//go:build linux

package service

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
)

func newPlatformManager(configDir string) (platformManager, error) {
	return &linuxServiceManager{configDir: configDir}, nil
}

// linuxServiceManager manages services via systemd. Direct port of
// LinuxServiceManager in service_manager.py.
type linuxServiceManager struct {
	configDir string
}

func (l *linuxServiceManager) serviceFilePath(name string) string {
	return filepath.Join("/etc/systemd/system", name+".service")
}

func (l *linuxServiceManager) createServiceFile(cfg Config) error {
	execStart := cfg.ExecutablePath
	if cfg.Args != "" {
		execStart += " " + cfg.Args
	}

	description := cfg.Description
	if description == "" {
		description = cfg.Name
	}

	content := fmt.Sprintf(`[Unit]
Description=%s
After=network.target

[Service]
Type=simple
ExecStart=%s
Restart=always
RestartSec=10
User=root

[Install]
WantedBy=multi-user.target
`, description, execStart)

	servicePath := l.serviceFilePath(cfg.Name)
	if err := os.WriteFile(servicePath, []byte(content), 0o644); err != nil {
		return fmt.Errorf("failed to create service file: %w", err)
	}
	return nil
}

func (l *linuxServiceManager) Install(cfg Config) error {
	if err := l.createServiceFile(cfg); err != nil {
		return err
	}

	if out, err := exec.Command("systemctl", "daemon-reload").CombinedOutput(); err != nil {
		return fmt.Errorf("failed to install service: %s", out)
	}
	if out, err := exec.Command("systemctl", "enable", cfg.Name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to install service: %s", out)
	}
	if out, err := exec.Command("systemctl", "start", cfg.Name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to install service: %s", out)
	}
	return nil
}

func (l *linuxServiceManager) Uninstall(name string) error {
	exec.Command("systemctl", "stop", name).Run()

	if out, err := exec.Command("systemctl", "disable", name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to uninstall service: %s", out)
	}

	servicePath := l.serviceFilePath(name)
	if _, err := os.Stat(servicePath); err == nil {
		os.Remove(servicePath)
	}

	if out, err := exec.Command("systemctl", "daemon-reload").CombinedOutput(); err != nil {
		return fmt.Errorf("failed to uninstall service: %s", out)
	}
	return nil
}

func (l *linuxServiceManager) Start(name string) error {
	if out, err := exec.Command("systemctl", "start", name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to start service: %s", out)
	}
	return nil
}

func (l *linuxServiceManager) Stop(name string) error {
	if out, err := exec.Command("systemctl", "stop", name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to stop service: %s", out)
	}
	return nil
}

func (l *linuxServiceManager) Restart(name string) error {
	if out, err := exec.Command("systemctl", "restart", name).CombinedOutput(); err != nil {
		return fmt.Errorf("failed to restart service: %s", out)
	}
	return nil
}