package svcmgr

import (
	"fmt"
	"os/exec"
	"runtime"
	"strings"
)

type ServiceInfo struct {
	Name    string `json:"name"`
	Status  string `json:"status"`
	Enabled bool   `json:"enabled"`
}

func ListServices() ([]ServiceInfo, error) {
	switch runtime.GOOS {
	case "windows":
		return listWindowsServices()
	case "darwin":
		return listDarwinServices()
	default:
		return listLinuxServices()
	}
}

func GetServiceStatus(name string) (string, bool, error) {
	switch runtime.GOOS {
	case "windows":
		return getWindowsServiceStatus(name)
	case "darwin":
		return getDarwinServiceStatus(name)
	default:
		return getLinuxServiceStatus(name)
	}
}

func StartService(name string) (string, error) {
	switch runtime.GOOS {
	case "windows":
		return startWindowsService(name)
	case "darwin":
		return startDarwinService(name)
	default:
		return startLinuxService(name)
	}
}

func StopService(name string) (string, error) {
	switch runtime.GOOS {
	case "windows":
		return stopWindowsService(name)
	case "darwin":
		return stopDarwinService(name)
	default:
		return stopLinuxService(name)
	}
}

func RestartService(name string) (string, error) {
	switch runtime.GOOS {
	case "windows":
		return restartWindowsService(name)
	case "darwin":
		return restartDarwinService(name)
	default:
		return restartLinuxService(name)
	}
}

func Reboot() error {
	switch runtime.GOOS {
	case "windows":
		return exec.Command("shutdown", "/r", "/t", "0").Run()
	case "darwin":
		return exec.Command("sudo", "shutdown", "-r", "now").Run()
	default:
		return exec.Command("sudo", "reboot").Run()
	}
}

func Shutdown() error {
	switch runtime.GOOS {
	case "windows":
		return exec.Command("shutdown", "/s", "/t", "0").Run()
	case "darwin":
		return exec.Command("sudo", "shutdown", "-h", "now").Run()
	default:
		return exec.Command("sudo", "poweroff").Run()
	}
}

func listWindowsServices() ([]ServiceInfo, error) {
	out, err := exec.Command("powershell", "-NoProfile", "-NonInteractive", "-Command",
		"Get-Service -ErrorAction SilentlyContinue | ForEach-Object { '{0}`t{1}`t{2}' -f $_.Name, $_.Status, $_.StartType }").Output()
	if err != nil {
		return nil, fmt.Errorf("Get-Service failed: %w", err)
	}

	var services []ServiceInfo
	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
		fields := strings.Split(strings.TrimSpace(line), "\t")
		if len(fields) < 3 {
			continue
		}
		services = append(services, ServiceInfo{
			Name:    fields[0],
			Status:  strings.ToLower(fields[1]),
			Enabled: strings.EqualFold(fields[2], "Automatic"),
		})
	}
	return services, nil
}

func getWindowsServiceStatus(name string) (string, bool, error) {
	out, err := exec.Command("powershell", "-NoProfile", "-NonInteractive", "-Command",
		fmt.Sprintf("$s = Get-Service -Name '%s' -ErrorAction Stop; '{0}`t{1}' -f $s.Status, $s.StartType", name)).Output()
	if err != nil {
		return "", false, fmt.Errorf("Get-Service failed: %w", err)
	}
	fields := strings.Split(strings.TrimSpace(string(out)), "\t")
	if len(fields) < 2 {
		return "", false, fmt.Errorf("unexpected Get-Service output: %s", strings.TrimSpace(string(out)))
	}
	return strings.ToLower(fields[0]), strings.EqualFold(fields[1], "Automatic"), nil
}

func startWindowsService(name string) (string, error) {
	cmd := exec.Command("powershell", "-NoProfile", "-NonInteractive", "-Command",
		fmt.Sprintf("Start-Service -Name '%s' -ErrorAction Stop", name))
	if out, err := cmd.CombinedOutput(); err != nil {
		return string(out), fmt.Errorf("start failed: %w\nOutput: %s", err, string(out))
	}
	return "started", nil
}

func stopWindowsService(name string) (string, error) {
	cmd := exec.Command("powershell", "-NoProfile", "-NonInteractive", "-Command",
		fmt.Sprintf("Stop-Service -Name '%s' -ErrorAction Stop", name))
	if out, err := cmd.CombinedOutput(); err != nil {
		return string(out), fmt.Errorf("stop failed: %w\nOutput: %s", err, string(out))
	}
	return "stopped", nil
}

