feat(api): migrate SRS ladder to +3/+7 and adjust rest‑day logic

apps/cli/work.ts

@@ -0,0 +1,180 @@
+/**
+ * The work/ layout: one directory per spaced-repetition window.
+ *
+ *   work/1/<Difficulty>/<Category>/<num>.<slug>.<ext>   first solve
+ *   work/3/<Difficulty>/<Category>/<num>.<slug>.<ext>   3-day blind re-solve
+ *   work/7/<Difficulty>/<Category>/<num>.<slug>.<ext>   7-day blind re-solve
+ *
+ * The bucket name is the review window in days — the same +3/+7 windows the
+ * campaign's `Spaced Repetition — <date>` issues use (WINDOWS in
+ * spaced-repetition.ts). Below the bucket the layout is leetcode-cli's own
+ * `workDir/Difficulty/Category/` shape, so a re-solve lands beside its first
+ * solve under a different bucket.
+ *
+ * A window is *owed* when the first solve is at least that many days old and
+ * the bucket has no file for that problem yet. Reconciled from the filesystem
+ * on every run the way close-solved.ts reconciles issues: no state file, no
+ * bookkeeping, and a re-solve closes its window just by existing — presence,
+ * not content, so a stub in work/3 counts as done the same way `bun run pick`
+ * treats a scaffold under work/1 as picked. The first solve is the one place
+ * content is read: an empty scaffold in work/1 owes nothing, it is simply
+ * unsolved (isImplemented() in source.ts, the same gate close-solved.ts uses
+ * before it closes an issue).
+ *
+ * "First solve" is the ET date of the commit that first added the problem's
+ * work/ file — the same push that closes its problem issue and therefore
+ * starts the campaign's +3/+7 windows. An uncommitted solution has no date and
+ * is never owed a review yet: you just solved it. ET dates and the date
+ * arithmetic come from apps/api/src/srs.ts so the local picker and D1 cannot
+ * disagree about what day it is.
+ *
+ * Library: side-effect-free on import — nothing scans or shells out until a
+ * function is called.
+ */
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { WINDOWS, type Window, daysBetween } from "../api/src/srs.ts";
+import { isImplemented } from "./source.ts";
+
+export const ROOT = join(import.meta.dir, "..", "..");
+export const WORK = join(ROOT, "work");
+
+// The windows are the SRS ladder's rungs: srs.ts defines them once and the
+// bucket directories are named after them. Re-exported so the picker needs
+// only this module to know the work/ layout.
+export { WINDOWS, type Window };
+
+/** work/1 is the first solve, the rest are the review windows. */
+export const BUCKETS = [1, ...WINDOWS] as const;
+export type Bucket = (typeof BUCKETS)[number];
+const BUCKET_BY_DIR: Record<string, Bucket> = { "1": 1, "3": 3, "7": 7 };
+
+export function bucketDir(bucket: Bucket): string {
+  return join(WORK, String(bucket));
+}
+
+export interface WorkFile {
+  lc: number;
+  slug: string;
+  bucket: Bucket;
+  /** Path relative to work/, bucket included. */
+  rel: string;
+  difficulty: string;
+  category: string;
+}
+
+/** `<num>.<slug>.<ext>` — the only file name the campaign scripts parse. */
+function parseName(name: string): { lc: number; slug: string } | null {
+  const m = name.match(/^(\d+)\.(.+)\.[A-Za-z0-9]+$/);
+  return m ? { lc: Number(m[1]), slug: m[2]! } : null;
+}
+
+/** Parse `1/Medium/Array/15.3sum.py` — null for anything off-layout. */
+export function parseWorkPath(rel: string): WorkFile | null {
+  const parts = rel.split("/");
+  const name = parts.pop();
+  const bucket = BUCKET_BY_DIR[parts[0] ?? ""];
+  if (name === undefined || bucket === undefined) return null;
+  const parsed = parseName(name);
+  if (!parsed) return null;
+  return { ...parsed, bucket, rel, difficulty: parts[1] ?? "", category: parts[2] ?? "" };
+}
+
+/** LC number -> its files in that bucket (a problem may have both js and py). */
+export function scanBucket(bucket: Bucket): Map<number, WorkFile[]> {
+  const files = new Map<number, WorkFile[]>();
+  for (const name of new Bun.Glob("**/*.*").scanSync({ cwd: bucketDir(bucket) })) {
+    const file = parseWorkPath(`${bucket}/${name}`);
+    if (!file) continue;
+    const found = files.get(file.lc);
+    if (found) found.push(file);
+    else files.set(file.lc, [file]);
+  }
+  return files;
+}
+
+/**
+ * LC number -> ET date of the commit that first added a work/ file for it.
