package builtin

import (
	"context"
	"fmt"

	"github.com/vladimir/goherence/internal/module"
	"github.com/vladimir/goherence/internal/ssh"
)

// SystemdModule — аналог ansible.builtin.systemd: приводит сервис
// к желаемому состоянию (started/stopped) и/или включает автозапуск (enabled).
type SystemdModule struct{}

func (m *SystemdModule) Name() string { return "systemd" }

func (m *SystemdModule) Run(ctx context.Context, in module.Input, conn *ssh.Conn) (module.Result, error) {
	name, ok := in.Args["name"].(string)
	if !ok {
		return module.Result{}, fmt.Errorf("systemd: аргумент name обязателен")
	}
	state, _ := in.Args["state"].(string)
	enabledArg, hasEnabled := in.Args["enabled"].(bool)

	changed := false
	var actions []string

	if state != "" {
		active, err := m.isActive(conn, name)
		if err != nil {
			return module.Result{}, err
		}
		wantActive := state == "started"
		if state == "restarted" {
			actions = append(actions, "systemctl restart "+shArg(name))
			changed = true
		} else if active != wantActive {
			verb := "stop"
			if wantActive {
				verb = "start"
			}
			actions = append(actions, "systemctl "+verb+" "+shArg(name))
			changed = true
		}
	}

	if hasEnabled {
		enabled, err := m.isEnabled(conn, name)
		if err != nil {
			return module.Result{}, err
		}
		if enabled != enabledArg {
			verb := "disable"
			if enabledArg {
				verb = "enable"
			}
			actions = append(actions, "systemctl "+verb+" "+shArg(name))
			changed = true
		}
	}

	if !changed {
		return module.Result{SchemaVersion: module.SchemaVersion, Changed: false, Msg: name + ": уже в нужном состоянии"}, nil
	}
	if in.CheckMode {
		return module.Result{SchemaVersion: module.SchemaVersion, Changed: true, Msg: fmt.Sprintf("check mode: %v", actions)}, nil
	}

	for _, action := range actions {
		res, err := conn.Run(action)
		if err != nil {
			return module.Result{}, err
		}
		if res.ExitCode != 0 {
			return module.Result{SchemaVersion: module.SchemaVersion, Failed: true,
				Msg: fmt.Sprintf("%q завершилась с кодом %d: %s", action, res.ExitCode, res.Stderr)}, nil
		}
	}
	return module.Result{SchemaVersion: module.SchemaVersion, Changed: true, Msg: fmt.Sprintf("%v", actions)}, nil
}

func (m *SystemdModule) isActive(conn *ssh.Conn, name string) (bool, error) {
	res, err := conn.Run("systemctl is-active " + shArg(name))
	if err != nil {
		return false, err
	}
	return res.ExitCode == 0, nil
}

func (m *SystemdModule) isEnabled(conn *ssh.Conn, name string) (bool, error) {
	res, err := conn.Run("systemctl is-enabled " + shArg(name))
	if err != nil {
		return false, err
	}
	return res.ExitCode == 0, nil
}