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

import 'package:ffi/ffi.dart';
import 'package:flutter_example/generated_bindings.dart';

class Bindings {
  static Bindings? _instance;

  final NativeLibrary library;

  Bindings._(NativeLibrary lib) : library = lib;

  /// Load from lib
  static Bindings init(String libName) {
    /// The dynamic library in which the symbols for [NativeAddBindings] can be found.
    final DynamicLibrary dylib = () {
      if (Platform.isMacOS || Platform.isIOS) {
        return DynamicLibrary.open('$libName.framework/$libName');
      }
      if (Platform.isAndroid || Platform.isLinux) {
        return DynamicLibrary.open('lib$libName.so');
      }
      if (Platform.isWindows) {
        return DynamicLibrary.open('$libName.dll');
      }
      throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
    }.call();

    /// The bindings to the native functions in [_dylib].
    return _instance ??= Bindings._(NativeLibrary(dylib));
  }

  static Bindings get instance => _instance!;

  static int sum(int a, int b) {
    final hello = instance.library.MyLib_Hello_Create(nullptr);

    final result = instance.library.MyLib_Hello_Sum(hello, a, b, nullptr);

    return result;
  }
}