//go:build !windows

package compose

import (
	"os/exec"
	"syscall"
	"time"
)

const gracefulTerminationBound = 500 * time.Millisecond
const finalTerminationBound = 2 * time.Second

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

type unixProcessLifetime struct {
	command *exec.Cmd
}

func startProcess(command *exec.Cmd) (processLifetime, error) {
	if err := command.Start(); err != nil {
		return nil, err
	}
	return unixProcessLifetime{command: command}, nil
}

func (process unixProcessLifetime) terminate(done <-chan error) error {
	return terminateProcess(process.command, done)
}

func (unixProcessLifetime) close() error {
	return nil
}

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