#!/usr/bin/env node
/**
 * Pre-commit guard: refuses the commit if docs/work/_system/_state.json is staged
 * but is not byte-identical to what `pnpm work rebuild-state` would emit
 * given the current markdown content of docs/work/.
 *
 * Run from .husky/pre-commit AFTER lint-staged and AFTER the conditional
 * rebuild-state + re-stage step. By that point the staged _state.json
 * should already match the rebuild output. This script is the safety net
 * for the case where someone hand-edits _state.json without going through
 * rebuild-state.
 *
 * Exit codes:
 *   0 — _state.json is in sync (or not staged at all)
 *   1 — _state.json is staged but out of sync
 */
import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { execSync } from "node:child_process";
import { buildState } from "./state-builder.mjs";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const REPO_ROOT = path.resolve(__dirname, "..", "..");
const WORK_ROOT = path.join(REPO_ROOT, "docs", "work");
const STATE_FILE = path.join(WORK_ROOT, "_system", "_state.json");

function stagedFiles() {
  const out = execSync("git diff --cached --name-only", {
    cwd: REPO_ROOT,
    encoding: "utf8",
  });
  return out.split("\n").filter(Boolean);
}

function main() {
  const staged = stagedFiles();
  const stateRel = path.relative(REPO_ROOT, STATE_FILE);
  if (
    !staged.includes(stateRel) &&
    !staged.some((f) => f.startsWith("docs/work/") && f.endsWith(".md"))
  ) {
    process.exit(0);
  }
  if (!fs.existsSync(STATE_FILE)) {
    console.error(
      "✗ state-sync-guard: docs/work/_system/_state.json missing. Run `pnpm work rebuild-state`.",
    );
    process.exit(1);
  }
  const onDisk = fs.readFileSync(STATE_FILE, "utf8");
  const fresh = JSON.stringify(buildState(WORK_ROOT), null, 2) + "\n";
  // The `updated_at` timestamp will always differ. Strip it from both sides
  // before comparing.
  const stripUpdatedAt = (s) =>
    s.replace(/"updated_at":\s*"[^"]+",?\s*\n?/, "");
  if (stripUpdatedAt(onDisk) === stripUpdatedAt(fresh)) {
    process.exit(0);
  }
  console.error(
    "✗ state-sync-guard: docs/work/_system/_state.json is out of sync with markdown.",
  );
  console.error("   Run: pnpm work rebuild-state");
  console.error("   Then: git add docs/work/_system/_state.json");
  process.exit(1);
}

main();
