Stats and achievements

void MyGameClass::Initialize()
{
    // ...
    SteamUserStats()->RequestCurrentStats();
    STEAM_CALLBACK( MyGameClass, OnUserStatsReceived, UserStatsReceived_t );
}

void MyGameClass::OnUserStatsReceived()
{
    // Iterate over stats/achievements, and initialize any necessary game data.
    // Assume that m_achievementIds is an array of "API names" for achievements.
    for (int i = 0; i < m_achievementIds.length; i++)
    {
        const char *achievementName = SteamUserStats()->GetAchievementDisplayAttribute(m_achievementIds[i], "name");
        const char *description = SteamUserStats()->GetAchievementDisplayAttribute(m_achievementIds[i], "desc");
        bool hidden = SteamUserStats()->GetAchievementDisplayAttribute(m_achievementIds[i], "hidden");
        bool isUnlocked;
        SteamUserStats()->GetAchievement(m_achievementIds[i], &isUnlocked);
        // Do any necessary achievement initialization...
    }
}

auto asyncBlock = std::make_unique<XAsyncBlock>();
asyncBlock->context = nullptr;
asyncBlock->callback = [](XAsyncBlock* asyncBlock)
{
    // Take over ownership of the XAsyncBlock*
    std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; 

    XblAchievementsResultHandle resultHandle;
    auto hr = XblAchievementsGetAchievementsForTitleIdResult(asyncBlock, &resultHandle);

    if (SUCCEEDED(hr))
    {
        const XblAchievement* achievements = nullptr;
        size_t achievementsCount = 0;
        hr = XblAchievementsResultGetAchievements(resultHandle, &achievements, &achievementsCount);

        for (size_t i = 0; i < achievements.length; i++)
        {
            auto name = achievement[i].name;
            char description[256];
            char progress[4] = "100";
            if (achievement[i].progressState == XblAchievementProgressState::Achieved)
            {
                strcpy(description, achievement[i].unlockedDescription);
            }
            else
            {
                strcpy(description, achievement[i].lockedDescription);
                strcpy(progress, achievement[i].progression.requirements[0].currentProgressValue);
            }
            // Use this data to initialize achievements...
        }

        // When you're done with the handle, close it. This will free the achievements list 
        // from memory.
        XblAchievementsResultCloseHandle(resultHandle);
        achievements = nullptr; 
        // Instead, you couldn't close the handle and store it.  
        // If you needed to copy the handle, call XblAchievementsResultDuplicateHandle()
    }
};

// Assume m_xblContext is an XBOX services Context handle that has been initialized properly.
uint64_t xuid;
XblContextGetXboxUserId(m_xblContext, &xuid);

HRESULT hr = XblAchievementsGetAchievementsForTitleIdAsync(
    m_xblContext,
    xuid, 
    m_titleId, // Assume this is a uint32_t holding your game's title ID.
    XblAchievementType::Persistent, // achievementType: You probably want to use XblAchievementType::Persistent.
    false, //unlockedOnly: If true, returns only unlocked achievements.
    XblAchievementOrderBy::DefaultOrder, // orderBy: How to order the incoming achievements list. 
    0, // skipItems: The number of achievements to skip. 
    0, // maxItems: Set to 0 to get all achievements/disable pagination.
    asyncBlock.get()
);
if (SUCCEEDED(hr))
{
    // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* since the callback will take over ownership.
    // If the call fails, the std::unique_ptr will keep ownership and delete the XAsyncBlock*
    asyncBlock.release();
}

void MyGame::UpdateAchievement(const char *achievementApiName, const char *statApiName, int diff, int target)
{
    bool isCompleted;
    int value;
    bool result = SteamUserStats()->GetAchievement(achievementApiName, &isCompleted);
    if (!result) {
        // Handle error.
    }

    result = SteamUserStats()->GetStat(statApiName, &value);
    if (!result) {
        // Handle error.
    }

    SteamUserStats()->SetStat(statApiName, value + diff);
    
    if (!isCompleted && value + diff >= target)
    {
             // Unlock the achievement.
        SteamUserStats()->SetAchievement(achievementApiName);
        SteamUserStats()->StoreStats();
    }
}

// At the next checkpoint...
if(!SteamUserStats()->StoreStats()) {
    // Handle error.
}

void MyGame::UpdateAchievement(const std::string& achievementId, int diff, int target)
{
    // Assume this function returns the specified achievement's progress from wherever you're storing it.
    auto previousValue = MyGetAchievementProgress(achievementId);
    // If you're storing progress elsewhere, make sure to update it there, too! Again, we're assuming 
    // that this is a function you've written to update the progress value wherever it's stored.
    MySetAchievementProgress(previousValue + diff);
    // Calculate the percent of the target that the user has reached after adding the value of diff.
    uint32_t percentComplete = (previousValue + diff) / target;

    auto async = std::make_unique<XAsyncBlock>();
    async->context = nullptr;
    async->callback = [](XAsyncBlock *async)
    {
        // Take over ownership of the XAsyncBlock*
        std::unique_ptr<XAsyncBlock> asyncBlockPtr{ async }; 

        HRESULT result = XAsyncGetStatus(async, true);

        if (SUCCEEDED(result))
        {
            // Success!
        }
        else
        {
            if (result == HTTP_E_STATUS_NOT_MODIFIED)
            {
                // The achievement was already completed or it was previously
                // set to a higher value, so it's unchanged.
            }
            else
            {
                // Handle error.
            }
        }
    };

    // Assume m_xblContext is an XBOX services Context handle that has been initialized properly.
    uint64_t xuid;
    XblContextGetXboxUserId(m_xblContext, &xuid);
    HRESULT hr = XblAchievementsUpdateAchievementAsync(
        m_xblContext,
        xuid,
        achievementId.c_str(),
        percentComplete,
        async
    );

    if (SUCCEEDED(hr))
    {
        // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* since the callback will take over ownership.
        // If the call fails, the std::unique_ptr will keep ownership and delete the XAsyncBlock*
        asyncBlock.release();
    }
}