function mergeEligibility(detail, reviewState) {
  if (!detail || detail.state !== 'open' || detail.merged) {
    return { allowed: false, reason: 'Pull request is not open' };
  }
  if (detail.draft) return { allowed: false, reason: 'Draft pull requests cannot be merged' };
  if (!detail.mergeable) return { allowed: false, reason: 'Resolve conflicts before merging' };
  if (detail.ci_state !== 'success') {
    const blockers = (detail.checks || []).filter(check =>
      ['failure', 'error', 'pending'].includes(check.state)
    ).map(check => check.name).filter(Boolean).slice(0, 3);
    return { allowed: false, reason: blockers.length ?
      'CI blocked by ' + blockers.join(', ') : 'CI must succeed before merging' };
  }
  if (!detail.head_sha) return { allowed: false, reason: 'Current head is unavailable' };
  const reviewer = (detail.reviewers || []).find(item => item?.blocking);
  if (reviewer?.status === 'waiting') {
    return { allowed: false, reason: 'Waiting for @' + reviewer.login + '’s review' };
  }
  if (reviewer?.status === 'changes_requested') {
    return { allowed: false, reason: '@' + reviewer.login + ' requested changes' };
  }
  if (reviewer?.status === 'outdated') {
    return { allowed: false, reason: '@' + reviewer.login + '’s review is outdated after new commits' };
  }
  if (reviewState && !reviewState.complete) {
    return { allowed: false, reason: 'Review every changed file before merging' };
  }
  return { allowed: true, reason: 'Ready to merge' };
}

function renderReviewerFeedback(reviewer, escapeHtml) {
  const groups = new Map();
  (Array.isArray(reviewer?.comments) ? reviewer.comments : []).forEach(comment => {
    if (!comment?.path || !comment?.body) return;
    if (!groups.has(comment.path)) groups.set(comment.path, []);
    groups.get(comment.path).push(comment);
  });
  const summary = reviewer?.summary ? '<p class="pull-review-feedback-summary">' +
    escapeHtml(reviewer.summary) + '</p>' : '';
  const files = Array.from(groups.entries()).map(([path, comments]) =>
    '<section class="pull-review-feedback-file"><h4>' + escapeHtml(path) + '</h4><ul>' +
    comments.map(comment => '<li>' + escapeHtml(comment.body) +
      (comment.line ? '<small>Line ' + Number(comment.line) + '</small>' : '') + '</li>').join('') +
    '</ul><button type="button" data-review-feedback-file="' + escapeHtml(path) +
    '">View in changes</button></section>'
  ).join('');
  if (!summary && !files) return '';
  const reviewedHead = reviewer?.status === 'outdated' && reviewer?.head_sha ?
    '<p class="small">Reviewed head ' + escapeHtml(reviewer.head_sha.slice(0, 8)) + '</p>' : '';
  return '<details class="pull-review-feedback"><summary>Review feedback</summary>' +
    reviewedHead + summary + files + '</details>';
}

function renderReviewerStatuses(reviewers, escapeHtml) {
  const labels = {
    waiting: 'Waiting for review',
    approved: 'Approved current head',
    changes_requested: 'Changes requested',
    commented: 'Commented',
    outdated: 'Outdated after new commits',
  };
  return (Array.isArray(reviewers) ? reviewers : []).map(reviewer => {
    const status = labels[reviewer?.status] || 'Status unavailable';
    return '<article class="pull-reviewer-status" data-reviewer-status="' +
      escapeHtml(reviewer?.status || 'unknown') + '"><div class="pull-reviewer-status-heading"><strong>@' +
      escapeHtml(reviewer?.login || 'unknown') + '</strong><span>' + escapeHtml(status) + '</span></div>' +
      renderReviewerFeedback(reviewer, escapeHtml) + '</article>';
  }).join('');
}

