// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library service_test_common;

import 'dart:async';
import 'dart:io' show Platform;
import 'package:dds/dds.dart';
import 'package:observatory/models.dart' as M;
import 'package:observatory/service_common.dart';
import 'package:observatory/service_io.dart';
import 'package:test/test.dart';

typedef Future IsolateTest(Isolate isolate);
typedef Future VMTest(VM vm);
typedef Future DDSTest(VM vm, DartDevelopmentService dds);
typedef void ServiceEventHandler(ServiceEvent event);

Map<String, StreamSubscription> streamSubscriptions = {};

Future subscribeToStream(
    VM vm, String streamName, ServiceEventHandler onEvent) async {
  assert(streamSubscriptions[streamName] == null);

  Stream<ServiceEvent> stream = await vm.getEventStream(streamName);
  StreamSubscription subscription = stream.listen(onEvent);
  streamSubscriptions[streamName] = subscription;
}

Future cancelStreamSubscription(String streamName) async {
  StreamSubscription subscription = streamSubscriptions[streamName]!;
  subscription.cancel();
  streamSubscriptions.remove(streamName);
}

Future smartNext(Isolate isolate) async {
  print('smartNext');
  if (isolate.status == M.IsolateStatus.paused) {
    dynamic event = isolate.pauseEvent;
    if (event.atAsyncSuspension) {
      return asyncNext(isolate);
    } else {
      return syncNext(isolate);
    }
  } else {
    throw 'The program is already running';
  }
}

Future asyncNext(Isolate isolate) async {
  print('asyncNext');
  if (isolate.status == M.IsolateStatus.paused) {
    dynamic event = isolate.pauseEvent;
    if (!event.atAsyncSuspension) {
      throw 'No async continuation at this location';
    } else {
      return isolate.stepOverAsyncSuspension();
    }
  } else {
    throw 'The program is already running';
  }
}

Future syncNext(Isolate isolate) async {
  print('syncNext');
  if (isolate.status == M.IsolateStatus.paused) {
    return isolate.stepOver();
  } else {
    throw 'The program is already running';
  }
}

Future asyncStepOver(Isolate isolate) async {
  final Completer pausedAtSyntheticBreakpoint = new Completer();
  StreamSubscription? subscription;

  // Cancel the subscription.
  cancelSubscription() {
    if (subscription != null) {
      subscription!.cancel();
      subscription = null;
    }
  }

  // Complete futures with with error.
  completeError(error) {
    if (!pausedAtSyntheticBreakpoint.isCompleted) {
      pausedAtSyntheticBreakpoint.completeError(error);
    }
  }

  // Subscribe to the debugger event stream.
  Stream<ServiceEvent> stream;
  try {
    stream = await isolate.vm.getEventStream(VM.kDebugStream);
  } catch (e) {
    completeError(e);
    return pausedAtSyntheticBreakpoint.future;
  }

  Breakpoint? syntheticBreakpoint;

  subscription = stream.listen((ServiceEvent event) async {
    // Synthetic breakpoint add event. This is the first event we will
    // receive.
    bool isAdd = (event.kind == ServiceEvent.kBreakpointAdded) &&
        (event.breakpoint!.isSyntheticAsyncContinuation!) &&
        (event.owner == isolate);
    // Resume after synthetic breakpoint added. This is the second event
    // we will receive.
    bool isResume = (event.kind == ServiceEvent.kResume) &&
        (syntheticBreakpoint != null) &&
        (event.owner == isolate);
    // Paused at synthetic breakpoint. This is the third event we will
    // receive.
    bool isPaused = (event.kind == ServiceEvent.kPauseBreakpoint) &&
        (syntheticBreakpoint != null) &&
        (event.breakpoint == syntheticBreakpoint);
    if (isAdd) {
      syntheticBreakpoint = event.breakpoint;
    } else if (isResume) {
    } else if (isPaused) {
      pausedAtSyntheticBreakpoint.complete(isolate);
      syntheticBreakpoint = null;
      cancelSubscription();
    }
  });

