#!/usr/bin/env bun
/**
 * Publish one GitHub release per finished topic, versioned by timever
 * (`YYYYMMDD.HHMMSS.NNNNNNNNN`, UTC — https://gist.github.com/twolfson/de1b004dd22536b8e668).
 *
 * "Finished" is topics.ts's rule — every core sub-issue closed — the same one
 * close-topics.ts closes the topic issue on, and the version is the instant
 * the LAST core problem closed. Keying off the sub-issues rather than the
 * topic issue lets this run as the tail of Close Solved: the push that closes
 * a topic's final core problem releases it in the same run, without waiting
 * for close-topics to chain after it. The topic issue itself closes seconds
 * later, on the same day.
 *
 * Each release is a changelog snapshot at that instant: the topic's problem
 * sub-issues grouped as closed on the finish day (ET), closed earlier, and
 * open at release, each with its set, difficulty, and the solution files as
 * they stood in the tagged commit — the last main commit before the finish.
 *
 * The tag is annotated and backdated (tagger date = finish), so
 * `git tag --sort=taggerdate` reads as the campaign's history even for tags
 * minted by a backfill. The release's own published date cannot be backdated
 * (the API has no field for it), so the docs changelog dates each entry from
 * this timever tag instead (`releasesDatedByTag` in apps/docs/blume.config.ts)
 * — the tag format is that contract.
 *
 * Reconciles instead of reacting: every finished topic without a release gets
 * one, so a first run backfills the whole campaign; an existing release keeps
 * its tag and commit and only has its body rewritten when render() would say
 * something else. Re-runs with nothing new are no-ops.
 * A release is found by the marker comment in its body, never by tag name, so
 * reopening and re-closing a core problem can never mint a second release.
 * A tag that exists without its release (a run that died between the two) is
 * reused, not re-created.
 *
 *   bun apps/cli/release-topics.ts            # tag, push, release, fix bodies
 *   bun apps/cli/release-topics.ts --dry-run  # print the would-be releases
 *
 * Auth: GH_TOKEN / GITHUB_TOKEN, else `gh auth token` (needs contents: write).
 * Git:  a clone with full history, an `origin` it may push tags to, and a
 *       committer identity (the tagger).
 */
import { etDate } from "../api/src/srs.ts";
import { github } from "./github.ts";
import { markdownTable, printTable, writeStepSummary } from "./report.ts";
import { coreSet, labelValue, readProblems, type Problem } from "./topics.ts";
import { ROOT, parseWorkPath } from "./work.ts";

const DRY =
  process.argv.includes("--dry-run") ||
  process.env.DRY_RUN === "1" ||
  process.env.DRY_RUN === "true";

/** The docs site (apps/docs/blume.config.ts `deployment.site`); sync publishes `/<num>` short links. */
const DOCS_SITE = "https://lc.prd.lk";
const TIMEVER = "https://gist.github.com/twolfson/de1b004dd22536b8e668";

const gh = await github();

function git(...args: string[]): string {
  const run = Bun.spawnSync(["git", ...args], { cwd: ROOT });
  if (run.exitCode !== 0) throw new Error(`git ${args.join(" ")}: ${run.stderr.toString().trim()}`);
  return run.stdout.toString().trim();
}

// ── topics ───────────────────────────────────────────────────────

interface Topic {
  number: number;
  title: string;
  milestone: string | null;
  body: string;
}

/** Narrow one /issues element; the `topic` label filter cannot exclude PRs. */
function readTopic(value: unknown): Topic | undefined {
  if (!value || typeof value !== "object") return;
  if ("pull_request" in value) return;
  if (!("number" in value) || typeof value.number !== "number") return;
  if (!("title" in value) || typeof value.title !== "string") return;
  const milestone =
    "milestone" in value &&
    value.milestone &&
    typeof value.milestone === "object" &&
    "title" in value.milestone &&
    typeof value.milestone.title === "string"
      ? value.milestone.title
      : null;
  const body = "body" in value && typeof value.body === "string" ? value.body : "";
  return { number: value.number, title: value.title, milestone, body };
}

interface Finished {
  topic: Topic;
  problems: Problem[];
  core: number[];
  finishedAt: string;
}

