/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qbs.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
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** $QT_END_LICENSE$
**
****************************************************************************/
#include "benchmarker.h"

#include "exception.h"
#include "runsupport.h"
#include "valgrindrunner.h"

#include <QtConcurrent/qtconcurrentrun.h>
#include <QtCore/QCoreApplication>

#include <iostream>
#include <utility>

namespace qbsBenchmarker {

Benchmarker::Benchmarker(Activities activities, QString oldCommit, QString newCommit,
                         QString testProject, QString qbsRepo)
    : m_activities(activities)
    , m_oldCommit(std::move(oldCommit))
    , m_newCommit(std::move(newCommit))
    , m_testProject(std::move(testProject))
    , m_qbsRepo(std::move(qbsRepo))
{
}

Benchmarker::~Benchmarker()
{
    if (!m_commitToRestore.isEmpty()) {
        try {
            runProcess(QStringList() << "git" << "checkout" << m_commitToRestore, m_qbsRepo);
        } catch (const Exception &e) {
            qDebug("Failed to restore original commit %s: %s", qPrintable(m_commitToRestore),
                   qPrintable(e.description()));
        }
    }
}

void Benchmarker::benchmark()
{
    rememberCurrentRepoState();
    runProcess(QStringList() << "git" << "checkout" << m_oldCommit, m_qbsRepo);
    const QString oldQbsBuildDir = m_baseOutputDir.path() + "/qbs-build." + m_oldCommit;
    std::cout << "Building from old repo state..." << std::endl;
    buildQbs(oldQbsBuildDir);
    runProcess(QStringList() << "git" << "checkout" << m_newCommit, m_qbsRepo);
    const QString newQbsBuildDir = m_baseOutputDir.path() + "/qbs-build." + m_newCommit;
    std::cout << "Building from new repo state..." << std::endl;
    buildQbs(newQbsBuildDir);
    std::cout << "Now running valgrind. This can take a while." << std::endl;

    ValgrindRunner oldDataRetriever(m_activities, m_testProject, oldQbsBuildDir,
                                    m_baseOutputDir.path() + "/benchmark-data." + m_oldCommit);
    ValgrindRunner newDataRetriever(m_activities, m_testProject, newQbsBuildDir,
                                    m_baseOutputDir.path() + "/benchmark-data." + m_newCommit);
    QFuture<void> oldFuture = QtConcurrent::run([&oldDataRetriever]{ oldDataRetriever.run(); });
    QFuture<void> newFuture = QtConcurrent::run([&newDataRetriever]{ newDataRetriever.run(); });
    oldFuture.waitForFinished();
    const auto oldValgrindResults = oldDataRetriever.results();
    for (const ValgrindResult &valgrindResult : oldValgrindResults) {
        BenchmarkResult &benchmarkResult = m_results[valgrindResult.activity];
        benchmarkResult.oldInstructionCount = valgrindResult.instructionCount;
        benchmarkResult.oldPeakMemoryUsage = valgrindResult.peakMemoryUsage;
    }
    newFuture.waitForFinished();
    const auto newValgrindResults = newDataRetriever.results();
    for (const ValgrindResult &valgrindResult : newValgrindResults) {
        BenchmarkResult &benchmarkResult = m_results[valgrindResult.activity];
        benchmarkResult.newInstructionCount = valgrindResult.instructionCount;
        benchmarkResult.newPeakMemoryUsage = valgrindResult.peakMemoryUsage;
    }
    std::cout << "Done!" << std::endl;
}

void Benchmarker::rememberCurrentRepoState()
{
    QByteArray commit;
    int exitCode = 0;
    try {
        runProcess(QStringList() << "git" << "symbolic-ref" << "--short" << "HEAD", m_qbsRepo,
                   &commit, &exitCode);
    } catch (const Exception &) {
        if (exitCode == 0) {
            // runProcess did not throw because of the exit code.
            throw;
        }
        // Fallback, in case git cannot retrieve a nice symbolic name.
        runProcess(QStringList() << "git" << "describe" << "HEAD", m_qbsRepo, &commit);
    }
    m_commitToRestore = QString::fromLatin1(commit);
}

void Benchmarker::buildQbs(const QString &buildDir) const
{
    if (!QDir::root().mkpath(buildDir))
        throw Exception(QStringLiteral("Failed to create directory '%1'.").arg(buildDir));
    runProcess(QStringList() << QCoreApplication::applicationDirPath() + "/qbs"
               << "resolve"
               << "config:benchmarker"
               << "qbs.buildVariant:profiling"
               << "qbs.installPrefix:''"
               << "-f" << m_qbsRepo + "/qbs.qbs", buildDir);
    runProcess(QStringList() << QCoreApplication::applicationDirPath() + "/qbs"
               << "build"
               << "config:benchmarker", buildDir);
}

} // namespace qbsBenchmarker