  // Issue the step OverAwait command.
  try {
    await isolate.stepOverAsyncSuspension();
  } catch (e) {
    // This can fail when another client issued the same resume command
    // or another client has moved the isolate forward.
    cancelSubscription();
    completeError(e);
  }

  return pausedAtSyntheticBreakpoint.future;
}

bool isEventOfKind(M.Event? event, String kind) {
  switch (kind) {
    case ServiceEvent.kPauseBreakpoint:
      return event is M.PauseBreakpointEvent;
    case ServiceEvent.kPauseException:
      return event is M.PauseExceptionEvent;
    case ServiceEvent.kPauseExit:
      return event is M.PauseExitEvent;
    case ServiceEvent.kPauseStart:
      return event is M.PauseStartEvent;
    case ServiceEvent.kPausePostRequest:
      return event is M.PausePostRequestEvent;
    default:
      return false;
  }
}

Future hasPausedFor(Isolate isolate, String kind) {
  // Set up a listener to wait for breakpoint events.
  Completer? completer = new Completer();
  isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
    var subscription;
    subscription = stream.listen((ServiceEvent event) {
      if ((isolate == event.isolate) && (event.kind == kind)) {
        if (completer != null) {
          // Reload to update isolate.pauseEvent.
          print('Paused with $kind');
          subscription.cancel();
          completer!.complete(isolate.reload());
          completer = null;
        }
      }
    });

    // Pause may have happened before we subscribed.
    isolate.reload().then((_) {
      if ((isolate.pauseEvent != null) &&
          isEventOfKind(isolate.pauseEvent!, kind)) {
        // Already waiting at a breakpoint.
        if (completer != null) {
          print('Paused with $kind');
          subscription.cancel();
          completer!.complete(isolate);
          completer = null;
        }
      }
    });
  });

  return completer!.future; // Will complete when breakpoint hit.
}

Future hasStoppedAtBreakpoint(Isolate isolate) {
  return hasPausedFor(isolate, ServiceEvent.kPauseBreakpoint);
}

Future hasStoppedPostRequest(Isolate isolate) {
  return hasPausedFor(isolate, ServiceEvent.kPausePostRequest);
}

Future hasStoppedWithUnhandledException(Isolate isolate) {
  return hasPausedFor(isolate, ServiceEvent.kPauseException);
}

Future hasStoppedAtExit(Isolate isolate) {
  return hasPausedFor(isolate, ServiceEvent.kPauseExit);
}

Future hasPausedAtStart(Isolate isolate) {
  return hasPausedFor(isolate, ServiceEvent.kPauseStart);
}

Future markDartColonLibrariesDebuggable(Isolate isolate) async {
  await isolate.reload();
  for (Library lib in isolate.libraries) {
    await lib.load();
    if (lib.uri!.startsWith('dart:') && !lib.uri!.startsWith('dart:_')) {
      var setDebugParams = {
        'libraryId': lib.id,
        'isDebuggable': true,
      };
      await isolate.invokeRpcNoUpgrade('setLibraryDebuggable', setDebugParams);
    }
  }
  return isolate;
}

IsolateTest reloadSources([bool pause = false]) {
  return (Isolate isolate) async {
    Map<String, dynamic> params = <String, dynamic>{};
    if (pause) {
      params['pause'] = pause;
    }
    return isolate.invokeRpc('reloadSources', params);
  };
}

// Currying is your friend.
IsolateTest setBreakpointAtLine(int line) {
  return (Isolate isolate) async {
    print("Setting breakpoint for line $line");
    Library lib = await isolate.rootLibrary.load() as Library;
    Script script = lib.scripts.firstWhere((s) => s.uri == lib.uri);

