#!/usr/bin/env bun
// gstack-version-bump — deterministic version-state classifier + writer for /ship.
//
// Extracted from ship Step 12 prose (v2 plan T9, hybrid CLI extraction). The
// idempotency classification and the dual-write to VERSION + package.json are
// pure deterministic logic; running them as tested code removes the single
// worst /ship footgun — re-bumping an already-shipped branch — from prose the
// agent could skip or misread when the step lives in a lazy-loaded section.
//
// What STAYS agent judgment (NOT here): the bump-LEVEL decision (micro/patch vs
// minor/major, which may AskUserQuestion on feature signals) and the queue
// collision prompt. The slot pick itself is bin/gstack-next-version. This CLI
// only answers "what state am I in?" and "write this exact version".
//
// Subcommands:
//   classify --base <branch> [--version-path <p>]
//       Compares VERSION vs origin/<base>:VERSION vs package.json.version.
//       Emits JSON: { state, baseVersion, currentVersion, pkgVersion, pkgExists }
//       state ∈ FRESH | ALREADY_BUMPED | DRIFT_STALE_PKG | DRIFT_UNEXPECTED
//       Exit 0 on a decidable state (incl. DRIFT_UNEXPECTED — it's a real state
//       the caller must handle), exit 2 on bad args / unresolvable base.
//
//   write --version <X.Y.Z.W> [--version-path <p>]
//       Validates the 4-digit pattern, writes VERSION + package.json.version.
//       Use for the FRESH bump (or an approved queue rebump). Exit 3 on a
//       half-write (VERSION written, package.json failed) so the caller knows
//       drift exists; the next classify() will report DRIFT_STALE_PKG.
//
//   repair [--version-path <p>]
//       DRIFT_STALE_PKG path: sync package.json.version to the current VERSION
//       file. No bump. Validates the VERSION pattern first.
//
// Contract: classify NEVER writes. write/repair mutate VERSION + the manifest
// + npm lockfiles (package-lock.json / npm-shrinkwrap.json, when present)
// only. No git mutation, no network. Mirrors gstack-next-version's
// reader/writer split so /ship composes them.
//
// Manifest resolution (all three subcommands accept --package-json-path):
//   --package-json-path <p>  →  .gstack/package-json-path  →  ./package.json
// A repo whose only Node package lives in a subdirectory (web/, app/,
// frontend/) has no ROOT package.json. The tool used to report
// pkgExists:false there and write VERSION alone, leaving the manifest to be
// bumped by hand — the drift this tool exists to prevent, in the one layout
// where it silently did nothing (#2531).
//
// npm semver (decision 11, v1.67 fix-wave plan): VERSION is the 4-digit
// MAJOR.MINOR.PATCH.MICRO source of truth; npm rejects a fourth component,
// so the manifest and its lockfiles carry the npm-valid 3-digit translation
// (1.67.0.0 → 1.67.0). classify judges drift against the translated form
// (accepting the pre-v1.67 1:1 mirror as in-sync until the next write).

import { existsSync, readFileSync, realpathSync, writeFileSync } from "node:fs";
import { execFileSync } from "node:child_process";
import { dirname, isAbsolute, join, relative, resolve, sep } from "node:path";
import { extractVersion, isJsonVersionPath, npmVersion, setVersionInJson } from "../lib/version-source";

// 3- or 4-digit (#2501). gstack's own VERSION stays 4-digit MAJOR.MINOR.PATCH.
// MICRO and stays the source of truth, but a repo whose pinned version source
// is a package.json holds plain 3-digit semver, and rejecting it here meant
// /ship could not write a version at all in such a repo. See lib/version-source.ts.
const VERSION_RE = /^[0-9]+\.[0-9]+\.[0-9]+(\.[0-9]+)?$/;
const DEFAULT = "0.0.0.0";

type State = "FRESH" | "ALREADY_BUMPED" | "DRIFT_STALE_PKG" | "DRIFT_UNEXPECTED";

function fail(msg: string, code = 2): never {
  process.stderr.write(`gstack-version-bump: ${msg}\n`);
  process.exit(code);
}

function argVal(args: string[], flag: string): string | undefined {
  const i = args.indexOf(flag);
  return i >= 0 && i + 1 < args.length ? args[i + 1] : undefined;
}

