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**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Creator.
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** accordance with the commercial license agreement provided with the
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** 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
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#include "haskellmanager.h"

#include "ghcmod.h"

#include <utils/hostosinfo.h>

#include <QCoreApplication>
#include <QDir>
#include <QFileInfo>
#include <QSettings>

#include <unordered_map>

static const char kStackExecutableKey[] = "Haskell/StackExecutable";

using namespace Utils;

namespace Haskell {
namespace Internal {

class HaskellManagerPrivate
{
public:
    std::unordered_map<FileName, std::weak_ptr<AsyncGhcMod>> ghcModCache;
    FileName stackExecutable;
};

Q_GLOBAL_STATIC(HaskellManagerPrivate, m_d)
Q_GLOBAL_STATIC(HaskellManager, m_instance)

HaskellManager *HaskellManager::instance()
{
    return m_instance;
}

FileName HaskellManager::findProjectDirectory(const FileName &filePath)
{
    if (filePath.isEmpty())
        return FileName();

    QDir directory(filePath.toFileInfo().isDir() ? filePath.toString()
                                                 : filePath.parentDir().toString());
    directory.setNameFilters({"stack.yaml", "*.cabal"});
    directory.setFilter(QDir::Files | QDir::Readable);
    do {
        if (!directory.entryList().isEmpty())
            return FileName::fromString(directory.path());
    } while (!directory.isRoot() && directory.cdUp());
    return FileName();
}

std::shared_ptr<AsyncGhcMod> HaskellManager::ghcModForFile(const FileName &filePath)
{
    const FileName projectPath = findProjectDirectory(filePath);
    const auto cacheEntry = m_d->ghcModCache.find(projectPath);
    if (cacheEntry != m_d->ghcModCache.cend()) {
        if (cacheEntry->second.expired())
            m_d->ghcModCache.erase(cacheEntry);
        else
            return cacheEntry->second.lock();
    }
    auto ghcmod = std::make_shared<AsyncGhcMod>(projectPath);
    m_d->ghcModCache.insert(std::make_pair(projectPath, ghcmod));
    return ghcmod;
}

FileName defaultStackExecutable()
{
    // stack from brew or the installer script from https://docs.haskellstack.org
    // install to /usr/local/bin.
    if (HostOsInfo::isAnyUnixHost())
        return FileName::fromString("/usr/local/bin/stack");
    return FileName::fromString("stack");
}

FileName HaskellManager::stackExecutable()
{
    return m_d->stackExecutable;
}

void HaskellManager::setStackExecutable(const FileName &filePath)
{
    if (filePath == m_d->stackExecutable)
        return;
    m_d->stackExecutable = filePath;
    emit m_instance->stackExecutableChanged(m_d->stackExecutable);
}

void HaskellManager::readSettings(QSettings *settings)
{
    m_d->stackExecutable = FileName::fromString(
                settings->value(kStackExecutableKey,
                                defaultStackExecutable().toString()).toString());
    emit m_instance->stackExecutableChanged(m_d->stackExecutable);
}

void HaskellManager::writeSettings(QSettings *settings)
{
    if (m_d->stackExecutable == defaultStackExecutable())
        settings->remove(kStackExecutableKey);
    else
        settings->setValue(kStackExecutableKey, m_d->stackExecutable.toString());
}

QString HaskellManager::trLookingUp(const QString &name)
{
    return QCoreApplication::translate("HaskellManager", "Looking up \"%1\"...").arg(name);
}

} // namespace Internal
} // namespace Haskell