Ranking System v2 (#1186)

* Revise rank calculation

* Replace contributions by commits

* Lower average stats and S+ threshold

* Fix calculateRank.test.js

Missing key in dictionary constructor

Co-authored-by: Rick Staa <rick.staa@outlook.com>

* refactor: run prettier

* feat: change star weight to 0.75

* Separate PRs and issues

* Tweak weights

* Add count_private back

* fix: enable 'count_private' again

* test: fix tests

* refactor: improve code formatting

* Higher targets

---------

Co-authored-by: Rick Staa <rick.staa@outlook.com>

src/calculateRank.js

@@ -1,105 +1,72 @@
-/**
- * Calculates the probability of x taking on x or a value less than x in a normal distribution
- * with mean and standard deviation.
- *
- * @see https://stackoverflow.com/a/5263759/10629172
- *
- * @param {string} mean The mean of the normal distribution.
- * @param {number} sigma The standard deviation of the normal distribution.
- * @param {number} to The value to calculate the probability for.
- * @returns {number} Probability.
- */
-const normalcdf = (mean, sigma, to) => {
-  var z = (to - mean) / Math.sqrt(2 * sigma * sigma);
-  var t = 1 / (1 + 0.3275911 * Math.abs(z));
-  var a1 = 0.254829592;
-  var a2 = -0.284496736;
-  var a3 = 1.421413741;
-  var a4 = -1.453152027;
-  var a5 = 1.061405429;
-  var erf =
-    1 - ((((a5 * t + a4) * t + a3) * t + a2) * t + a1) * t * Math.exp(-z * z);
-  var sign = 1;
-  if (z < 0) {
-    sign = -1;
-  }
-  return (1 / 2) * (1 + sign * erf);
-};
+function expsf(x, lambda = 1) {
+  return 2 ** (-lambda * x);
+}
 
 /**
  * Calculates the users rank.
  *
  * @param {object} params Parameters on which the user's rank depends.
- * @param {number} params.totalRepos Total number of repos.
- * @param {number} params.totalCommits Total number of commits.
- * @param {number} params.contributions The number of contributions.
- * @param {number} params.followers The number of followers.
+ * @param {boolean} params.all_commits Whether `include_all_commits` was used.
+ * @param {number} params.commits Number of commits.
  * @param {number} params.prs The number of pull requests.
  * @param {number} params.issues The number of issues.
- * @param {number} params.stargazers The number of stars.
+ * @param {number} params.repos Total number of repos.
+ * @param {number} params.stars The number of stars.
+ * @param {number} params.followers The number of followers.
  * @returns {{level: string, score: number}}} The users rank.
  */
-const calculateRank = ({
-  totalRepos,
-  totalCommits,
-  contributions,
-  followers,
+function calculateRank({
+  all_commits,
+  commits,
   prs,
   issues,
-  stargazers,
-}) => {
-  const COMMITS_OFFSET = 1.65;
-  const CONTRIBS_OFFSET = 1.65;
-  const ISSUES_OFFSET = 1;
-  const STARS_OFFSET = 0.75;
-  const PRS_OFFSET = 0.5;
-  const FOLLOWERS_OFFSET = 0.45;
-  const REPO_OFFSET = 1;
+  repos, // unused
+  stars,
+  followers,
+}) {
+  const COMMITS_MEAN = all_commits ? 1000 : 250,
+    COMMITS_WEIGHT = 2;
+  const PRS_MEAN = 50,
+    PRS_WEIGHT = 3;
+  const ISSUES_MEAN = 25,
+    ISSUES_WEIGHT = 1;
+  const STARS_MEAN = 250,
+    STARS_WEIGHT = 4;
+  const FOLLOWERS_MEAN = 25,
+    FOLLOWERS_WEIGHT = 1;
 
-  const ALL_OFFSETS =
-    CONTRIBS_OFFSET +
-    ISSUES_OFFSET +
-    STARS_OFFSET +
-    PRS_OFFSET +
-    FOLLOWERS_OFFSET +
-    REPO_OFFSET;
+  const TOTAL_WEIGHT =
+    COMMITS_WEIGHT +
+    PRS_WEIGHT +
+    ISSUES_WEIGHT +
+    STARS_WEIGHT +
+    FOLLOWERS_WEIGHT;
 
-  const RANK_S_VALUE = 1;
-  const RANK_DOUBLE_A_VALUE = 25;
-  const RANK_A2_VALUE = 45;
-  const RANK_A3_VALUE = 60;
-  const RANK_B_VALUE = 100;
+  const rank =
+    (COMMITS_WEIGHT * expsf(commits, 1 / COMMITS_MEAN) +
+      PRS_WEIGHT * expsf(prs, 1 / PRS_MEAN) +
+      ISSUES_WEIGHT * expsf(issues, 1 / ISSUES_MEAN) +
+      STARS_WEIGHT * expsf(stars, 1 / STARS_MEAN) +
+      FOLLOWERS_WEIGHT * expsf(followers, 1 / FOLLOWERS_MEAN)) /
+    TOTAL_WEIGHT;
 
