(null);

  // Abort controller for cancelling in-flight API requests
  const abortControllerRef = useRef<AbortController | null>(null);

  // Flag to prevent speak() after session stopped
  const sessionStoppedRef = useRef(false);

  // Deployment ID from settings
  const deploymentIdRef = useRef<string | null>(null);

  // Voice API type (voice_ask or ask_wellnuo_ai)
  const [voiceApiType, setVoiceApiType] = useState<'voice_ask' | 'ask_wellnuo_ai'>('ask_wellnuo_ai');

  // Load voice API type on mount
  React.useEffect(() => {
    const loadVoiceApiType = async () => {
      const savedType = await api.getVoiceApiType();
      setVoiceApiType(savedType);
      console.log('[VoiceContext] Loaded voice API type:', savedType);
    };
    loadVoiceApiType();
  }, []);

  // Load deployment ID on mount
  React.useEffect(() => {
    const loadDeploymentId = async () => {
      const savedId = await api.getDeploymentId();
      deploymentIdRef.current = savedId;
      console.log('[VoiceContext] Loaded deployment ID:', savedId);
    };
    loadDeploymentId();
  }, []);

  /**
   * Update voice API type (voice_ask or ask_wellnuo_ai)
   */
  const updateVoiceApiType = useCallback(async (type: 'voice_ask' | 'ask_wellnuo_ai') => {
    console.log('[VoiceContext] Updating voice API type to:', type);
    setVoiceApiType(type);
    await api.setVoiceApiType(type);
  }, []);

  /**
   * Get WellNuo API token (same as chat.tsx)
   */
  const getWellNuoToken = useCallback(async (): Promise<string> => {
    if (apiTokenRef.current) {
      return apiTokenRef.current;
    }

    const nonce = Math.floor(Math.random() * 1000000).toString();
    const response = await fetch(API_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
      body: new URLSearchParams({
        function: 'credentials',
        clientId: 'MA_001',
        user_name: WELLNUO_USER,
        ps: WELLNUO_PASSWORD,
        nonce: nonce,
      }).toString(),
    });

    const data = await response.json();
    if (data.status === '200 OK' && data.access_token) {
      apiTokenRef.current = data.access_token;
      console.log('[VoiceContext] WellNuo token obtained');
      return data.access_token;
    }
    throw new Error('Failed to authenticate with WellNuo API');
  }, []);

  /**
   * Send transcript to WellNuo API and speak the response
   */
  const sendTranscript = useCallback(
    async (text: string): Promise<string | null> => {
      const trimmedText = text.trim();
      if (!trimmedText) {
        console.log('[VoiceContext] Empty transcript, skipping API call');
        return null;
      }

      // Don't send if session was stopped
      if (sessionStoppedRef.current) {
        console.log('[VoiceContext] Session stopped, skipping API call');
        return null;
      }

      console.log(`[VoiceContext] Sending transcript to API (${voiceApiType}):`, trimmedText);
      setStatus('processing');
      setError(null);

      // Add user message to transcript for chat display
      addTranscriptEntry('user', trimmedText);

      // Create abort controller for this request
      if (abortControllerRef.current) {
        abortControllerRef.current.abort();
      }
      const abortController = new AbortController();
      abortControllerRef.current = abortController;

      try {
        // Get API token
        const token = await getWellNuoToken();

        // Check if aborted
        if (abortController.signal.aborted || sessionStoppedRef.current) {
          console.log('[VoiceContext] Request aborted before API call');
          return null;
        }

        // Normalize question
        const normalizedQuestion = normalizeQuestion(trimmedText);

        // Get deployment ID
        const deploymentId = deploymentIdRef.current || '21';

        // Log which API type we're using
        console.log('[VoiceContext] Using API type:', voiceApiType);

        // Build request params
        const requestParams: Record<string, string> = {
          function: voiceApiType, // Use the selected voiceApiType
          clientId: 'MA_001',
          user_name: WELLNUO_USER,
          token: token,
          question: normalizedQuestion,
          deployment_id: deploymentId,
        };

        // Only add beneficiary_names_dict if NOT in single deployment mode
        if (!SINGLE_DEPLOYMENT_MODE) {
          // For full app, would include beneficiary names dict
          // Currently single deployment mode only
        }

        const response = await fetch(API_URL, {
          method: 'POST',
          headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
          body: new URLSearchParams(requestParams).toString(),
          signal: abortController.signal,
        });

        const data = await response.json();

        // Check if session was stopped while waiting for response
        if (sessionStoppedRef.current) {
          console.log('[VoiceContext] Session stopped during API call, discarding response');
          return null;
        }

        if (data.ok && data.response?.body) {
          const responseText = data.response.body;
          console.log('[VoiceContext] API response:', responseText.slice(0, 100) + '...');
          setLastResponse(responseText);

          // Add Julia's response to transcript for chat display
          addTranscriptEntry('assistant', responseText);