// Closed and open topics alike: the rule reads the sub-issues, so a topic
// finished moments ago (close-topics not yet run) releases now.
const finished: Finished[] = [];
for await (const raw of gh.list(`/repos/${gh.repo}/issues?labels=topic&state=all`)) {
  const topic = readTopic(raw);
  if (!topic) continue;
  const problems = await readProblems(gh, topic.number);
  const core = coreSet(problems);
  if (core.finishedAt) finished.push({ topic, problems, core: core.all, finishedAt: core.finishedAt });
}
// Oldest first, so a backfill creates releases in campaign order.
finished.sort((a, b) => a.finishedAt.localeCompare(b.finishedAt) || a.topic.number - b.topic.number);

// ── existing releases ────────────────────────────────────────────

/** Topic -> its release. Name and body are kept in sync with the render on every run. */
const released = new Map<number, { id: number; tag: string; name: string; body: string }>();
for await (const raw of gh.list(`/repos/${gh.repo}/releases`)) {
  if (!raw || typeof raw !== "object") continue;
  if (!("id" in raw) || typeof raw.id !== "number") continue;
  if (!("tag_name" in raw) || typeof raw.tag_name !== "string") continue;
  if (!("body" in raw) || typeof raw.body !== "string") continue;
  const name = "name" in raw && typeof raw.name === "string" ? raw.name : "";
  const m = raw.body.match(/<!-- release-topics: #(\d+) -->/);
  if (m) released.set(Number(m[1]), { id: raw.id, tag: raw.tag_name, name, body: raw.body });
}

// ── timever ──────────────────────────────────────────────────────

/**
 * Timever of an instant. The API reports whole seconds, so SUBTIME is the
 * tiebreak: two topics finishing in the same second (one push closing both
 * last core problems) get consecutive nanoseconds, in (instant, topic) order.
 */
const tags = new Map<number, string>(); // topic -> tag
{
  let prev = "";
  let ns = 0;
  for (const f of finished) {
    const iso = new Date(f.finishedAt).toISOString(); // 2026-09-24T18:36:38.000Z
    const base = `${iso.slice(0, 10).replaceAll("-", "")}.${iso.slice(11, 19).replaceAll(":", "")}`;
    ns = base === prev ? ns + 1 : Number(iso.slice(20, 23)) * 1_000_000;
    prev = base;
    tags.set(f.topic.number, `${base}.${String(ns).padStart(9, "0")}`);
  }
}

// ── release body ─────────────────────────────────────────────────

const ET_WHEN = new Intl.DateTimeFormat("en-US", {
  timeZone: "America/New_York",
  weekday: "short",
  month: "short",
  day: "numeric",
  year: "numeric",
  hour: "numeric",
  minute: "2-digit",
});
const ET_DAY = new Intl.DateTimeFormat("en-US", {
  timeZone: "America/New_York",
  month: "short",
  day: "numeric",
});

/** Topic body sections worth carrying into the changelog (skipped while still `TODO`). */
const NOTES = ["Trigger", "Invariant", "Trap"] as const;

function bodyField(body: string, field: string): string | undefined {
  return body.match(new RegExp(`^\\*\\*${field}:\\*\\*\\s*(.+)$`, "m"))?.[1]?.trim();
}

function bodySection(body: string, heading: string): string | undefined {
  const m = body.match(new RegExp(`^### ${heading}\\n([\\s\\S]*?)(?=^### |(?![\\s\\S]))`, "m"));
  const text = m?.[1]?.trim();
  return text && text !== "TODO" ? text : undefined;
}

function render(f: Finished, tag: string, sha: string, files: Map<number, string[]>): string {
  const { topic, problems } = f;
  const finishDay = etDate(new Date(f.finishedAt));
  // Snapshot at the finish instant: a problem closed later was open then.
  const closedBy = (p: Problem) => p.closedAt !== null && p.closedAt <= f.finishedAt;
  const onDay = problems.filter((p) => closedBy(p) && etDate(new Date(p.closedAt!)) === finishDay);
  const earlier = problems.filter((p) => closedBy(p) && etDate(new Date(p.closedAt!)) !== finishDay);
  const open = problems.filter((p) => !closedBy(p));

