/*
 * WHICH SERVER PACKAGE IS RUNNING — a LEAF module, importing nothing from
 * `tools/`.
 *
 * It lived in `transport.ts`, and `capabilities.ts` imported it from there. The
 * moment `status` needs to REPORT capabilities, that becomes
 * transport -> capabilities -> transport: a cycle, and the same one Task 9
 * produced when the kind registry sat inside `record-events.ts`. That one only
 * worked because `tools/index.ts` happened to import in the surviving order —
 * a load-ORDER dependency, invisible until something imported a module
 * directly, which is what a consumer or a test does.
 *
 * A cycle that works by luck is not a working cycle, so the shared fact moves
 * out rather than the edge being added on top of it.
 *
 * NOTE WHAT THIS REPORTS AND WHAT IT DOES NOT. `version` is the label in the
 * package.json this process loaded from — CONTEXT for a reader, never evidence
 * of a capability. A published tarball has already been observed carrying a
 * change its version said it could not. Capability questions are answered by
 * `capabilities`, which CALLS the code.
 */
import { existsSync, readFileSync } from "node:fs";
import { spawnSync } from "node:child_process";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { isGitRepo } from "./tools/scopes.js";

/** Running server package + optional git identity. `fromDir` is a test seam. */
export function resolveServerIdentity(fromDir?: string): {
  path: string;
  version: string;
  branch?: string;
  sha?: string;
} {
  const start = fromDir ?? path.dirname(fileURLToPath(import.meta.url));
  let dir = start;
  let pkgFile: string | undefined;
  for (let i = 0; i < 8; i++) {
    const candidate = path.join(dir, "package.json");
    if (existsSync(candidate)) {
      pkgFile = candidate;
      break;
    }
    const parent = path.dirname(dir);
    if (parent === dir) break;
    dir = parent;
  }
  const pkgPath = pkgFile ?? path.resolve(start, "..", "..", "package.json");
  const pkgDir = path.dirname(pkgPath);
  let version = "unknown";
  try {
    const raw = JSON.parse(readFileSync(pkgPath, "utf8")) as { version?: string };
    if (typeof raw.version === "string" && raw.version) version = raw.version;
  } catch {
    /* leave unknown — never invent a version */
  }

  const out: { path: string; version: string; branch?: string; sha?: string } = {
    path: pkgDir,
    version,
  };

  dir = pkgDir;
  let gitRoot: string | undefined;
  for (let i = 0; i < 10; i++) {
    if (existsSync(path.join(dir, ".git"))) {
      gitRoot = dir;
      break;
    }
    const parent = path.dirname(dir);
    if (parent === dir) break;
    dir = parent;
  }
  if (gitRoot && isGitRepo(gitRoot)) {
    const branch = spawnSync("git", ["-C", gitRoot, "rev-parse", "--abbrev-ref", "HEAD"], { encoding: "utf8" });
    const sha = spawnSync("git", ["-C", gitRoot, "rev-parse", "HEAD"], { encoding: "utf8" });
    const b = branch.status === 0 ? String(branch.stdout).trim() : "";
    const s = sha.status === 0 ? String(sha.stdout).trim() : "";
    if (b) out.branch = b;
    if (s) out.sha = s;
  }
  return out;
}