/**
 * Generates src/generated/versionInfo.json with the project's current version,
 * git tag/describe info, and the last commit's metadata. Consumed by the admin
 * VersionOverlay via GET /api/version (the file is read at runtime so a fresh
 * post-bump regeneration rsync'd to the server shows up without a rebuild).
 *
 * Gracefully no-ops on missing git metadata (no .git, no tags) so the JSON
 * always exists with whatever fields are resolvable.
 */
import { execSync } from "node:child_process";
import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";

const here = path.dirname(fileURLToPath(import.meta.url));
const projectRoot = path.resolve(here, "..", "..");

function git(args: string): string | null {
  try {
    const out = execSync(`git ${args}`, { cwd: projectRoot, encoding: "utf8" });
    const trimmed = out.trim();
    return trimmed.length > 0 ? trimmed : null;
  } catch {
    return null;
  }
}

function readPackageVersion(): string | null {
  try {
    const pkg = JSON.parse(readFileSync(path.join(projectRoot, "package.json"), "utf8"));
    return typeof pkg?.version === "string" && pkg.version.length > 0 ? pkg.version : null;
  } catch {
    return null;
  }
}

function main(): void {
  const version = readPackageVersion();
  const tag = git("describe --tags --always --abbrev=0");
  const gitDescribe = git("describe --tags --always --abbrev=7");
  const commitHash = git("rev-parse --short HEAD");
  const commitDate = git("log -1 --format=%cI");
  const commitSubject = git("log -1 --format=%s");
  const buildTime = new Date().toISOString();

  const info = {
    version,
    tag,
    gitDescribe,
    commitHash,
    commitDate,
    commitSubject,
    buildTime,
  };

  const outDir = path.join(projectRoot, "src", "generated");
  if (!existsSync(outDir)) {
    mkdirSync(outDir, { recursive: true });
  }
  writeFileSync(
    path.join(outDir, "versionInfo.json"),
    `${JSON.stringify(info, null, 2)}\n`,
    "utf8",
  );

  const label = gitDescribe ?? tag ?? version ?? "unknown";
  console.log(`[version-info] wrote src/generated/versionInfo.json (${label})`);
}

main();