import 'dart:convert';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:iperf3gui/domain/models/iperf3_result.dart';
import 'package:iperf3gui/domain/models/test_configuration.dart';

/// Service that runs iperf3 via [Process.start] and captures output.
class Iperf3Service {
  final String _binaryPath;

  // ignore: prefer_initializing_formals
  Iperf3Service({required String binaryPath}) : _binaryPath = binaryPath;

  /// Run iperf3 with the given configuration.
  ///
  /// Returns an [Iperf3Result] with stdout/stderr and exit code.
  Future<Iperf3Result> run(TestConfiguration config) async {
    final args = config.toCliArgs();

    debugPrint(
      'Iperf3Service: running $_binaryPath ${args.join(" ")}',
    );

    final process = await Process.start(
      _binaryPath,
      args,
      runInShell: false, // must execve directly — Android sh can't exec ELF binaries
    );

    final stdoutBuffer = <int>[];
    final stderrBuffer = <int>[];

    final stdoutStream = process.stdout.transform(utf8.decoder).listen(
      (data) {
        stdoutBuffer.addAll(utf8.encode(data));
        debugPrint('Iperf3Service stdout: $data');
      },
    );
    final stderrStream = process.stderr.transform(utf8.decoder).listen(
      (data) {
        stderrBuffer.addAll(utf8.encode(data));
        debugPrint('Iperf3Service stderr: $data');
      },
    );

    final exitCode = await process.exitCode;

    await stdoutStream.cancel();
    await stderrStream.cancel();

    final rawOutput = utf8.decode(stdoutBuffer) + utf8.decode(stderrBuffer);

    debugPrint(
      'Iperf3Service: finished with exit code $exitCode, output length ${rawOutput.length}',
    );

    return Iperf3Result(
      rawOutput: rawOutput,
      exitCode: exitCode,
    );
  }
}