-  const TOTAL_VALUES =
-    RANK_S_VALUE +
-    RANK_DOUBLE_A_VALUE +
-    RANK_A2_VALUE +
-    RANK_A3_VALUE +
-    RANK_B_VALUE;
-
-  // prettier-ignore
-  const score = (
-    totalCommits * COMMITS_OFFSET +
-    contributions * CONTRIBS_OFFSET +
-    issues * ISSUES_OFFSET +
-    stargazers * STARS_OFFSET +
-    prs * PRS_OFFSET +
-    followers * FOLLOWERS_OFFSET +
-    totalRepos * REPO_OFFSET
-  ) / 100;
-
-  const normalizedScore = normalcdf(score, TOTAL_VALUES, ALL_OFFSETS) * 100;
+  const RANK_S_PLUS = 0.025;
+  const RANK_S = 0.1;
+  const RANK_A_PLUS = 0.25;
+  const RANK_A = 0.5;
+  const RANK_B_PLUS = 0.75;
 
   const level = (() => {
-    if (normalizedScore < RANK_S_VALUE) return "S+";
-    if (normalizedScore < RANK_DOUBLE_A_VALUE) return "S";
-    if (normalizedScore < RANK_A2_VALUE) return "A++";
-    if (normalizedScore < RANK_A3_VALUE) return "A+";
-    return "B+";
+    if (rank <= RANK_S_PLUS) return "S+";
+    if (rank <= RANK_S) return "S";
+    if (rank <= RANK_A_PLUS) return "A+";
+    if (rank <= RANK_A) return "A";
+    if (rank <= RANK_B_PLUS) return "B+";
+    return "B";
   })();
 
-  return { level, score: normalizedScore };
-};
+  return { level, score: rank * 100 };
+}
 
 export { calculateRank };
 export default calculateRank;

src/fetchers/stats-fetcher.js

@@ -192,7 +192,7 @@ const fetchStats = async (
     totalIssues: 0,
     totalStars: 0,
     contributedTo: 0,
-    rank: { level: "C", score: 0 },
+    rank: { level: "B", score: 0 },
   };
 
   let res = await statsFetcher(username);
@@ -220,53 +220,44 @@ const fetchStats = async (
 
   const user = res.data.data.user;
 
-  // populate repoToHide map for quick lookup
-  // while filtering out
-  let repoToHide = {};
-  if (exclude_repo) {
-    exclude_repo.forEach((repoName) => {
-      repoToHide[repoName] = true;
-    });
-  }
-
   stats.name = user.name || user.login;
-  stats.totalIssues = user.openIssues.totalCount + user.closedIssues.totalCount;
 
-  // normal commits
-  stats.totalCommits = user.contributionsCollection.totalCommitContributions;
-
-  // if include_all_commits then just get that,
-  // since totalCommitsFetcher already sends totalCommits no need to +=
+  // if include_all_commits, fetch all commits using the REST API.
   if (include_all_commits) {
     stats.totalCommits = await totalCommitsFetcher(username);
+  } else {
+    stats.totalCommits = user.contributionsCollection.totalCommitContributions;
   }
 
-  // if count_private then add private commits to totalCommits so far.
+  // if count_private, add private contributions to totalCommits.
   if (count_private) {
     stats.totalCommits +=
       user.contributionsCollection.restrictedContributionsCount;
   }
 
   stats.totalPRs = user.pullRequests.totalCount;
+  stats.totalIssues = user.openIssues.totalCount + user.closedIssues.totalCount;
   stats.contributedTo = user.repositoriesContributedTo.totalCount;
 
-  // Retrieve stars while filtering out repositories to be hidden
+  // Retrieve stars while filtering out repositories to be hidden.
+  let repoToHide = new Set(exclude_repo);
+
   stats.totalStars = user.repositories.nodes
     .filter((data) => {
-      return !repoToHide[data.name];
+      return !repoToHide.has(data.name);
     })
     .reduce((prev, curr) => {
       return prev + curr.stargazers.totalCount;
     }, 0);
 
   stats.rank = calculateRank({
-    totalCommits: stats.totalCommits,
-    totalRepos: user.repositories.totalCount,
-    followers: user.followers.totalCount,
-    contributions: stats.contributedTo,
-    stargazers: stats.totalStars,
+    all_commits: include_all_commits,
+    commits: stats.totalCommits,
     prs: stats.totalPRs,
     issues: stats.totalIssues,
+    repos: user.repositories.totalCount,
+    stars: stats.totalStars,
+    followers: user.followers.totalCount,
   });
 
   return stats;