// lib/services/retry_service.dart

import 'dart:convert';
import 'dart:io';
import 'package:flutter/foundation.dart';
import 'package:path/path.dart' as p;

import 'package:environment_monitoring_app/models/in_situ_sampling_data.dart';
import 'package:environment_monitoring_app/services/marine_in_situ_sampling_service.dart';
import 'package:environment_monitoring_app/models/river_in_situ_sampling_data.dart';
import 'package:environment_monitoring_app/services/river_in_situ_sampling_service.dart';
// *** ADDED: Import River Investigative Model and Service ***
import 'package:environment_monitoring_app/models/river_inves_manual_sampling_data.dart';
import 'package:environment_monitoring_app/services/river_investigative_sampling_service.dart';
// *** END ADDED ***
import 'package:environment_monitoring_app/models/marine_inves_manual_sampling_data.dart';
import 'package:environment_monitoring_app/services/marine_investigative_sampling_service.dart';
import 'package:environment_monitoring_app/models/tarball_data.dart';
import 'package:environment_monitoring_app/services/marine_tarball_sampling_service.dart';
import 'package:environment_monitoring_app/services/api_service.dart';
import 'package:environment_monitoring_app/services/base_api_service.dart';
import 'package:environment_monitoring_app/services/ftp_service.dart';
import 'package:environment_monitoring_app/services/server_config_service.dart';
import 'package:environment_monitoring_app/auth_provider.dart';

/// A dedicated service to manage the queue of failed API, FTP, and complex submission tasks.
class RetryService {
  final DatabaseHelper _dbHelper = DatabaseHelper();
  final BaseApiService _baseApiService = BaseApiService();
  final FtpService _ftpService = FtpService();
  final ServerConfigService _serverConfigService = ServerConfigService();
  bool _isProcessing = false;

  MarineInSituSamplingService? _marineInSituService;
  RiverInSituSamplingService? _riverInSituService;
  MarineInvestigativeSamplingService? _marineInvestigativeService;
  MarineTarballSamplingService? _marineTarballService;
  // *** ADDED: River Investigative Service member ***
  RiverInvestigativeSamplingService? _riverInvestigativeService;
  // *** END ADDED ***
  AuthProvider? _authProvider;

  // *** MODIFIED: Added riverInvestigativeService to initialize ***
  void initialize({
    required MarineInSituSamplingService marineInSituService,
    required RiverInSituSamplingService riverInSituService,
    required MarineInvestigativeSamplingService marineInvestigativeService,
    required RiverInvestigativeSamplingService riverInvestigativeService, // <-- Added parameter
    required MarineTarballSamplingService marineTarballService,
    required AuthProvider authProvider,
  }) {
    _marineInSituService = marineInSituService;
    _riverInSituService = riverInSituService;
    _marineInvestigativeService = marineInvestigativeService;
    _riverInvestigativeService = riverInvestigativeService; // <-- Assign parameter
    _marineTarballService = marineTarballService;
    _authProvider = authProvider;
  }
  // *** END MODIFIED ***


  /// Adds a generic, complex task to the queue, to be handled by a background processor.
  Future<void> queueTask({
    required String type,
    required Map<String, dynamic> payload,
  }) async {
    await _dbHelper.queueFailedRequest({
      'type': type,
      'endpoint_or_path': 'N/A', // Not applicable for complex tasks initially
      'payload': jsonEncode(payload),
      'timestamp': DateTime.now().toIso8601String(),
      'status': 'pending',
    });
    debugPrint("Task of type '$type' has been queued for background processing.");
  }