/**
 * Containment guard: `.gstack/version-path` and `.gstack/package-json-path`
 * are repo-controlled content. Without this, a cloned repo pinning
 * `../../victim.json` — or an in-repo symlink pointing outside — turns a
 * routine bump into an arbitrary file overwrite outside the repository.
 * Rejects absolute paths, lexical `..` escapes, and symlink escapes (the
 * deepest EXISTING ancestor is realpath'd, so a not-yet-created VERSION
 * file is still checked through its parent directory).
 */
function assertRepoContained(cwd: string, rel: string, source: string): void {
  const root = realpathSync(cwd);
  const abs = resolve(root, rel);
  const lex = relative(root, abs);
  if (isAbsolute(rel) || lex === "" || lex.startsWith("..") || isAbsolute(lex)) {
    fail(`${source} ('${rel}') resolves outside the repository. Refusing to read or write it.`, 2);
  }
  let probe = abs;
  while (!existsSync(probe)) {
    const parent = dirname(probe);
    if (parent === probe) break;
    probe = parent;
  }
  let real: string;
  try {
    real = realpathSync(probe);
  } catch {
    return; // vanished between existsSync and realpath — the read/write will fail honestly on its own
  }
  if (real !== root && !real.startsWith(root + sep)) {
    fail(`${source} ('${rel}') resolves through a symlink to outside the repository. Refusing to read or write it.`, 2);
  }
}

/**
 * Resolve the version file's path RELATIVE to the repo root: --version-path,
 * else .gstack/version-path, else "VERSION".
 *
 * The relative form is what matters — `git show origin/<base>:<rel>` needs it
 * (an absolute path is unusable there). Callers used to
 * derive versionRel from the CLI flag alone (#2462), so a repo using the
 * .gstack/version-path pin had its local (pinned) version compared against
 * the BASE's root VERSION file: two different files. On a repo with no root
 * VERSION the base then always read 0.0.0.0, making every branch look FRESH —
 * and the pinned-JSON handling never engaged without the explicit flag.
 * Resolving once, here, keeps base and current reads in step.
 */
function resolveVersionRel(cwd: string, explicit?: string): string {
  if (explicit) {
    const rel = explicit.trim();
    assertRepoContained(cwd, rel, "--version-path");
    return rel;
  }
  const pin = join(cwd, ".gstack", "version-path");
  if (existsSync(pin)) {
    const p = readFileSync(pin, "utf-8").split("\n")[0]?.trim() ?? "";
    if (p) {
      assertRepoContained(cwd, p, ".gstack/version-path");
      return p;
    }
  }
  return "VERSION";
}


function readVersionFile(p: string, versionRel = "VERSION"): string {
  try {
    // extractVersion (#2501): a .json version-path is read as JSON (.version),
    // not whitespace-stripped raw text that turns a package.json into garbage.
    const v = extractVersion(readFileSync(p, "utf-8"), versionRel);
    return v || DEFAULT;
  } catch {
    return DEFAULT;
  }
}

/**
 * Resolve the manifest path: --package-json-path, else
 * .gstack/package-json-path, else "package.json" (#2531, mirrors
 * resolveVersionRel). A repo whose only Node package lives in a
 * subdirectory (web/, app/, frontend/) has no ROOT package.json, so the
 * old join(cwd, "package.json") reported pkgExists:false and every bump
 * silently wrote VERSION alone — leaving the manifest to be edited by
 * hand, which is exactly the drift this tool exists to prevent.
 */
function resolvePkgPath(cwd: string, explicit?: string): string {
  if (explicit) {
    const rel = explicit.trim();
    assertRepoContained(cwd, rel, "--package-json-path");
    return join(cwd, rel);
  }
  const pin = join(cwd, ".gstack", "package-json-path");
  if (existsSync(pin)) {
    const p = readFileSync(pin, "utf-8").split("\n")[0]?.trim() ?? "";
    if (p) {
      assertRepoContained(cwd, p, ".gstack/package-json-path");
      return join(cwd, p);
    }
  }
  return join(cwd, "package.json");
}

