import { useQueryClient } from '@tanstack/react-query';
import { Link } from '@tanstack/react-router';
import { useEffect, useRef, useState, useSyncExternalStore, type DragEvent } from 'react';
import { useTranslation } from 'react-i18next';

import { useSession } from '../../app/session';
import { AUDIO_EXTENSIONS, fromDrop, fromInput, needsFormatAttention } from '../../features/uploads/files';
import { uploaderFor, type UploadItem } from '../../features/uploads/uploader';
import { useErrorText } from '../../shared/lib/errors';
import { formatBytes } from '../../shared/lib/format';
import { closeIcon, folderIcon, musicIcon } from '../../shared/ui/icons';
import { Button, cx, FormError, Icon } from '../../shared/ui/ui';
import s from '../page.module.css';
import { QuotaMeter, useUploadQuota } from './common';
import u from './uploads.module.css';

const ACCEPT = [...AUDIO_EXTENSIONS, 'jpg', 'jpeg', 'png', 'webp'].map((e) => `.${e}`).join(',');

/**
 * «Предложить треки» (docs/uploads.md#5): перетащить файлы или папки → SHA-256 в воркере → предпроверка дублей →
 * резерв места → загрузка по tus с докачкой. Дубли отсеиваются до загрузки и не тратят квоту.
 */
export function SuggestPage() {
  const { t, i18n } = useTranslation(['admin', 'common']);
  const session = useSession();
  const queryClient = useQueryClient();
  const errorText = useErrorText();
  const uploader = uploaderFor(session);
  const st = useSyncExternalStore(uploader.subscribe, uploader.getState);
  const quota = useUploadQuota();
  const [drag, setDrag] = useState(false);
  const [comment, setComment] = useState('');
  const filesRef = useRef<HTMLInputElement>(null);
  const dirRef = useRef<HTMLInputElement>(null);

  // webkitdirectory нет в типах React — ставим атрибут напрямую.
  useEffect(() => {
    dirRef.current?.setAttribute('webkitdirectory', '');
  }, []);

  const ready = st.items.filter((it) => it.stage === 'ready');
  const readyBytes = ready.reduce((n, it) => n + it.size, 0);
  const hashing = st.items.some((it) => it.stage === 'hashing' || it.stage === 'checking');
  const finished = !st.busy && st.batchId !== null && !ready.length;
  const resume = st.items.filter((it) => it.stage === 'resume').length;
  const failedUploads = st.items.filter((it) => it.stage === 'error' && it.tusUrl).length;
  const uploaded = st.items.filter((it) => it.stage === 'done').length;
  const free = quota.data ? Math.max(quota.data.limit_bytes - quota.data.used_bytes, 0) : null;
  const fmt = (n: number) => formatBytes(n, i18n.language);

  const onDrop = async (e: DragEvent) => {
    e.preventDefault();
    setDrag(false);
    uploader.add(await fromDrop(e.dataTransfer));
  };
  const start = async () => {
    await uploader.start(comment);
    setComment('');
    await queryClient.invalidateQueries({ queryKey: ['upload-quota'] });
    await queryClient.invalidateQueries({ queryKey: ['my-uploads'] });
  };

  return (
    <div className={s.page}>
      <div className={s.head}>
        <div>
          <h1>{t('uploads.suggest_title')}</h1>
          <p className={s.subtitle}>{t('uploads.suggest_subtitle')}</p>
        </div>
        <QuotaMeter />
      </div>

      <div
        className={cx(u.drop, drag && u.dropActive)}
        onDragOver={(e) => {
          e.preventDefault();
          setDrag(true);
        }}
        onDragLeave={() => setDrag(false)}
        onDrop={(e) => void onDrop(e)}
      >
        <Icon src={musicIcon} size={36} />
        <div className={u.dropTitle}>{t('uploads.drop_title')}</div>
        <p className={u.formatWarn}>{t('uploads.drop_hint')}</p>
        <div className={s.note}>{t('uploads.drop_folders')}</div>
        <div className={s.note}>{t('uploads.cover_hint')}</div>
        <div className={u.dropActions}>
          <Button disabled={st.busy} onClick={() => filesRef.current?.click()}>
            {t('uploads.pick_files')}
          </Button>
          <Button icon={folderIcon} disabled={st.busy} onClick={() => dirRef.current?.click()}>
            {t('uploads.pick_folder')}
          </Button>
        </div>
        <input
          ref={filesRef}
          className={u.hiddenInput}
          type="file"
          multiple
          accept={ACCEPT}
          onChange={(e) => {
            const picked = fromInput(e.target.files);
            if (uploader.getState().items.some((it) => it.stage === 'resume')) void uploader.continueWith(picked);
            else uploader.add(picked);
            e.target.value = '';
          }}
        />
        <input
          ref={dirRef}
          className={u.hiddenInput}
          type="file"
          multiple
          onChange={(e) => {
            const picked = fromInput(e.target.files);
            if (uploader.getState().items.some((it) => it.stage === 'resume')) void uploader.continueWith(picked);
            else uploader.add(picked);
            e.target.value = '';
          }}
        />
      </div>