  /// Adds a failed API request to the local database queue.
  Future<void> addApiToQueue({
    required String endpoint,
    required String method,
    Map<String, dynamic>? body,
    Map<String, String>? fields,
    Map<String, File>? files,
  }) async {
    // Convert File objects to paths for JSON serialization
    final serializableFiles = files?.map((key, value) => MapEntry(key, value.path));
    final payload = {
      'method': method,
      'body': body,
      'fields': fields,
      'files': serializableFiles, // Store paths instead of File objects
    };
    await _dbHelper.queueFailedRequest({
      'type': 'api',
      'endpoint_or_path': endpoint,
      'payload': jsonEncode(payload),
      'timestamp': DateTime.now().toIso8601String(),
      'status': 'pending',
    });
    debugPrint("API request for endpoint '$endpoint' has been queued for retry.");
  }

  /// Adds a failed FTP upload to the local database queue.
  Future<void> addFtpToQueue({
    required String localFilePath,
    required String remotePath,
    required int ftpConfigId, // Added to specify which destination failed
  }) async {
    final payload = {
      'localFilePath': localFilePath,
      'ftpConfigId': ftpConfigId, // Store the specific config ID
    };
    await _dbHelper.queueFailedRequest({
      'type': 'ftp',
      'endpoint_or_path': remotePath,
      'payload': jsonEncode(payload),
      'timestamp': DateTime.now().toIso8601String(),
      'status': 'pending',
    });
    debugPrint("FTP upload for file '$localFilePath' to config ID $ftpConfigId has been queued for retry.");
  }


  /// Retrieves all tasks currently in the 'pending' state from the queue.
  Future<List<Map<String, dynamic>>> getPendingTasks() {
    return _dbHelper.getPendingRequests();
  }

  /// Processes the entire queue of pending tasks.
  Future<void> processRetryQueue() async {
    if (_isProcessing) {
      debugPrint("[RetryService] ⏳ Queue is already being processed. Skipping.");
      return;
    }
    _isProcessing = true;
    debugPrint("[RetryService] ▶️ Starting to process main retry queue...");

    final pendingTasks = await getPendingTasks();
    if (pendingTasks.isEmpty) {
      debugPrint("[RetryService] ⏹️ Queue is empty. Nothing to process.");
      _isProcessing = false;
      return;
    }

    // Check internet connection *before* processing
    if (_authProvider == null || !await _authProvider!.isConnected()) {
      debugPrint("[RetryService] ❌ No internet connection. Aborting queue processing.");
      _isProcessing = false;
      return;
    }

    debugPrint("[RetryService] 🔎 Found ${pendingTasks.length} pending tasks.");
    // Process tasks one by one
    for (final task in pendingTasks) {
      // Add safety check in case a task is deleted mid-processing by another call
      if (await _dbHelper.getRequestById(task['id'] as int) != null) {
        await retryTask(task['id'] as int);
      }
      // Optional: Add a small delay between tasks if needed
      // await Future.delayed(Duration(seconds: 1));
    }

    debugPrint("[RetryService] ⏹️ Finished processing retry queue.");
    _isProcessing = false;
  }

  /// Attempts to re-execute a single failed task from the queue.
  /// Returns `true` on success, `false` on failure.
  Future<bool> retryTask(int taskId) async {
    final task = await _dbHelper.getRequestById(taskId);
    if (task == null) {
      debugPrint("Retry failed: Task with ID $taskId not found in the queue (might have been processed already).");
      return false; // Task doesn't exist or was processed elsewhere
    }

    bool success = false;
    Map<String, dynamic> payload; // Declare outside try-catch
    final String taskType = task['type'] as String; // Get type early for logging

    try {
      payload = jsonDecode(task['payload'] as String); // Decode payload inside try
    } catch (e) {
      debugPrint("Error decoding payload for task $taskId (Type: $taskType): $e. Removing invalid task.");
      await _dbHelper.deleteRequestFromQueue(taskId);
      return false; // Cannot process without valid payload
    }


    try {
      // Ensure AuthProvider is initialized and we are online (checked in processRetryQueue)
      if (_authProvider == null) {
        debugPrint("RetryService has not been initialized. Cannot process task $taskId.");
        return false;
      }

