import 'dart:io';
import 'dart:math';

import 'package:file_picker/file_picker.dart';
import 'package:http/http.dart' as http;

class SelectedAudio {
  const SelectedAudio({required this.name, required this.path});

  final String name;
  final String path;
}

Future<SelectedAudio?> pickAudio(List<String> supportedExtensions) async {
  final result = await FilePicker.platform.pickFiles(
    type: FileType.custom,
    allowedExtensions: supportedExtensions,
    allowMultiple: false,
  );

  final pickedFile = result?.files.single;
  final path = pickedFile?.path;
  if (pickedFile == null || path == null) {
    return null;
  }

  return SelectedAudio(name: pickedFile.name, path: path);
}

Future<SelectedAudio?> audioFromRecorderPath(
  String path,
  String fallbackName,
) async {
  return SelectedAudio(
    name: path.split(Platform.pathSeparator).last,
    path: path,
  );
}

Future<List<double>> buildWavePreview(SelectedAudio audio) async {
  final bytes = await File(audio.path).readAsBytes();
  return _wavePoints(bytes);
}

Future<http.MultipartFile> multipartFileFromAudio(
  String fieldName,
  SelectedAudio audio,
) {
  return http.MultipartFile.fromPath(fieldName, audio.path);
}

String recordingFilePath(String fileName) {
  return '${Directory.systemTemp.path}${Platform.pathSeparator}$fileName';
}

List<double> _wavePoints(List<int> bytes) {
  if (bytes.isEmpty) {
    return const [];
  }

  const pointCount = 96;
  final step = max(1, bytes.length ~/ pointCount);
  final points = <double>[];

  for (var index = 0; index < bytes.length; index += step) {
    final normalized = (bytes[index] - 128) / 128.0;
    points.add(normalized.clamp(-1.0, 1.0));
    if (points.length == pointCount) {
      break;
    }
  }

  return points;
}