    Breakpoint bpt = await isolate.addBreakpoint(script, line);
    print("Breakpoint is $bpt");
    expect(bpt, isNotNull);
    expect(bpt is Breakpoint, isTrue);
  };
}

IsolateTest setBreakpointAtLineColumn(int line, int column) {
  return (Isolate isolate) async {
    print("Setting breakpoint for line $line column $column");
    Library lib = await isolate.rootLibrary.load() as Library;
    Script script = lib.scripts.firstWhere((s) => s.uri == lib.uri);

    Breakpoint bpt = await isolate.addBreakpoint(script, line, column);
    print("Breakpoint is $bpt");
    expect(bpt, isNotNull);
    expect(bpt is Breakpoint, isTrue);
  };
}

IsolateTest setBreakpointAtUriAndLine(String uri, int line) {
  return (Isolate isolate) async {
    print("Setting breakpoint for line $line in $uri");
    Breakpoint bpt = await isolate.addBreakpointByScriptUri(uri, line);
    print("Breakpoint is $bpt");
    expect(bpt, isNotNull);
    expect(bpt is Breakpoint, isTrue);
  };
}

IsolateTest stoppedAtLine(int line) {
  return (Isolate isolate) async {
    print("Checking we are at line $line");

    // Make sure that the isolate has stopped.
    await isolate.reload();
    expect(isolate.pauseEvent is! M.ResumeEvent, isTrue);

    ServiceMap stack = await isolate.getStack();
    expect(stack.type, equals('Stack'));

    List frames = stack['frames'];
    expect(frames.length, greaterThanOrEqualTo(1));

    Frame top = frames[0];
    Script script = await top.location!.script.load() as Script;
    int? actualLine = script.tokenToLine(top.location!.tokenPos);
    if (actualLine != line) {
      StringBuffer sb = new StringBuffer();
      sb.write("Expected to be at line $line but actually at line $actualLine");
      sb.write("\nFull stack trace:\n");
      for (Frame f in stack['frames']) {
        sb.write(" $f [${await f.location!.getLine()}]\n");
      }
      throw sb.toString();
    } else {
      print('Program is stopped at line: $line');
    }
  };
}

IsolateTest stoppedInFunction(String functionName) {
  return (Isolate isolate) async {
    print("Checking we are in function: $functionName");

    ServiceMap stack = await isolate.getStack();
    expect(stack.type, equals('Stack'));

    List frames = stack['frames'];
    expect(frames.length, greaterThanOrEqualTo(1));

    Frame topFrame = frames[0];
    ServiceFunction function =
        await topFrame.function!.load() as ServiceFunction;
    String name = function.name!;
    final bool matches = name == functionName;
    if (!matches) {
      StringBuffer sb = new StringBuffer();
      sb.write("Expected to be in function $functionName but "
          "actually in function $name");
      sb.write("\nFull stack trace:\n");
      for (Frame f in frames) {
        await f.function!.load();
        await (f.function!.dartOwner as ServiceObject).load();
        String name = f.function!.name!;
        String ownerName = (f.function!.dartOwner as ServiceObject).name!;
        sb.write(" $f [$name] [$ownerName]\n");
      }
      throw sb.toString();
    } else {
      print('Program is stopped in function: $functionName');
    }
  };
}

IsolateTest hasLocalVarInTopAwaiterStackFrame(String varName) {
  return (Isolate isolate) async {
    print("Checking we have variable '$varName' in the top frame");

    // Make sure that the isolate has stopped.
    await isolate.reload();
    expect(isolate.pauseEvent is! M.ResumeEvent, isTrue);

    final ServiceMap stack = await isolate.getStack();
    expect(stack.type, equals('Stack'));

    final List frames = stack['awaiterFrames'];
    expect(frames.length, greaterThanOrEqualTo(1));

    final Frame top = frames[0];
    for (final variable in top.variables) {
      if (variable.name == varName) {
        return;
      }
    }
    final sb = StringBuffer();
    sb.write("Expected to find $varName in top awaiter stack frame, found ");
    if (top.variables.isEmpty) {
      sb.write("no variables\n");
    } else {
      sb.write("these instead:\n");
      for (var variable in top.variables) {
        sb.write("\t${variable.name}\n");
      }
    }
    throw sb.toString();
  };
}

