import 'dart:ffi';
import 'dart:io';

import 'package:logger/logger.dart';
import 'package:path/path.dart' as p;

import 'platform_adapter.dart';

class NativeLibraryLoader {
  NativeLibraryLoader({
    required this.logger,
    PlatformAdapter? adapter,
  }) : _adapter = adapter ?? const PlatformAdapter();

  final Logger logger;
  final PlatformAdapter _adapter;

  DynamicLibrary load() {
    final overridePath =
        Platform.environment['PEYA_WALLET_LIB'] ?? Platform.environment['SALVIUM_WALLET_LIB'];
    if (overridePath != null && overridePath.isNotEmpty) {
      return _loadFromPath(overridePath);
    }

    for (final root in _adapter.librarySearchPaths()) {
      for (final libName in _adapter.libraryNames()) {
        final candidate = p.join(Directory.current.path, root, libName);
        if (File(candidate).existsSync()) {
          logger.i('Loading wallet library from $candidate');
          return DynamicLibrary.open(candidate);
        }
      }
    }

    logger.w('Wallet library not found in search paths. Falling back.');
    throw StateError('Wallet library not found. Set PEYA_WALLET_LIB or build native wrapper.');
  }

  DynamicLibrary _loadFromPath(String path) {
    final resolved = p.normalize(path);
    if (!File(resolved).existsSync()) {
      throw StateError('Wallet library not found at $resolved');
    }
    logger.i('Loading wallet library from $resolved');
    return DynamicLibrary.open(resolved);
  }
}