#!/usr/bin/env node
/**
 * Build-time generator: walks `content/docs/**` and produces
 * `lib/generated/contributors.json`, keyed by each file's repo-relative
 * path. Values are sorted by commit count desc.
 *
 *   {
 *     "content/docs/getting-started.mdx": [
 *       { "login": "penguine-ip", "name": "Jeffrey Ip",
 *         "avatarUrl": "…", "url": "…", "commits": 12 },
 *       …
 *     ]
 *   }
 *
 * How the GitHub linking works: `git log` gives us (email, name) but no
 * GitHub handle. We resolve email→login via `GET /repos/{owner}/{repo}/
 * commits/{sha}` — GitHub does the email-to-user lookup server-side and
 * returns `author.login` / `author.avatar_url` / `author.html_url`. One
 * API call per unique email (not per commit), cached in
 * `lib/generated/.contributors-cache.json` so subsequent runs are ~free.
 *
 * Bots (`…[bot]` login suffix) are excluded. Commits whose email doesn't
 * resolve to a GitHub user are dropped — no point showing a ghost.
 *
 * Failure modes handled gracefully (all exit 0 so builds don't break):
 *   - Not in a git repo, a shallow git checkout, or no commits touch
 *     content/docs: keeps the previous JSON file if one exists, otherwise
 *     writes `{}`. This matters for hosted builds that may not expose the
 *     full git history needed by `git log --follow`.
 *   - GitHub API 403 / rate-limited: keeps existing cache entries,
 *     skips the uncached emails, warns.
 *
 * Env:
 *   GITHUB_TOKEN  Optional; bumps GitHub API rate limit from 60/hr to
 *                 5000/hr. In CI, wire the built-in `GITHUB_TOKEN`.
 *
 * Run: `npm run contributors`  (also runs pre-build).
 */
import { execSync } from "node:child_process";
import {
  readdirSync,
  readFileSync,
  writeFileSync,
  mkdirSync,
  existsSync,
  statSync,
} from "node:fs";
import { join, relative } from "node:path";

// Sections that display a contributors list. Changelog and blog are
// intentionally omitted — blog posts have their own author byline, and
// changelog entries are attributed by release.
const CONTENT_DIRS = [
  "content/docs",
  "content/guides",
  "content/tutorials",
  "content/integrations",
];
const OUTPUT = "lib/generated/contributors.json";
const CACHE = "lib/generated/.contributors-cache.json";
const REPO_CONTRIBUTORS = "lib/generated/repo-contributors.json";

// Pages that replace older docs should keep the original page attribution.
const PAGE_CONTRIBUTOR_ALIASES = {
  "content/docs/introduction.mdx": "content/docs/getting-started.mdx",
};

// Some commit emails are not linked to a public GitHub identity, so the
// commit API returns `author: null`. For those cases we maintain a tiny
// email->login fallback and hydrate the avatar/profile URL from the
// repo-wide contributors manifest.
const AUTHOR_LOGIN_ALIASES = {
  "jeffreyip@confident-ai.com": "penguine-ip",
};

// Read repo coords from lib/shared.ts so there's one source of truth.
// Parsing literals avoids having to compile the TS file at script time.
function readGitConfig() {
  const src = readFileSync("lib/shared.ts", "utf8");
  const user = src.match(/user:\s*['"]([^'"]+)['"]/)?.[1];
  const repo = src.match(/repo:\s*['"]([^'"]+)['"]/)?.[1];
  if (!user || !repo)
    throw new Error("could not parse gitConfig from lib/shared.ts");
  return { user, repo };
}

function tryExec(cmd) {
  try {
    return execSync(cmd, {
      encoding: "utf8",
      stdio: ["ignore", "pipe", "ignore"],
    }).trim();
  } catch {
    return null;
  }
}

function inGitRepo() {
  return tryExec("git rev-parse --is-inside-work-tree") === "true";
}

function inShallowRepo() {
  return tryExec("git rev-parse --is-shallow-repository") === "true";
}

function walkMdx(dir, acc = []) {
  if (!existsSync(dir)) return acc;
  for (const entry of readdirSync(dir)) {
    const full = join(dir, entry);
    const s = statSync(full);
    if (s.isDirectory()) walkMdx(full, acc);
    else if (entry.endsWith(".mdx") || entry.endsWith(".md")) acc.push(full);
  }
  return acc;
}