/** package.json version + existence, parsed without spawning node. */
function readPkgVersion(pkgPath: string): { exists: boolean; version: string } {
  if (!existsSync(pkgPath)) return { exists: false, version: "" };
  let raw: string;
  try {
    raw = readFileSync(pkgPath, "utf-8");
  } catch {
    return { exists: true, version: "" };
  }
  let parsed: unknown;
  try {
    parsed = JSON.parse(raw);
  } catch {
    fail(`${pkgPath} is not valid JSON. Fix the file before re-running /ship.`, 2);
  }
  const version = (parsed as { version?: unknown })?.version;
  return { exists: true, version: typeof version === "string" ? version : "" };
}

function writePkgVersion(pkgPath: string, version: string): void {
  const raw = readFileSync(pkgPath, "utf-8");
  const parsed = JSON.parse(raw) as Record<string, unknown>;
  parsed.version = version;
  writeFileSync(pkgPath, JSON.stringify(parsed, null, 2) + "\n");
}

/**
 * npm records the package version twice in its lockfiles — top-level
 * `version` and, in lockfileVersion >= 2, `packages[""].version` (the entry
 * describing the root package itself) — and `npm install` keeps both in
 * step. Nothing else in a release does, so a lockfile left behind drifts one
 * field per bump until someone runs npm, dirtying the tree on the next
 * `npm install` far from the cause (#2567). Pure JSON edit: no npm spawn,
 * no dependency-tree churn.
 *
 * Synced ONLY when the file already exists — never created (gstack itself
 * is bun-only; decision pinned in the v1.67 fix-wave plan).
 * npm-shrinkwrap.json shares the format and, when present, is what npm
 * actually honors, so both names are covered. Returns the names synced.
 */
const NPM_LOCKFILES = ["package-lock.json", "npm-shrinkwrap.json"];
function syncNpmLockfiles(dir: string, version: string, root: string): string[] {
  const synced: string[] = [];
  for (const name of NPM_LOCKFILES) {
    const lockPath = join(dir, name);
    if (!existsSync(lockPath)) continue;
    // A lockfile that is a symlink out of the repo would make this write an
    // arbitrary-file overwrite (same class as the version-path pin escape).
    // Skip with a warning — unlike the pins, a weird lockfile shouldn't
    // brick the whole bump.
    try {
      const realRoot = realpathSync(root);
      const realLock = realpathSync(lockPath);
      if (realLock !== realRoot && !realLock.startsWith(realRoot + sep)) {
        process.stderr.write(`WARNING: ${name} resolves outside the repository (symlink); not synced.\n`);
        continue;
      }
    } catch {
      continue;
    }
    const parsed = JSON.parse(readFileSync(lockPath, "utf-8")) as Record<string, unknown>;
    parsed.version = version;
    const packages = parsed.packages as Record<string, Record<string, unknown>> | undefined;
    if (packages && typeof packages[""] === "object" && packages[""] !== null) {
      packages[""].version = version;
    }
    writeFileSync(lockPath, JSON.stringify(parsed, null, 2) + "\n");
    synced.push(name);
  }
  return synced;
}

function baseVersion(cwd: string, base: string, versionRel: string): string {
  // Verify the base ref resolves, mirroring the Step 12 guard.
  try {
    execFileSync("git", ["rev-parse", "--verify", `origin/${base}`], { cwd, stdio: "ignore" });
  } catch {
    fail(`Unable to resolve origin/${base}. Run 'git fetch origin' or verify the base branch exists.`, 2);
  }
  try {
    const out = execFileSync("git", ["show", `origin/${base}:${versionRel}`], { cwd }).toString();
    return extractVersion(out, versionRel) || DEFAULT;
  } catch {
    // VERSION absent on base (new repo / new file) → treat as 0.0.0.0.
    return DEFAULT;
  }
}

