package app

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
)

func runRoutesServiceAction(action string) cmdResult {
	action = strings.ToLower(strings.TrimSpace(action))
	unit := routesServiceUnitName()
	if unit == "" {
		return cmdResult{
			OK:      false,
			Message: "routes service unit unresolved: set preferred iface or SELECTIVE_VPN_ROUTES_UNIT",
		}
	}

	var args []string
	switch action {
	case "start", "stop", "restart":
		args = []string{"systemctl", action, unit}
	default:
		return cmdResult{
			OK:      false,
			Message: "unknown action (expected start|stop|restart)",
		}
	}

	stdout, stderr, exitCode, err := runCommand(args[0], args[1:]...)
	res := cmdResult{
		OK:       err == nil && exitCode == 0,
		ExitCode: exitCode,
		Stdout:   stdout,
		Stderr:   stderr,
	}
	if err != nil {
		res.Message = err.Error()
	} else {
		res.Message = fmt.Sprintf("%s done (%s)", action, unit)
	}
	return res
}

func makeRoutesServiceActionHandler(action string) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
			return
		}
		res := runRoutesServiceAction(action)
		writeJSON(w, http.StatusOK, res)
	}
}

// POST /api/v1/routes/service { "action": "start|stop|restart" }
// ---------------------------------------------------------------------
// EN: `handleRoutesService` is an HTTP handler for routes service.
// RU: `handleRoutesService` - HTTP-обработчик для routes service.
// ---------------------------------------------------------------------
func handleRoutesService(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}

	var body struct {
		Action string `json:"action"`
	}
	if r.Body != nil {
		defer r.Body.Close()
		_ = json.NewDecoder(io.LimitReader(r.Body, 1<<20)).Decode(&body)
	}

	res := runRoutesServiceAction(body.Action)
	if strings.Contains(res.Message, "unknown action") {
		writeJSON(w, http.StatusBadRequest, res)
		return
	}
	writeJSON(w, http.StatusOK, res)
}