import { useState, useEffect, useCallback, useRef } from 'react';
import { Alert } from 'react-native';
import { useTranslation } from 'react-i18next';
import { getAuthenticatedClient } from '~/features/auth/lib/supabaseClient';
import { tokenManager } from '~/features/auth/services/tokenManager';
import { getTranscriptText, getUtterances } from '~/features/memos/utils/transcriptUtils';

// Debug utility
const debug = __DEV__ ? console.debug : () => {};

// Type definitions
interface MemoType {
  id: string;
  title?: string;
  intro?: string;
  created_at: string;
  transcript?: string; // Full transcription text (moved from source for performance)
  location?: string; // PostGIS POINT format
  source?: {
    type?: string;
    content?: string;
    transcript?: string;
    transcription?: string;
    speakers?: Record<string, Array<{text: string; offset?: number; duration?: number}>>;
    utterances?: Array<{text: string; offset?: number; duration?: number; speakerId?: string}>;
    duration?: number;
    duration_seconds?: number;
    audio_path?: string;
    additional_recordings?: Array<{
      path: string;
      type: string;
      timestamp: string;
      status: string;
      transcript?: string;
      speakers?: Record<string, Array<{text: string; offset?: number; duration?: number}>>;
      utterances?: Array<{text: string; offset?: number; duration?: number; speakerId?: string}>;
      languages?: string[];
    }>;
  };
  metadata?: {
    transcription?: boolean;
    blueprint_id?: string;
    speakerLabels?: Record<string, string>;
    transcript?: string;
    utterances?: Array<{text: string; offset?: number; duration?: number; speakerId?: string}>;
    location?: {
      latitude: number;
      longitude: number;
      timestamp: number;
    };
    stats?: {
      viewCount: number;
      wordCount?: number;
      lastViewed?: string;
      audioDuration?: number;
    };
  };
}

interface MemoryType {
  id: string;
  title: string;
  content: string;
  metadata?: Record<string, unknown>;
}

interface LoadingStates {
  memo: boolean;
  question: boolean;
  memories: boolean;
  audio: boolean;
  critical: boolean;
}

interface MemoState {
  // Core memo data
  memo: MemoType | null;
  memories: MemoryType[];
  localMemories: MemoryType[];
  
  // Memo properties
  isPinned: boolean;
  isEditMode: boolean;
  editTitle: string;
  editIntro: string;
  editTranscript: string;
  editUtterances: Array<{text: string; offset?: number; duration?: number; speakerId?: string}> | null;
  
  // Audio and media
  audioUrl: string | null;
  
  // Loading states
  loadingStates: LoadingStates;
  
  // Word replacement
  wordToReplace: string;
  replacementWord: string;
  speakerMappings: Record<string, string>;
  
  // Summary and processing
  summaryError: string | null;
  isGeneratingSummary: boolean;
}

interface MemoActions {
  // Loading state management
  updateLoadingState: (key: keyof LoadingStates, value: boolean) => void;
  isAnyLoading: boolean;
  
  // Memo operations
  loadMemoData: (memoId: string) => Promise<void>;
  handleEditStart: () => void;
  handleSaveEdit: (memoId: string) => Promise<void>;
  handleCancelEdit: () => void;
  handlePinToggle: (memoId: string) => Promise<void>;
  
  // Audio operations
  getSignedUrl: (filePath: string) => Promise<string | null>;
  
  // Memory operations
  setMemories: React.Dispatch<React.SetStateAction<MemoryType[]>>;
  setLocalMemories: React.Dispatch<React.SetStateAction<any[]>>;
  
  // Memo operations
  setMemo: React.Dispatch<React.SetStateAction<MemoType | null>>;
  
  // Edit operations
  setEditTitle: (title: string) => void;
  setEditIntro: (intro: string) => void;
  setEditTranscript: (transcript: string) => void;
  setEditUtterances: (utterances: Array<{text: string; offset?: number; duration?: number; speakerId?: string}> | null) => void;
  updateEditUtterance: (index: number, newText: string) => void;
  
  // Word replacement
  setWordToReplace: (word: string) => void;
  setReplacementWord: (word: string) => void;
  setSpeakerMappings: React.Dispatch<React.SetStateAction<Record<string, string>>>;
  
  // Summary operations
  setSummaryError: (error: string | null) => void;
  setIsGeneratingSummary: (generating: boolean) => void;
}

export function useMemoState(): MemoState & MemoActions {
  const { t } = useTranslation();
  
