#!/usr/bin/env bun
/**
 * Close the GitHub issue for every LeetCode problem actually solved under work/.
 *
 * Reconciles state instead of reacting to a push diff: any `problem`-labelled
 * issue whose LC number has an *implemented* solution file in work/ gets
 * closed. Only open issues are touched, so re-runs are no-ops and backfilling
 * needs no special casing. Removing a solution never reopens an issue.
 *
 * `bun run pick` scaffolds a statement header plus an empty function body, so
 * file existence alone means nothing — a stub must not close its issue. See
 * isImplemented().
 *
 *   bun scripts/close-solved.ts            # close matches
 *   bun scripts/close-solved.ts --dry-run  # report only, touch nothing
 *
 * Auth: GH_TOKEN / GITHUB_TOKEN, else falls back to `gh auth token`.
 */
import { basename, join } from "node:path";

import { github } from "./github.ts";
import { markdownTable, printTable, writeStepSummary } from "./report.ts";

const ROOT = join(import.meta.dir, "..");
const WORK = join(ROOT, "work");

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

// ── is the file a real solution or just a scaffolded stub? ────────

/** Placeholder bodies that leetcode-cli / a human leaves behind. */
const PLACEHOLDERS: Record<string, true> = { pass: true, "...": true, TODO: true };

/**
 * Decide whether a work/ file contains an implementation.
 *
 * The header comment is dropped the same way sync.ts splitSource() does it
 * (duplicated rather than imported, because sync.ts runs its whole pipeline on
 * import). Comments must go before any brace analysis: the scaffold's JSDoc
 * carries `@param {number[]}`, whose braces would otherwise read as a body.
 *
 * A brace-language file counts as implemented when at least one *innermost*
 * brace pair holds real content. That distinguishes a bare stub
 * (`function(nums) {}`) and a class-shaped design stub (every method body
 * empty) from any genuine solution, whose innermost block always has code.
 */
function isImplemented(src: string, lang: "js" | "py"): boolean {
  if (lang === "py") {
    const open = src.indexOf('"""');
    const close = src.indexOf('"""', open + 3);
    const code = open === -1 || close === -1 ? src : src.slice(close + 3);
    for (const raw of code.split("\n")) {
      const line = raw.replace(/#.*$/, "").trim();
      if (!line || PLACEHOLDERS[line]) continue;
      if (/^(?:@|def\s|class\s)/.test(line)) continue;
      return true; // a statement inside some def body
    }
    return false;
  }

  const headerEnd = src.indexOf("*/");
  const body = headerEnd === -1 ? src : src.slice(headerEnd + 2);
  const code = body.replace(/\/\*[\s\S]*?\*\//g, " ").replace(/\/\/.*$/gm, " ");

  let innermost = -1;
  for (let i = 0; i < code.length; i++) {
    if (code[i] === "{") {
      innermost = i;
    } else if (code[i] === "}" && innermost !== -1) {
      const inner = code.slice(innermost + 1, i).replace(/[\s;]/g, "");
      if (inner && !PLACEHOLDERS[inner]) return true;
      innermost = -1; // measured; the enclosing pair is not innermost
    }
  }
  return false;
}

// ── repo + auth ──────────────────────────────────────────────────

const gh = await github();

// ── work/ inventory ──────────────────────────────────────────────

interface WorkEntry {
  files: string[];
  implemented: boolean;
}

/** LC number -> solution files (a problem may have both js and py). */
const work = new Map<number, WorkEntry>();
for await (const rel of new Bun.Glob("**/*.{js,py}").scan(WORK)) {
  const m = basename(rel).match(/^(\d+)\.(.+)\.(?:js|py)$/);
  if (!m) {
    console.warn(`skip (unrecognized name): work/${rel}`);
    continue;
  }
  const num = Number(m[1]);
  const src = await Bun.file(join(WORK, rel)).text();
  const implemented = isImplemented(src, rel.endsWith(".py") ? "py" : "js");
  const entry = work.get(num);
  if (entry) {
    entry.files.push(`work/${rel}`);
    entry.implemented ||= implemented;
  } else {
    work.set(num, { files: [`work/${rel}`], implemented });
  }
}

// ── open problem issues ──────────────────────────────────────────

interface ProblemIssue {
  number: number;
  set: string;
}

/**
 * Narrow one element of the /issues payload to the fields this script needs.
 * Returns undefined for pull requests and for anything whose title is not a
 * `LC <num> ...` problem, which is how non-curriculum rows get skipped.
 */
function readProblemIssue(
  value: unknown,
): { lc: number; issue: ProblemIssue } | undefined {
  if (!value || typeof value !== "object") return;
  if ("pull_request" in value) return; // the /issues route also lists PRs
  if (!("number" in value) || typeof value.number !== "number") return;
  if (!("title" in value) || typeof value.title !== "string") return;
  const lc = value.title.match(/^LC (\d+) /);
  if (!lc) return;

  let set = "—";
  if ("labels" in value && Array.isArray(value.labels)) {
    for (const label of value.labels) {
      if (
        label &&
        typeof label === "object" &&
        "name" in label &&
        typeof label.name === "string" &&
        label.name.startsWith("set:")
      ) {
        set = label.name;
      }
    }
  }
  return { lc: Number(lc[1]), issue: { number: value.number, set } };
}

/** LC number -> open issue carrying the `problem` label. */
const open = new Map<number, ProblemIssue>();
for await (const raw of gh.list(`/repos/${gh.repo}/issues?labels=problem&state=open`)) {
  const parsed = readProblemIssue(raw);
  if (parsed) open.set(parsed.lc, parsed.issue);
}

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

const sha = process.env.GITHUB_SHA;
const report: string[][] = [];
let closed = 0;

for (const num of [...work.keys()].sort((a, b) => a - b)) {
  const entry = work.get(num)!;
  const issue = open.get(num);

  // Warm-ups and out-of-curriculum practice have no issue. Not an error.
  if (!issue) {
    report.push([`${num}`, "—", "—", "no open issue"]);
    continue;
  }
  if (!entry.implemented) {
    report.push([`${num}`, `#${issue.number}`, issue.set, "stub — skipped"]);
    continue;
  }
  if (DRY) {
    report.push([`${num}`, `#${issue.number}`, issue.set, "would close"]);
    continue;
  }

  const links = entry.files
    .map((f) =>
      sha ? `[\`${f}\`](https://github.com/${gh.repo}/blob/${sha}/${encodeURI(f)})` : `\`${f}\``,
    )
    .join(", ");
  await gh.closeIssue(
    issue.number,
    `Solved — solution committed at ${links}.\n\n` +
      "Closed automatically by `close-solved`. Fill in the close-out block above if you have not already.",
  );
  report.push([`${num}`, `#${issue.number}`, issue.set, "closed"]);
  closed++;
}

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

const rows = [["lc", "issue", "set", "status"], ...report];
printTable(rows);

const implemented = [...work.values()].filter((e) => e.implemented).length;
const actionable = report.filter((r) => r[3] !== "no open issue");
console.log(
  `\n${work.size} in work/ · ${implemented} implemented · ` +
    `${actionable.length} matched an open issue · ` +
    `${DRY ? `would close ${actionable.filter((r) => r[3] === "would close").length}` : `closed ${closed}`}`,
);

await writeStepSummary(
  `### close-solved${DRY ? " (dry run)" : ""}\n\n` +
    `${work.size} files in \`work/\`, ${implemented} implemented, ` +
    `${actionable.length} matched an open issue.\n\n` +
    (actionable.length
      ? `${markdownTable([rows[0]!, ...actionable])}\n`
      : "Nothing to close.\n"),
);