#include "ppsspp_config.h"

#include <cstdio>
#include <cstdint>

#include "Common/TimeUtil.h"

#ifdef HAVE_LIBNX
#include <switch.h>
#endif // HAVE_LIBNX

#ifdef __EMSCRIPTEN__
#include <emscripten/emscripten.h>
#endif // __EMSCRIPTEN__

#ifdef _WIN32
#include "CommonWindows.h"
#include <mmsystem.h>
#include <sys/timeb.h>
#else
#include <sys/time.h>
#include <unistd.h>
#endif

// for _mm_pause
#if PPSSPP_ARCH(X86) || PPSSPP_ARCH(AMD64)
#include <immintrin.h>
#endif

#include <ctime>

// TODO: https://github.com/floooh/sokol/blob/9a6237fcdf213e6da48e4f9201f144bcb2dcb46f/sokol_time.h#L229-L248

static const double micros = 1000000.0;
static const double nanos = 1000000000.0;

#if PPSSPP_PLATFORM(WINDOWS)

static LARGE_INTEGER frequency;
static double frequencyMult;
static LARGE_INTEGER startTime;

double time_now_d() {
	if (frequency.QuadPart == 0) {
		QueryPerformanceFrequency(&frequency);
		QueryPerformanceCounter(&startTime);
		frequencyMult = 1.0 / static_cast<double>(frequency.QuadPart);
	}
	LARGE_INTEGER time;
	QueryPerformanceCounter(&time);
	double elapsed = static_cast<double>(time.QuadPart - startTime.QuadPart);
	return elapsed * frequencyMult;
}

// Fake, but usable in a pinch. Don't, though.
uint64_t time_now_raw() {
	return (uint64_t)(time_now_d() * nanos);
}

double from_time_raw(uint64_t raw_time) {
	if (raw_time == 0) {
		return 0.0; // invalid time
	}
	return (double)raw_time * (1.0 / nanos);
}

double from_time_raw_relative(uint64_t raw_time) {
	return from_time_raw(raw_time);
}

double time_now_unix_utc() {
	const int64_t UNIX_TIME_START = 0x019DB1DED53E8000; //January 1, 1970 (start of Unix epoch) in "ticks"
	const double TICKS_PER_SECOND = 10000000; //a tick is 100ns

	FILETIME ft;
	GetSystemTimeAsFileTime(&ft); //returns ticks in UTC
	// Copy the low and high parts of FILETIME into a LARGE_INTEGER
	LARGE_INTEGER li;
	li.LowPart = ft.dwLowDateTime;
	li.HighPart = ft.dwHighDateTime;
	//Convert ticks since 1/1/1970 into seconds
	return (double)(li.QuadPart - UNIX_TIME_START) / TICKS_PER_SECOND;
}

void yield() {
	YieldProcessor();
}

#elif PPSSPP_PLATFORM(ANDROID) || PPSSPP_PLATFORM(LINUX) || PPSSPP_PLATFORM(MAC) || PPSSPP_PLATFORM(IOS)

// The only intended use is to match the timings in VK_GOOGLE_display_timing
uint64_t time_now_raw() {
	struct timespec tp;
	clock_gettime(CLOCK_MONOTONIC, &tp);
	return tp.tv_sec * 1000000000ULL + tp.tv_nsec;
}

static uint64_t g_startTime;

double from_time_raw(uint64_t raw_time) {
	return (double)(raw_time - g_startTime) * (1.0 / nanos);
}

double time_now_d() {
	uint64_t raw_time = time_now_raw();
	if (g_startTime == 0) {
		g_startTime = raw_time;
	}
	return from_time_raw(raw_time);
}

double from_time_raw_relative(uint64_t raw_time) {
	return (double)raw_time * (1.0 / nanos);
}

double time_now_unix_utc() {
	struct timespec tp;
	clock_gettime(CLOCK_REALTIME, &tp);
	return tp.tv_sec * 1000000000ULL + tp.tv_nsec;
}

void yield() {
#if PPSSPP_ARCH(X86) || PPSSPP_ARCH(AMD64)
	_mm_pause();
#elif PPSSPP_ARCH(ARM64)
	// Took this out for now. See issue #17877
	// __builtin_arm_isb(15);
#endif
}

#else

double time_now_d() {
	static time_t start;
	struct timeval tv;
	gettimeofday(&tv, nullptr);
	if (start == 0) {
		start = tv.tv_sec;
	}
	return (double)(tv.tv_sec - start) + (double)tv.tv_usec * (1.0 / micros);
}

uint64_t time_now_raw() {
	static time_t start;
	struct timeval tv;
	gettimeofday(&tv, nullptr);
	if (start == 0) {
		start = tv.tv_sec;
	}
	return (double)tv.tv_sec + (double)tv.tv_usec * (1.0 / micros);
}

double from_time_raw(uint64_t raw_time) {
	return (double)raw_time * (1.0 / nanos);
}

double from_time_raw_relative(uint64_t raw_time) {
	return from_time_raw(raw_time);
}

void yield() {}

double time_now_unix_utc() {
	return time_now_raw();
}

#endif

void sleep_ms(int ms) {
#ifdef _WIN32
	Sleep(ms);
#elif defined(HAVE_LIBNX)
	svcSleepThread(ms * 1000000);
#elif defined(__EMSCRIPTEN__)
	emscripten_sleep(ms);
#else
	usleep(ms * 1000);
#endif
}

// Return the current time formatted as Minutes:Seconds:Milliseconds
// in the form 00:00:000.
void GetTimeFormatted(char formattedTime[13]) {
	time_t sysTime;
	time(&sysTime);

	uint32_t milliseconds;
#ifdef _WIN32
	struct timeb tp;
	(void)::ftime(&tp);
	milliseconds = tp.millitm;
#else
	struct timeval t;
	(void)gettimeofday(&t, NULL);
	milliseconds = (int)(t.tv_usec / 1000);
#endif

	struct tm *gmTime = localtime(&sysTime);
	char tmp[6];
	strftime(tmp, sizeof(tmp), "%M:%S", gmTime);

	// Now tack on the milliseconds
	snprintf(formattedTime, 11, "%s:%03u", tmp, milliseconds % 1000);
}