  // Core memo data
  const [memo, setMemo] = useState<MemoType | null>(null);
  const [memories, setMemories] = useState<MemoryType[]>([]);
  const [localMemories, setLocalMemories] = useState<any[]>([]);
  // Removed unused variable - memoryUpdateTimeouts
  // const memoryUpdateTimeouts = useRef<Map<string, ReturnType<typeof setTimeout>>>(new Map());
  
  // Memo properties
  const [isPinned, setIsPinned] = useState(false);
  const [isEditMode, setIsEditMode] = useState(false);
  const [editTitle, setEditTitle] = useState('');
  const [editIntro, setEditIntro] = useState('');
  const [editTranscript, setEditTranscript] = useState('');
  const [editUtterances, setEditUtterances] = useState<Array<{text: string; offset?: number; duration?: number; speakerId?: string}> | null>(null);
  
  // Refs to capture latest values to prevent race conditions
  const editTranscriptRef = useRef('');
  const editUtterancesRef = useRef<Array<{text: string; offset?: number; duration?: number; speakerId?: string}> | null>(null);
  
  // Audio and media
  const [audioUrl, setAudioUrl] = useState<string | null>(null);
  
  // Loading states
  const [loadingStates, setLoadingStates] = useState<LoadingStates>({
    memo: true,
    question: false,
    memories: false,
    audio: false,
    critical: false
  });
  
  // Word replacement
  const [wordToReplace, setWordToReplace] = useState('');
  const [replacementWord, setReplacementWord] = useState('');
  const [speakerMappings, setSpeakerMappings] = useState<Record<string, string>>({});
  
  // Summary and processing
  const [summaryError, setSummaryError] = useState<string | null>(null);
  const [isGeneratingSummary, setIsGeneratingSummary] = useState(false);
  
  // Loading state helper
  const updateLoadingState = useCallback((key: keyof LoadingStates, value: boolean) => {
    setLoadingStates(prev => ({ ...prev, [key]: value }));
  }, []);
  
  const isAnyLoading = Object.values(loadingStates).some(Boolean);
  
  // Sync localMemories with memories when not editing
  useEffect(() => {
    if (!isEditMode) {
      setLocalMemories(memories);
    }
  }, [memories, isEditMode]);
  
  // Cleanup refs on unmount
  useEffect(() => {
    return () => {
      // Clear refs holding potentially large data
      editTranscriptRef.current = '';
      editUtterancesRef.current = null;
    };
  }, []);
  
  // Generate signed URL for files
  const getSignedUrl = useCallback(async (filePath: string): Promise<string | null> => {
    try {
      // Use authenticated client to ensure proper RLS policy enforcement
      const supabase = await getAuthenticatedClient();
      
      const { data, error } = await supabase
        .storage
        .from('user-uploads')
        .createSignedUrl(filePath, 60 * 60); // 1 hour expiration
      
      if (error) {
        debug('Error generating signed URL:', error.message);
        return null;
      }
      
      return data.signedUrl;
    } catch (error) {
      debug('Error in getSignedUrl:', error);
      return null;
    }
  }, []);
  
  // Load memo data with retry logic
  const loadMemoData = useCallback(async (memoId: string, retryCount = 0) => {
    // Validate memoId before proceeding
    if (!memoId || memoId === 'undefined' || memoId === 'null' || memoId.length === 0) {
      console.error('MemoState: Invalid memo ID provided:', memoId);
      updateLoadingState('memo', false);
      Alert.alert(
        t('common.error', 'Fehler'),
        t('memo.invalid_id', 'Ungültige Memo-ID.')
      );
      return;
    }
    
    try {
      debug(`MemoState: Fetching memo with id: ${memoId}, retry attempt: ${retryCount}`);
      updateLoadingState('memo', true);
      
      // Wait for valid token before proceeding
      const token = await tokenManager.getValidToken({ maxRetries: 3 });
      
      if (!token) {
        debug('MemoState: Unable to obtain valid authentication token');
        throw new Error('Authentication failed - unable to obtain valid token');
      }
      
      debug('MemoState: Valid token obtained, proceeding with memo fetch');
      const supabase = await getAuthenticatedClient();
      
      // Increment view count
      await supabase.rpc('increment_memo_view_count', {
        memo_id: memoId
      });
      