function renderReviewerPanel(doc, detail, escapeHtml = value => String(value)
  .replaceAll('&', '&amp;').replaceAll('<', '&lt;').replaceAll('>', '&gt;')) {
  const reviewers = Array.isArray(detail?.reviewers) ? detail.reviewers : [];
  doc.querySelector('#pull-reviewer-statuses').innerHTML = renderReviewerStatuses(reviewers, escapeHtml);
  doc.querySelectorAll('[data-review-feedback-file]').forEach(button => {
    button.addEventListener('click', () => focusPullFile(doc, button.dataset.reviewFeedbackFile));
  });
  doc.querySelector('#pull-reviewer-status').textContent = reviewers.length ?
    reviewers.length + ' reviewer status' + (reviewers.length === 1 ? '' : 'es') + ' for this pull request.' :
    'No review has been requested; existing merge policy is unchanged.';
  doc.querySelector('#request-updated-pull-review').hidden =
    !reviewers.some(reviewer => reviewer.status === 'outdated');
}

function reviewEligibility(detail, reviewState, doc) {
  renderReviewerPanel(doc, detail);
  return mergeEligibility(detail, reviewState);
}

function renderFile(file, index, reviewed, escapeHtml) {
  const filename = escapeHtml(file.filename || 'Unknown file');
  const panelId = 'pull-diff-' + index;
  const lines = (file.diff_lines || []).map(line => {
    const text = String(line);
    const kind = text.startsWith('@@') ? 'hunk' : text.startsWith('+') ? 'added' :
      text.startsWith('-') ? 'removed' : 'context';
    return '<span class="pull-diff-line ' + kind + '">' + escapeHtml(text) + '</span>';
  }).join('');
  const preview = file.diff_available
    ? '<pre class="pull-diff" id="' + panelId + '" hidden>' + lines +
      (file.diff_truncated ? '<span class="pull-diff-note">Preview truncated · open in Gitea for the full diff.</span>' : '') + '</pre>'
    : '<div class="pull-diff-empty" id="' + panelId + '" hidden>' +
      (file.diff_binary ? 'Binary file · preview unavailable.' : 'Diff preview unavailable.') +
      (file.diff_truncated ? ' The response was truncated.' : '') + '</div>';
  return '<article class="pull-file" data-pull-filename="' + filename + '">' +
    '<button type="button" class="pull-file-toggle" aria-expanded="false" aria-controls="' + panelId + '">' +
    '<strong>' + filename + '</strong><span class="small">' + escapeHtml(file.status || 'changed') +
    ' · +' + Number(file.additions || 0) + ' / −' + Number(file.deletions || 0) + '</span></button>' + preview +
    '<button type="button" class="pull-review-file" data-pull-review-file="' + filename +
    '" aria-pressed="' + String(reviewed) + '">' + (reviewed ? 'Reviewed' : 'Mark reviewed') + '</button></article>';
}

function focusPullFile(doc, filename) {
  const article = Array.from(doc.querySelectorAll('#pull-files .pull-file'))
    .find(file => file.dataset.pullFilename === filename);
  const toggle = article?.querySelector('.pull-file-toggle');
  const panel = toggle && doc.getElementById(toggle.getAttribute('aria-controls'));
  if (!toggle || !panel) return false;
  toggle.setAttribute('aria-expanded', 'true');
  panel.hidden = false;
  toggle.scrollIntoView({ block: 'center', behavior: 'smooth' });
  toggle.focus();
  return true;
}

function focusNextUnreviewed(doc, detail, state, controller) {
  if (!detail || !state) return;
  focusPullFile(doc, controller.nextUnreviewed(detail, state));
}

function removeFromSnapshot(data, item) {
  return { ...data, pulls:(data.pulls || []).filter(candidate =>
    candidate.repository !== item.repository || candidate.number !== item.number) };
}

function sameTarget(left, right) {
  return Boolean(left && right && left.repository === right.repository && Number(left.number) === Number(right.number));
}

function ownershipSelectors() {
  return ['#release-pull', '#load-pull-handoff', '#pull-handoff-recipient', '#confirm-pull-handoff'];
}

function renderHandoffCandidates(select, candidates, doc) {
  select.textContent = '';
  const placeholder = doc.createElement('option');
  placeholder.value = '';
  placeholder.textContent = candidates.length ? 'Select a teammate' : 'No eligible teammates';
  select.appendChild(placeholder);
  candidates.forEach(candidate => {
    const option = doc.createElement('option');
    option.value = candidate.login;
    option.textContent = candidate.name + (candidate.name === candidate.login ? '' : ' (@' + candidate.login + ')');
    select.appendChild(option);
  });
  return candidates.length;
}