/**
 * `expectedPkg` is what the manifest SHOULD hold for the current VERSION —
 * the npm-valid 3-digit translation (decision 11: npm rejects a fourth
 * component, so a correctly-synced `1.67.0` must not read as drift against
 * `1.67.0.0` forever). The historical 1:1 mirror (pre-v1.67 installs whose
 * package.json still carries the 4-digit form) is also accepted as in-sync;
 * write/repair migrate those to the translated form on the next release.
 */
function classifyState(
  current: string,
  base: string,
  pkgExists: boolean,
  pkgVersion: string,
  expectedPkg: string = current,
): State {
  const pkgAgrees =
    !pkgExists || !pkgVersion || pkgVersion === expectedPkg || pkgVersion === current;
  if (current === base) {
    // VERSION unchanged vs base. A diverging package.json means someone hand-edited
    // package.json bypassing /ship — unsafe to guess which is authoritative.
    if (!pkgAgrees) return "DRIFT_UNEXPECTED";
    return "FRESH";
  }
  // VERSION already moved past base.
  if (!pkgAgrees) return "DRIFT_STALE_PKG";
  return "ALREADY_BUMPED";
}

function cmdClassify(args: string[], cwd: string): void {
  const base = argVal(args, "--base");
  if (!base) fail("classify requires --base <branch>", 2);
  const versionRel = resolveVersionRel(cwd, argVal(args, "--version-path"));
  const versionPath = join(cwd, versionRel);
  const current = readVersionFile(versionPath, versionRel);
  const baseV = baseVersion(cwd, base!, versionRel);
  // When the version-path IS a package.json (#2501), that file is the single
  // source of truth and the "VERSION vs package.json" drift states cannot
  // arise — they are the same file. Reporting it as its own pkg keeps DRIFT_*
  // out of the classification instead of inventing a disagreement between a
  // file and itself.
  const jsonSource = isJsonVersionPath(versionRel);
  const pkgPath = jsonSource ? versionPath : resolvePkgPath(cwd, argVal(args, "--package-json-path"));
  const pkg = jsonSource
    ? { exists: existsSync(versionPath), version: current === DEFAULT ? "" : current }
    : readPkgVersion(pkgPath);
  // Decision 11: the manifest carries the npm-valid 3-digit translation of
  // the 4-digit VERSION; drift is judged against the translated form. A
  // JSON version-path is its own source of truth, so its expected form is
  // the version itself.
  const expectedPkg = jsonSource ? current : npmVersion(current);
  const state = classifyState(current, baseV, pkg.exists, pkg.version, expectedPkg);
  // Surface version-file absence so callers (and /ship) can tell "version is
  // genuinely 0.0.0.0" from "we made up 0.0.0.0 because the file is missing"
  // (#2600). Without this, the DRIFT_STALE_PKG dispatch on a missing VERSION
  // would feed repair a fabricated version that passes the shape check.
  const versionFileExists = existsSync(versionPath);
  process.stdout.write(
    JSON.stringify({
      state,
      baseVersion: baseV,
      currentVersion: current,
      pkgVersion: pkg.version || null,
      pkgExists: pkg.exists,
      pkgPath: pkg.exists ? relative(cwd, pkgPath) : null,
      expectedPkgVersion: pkg.exists ? expectedPkg : null,
      versionFileExists,
    }) + "\n",
  );
  // DRIFT_UNEXPECTED is a real, decidable state — the caller stops on it, but the
  // classification itself succeeded, so exit 0. (Bad args / unresolvable base are
  // the only exit-2 cases.)
}

function cmdWrite(args: string[], cwd: string): void {
  const version = argVal(args, "--version");
  if (!version) fail("write requires --version <X.Y.Z.W>", 2);
  if (!VERSION_RE.test(version!)) {
    fail(`NEW_VERSION (${version}) does not match MAJOR.MINOR.PATCH[.MICRO]. Aborting.`, 2);
  }
  const versionRel = resolveVersionRel(cwd, argVal(args, "--version-path"));
  const versionPath = join(cwd, versionRel);