      {resume > 0 && (
        <section className={s.section}>
          <p>{t('uploads.resume_hint', { count: resume })}</p>
          <Button onClick={() => filesRef.current?.click()}>{t('uploads.resume_pick')}</Button>
        </section>
      )}
      {st.skipped > 0 && <p className={s.note}>{t('uploads.skipped', { count: st.skipped })}</p>}

      {st.items.length > 0 && (
        <div className={u.files} aria-label={t('uploads.files')}>
          {st.items.map((it) => (
            <FileRow key={it.id} item={it} locked={st.busy || finished} retryDisabled={!uploader.canRetryFailed} onRetry={() => void uploader.retryFailed(it.id)} onRemove={() => uploader.remove(it.id)} />
          ))}
        </div>
      )}

      {st.items.length > 0 && !finished && (
        <section className={s.section}>
          <label className={s.sessions}>
            <span>{t('uploads.comment')}</span>
            <textarea
              className={u.textarea}
              value={comment}
              disabled={st.busy}
              maxLength={1000}
              placeholder={t('uploads.comment_hint')}
              onChange={(e) => setComment(e.target.value)}
            />
          </label>
          {free !== null && readyBytes > free && (
            <p className={u.warn}>{t('uploads.not_enough_space', { need: fmt(readyBytes), free: fmt(free) })}</p>
          )}
          <div className={s.toolbar}>
            <Button variant="ghost" disabled={st.busy} onClick={() => uploader.clear()}>
              {t('uploads.clear')}
            </Button>
            <span style={{ flex: 1 }} />
            <Button variant="primary" busy={st.busy} disabled={hashing || !ready.length} onClick={() => void start()}>
              {st.busy
                ? t('uploads.uploading_now')
                : hashing
                  ? t('uploads.hashing_wait')
                  : t('uploads.send', { count: ready.length, size: fmt(readyBytes) })}
            </Button>
          </div>
        </section>
      )}

      {finished && (
        <section className={s.section} role="status">
          {uploaded > 0 && <p className={s.ok}>{t('uploads.sent', { count: uploaded })}</p>}
          {failedUploads > 0 && <p className={u.bad}>{t('uploads.failed_some', { count: failedUploads })}</p>}
          <div className={s.toolbar}>
            {failedUploads > 0 && (
              <Button variant="primary" onClick={() => void uploader.retryFailed()}>
                {t('uploads.retry_failed')}
              </Button>
            )}
            <Link to="/uploads/mine" className={s.more}>
              {t('uploads.go_mine')}
            </Link>
            <span style={{ flex: 1 }} />
            <Button onClick={() => uploader.clear()}>{t('uploads.more')}</Button>
          </div>
        </section>
      )}
      <FormError>{st.error ? errorText(st.error) : null}</FormError>
    </div>
  );
}

function FileRow({ item, locked, retryDisabled, onRetry, onRemove }: {
  item: UploadItem;
  locked: boolean;
  retryDisabled: boolean;
  onRetry: () => void;
  onRemove: () => void;
}) {
  const { t, i18n } = useTranslation(['admin', 'errors']);
  const tr = t as unknown as (k: string) => string;
  const showProgress = item.stage === 'hashing' || item.stage === 'uploading';
  let note: { text: string; cls?: string } | null = null;
  switch (item.stage) {
    case 'duplicate':
      note = { text: t('uploads.dup_found'), cls: u.sub };
      break;
    case 'too_large':
      note = { text: tr('errors:uploads.too_large'), cls: u.bad };
      break;
    case 'rejected':
      note = { text: tr(`errors:${item.code ?? 'uploads.duplicate'}`), cls: u.bad };
      break;
    case 'error':
      note = { text: item.code === 'uploads.storage_full' ? tr('errors:uploads.storage_full') : t('uploads.file_error', { message: item.message ?? '' }), cls: u.bad };
      break;
    case 'ready':
      if (item.possibleDuplicate) note = { text: t('uploads.possible_dup'), cls: u.warn };
      break;
  }
  return (
    <div className={u.file}>
      <div className={u.fileName}>
        <span className={u.path} title={item.relPath}>
          {item.relPath}
        </span>
        <span className={u.sub}>
          {t(`uploads.stage.${item.stage}`)}
          {showProgress && ` · ${Math.round(item.progress * 100)}%`}
        </span>
        {showProgress && (
          <div className={u.progress}>
            <span style={{ width: `${item.progress * 100}%` }} />
          </div>
        )}
        {needsFormatAttention(null, item.relPath) && <span className={u.warn}>{t('uploads.format_attention')}</span>}
        {item.coverName && <span className={u.sub}>{t(item.coverName === 'embedded-cover' ? 'uploads.cover_embedded' : 'uploads.cover_found', { name: item.coverName })}</span>}
        {note && <span className={note.cls}>{note.text}</span>}
      </div>
      <span className={u.size}>{formatBytes(item.size, i18n.language)}</span>
      {item.stage === 'error' && item.tusUrl && item.file ? (
        <Button variant="secondary" disabled={retryDisabled} aria-label={t('uploads.retry_file', { name: item.relPath })} onClick={onRetry}>
          {t('uploads.retry')}
        </Button>
      ) : locked ? (
        <span />
      ) : (
        <Button variant="ghost" aria-label={t('uploads.remove', { name: item.relPath })} onClick={onRemove}>
          <Icon src={closeIcon} size={18} />
        </Button>
      )}
    </div>
  );
}