// Module Services — gestion des services systemd via SSH.
// Expose : liste des services, statut détaillé, start/stop/restart (admin).
package services

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"strings"

	"git.geronzi.fr/proxmoxPanel/core/backend/internal/api"
	"git.geronzi.fr/proxmoxPanel/core/backend/internal/crypto"
	"git.geronzi.fr/proxmoxPanel/core/backend/internal/db"
	sshpool "git.geronzi.fr/proxmoxPanel/core/backend/internal/ssh"
	"git.geronzi.fr/proxmoxPanel/core/backend/modules"
	"github.com/go-chi/chi/v5"
)

// ServicesModule gère les opérations systemctl sur le host et les LXC.
type ServicesModule struct {
	db   *db.DB
	pool *sshpool.Pool
	enc  *crypto.Encryptor
}

// New crée un ServicesModule avec les dépendances nécessaires.
func New(database *db.DB, pool *sshpool.Pool, enc *crypto.Encryptor) *ServicesModule {
	return &ServicesModule{db: database, pool: pool, enc: enc}
}

func (m *ServicesModule) ID() string { return "services" }

// Register enregistre les routes du module dans le registry CORE.
func (m *ServicesModule) Register(r modules.Registry) error {
	r.RegisterRoute("GET",  "/api/services",                m.ListServices,   false)
	r.RegisterRoute("GET",  "/api/services/{name}/status",  m.ServiceStatus,  false)
	r.RegisterRoute("POST", "/api/services/{name}/{action}", m.ServiceAction, true)
	return nil
}

// sshCreds récupère et déchiffre les credentials SSH depuis la configuration.
func (m *ServicesModule) sshCreds() (host, user, pass string, err error) {
	host, _, _ = m.db.GetSetting("ssh_host")
	user, _, _ = m.db.GetSetting("ssh_username")
	encPass, _, _ := m.db.GetSetting("ssh_password")
	if encPass != "" {
		pass, err = m.enc.Decrypt(encPass)
		if err != nil {
			return "", "", "", fmt.Errorf("impossible de déchiffrer le mot de passe SSH")
		}
	}
	if host == "" || user == "" || pass == "" {
		return "", "", "", fmt.Errorf("SSH non configuré")
	}
	return host, user, pass, nil
}

// buildCmd construit la commande systemctl, en la wrappant via pct exec pour les LXC.
func buildCmd(target, systemctlArgs string) string {
	if strings.HasPrefix(target, "lxc:") {
		vmid := strings.TrimPrefix(target, "lxc:")
		if _, err := strconv.Atoi(vmid); err == nil {
			return fmt.Sprintf("pct exec %s -- systemctl %s", vmid, systemctlArgs)
		}
	}
	return "systemctl " + systemctlArgs
}

// ServiceEntry représente un service systemd dans la liste.
type ServiceEntry struct {
	Name        string `json:"name"`
	LoadState   string `json:"load_state"`
	ActiveState string `json:"active_state"`
	SubState    string `json:"sub_state"`
	Description string `json:"description"`
}

// ListServices retourne la liste des services systemd d'une cible.
// GET /api/services?target=host|lxc:ID
func (m *ServicesModule) ListServices(w http.ResponseWriter, r *http.Request) {
	host, user, pass, err := m.sshCreds()
	if err != nil {
		api.JSONError(w, err.Error(), http.StatusServiceUnavailable)
		return
	}

	target := r.URL.Query().Get("target")
	if target == "" {
		target = "host"
	}

	cmd := buildCmd(target, "list-units --type=service --all --no-legend --plain --no-pager 2>/dev/null")
	out, err := m.pool.RunCommand(host, user, pass, cmd)
	if err != nil {
		api.JSONError(w, "Erreur commande SSH : "+err.Error(), http.StatusInternalServerError)
		return
	}

	services := parseServiceList(out)
	api.JSONResponse(w, http.StatusOK, services)
}

// parseServiceList parse la sortie de systemctl list-units.
// Format : "nom.service   load   active   running   Description..."
func parseServiceList(output string) []ServiceEntry {
	var services []ServiceEntry
	for _, line := range strings.Split(output, "\n") {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "UNIT") || strings.HasPrefix(line, "Legend") ||
			strings.HasPrefix(line, "To show") || strings.HasPrefix(line, "Pass") {
			continue
		}
		// Certaines lignes commencent par "●" (service failed) — on supprime ce caractère
		line = strings.TrimPrefix(line, "● ")
		line = strings.TrimPrefix(line, "  ")

		fields := strings.Fields(line)
		if len(fields) < 4 {
			continue
		}
		name := strings.TrimSuffix(fields[0], ".service")
		desc := ""
		if len(fields) >= 5 {
			desc = strings.Join(fields[4:], " ")
		}
		services = append(services, ServiceEntry{
			Name:        name,
			LoadState:   fields[1],
			ActiveState: fields[2],
			SubState:    fields[3],
			Description: desc,
		})
	}
	return services
}

// ServiceStatus retourne le statut détaillé d'un service.
// GET /api/services/{name}/status?target=host|lxc:ID
func (m *ServicesModule) ServiceStatus(w http.ResponseWriter, r *http.Request) {
	host, user, pass, err := m.sshCreds()
	if err != nil {
		api.JSONError(w, err.Error(), http.StatusServiceUnavailable)
		return
	}

	name := chi.URLParam(r, "name")
	target := r.URL.Query().Get("target")
	if target == "" {
		target = "host"
	}

	cmd := buildCmd(target, fmt.Sprintf("status %s --no-pager 2>&1", name))
	out, _ := m.pool.RunCommand(host, user, pass, cmd)

	api.JSONResponse(w, http.StatusOK, map[string]string{"output": out})
}

// ServiceAction exécute une action (start/stop/restart/reload) sur un service.
// POST /api/services/{name}/{action}
// Body: { "target": "host" | "lxc:ID" }
func (m *ServicesModule) ServiceAction(w http.ResponseWriter, r *http.Request) {
	host, user, pass, err := m.sshCreds()
	if err != nil {
		api.JSONError(w, err.Error(), http.StatusServiceUnavailable)
		return
	}

	name   := chi.URLParam(r, "name")
	action := chi.URLParam(r, "action")

	// Valider l'action pour éviter l'injection de commandes
	allowed := map[string]bool{"start": true, "stop": true, "restart": true, "reload": true, "enable": true, "disable": true}
	if !allowed[action] {
		api.JSONError(w, "Action invalide", http.StatusBadRequest)
		return
	}

	var body struct {
		Target string `json:"target"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.Target == "" {
		body.Target = "host"
	}

	cmd := buildCmd(body.Target, fmt.Sprintf("%s %s 2>&1", action, name))
	out, err := m.pool.RunCommand(host, user, pass, cmd)

	if err != nil {
		api.JSONError(w, fmt.Sprintf("Erreur action %s sur %s : %v\n%s", action, name, err, out), http.StatusInternalServerError)
		return
	}

	api.JSONResponse(w, http.StatusOK, map[string]string{
		"message": fmt.Sprintf("Action « %s » exécutée sur %s", action, name),
		"output":  out,
	})
}