function ownershipExitMessage(item, action, transitionResult) {
  return item.key + ' ' + action + (transitionResult === 'opened' ?
    '. Next work item opened.' : '. Choose the next ready Today item.');
}

function resetOwnershipControls(doc, item, checkpointed) {
  const qs = selector => doc.querySelector(selector);
  qs('#pull-ownership').open = false;
  qs('#pull-handoff-recipient').innerHTML = '<option value="">Select a teammate</option>';
  qs('#pull-handoff-recipient').disabled = true;
  qs('#confirm-pull-handoff').disabled = true;
  qs('#confirm-pull-handoff').textContent = checkpointed(item) ? 'Hand off & next' : 'Confirm handoff';
  qs('#load-pull-handoff').disabled = false;
  qs('#release-pull').disabled = false;
  qs('#release-pull').textContent = checkpointed(item) ? 'Release & next' : 'Release assignment';
  qs('#pull-handoff-status').textContent = 'Load teammates to transfer ownership.';
  qs('#edit-pull-content').hidden = true;
  qs('#pull-edit-form').hidden = true;
  qs('#pull-edit-status').textContent = '';
}

function resetReviewRequestControls(doc, detail) {
  const qs = selector => doc.querySelector(selector);
  qs('#pull-review-request').open = false;
  qs('#pull-review-request').dataset.headSha = detail?.head_sha || '';
  qs('#pull-review-recipient').innerHTML = '<option value="">Select a teammate</option>';
  qs('#pull-review-recipient').disabled = true;
  qs('#confirm-pull-review').disabled = true;
  qs('#load-pull-reviewers').disabled = !detail?.head_sha;
  qs('#pull-review-request-status').textContent = detail?.head_sha ?
    'Load teammates to request a review.' : 'Load the current pull request before requesting review.';
  qs('#pull-reviewer-status').textContent = 'Reviewer status not loaded.';
  qs('#pull-reviewer-statuses').textContent = '';
  qs('#request-updated-pull-review').hidden = true;
}

function bindReviewRequestControls(doc, controller, getSelected, getDetail) {
  const qs = selector => doc.querySelector(selector);
  const load = qs('#load-pull-reviewers');
  if (load.dataset.reviewRequestBound === 'true') return;
  load.dataset.reviewRequestBound = 'true';
  controller.setReviewDetail = detail => {
    resetReviewRequestControls(doc, detail);
    controller.edit?.setDetail(detail, Boolean(detail?.saved_at));
  };
  resetReviewRequestControls(doc, null);
  qs('#request-updated-pull-review').addEventListener('click', () => {
    qs('#pull-review-request').open = true;
    qs('#pull-review-request').scrollIntoView({ block:'center', behavior:'smooth' });
    load.focus();
  });
  controller.onReviewRequested = result => {
    const detail = getDetail?.();
    if (!detail || result.head_sha !== detail.head_sha) return;
    detail.reviewers = (detail.reviewers || []).filter(reviewer => reviewer.login !== result.reviewer);
    detail.reviewers.push({login:result.reviewer, status:'waiting', head_sha:result.head_sha, blocking:true});
    renderReviewerPanel(doc, detail);
    qs('#pull-merge-state').textContent = 'Waiting for @' + result.reviewer + '’s review';
    qs('#merge-pull').disabled = true;
  };
  load.addEventListener('click', async () => {
    const selected = getSelected();
    if (!selected) return;
    const select = qs('#pull-review-recipient');
    load.disabled = true;
    qs('#pull-review-request-status').textContent = 'Loading eligible reviewers…';
    try {
      const count = renderHandoffCandidates(select, await controller.loadReviewCandidates(selected), doc);
      select.disabled = !count;
      qs('#confirm-pull-review').disabled = true;
      qs('#pull-review-request-status').textContent = count ?
        'Choose a teammate to review the current head.' : 'No eligible reviewers were found.';
      if (count) select.focus();
      else load.disabled = false;
    } catch (error) {
      qs('#pull-review-request-status').textContent = error.message + ' Retry loading reviewers.';
      load.disabled = false;
      load.focus();
    }
  });
  qs('#pull-review-recipient').addEventListener('change', event => {
    qs('#confirm-pull-review').disabled = !event.target.value;
  });
  qs('#confirm-pull-review').addEventListener('click', async () => {
    const selected = getSelected();
    const detail = { head_sha: qs('#pull-review-request').dataset.headSha };
    const reviewer = qs('#pull-review-recipient').value;
    if (!selected || !detail?.head_sha || !reviewer ||
        !globalThis.confirm('Request review of ' + selected.key + ' at ' + detail.head_sha.slice(0, 8) + ' from @' + reviewer + '?')) return;
    const button = qs('#confirm-pull-review');
    button.disabled = true;
    qs('#pull-review-request-status').textContent = 'Requesting review…';
    try {
      await controller.requestReview(selected, reviewer, detail.head_sha);
      qs('#pull-review-request-status').textContent = 'Review requested from @' + reviewer + '.';
    } catch (error) {
      qs('#pull-review-request-status').textContent = error.message + ' Selection kept; retry the request.';
      button.disabled = false;
      button.focus();
    }
  });
}