// `git log --follow` so renames don't reset attribution. %x09 = tab, so
// we don't have to worry about author names containing our delimiter.
function gitCommitsForFile(file) {
  const out = tryExec(
    `git log --follow --format="%H%x09%ae%x09%an" -- "${file}"`
  );
  if (!out) return [];
  return out
    .split("\n")
    .filter(Boolean)
    .map((line) => {
      const [sha, email, name] = line.split("\t");
      return { sha, email: email.toLowerCase(), name };
    });
}

function loadCache() {
  if (!existsSync(CACHE)) return {};
  try {
    return JSON.parse(readFileSync(CACHE, "utf8"));
  } catch {
    return {};
  }
}

function loadRepoContributors() {
  if (!existsSync(REPO_CONTRIBUTORS)) return {};
  try {
    const list = JSON.parse(readFileSync(REPO_CONTRIBUTORS, "utf8"));
    return Object.fromEntries(
      Array.isArray(list)
        ? list
            .filter((entry) => entry?.login && entry?.avatarUrl && entry?.url)
            .map((entry) => [entry.login, entry])
        : []
    );
  } catch {
    return {};
  }
}

function loadExistingManifest() {
  if (!existsSync(OUTPUT)) return {};
  try {
    const manifest = JSON.parse(readFileSync(OUTPUT, "utf8"));
    return manifest && typeof manifest === "object" && !Array.isArray(manifest)
      ? manifest
      : {};
  } catch {
    return {};
  }
}

function saveJson(path, obj) {
  mkdirSync(join(path, ".."), { recursive: true });
  writeFileSync(path, JSON.stringify(obj, null, 2) + "\n");
}

function keepExistingOrWriteEmpty(path) {
  if (existsSync(path)) {
    console.warn(`[contributors] keeping existing ${path}.`);
    return;
  }
  saveJson(path, {});
}

function findCommitMetaForEmail(perFile, email) {
  for (const byEmail of perFile.values()) {
    const entry = byEmail.get(email);
    if (entry) return entry;
  }
  return null;
}

async function resolveAuthor(sha, { user, repo, token }) {
  const headers = {
    "User-Agent": "deepeval-docs-contributors",
    Accept: "application/vnd.github+json",
  };
  if (token) headers.Authorization = `Bearer ${token}`;
  const res = await fetch(
    `https://api.github.com/repos/${user}/${repo}/commits/${sha}`,
    { headers }
  );
  if (res.status === 403 || res.status === 429) throw new Error(`rate_limited`);
  if (!res.ok) return null; // 404 (commit not on this remote yet) → treat as unresolvable
  const body = await res.json();
  const a = body?.author;
  if (!a?.login) return null; // commit exists but email isn't linked to a GH user
  return {
    login: a.login,
    // Prefer the commit-author display name; fall back to the GH user's
    // `name` field. The API's `user.name` endpoint would give us the
    // canonical one but costs another request — not worth it.
    name: body?.commit?.author?.name || a.login,
    avatarUrl: a.avatar_url,
    url: a.html_url,
  };
}

function isBot(author) {
  return (
    author?.login?.endsWith("[bot]") || /\[bot\]$/.test(author?.name ?? "")
  );
}

async function main() {
  if (!inGitRepo()) {
    console.warn(
      "[contributors] not inside a git repo; cannot regenerate contributors manifest."
    );
    keepExistingOrWriteEmpty(OUTPUT);
    return;
  }

  if (inShallowRepo()) {
    console.warn(
      "[contributors] shallow git checkout; keeping existing contributors manifest."
    );
    keepExistingOrWriteEmpty(OUTPUT);
    return;
  }

  const { user, repo } = readGitConfig();
  const token = process.env.GITHUB_TOKEN || process.env.GH_TOKEN;
  const cache = loadCache();
  const repoContributors = loadRepoContributors();

  const files = CONTENT_DIRS.flatMap((d) => walkMdx(d));
  if (files.length === 0) {
    console.warn(
      `[contributors] no MDX files found under ${CONTENT_DIRS.join(", ")}.`
    );
    keepExistingOrWriteEmpty(OUTPUT);
    return;
  }
  const fileSet = new Set(files.map((file) => relative(".", file)));

  // First pass: gather per-file commit metadata (all local, no network).
  const perFile = new Map(); // relPath → Map<email, { name, commits, sha }>
  for (const file of files) {
    const rel = relative(".", file);
    const commits = gitCommitsForFile(file);
    if (commits.length === 0) continue;
    const byEmail = new Map();
    for (const c of commits) {
      const prev = byEmail.get(c.email) ?? {
        name: c.name,
        commits: 0,
        sha: c.sha,
      };
      prev.commits += 1;
      byEmail.set(c.email, prev);
    }
    perFile.set(rel, byEmail);
  }

