import type { components } from '@pipu/api-client';
import { AGE_GROUPS, GENDERS, unwrap } from '@pipu/core';
import { useMutation } from '@tanstack/react-query';
import { useState } from 'react';
import { useTranslation } from 'react-i18next';

import { useSession } from '../app/session';
import { Cover } from '../entities/catalog';
import { useErrorText } from '../shared/lib/errors';
import { checkIcon } from '../shared/ui/icons';
import { Button, cx, FormError, Icon } from '../shared/ui/ui';
import s from './onboarding.module.css';

type Options = components['schemas']['Onboarding'];

/** Минимум исполнителей, чтобы волне было от чего оттолкнуться. */
const MIN_ARTISTS = 3;

/**
 * Онбординг вкуса (docs/recommendations.md#7): исполнители и жанры библиотеки — начальный вкус «Моей волны»,
 * пока своей истории почти нет. Пропуск тоже запоминается: второй раз не спросим.
 */
export function Onboarding({ options, onDone, editing = false }: { options: Options; onDone: () => void; editing?: boolean }) {
  const { t } = useTranslation();
  const session = useSession();
  const errorText = useErrorText();
  const [artists, setArtists] = useState<Set<string>>(new Set(options.choice?.artist_ids));
  const [genres, setGenres] = useState<Set<string>>(new Set(options.choice?.genres));
  const [gender, setGender] = useState(options.choice?.gender ?? null);
  const [ageGroup, setAgeGroup] = useState(options.choice?.age_group ?? null);
  const save = useMutation({
    mutationFn: async (skip: boolean) =>
      unwrap(
        await session.client.PUT('/api/v1/me/onboarding', {
          body: skip ? { artist_ids: [], genres: [], gender: null, age_group: null } : { artist_ids: [...artists], genres: [...genres], gender, age_group: ageGroup },
        }),
      ),
    onSuccess: onDone,
  });
  // Функциональное обновление: быстрые нажатия подряд не теряют выбор.
  const toggle = (update: (fn: (prev: Set<string>) => Set<string>) => void, key: string) =>
    update((prev) => {
      const next = new Set(prev);
      if (next.has(key)) next.delete(key);
      else next.add(key);
      return next;
    });
  const enough = editing || artists.size >= MIN_ARTISTS || (artists.size > 0 && genres.size > 0) || !!gender || !!ageGroup || options.artists.length === 0;

  return (
    <div className={s.page}>
      <header className={s.head}>
        <h1>{t('onboarding.title')}</h1>
        <p>{t('onboarding.subtitle')}</p>
      </header>

      <section aria-label={t('onboarding.gender')}>
        <h2 className={s.label}>{t('onboarding.gender')}</h2>
        <div className={s.genres}>
          <button type="button" className={s.genre} aria-pressed={!gender} onClick={() => setGender(null)}>{t('onboarding.unspecified')}</button>
          {GENDERS.map((g) => <button type="button" key={g} className={s.genre} aria-pressed={gender === g} onClick={() => setGender(g)}>{t(`onboarding.genders.${g}`)}</button>)}
        </div>
      </section>
      <section aria-label={t('onboarding.age_group')}>
        <h2 className={s.label}>{t('onboarding.age_group')}</h2>
        <p>{t('onboarding.age_hint')}</p>
        <div className={s.genres}>
          <button type="button" className={s.genre} aria-pressed={!ageGroup} onClick={() => setAgeGroup(null)}>{t('onboarding.unspecified')}</button>
          {AGE_GROUPS.map((g) => <button type="button" key={g} className={s.genre} aria-pressed={ageGroup === g} onClick={() => setAgeGroup(g)}>{t(`onboarding.ages.${g}`)}</button>)}
        </div>
      </section>
      <section aria-label={t('onboarding.artists')}>
        <h2 className={s.label}>{t('onboarding.artists')}</h2>
        <div className={s.artists}>
          {options.artists.map((a) => {
            const on = artists.has(a.id);
            return (
              <button
                key={a.id}
                type="button"
                className={cx(s.artist, on && s.on)}
                aria-pressed={on}
                onClick={() => toggle(setArtists, a.id)}
              >
                <span className={s.avatar}>
                  <Cover album={{ id: a.id, cover_url: a.cover_url, cover_colors: a.cover_colors }} size={96} round />
                  {on && (
                    <span className={s.check}>
                      <Icon src={checkIcon} size={22} />
                    </span>
                  )}
                </span>
                <span className={s.name}>{a.name}</span>
              </button>
            );
          })}
        </div>
      </section>

      {options.genres.length > 0 && (
        <section aria-label={t('onboarding.genres')}>
          <h2 className={s.label}>{t('onboarding.genres')}</h2>
          <div className={s.genres}>
            {options.genres.map((g) => (
              <button
                key={g.name}
                type="button"
                className={s.genre}
                aria-pressed={genres.has(g.name)}
                onClick={() => toggle(setGenres, g.name)}
              >
                {g.name}
              </button>
            ))}
          </div>
        </section>
      )}

      <FormError>{save.error ? errorText(save.error) : null}</FormError>
      <div className={s.actions}>
        <Button variant="ghost" disabled={save.isPending} busy={save.isPending && save.variables} onClick={() => editing ? onDone() : save.mutate(true)}>
          {t(editing ? 'form.cancel' : 'onboarding.skip')}
        </Button>
        <Button variant="primary" busy={save.isPending && !save.variables} disabled={!enough || save.isPending} onClick={() => save.mutate(false)}>
          {enough ? t(editing ? 'settings.save' : 'onboarding.done') : t('onboarding.pick_more', { count: MIN_ARTISTS - artists.size })}
        </Button>
      </div>
    </div>
  );
}