function bindContextEditor(doc, controller, getSelected, getDetail, getLogin) {
  const qs = selector => doc.querySelector(selector);
  const form = qs('#pull-edit-form');
  const controls = () => form.querySelectorAll('input,textarea,button');
  const draft = () => ({
    title:qs('#pull-edit-title').value.trim(), body:qs('#pull-edit-body').value,
    expectedHeadSha:getDetail()?.head_sha || '',
  });
  qs('#edit-pull-content').addEventListener('click', () => {
    const item = getSelected(), detail = getDetail();
    if (!item || !detail) return;
    const saved = controller.loadEditDraft(item) || {
      title:detail.title || '', body:detail.body || '', expectedHeadSha:detail.head_sha || '',
    };
    qs('#pull-edit-title').value = saved.title;
    qs('#pull-edit-body').value = saved.body;
    form.hidden = false;
    qs('#pull-edit-status').textContent = '';
    qs('#pull-edit-title').focus();
  });
  qs('#cancel-pull-edit').addEventListener('click', () => {
    form.hidden = true;
    qs('#edit-pull-content').focus();
  });
  ['#pull-edit-title', '#pull-edit-body'].forEach(selector => qs(selector).addEventListener('input', () => {
    const item = getSelected();
    if (item && getDetail()) controller.saveEditDraft(item, draft());
  }));
  form.addEventListener('submit', async event => {
    event.preventDefault();
    const item = getSelected(), update = draft();
    if (!item || !getDetail()) return;
    if (!update.title) {
      qs('#pull-edit-status').textContent = 'Title is required.';
      qs('#pull-edit-title').focus();
      return;
    }
    controls().forEach(control => { control.disabled = true; });
    qs('#pull-edit-status').textContent = 'Saving review context…';
    try {
      const result = await controller.updateContent(item, update);
      if (getSelected() !== item) return;
      const detail = getDetail();
      Object.assign(detail, result);
      item.title = result.title;
      qs('#pull-sheet-title').textContent = result.title;
      qs('#pull-sheet-body').innerHTML = renderMarkdown(result.body || 'No description provided.');
      controller.setReviewDetail(detail);
      qs('#pull-sheet-status').textContent = 'Review context updated · ready to request review';
      form.hidden = true;
      qs('#pull-edit-status').textContent = '';
      qs('#edit-pull-content').focus();
    } catch (error) {
      qs('#pull-edit-status').textContent = error.message + ' Your change is still here; retry.';
      qs('#pull-edit-title').focus();
    } finally {
      controls().forEach(control => { control.disabled = false; });
    }
  });
  return {
    reset() {
      qs('#edit-pull-content').hidden = true;
      form.hidden = true;
      qs('#pull-edit-status').textContent = '';
    },
    setDetail(detail, offline = false) {
      const editable = !offline && detail?.state === 'open' && detail.author === getLogin();
      qs('#edit-pull-content').hidden = !editable;
    },
  };
}

