(function (root, factory) {
  const createSearchPreview = factory();
  if (typeof module === 'object' && module.exports) module.exports = createSearchPreview;
  if (root) {
    root.createSearchPreview = createSearchPreview;
    root.safeSearchUrl = value => {
      try {
        const url = new URL(value);
        return ['http:', 'https:'].includes(url.protocol) ? url.href : '';
      } catch (_) { return ''; }
    };
  }
})(typeof globalThis !== 'undefined' ? globalThis : this, function () {
  return function createSearchPreview({ fetchJson, mutate, share, session, getSession, loadMore, onNavigate, navigationRoot, onState }) {
    if (Array.isArray(session)) {
      getSession = session[0];
      loadMore = () => session[1].loadMore();
      onNavigate = session[2];
      navigationRoot = document;
    }
    let generation = 0;
    let current = null;
    let mutationRequest = null;
    let shareRequest = null;
    let moveRequest = null;

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

    function navigation(item) {
      const session = typeof getSession === 'function' ? getSession() : null;
      const items = Array.isArray(session?.items) ? session.items : [];
      const index = items.findIndex(candidate => sameItem(candidate, item));
      if (index < 0) return null;
      return {
        position:index + 1,
        total:items.length,
        hasPrevious:index > 0,
        hasNext:index < items.length - 1 || session.more === true,
      };
    }

    function publish(state) {
      const position = navigation(state.item || current);
      if (navigationRoot) {
        const bar = navigationRoot.querySelector('.search-preview-navigation');
        bar.hidden = !position;
        if (position) {
          navigationRoot.querySelector('#search-preview-position').textContent = position.position + ' of ' + position.total;
          navigationRoot.querySelector('#previous-search-result').disabled = !position.hasPrevious;
          navigationRoot.querySelector('#next-search-result').disabled = !position.hasNext;
        }
      }
      onState(position ? { ...state, navigation:position } : state);
      if (state.complete && navigationRoot) {
        navigationRoot.querySelector('#search-preview-status').textContent = 'Search pass complete.';
      }
    }

    function run(action, pending, success, detail) {
      if (mutationRequest) return mutationRequest;
      publish({ status: pending, item: current, detail });
      mutationRequest = mutate(detail, action).then(result => {
        publish({ status: success, item: current, detail, result });
        return result;
      }).catch(error => {
        publish({ status: 'ready', item: current, detail, error });
        throw error;
      }).finally(() => { mutationRequest = null; });
      return mutationRequest;
    }

    const api = {
      open(item) {
        generation += 1;
        const requestGeneration = generation;
        current = { ...item };
        publish({ status: 'loading', item: current });
        return fetchJson(current).then(detail => {
          if (requestGeneration === generation) {
            current = { ...current, ...detail };
            publish({ status: 'ready', item: current, detail });
          }
          return detail;
        }).catch(error => {
          if (requestGeneration === generation) {
            publish({ status: 'error', item: current, error });
          }
          throw error;
        });
      },
      close() {
        generation += 1;
        current = null;
        onState({ status: 'closed' });
      },
      previous() {
        const session = typeof getSession === 'function' ? getSession() : null;
        const items = Array.isArray(session?.items) ? session.items : [];
        const index = items.findIndex(item => sameItem(item, current));
        if (index <= 0) return Promise.resolve(current);
        const item = items[index - 1];
        if (typeof onNavigate === 'function') onNavigate(item);
        return api.open(item);
      },
      next() {
        if (moveRequest) return moveRequest;
        moveRequest = (async () => {
          let session = typeof getSession === 'function' ? getSession() : null;
          let items = Array.isArray(session?.items) ? session.items : [];
          let index = items.findIndex(item => sameItem(item, current));
          if (index < 0) return current;
          if (index === items.length - 1 && session?.more === true && typeof loadMore === 'function') {
            await loadMore();
            session = getSession();
            items = Array.isArray(session?.items) ? session.items : [];
            index = items.findIndex(item => sameItem(item, current));
          }
          if (index >= 0 && index < items.length - 1) {
            const item = items[index + 1];
            if (typeof onNavigate === 'function') onNavigate(item);
            return api.open(item);
          }
          publish({ status:'ready', item:current, detail:current, complete:true });
          return current;
        })().finally(() => { moveRequest = null; });
        return moveRequest;
      },
      share(url) {
        if (shareRequest) return shareRequest;
        if (!current || typeof share !== 'function') return Promise.reject(new Error('Sharing is unavailable.'));
        const detail = current;
        publish({ status:'sharing', item:current, detail });
        shareRequest = share(url).then(result => {
          publish({ status:result, item:current, detail });
          return result;
        }).catch(error => {
          publish({ status:error?.name === 'AbortError' ? 'share-canceled' : 'share-error', item:current, detail, error });
          throw error;
        }).finally(() => { shareRequest = null; });
        return shareRequest;
      },
      claim(detail) {
        return run('claim', 'claiming', 'claimed', detail);
      },
      reopen(detail) {
        return run('reopen', 'reopening', 'reopened', detail);
      },
    };
    if (navigationRoot) {
      navigationRoot.querySelector('#previous-search-result').addEventListener('click', () => api.previous().catch(() => {}));
      navigationRoot.querySelector('#next-search-result').addEventListener('click', () => api.next().catch(() => {}));
    }
    return api;
  };
});