import axios from './githubAxios.js';
import util from 'util';
import cp from 'child_process';
import Handlebars from 'handlebars';
import fs from 'fs/promises';
import { colorize } from './helpers/colorize.js';

const exec = util.promisify(cp.exec);

const ONE_MB = 1024 * 1024;

const removeExtraLineBreaks = (str) => str.replace(/(?:\r\n|\r|\n){3,}/gm, '\r\n\r\n');

const cleanTemplate = (template) =>
  template
    .replace(/\n +/g, '\n')
    .replace(/^ +/, '')
    .replace(/\n\n\n+/g, '\n\n')
    .replace(/\n\n$/, '\n');

const getUserFromCommit = ((commitCache) => async (sha) => {
  try {
    if (commitCache[sha] !== undefined) {
      return commitCache[sha];
    }

    console.log(colorize()`fetch github commit info (${sha})`);

    const { data } = await axios.get(`https://api.github.com/repos/axios/axios/commits/${sha}`);

    return (commitCache[sha] = {
      ...data.commit.author,
      ...data.author,
      avatar_url_sm: data.author.avatar_url ? data.author.avatar_url + '&s=18' : '',
    });
  } catch (err) {
    return (commitCache[sha] = null);
  }
})({});

const getIssueById = ((cache) => async (id) => {
  if (cache[id] !== undefined) {
    return cache[id];
  }

  try {
    const { data } = await axios.get(`https://api.github.com/repos/axios/axios/issues/${id}`);

    return (cache[id] = data);
  } catch (err) {
    return null;
  }
})({});

const getUserInfo = ((userCache) => async (userEntry) => {
  const { email, commits } = userEntry;

  if (userCache[email] !== undefined) {
    return userCache[email];
  }

  console.log(colorize()`fetch github user info [${userEntry.name}]`);

  return (userCache[email] = {
    ...userEntry,
    ...(await getUserFromCommit(commits[0].hash)),
  });
})({});

const deduplicate = (authors) => {
  const loginsMap = {};
  const combined = {};

  const assign = (a, b) => {
    const { insertions, _deletions, _points, ...rest } = b;

    Object.assign(a, rest);

    a.insertions += insertions;
    a.deletions += insertions;
    a.insertions += insertions;
  };

  for (const [email, user] of Object.entries(authors)) {
    const { login } = user;
    let entry;

    if (login && (entry = loginsMap[login])) {
      assign(entry, user);
    } else {
      login && (loginsMap[login] = user);
      combined[email] = user;
    }
  }

  return combined;
};

const getReleaseInfo = ((releaseCache) => async (tag) => {
  if (releaseCache[tag] !== undefined) {
    return releaseCache[tag];
  }

  const isUnreleasedTag = !tag;

  const version = 'v' + tag.replace(/^v/, '');

  const command = isUnreleasedTag
    ? `npx auto-changelog --unreleased-only --stdout --commit-limit false --template json`
    : `npx auto-changelog ${
        version ? '--starting-version ' + version + ' --ending-version ' + version : ''
      } --stdout --commit-limit false --template json`;

  console.log(command);

  const { stdout } = await exec(command, { maxBuffer: 10 * ONE_MB });

  const release = JSON.parse(stdout)[0];

  if (release) {
    const authors = {};

    const commits = [
      ...release.commits,
      ...release.fixes.map((fix) => fix.commit),
      ...release.merges.map((fix) => fix.commit),
    ].filter(Boolean);

    const commitMergeMap = {};

    for (const merge of release.merges) {
      commitMergeMap[merge.commit.hash] = merge.id;
    }

    for (const { hash, author, email, insertions, deletions } of commits) {
      const entry = (authors[email] = authors[email] || {
        name: author,
        prs: [],
        email,
        commits: [],
        insertions: 0,
        deletions: 0,
      });

      entry.commits.push({ hash });

      let pr;

      if ((pr = commitMergeMap[hash])) {
        entry.prs.push(pr);
      }

      console.log(colorize()`Found commit [${hash}]`);

      entry.displayName = entry.name || author || entry.login;

      entry.github = entry.login ? `https://github.com/${encodeURIComponent(entry.login)}` : '';

      entry.insertions += insertions;
      entry.deletions += deletions;
      entry.points = entry.insertions + entry.deletions;
    }

    for (const [email, author] of Object.entries(authors)) {
      const entry = (authors[email] = await getUserInfo(author));

      entry.isBot = entry.type === 'Bot';
    }

    release.authors = Object.values(deduplicate(authors)).sort((a, b) => b.points - a.points);

    release.allCommits = commits;
  }

  releaseCache[tag] = release;

  return release;
})({});

const renderContributorsList = async (tag, template) => {
  const release = await getReleaseInfo(tag);

  const compile = Handlebars.compile(String(await fs.readFile(template)));

  const content = compile(release);

  return removeExtraLineBreaks(cleanTemplate(content));
};

const renderPRsList = async (
  tag,
  template,
  { comments_threshold = 5, awesome_threshold = 5, label = 'add_to_changelog' } = {}
) => {
  const release = await getReleaseInfo(tag);

  const prs = {};

  for (const merge of release.merges) {
    const pr = await getIssueById(merge.id);

    if (pr && pr.labels.find(({ name }) => name === label)) {
      const { reactions, body } = pr;
      prs[pr.number] = pr;
      pr.isHot = pr.comments > comments_threshold;
      const points =
        reactions['+1'] +
        reactions['hooray'] +
        reactions['rocket'] +
        reactions['heart'] +
        reactions['laugh'] -
        reactions['-1'];

      pr.isAwesome = points > awesome_threshold;

      let match;

      pr.messages = [];

      if (body) {
        const reg = /```+changelog\n*(.+?)?\n*```/gms;

        while ((match = reg.exec(body))) {
          match[1] && pr.messages.push(match[1]);
        }
      }
    }
  }

  release.prs = Object.values(prs);

  const compile = Handlebars.compile(String(await fs.readFile(template)));

  const content = compile(release);

  return removeExtraLineBreaks(cleanTemplate(content));
};

const getTagRef = async (tag) => {
  try {
    return (await exec(`git show-ref --tags "refs/tags/${tag}"`)).stdout.split(' ')[0];
  } catch (e) {
    // Do nothing
  }
};

export { renderContributorsList, getReleaseInfo, renderPRsList, getTagRef };