function bindOwnershipControls(doc, controller, getSelected, finish, getDetail, getLogin) {
  bindReviewRequestControls(doc, controller, getSelected, getDetail);
  controller.edit = bindContextEditor(doc, controller, getSelected, getDetail, getLogin);
  const qs = selector => doc.querySelector(selector);
  const load = qs('#load-pull-handoff');
  if (load.dataset.ownershipBound === 'true') return;
  load.dataset.ownershipBound = 'true';
  load.addEventListener('click', async () => {
    const selected = getSelected();
    if (!selected) return;
    const select = qs('#pull-handoff-recipient');
    load.disabled = true;
    qs('#pull-handoff-status').textContent = 'Loading eligible teammates…';
    try {
      const count = renderHandoffCandidates(select, await controller.loadHandoffCandidates(selected), doc);
      select.disabled = !count;
      qs('#confirm-pull-handoff').disabled = true;
      qs('#pull-handoff-status').textContent = count ?
        'Choose who should own this pull request next.' : 'No other eligible assignees were found.';
      if (count) select.focus();
    } catch (error) {
      qs('#pull-handoff-status').textContent = error.message + ' Retry loading teammates.';
      load.disabled = false;
      load.focus();
    }
  });
  qs('#pull-handoff-recipient').addEventListener('change', event => {
    qs('#confirm-pull-handoff').disabled = !event.target.value;
  });
  qs('#confirm-pull-handoff').addEventListener('click', async () => {
    const selected = getSelected();
    const recipient = qs('#pull-handoff-recipient').value;
    if (!selected || !recipient || !globalThis.confirm('Hand off ' + selected.key + ' to @' + recipient + '?')) return;
    const button = qs('#confirm-pull-handoff');
    button.disabled = true;
    qs('#pull-handoff-status').textContent = 'Confirming handoff…';
    try {
      await controller.handoff(selected, recipient);
      const transition = await finish(selected);
      qs('#my-work-action-status').textContent = transition === false ?
        selected.key + ' handed off to @' + recipient + '.' :
        ownershipExitMessage(selected, 'handed off to @' + recipient, transition);
    } catch (error) {
      qs('#pull-handoff-status').textContent = error.message + ' The pull request remains in My Work; retry.';
      button.disabled = false;
      button.focus();
    }
  });
  qs('#release-pull').addEventListener('click', async () => {
    const selected = getSelected();
    if (!selected || !globalThis.confirm('Release ' + selected.key + ' from your My Work?')) return;
    const button = qs('#release-pull');
    button.disabled = true;
    qs('#pull-sheet-status').textContent = 'Releasing assignment…';
    try {
      await controller.release(selected);
      const transition = await finish(selected);
      qs('#my-work-action-status').textContent = transition === false ?
        selected.key + ' released.' : ownershipExitMessage(selected, 'released', transition);
    } catch (error) {
      qs('#pull-sheet-status').textContent = error.message + ' The pull request remains in My Work; retry.';
      button.disabled = false;
      button.focus();
    }
  });
}

function createPullSheet({ fetchJson, storage, createConversationPager = globalThis.createConversationPager, createOperationId = () => globalThis.crypto?.randomUUID?.() || String(Date.now()) + '-' + Math.random() }) {
  let commentRequest = null;
  let mergeRequest = null;
  let checkRequest = null;
  let ownershipRequest = null;
  let candidateRequest = null;
  let reviewCandidateRequest = null;
  let reviewRequestMutation = null;
  let editRequest = null;
  const reviewRequests = new Map();
  const reviewCache = new Map();
  const pathFor = item => 'api/v1/repos/' + String(item.repository || '').split('/')
    .map(encodeURIComponent).join('/') + '/pulls/' + encodeURIComponent(item.number);
  const draftKey = item => 'stackchain.pull-comment.v1:' + item.repository + '#' + item.number;
  const operationKey = item => draftKey(item) + ':operation';
  const editDraftKey = item => 'stackchain.pull-edit.v1:' + item.repository + '#' + item.number;
  const reviewKey = (item, detail) => 'stackchain.pull-review.v1:' + item.repository + '#' + item.number + ':' + detail.head_sha;
  const fileNames = detail => (detail?.files || []).map(file => file.filename).filter(Boolean);

  function reviewState(item, detail) {
    const files = fileNames(detail);
    let saved = [];
    try {
      const value = JSON.parse(storage?.getItem(reviewKey(item, detail)) || '[]');
      if (Array.isArray(value)) saved = value;
    } catch (_error) { /* Corrupt progress safely starts over. */ }
    const reviewed = files.filter(filename => saved.includes(filename));
    return { reviewed, total: files.length, complete: reviewed.length === files.length };
  }

