#include "frame_policy.h"

#ifdef MT_NATIVE_HAS_LIVE_CLIENT
#include "android_perf.h"
#include "platform/EterBase/FrameRateMode.h"

#include <SDL3/SDL.h>

#include <algorithm>
#include <cmath>
#include <fstream>

namespace mt_host {

// --fps-cap N: the loop starts a frame at most every 1/N s (0 = as fast as vsync allows).
int g_fps_cap = 0;
// --refresh-rate N: the surface's preferred frame rate (Android ANativeWindow_setFrameRate; MainActivity
// also picks the matching display mode). 0 leaves the system default.
int g_refresh_rate = 0;
// --fps-mode N: the frame-rate setting for this run (a test override: the saved setting stays);
// --idle-fps N: the rate after --idle-after S seconds without input (0 = never lower it).
int g_fps_mode = -1;
int g_idle_fps = 30;
double g_idle_after_s = 15.0;

void FrameRatePolicy::load() {
    path_ = settings_path();
    int mode = MtFrameRate::MODE_STANDARD;
    if (std::ifstream in{path_}; in) in >> mode;
    if (g_fps_mode >= 0) mode = g_fps_mode;
    MtFrameRate::Set(mode);
    saved_mode_ = MtFrameRate::Get();
    max_hz_ = int(std::lround(android_perf::max_refresh_rate()));
    if (max_hz_ < 30) max_hz_ = 60;
}

FrameRatePolicy::Decision FrameRatePolicy::decide(double idle_seconds, bool auto_hunt) {
    Decision d;
    d.mode = MtFrameRate::Get();
    if (d.mode != saved_mode_) save(saved_mode_ = d.mode);
    const int active = d.mode == MtFrameRate::MODE_SAVER ? 30
                     : d.mode == MtFrameRate::MODE_HIGH ? max_hz_ : std::min(60, max_hz_);
    d.idle = g_idle_fps > 0 && g_idle_fps < active && idle_seconds >= g_idle_after_s && !auto_hunt;
    d.fps = d.idle ? g_idle_fps : active;
    d.display_hz = d.mode == MtFrameRate::MODE_HIGH && !d.idle ? max_hz_ : std::min(60, max_hz_);
    return d;
}

std::string FrameRatePolicy::settings_path() {
    std::string dir;
    if (char* pref = SDL_GetPrefPath("metin2port", "client")) {
        dir = pref;
        SDL_free(pref);
    }
    return dir + "frame_rate.cfg";
}

void FrameRatePolicy::save(int mode) {
    std::ofstream out{path_, std::ios::trunc};
    out << mode << '\n';
}

} // namespace mt_host
#endif