  // A package.json version-path (#2501) is written in place, keeping the rest
  // of the file intact — and it is the ONLY file written. Also syncing a root
  // package.json here would be a guess about which of two JSON files the repo
  // actually publishes from; in a monorepo whose truth is frontend/package.json
  // the root one either doesn't exist or isn't the version users see.
  if (isJsonVersionPath(versionRel)) {
    if (!existsSync(versionPath)) {
      fail(`write: ${versionRel} does not exist. Check --version-path / .gstack/version-path.`, 2);
    }
    // Decision 11: a JSON manifest can only carry npm-valid semver. A repo
    // whose package.json still mirrors the legacy 4-digit form and pins it as
    // the version-path would otherwise get "1.67.0.1" written into a manifest
    // npm rejects forever — with no drift state to catch it (a JSON source is
    // self-consistent by construction).
    const jsonV = npmVersion(version!);
    let manifestWritten = false;
    let lockSynced: string[] = [];
    try {
      writeFileSync(versionPath, setVersionInJson(readFileSync(versionPath, "utf-8"), jsonV));
      manifestWritten = true;
      // The pinned manifest's OWN lockfiles (beside it) stay in step too.
      lockSynced = syncNpmLockfiles(dirname(versionPath), jsonV, cwd);
    } catch {
      fail(
        manifestWritten
          ? `write: ${versionRel} was updated but its npm lockfiles were not (corrupt lockfile?). ` +
            "Fix or delete the lockfile beside it, then re-run write with the same --version."
          : `write: failed to update ${versionRel} (is it valid JSON?).`,
        3,
      );
    }
    if (jsonV !== version) {
      process.stderr.write(
        `write: ${versionRel} carries the npm-valid translation ${jsonV} (a JSON manifest cannot hold 4-digit ${version}). ` +
          "Consecutive MICRO releases translate to the SAME manifest version — pin a plain VERSION file if that matters.\n",
      );
    }
    process.stdout.write(
      JSON.stringify({
        wrote: jsonV,
        // Only surfaced when a 4-digit request was translated (the healthy
        // 3-digit-pinned path is an identity write).
        ...(jsonV !== version ? { requestedVersion: version } : {}),
        versionPath: versionRel,
        packageJson: true,
        packageLock: lockSynced.length > 0,
      }) + "\n",
    );
    return;
  }

  const pkgPath = resolvePkgPath(cwd, argVal(args, "--package-json-path"));
  const hasPkg = existsSync(pkgPath);
  writeFileSync(versionPath, version + "\n");
  let lockSynced: string[] = [];
  // Decision 11: the manifest (and its lockfiles) carry the npm-valid
  // 3-digit translation — npm rejects a fourth component, so mirroring the
  // raw 4-digit form breaks `npm ci` in any repo npm actually manages.
  // VERSION keeps the full 4-digit form; it stays the source of truth.
  const manifestV = npmVersion(version!);
  if (hasPkg) {
    let pkgWritten = false;
    try {
      writePkgVersion(pkgPath, manifestV);
      pkgWritten = true;
      lockSynced = syncNpmLockfiles(dirname(pkgPath), manifestV, cwd);
    } catch {
      // Accurate recovery per failure point: classify only reads
      // package.json (never lockfiles), so "re-run and repair" is only true
      // when package.json itself is the stale file.
      fail(
        pkgWritten
          ? `VERSION and ${relative(cwd, pkgPath)} were written but the npm lockfiles were not ` +
            "(corrupt lockfile?). classify cannot see lockfile drift — fix or delete the lockfile, " +
            "then re-run write with the same --version."
          : `failed to update ${relative(cwd, pkgPath)}. VERSION was written but package.json is now ` +
            "stale. Re-run — classify will report DRIFT_STALE_PKG and repair will sync it.",
        3,
      );
    }
  }
  process.stdout.write(
    JSON.stringify({
      wrote: version,
      packageJson: hasPkg,
      packageJsonPath: hasPkg ? relative(cwd, pkgPath) : null,
      packageJsonVersion: hasPkg ? manifestV : null,
      packageLock: lockSynced.length > 0,
    }) + "\n",
  );
}

