1 files changed, 135 insertions, 0 deletions
diff --git a/src/core/launch_timestamp_cache.cpp b/src/core/launch_timestamp_cache.cpp
new file mode 100644
index 0000000000..5a154a5c2f
--- /dev/null
+++ b/src/core/launch_timestamp_cache.cpp
@@ -0,0 +1,135 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "core/launch_timestamp_cache.h"
+
+#include <filesystem>
+#include <fstream>
+#include <mutex>
+#include <sstream>
+#include <string>
+#include <unordered_map>
+
+#include <fmt/format.h>
+#include <nlohmann/json.hpp>
+
+#include "common/fs/fs.h"
+#include "common/fs/file.h"
+#include "common/fs/path_util.h"
+#include "common/logging/log.h"
+
+namespace Core::LaunchTimestampCache {
+namespace {
+
+using CacheMap = std::unordered_map<u64, s64>;
+
+std::mutex mutex;
+CacheMap cache;
+bool loaded = false;
+
+std::filesystem::path GetCachePath() {
+    return Common::FS::GetEdenPath(Common::FS::EdenPath::CacheDir) / "launched.json";
+}
+
+std::optional<std::string> ReadFileToString(const std::filesystem::path& path) {
+    const std::ifstream file{path, std::ios::in | std::ios::binary};
+    if (!file) {
+        return std::nullopt;
+    }
+    std::ostringstream ss;
+    ss << file.rdbuf();
+    return ss.str();
+}
+
+bool WriteStringToFile(const std::filesystem::path& path, const std::string& data) {
+    if (!Common::FS::CreateParentDirs(path)) {
+        return false;
+    }
+    std::ofstream file{path, std::ios::out | std::ios::binary | std::ios::trunc};
+    if (!file) {
+        return false;
+    }
+    file.write(data.data(), static_cast<std::streamsize>(data.size()));
+    return static_cast<bool>(file);
+}
+
+void Load() {
+    if (loaded) {
+        return;
+    }
+
+    loaded = true;
+
+    const auto path = GetCachePath();
+    if (!std::filesystem::exists(path)) {
+        return;
+    }
+
+    const auto data = ReadFileToString(path);
+    if (!data) {
+        LOG_WARNING(Core, "Failed to read launch timestamp cache: {}",
+                    Common::FS::PathToUTF8String(path));
+        return;
+    }
+
+    try {
+        const auto json = nlohmann::json::parse(data->data(), data->data() + data->size());
+        if (!json.is_object()) {
+            return;
+        }
+        for (auto it = json.begin(); it != json.end(); ++it) {
+            const auto key_str = it.key();
+            const auto value = it.value();
+            u64 key{};
+            try {
+                key = std::stoull(key_str, nullptr, 16);
+            } catch (...) {
+                continue;
+            }
+            if (value.is_number_integer()) {
+                cache[key] = value.get<s64>();
+            }
+        }
+    } catch (const std::exception& e) {
+        LOG_WARNING(Core, "Failed to parse launch timestamp cache");
+    }
+}
+
+void Save() {
+    nlohmann::json json = nlohmann::json::object();
+    for (const auto& [key, value] : cache) {
+        json[fmt::format("{:016X}", key)] = value;
+    }
+
+    const auto path = GetCachePath();
+    if (!WriteStringToFile(path, json.dump(4))) {
+        LOG_WARNING(Core, "Failed to write launch timestamp cache: {}",
+                    Common::FS::PathToUTF8String(path));
+    }
+}
+
+s64 NowSeconds() {
+    return std::time(nullptr);
+}
+
+} // namespace
+
+void SaveLaunchTimestamp(u64 title_id) {
+    std::scoped_lock lk{mutex};
+    Load();
+    cache[title_id] = NowSeconds();
+    Save();
+}
+
+s64 GetLaunchTimestamp(u64 title_id) {
+    std::scoped_lock lk{mutex};
+    Load();
+    const auto it = cache.find(title_id);
+    if (it != cache.end()) {
+        return it->second;
+    }
+    // we need a timestamp, i decided on 01/01/2026 00:00
+    return 1767225600;
+}
+
+} // namespace Core::LaunchTimestampCache