      // Parallelize memo and memories loading
      const [memoResult, memoriesResult] = await Promise.all([
        // Load memo
        supabase
          .from('memos')
          .select('*')
          .eq('id', memoId)
          .single(),
        // Load memories in parallel
        supabase
          .from('memories')
          .select('id, title, content, metadata')
          .eq('memo_id', memoId)
          .order('sort_order', { ascending: true })
          .order('created_at', { ascending: false })
      ]);
      
      const { data, error } = memoResult;
        
      if (error) {
        console.error('MemoState: Error fetching memo:', error.message, error);
        // Log more details about the error
        if (error.code) {
          console.error('MemoState: Error code:', error.code);
        }
        if (error.details) {
          console.error('MemoState: Error details:', error.details);
        }
        if (error.hint) {
          console.error('MemoState: Error hint:', error.hint);
        }
        
        // Check if this might be an authentication issue
        const tokenState = tokenManager.getTokenState();
        const isAuthRelatedError = (
          (error.code === 'PGRST116' && error.details?.includes('0 rows') && tokenState !== 'valid') ||
          error.code === 'PGRST301' || // JWT expired
          error.message?.includes('JWT') ||
          error.message?.includes('token')
        );
        
        // Retry logic for temporary failures and auth issues
        const isRetryableError = (
          isAuthRelatedError ||
          error.code === '57014' || // Query canceled
          error.message?.includes('network') ||
          error.message?.includes('fetch')
        );
        
        if (retryCount < 2 && isRetryableError) {
          debug(`MemoState: Retryable error (auth: ${isAuthRelatedError}), retrying in ${1000 * (retryCount + 1)}ms...`, error.code);
          updateLoadingState('memo', false); // Reset loading state for retry
          setTimeout(() => {
            loadMemoData(memoId, retryCount + 1);
          }, 1000 * (retryCount + 1)); // Exponential backoff: 1s, 2s (longer for auth issues)
          return;
        }
        
        // Show user-friendly error message based on error type
        if (error.code === 'PGRST116' && error.details?.includes('0 rows') && !isAuthRelatedError) {
          // Only show "not found" if we're sure it's not an auth issue
          Alert.alert(
            t('common.error', 'Fehler'),
            t('memo.not_found', 'Das Memo wurde nicht gefunden. Es wurde möglicherweise gelöscht.')
          );
          // Clear the memo from the store to prevent showing stale data
          setMemo(null);
        } else if (error.message?.includes('permission') || error.code === '42501') {
          Alert.alert(
            t('common.error', 'Fehler'),
            t('memo.no_permission', 'Sie haben keine Berechtigung, dieses Memo anzuzeigen.')
          );
        } else {
          console.log("ERROR LOADING MEMO", error);
          Alert.alert(
            t('common.error', 'Fehler'),
            t('memo.could_not_load', 'Memo konnte nicht geladen werden.')
          );
        }
        return;
      }
      
      if (!data) {
        console.error('MemoState: No data returned for memo ID:', memoId);
        Alert.alert(
          t('common.error', 'Fehler'),
          t('memo.not_found', 'Das Memo wurde nicht gefunden.')
        );
        return;
      }
      
      console.log('[useMemoState] Fetched memo data:', data);
      console.log('[useMemoState] Location field in memo:', data.location);
      setMemo(data);
      setIsPinned(data.is_pinned || false);
      
      // Generate audio URL if audio_path exists
      debug('MemoState: Checking audio data - source.audio_path:', data?.source?.audio_path);
      if (data?.source?.audio_path) {
        updateLoadingState('audio', true);
        const audioPath = data.source.audio_path;
        debug('MemoState: Audio path found:', audioPath);
        if (audioPath) {
          debug('MemoState: Requesting signed URL for audio path:', audioPath);
          const signedUrl = await getSignedUrl(audioPath);
          if (signedUrl) {
            setAudioUrl(signedUrl);
            debug('MemoState: Audio URL generated successfully:', signedUrl.substring(0, 100) + '...');
          } else {
            debug('MemoState: Failed to generate audio URL for path:', audioPath);
          }
        } else {
          debug('MemoState: Audio path is empty or null');
        }
        updateLoadingState('audio', false);
      } else {
        debug('MemoState: No audio path found in memo source data');
        setAudioUrl(null);
      }
      
      // Handle memories result from parallel loading
      const { data: memoriesData, error: memoriesError } = memoriesResult;
      
      if (memoriesError) {
        debug('Error fetching memories:', memoriesError.message);
      } else if (memoriesData) {
        debug('Fetched memories count:', memoriesData.length);
        setMemories(memoriesData);
      }
    } catch (error: any) {
      debug('MemoState: Error in loadMemoData:', error);
      
