package handlers

import (
	"encoding/json"
	"log"
	"net/http"
	"regexp"
)

var validUsername = regexp.MustCompile(`^[a-z0-9][a-z0-9_-]*$`)

// handleDeleteUser fully deletes an account plus its customer stack and volumes.
// Requires ADMIN_SECRET env set and X-Admin-Secret header. POST /admin/delete-user?user=instance-slug
func (a *App) handleDeleteUser(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	if a.cfg.AdminSecret == "" {
		http.NotFound(w, r)
		return
	}
	secret := r.Header.Get("X-Admin-Secret")
	if secret != a.cfg.AdminSecret {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	slug := r.URL.Query().Get("user")
	if slug == "" {
		slug = r.FormValue("user")
	}
	if slug == "" {
		http.Error(w, "user required", http.StatusBadRequest)
		return
	}
	if !validUsername.MatchString(slug) {
		http.Error(w, "invalid username", http.StatusBadRequest)
		return
	}

	inst, err := a.accounts.DeleteAccountByInstanceSlug(r.Context(), slug)
	if err != nil {
		log.Printf("admin delete-user %s: account: %v", slug, err)
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(map[string]string{"error": err.Error()})
		return
	}

	if err := a.swarm.RemoveStackAndVolumes(inst.StackName); err != nil {
		log.Printf("admin delete-user %s: stack/volumes: %v", slug, err)
		// Account already deleted; report but don't fail.
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		json.NewEncoder(w).Encode(map[string]string{
			"status":  "user deleted",
			"warning": "stack/volumes: " + err.Error(),
		})
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "deleted", "user": slug})
}