  // Second pass: resolve every unseen email to a GitHub user.
  const uniqueEmails = new Set();
  for (const byEmail of perFile.values())
    for (const e of byEmail.keys()) uniqueEmails.add(e);

  let resolved = 0,
    aliased = 0,
    skipped = 0,
    bot = 0,
    rateLimited = false;
  for (const email of uniqueEmails) {
    if (
      cache[email]?.name &&
      cache[email]?.login &&
      cache[email]?.avatarUrl &&
      cache[email]?.url
    ) {
      continue;
    }

    const aliasLogin = AUTHOR_LOGIN_ALIASES[email];
    if (aliasLogin && repoContributors[aliasLogin]) {
      const meta = findCommitMetaForEmail(perFile, email);
      cache[email] = {
        login: aliasLogin,
        name: meta?.name || aliasLogin,
        avatarUrl: repoContributors[aliasLogin].avatarUrl,
        url: repoContributors[aliasLogin].url,
      };
      aliased += 1;
      continue;
    }
    if (email in cache) continue;

    // Use any commit SHA associated with this email (they all resolve
    // to the same GH user for a given email).
    let sha;
    for (const byEmail of perFile.values()) {
      const entry = byEmail.get(email);
      if (entry) {
        sha = entry.sha;
        break;
      }
    }
    if (!sha) continue;
    try {
      const author = await resolveAuthor(sha, { user, repo, token });
      if (author && isBot(author)) {
        cache[email] = null;
        bot += 1;
        continue;
      }
      cache[email] = author;
      if (author) resolved += 1;
      else skipped += 1;
    } catch (e) {
      if (e.message === "rate_limited") {
        rateLimited = true;
        console.warn(
          "[contributors] GitHub API rate-limited; stopping resolution. Set GITHUB_TOKEN to raise the ceiling."
        );
        break;
      }
      console.warn(`[contributors] failed resolving ${email}: ${e.message}`);
      skipped += 1;
    }
  }

  saveJson(CACHE, cache);

  // Third pass: materialize the manifest using the (now populated) cache.
  const manifest = {};
  for (const [rel, byEmail] of perFile) {
    const list = [];
    const seenLogins = new Set();
    for (const [email, meta] of byEmail) {
      const author = cache[email];
      if (!author) continue;
      // Same GH user may have pushed from multiple emails — collapse.
      if (seenLogins.has(author.login)) {
        const existing = list.find((x) => x.login === author.login);
        if (existing) existing.commits += meta.commits;
        continue;
      }
      seenLogins.add(author.login);
      list.push({
        ...author,
        name: author.name || meta.name || author.login,
        commits: meta.commits,
      });
    }

    // Sort real committers by commit count, then alphabetical.
    list.sort(
      (a, b) => b.commits - a.commits || a.login.localeCompare(b.login)
    );
    if (list.length > 0) manifest[rel] = list;
  }

  // Hosted builds can have incomplete git history without being marked as
  // shallow. Never let a partial regeneration replace a richer checked-in
  // manifest entry for a page that still exists.
  const existingManifest = loadExistingManifest();
  let preserved = 0;
  for (const [rel, existingList] of Object.entries(existingManifest)) {
    if (!fileSet.has(rel) || !Array.isArray(existingList)) continue;
    const generatedList = manifest[rel];
    if (
      !Array.isArray(generatedList) ||
      existingList.length > generatedList.length
    ) {
      manifest[rel] = existingList;
      preserved += 1;
    }
  }

  for (const [target, source] of Object.entries(PAGE_CONTRIBUTOR_ALIASES)) {
    if (!fileSet.has(target) || !Array.isArray(manifest[source])) continue;
    manifest[target] = manifest[source].map((entry) => ({ ...entry }));
  }

  saveJson(OUTPUT, manifest);
  console.log(
    `[contributors] ${Object.keys(manifest).length} pages, ` +
      `resolved ${resolved} new author(s), aliased ${aliased}, skipped ${skipped}, bots filtered ${bot}, ` +
      `preserved ${preserved} existing page(s)` +
      (rateLimited ? " (rate-limited; re-run with GITHUB_TOKEN)" : "") +
      "."
  );
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});