  const row = (p: Problem): string[] => {
    const lc = Number(p.title.match(/^LC (\d+)/)?.[1]);
    const code = closedBy(p)
      ? (files.get(lc) ?? []).map(
          (path) => `[${path.slice(path.lastIndexOf(".") + 1)}](https://github.com/${gh.repo}/blob/${tag}/${encodeURI(path)})`,
        )
      : [];
    return [
      `#${p.number}`,
      p.title,
      labelValue(p, "set:") ?? "—",
      labelValue(p, "diff:") ?? "—",
      closedBy(p) ? ET_DAY.format(new Date(p.closedAt!)) : "—",
      code.length ? [...code, `[docs](${DOCS_SITE}/${lc})`].join(" · ") : "—",
    ];
  };
  const table = (list: Problem[]) =>
    markdownTable([["Issue", "Problem", "Set", "Difficulty", "Closed (ET)", "Solution"], ...list.map(row)]);

  // Blume's changelog derives each page's meta description from the opening
  // prose, stripping markdown and line breaks without adding a space — so lead
  // with one self-contained sentence and keep the fields on one `·` line.
  const when = ET_WHEN.format(new Date(f.finishedAt));
  const summary =
    `Finished ${when} ET: all ${f.core.length} core problems closed, ` +
    `${onDay.length} ${onDay.length === 1 ? "problem" : "problems"} closed that day.`;
  const fields: string[] = [];
  const scheduled = bodyField(topic.body, "Scheduled");
  if (scheduled) fields.push(`**Scheduled:** ${scheduled}`);
  if (topic.milestone) fields.push(`**Phase:** ${topic.milestone}`);
  fields.push(`**Topic:** #${topic.number}`);
  const buildsOn = bodyField(topic.body, "Builds on");
  if (buildsOn) fields.push(`**Builds on:** ${buildsOn}`);
  // The marker is how a later run finds this release; see the file header.
  const sections = [`<!-- release-topics: #${topic.number} -->\n${summary}`, fields.join(" · ")];
  sections.push(`### Closed ${ET_DAY.format(new Date(f.finishedAt))} — the day the topic finished\n\n${table(onDay)}`);
  if (earlier.length) sections.push(`### Closed earlier\n\n${table(earlier)}`);
  if (open.length) sections.push(`### Open at release\n\n${table(open)}`);
  const notes = NOTES.flatMap((h) => {
    const text = bodySection(topic.body, h);
    return text ? [`**${h}.** ${text}`] : [];
  });
  if (notes.length) sections.push(`### Notes\n\n${notes.join("\n\n")}`);
  sections.push(
    `---\n\n\`${tag}\` is [timever](${TIMEVER}) for the UTC instant the core set completed; ` +
      `it tags ${sha.slice(0, 7)}, the last main commit before it.`,
  );
  return `${sections.join("\n\n")}\n`;
}

// ── reconcile ────────────────────────────────────────────────────

const latest = finished.at(-1)?.topic.number;
const report: string[][] = [];
const previews: string[] = [];
let created = 0;
let updated = 0;