func restartWindowsService(name string) (string, error) {
	cmd := exec.Command("powershell", "-NoProfile", "-NonInteractive", "-Command",
		fmt.Sprintf("Restart-Service -Name '%s' -ErrorAction Stop", name))
	if out, err := cmd.CombinedOutput(); err != nil {
		return string(out), fmt.Errorf("restart failed: %w\nOutput: %s", err, string(out))
	}
	return "restarted", nil
}

func listDarwinServices() ([]ServiceInfo, error) {
	out, err := exec.Command("launchctl", "list").Output()
	if err != nil {
		return nil, fmt.Errorf("launchctl list failed: %w", err)
	}

	var services []ServiceInfo
	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n")[1:] {
		fields := strings.Fields(line)
		if len(fields) < 3 {
			continue
		}
		status := "unknown"
		if fields[0] != "-" {
			status = "running"
		}
		services = append(services, ServiceInfo{
			Name:   fields[2],
			Status: status,
		})
	}
	return services, nil
}

func getDarwinServiceStatus(name string) (string, bool, error) {
	out, err := exec.Command("launchctl", "list").Output()
	if err != nil {
		return "", false, fmt.Errorf("launchctl list failed: %w", err)
	}
	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n")[1:] {
		fields := strings.Fields(line)
		if len(fields) >= 3 && fields[2] == name {
			if fields[0] != "-" {
				return "running", true, nil
			}
			return "inactive", false, nil
		}
	}
	return "not_found", false, nil
}

func startDarwinService(name string) (string, error) {
	cmd := exec.Command("launchctl", "load", fmt.Sprintf("/Library/LaunchDaemons/%s.plist", name))
	if out, err := cmd.CombinedOutput(); err != nil {
		return string(out), fmt.Errorf("start failed: %w\nOutput: %s", err, string(out))
	}
	return "started", nil
}

func stopDarwinService(name string) (string, error) {
	cmd := exec.Command("launchctl", "unload", fmt.Sprintf("/Library/LaunchDaemons/%s.plist", name))
	if out, err := cmd.CombinedOutput(); err != nil {
		return string(out), fmt.Errorf("stop failed: %w\nOutput: %s", err, string(out))
	}
	return "stopped", nil
}

func restartDarwinService(name string) (string, error) {
	stopDarwinService(name)
	return startDarwinService(name)
}

func listLinuxServices() ([]ServiceInfo, error) {
	cmd := exec.Command("systemctl", "list-units", "--type=service", "--all", "--no-pager", "--no-legend", "--plain", "--no-accept-unknown")
	out, err := cmd.Output()
	if err != nil {
		return nil, fmt.Errorf("systemctl list-units failed: %w", err)
	}

	var services []ServiceInfo
	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}
		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}

		svcName := strings.TrimSuffix(fields[0], ".service")
		status := fields[2]
		enabled := fields[3] == "loaded"

		services = append(services, ServiceInfo{
			Name:    svcName,
			Status:  status,
			Enabled: enabled,
		})
	}
	return services, nil
}

func getLinuxServiceStatus(name string) (string, bool, error) {
	cmd := exec.Command("systemctl", "is-active", name)
	out, err := cmd.Output()
	status := strings.TrimSpace(string(out))

	enabledCmd := exec.Command("systemctl", "is-enabled", name)
	enabledOut, _ := enabledCmd.Output()
	enabled := strings.TrimSpace(string(enabledOut)) == "enabled"

	if err != nil && status != "inactive" {
		return status, enabled, fmt.Errorf("systemctl status failed: %w", err)
	}
	return status, enabled, nil
}

func startLinuxService(name string) (string, error) {
	cmd := exec.Command("sudo", "systemctl", "start", name)
	out, err := cmd.CombinedOutput()
	if err != nil {
		return string(out), fmt.Errorf("start failed: %w\nOutput: %s", err, string(out))
	}
	return "started", nil
}

func stopLinuxService(name string) (string, error) {
	cmd := exec.Command("sudo", "systemctl", "stop", name)
	out, err := cmd.CombinedOutput()
	if err != nil {
		return string(out), fmt.Errorf("stop failed: %w\nOutput: %s", err, string(out))
	}
	return "stopped", nil
}

func restartLinuxService(name string) (string, error) {
	cmd := exec.Command("sudo", "systemctl", "restart", name)
	out, err := cmd.CombinedOutput()
	if err != nil {
		return string(out), fmt.Errorf("restart failed: %w\nOutput: %s", err, string(out))
	}
	return "restarted", nil
}