function cmdRepair(args: string[], cwd: string): void {
  const versionRel = resolveVersionRel(cwd, argVal(args, "--version-path"));
  const versionPath = join(cwd, versionRel);
  // Nothing to repair when the version lives in a package.json (#2501): there
  // is no second file to drift from, and classify never reports DRIFT_* for
  // that shape.
  if (isJsonVersionPath(versionRel)) {
    process.stdout.write(
      JSON.stringify({ repaired: null, reason: `${versionRel} is the single source of truth; no drift possible` }) + "\n",
    );
    return;
  }
  // Guard: if the VERSION file does not exist, readVersionFile folds that into
  // DEFAULT ("0.0.0.0") — a structurally valid but fabricated version. The
  // shape check below (VERSION_RE) would pass it, and we would write 0.0.0
  // into package.json, regressing it below where it started (#2600).
  if (!existsSync(versionPath)) {
    fail(
      `VERSION file not found at ${versionRel}. ` +
        "Cannot repair package.json without a real version to sync. " +
        "Pass --version-path or set .gstack/version-path if the file lives elsewhere.",
      2,
    );
  }
  const current = readVersionFile(versionPath, versionRel);
  // Guard against readVersionFile folding "file exists but is empty / unparsable"
  // into DEFAULT ("0.0.0.0") — same data-corruption pathway as file-missing (#2600).
  // A fabricated version must never propagate into package.json. But DEFAULT is
  // ambiguous: a VERSION file that GENUINELY reads "0.0.0.0" (a brand-new repo)
  // is a legitimate version, not the sentinel. Disambiguate on the raw bytes:
  // if the trimmed file content itself matches the version shape, proceed with
  // the repair; reject only when the raw content is empty or unparseable.
  if (current === DEFAULT) {
    let rawTrimmed = "";
    try {
      rawTrimmed = readFileSync(versionPath, "utf-8").trim();
    } catch {
      rawTrimmed = "";
    }
    if (!VERSION_RE.test(rawTrimmed)) {
      fail(
        `VERSION file at ${versionRel} is empty or contains no parsable version. ` +
          "Cannot repair package.json with a fabricated version.",
        2,
      );
    }
  }
  if (!VERSION_RE.test(current)) {
    fail(
      `VERSION file contents (${current}) do not match MAJOR.MINOR.PATCH[.MICRO]. ` +
        "Refusing to propagate invalid semver into package.json. Fix VERSION, then re-run /ship.",
      2,
    );
  }
  const pkgPath = resolvePkgPath(cwd, argVal(args, "--package-json-path"));
  if (!existsSync(pkgPath)) {
    fail(`repair: no package.json to sync (looked at ${relative(cwd, pkgPath)}).`, 2);
  }
  // Decision 11: repair syncs the manifest + lockfiles to the npm-valid
  // 3-digit translation of the current VERSION.
  const manifestV = npmVersion(current);
  try {
    writePkgVersion(pkgPath, manifestV);
    syncNpmLockfiles(dirname(pkgPath), manifestV, cwd);
  } catch {
    fail("drift repair failed — could not update package.json/npm lockfiles.", 3);
  }
  process.stdout.write(
    JSON.stringify({
      repaired: current,
      packageJsonPath: relative(cwd, pkgPath),
      packageJsonVersion: manifestV,
    }) + "\n",
  );
}

// Exported for unit tests (pure logic, no I/O).
export { classifyState, VERSION_RE, type State };

if (import.meta.main) {
  const [sub, ...rest] = process.argv.slice(2);
  const cwd = process.cwd();
  switch (sub) {
    case "classify": cmdClassify(rest, cwd); break;
    case "write": cmdWrite(rest, cwd); break;
    case "repair": cmdRepair(rest, cwd); break;
    default:
      fail("usage: gstack-version-bump <classify|write|repair> [flags]", 2);
  }
}