#include "profiler.h"
#include "../util/util.h"
#include <atomic>
#include <mutex>
#include <unordered_map>
#include <vector>
#include <algorithm>
#include <chrono>
#include <thread>

namespace {

std::atomic<bool> g_profilingEnabled{false};
std::mutex g_histMutex;
std::unordered_map<uint64_t, uint64_t> g_hist;
std::atomic<uint64_t> g_totalSamples{0};
std::atomic<bool> g_dumpThreadStarted{false};

} // namespace

void EnableProfiling() { g_profilingEnabled.store(true, std::memory_order_relaxed); }
bool ProfilingEnabled() { return g_profilingEnabled.load(std::memory_order_relaxed); }

void ProfileBlockHookCb(uc_engine*, uint64_t address, uint32_t, void*) {
    // thread_local, not a shared "last sample" - each real host thread has
    // its own uc_engine (see guest_engine.h's "Multithreading model") and
    // fires this independently; gating per-thread avoids one busy thread's
    // sampling starving another's.
    static thread_local std::chrono::steady_clock::time_point lastSample{};
    auto now = std::chrono::steady_clock::now();
    if (now - lastSample < std::chrono::milliseconds(2)) return;
    lastSample = now;

    std::lock_guard<std::mutex> lock(g_histMutex);
    g_hist[address]++;
    g_totalSamples.fetch_add(1, std::memory_order_relaxed);
}

void StartProfileDumpThread() {
    bool expected = false;
    if (!g_dumpThreadStarted.compare_exchange_strong(expected, true)) return; // already running

    std::thread([]() {
        while (true) {
            std::this_thread::sleep_for(std::chrono::seconds(3));

            std::vector<std::pair<uint64_t, uint64_t>> top;
            {
                std::lock_guard<std::mutex> lock(g_histMutex);
                top.assign(g_hist.begin(), g_hist.end());
            }
            if (top.empty()) continue;

            std::sort(top.begin(), top.end(),
                      [](const auto& a, const auto& b) { return a.second > b.second; });
            uint64_t total = g_totalSamples.load(std::memory_order_relaxed);

            Log("PROFILE: %llu total samples across %zu distinct block addresses - top hot PCs:",
                (unsigned long long)total, top.size());
            for (size_t i = 0; i < top.size() && i < 15; i++) {
                Log("PROFILE:   0x%llx - %llu samples (%.1f%%)",
                    (unsigned long long)top[i].first, (unsigned long long)top[i].second,
                    total ? 100.0 * (double)top[i].second / (double)total : 0.0);
            }
        }
    }).detach();
}