  return {
    load(item) {
      return fetchJson(pathFor(item) + '/detail', { headers: { Accept: 'application/json' } });
    },
    loadReview(item, headSha, { refresh = false } = {}) {
      const key = item.repository + '#' + item.number + ':' + headSha;
      if (!refresh && reviewCache.has(key)) return Promise.resolve(reviewCache.get(key));
      if (reviewRequests.has(key)) return reviewRequests.get(key);
      const request = fetchJson(pathFor(item) + '/review-data', {
        headers: { Accept: 'application/json' },
      }).then(detail => {
        const confirmedKey = item.repository + '#' + item.number + ':' + detail.head_sha;
        reviewCache.set(confirmedKey, detail);
        return detail;
      }).finally(() => reviewRequests.delete(key));
      reviewRequests.set(key, request);
      return request;
    },
    loadChecks(item) {
      if (checkRequest) return checkRequest;
      checkRequest = fetchJson(pathFor(item) + '/checks', {
        headers: { Accept: 'application/json' },
      }).finally(() => { checkRequest = null; });
      return checkRequest;
    },
    loadHandoffCandidates(item) {
      if (candidateRequest) return candidateRequest;
      candidateRequest = fetchJson(pathFor(item) + '/handoff-candidates', {
        headers: { Accept: 'application/json' },
      }).finally(() => { candidateRequest = null; });
      return candidateRequest;
    },
    loadReviewCandidates(item) {
      if (reviewCandidateRequest) return reviewCandidateRequest;
      reviewCandidateRequest = fetchJson(pathFor(item) + '/review-candidates', {
        headers: { Accept: 'application/json' },
      }).finally(() => { reviewCandidateRequest = null; });
      return reviewCandidateRequest;
    },
    requestReview(item, reviewer, expectedHeadSha) {
      if (reviewRequestMutation) return reviewRequestMutation;
      reviewRequestMutation = fetchJson(pathFor(item) + '/request-review', {
        method: 'POST',
        headers: { Accept: 'application/json', 'Content-Type': 'application/json' },
        body: JSON.stringify({ reviewer, expected_head_sha: expectedHeadSha }),
      }).then(result => {
        this.onReviewRequested?.(result);
        return result;
      }).finally(() => { reviewRequestMutation = null; });
      return reviewRequestMutation;
    },
    loadEditDraft(item) {
      try {
        const value = JSON.parse(storage?.getItem(editDraftKey(item)) || 'null');
        return value && typeof value.title === 'string' && typeof value.body === 'string' &&
          typeof value.expectedHeadSha === 'string' ? value : null;
      } catch (_error) { return null; }
    },
    saveEditDraft(item, draft) {
      try { storage?.setItem(editDraftKey(item), JSON.stringify(draft)); }
      catch (_error) { /* The edit fields remain the fallback. */ }
    },
    updateContent(item, draft) {
      if (editRequest) return editRequest;
      this.saveEditDraft(item, draft);
      editRequest = fetchJson(pathFor(item) + '/content', {
        method: 'PATCH',
        headers: { Accept: 'application/json', 'Content-Type': 'application/json' },
        body: JSON.stringify({
          title: draft.title,
          body: draft.body,
          expected_head_sha: draft.expectedHeadSha,
        }),
      }).then(result => {
        if (result?.number !== item.number || result?.title !== draft.title ||
            result?.body !== draft.body || result?.head_sha !== draft.expectedHeadSha) {
          throw new Error('Pull request update was not confirmed.');
        }
        try { storage?.removeItem(editDraftKey(item)); }
        catch (_error) { /* Confirmed upstream content is authoritative. */ }
        return result;
      }).finally(() => { editRequest = null; });
      return editRequest;
    },
    handoff(item, recipient) {
      if (ownershipRequest) return ownershipRequest;
      ownershipRequest = fetchJson(pathFor(item) + '/handoff', {
        method: 'PATCH',
        headers: { Accept: 'application/json', 'Content-Type': 'application/json' },
        body: JSON.stringify({ recipient }),
      }).finally(() => { ownershipRequest = null; });
      return ownershipRequest;
    },
    release(item) {
      if (ownershipRequest) return ownershipRequest;
      ownershipRequest = fetchJson(pathFor(item) + '/release', {
