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

import 'package:ffi/ffi.dart';

import 'deezcryptor_bindings_generated.dart';

const String _libName = 'deezcryptor';

/// The dynamic library in which the symbols for [DeezcryptorBindings] can be found.
final ffi.DynamicLibrary _dylib = () {
  if (Platform.isMacOS || Platform.isIOS) {
    return ffi.DynamicLibrary.open('$_libName.framework/$_libName');
  }
  if (Platform.isAndroid || Platform.isLinux) {
    return ffi.DynamicLibrary.open('lib$_libName.so');
  }
  if (Platform.isWindows) {
    return ffi.DynamicLibrary.open('$_libName.dll');
  }

  throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
}();

/// The bindings to the native functions in [_dylib].
final DeezcryptorBindings _bindings = DeezcryptorBindings(_dylib);

final decryptChunkRaw = _bindings.decryptChunk;

List<int> decryptChunk(List<int> data, List<int> key) {
  final ptr = malloc<ffi.Char>(data.length);
  final ptr1 = listIntToPointerChar(data);
  final ptr2 = listIntToPointerChar(key);
  final size = _bindings.decryptChunk(ptr, ptr1, ptr2);
  malloc.free(ptr1);
  malloc.free(ptr2);
  final dec = pointerCharToListInt(ptr, size);
  malloc.free(ptr);
  return dec;
}

ffi.Pointer<ffi.Char> listIntToPointerChar<T>(List<int> list) {
  final length = list.length;
  final ptr = malloc<ffi.Char>(length);
  for (int i = 0; i < length; i++) {
    ptr[i] = list[i];
  }

  return ptr;
}

List<int> pointerCharToListInt(ffi.Pointer<ffi.Char> ptr, int size) {
  return List<int>.unmodifiable(
      Iterable<int>.generate(size, (index) => ptr[index]));
}