#!/usr/bin/env node

import { createHash } from "node:crypto";
import { spawnSync } from "node:child_process";
import { copyFile, lstat, mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const scriptDir = dirname(fileURLToPath(import.meta.url));
const workspaceRoot = resolve(scriptDir, "../../..");
const engineRoot = resolve(
  process.env.NODEDC_ENGINE_SOURCE_ROOT || join(workspaceRoot, "NODEDC_ENGINE_INFRA"),
);
const artifactDir = resolve(
  process.env.NODEDC_DEPLOY_ARTIFACT_DIR || resolve(scriptDir, "../deploy-artifacts"),
);
const [patchId = "engine-mcp-l1-credential-reuse-20260724-043", ...extra] =
  process.argv.slice(2);

if (
  extra.length
  || !/^engine-mcp-l1-credential-reuse-\d{8}-\d{3}$/.test(patchId)
) {
  throw new Error(
    "usage: build-engine-mcp-l1-credential-reuse-artifact.mjs "
      + "[engine-mcp-l1-credential-reuse-YYYYMMDD-NNN]",
  );
}

const expectedSha256 = Object.freeze({
  "nodedc-source/server/routes/n8n.js":
    "6620e4bdd573e9f6b636a4b059eafef76d59da2fdb2183038fa5ec95357d8478",
  "nodedc-source/server/deployTransitions/l1CredentialReuseV1.json":
    "2ada49ef8bb2f146a9ea8d3c9ab5ee55f6a4e1b17e0f4b62a16f27368bd0eb05",
});
const files = Object.freeze(Object.keys(expectedSha256));
const artifact = join(artifactDir, `nodedc-${patchId}.tgz`);
const checksum = `${artifact}.sha256`;
const stage = await mkdtemp(join(tmpdir(), "nodedc-engine-l1-credential-reuse-"));

await assertFresh(artifact);
await assertExactSources();

try {
  for (const relativePath of files) {
    const destination = join(stage, "payload", relativePath);
    await mkdir(dirname(destination), { recursive: true });
    await copyFile(join(engineRoot, relativePath), destination);
  }
  await writeFile(
    join(stage, "manifest.env"),
    `id=${patchId}\ncomponent=engine\ntype=app-overlay\n`,
    "utf8",
  );
  await writeFile(join(stage, "files.txt"), `${files.join("\n")}\n`, "utf8");
  await mkdir(artifactDir, { recursive: true });
  run("python3", ["-c", canonicalTarScript(), artifact, stage]);
  const sha256 = digest(await readFile(artifact));
  await writeFile(checksum, `${sha256}  ${artifact.split("/").at(-1)}\n`, "utf8");
  console.log(JSON.stringify({
    ok: true,
    patchId,
    artifact,
    checksum,
    sha256,
    services: ["nodedc-backend"],
    mcpVersion: "0.11.0",
    tool: "engine_list_l2_credential_refs",
    credentialScope: "same-l1-workflow",
    crossL1Sharing: false,
    managedGrants: "target-local",
    credentialValuesIncluded: false,
    files,
  }, null, 2));
} finally {
  await rm(stage, { recursive: true, force: true });
}

async function assertExactSources() {
  for (const [relativePath, expected] of Object.entries(expectedSha256)) {
    const sourcePath = join(engineRoot, relativePath);
    const info = await lstat(sourcePath);
    if (!info.isFile() || info.isSymbolicLink()) {
      throw new Error(`engine_l1_credential_reuse_source_unsafe:${relativePath}`);
    }
    const actual = digest(await readFile(sourcePath));
    if (actual !== expected) {
      throw new Error(
        `engine_l1_credential_reuse_target_mismatch:${relativePath}:`
          + `expected=${expected}:actual=${actual}`,
      );
    }
  }

  const route = await readFile(
    join(engineRoot, "nodedc-source/server/routes/n8n.js"),
    "utf8",
  );
  const descriptor = JSON.parse(await readFile(
    join(
      engineRoot,
      "nodedc-source/server/deployTransitions/l1CredentialReuseV1.json",
    ),
    "utf8",
  ));
  if (
    !route.includes("function buildEngineAgentL1CredentialContext")
    || !route.includes("candidateScope === 'l1' ? l1Context.graph : graph")
    || !route.includes("managed writer/reader grants")
    || descriptor?.id !== "engine-mcp-l1-credential-reuse-v1"
    || descriptor?.visibilityProof?.scope !== "same-l1-workflow"
    || descriptor?.binding?.applyOperation !== "assignCredentialRef"
    || descriptor?.crossL1Sharing !== false
    || descriptor?.managedGrants !== "target-local"
  ) {
    throw new Error("engine_l1_credential_reuse_runtime_boundary_invalid");
  }
}

async function assertFresh(path) {
  try {
    await lstat(path);
  } catch (error) {
    if (error?.code === "ENOENT") return;
    throw error;
  }
  throw new Error("artifact_already_exists");
}

function canonicalTarScript() {
  return [
    "import gzip,io,pathlib,sys,tarfile",
    "root=pathlib.Path(sys.argv[2])",
    "with open(sys.argv[1],'xb') as out:",
    " with gzip.GzipFile(filename='',mode='wb',fileobj=out,compresslevel=9,mtime=0) as gz:",
    "  with tarfile.open(fileobj=gz,mode='w',format=tarfile.PAX_FORMAT) as tar:",
    "   for top in ('manifest.env','files.txt','payload'):",
    "    p=root/top; paths=[p]+(sorted(p.rglob('*')) if p.is_dir() else [])",
    "    for x in paths:",
    "     info=tar.gettarinfo(str(x),arcname=x.relative_to(root).as_posix())",
    "     info.uid=info.gid=0; info.uname=info.gname='root'; info.mtime=0; info.mode=0o755 if info.isdir() else 0o644",
    "     with (open(x,'rb') if info.isfile() else io.BytesIO()) as src: tar.addfile(info,src if info.isfile() else None)",
  ].join("\n");
}

function digest(value) {
  return createHash("sha256").update(value).digest("hex");
}

function run(command, args) {
  const result = spawnSync(command, args, {
    encoding: "utf8",
    maxBuffer: 128 * 1024 * 1024,
  });
  if (result.status !== 0) {
    throw new Error(`${command}_failed:${result.stderr || result.stdout}`);
  }
}