      // Handle authentication errors specifically
      if (error.message?.includes('Authentication failed')) {
        // Don't show alert for auth failures - just retry silently
        if (retryCount < 2) {
          debug('MemoState: Authentication error, retrying...');
          updateLoadingState('memo', false);
          setTimeout(() => {
            loadMemoData(memoId, retryCount + 1);
          }, 1000 * (retryCount + 1));
          return;
        }
      }
      
      // For other errors, show generic error message
      Alert.alert(
        t('common.error', 'Fehler'),
        t('memo.load_error', 'Das Memo konnte nicht geladen werden. Bitte versuchen Sie es später erneut.')
      );
    } finally {
      updateLoadingState('memo', false);
    }
  }, [getSignedUrl, updateLoadingState, t]);
  
  // Edit operations
  const handleEditStart = useCallback(() => {
    debug('handleEditStart called:', { isEditMode, hasMemo: !!memo });
    if (!isEditMode && memo) {
      const initialTitle = memo.title || '';
      const initialIntro = memo.intro || '';
      const initialTranscript = getTranscriptText(memo);
      
      // Handle utterances from different possible locations
      const initialUtterances = getUtterances(memo);
      
      debug('handleEditStart - Setting initial values:', {
        initialTitle,
        initialIntro,
        initialTranscript,
        initialUtterances
      });
      
      setEditTitle(initialTitle);
      setEditIntro(initialIntro);
      setEditTranscript(initialTranscript);
      setEditUtterances(initialUtterances);
      
      // Also update refs
      editTranscriptRef.current = initialTranscript;
      editUtterancesRef.current = initialUtterances;
      
      setIsEditMode(true);
      debug('Edit mode activated');
    } else {
      debug('handleEditStart - Skipped, already in edit mode or no memo');
    }
  }, [isEditMode, memo]);
  
  // Debug memo changes during edit mode
  useEffect(() => {
    if (isEditMode) {
      debug('Memo changed during edit mode:', {
        memoId: memo?.id,
        memoTitle: memo?.title,
        memoTranscript: memo?.transcript || memo?.source?.transcript || memo?.metadata?.transcript,
        currentEditTranscript: editTranscript,
        currentEditUtterances: editUtterances?.length
      });
    }
  }, [memo, isEditMode, editTranscript, editUtterances]);
  
  const handleSaveEdit = useCallback(async (memoId: string) => {
    if (!memo || !memoId) return;

    try {
      updateLoadingState('memo', true);
      const supabase = await getAuthenticatedClient();
      
      // Capture current edit values to prevent race conditions (use refs for reliable values)
      const currentEditTitle = editTitle;
      const currentEditIntro = editIntro;
      const currentEditTranscript = editTranscriptRef.current;
      const currentEditUtterances = editUtterancesRef.current;
      
      debug('handleSaveEdit - Captured current values:', {
        currentEditTitle,
        currentEditIntro,
        currentEditTranscript,
        currentEditUtterances,
        stateTranscript: editTranscript,
        refTranscript: editTranscriptRef.current
      });
      
      // Prepare update data
      const updateData: Record<string, unknown> = {
        title: currentEditTitle,
        intro: currentEditIntro,
      };
      
      // Update transcript and utterances if they changed  
      const originalTranscript = getTranscriptText(memo);
      const originalUtterances = getUtterances(memo);
      
      debug('handleSaveEdit - Checking for changes:', {
        currentEditTranscript,
        originalTranscript,
        currentEditUtterances,
        originalUtterances,
        transcriptChanged: currentEditTranscript !== originalTranscript,
        utterancesChanged: JSON.stringify(currentEditUtterances) !== JSON.stringify(originalUtterances)
      });
      
      if (currentEditTranscript !== originalTranscript || JSON.stringify(currentEditUtterances) !== JSON.stringify(originalUtterances)) {
        // Determine the utterances to save
        let utterancesToSave = currentEditUtterances;
        
        // When transcript changes but we have no utterances or just one, create/update the single utterance
        if (currentEditTranscript !== originalTranscript && (!currentEditUtterances || currentEditUtterances.length <= 1)) {
          // If transcript changed and we have no utterances or just one, create a single utterance
          utterancesToSave = [{
            text: currentEditTranscript,
            speakerId: currentEditUtterances?.[0]?.speakerId || 'default',
            offset: currentEditUtterances?.[0]?.offset || 0,
            duration: currentEditUtterances?.[0]?.duration || 0
          }];
        }
        
        // Update source with utterances only (no transcript field)
        if (memo.source && utterancesToSave) {
          const updatedSource = {
            ...memo.source,
            utterances: utterancesToSave
          };
          
