UpdateChecker.cpp

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/*
    MetaImGUI
    Copyright (C) 2026  A P Nicholson
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
 
#include "UpdateChecker.h"
 
#include "Logger.h"
#include "version.h"
 
#include <nlohmann/json.hpp>
 
#include <algorithm>
#include <cctype>
#include <sstream>
 
// HTTP requests using libcurl (cross-platform)
#include <curl/curl.h>
 
namespace MetaImGUI {
 
UpdateChecker::UpdateChecker(std::string repoOwner, std::string repoName)
    : m_repoOwner(std::move(repoOwner)), m_repoName(std::move(repoName)), m_checking(false) {}
 
UpdateChecker::~UpdateChecker() {
    // C++20: std::jthread automatically joins on destruction
    Cancel();
}
 
void UpdateChecker::CheckForUpdatesAsync(std::function<void(const UpdateInfo&)> callback) {
    const std::lock_guard<std::mutex> lock(m_threadMutex);
 
    if (m_checking) {
        LOG_INFO("Update Checker: Check already in progress, skipping");
        return; // Already checking
    }
 
    m_checking = true;
 
    // C++20: std::jthread with stop_token for clean cancellation
    m_stopSource = std::stop_source();
    m_checkThread = std::jthread([this, callback](const std::stop_token& stopToken) {
        const UpdateInfo info = CheckForUpdatesImpl(stopToken);
 
        m_checking = false;
 
        // Only invoke callback if not cancelled
        if (!stopToken.stop_requested() && callback) {
            try {
                callback(info);
            } catch (const std::exception& e) {
                LOG_ERROR("Update Checker: Callback threw exception: {}", e.what());
            } catch (...) {
                LOG_ERROR("Update Checker: Callback threw unknown exception");
            }
        }
    });
    // C++20: jthread automatically joins on destruction, no detach() needed
}
 
UpdateInfo UpdateChecker::CheckForUpdates() {
    m_checking = true;
    // For synchronous calls, use a default stop_token that never stops
    UpdateInfo info = CheckForUpdatesImpl(std::stop_token{});
    m_checking = false;
    return info;
}
 
void UpdateChecker::Cancel() {
    const std::lock_guard<std::mutex> lock(m_threadMutex);
 
    // C++20: Request stop using stop_source
    m_stopSource.request_stop();
 
    // jthread automatically joins, so we just need to request stop
    LOG_INFO("Update Checker: Cancellation requested");
}
 
bool UpdateChecker::IsChecking() const {
    return m_checking;
}
 
UpdateInfo UpdateChecker::CheckForUpdatesImpl(const std::stop_token& stopToken) {
    // C++20: Using designated initializers for clear initialization
    UpdateInfo info{.updateAvailable = false,
                    .latestVersion = "",
                    .currentVersion = Version::VERSION,
                    .releaseUrl = "",
                    .releaseNotes = "",
                    .downloadUrl = ""};
 
    try {
        const std::string jsonResponse = FetchLatestReleaseInfo();
        if (stopToken.stop_requested()) {
            LOG_INFO("Update Checker: Check cancelled by user");
            return info;
        }
 
        if (jsonResponse.empty()) {
            LOG_ERROR("Update Checker: Empty response from server");
            return info;
        }
 
        info = ParseReleaseInfo(jsonResponse);
        info.currentVersion = Version::VERSION;
 
        // Compare versions
        if (!info.latestVersion.empty()) {
            const int cmp = CompareVersions(info.currentVersion, info.latestVersion);
            info.updateAvailable = (cmp < 0);
 
            if (info.updateAvailable) {
                LOG_INFO("Update Checker: Update available - {} -> {}", info.currentVersion, info.latestVersion);
            } else {
                LOG_INFO("Update Checker: No update available (current: {})", info.currentVersion);
            }
        } else {
            LOG_ERROR("Update Checker: Could not parse latest version from response");
        }
    } catch (const std::bad_alloc& e) {
        LOG_ERROR("Update Checker: Memory allocation failed: {}", e.what());
        info.updateAvailable = false;
    } catch (const std::exception& e) {
        LOG_ERROR("Update Checker: Check failed: {}", e.what());
        info.updateAvailable = false;
    } catch (...) {
        LOG_ERROR("Update Checker: Unknown error during update check");
        info.updateAvailable = false;
    }
 
    return info;
}
 
// Unified cross-platform implementation using libcurl
 
namespace {
size_t WriteCallback(void* contents, size_t size, size_t nmemb, void* userp) {
    static_cast<std::string*>(userp)->append(static_cast<char*>(contents), size * nmemb);
    return size * nmemb;
}
} // namespace
 
std::string UpdateChecker::FetchLatestReleaseInfo() {
    std::string result;
 