for (const f of finished) {
  const { topic } = f;
  const finishedEt = etDate(new Date(f.finishedAt));
  const existing = released.get(topic.number);
  // An existing release keeps its tag and commit; only its name and body are
  // reconciled. Its tag may postdate this clone (released by another run), so
  // fetch it when missing — read-only, so a dry run does it too.
  const tag = existing?.tag ?? tags.get(topic.number)!;
  if (existing && Bun.spawnSync(["git", "rev-parse", "-q", "--verify", `refs/tags/${tag}`], { cwd: ROOT }).exitCode !== 0) {
    git("fetch", "-q", "origin", `refs/tags/${tag}:refs/tags/${tag}`);
  }
  const sha = existing
    ? git("rev-parse", `${tag}^{commit}`)
    : git("rev-list", "-1", "--first-parent", `--before=${f.finishedAt}`, "HEAD");
  if (!sha) {
    report.push([`#${topic.number}`, topic.title, finishedEt, tag, "ERROR: no commit before finish"]);
    continue;
  }
  // LC number -> its first-solve files in the tagged tree. Keyed by file name,
  // like firstSolved(): tags before the bucket split see `work/<Difficulty>/…`,
  // and the work/3 + work/7 re-solves are not the solve that closed the issue.
  const files = new Map<number, string[]>();
  for (const path of git("ls-tree", "-r", "--name-only", sha, "--", "work").split("\n")) {
    const bucket = parseWorkPath(path.slice("work/".length))?.bucket;
    const lc = path.match(/\/(\d+)\.[^/]+\.(?:js|py)$/)?.[1];
    if (!lc || (bucket && bucket !== 1)) continue;
    files.set(Number(lc), [...(files.get(Number(lc)) ?? []), path]);
  }
  const body = render(f, tag, sha, files);
  const name = topic.title;

  if (existing) {
    if (existing.body === body && existing.name === name) {
      report.push([`#${topic.number}`, topic.title, finishedEt, tag, "released"]);
    } else if (DRY) {
      previews.push(`## ${name} (${tag})\n\n${body}`);
      report.push([`#${topic.number}`, topic.title, finishedEt, tag, "would update"]);
    } else {
      await gh.api(`/repos/${gh.repo}/releases/${existing.id}`, {
        method: "PATCH",
        body: JSON.stringify({ name, body }),
      });
      report.push([`#${topic.number}`, topic.title, finishedEt, tag, "updated"]);
      updated++;
    }
    continue;
  }

  if (DRY) {
    previews.push(`## ${name} (${tag})\n\n${body}`);
    report.push([`#${topic.number}`, topic.title, finishedEt, tag, "would release"]);
    continue;
  }

  const remote = git("ls-remote", "--tags", "origin", `refs/tags/${tag}`);
  if (!remote) {
    const local = Bun.spawnSync(["git", "rev-parse", "-q", "--verify", `refs/tags/${tag}`], { cwd: ROOT });
    if (local.exitCode !== 0) {
      const tagged = Bun.spawnSync(
        ["git", "tag", "-a", tag, sha, "-m", `${topic.title} (#${topic.number})\n\nCore set complete: ${f.core.map((n) => `#${n}`).join(", ")}`],
        { cwd: ROOT, env: { ...process.env, GIT_COMMITTER_DATE: f.finishedAt } },
      );
      if (tagged.exitCode !== 0) throw new Error(`git tag ${tag}: ${tagged.stderr.toString().trim()}`);
    }
    git("push", "origin", `refs/tags/${tag}`);
  }
  await gh.api(`/repos/${gh.repo}/releases`, {
    method: "POST",
    body: JSON.stringify({
      tag_name: tag,
      name,
      body,
      make_latest: topic.number === latest ? "true" : "false",
    }),
  });
  report.push([`#${topic.number}`, topic.title, finishedEt, tag, "released now"]);
  created++;
}

// ── report ───────────────────────────────────────────────────────

if (previews.length) console.log(`${previews.join("\n")}\n`);
const rows = [["topic", "title", "finished (ET)", "tag", "status"], ...report];
printTable(rows);
const would = (status: string) => report.filter((r) => r[4] === status).length;
console.log(
  `\n${finished.length} finished topics · ` +
    (DRY
      ? `would release ${would("would release")}, update ${would("would update")}`
      : `released ${created}, updated ${updated}`),
);

await writeStepSummary(
  `### release-topics${DRY ? " (dry run)" : ""}\n\n` +
    `${finished.length} finished topics, ${released.size} already released.\n\n` +
    (report.length ? `${markdownTable(rows)}\n` : "No finished topics.\n") +
    (previews.length ? `\n${previews.join("\n")}` : ""),
);