//go:build windows

package compose

import (
	"context"
	"io"
	"os/exec"
	"strconv"
	"syscall"
	"time"
)

const finalTerminationBound = 2 * time.Second
const processTreeTerminationBound = 2 * time.Second
const createNewProcessGroup = 0x00000200

func configureProcess(command *exec.Cmd) {
	command.SysProcAttr = &syscall.SysProcAttr{CreationFlags: createNewProcessGroup}
}

func terminateProcess(command *exec.Cmd, done <-chan error) error {
	if command.Process == nil {
		return nil
	}
	treeErr := terminateWindowsProcessTree(command.Process.Pid)
	_ = command.Process.Kill()
	select {
	case <-done:
		if treeErr != nil {
			return ErrProcessReap
		}
		return nil
	case <-time.After(finalTerminationBound):
		return ErrProcessReap
	}
}

func terminateWindowsProcessTree(pid int) error {
	ctx, cancel := context.WithTimeout(context.Background(), processTreeTerminationBound)
	defer cancel()
	command := windowsTreeKillCommand(ctx, pid)
	command.Stdout = io.Discard
	command.Stderr = io.Discard
	if err := command.Run(); err != nil {
		return ErrProcessReap
	}
	if ctx.Err() != nil {
		return ErrProcessReap
	}
	return nil
}

func windowsTreeKillCommand(ctx context.Context, pid int) *exec.Cmd {
	return exec.CommandContext(ctx, "taskkill.exe", "/PID", strconv.Itoa(pid), "/T", "/F")
}