      // --- Complex Task Handlers ---
      if (taskType == 'insitu_submission') {
        debugPrint("Retrying complex task 'insitu_submission' with ID $taskId.");
        if (_marineInSituService == null) {
          debugPrint("Retry failed: MarineInSituSamplingService not initialized.");
          return false;
        }

        final String logDirectoryPath = payload['localLogPath']; // Path to the directory
        final jsonFilePath = p.join(logDirectoryPath, 'data.json');
        final file = File(jsonFilePath);

        if (!await file.exists()) {
          debugPrint("Retry failed: Source log file no longer exists at $jsonFilePath");
          await _dbHelper.deleteRequestFromQueue(taskId); // Remove invalid task
          return false;
        }

        final content = await file.readAsString();
        final jsonData = jsonDecode(content) as Map<String, dynamic>;
        final InSituSamplingData dataToResubmit = InSituSamplingData.fromJson(jsonData);

        // Re-run the original submission logic, passing the log directory
        final result = await _marineInSituService!.submitInSituSample(
          data: dataToResubmit,
          appSettings: _authProvider!.appSettings, // Get current settings
          authProvider: _authProvider!,
          logDirectory: logDirectoryPath, // Pass directory to update log
        );
        success = result['success'];

      } else if (taskType == 'river_insitu_submission') {
        debugPrint("Retrying complex task 'river_insitu_submission' with ID $taskId.");
        if (_riverInSituService == null) {
          debugPrint("Retry failed: RiverInSituSamplingService not initialized.");
          return false;
        }

        final String jsonFilePath = payload['localLogPath']; // Path to the JSON file
        final file = File(jsonFilePath);

        if (!await file.exists()) {
          debugPrint("Retry failed: Source log file no longer exists at $jsonFilePath");
          await _dbHelper.deleteRequestFromQueue(taskId);
          return false;
        }
        final String logDirectoryPath = p.dirname(jsonFilePath); // Get directory from file path


        final content = await file.readAsString();
        final jsonData = jsonDecode(content) as Map<String, dynamic>;
        final RiverInSituSamplingData dataToResubmit = RiverInSituSamplingData.fromJson(jsonData);

        final result = await _riverInSituService!.submitData(
          data: dataToResubmit,
          appSettings: _authProvider!.appSettings,
          authProvider: _authProvider!,
          logDirectory: logDirectoryPath,
        );
        success = result['success'];

        // *** ADDED: Handler for river_investigative_submission ***
      } else if (taskType == 'river_investigative_submission') {
        debugPrint("Retrying complex task 'river_investigative_submission' with ID $taskId.");
        if (_riverInvestigativeService == null) {
          debugPrint("Retry failed: RiverInvestigativeSamplingService not initialized.");
          return false;
        }

        final String jsonFilePath = payload['localLogPath']; // Path to the JSON file
        final file = File(jsonFilePath);

        if (!await file.exists()) {
          debugPrint("Retry failed: Source log file no longer exists at $jsonFilePath");
          await _dbHelper.deleteRequestFromQueue(taskId);
          return false;
        }
        final String logDirectoryPath = p.dirname(jsonFilePath); // Get directory from file path

        final content = await file.readAsString();
        final jsonData = jsonDecode(content) as Map<String, dynamic>;
        // Use the correct Investigative data model
        final RiverInvesManualSamplingData dataToResubmit = RiverInvesManualSamplingData.fromJson(jsonData);

        // Call the submitData method from the Investigative service
        final result = await _riverInvestigativeService!.submitData(
          data: dataToResubmit,
          appSettings: _authProvider!.appSettings,
          authProvider: _authProvider!,
          logDirectory: logDirectoryPath,
        );
        success = result['success'];
        // *** END ADDED ***

