//go:build linux

package procctl

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

	"safesight-agent/internal/log"
)

func isAlive(pid int) (bool, error) {
	if pid <= 0 {
		return false, nil
	}
	p, err := os.FindProcess(pid)
	if err != nil {
		return false, err
	}
	if err := p.Signal(syscall.Signal(0)); err != nil {
		return false, nil
	}
	return true, nil
}

func startProcess(execPath, workDir, configPath string) (int, error) {
	cmd := exec.Command(execPath, "--config", configPath)
	cmd.Dir = workDir
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	if err := cmd.Start(); err != nil {
		return 0, fmt.Errorf("start media-server: %w", err)
	}
	pid := cmd.Process.Pid
	go func() {
		err := cmd.Wait()
		if err != nil {
			log.Warn(fmt.Sprintf("media-server exited pid=%d err=%v", pid, err))
		} else {
			log.Info(fmt.Sprintf("media-server exited pid=%d", pid))
		}
	}()
	return pid, nil
}

func stopProcess(pid int, timeout time.Duration) error {
	if pid <= 0 {
		return nil
	}
	p, err := os.FindProcess(pid)
	if err != nil {
		return err
	}
	_ = p.Signal(syscall.SIGTERM)

	deadline := time.Now().Add(timeout)
	for time.Now().Before(deadline) {
		alive, _ := isAlive(pid)
		if !alive {
			return nil
		}
		time.Sleep(100 * time.Millisecond)
	}

	_ = p.Signal(syscall.SIGKILL)
	deadline = time.Now().Add(2 * time.Second)
	for time.Now().Before(deadline) {
		alive, _ := isAlive(pid)
		if !alive {
			return nil
		}
		time.Sleep(100 * time.Millisecond)
	}
	return fmt.Errorf("failed to stop pid=%d", pid)
}