function createTodayProgress({ storage, getLogin = () => '', admit, makeId = () =>
  globalThis.crypto?.randomUUID?.() || String(Date.now()) + '-' + Math.random().toString(16).slice(2),
maxLength = 2000, maxItems = 20 }) {
  const prefix = 'stackchain.today-progress.v1.';
  const login = () => String(getLogin() || '').trim().toLowerCase();
  const storageKey = () => login() ? prefix + encodeURIComponent(login()) : '';
  const validIdentity = identity => typeof identity === 'string' && identity.length > 0 && identity.length <= 500;
  const validRecord = record => record && typeof record.body === 'string' && record.body.length > 0 &&
    record.body.length <= maxLength && typeof record.operation_id === 'string' && record.operation_id.length > 0 &&
    record.operation_id.length <= 128;

  function read() {
    const key = storageKey();
    if (!storage || !key) return {};
    try {
      const saved = JSON.parse(storage.getItem(key) || 'null');
      if (!saved || saved.version !== 1 || !saved.drafts || typeof saved.drafts !== 'object' ||
          Array.isArray(saved.drafts)) return {};
      const entries = Object.entries(saved.drafts).filter(([identity, record]) =>
        validIdentity(identity) && validRecord(record)
      ).slice(0, maxItems);
      return Object.fromEntries(entries);
    } catch (_error) {
      return {};
    }
  }

  function write(drafts) {
    const key = storageKey();
    if (!storage || !key) return false;
    try {
      if (Object.keys(drafts).length) storage.setItem(key, JSON.stringify({ version:1, drafts }));
      else storage.removeItem(key);
      return true;
    } catch (_error) {
      return false;
    }
  }

  function load(identity) {
    if (!validIdentity(identity)) return '';
    return read()[identity]?.body || '';
  }

  function save(identity, value) {
    if (!validIdentity(identity) || !storageKey()) return false;
    const body = String(value || '').trim();
    if (body.length > maxLength) return false;
    const drafts = read();
    if (!body) {
      delete drafts[identity];
      return write(drafts);
    }
    if (!drafts[identity] && Object.keys(drafts).length >= maxItems) return false;
    const previous = drafts[identity];
    drafts[identity] = {
      body,
      operation_id: previous?.body === body ? previous.operation_id : String(makeId()).slice(0, 128),
    };
    return write(drafts);
  }

  function validTarget(target) {
    return target && ['issue', 'pull'].includes(target.kind) && validIdentity(target.identity) &&
      typeof target.repository === 'string' && target.repository.length > 0 && target.repository.length <= 200 &&
      Number.isInteger(target.number) && target.number > 0;
  }

  async function post(target, value) {
    if (!validTarget(target)) throw new Error('An active Today issue or pull request is required.');
    if (value !== undefined && !save(target.identity, value)) throw new Error('Progress update could not be saved on this device.');
    const record = read()[target.identity];
    if (!record) throw new Error('Write a progress update before posting.');
    if (typeof admit !== 'function') throw new Error('Progress update delivery is unavailable.');
    const admission = await admit({
      kind:target.kind + '-comment', repository:target.repository, number:target.number,
      body:record.body, operationId:record.operation_id,
    });
    const drafts = read();
    if (drafts[target.identity]?.operation_id === record.operation_id) {
      delete drafts[target.identity];
      write(drafts);
    }
    return admission;
  }

  return { load, save, discard:identity => save(identity, ''), post };
}

function createTodayProgressView({ progress, currentTarget, qs, announce = () => {}, onAdmitted = () => {} }) {
  const sheet = qs('#today-progress-sheet');
  const body = qs('#today-progress-body');
  const status = qs('#today-progress-status');
  const launcher = qs('[data-mobile-today-update]');
  let openedTarget = null;

  const update = () => { launcher.hidden = !currentTarget(); };
  const checkpoint = () => {
    if (!openedTarget) return false;
    if (progress.save(openedTarget.identity, body.value)) return true;
    status.textContent = 'Update must be 2,000 characters or fewer and device storage must be available.';
    return false;
  };
  const close = () => {
    if (sheet.open) sheet.close();
    openedTarget = null;
  };

  launcher.addEventListener('click', () => {
    const target = currentTarget();
    if (!target) return;
    openedTarget = target;
    qs('#today-progress-target').textContent = target.label + (target.title ? ' · ' + target.title : '');
    body.value = progress.load(target.identity);
    status.textContent = '';
    sheet.showModal();
    body.focus();
  });
  qs('#cancel-today-progress').addEventListener('click', () => {
    if (checkpoint()) close();
  });
  sheet.addEventListener('cancel', event => {
    event.preventDefault();
    if (checkpoint()) close();
  });
  qs('#save-today-progress').addEventListener('click', () => {
    if (!checkpoint()) return;
    announce('Progress update saved privately to this Today item.');
    close();
  });
  qs('#post-today-progress').addEventListener('click', async () => {
    const target = currentTarget();
    if (!target || target.identity !== openedTarget?.identity) {
      status.textContent = 'The active Today item changed. Close and open its update again.';
      return;
    }
    const button = qs('#post-today-progress');
    button.disabled = true;
    status.textContent = 'Saving for delivery…';
    try {
      const admission = await progress.post(target, body.value);
      onAdmitted(admission);
      announce(admission.background ?
        'Progress update queued for delivery. Today is still on the same item.' :
        'Progress update saved for next launch. Today is still on the same item.');
      close();
    } catch (error) {
      status.textContent = error.message + ' Your update remains on this item; retry.';
      body.focus();
    } finally {
      button.disabled = false;
    }
  });
  update();
  return { update };
}

if (typeof module !== 'undefined' && module.exports) {
  module.exports = createTodayProgress;
  module.exports.createView = createTodayProgressView;
}