      } else if (taskType == 'investigative_submission') {
        debugPrint("Retrying complex task 'investigative_submission' with ID $taskId.");
        if (_marineInvestigativeService == null) {
          debugPrint("Retry failed: MarineInvestigativeSamplingService not initialized.");
          return false;
        }

        final String logDirectoryPath = payload['localLogPath']; // Path to the directory
        final jsonFilePath = p.join(logDirectoryPath, 'data.json');
        final file = File(jsonFilePath);

        if (!await file.exists()) {
          debugPrint("Retry failed: Source log file no longer exists at $jsonFilePath");
          await _dbHelper.deleteRequestFromQueue(taskId);
          return false;
        }

        final content = await file.readAsString();
        final jsonData = jsonDecode(content) as Map<String, dynamic>;
        final MarineInvesManualSamplingData dataToResubmit = MarineInvesManualSamplingData.fromJson(jsonData);

        final result = await _marineInvestigativeService!.submitInvestigativeSample(
          data: dataToResubmit,
          appSettings: _authProvider!.appSettings,
          authProvider: _authProvider!,
          logDirectory: logDirectoryPath,
        );
        success = result['success'];

      } else if (taskType == 'tarball_submission') {
        debugPrint("Retrying complex task 'tarball_submission' with ID $taskId.");
        if (_marineTarballService == null) {
          debugPrint("Retry failed: MarineTarballSamplingService not initialized.");
          return false;
        }

        final String logDirectoryPath = payload['localLogPath']; // Path to the directory
        final jsonFilePath = p.join(logDirectoryPath, 'data.json');
        final file = File(jsonFilePath);

        if (!await file.exists()) {
          debugPrint("Retry failed: Source log file no longer exists at $jsonFilePath");
          await _dbHelper.deleteRequestFromQueue(taskId);
          return false;
        }

        final content = await file.readAsString();
        final jsonData = jsonDecode(content) as Map<String, dynamic>;

        // Recreate File objects from paths
        File? fileFromJson(dynamic path) => (path is String && path.isNotEmpty) ? File(path) : null;

        final TarballSamplingData dataToResubmit = TarballSamplingData()
        // Reconstruct the object from JSON data
          ..firstSampler = jsonData['firstSampler']
          ..firstSamplerUserId = jsonData['firstSamplerUserId']
          ..secondSampler = jsonData['secondSampler']
          ..samplingDate = jsonData['samplingDate']
          ..samplingTime = jsonData['samplingTime']
          ..selectedStateName = jsonData['selectedStateName']
          ..selectedCategoryName = jsonData['selectedCategoryName']
          ..selectedStation = jsonData['selectedStation']
          ..stationLatitude = jsonData['stationLatitude']
          ..stationLongitude = jsonData['stationLongitude']
          ..currentLatitude = jsonData['currentLatitude']
          ..currentLongitude = jsonData['currentLongitude']
          ..distanceDifference = jsonData['distanceDifference'] is num ? (jsonData['distanceDifference'] as num).toDouble() : null // Safe cast
          ..distanceDifferenceRemarks = jsonData['distanceDifferenceRemarks']
          ..classificationId = jsonData['classificationId'] is num ? (jsonData['classificationId'] as num).toInt() : null // Safe cast
          ..selectedClassification = jsonData['selectedClassification']
          ..leftCoastalViewImage = fileFromJson(jsonData['leftCoastalViewImage'])
          ..rightCoastalViewImage = fileFromJson(jsonData['rightCoastalViewImage'])
          ..verticalLinesImage = fileFromJson(jsonData['verticalLinesImage'])
          ..horizontalLineImage = fileFromJson(jsonData['horizontalLineImage'])
          ..optionalImage1 = fileFromJson(jsonData['optionalImage1'])
          ..optionalRemark1 = jsonData['optionalRemark1']
          ..optionalImage2 = fileFromJson(jsonData['optionalImage2'])
          ..optionalRemark2 = jsonData['optionalRemark2']
          ..optionalImage3 = fileFromJson(jsonData['optionalImage3'])
          ..optionalRemark3 = jsonData['optionalRemark3']
          ..optionalImage4 = fileFromJson(jsonData['optionalImage4'])
          ..optionalRemark4 = jsonData['optionalRemark4']
          ..reportId = jsonData['reportId'] // Preserve reportId if it exists
          ..submissionStatus = jsonData['submissionStatus'] // Preserve status info
          ..submissionMessage = jsonData['submissionMessage'];


