package httpapi

import (
	"log/slog"
	"net/http"
	"strings"

	"github.com/mitbringsl/backend/internal/auth"
)

// MeHandler exposes the authenticated user's own profile (/api/me).
type MeHandler struct {
	users *auth.UserStore
}

// NewMeHandler constructs a MeHandler.
func NewMeHandler(users *auth.UserStore) *MeHandler {
	return &MeHandler{users: users}
}

type updateMeRequest struct {
	DisplayName *string `json:"display_name"` // nil = unchanged, "" = clear
}

// Get returns the current user's profile.
// GET /api/me
func (h *MeHandler) Get(w http.ResponseWriter, r *http.Request) {
	userID, ok := userIDFromCtx(r)
	if !ok {
		renderError(w, http.StatusUnauthorized, "Unauthorized", "Missing user context.")
		return
	}
	u, err := h.users.GetUserByID(r.Context(), userID)
	if err != nil {
		slog.Error("get me failed", "error", err, "user_id", userID)
		renderError(w, http.StatusInternalServerError, "Internal error", "Could not load user.")
		return
	}
	renderJSON(w, http.StatusOK, toUserDTO(u))
}

// Update changes editable fields of the current user (currently display_name).
// PUT /api/me
func (h *MeHandler) Update(w http.ResponseWriter, r *http.Request) {
	userID, ok := userIDFromCtx(r)
	if !ok {
		renderError(w, http.StatusUnauthorized, "Unauthorized", "Missing user context.")
		return
	}
	var req updateMeRequest
	if !decodeJSON(w, r, &req) {
		return
	}

	// Only update when display_name is provided in the body (pointer non-nil).
	// Trimming to keep stored names tidy; an empty string clears the field.
	if req.DisplayName == nil {
		// Nothing to change – return the current profile.
		u, err := h.users.GetUserByID(r.Context(), userID)
		if err != nil {
			renderError(w, http.StatusInternalServerError, "Internal error", "Could not load user.")
			return
		}
		renderJSON(w, http.StatusOK, toUserDTO(u))
		return
	}

	name := strings.TrimSpace(*req.DisplayName)
	u, err := h.users.UpdateDisplayName(r.Context(), userID, name)
	if err != nil {
		slog.Error("update me failed", "error", err, "user_id", userID)
		renderError(w, http.StatusInternalServerError, "Internal error", "Could not update user.")
		return
	}
	renderJSON(w, http.StatusOK, toUserDTO(u))
}