package utils

import (
	"fmt"
	"os"
	"runtime"
	"strconv"
	"syscall"
	"time"
)

// SetOOMScore sets the OOM score adjustment for a process.
// Score range: -1000 (never kill) to 1000 (always kill first).
// Linux-only; returns an error on non-Linux systems.
func SetOOMScore(pid int, score int) error {
	if runtime.GOOS != "linux" {
		return fmt.Errorf("OOM score adjustment is only supported on Linux")
	}
	path := fmt.Sprintf("/proc/%d/oom_score_adj", pid)
	return os.WriteFile(path, []byte(strconv.Itoa(score)), 0600)
}

func StopProcess(serviceName string) error {
	pid, err := ReadPidFile(serviceName)
	if err != nil {
		return err
	}

	err = KillProcess(pid)
	if err != nil {
		return err
	}

	// Remove PID file
	err = RemovePidFile(serviceName)
	if err != nil {
		return err
	}

	return nil
}

func KillProcess(pid int) error {

	process, err := os.FindProcess(pid)

	if err != nil {
		return err
	}

	// Send SIGTERM first (graceful)
	err = process.Signal(syscall.SIGTERM)
	if err != nil {
		return err
	}

	// Check process terminated

	checks := 0
	for {
		time.Sleep(1 * time.Second)
		process, err = os.FindProcess(pid)

		if err != nil {
			return err
		}

		err = process.Signal(syscall.Signal(0))

		if err != nil {
			// Process terminated, break
			break
		}

		checks++

		// If process is still running after 120 seconds, force kill
		if checks > 120 {
			err = process.Kill() // SIGKILL

			if err != nil {
				return err
			}

			break
		}
	}

	return nil

}