        debugPrint("Retrying Tarball submission...");
        // Pass null for BuildContext, and the logDirectory path
        final result = await _marineTarballService!.submitTarballSample(
          data: dataToResubmit,
          appSettings: _authProvider!.appSettings,
          context: null, // Pass null for BuildContext during retry
          logDirectory: logDirectoryPath, // Pass the directory path for potential update
        );
        success = result['success'];

        // --- Simple Task Handlers ---
      } else if (taskType == 'api') {
        final endpoint = task['endpoint_or_path'] as String;
        final method = payload['method'] as String;
        final baseUrl = await _serverConfigService.getActiveApiUrl(); // Get current active URL
        debugPrint("Retrying API task $taskId: $method to $baseUrl/$endpoint");
        Map<String, dynamic> result;

        if (method == 'POST_MULTIPART') {
          final Map<String, String> fields = Map<String, String>.from(payload['fields'] ?? {});
          // Recreate File objects from paths stored in the payload
          final Map<String, File> files = (payload['files'] as Map<String, dynamic>?)
              ?.map((key, value) => MapEntry(key, File(value as String))) ?? {};

          // Check if files still exist before attempting upload
          bool allFilesExist = true;
          List<String> missingFiles = []; // Keep track of missing files
          for (var entry in files.entries) {
            File file = entry.value;
            if (!await file.exists()) {
              debugPrint("Retry failed for API task $taskId: File ${file.path} (key: ${entry.key}) no longer exists.");
              allFilesExist = false;
              missingFiles.add(entry.key);
              // break; // Stop checking further if one is missing
            }
          }

          // If some files are missing, fail the entire task.
          if (!allFilesExist) {
            debugPrint("API Multipart retry failed for task $taskId because files are missing: ${missingFiles.join(', ')}. Removing task.");
            await _dbHelper.deleteRequestFromQueue(taskId); // Remove invalid task
            return false;
          }

          result = await _baseApiService.postMultipart(baseUrl: baseUrl, endpoint: endpoint, fields: fields, files: files);
        } else { // Standard POST
          final Map<String, dynamic> body = Map<String, dynamic>.from(payload['body'] ?? {});
          result = await _baseApiService.post(baseUrl, endpoint, body);
        }
        success = result['success'];

      } else if (taskType == 'ftp') {
        final remotePath = task['endpoint_or_path'] as String;
        final localFile = File(payload['localFilePath'] as String);
        final int? ftpConfigId = payload['ftpConfigId'] as int?;

        debugPrint("Retrying FTP task $taskId: Uploading ${localFile.path} to $remotePath using config ID $ftpConfigId");

        if (ftpConfigId == null) {
          debugPrint("Retry failed for FTP task $taskId: Missing FTP configuration ID in payload.");
          await _dbHelper.deleteRequestFromQueue(taskId); // Remove invalid task
          return false;
        }

        if (await localFile.exists()) {
          final ftpConfigs = await _dbHelper.loadFtpConfigs() ?? [];
          final config = ftpConfigs.firstWhere((c) => c['ftp_config_id'] == ftpConfigId, orElse: () => <String, dynamic>{}); // Use explicit type


          if (config.isEmpty) {
            debugPrint("Retry failed for FTP task $taskId: FTP configuration with ID $ftpConfigId not found.");
            return false; // Fail the retry attempt, keep in queue
          }

          // Attempt upload using the specific config
          final result = await _ftpService.uploadFile(config: config, fileToUpload: localFile, remotePath: remotePath);
          success = result['success'];

