import type { Profile } from '$lib/types';
import { alertAction } from '$lib/client/confirm.svelte';

const STORAGE_KEY = 'kochwas.activeProfileId';

function loadActiveId(): number | null {
  if (typeof localStorage === 'undefined') return null;
  const raw = localStorage.getItem(STORAGE_KEY);
  if (!raw) return null;
  const n = Number(raw);
  return Number.isInteger(n) && n > 0 ? n : null;
}

function saveActiveId(id: number | null): void {
  if (typeof localStorage === 'undefined') return;
  if (id === null) localStorage.removeItem(STORAGE_KEY);
  else localStorage.setItem(STORAGE_KEY, String(id));
}

class ProfileStore {
  profiles = $state<Profile[]>([]);
  activeId = $state<number | null>(null);
  loaded = $state(false);

  active = $derived(this.profiles.find((p) => p.id === this.activeId) ?? null);

  async load(): Promise<void> {
    const res = await fetch('/api/profiles');
    this.profiles = await res.json();
    const stored = loadActiveId();
    if (stored && this.profiles.some((p) => p.id === stored)) {
      this.activeId = stored;
    }
    this.loaded = true;
  }

  select(id: number): void {
    this.activeId = id;
    saveActiveId(id);
  }

  clear(): void {
    this.activeId = null;
    saveActiveId(null);
  }

  async create(name: string, avatar_emoji: string | null): Promise<Profile> {
    const res = await fetch('/api/profiles', {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({ name, avatar_emoji })
    });
    if (!res.ok) {
      const err = await res.json().catch(() => ({ message: 'unknown error' }));
      throw new Error(err.message ?? 'failed to create profile');
    }
    const p = (await res.json()) as Profile;
    this.profiles = [...this.profiles, p].sort((a, b) => a.name.localeCompare(b.name));
    return p;
  }
}

export const profileStore = new ProfileStore();

/**
 * Returns the active profile, or null after showing the standard
 * "kein Profil gewählt" dialog. Use as the first line of any per-profile
 * action so we don't repeat the guard at every call-site.
 *
 * `message` ueberschreibt den Default, wenn eine Aktion einen spezifischen
 * Hinweis braucht (z. B. „um mitzuwünschen" auf der Wunschliste).
 */
export async function requireProfile(
  message = 'Tippe oben rechts auf „Profil wählen", dann klappt die Aktion.'
): Promise<Profile | null> {
  if (profileStore.active) return profileStore.active;
  await alertAction({ title: 'Kein Profil gewählt', message });
  return null;
}