Future resumeIsolate(Isolate isolate) {
  Completer completer = new Completer();
  isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
    var subscription;
    subscription = stream.listen((ServiceEvent event) {
      if (event.kind == ServiceEvent.kResume) {
        subscription.cancel();
        completer.complete();
      }
    });
  });
  isolate.resume();
  return completer.future;
}

Future resumeAndAwaitEvent(Isolate isolate, stream, onEvent) async {
  Completer completer = new Completer();
  var sub;
  sub = await isolate.vm.listenEventStream(stream, (ServiceEvent event) {
    var r = onEvent(event);
    if (r is! Future) {
      r = new Future.value(r);
    }
    r.then((x) => sub.cancel().then((_) {
          completer.complete();
        }));
  });
  await isolate.resume();
  return completer.future;
}

IsolateTest resumeIsolateAndAwaitEvent(stream, onEvent) {
  return (Isolate isolate) async =>
      resumeAndAwaitEvent(isolate, stream, onEvent);
}

Future stepOver(Isolate isolate) async {
  await isolate.stepOver();
  return hasStoppedAtBreakpoint(isolate);
}

Future stepInto(Isolate isolate) async {
  await isolate.stepInto();
  return hasStoppedAtBreakpoint(isolate);
}

Future stepOut(Isolate isolate) async {
  await isolate.stepOut();
  return hasStoppedAtBreakpoint(isolate);
}

Future isolateIsRunning(Isolate isolate) async {
  await isolate.reload();
  expect(isolate.running, true);
}

Future<Class?> getClassFromRootLib(Isolate isolate, String className) async {
  Library rootLib = await isolate.rootLibrary.load() as Library;
  for (Class cls in rootLib.classes) {
    if (cls.name == className) {
      return cls;
    }
  }
  return null;
}

Future<Instance> rootLibraryFieldValue(
    Isolate isolate, String fieldName) async {
  Library rootLib = await isolate.rootLibrary.load() as Library;
  Field field = rootLib.variables.singleWhere((v) => v.name == fieldName);
  await field.load();
  Instance value = field.staticValue as Instance;
  await value.load();
  return value;
}

IsolateTest runStepThroughProgramRecordingStops(List<String> recordStops) {
  return (Isolate isolate) async {
    Completer completer = new Completer();

    await subscribeToStream(isolate.vm, VM.kDebugStream,
        (ServiceEvent event) async {
      if (event.kind == ServiceEvent.kPauseBreakpoint) {
        await isolate.reload();
        // We are paused: Step further.
        Frame frame = isolate.topFrame!;
        recordStops.add(await frame.location!.toUserString());
        if (event.atAsyncSuspension!) {
          isolate.stepOverAsyncSuspension();
        } else {
          isolate.stepOver();
        }
      } else if (event.kind == ServiceEvent.kPauseExit) {
        // We are at the exit: The test is done.
        await cancelStreamSubscription(VM.kDebugStream);
        completer.complete();
      }
    });
    isolate.resume();
    return completer.future;
  };
}