          // Speak the response (will be skipped if session stopped)
          await speak(responseText);

          return responseText;
        } else {
          // Token might be expired
          if (data.status === '401 Unauthorized') {
            apiTokenRef.current = null;
            throw new Error('Session expired, please try again');
          }
          throw new Error(data.message || 'Could not get response');
        }
      } catch (err) {
        // Ignore abort errors
        if (err instanceof Error && err.name === 'AbortError') {
          console.log('[VoiceContext] API request aborted');
          return null;
        }

        // Handle API errors gracefully with voice feedback
        const errorMsg = err instanceof Error ? err.message : 'Unknown error';
        console.warn('[VoiceContext] API error:', errorMsg);

        // Create user-friendly error message for TTS
        const spokenError = `Sorry, I encountered an error: ${errorMsg}. Please try again.`;

        // Add error to transcript for chat display
        addTranscriptEntry('assistant', spokenError);

        // Speak the error message
        await speak(spokenError);

        // Don't set status to idle - return to listening after speaking error
        // This keeps the voice session active

        setError(errorMsg);
        return null;
      }
    },
    [getWellNuoToken, addTranscriptEntry, voiceApiType]
  );

  /**
   * Interrupt TTS when user starts speaking
   * Call this from the STT hook when voice activity is detected
   */
  const interruptIfSpeaking = useCallback(() => {
    if (isSpeaking) {
      console.log('[VoiceContext] User interrupted - stopping TTS');
      Speech.stop();
      setIsSpeaking(false);
      setStatus('listening');
      return true;
    }
    return false;
  }, [isSpeaking]);

  /**
   * Speak text using TTS
   */
  const speak = useCallback(async (text: string): Promise<void> => {
    if (!text.trim()) return;

    // Don't speak if session was stopped
    if (sessionStoppedRef.current) {
      console.log('[VoiceContext] Session stopped, skipping TTS');
      return;
    }

    console.log('[VoiceContext] Speaking:', text.slice(0, 50) + '...');
    setStatus('speaking');
    setIsSpeaking(true);

    return new Promise((resolve) => {
      Speech.speak(text, {
        language: 'en-US',
        rate: 0.9,
        pitch: 1.0,
        onStart: () => {
          console.log('[VoiceContext] TTS started');
        },
        onDone: () => {
          console.log('[VoiceContext] TTS completed');
          // Delay turning off green indicator to match STT restart delay (300ms)
          // This keeps the visual indicator on during the transition period
          setTimeout(() => {
            setIsSpeaking(false);
          }, 300);
          // Return to listening state after speaking (if session wasn't stopped)
          if (!sessionStoppedRef.current) {
            setStatus('listening');
          }
          resolve();
        },
        onError: (error) => {
          console.warn('[VoiceContext] TTS error:', error);
          // On error, turn off indicator immediately (no delay)
          setIsSpeaking(false);
          if (!sessionStoppedRef.current) {
            setStatus('listening');
          }
          resolve();
        },
        onStopped: () => {
          console.log('[VoiceContext] TTS stopped (interrupted)');
          // When interrupted by user, turn off indicator immediately
          setIsSpeaking(false);
          // Don't set status to listening if session was stopped by user
          if (!sessionStoppedRef.current) {
            setStatus('listening');
          }
          resolve();
        },
      });
    });
  }, []);

  /**
   * Stop TTS playback
   */
  const stopSpeaking = useCallback(() => {
    Speech.stop();
    setIsSpeaking(false);
  }, []);

  /**
   * Start voice session
   */
  const startSession = useCallback(() => {
    console.log('[VoiceContext] Starting voice session');
    sessionStoppedRef.current = false;
    setStatus('listening');
    setIsListening(true);
    setError(null);
    setTranscript('');
    setPartialTranscript('');
  }, []);

  /**
   * Stop voice session
   */
  const stopSession = useCallback(() => {
    console.log('[VoiceContext] Stopping voice session');
    // Mark session as stopped FIRST to prevent any pending callbacks
    sessionStoppedRef.current = true;
    // Abort any in-flight API requests
    if (abortControllerRef.current) {
      abortControllerRef.current.abort();
      abortControllerRef.current = null;
    }
    // Stop TTS
    Speech.stop();
    // Reset all state
    setStatus('idle');
    setIsListening(false);
    setIsSpeaking(false);
    setError(null);
  }, []);

  // Computed values
  const isActive = status !== 'idle';
  const isProcessing = status === 'processing';

  return (
    <VoiceContext.Provider
      value={{
        status,
        isActive,
        isListening,
        isSpeaking,
        isProcessing,
        transcript,
        partialTranscript,
        lastResponse,
        error,
        startSession,
        stopSession,
        sendTranscript,
        setTranscript,
        setPartialTranscript,
        setStatus,
        setIsListening,
        setIsSpeaking,
        speak,
        stopSpeaking,
        interruptIfSpeaking,
        voiceApiType,
        updateVoiceApiType,
      }}
    >
      {children}
    </VoiceContext.Provider>
  );
}

export function useVoice() {
  const context = useContext(VoiceContext);
  if (!context) {
    throw new Error('useVoice must be used within VoiceProvider');
  }
  return context;
}