          // Remove any legacy transcript fields
          delete updatedSource.transcript;
          delete updatedSource.content;
          delete updatedSource.transcription;
          
          updateData.source = updatedSource;
        }
        
        // Also remove transcript from top level if it exists
        updateData.transcript = null;
      }
      
      const { data, error } = await supabase
        .from('memos')
        .update(updateData)
        .eq('id', memoId)
        .select('id, title, intro, created_at, source, metadata, is_pinned')
        .single();
        
      if (error) {
        debug('Error updating memo:', error.message);
        Alert.alert(
          t('common.error', 'Fehler'),
          t('memo.update_error', 'Das Memo konnte nicht aktualisiert werden.')
        );
        return;
      }
      
      debug('Memo updated successfully:', data);
      debug('New memo utterances:', data.source?.utterances);
      debug('New memo transcript:', data.source?.transcript || data.metadata?.transcript);
      debug('New memo speakerMap:', (data.source as any)?.speakerMap);
      debug('Full new memo source:', data.source);
      debug('Full new memo metadata:', data.metadata);
      setMemo(data);
      
      // Clear edit states when leaving edit mode
      setEditTranscript('');
      setEditUtterances(null);
      editTranscriptRef.current = '';
      editUtterancesRef.current = null;
      
      setIsEditMode(false);
    } catch (error) {
      debug('Error in handleSaveEdit:', error);
      Alert.alert(
        t('common.error', 'Fehler'),
        t('common.unexpected_error', 'Ein unerwarteter Fehler ist aufgetreten.')
      );
    } finally {
      updateLoadingState('memo', false);
    }
  }, [memo, editTitle, editIntro, updateLoadingState, t]);
  
  const handleCancelEdit = useCallback(() => {
    setIsEditMode(false);
    debug('Edit mode canceled');
  }, []);
  
  // Pin toggle operation
  const handlePinToggle = useCallback(async (memoId: string) => {
    if (!memoId) return;
    
    const newPinnedState = !isPinned;
    
    try {
      updateLoadingState('memo', true);
      const supabase = await getAuthenticatedClient();
      
      const { error } = await supabase
        .from('memos')
        .update({ is_pinned: newPinnedState })
        .eq('id', memoId);
        
      if (error) {
        debug('Error updating pin status:', error.message);
        Alert.alert(
          t('common.error', 'Fehler'),
          t('memo.pin_error', 'Der Pin-Status konnte nicht aktualisiert werden.')
        );
        return;
      }
      
      setIsPinned(newPinnedState);
      debug('Pin status updated successfully');
    } catch (error) {
      debug('Error in handlePinToggle:', error);
    } finally {
      updateLoadingState('memo', false);
    }
  }, [isPinned, updateLoadingState, t]);
  
  // Helper function to update individual utterance
  const updateEditUtterance = useCallback((index: number, newText: string) => {
    debug('updateEditUtterance called:', { index, newText, hasEditUtterances: !!editUtterances });
    if (!editUtterances) return;
    
    const updatedUtterances = [...editUtterances];
    if (updatedUtterances[index]) {
      updatedUtterances[index] = {
        ...updatedUtterances[index],
        text: newText,
      };
      debug('Setting updated utterances:', updatedUtterances);
      setEditUtterances(updatedUtterances);
      // Also update ref
      editUtterancesRef.current = updatedUtterances;
    }
  }, [editUtterances]);
  
  // Custom setEditTranscript that also updates ref
  const setEditTranscriptWithRef = useCallback((transcript: string) => {
    debug('setEditTranscriptWithRef called:', transcript);
    setEditTranscript(transcript);
    editTranscriptRef.current = transcript;
  }, []);
  
  return {
    // State
    memo,
    memories,
    localMemories,
    isPinned,
    isEditMode,
    editTitle,
    editIntro,
    editTranscript,
    editUtterances,
    audioUrl,
    loadingStates,
    wordToReplace,
    replacementWord,
    speakerMappings,
    summaryError,
    isGeneratingSummary,
    
    // Actions
    updateLoadingState,
    isAnyLoading,
    loadMemoData,
    handleEditStart,
    handleSaveEdit,
    handleCancelEdit,
    handlePinToggle,
    getSignedUrl,
    setMemories,
    setLocalMemories,
    setMemo,
    setEditTitle,
    setEditIntro,
    setEditTranscript: setEditTranscriptWithRef,
    setEditUtterances,
    updateEditUtterance,
    setWordToReplace,
    setReplacementWord,
    setSpeakerMappings,
    setSummaryError,
    setIsGeneratingSummary,
  };
}