import React, { useEffect, useState } from 'react';
import {
  View,
  Text,
  FlatList,
  TouchableOpacity,
  ActivityIndicator,
  Alert,
  KeyboardAvoidingView,
  Platform,
  Linking,
} from 'react-native';
import { useDispatch, useSelector } from 'react-redux';
import type { RootState, AppDispatch } from '../../store';
import {
  searchHuggingFaceModels,
  saveHuggingFaceApiKey,
  loadHuggingFaceApiKey,
  setSearchQuery,
  clearHFError,
} from '../../store/modelsSlice';
import HFModelItem from './HFModelItem';
import ApiKeyEditor from './ApiKeyEditor';
import SearchSection from './SearchSection';
import { handleModelDownload } from './downloadHelper';
import { createStyles } from './styles';
import { useTheme } from '../../theme/ThemeProvider';

export default function HuggingFaceModelsScreen() {
  const { colors } = useTheme();
  const styles = createStyles(colors);
  const dispatch = useDispatch<AppDispatch>();
  const {
    huggingFaceModels,
    huggingFaceApiKey,
    searchQuery,
    isLoadingHF,
    hfError,
    modelsDirectory,
    downloadProgress,
  } = useSelector((state: RootState) => state.models);

  const [showApiKeyInput, setShowApiKeyInput] = useState(false);
  const [tempApiKey, setTempApiKey] = useState('');
  const [localSearchQuery, setLocalSearchQuery] = useState(searchQuery);

  useEffect(() => {
    // Load saved API key on mount
    dispatch(loadHuggingFaceApiKey());
  }, [dispatch]);

  useEffect(() => {
    setTempApiKey(huggingFaceApiKey);
  }, [huggingFaceApiKey]);

  useEffect(() => {
    if (hfError) {
      Alert.alert('Erreur', hfError, [
        { text: 'OK', onPress: () => dispatch(clearHFError()) },
      ]);
    }
  }, [hfError, dispatch]);

  const handleSearch = () => {
    if (localSearchQuery.trim()) {
      dispatch(setSearchQuery(localSearchQuery.trim()));
      dispatch(searchHuggingFaceModels({
        query: localSearchQuery.trim(),
        apiKey: huggingFaceApiKey || undefined,
      }));
    }
  };

  const handleSaveApiKey = () => {
    dispatch(saveHuggingFaceApiKey(tempApiKey.trim()));
    setShowApiKeyInput(false);
    Alert.alert('Succès', 'Clé API enregistrée');
  };

  const handleOpenHuggingFace = () => {
    Linking.openURL('https://huggingface.co/settings/tokens');
  };

  const handleModelPress = (modelId: string) => {
    const url = `https://huggingface.co/${modelId}`;
    Linking.openURL(url);
  };

  const handleDownload = (modelId: string) => {
    handleModelDownload(modelId, modelsDirectory, dispatch);
  };

  const renderModelItem = ({ item }: { item: typeof huggingFaceModels[0] }) => {
    const modelProgress = downloadProgress[item.id];
    const isDownloading = !!modelProgress;
    const progressPercent = modelProgress 
      ? (modelProgress.bytesWritten / modelProgress.contentLength) * 100 
      : 0;

    return (
      <HFModelItem 
        model={item} 
        onPress={handleModelPress}
        onDownload={handleDownload}
        isDownloading={isDownloading}
        downloadProgress={progressPercent}
        bytesWritten={modelProgress?.bytesWritten || 0}
        contentLength={modelProgress?.contentLength || 0}
      />
    );
  };

  const renderEmptyList = () => {
    if (isLoadingHF) {
      return null;
    }
    
    return (
      <View style={styles.emptyContainer}>
        {searchQuery ? (
          <>
            <Text style={styles.emptyText}>Aucun modèle trouvé</Text>
            <Text style={styles.emptySubtext}>
              Essayez une autre recherche
            </Text>
          </>
        ) : (
          <>
            <Text style={styles.emptyText}>
              Recherchez des modèles GGUF
            </Text>
            <Text style={styles.emptySubtext}>
              Entrez un terme de recherche ci-dessus
            </Text>
          </>
        )}
      </View>
    );
  };

  return (
    <KeyboardAvoidingView
      style={styles.container}
      behavior={Platform.OS === 'ios' ? 'padding' : undefined}
    >
      {/* API Key Section */}
      <View style={styles.apiKeySection}>
        <View style={styles.apiKeyHeader}>
          <Text style={styles.sectionTitle}>Clé API HuggingFace</Text>
          <TouchableOpacity
            style={styles.infoButton}
            onPress={handleOpenHuggingFace}
          >
            <Text style={styles.infoButtonText}>ℹ️ Obtenir</Text>
          </TouchableOpacity>
        </View>
        
        {showApiKeyInput ? (
          <ApiKeyEditor
            tempApiKey={tempApiKey}
            onChangeText={setTempApiKey}
            onCancel={() => {
              setTempApiKey(huggingFaceApiKey);
              setShowApiKeyInput(false);
            }}
            onSave={handleSaveApiKey}
          />
        ) : (
          <View style={styles.apiKeyDisplay}>
            <Text style={styles.apiKeyText}>
              {huggingFaceApiKey ? '•••••••••••••' : 'Non configurée'}
            </Text>
            <TouchableOpacity
              style={styles.changeButton}
              onPress={() => setShowApiKeyInput(true)}
            >
              <Text style={styles.changeButtonText}>
                {huggingFaceApiKey ? 'Modifier' : 'Configurer'}
              </Text>
            </TouchableOpacity>
          </View>
        )}
        
        <Text style={styles.apiKeyHint}>
          Optionnel - Permet d'augmenter les limites de recherche
        </Text>
      </View>

      {/* Search Section */}
      <SearchSection
        searchQuery={localSearchQuery}
        onChangeText={setLocalSearchQuery}
        onSearch={handleSearch}
        isLoading={isLoadingHF}
      />

      {/* Results Section */}
      <View style={styles.resultsSection}>
        <Text style={styles.sectionTitle}>
          Résultats ({huggingFaceModels.length})
        </Text>
        
        {isLoadingHF && huggingFaceModels.length === 0 ? (
          <View style={styles.loadingContainer}>
            <ActivityIndicator size="large" color="#007AFF" />
            <Text style={styles.loadingText}>Recherche en cours...</Text>
          </View>
        ) : (
          <FlatList
            data={huggingFaceModels}
            renderItem={renderModelItem}
            keyExtractor={(item) => item.id}
            ListEmptyComponent={renderEmptyList}
            contentContainerStyle={styles.listContent}
          />
        )}
      </View>
    </KeyboardAvoidingView>
  );
}