import logger from './logger.mjs';

function truncate(str, len = 26) {
  if (str.length <= len) return str;
  return `${str.slice(0, len)}...`;
}

const getCommentEvents = async (repo, lastEvents) => {
  // just fetch and return the results
  if (lastEvents == null) return repo.events.fetch();

  // if there is no next page, just return the passed in object
  if (!lastEvents.nextPage) return lastEvents;

  // fetch next items and append previous ones
  const newEvents = await lastEvents.nextPage.fetch();
  newEvents.items = [...lastEvents.items, ...newEvents.items];
  return newEvents;
};

export default async function getEvents(repo, { body, actor, pages = 4 } = {}) {
  // create a task array that we can reduce into a promise chain
  const chain = [];
  while (chain.length < pages) chain.push('page');

  const events = await chain.reduce(
    acc => acc.then(res => getCommentEvents(repo, res)),
    Promise.resolve()
  );

  return events.items
    .map(comment => {
      let skip = false;
      const isComment = comment.type === 'IssueCommentEvent';
      const bodyMatch = isComment && (!body || body.test(comment.payload.comment.body));
      const isActor = comment.actor.login === actor;

      // skip events that don't match the criteria
      if (!isComment) skip = true;
      if (comment.payload.action !== 'created') skip = true;
      if (!isActor) skip = true;
      if (isComment && !bodyMatch) skip = true;

      if (skip) {
        if (isActor) {
          logger.debug(
            `SKIP EVENT ${isComment ? `#${comment.payload.issue.number}` : comment.id}: ${
              comment.type
            } ${comment.payload.action} by ${comment.actor.login}`,
            isComment && !bodyMatch && `(${truncate(comment.payload.comment.body)})`
          );
        }
        return false;
      }

      return {
        id: comment.id,
        number: comment.payload.issue.number,
        owner: comment.payload.issue.user.login,
        labels: comment.payload.issue.labels.map(label => label.name),
        comment_id: comment.payload.comment.id,
        comment_author: comment.payload.comment.user.login,
        comment_body: comment.payload.comment.body,
      };
    })
    .filter(Boolean);
}