#include "core/application.hpp"
#include "core/logger.hpp"
#include <exception>
#include <csignal>
#include <cstdlib>
#include <cctype>
#include <string>
#include <SDL2/SDL.h>
#ifdef __APPLE__
#include <mach-o/dyld.h>
#include <libgen.h>
#include <unistd.h>
#endif
#ifdef __linux__
#include <X11/Xlib.h>
#include <execinfo.h>
#include <unistd.h>
#include <cstring>

// Keep a persistent X11 connection for emergency mouse release in signal handlers.
// XOpenDisplay inside a signal handler is unreliable, so we open it once at startup.
static Display* g_emergencyDisplay = nullptr;

static void releaseMouseGrab() {
    if (g_emergencyDisplay) {
        XUngrabPointer(g_emergencyDisplay, CurrentTime);
        XUngrabKeyboard(g_emergencyDisplay, CurrentTime);
        XFlush(g_emergencyDisplay);
    }
}
#else
static void releaseMouseGrab() {}
#endif

#ifdef __linux__
static void crashHandlerSigaction(int sig, siginfo_t* info, void* /*ucontext*/) {
    releaseMouseGrab();
    void* frames[64];
    int n = backtrace(frames, 64);
    const char* sigName = (sig == SIGSEGV) ? "SIGSEGV" :
                          (sig == SIGABRT) ? "SIGABRT" :
                          (sig == SIGFPE)  ? "SIGFPE"  : "UNKNOWN";
    void* faultAddr = info ? info->si_addr : nullptr;
    fprintf(stderr, "\n=== CRASH: signal %s (%d) faultAddr=%p ===\n",
            sigName, sig, faultAddr);
    backtrace_symbols_fd(frames, n, STDERR_FILENO);
    FILE* f = fopen("/tmp/wowee_debug.log", "a");
    if (f) {
        fprintf(f, "\n=== CRASH: signal %s (%d) faultAddr=%p ===\n",
                sigName, sig, faultAddr);
        fflush(f);
        backtrace_symbols_fd(frames, n, fileno(f));
        fclose(f);
    }
    // Re-raise with default handler
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = SIG_DFL;
    sigaction(sig, &sa, nullptr);
    raise(sig);
}
#else
static void crashHandler(int sig) {
    releaseMouseGrab();
    std::signal(sig, SIG_DFL);
    std::raise(sig);
}
#endif

static wowee::core::LogLevel readLogLevelFromEnv() {
    const char* raw = std::getenv("WOWEE_LOG_LEVEL");
    if (!raw || !*raw) return wowee::core::LogLevel::WARNING;
    std::string level(raw);
    for (char& c : level) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
    if (level == "debug") return wowee::core::LogLevel::DEBUG;
    if (level == "info") return wowee::core::LogLevel::INFO;
    if (level == "warn" || level == "warning") return wowee::core::LogLevel::WARNING;
    if (level == "error") return wowee::core::kLogLevelError;
    if (level == "fatal") return wowee::core::LogLevel::FATAL;
    return wowee::core::LogLevel::WARNING;
}

int main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[]) {
#ifdef __linux__
    g_emergencyDisplay = XOpenDisplay(nullptr);
    // Use sigaction for SIGSEGV/SIGABRT/SIGFPE to get si_addr (faulting address)
    {
        struct sigaction sa;
        memset(&sa, 0, sizeof(sa));
        sa.sa_sigaction = crashHandlerSigaction;
        sa.sa_flags = SA_SIGINFO;
        sigaction(SIGSEGV, &sa, nullptr);
        sigaction(SIGABRT, &sa, nullptr);
        sigaction(SIGFPE,  &sa, nullptr);
    }
    std::signal(SIGTERM, [](int) { std::_Exit(1); });
    std::signal(SIGINT,  [](int) { std::_Exit(1); });
#else
    std::signal(SIGSEGV, crashHandler);
    std::signal(SIGABRT, crashHandler);
    std::signal(SIGFPE,  crashHandler);
    std::signal(SIGTERM, crashHandler);
    std::signal(SIGINT,  crashHandler);
#endif
    // Change working directory to the executable's directory so relative asset
    // paths (assets/shaders/, Data/, etc.) resolve correctly from any launch location.
#ifdef __APPLE__
    {
        uint32_t bufSize = 0;
        _NSGetExecutablePath(nullptr, &bufSize);
        std::string exePath(bufSize, '\0');
        _NSGetExecutablePath(exePath.data(), &bufSize);
        chdir(dirname(exePath.data()));
    }
#elif defined(__linux__)
    {
        char buf[4096];
        ssize_t len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
        if (len > 0) { buf[len] = '\0'; chdir(dirname(buf)); }
    }
#endif

    try {
        wowee::core::Logger::getInstance().setLogLevel(readLogLevelFromEnv());
        LOG_INFO("=== Wowee Native Client ===");
        LOG_INFO("Starting application...");

        wowee::core::Application app;

        if (!app.initialize()) {
            LOG_FATAL("Failed to initialize application");
            return 1;
        }

        app.run();
        app.shutdown();

        LOG_INFO("Application exited successfully");
#ifdef __linux__
        if (g_emergencyDisplay) { XCloseDisplay(g_emergencyDisplay); g_emergencyDisplay = nullptr; }
#endif
        return 0;
    }
    catch (const std::exception& e) {
        releaseMouseGrab();
        LOG_FATAL("Unhandled exception: ", e.what());
        return 1;
    }
    catch (...) {
        releaseMouseGrab();
        LOG_FATAL("Unknown exception occurred");
        return 1;
    }
}