IsolateTest resumeProgramRecordingStops(
    List<String> recordStops, bool includeCaller) {
  return (Isolate isolate) async {
    Completer completer = new Completer();

    await subscribeToStream(isolate.vm, VM.kDebugStream,
        (ServiceEvent event) async {
      if (event.kind == ServiceEvent.kPauseBreakpoint) {
        await isolate.reload();
        // We are paused: Resume after recording.
        ServiceMap stack = await isolate.getStack();
        expect(stack.type, equals('Stack'));
        List frames = stack['frames'];
        expect(frames.length, greaterThanOrEqualTo(2));
        Frame frame = frames[0];
        String brokeAt = await frame.location!.toUserString();
        if (includeCaller) {
          frame = frames[1];
          String calledFrom = await frame.location!.toUserString();
          recordStops.add("$brokeAt ($calledFrom)");
        } else {
          recordStops.add(brokeAt);
        }

        isolate.resume();
      } else if (event.kind == ServiceEvent.kPauseExit) {
        // We are at the exit: The test is done.
        await cancelStreamSubscription(VM.kDebugStream);
        completer.complete();
      }
    });
    print("Resuming!");
    isolate.resume();
    return completer.future;
  };
}

IsolateTest runStepIntoThroughProgramRecordingStops(List<String> recordStops) {
  return (Isolate isolate) async {
    Completer completer = new Completer();

    await subscribeToStream(isolate.vm, VM.kDebugStream,
        (ServiceEvent event) async {
      if (event.kind == ServiceEvent.kPauseBreakpoint) {
        await isolate.reload();
        // We are paused: Step into further.
        Frame frame = isolate.topFrame!;
        recordStops.add(await frame.location!.toUserString());
        isolate.stepInto();
      } else if (event.kind == ServiceEvent.kPauseExit) {
        // We are at the exit: The test is done.
        await cancelStreamSubscription(VM.kDebugStream);
        completer.complete();
      }
    });
    isolate.resume();
    return completer.future;
  };
}

IsolateTest checkRecordedStops(
    List<String> recordStops, List<String> expectedStops,
    {bool removeDuplicates = false,
    bool debugPrint = false,
    String? debugPrintFile,
    int? debugPrintLine}) {
  return (Isolate isolate) async {
    if (debugPrint) {
      for (int i = 0; i < recordStops.length; i++) {
        String line = recordStops[i];
        String output = line;
        int firstColon = line.indexOf(":");
        int lastColon = line.lastIndexOf(":");
        if (debugPrintFile != null &&
            debugPrintLine != null &&
            firstColon > 0 &&
            lastColon > 0) {
          int lineNumber = int.parse(line.substring(firstColon + 1, lastColon));
          int relativeLineNumber = lineNumber - debugPrintLine;
          var columnNumber = line.substring(lastColon + 1);
          var file = line.substring(0, firstColon);
          if (file == debugPrintFile) {
            output = '\$file:\${LINE+$relativeLineNumber}:$columnNumber';
          }
        }
        String comma = i == recordStops.length - 1 ? "" : ",";
        print('"$output"$comma');
      }
    }
    if (removeDuplicates) {
      recordStops = removeAdjacentDuplicates(recordStops);
      expectedStops = removeAdjacentDuplicates(expectedStops);
    }

    // Single stepping may record extra stops.
    // Allow the extra ones as long as the expected ones are recorded.
    int i = 0;
    int j = 0;
    while (i < recordStops.length && j < expectedStops.length) {
      if (recordStops[i] != expectedStops[j]) {
        // Check if recordStops[i] is an extra stop.
        int k = i + 1;
        while (k < recordStops.length && recordStops[k] != expectedStops[j]) {
          k++;
        }
        if (k < recordStops.length) {
          // Allow and ignore extra recorded stops from i to k-1.
          i = k;
        } else {
          // This will report an error.
          expect(recordStops[i], expectedStops[j]);
        }
      }
      i++;
      j++;
    }

    expect(recordStops.length >= expectedStops.length, true,
        reason: "Expects at least ${expectedStops.length} breaks, "
            "got ${recordStops.length}.");
  };
}

List<String> removeAdjacentDuplicates(List<String> fromList) {
  List<String> result = <String>[];
  String? latestLine;
  for (String s in fromList) {
    if (s == latestLine) continue;
    latestLine = s;
    result.add(s);
  }
  return result;
}

Future<void> waitForTargetVMExit(VM vm) async => await vm.onDisconnect;