environment_monitoring_app/lib/services/air_sampling_service.dart

// lib/services/air_sampling_service.dart

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as path;
import 'package:image/image.dart' as img;
import 'package:intl/intl.dart';

// Import your actual data models
import '../models/air_installation_data.dart';
import '../models/air_collection_data.dart';

// Import a local storage service (you would create this)
// import 'local_storage_service.dart';

// A placeholder for your actual API service
class AirApiService {
  Future<Map<String, dynamic>> submitInstallation({
    required Map<String, dynamic> installationJson,
    required List<File> imageFiles,
  }) async {
    // In a real app, you would build an http.MultipartRequest here
    // to send the JSON data and image files to your server.
    print("Submitting Installation to API...");
    print("Data: $installationJson");
    print("Image count: ${imageFiles.length}");

    // Simulate a network call
    await Future.delayed(const Duration(seconds: 1));

    // Simulate a successful response
    return {
      'status': 'S1', // 'S1' for Server Success (Installation Pending Collection)
      'message': 'Installation data successfully submitted to the server.',
      'refID': installationJson['refID'],
    };
  }

  Future<Map<String, dynamic>> submitCollection({
    required Map<String, dynamic> collectionJson,
    required List<File> imageFiles,
  }) async {
    // In a real app, this would update the existing record linked by 'installationRefID'
    print("Submitting Collection to API...");
    print("Data: $collectionJson");
    print("Image count: ${imageFiles.length}");

    // Simulate a network call
    await Future.delayed(const Duration(seconds: 1));

    // Simulate a successful response
    return {
      'status': 'S3', // 'S3' for Server Success (Completed)
      'message': 'Collection data successfully linked and submitted.',
    };
  }
}


/// A dedicated service to handle all business logic for the Air Manual Sampling feature.
class AirSamplingService {
  final AirApiService _apiService = AirApiService();
  // final LocalStorageService _localStorageService = LocalStorageService();

  /// Picks an image from the specified source, adds a timestamp watermark,
  /// and saves it to a temporary directory with a standardized name.
  Future<File?> pickAndProcessImage(
      ImageSource source, {
        required String stationCode,
        required String imageInfo, // e.g., "INSTALLATION_LEFT", "COLLECTION_CHART"
      }) async {
    final picker = ImagePicker();
    final XFile? photo = await picker.pickImage(
        source: source, imageQuality: 85, maxWidth: 1024);
    if (photo == null) return null;

    final bytes = await photo.readAsBytes();
    img.Image? originalImage = img.decodeImage(bytes);
    if (originalImage == null) return null;

    // Prepare watermark text
    final String watermarkTimestamp =
    DateFormat('yyyy-MM-dd HH:mm:ss').format(DateTime.now());
    final font = img.arial24;

    // Add a white background for better text visibility
    final textWidth = watermarkTimestamp.length * 12; // Estimate width
    img.fillRect(originalImage,
        x1: 5,
        y1: 5,
        x2: textWidth + 15,
        y2: 35,
        color: img.ColorRgb8(255, 255, 255));
    img.drawString(originalImage, watermarkTimestamp,
        font: font, x: 10, y: 10, color: img.ColorRgb8(0, 0, 0));

    // Create a standardized file name
    final tempDir = await getTemporaryDirectory();
    final fileTimestamp = watermarkTimestamp.replaceAll(':', '-').replaceAll(' ', '_');
    final newFileName =
        "${stationCode}_${fileTimestamp}_${imageInfo.replaceAll(' ', '')}.jpg";
    final filePath = path.join(tempDir.path, newFileName);

    // Save the processed image and return the file
    return File(filePath)..writeAsBytesSync(img.encodeJpg(originalImage));
  }

  /// Submits only the installation data.
  Future<Map<String, dynamic>> submitInstallation(AirInstallationData data) async {
    try {
      // Prepare image files for upload
      final List<File> images = [];
      if (data.image1 != null) images.add(data.image1!);
      if (data.image2 != null) images.add(data.image2!);
      if (data.image3 != null) images.add(data.image3!);
      if (data.image4 != null) images.add(data.image4!);

      // In a real app, you would check connectivity here before attempting the API call
      final result = await _apiService.submitInstallation(
        installationJson: data.toJson(),
        imageFiles: images,
      );
      return result;
    } catch (e) {
      print("API submission failed: $e. Saving installation locally.");
      // --- Fallback to Local Storage ---
      // TODO: Implement local DB save for installation data
      data.status = 'L1'; // Mark as saved locally, pending collection
      // await _localStorageService.saveAirInstallationData(data);
      return {
        'status': 'L1',
        'message': 'Installation data saved locally.',
      };
    }
  }

  /// Submits only the collection data, linked to a previous installation.
  Future<Map<String, dynamic>> submitCollection(AirCollectionData data) async {
    try {
      // Prepare image files for upload
      final List<File> images = [];
      if (data.imageSiteLeft != null) images.add(data.imageSiteLeft!);
      if (data.imageSiteRight != null) images.add(data.imageSiteRight!);
      // ... add all other collection images

      // In a real app, you would check connectivity here
      final result = await _apiService.submitCollection(
        collectionJson: data.toJson(),
        imageFiles: images,
      );
      return result;
    } catch (e) {
      print("API submission failed: $e. Saving collection locally.");
      // --- Fallback to Local Storage ---
      // TODO: Implement local DB save for collection data
      data.status = 'L3'; // Mark as completed locally
      // await _localStorageService.saveAirCollectionData(data);
      return {
        'status': 'L3',
        'message': 'Collection data saved locally.',
      };
    }
  }

  /// Fetches installations that are pending collection.
  Future<List<AirInstallationData>> getPendingInstallations() async {
    // In a real app, this would query your local database or a server endpoint
    // for records with status 'L1' (local, pending) or 'S1' (server, pending).
    print("Fetching pending installations...");
    await Future.delayed(const Duration(milliseconds: 500)); // Simulate network/DB delay

    // Return placeholder data for demonstration
    return [
      AirInstallationData(
        refID: 'ABC1234567',
        stationID: 'SGR01',
        locationName: 'Shah Alam',
        samplingDate: '2025-08-10',
        temp: '28.5',
        status: 'L1', // Example of a locally saved installation
      ),
      AirInstallationData(
        refID: 'DEF8901234',
        stationID: 'JHR02',
        locationName: 'Muar',
        samplingDate: '2025-08-09',
        temp: '29.1',
        status: 'S1', // Example of a server-saved installation
      ),
      AirInstallationData(
        refID: 'GHI5678901',
        stationID: 'PRK01',
        locationName: 'Ipoh',
        samplingDate: '2025-08-11',
        temp: '27.9',
        status: 'S1',
      ),
    ];
  }

  void dispose() {
    // Clean up any resources if necessary
  }
}