package main

/*
#include <windows.h>
BOOL SetPriority(DWORD pid, int priority) {
    HANDLE h = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
    if (!h) return FALSE;
    BOOL success = SetPriorityClass(h, priority);
    CloseHandle(h);
    return success;
}
*/
import "C"
import (
	"github.com/postfinance/single"
	"github.com/shirou/gopsutil/process"
	"os"
	"runtime"
	"syscall"
	"time"
	"unsafe"
)

func MessageBox(lpText string, lpCaption string, uType int) int {
	var convertedCaption, _ = syscall.UTF16PtrFromString(lpCaption)
	var convertedTitle, _ = syscall.UTF16PtrFromString(lpText)
	returnCode, _, _ := syscall.NewLazyDLL("user32.dll").NewProc("MessageBoxW").Call(
		uintptr(0),
		uintptr(unsafe.Pointer(convertedCaption)),
		uintptr(unsafe.Pointer(convertedTitle)),
		uintptr(uType),
	)
	return int(returnCode)
}

var lockFile, _ = single.New("autoPriority")

func main() {
	if err := lockFile.Lock(); err != nil {
		MessageBox("The program is already running", "Only one instance of the program can be run\nYou can close it via the Task Manager", 48)
		os.Exit(1)
	}

	C.SetPriority(C.DWORD(os.Getpid()), 0x00000040)
	for range time.Tick(time.Minute) {
		processes, _ := process.Processes()
		for _, proc := range processes {
			memoryInfo, err := proc.MemoryInfo()
			if err == nil && memoryInfo.RSS >= (0.5*1024*1024*1024) {
				C.SetPriority(C.DWORD(proc.Pid), 0x00000080)
			}
		}
		runtime.GC()
	}
}