        } else {
          debugPrint("Retry failed for FTP task $taskId: Source file no longer exists at ${localFile.path}");
          await _dbHelper.deleteRequestFromQueue(taskId); // Remove task if file is gone
          return false; // Explicitly return false as success is false
        }
      } else {
        debugPrint("Unknown task type '$taskType' for task ID $taskId. Cannot retry. Removing task.");
        await _dbHelper.deleteRequestFromQueue(taskId);
      }

    } on SessionExpiredException catch (e) {
      debugPrint("Session expired during retry attempt for task $taskId (Type: $taskType): $e. Task remains in queue.");
      success = false; // Session expiry during retry means failure for this attempt
    } catch (e, stacktrace) { // Catch potential exceptions during processing
      debugPrint("A critical error occurred while retrying task $taskId (Type: $taskType): $e");
      debugPrint("Stacktrace: $stacktrace"); // Log stacktrace for detailed debugging
      success = false; // Ensure success is false on exception
    }

    // Post-processing: Remove successful tasks from queue
    if (success) {
      debugPrint("Task $taskId (Type: $taskType) completed successfully. Removing from queue.");
      await _dbHelper.deleteRequestFromQueue(taskId);
      // If it was a complex task involving temporary ZIP files, attempt to delete them
      if (taskType.endsWith('_submission') && payload['localLogPath'] != null) {
        // Assume localLogPath points to the JSON file, get directory for cleanup
        String pathToCheck = payload['localLogPath'];
        // Check if it's a directory path already (for older marine insitu logs)
        bool isDirectory = await Directory(pathToCheck).exists();
        if (!isDirectory && pathToCheck.endsWith('.json')) {
          pathToCheck = p.dirname(pathToCheck); // Get directory if it's a file path
          isDirectory = true; // Now we are checking the directory
        }
        _cleanUpTemporaryZipFiles(pathToCheck, isDirectory: isDirectory);
      }
      // If it was an FTP task, attempt to delete the temporary ZIP file
      if (taskType == 'ftp' && payload['localFilePath'] != null && (payload['localFilePath'] as String).endsWith('.zip')) {
        _cleanUpTemporaryZipFiles(payload['localFilePath'], isDirectory: false);
      }

    } else {
      debugPrint("Retry attempt for task $taskId (Type: $taskType) failed. It will remain in the queue.");
      // Optional: Implement a retry limit here. If retries > X, mark task as 'failed' instead of 'pending'.
      // e.g., await _dbHelper.updateTaskStatus(taskId, 'failed');
    }

    return success;
  }

  /// Helper function to delete temporary zip files after successful retry.
  void _cleanUpTemporaryZipFiles(String path, {required bool isDirectory}) async {
    try {
      if (isDirectory) {
        final dir = Directory(path);
        if (await dir.exists()) {
          final filesInDir = dir.listSync();
          for (var entity in filesInDir) {
            // Delete only ZIP files within the log directory
            if (entity is File && entity.path.endsWith('.zip')) {
              debugPrint("Deleting temporary zip file from directory: ${entity.path}");
              await entity.delete();
            }
          }
          // Optional: Delete the directory itself if now empty, ONLY if safe.
          // Be cautious as data.json might still be needed or other files exist.
          // if (await dir.listSync().isEmpty) {
          //    await dir.delete();
          //    debugPrint("Deleted empty log directory: ${dir.path}");
          // }
        } else {
          debugPrint("Log directory not found for cleanup: $path");
        }
      } else {
        // If it's a specific file path (like from FTP task)
        final file = File(path);
        if (await file.exists() && path.endsWith('.zip')) { // Ensure it's a zip file
          debugPrint("Deleting temporary zip file: ${file.path}");
          await file.delete();
        } else if (!path.endsWith('.zip')) {
          debugPrint("Skipping cleanup for non-zip file path: $path");
        } else {
          debugPrint("Temporary zip file not found for cleanup: $path");
        }
      }
    } catch (e) {
      debugPrint("Error cleaning up temporary zip file(s) for path $path: $e");
    }
  }

} // End of RetryService class