/**
 * FileUpload - Datei-Auswahl und -Versand
 *
 * Oeffnet den Dateimanager des Geraets, zeigt eine Vorschau
 * und konvertiert die Datei zu Base64 fuer die Uebertragung.
 */

import React, { useState } from 'react';
import {
  View,
  Text,
  TouchableOpacity,
  Image,
  StyleSheet,
  ActivityIndicator,
} from 'react-native';
import DocumentPicker, {
  DocumentPickerResponse,
} from 'react-native-document-picker';
import RNFS from 'react-native-fs';

// --- Typen ---

export interface FileData {
  name: string;
  type: string;
  size: number;
  base64: string;
  uri: string;
}

interface FileUploadProps {
  onFileSelected: (file: FileData) => void;
  onCancel: () => void;
}

// Unterstuetzte Dateitypen
const SUPPORTED_TYPES = [
  DocumentPicker.types.images,
  DocumentPicker.types.pdf,
  DocumentPicker.types.docx,
  DocumentPicker.types.plainText,
];

// --- Komponente ---

const FileUpload: React.FC<FileUploadProps> = ({ onFileSelected, onCancel }) => {
  const [selectedFile, setSelectedFile] = useState<DocumentPickerResponse | null>(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const pickFile = async () => {
    setError(null);
    try {
      const result = await DocumentPicker.pick({
        type: SUPPORTED_TYPES,
        copyTo: 'cachesDirectory',
      });

      if (result.length > 0) {
        setSelectedFile(result[0]);
      }
    } catch (err) {
      if (DocumentPicker.isCancel(err)) {
        onCancel();
      } else {
        setError('Fehler beim Auswaehlen der Datei');
        console.error('[FileUpload] Fehler:', err);
      }
    }
  };

  const sendFile = async () => {
    if (!selectedFile) return;

    setLoading(true);
    try {
      // Datei lesen und zu Base64 konvertieren
      const filePath = selectedFile.fileCopyUri || selectedFile.uri;
      // URI-Schema entfernen fuer RNFS (file:// → absoluter Pfad)
      const cleanPath = filePath.replace('file://', '');
      const base64 = await RNFS.readFile(cleanPath, 'base64');

      const fileData: FileData = {
        name: selectedFile.name || 'unbenannt',
        type: selectedFile.type || 'application/octet-stream',
        size: selectedFile.size || 0,
        base64,
        uri: selectedFile.uri,
      };

      onFileSelected(fileData);
    } catch (err) {
      setError('Fehler beim Verarbeiten der Datei');
      console.error('[FileUpload] Verarbeitungsfehler:', err);
    } finally {
      setLoading(false);
    }
  };

  const isImage = selectedFile?.type?.startsWith('image/');
  const fileSizeFormatted = selectedFile?.size
    ? selectedFile.size > 1024 * 1024
      ? `${(selectedFile.size / (1024 * 1024)).toFixed(1)} MB`
      : `${(selectedFile.size / 1024).toFixed(0)} KB`
    : '';

  return (
    <View style={styles.container}>
      {!selectedFile ? (
        // Datei auswaehlen
        <TouchableOpacity style={styles.pickButton} onPress={pickFile} activeOpacity={0.7}>
          <Text style={styles.pickIcon}>{'\uD83D\uDCC1'}</Text>
          <Text style={styles.pickText}>Datei ausw\u00E4hlen</Text>
          <Text style={styles.pickHint}>JPG, PNG, PDF, DOCX, TXT</Text>
        </TouchableOpacity>
      ) : (
        // Vorschau und Senden
        <View style={styles.previewContainer}>
          {isImage ? (
            <Image source={{ uri: selectedFile.uri }} style={styles.imagePreview} />
          ) : (
            <View style={styles.filePreview}>
              <Text style={styles.fileIcon}>{'\uD83D\uDCC4'}</Text>
            </View>
          )}

          <Text style={styles.fileName} numberOfLines={1}>
            {selectedFile.name}
          </Text>
          <Text style={styles.fileSize}>{fileSizeFormatted}</Text>

          {error && <Text style={styles.errorText}>{error}</Text>}

          <View style={styles.buttonRow}>
            <TouchableOpacity
              style={styles.cancelButton}
              onPress={() => setSelectedFile(null)}
            >
              <Text style={styles.cancelButtonText}>Andere Datei</Text>
            </TouchableOpacity>

            <TouchableOpacity
              style={styles.sendButton}
              onPress={sendFile}
              disabled={loading}
            >
              {loading ? (
                <ActivityIndicator color="#FFFFFF" size="small" />
              ) : (
                <Text style={styles.sendButtonText}>Senden</Text>
              )}
            </TouchableOpacity>
          </View>
        </View>
      )}
    </View>
  );
};

// --- Styles ---

const styles = StyleSheet.create({
  container: {
    backgroundColor: '#1A1A2E',
    borderRadius: 16,
    padding: 20,
    margin: 12,
  },
  pickButton: {
    alignItems: 'center',
    padding: 30,
    borderWidth: 2,
    borderColor: '#2A2A3E',
    borderStyle: 'dashed',
    borderRadius: 12,
  },
  pickIcon: {
    fontSize: 40,
    marginBottom: 10,
  },
  pickText: {
    color: '#FFFFFF',
    fontSize: 16,
    fontWeight: '600',
  },
  pickHint: {
    color: '#666680',
    fontSize: 12,
    marginTop: 4,
  },
  previewContainer: {
    alignItems: 'center',
  },
  imagePreview: {
    width: 200,
    height: 200,
    borderRadius: 12,
    marginBottom: 12,
    resizeMode: 'cover',
  },
  filePreview: {
    width: 80,
    height: 80,
    borderRadius: 12,
    backgroundColor: '#2A2A3E',
    alignItems: 'center',
    justifyContent: 'center',
    marginBottom: 12,
  },
  fileIcon: {
    fontSize: 36,
  },
  fileName: {
    color: '#FFFFFF',
    fontSize: 14,
    fontWeight: '500',
    maxWidth: 250,
  },
  fileSize: {
    color: '#666680',
    fontSize: 12,
    marginTop: 2,
  },
  errorText: {
    color: '#FF3B30',
    fontSize: 12,
    marginTop: 8,
  },
  buttonRow: {
    flexDirection: 'row',
    marginTop: 16,
    gap: 12,
  },
  cancelButton: {
    paddingHorizontal: 20,
    paddingVertical: 10,
    borderRadius: 8,
    backgroundColor: '#2A2A3E',
  },
  cancelButtonText: {
    color: '#8888AA',
    fontSize: 14,
    fontWeight: '600',
  },
  sendButton: {
    paddingHorizontal: 28,
    paddingVertical: 10,
    borderRadius: 8,
    backgroundColor: '#0096FF',
    minWidth: 90,
    alignItems: 'center',
  },
  sendButtonText: {
    color: '#FFFFFF',
    fontSize: 14,
    fontWeight: '700',
  },
});

export default FileUpload;