package main

import (
	"syscall"
	"time"
	"unsafe"
)

const (
	TickPerMillisecond int64 = 0x2710
	TicksPerSecond     int64 = 0x989680
)

var (
	modkernel32                   = syscall.NewLazyDLL("kernel32.dll")
	procQueryPerformanceFrequency = modkernel32.NewProc("QueryPerformanceFrequency")
	procQueryPerformanceCounter   = modkernel32.NewProc("QueryPerformanceCounter")
	procSleep                     = modkernel32.NewProc("Sleep")
)

type stopWatch struct {
	elapsed          int64
	startTimeStamp   int64
	isRunning        bool
	start            time.Time
	IsHighResolution bool
	Frequery         int64
	tickFrequery     float64
}

func NewStopWatch() *stopWatch {
	sw := new(stopWatch)
	if err := queryPerformanceFrequency(&sw.Frequery); err != nil {
		sw.IsHighResolution = false
		sw.Frequery = 0x989680
		sw.tickFrequery = 1.0
	} else {
		sw.IsHighResolution = true
		sw.tickFrequery = 10000000.0
		sw.tickFrequery /= float64(sw.Frequery)
	}
	return sw

}
func StartNew() *stopWatch {
	sw := new(stopWatch)
	sw.Start()
	return sw
}
func (this *stopWatch) Reset() {
	this.elapsed = 0
	this.startTimeStamp = 0
	this.isRunning = false
}
func (this *stopWatch) Start() {
	if !this.isRunning {
		this.startTimeStamp = this.getTimestamp()
		this.isRunning = true
	}
}
func (this *stopWatch) Stop() {
	if this.isRunning {
		num2 := this.getTimestamp() - this.startTimeStamp
		this.elapsed += num2
		this.isRunning = false
	}
}
func (this *stopWatch) Elapsed() int64 {
	return this.getElapsedDateTimeTicks()
}
func (this *stopWatch) ElapsedMilliseconds() int64 {
	return this.getElapsedDateTimeTicks() / 0x2710
}
func (this *stopWatch) ElapsedTicks() int64 {
	return this.getRawElapsedTicks()
}
func (this *stopWatch) IsRunning() bool {
	return this.isRunning
}
func (this *stopWatch) getElapsedDateTimeTicks() int64 {
	rawElapsedTicks := this.getRawElapsedTicks()
	if this.IsHighResolution {
		num2 := float64(rawElapsedTicks)
		num2 *= this.tickFrequery
		return int64(num2)
	}
	return rawElapsedTicks
}
func (this *stopWatch) getRawElapsedTicks() int64 {
	elapsed := this.elapsed
	if this.isRunning {
		num3 := this.getTimestamp() - this.startTimeStamp
		elapsed += num3
	}
	return elapsed
}
func (this *stopWatch) getTimestamp() int64 {
	if this.IsHighResolution {
		var num int64
		queryPerformanceCounter(&num)
		return num
	}
	return time.Now().UTC().Unix()
}

func queryPerformanceFrequency(frequency *int64) (err error) {
	r1, _, e1 := syscall.Syscall(procQueryPerformanceFrequency.Addr(), 1, uintptr(unsafe.Pointer(frequency)), 0, 0)
	if r1 == 0 {
		if e1 != 0 {
			err = error(e1)
		} else {
			err = syscall.EINVAL
		}
	}
	return
}

func queryPerformanceCounter(counter *int64) (err error) {
	r1, _, e1 := syscall.Syscall(procQueryPerformanceCounter.Addr(), 1, uintptr(unsafe.Pointer(counter)), 0, 0)
	if r1 == 0 {
		if e1 != 0 {
			err = error(e1)
		} else {
			err = syscall.EINVAL
		}
	}
	return
}

func sleep(milliseconds uint32) {
	syscall.Syscall(procSleep.Addr(), 1, uintptr(milliseconds), 0, 0)
	return
}