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** Copyright (C) 2016 The Qt Company Ltd.
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** 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
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#include "refactoringserver.h"

#include "symbolfinder.h"
#include "clangquery.h"

#include <refactoringclientinterface.h>
#include <requestsourcelocationforrenamingmessage.h>
#include <requestsourcerangesanddiagnosticsforquerymessage.h>
#include <sourcelocationsforrenamingmessage.h>
#include <sourcerangesanddiagnosticsforquerymessage.h>

#include <QCoreApplication>

#include <algorithm>
#include <chrono>
#include <future>
#include <atomic>

namespace ClangBackEnd {

RefactoringServer::RefactoringServer()
{
    pollEventLoop = [] () { QCoreApplication::processEvents(); };
}

void RefactoringServer::end()
{
    QCoreApplication::exit();
}

void RefactoringServer::requestSourceLocationsForRenamingMessage(RequestSourceLocationsForRenamingMessage &&message)
{
    SymbolFinder symbolFinder(message.line(), message.column());

    symbolFinder.addFile(message.filePath().directory(),
                         message.filePath().name(),
                         message.unsavedContent(),
                         message.commandLine());

    symbolFinder.findSymbol();

    client()->sourceLocationsForRenamingMessage({symbolFinder.takeSymbolName(),
                                                 symbolFinder.takeSourceLocations(),
                                                 message.textDocumentRevision()});
}

void RefactoringServer::requestSourceRangesAndDiagnosticsForQueryMessage(
        RequestSourceRangesAndDiagnosticsForQueryMessage &&message)
{
    gatherSourceRangesAndDiagnosticsForQueryMessage(message.takeFileContainers(), message.takeQuery());
}

void RefactoringServer::cancel()
{
    cancelWork = true;
}

bool RefactoringServer::isCancelingJobs() const
{
    return cancelWork;
}

void RefactoringServer::supersedePollEventLoop(std::function<void ()> &&pollEventLoop)
{
    this->pollEventLoop = std::move(pollEventLoop);
}

namespace {

SourceRangesAndDiagnosticsForQueryMessage createSourceRangesAndDiagnosticsForQueryMessage(
        V2::FileContainer &&fileContainer,
        Utils::SmallString &&query,
        const std::atomic_bool &cancelWork) {
    ClangQuery clangQuery(std::move(query));

    if (!cancelWork) {
        clangQuery.addFile(fileContainer.filePath().directory(),
                           fileContainer.filePath().name(),
                           fileContainer.takeUnsavedFileContent(),
                           fileContainer.takeCommandLineArguments());

        clangQuery.findLocations();
    }

    return {clangQuery.takeSourceRanges(), clangQuery.takeDiagnosticContainers()};
}


}

void RefactoringServer::gatherSourceRangesAndDiagnosticsForQueryMessage(
        std::vector<V2::FileContainer> &&fileContainers,
        Utils::SmallString &&query)
{
    std::vector<Future> futures;

    std::size_t freeProcessors = std::thread::hardware_concurrency();

    while (!fileContainers.empty() || !futures.empty()) {
        --freeProcessors;

        if (!fileContainers.empty()) {
            Future &&future = std::async(std::launch::async,
                                         createSourceRangesAndDiagnosticsForQueryMessage,
                                         std::move(fileContainers.back()),
                                         query.clone(), std::ref(cancelWork));
            fileContainers.pop_back();

            futures.emplace_back(std::move(future));
        }

        if (freeProcessors == 0 || fileContainers.empty())
            freeProcessors += waitForNewSourceRangesAndDiagnosticsForQueryMessage(futures);
    }
}

std::size_t RefactoringServer::waitForNewSourceRangesAndDiagnosticsForQueryMessage(std::vector<Future> &futures)
{
    while (true) {
        pollEventLoop();

        std::vector<Future> readyFutures;
        readyFutures.reserve(futures.size());

        auto beginReady = std::partition(futures.begin(),
                                         futures.end(),
                                         [] (const Future &future) {
            return future.wait_for(std::chrono::duration<int>::zero()) != std::future_status::ready;
        });

        std::move(beginReady, futures.end(), std::back_inserter(readyFutures));
        futures.erase(beginReady, futures.end());

        for (Future &readyFuture : readyFutures)
            client()->sourceRangesAndDiagnosticsForQueryMessage(std::move(readyFuture.get()));

        if (readyFutures.empty())
            std::this_thread::sleep_for(std::chrono::milliseconds(20));
        else
            return readyFutures.size();
    }
}

} // namespace ClangBackEnd