// Copyright (c) 2012, 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.

import 'measurement.dart';
import 'score_emitter.dart';

const int minimumMeasureDurationMillis = 2000;

class BenchmarkBase {
  final String name;
  final ScoreEmitter emitter;

  const BenchmarkBase(this.name, {this.emitter = const PrintEmitter()});

  /// The benchmark code.
  ///
  /// This function is not used, if both [warmup] and [exercise] are
  /// overwritten.
  void run() {}

  /// Runs a short version of the benchmark. By default invokes [run] once.
  void warmup() {
    run();
  }

  /// Exercises the benchmark. By default invokes [run] 10 times.
  void exercise() {
    for (var i = 0; i < 10; i++) {
      run();
    }
  }

  /// Not measured setup code executed prior to the benchmark runs.
  void setup() {}

  /// Not measured teardown code executed after the benchmark runs.
  void teardown() {}

  /// Measures the score for this benchmark by executing it enough times
  /// to reach [minimumMillis].

  /// Measures the score for this benchmark by executing it repeatedly until
  /// time minimum has been reached.
  static double measureFor(void Function() f, int minimumMillis) =>
      measureForImpl(f, minimumMillis).score;

  /// Measures the score for the benchmark and returns it.
  double measure() {
    setup();
    // Warmup for at least 100ms. Discard result.
    measureForImpl(warmup, 100);
    // Run the benchmark for at least 2000ms.
    var result = measureForImpl(exercise, minimumMeasureDurationMillis);
    teardown();
    return result.score;
  }

  void report() {
    emitter.emit(name, measure());
  }
}