        method: 'PATCH', headers: { Accept: 'application/json' },
      }).finally(() => { ownershipRequest = null; });
      return ownershipRequest;
    },
    conversation(item, initialPage) {
      const pager = createConversationPager({
        loadPage: page => fetchJson(pathFor(item) + '/comments?page=' + encodeURIComponent(page) + '&limit=20', {
          headers: { Accept: 'application/json' },
        }),
      });
      pager.reset(initialPage || { comments: [], page: 1, older_page: null, total: 0 });
      return pager;
    },
    reviewState,
    toggleReviewed(item, detail, filename) {
      const state = reviewState(item, detail);
      const reviewed = new Set(state.reviewed);
      if (reviewed.has(filename)) reviewed.delete(filename);
      else if (fileNames(detail).includes(filename)) reviewed.add(filename);
      try { storage?.setItem(reviewKey(item, detail), JSON.stringify(Array.from(reviewed))); }
      catch (_error) { /* In-memory controls still work for this render. */ }
      return reviewState(item, detail);
    },
    nextUnreviewed(detail, state) {
      return fileNames(detail).find(filename => !state.reviewed.includes(filename)) || null;
    },
    loadDraft(item) {
      try { return storage?.getItem(draftKey(item)) || ''; }
      catch (_error) { return ''; }
    },
    saveDraft(item, body) {
      try {
        if ((storage?.getItem(draftKey(item)) || '') !== body) storage?.removeItem(operationKey(item));
        storage?.setItem(draftKey(item), body);
      }
      catch (_error) { /* The textarea remains the fallback. */ }
    },
    comment(item, body) {
      if (commentRequest) return commentRequest;
      this.saveDraft(item, body);
      let operationId;
      try {
        operationId = storage?.getItem(operationKey(item)) || String(createOperationId()).slice(0, 128);
        storage?.setItem(operationKey(item), operationId);
      } catch (_error) { operationId = String(createOperationId()).slice(0, 128); }
      commentRequest = fetchJson(pathFor(item) + '/comments', {
        method: 'POST',
        headers: { Accept: 'application/json', 'Content-Type': 'application/json', 'Idempotency-Key': operationId },
        body: JSON.stringify({ body }),
      }).then(result => {
        try { storage?.removeItem(draftKey(item)); }
        catch (_error) { /* The upstream comment is authoritative. */ }
        try { storage?.removeItem(operationKey(item)); }
        catch (_error) { /* A confirmed result no longer needs replay identity. */ }
        return result;
      }).finally(() => { commentRequest = null; });
      return commentRequest;
    },
    merge(item, expectedHeadSha) {
      if (mergeRequest) return mergeRequest;
      mergeRequest = fetchJson(pathFor(item) + '/merge', {
        method: 'POST',
        headers: { Accept: 'application/json', 'Content-Type': 'application/json' },
        body: JSON.stringify({ expected_head_sha: expectedHeadSha }),
      }).then(result => {
        if (!result?.merged) {
          throw new Error(result?.confirmation_pending && result?.error
            ? result.error
            : 'Pull request merge was not confirmed.');
        }
        return result;
      }).finally(() => { mergeRequest = null; });
      return mergeRequest;
    },
  };
}

createPullSheet.mergeEligibility = mergeEligibility;
createPullSheet.review = reviewEligibility;
createPullSheet.renderReviewerStatuses = renderReviewerStatuses;
createPullSheet.renderFile = renderFile;
createPullSheet.focusNextUnreviewed = focusNextUnreviewed;
createPullSheet.removeFromSnapshot = removeFromSnapshot;
createPullSheet.sameTarget = sameTarget;
createPullSheet.ownershipSelectors = ownershipSelectors;
createPullSheet.renderHandoffCandidates = renderHandoffCandidates;
createPullSheet.ownershipExitMessage = ownershipExitMessage;
createPullSheet.resetOwnershipControls = resetOwnershipControls;
createPullSheet.bindOwnershipControls = bindOwnershipControls;
createPullSheet.bindContextEditor = bindContextEditor;
createPullSheet.resetReviewRequestControls = resetReviewRequestControls;
createPullSheet.bindReviewRequestControls = bindReviewRequestControls;
if (typeof module !== 'undefined' && module.exports) module.exports = createPullSheet;