clanker-saddle/src/actions/ProfileActions.vala

using Inversion;
using Spry;
using Spry.Authentication;
using Statum;
using ClankerSaddle.Services;

namespace ClankerSaddle {

    /**
     * The shipped Spry change-own-password action with this app's
     * post-change destination (the profile page) - the form fields and
     * verification (current/new/confirm) are Spry's.
     */
    public class ChangeMyPasswordAction : Spry.Actions.ChangePasswordAction {

        protected override string login_uri { get { return "/login"; } }
    }

    /**
     * The public shape of the DEVICE-scope `ui` slot (goal 41 task 2):
     * the theme + colour mode the client applies to
     * `document.documentElement` (`data-theme`/`data-mode`). Plain
     * strings on purpose — the slot is cached client-side across
     * sessions, so it must stay readable by old frames.
     */
    public class UiSlotPublic : Object {
        /** The Spry theme slug ("" = the core default). */
        public string theme { get; set; default = ""; }
        /** auto | light | dark. */
        public string mode { get; set; default = MODE_DEFAULT; }
    }

    /**
     * Saves the account's appearance choice (goal 41 task 2): the
     * form on /profile posts `theme` (the Spry core default "" or one
     * of the seven shipped theme slugs) and `mode`
     * (auto|light|dark). The choice is persisted per user in
     * `user_preferences` AND written to the DEVICE-scope `ui` slot —
     * the client's theme hook reads that slot on init and after every
     * statum render, so the new look applies immediately and survives
     * sessions on this device.
     */
    public class SetThemeAction : StatumAction {

        /** The seven optional themes shipped with Spry 0.3. */
        public const string[] THEME_SLUGS = {
            "airy", "dwarf", "formal", "glassy", "h2o", "living-sky", "modern"
        };

        /** The three colour modes. */
        public const string[] MODES = { "auto", "light", "dark" };

        /** The DEVICE-scope slot type the client theme hook reads. */
        public const string UI_SLOT_TYPE = "ui";

        private UserService users = inject<UserService>();
        private UserPreferenceService preferences = inject<UserPreferenceService>();

        /** True when `slug` names a theme the client may apply. */
        public static bool is_valid_theme(string slug) {
            if (slug == "" || slug == "core") {
                return true;
            }
            foreach (string candidate in THEME_SLUGS) {
                if (candidate == slug) {
                    return true;
                }
            }
            return false;
        }

        /** True when `mode` is a colour mode the client may apply. */
        public static bool is_valid_mode(string mode) {
            foreach (string candidate in MODES) {
                if (candidate == mode) {
                    return true;
                }
            }
            return false;
        }

        public override async DirectiveBuilder handle() throws GLib.Error {
            var guard = yield SpryAuth.require_login(directives(), request, users);
            if (guard != null) {
                return (!)guard;
            }

            string theme = Forms.field(request, "theme");
            string mode = Forms.field(request, "mode");
            if (mode.length == 0) {
                mode = MODE_DEFAULT;
            }

            if (!is_valid_theme(theme)) {
                return directives().notify("error",
                    "Unknown theme '" + theme + "' - pick one of the themes offered below");
            }
            if (!is_valid_mode(mode)) {
                return directives().notify("error",
                    "Unknown colour mode '" + mode + "' - use auto, light or dark");
            }

            var me = SpryAuth.current(request);
            try {
                yield preferences.set_theme(me.user_id, theme);
                yield preferences.set_mode(me.user_id, mode);
                var slot = new UiSlotPublic() { theme = theme, mode = mode };
                return directives()
                    .set_typed<UiSlotPublic>(UI_SLOT_TYPE, Statum.Scope.DEVICE, slot)
                    .notify("success", "Appearance saved — the new theme applies immediately");
            } catch (Error e) {
                return directives().notify("error",
                    @"Could not save the appearance choice: $(e.message)");
            }
        }
    }
}