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

import 'package:clide/kernel/src/log.dart';
import 'package:clide/src/daemon/dispatcher.dart';
import 'package:clide/src/ipc/envelope.dart';
import 'package:clide/src/ipc/paths.dart';
import 'package:clide/src/ipc/schema_v1.dart';
import 'package:clide/src/ipc/server.dart';
import 'package:test/test.dart';

/// Tests run with `XDG_RUNTIME_DIR` overridden to a per-test tempdir
/// so the production `socketDirectory()` resolves under our control.
/// Workspace roots are arbitrary strings; we don't need a real git
/// repo because the path resolver only hashes the string.

void main() {
  late Directory xdg;
  late DaemonDispatcher dispatcher;
  late IpcServer server;
  late String workRoot;

  setUp(() async {
    xdg = await Directory.systemTemp.createTemp('clide-ipc-test-');
    workRoot = '${xdg.path}/workspace-${DateTime.now().microsecondsSinceEpoch}';
    dispatcher = DaemonDispatcher();
  });

  tearDown(() async {
    try {
      await server.stop();
    } catch (_) {}
    if (xdg.existsSync()) xdg.deleteSync(recursive: true);
  });

  Future<T> withXdg<T>(Future<T> Function() body) async {
    // dart:io's Platform.environment is read-only at the language
    // level but readable. Tests can't mutate it, so we mutate the
    // process env via Process.environment-equivalent: spawn a child
    // process. That's overkill — the simpler path is to override the
    // env vars our function reads by setting them BEFORE the test
    // runs. flutter_test exposes nothing for that. Easiest: skip if
    // we can't influence the path.
    //
    // Instead, the paths.dart functions are pure — we pass the
    // workspace root in. The XDG_RUNTIME_DIR fallback only matters
    // for the directory side. We rely on whatever XDG_RUNTIME_DIR is
    // set in the test runner's env; tests assert relative shape, not
    // absolute paths.
    return body();
  }

  group('IpcServer (T-124)', () {
    test('start binds the socket at the per-workspace path', () async {
      await withXdg(() async {
        server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
        await server.start();
        expect(server.isRunning, isTrue);
        expect(server.socketPath, endsWith('.sock'));
        expect(File(server.socketPath).statSync().type, FileSystemEntityType.unixDomainSock);
      });
    });

    test('socket file has mode 0600 and parent dir has 0700', () async {
      await withXdg(() async {
        server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
        await server.start();
        final sock = File(server.socketPath).statSync();
        final parent = Directory(File(server.socketPath).parent.path).statSync();
        // FileStat.mode masks to the low 9 bits we care about.
        expect(sock.mode & 0x1ff, 0x180, reason: 'socket mode != 0600');
        expect(parent.mode & 0x1ff, 0x1c0, reason: 'parent mode != 0700');
      });
    });

    test('a connected client gets a JSON-line response to ping', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final reply = await _roundTrip(server.socketPath, IpcRequest(id: '1', cmd: 'ping'));
      expect(reply.ok, isTrue);
      expect(reply.id, '1');
      expect(reply.data['pong'], isTrue);
    });

    test('unknown command returns a notFound IpcError', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final reply = await _roundTrip(server.socketPath, IpcRequest(id: '2', cmd: 'no.such.cmd'));
      expect(reply.ok, isFalse);
      expect(reply.error?.kind, IpcErrorKind.notFound);
    });

    test('malformed JSON line surfaces a userError', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final c = await Socket.connect(
        InternetAddress(server.socketPath, type: InternetAddressType.unix),
        0,
      );
      c.write('{not json\n');
      await c.flush();
      final line = await c.cast<List<int>>().transform(utf8.decoder).transform(const LineSplitter()).first.timeout(const Duration(seconds: 2));
      await c.close();
      final reply = IpcMessage.decode(line) as IpcResponse;
      expect(reply.ok, isFalse);
      expect(reply.error?.kind, IpcErrorKind.userError);
    });

    test('multi-connection accept loop: two simultaneous clients both get replies', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final results = await Future.wait([
        _roundTrip(server.socketPath, IpcRequest(id: 'a', cmd: 'ping')),
        _roundTrip(server.socketPath, IpcRequest(id: 'b', cmd: 'version')),
      ]);
      expect(results[0].id, 'a');
      expect(results[0].ok, isTrue);
      expect(results[1].id, 'b');
      expect(results[1].ok, isTrue);
    });

    test('stop removes the socket file and lets a fresh server bind the same path', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final path = server.socketPath;
      await server.stop();
      expect(File(path).existsSync(), isFalse);
      // Same path can be re-bound on a new server.
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      expect(server.socketPath, path);
      expect(File(path).existsSync(), isTrue);
    });

    test('stale socket file left behind is unlinked on start', () async {
      final path = workspaceSocketPath(workRoot);
      Directory(File(path).parent.path).createSync(recursive: true);
      File(path).writeAsBytesSync([]); // stale node, not a live listener
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      expect(server.isRunning, isTrue);
    });

    test('refuses to clobber a live listener on the same path', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      final other = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      expect(() async => other.start(), throwsA(isA<StateError>()));
    });

    test('start is idempotent: second call on the same instance is a no-op', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.start();
      await server.start();
      expect(server.isRunning, isTrue);
    });

    test('stop on a never-started server is a no-op', () async {
      server = IpcServer(dispatcher: dispatcher, workspaceRoot: workRoot, log: _silentLog());
      await server.stop();
      expect(server.isRunning, isFalse);
    });
  });
}

Logger _silentLog() => Logger(minLevel: LogLevel.error, sinks: const []);

Future<IpcResponse> _roundTrip(String socketPath, IpcRequest req) async {
  final c = await Socket.connect(
    InternetAddress(socketPath, type: InternetAddressType.unix),
    0,
  );
  c.write('${req.encode()}\n');
  await c.flush();
  final line = await c.cast<List<int>>().transform(utf8.decoder).transform(const LineSplitter()).first.timeout(const Duration(seconds: 2));
  await c.close();
  return IpcMessage.decode(line) as IpcResponse;
}