    // RAII-wrap CURL handle to prevent leaks on exceptions
    const std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> curl(curl_easy_init(), curl_easy_cleanup);
    if (!curl) {
        return result;
    }
 
    const std::string url = "https://api.github.com/repos/" + m_repoOwner + "/" + m_repoName + "/releases/latest";
 
    LOG_INFO("Update Checker: Requesting URL: {}", url);
 
    curl_easy_setopt(curl.get(), CURLOPT_URL, url.c_str());
    curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteCallback);
    curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &result);
    curl_easy_setopt(curl.get(), CURLOPT_USERAGENT, "UpdateChecker/1.0");
    curl_easy_setopt(curl.get(), CURLOPT_FOLLOWLOCATION, 1L);
    curl_easy_setopt(curl.get(), CURLOPT_TIMEOUT, 10L);
    curl_easy_setopt(curl.get(), CURLOPT_SSL_VERIFYPEER, 1L);
    curl_easy_setopt(curl.get(), CURLOPT_SSL_VERIFYHOST, 2L);
 
    const CURLcode res = curl_easy_perform(curl.get());
 
    if (res != CURLE_OK) {
        LOG_ERROR("Update Checker: Request failed: {}", curl_easy_strerror(res));
        result.clear();
    }
 
    LOG_INFO("Update Checker: Response received ({} bytes)", result.size());
 
    return result;
}
 
UpdateInfo UpdateChecker::ParseReleaseInfo(const std::string& jsonResponse) {
    UpdateInfo info;
 
    if (jsonResponse.empty()) {
        LOG_ERROR("Update Checker: Empty JSON response");
        return info;
    }
 
    try {
        // Parse JSON using nlohmann/json library
        auto j = nlohmann::json::parse(jsonResponse);
 
        // Extract tag_name
        if (j.contains("tag_name") && j["tag_name"].is_string()) {
            std::string tag = j["tag_name"].get<std::string>();
            // Remove 'v' prefix if present
            info.latestVersion = (!tag.empty() && tag[0] == 'v') ? tag.substr(1) : tag;
            LOG_INFO("Update Checker: Parsed version: {}", info.latestVersion);
        } else {
            LOG_ERROR("Update Checker: No tag_name in response");
        }
 
        // Extract html_url
        if (j.contains("html_url") && j["html_url"].is_string()) {
            info.releaseUrl = j["html_url"].get<std::string>();
            LOG_INFO("Update Checker: Release URL: {}", info.releaseUrl);
        }
 
        // Extract body (release notes)
        if (j.contains("body") && j["body"].is_string()) {
            info.releaseNotes = j["body"].get<std::string>();
            LOG_INFO("Update Checker: Release notes: {} chars", info.releaseNotes.length());
        }
 
        // Extract download_url (if available)
        if (j.contains("assets") && j["assets"].is_array() && !j["assets"].empty()) {
            auto& firstAsset = j["assets"][0];
            if (firstAsset.contains("browser_download_url") && firstAsset["browser_download_url"].is_string()) {
                info.downloadUrl = firstAsset["browser_download_url"].get<std::string>();
            }
        }
 
    } catch (const nlohmann::json::parse_error& e) {
        LOG_ERROR("Update Checker: JSON parse error: {} at byte {}", e.what(), e.byte);
    } catch (const nlohmann::json::type_error& e) {
        LOG_ERROR("Update Checker: JSON type error: {}", e.what());
    } catch (const std::exception& e) {
        LOG_ERROR("Update Checker: Unexpected error parsing JSON: {}", e.what());
    }
 
    return info;
}
 
int UpdateChecker::CompareVersions(const std::string& v1, const std::string& v2) {
    auto parseVersion = [](std::string version) {
        // Remove leading 'v' or 'V' if present
        if (!version.empty() && (version[0] == 'v' || version[0] == 'V')) {
            version = version.substr(1);
        }
 
        std::vector<int> parts;
        std::stringstream ss(version);
        std::string part;
 
        while (std::getline(ss, part, '.')) {
            // Extract numeric part only
            std::string numStr;
            for (const char c : part) {
                if (std::isdigit(c) != 0) {
                    numStr += c;
                } else {
                    break;
                }
            }
            if (!numStr.empty()) {
                parts.push_back(std::stoi(numStr));
            }
        }
 
        // Ensure at least 3 parts (major.minor.patch)
        while (parts.size() < 3) {
            parts.push_back(0);
        }
 
        return parts;
    };
 
    auto parts1 = parseVersion(v1);
    auto parts2 = parseVersion(v2);
 
    for (size_t i = 0; i < (std::min)(parts1.size(), parts2.size()); ++i) {
        if (parts1[i] < parts2[i]) {
            return -1;
        }
        if (parts1[i] > parts2[i]) {
            return 1;
        }
    }
 
    return 0;
}
 
} // namespace MetaImGUI