import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:worldhopper/models/koreader_progress.dart';
import 'package:worldhopper/models/opds_server.dart';
import 'package:worldhopper/providers/server_provider.dart';
import 'package:worldhopper/services/koreader_sync_service.dart';

/// Provider for creating a KoreaderSyncService for a given server.
/// Only returns a service if the server has KOReader sync enabled.
final koreaderSyncServiceProvider =
    Provider.family<KoreaderSyncService?, OPDSServer>((ref, server) {
  if (!server.koreaderSyncEnabled ||
      server.koreaderSyncUrl == null ||
      server.koreaderSyncUrl!.isEmpty) {
    return null;
  }
  return KoreaderSyncService(server);
});

/// Provider to get a KoreaderSyncService by server ID.
/// Returns null if server not found or KOReader sync is not enabled.
final koreaderSyncServiceByIdProvider =
    FutureProvider.family<KoreaderSyncService?, String>((ref, serverId) async {
  final server = await ref.watch(serverProvider(serverId).future);
  if (server == null) return null;
  return ref.watch(koreaderSyncServiceProvider(server));
});

/// Push reading progress to KOReader sync server.
/// Returns true if sync was successful, false otherwise.
/// Fails silently (logs error) to not interrupt the reading experience.
Future<bool> pushKoreaderProgress({
  required KoreaderSyncService syncService,
  required String documentHash,
  required double percentage,
  required String progress,
}) async {
  try {
    return await syncService.updateProgress(
      documentHash: documentHash,
      percentage: percentage,
      progress: progress,
    );
  } on KoreaderSyncAuthException {
    rethrow;
  } catch (e) {
    debugPrint('Failed to push KOReader progress: $e');
    return false;
  }
}

/// Pull reading progress from KOReader sync server.
/// Returns the remote progress if available, null otherwise.
Future<KoreaderProgress?> pullKoreaderProgress({
  required KoreaderSyncService syncService,
  required String documentHash,
}) async {
  try {
    return await syncService.getProgress(documentHash);
  } on KoreaderSyncAuthException {
    rethrow;
  } catch (e) {
    debugPrint('Failed to pull KOReader progress: $e');
    return null;
  }
}

/// Compute the document hash for a given entry.
/// If the EPUB file is available, uses the file's partial MD5 hash (compatible with KOReader).
/// Falls back to hashing the OPDS entry ID.
Future<String> computeDocumentHash({
  required String entryId,
  File? epubFile,
}) async {
  if (epubFile != null && await epubFile.exists()) {
    return await KoreaderSyncService.computeFileHash(epubFile);
  }
  return KoreaderSyncService.computeStringHash(entryId);
}