+ *
+ * One `git log` over the whole of work/, oldest commit first, so the first
+ * date seen for a problem wins. Keyed by LC number rather than by path, which
+ * makes every past reshuffle of the directory layout — including the move into
+ * work/1 — irrelevant: the original add still counts. TZ + `format-local`
+ * put the dates on the ET calendar srs.ts speaks.
+ */
+export function firstSolved(): Map<number, string> {
+  const git = Bun.spawnSync(
+    [
+      "git",
+      "log",
+      "--reverse",
+      "--no-merges",
+      "--diff-filter=A",
+      "--date=format-local:%Y-%m-%d",
+      "--format=%ad",
+      "--name-only",
+      "--",
+      "work",
+    ],
+    { cwd: ROOT, env: { ...process.env, TZ: "America/New_York" } },
+  );
+  if (git.exitCode !== 0) {
+    throw new Error(`git log failed: ${git.stderr.toString().trim()}`);
+  }
+
+  const dates = new Map<number, string>();
+  let date = "";
+  for (const line of git.stdout.toString().split("\n")) {
+    if (/^\d{4}-\d{2}-\d{2}$/.test(line)) {
+      date = line;
+      continue;
+    }
+    const parsed = line === "" ? null : parseName(line.slice(line.lastIndexOf("/") + 1));
+    if (parsed && !dates.has(parsed.lc)) dates.set(parsed.lc, date);
+  }
+  return dates;
+}
+
+export interface Owed extends WorkFile {
+  /** ET date of the first solve. */
+  solved: string;
+  /** Days since the first solve — at least the window. */
+  days: number;
+}
+
+/**
+ * Both review windows for `today`, oldest solve first.
+ *
+ * Uncapped, unlike the review issue's WINDOW_CAP: the issue is one day's
+ * assignment, this is everything still owed. A window skipped for a day stays
+ * on the list until its file exists.
+ */
+export function reviewQueues(today: string): Map<Window, Owed[]> {
+  const dates = firstSolved();
+
+  // An empty scaffold under work/1 is a problem still unsolved, not one owing
+  // a review — the same call close-solved.ts makes before it closes an issue.
+  const solved: { file: WorkFile; date: string }[] = [];
+  for (const files of scanBucket(1).values()) {
+    const date = dates.get(files[0]!.lc);
+    if (date === undefined) continue; // uncommitted: you only just solved it
+    const file = files.find((f) =>
+      isImplemented(readFileSync(join(WORK, f.rel), "utf8"), f.rel.endsWith(".py") ? "py" : "js"),
+    );
+    if (file) solved.push({ file, date });
+  }
+
+  const queues = new Map<Window, Owed[]>();
+  for (const window of WINDOWS) {
+    const done = scanBucket(window);
+    const owed: Owed[] = [];
+    for (const { file, date } of solved) {
+      if (done.has(file.lc)) continue;
+      const days = daysBetween(date, today);
+      if (days >= window) owed.push({ ...file, solved: date, days });
+    }
+    owed.sort((a, b) => b.days - a.days || a.lc - b.lc);
+    queues.set(window, owed);
+  }
+  return queues;
+}