#!/usr/bin/env node
import { createPublicKey } from "node:crypto";
import { readFile } from "node:fs/promises";
import { pathToFileURL } from "node:url";

import {
  APPROVAL_PROJECTION_ATTESTATION_SCHEMA,
  APPROVAL_PROJECTION_ATTESTATION_SCOPE,
  computeApprovalClosure,
} from "../../src/security/approval-closure.ts";
import {
  canonicalValueBytes,
  isSha256Hex,
  parseCanonicalJson,
} from "../../src/security/canonical-digest.ts";
import { computeProductionInputRoot } from "../../src/security/production-input-root.ts";

const expectedRequestFields = [
  "schema",
  "latestLedgerHeadHash",
  "latestLedgerRevision",
  "trustedKeys",
  "ledgerProof",
  "contentRecords",
  "assetRecords",
  "inputDigests",
].sort();
const expectedKeyFields = [
  "keyId",
  "issuerEpoch",
  "scope",
  "authorizedRoles",
  "publicKeyPem",
].sort();
const expectedInputs = [
  "PortfolioContent",
  "PreparedAssetSet",
  "PublicAssetManifest",
  "SiteConfig",
];

function exactObject(value, fields, label) {
  if (value === null || typeof value !== "object" || Array.isArray(value))
    throw new Error(`${label} must be an object.`);
  if (JSON.stringify(Object.keys(value).sort()) !== JSON.stringify(fields))
    throw new Error(`${label} contains missing or unknown fields.`);
  return value;
}

function requestPath(args) {
  if (args.length !== 2 || args[0] !== "--request" || args[1].length === 0)
    throw new Error(
      "Usage: verify-approvals.mjs --request <canonical-request.json>",
    );
  return args[1];
}

function verifyApprovalRequestAt(source, now) {
  const request = exactObject(
    parseCanonicalJson(source),
    expectedRequestFields,
    "request",
  );
  if (request.schema !== "portfolio-approval-verification-request/v1")
    throw new Error("Request schema is invalid.");
  if (
    !Array.isArray(request.trustedKeys) ||
    !Array.isArray(request.contentRecords) ||
    !Array.isArray(request.assetRecords)
  )
    throw new Error("Approval record lists are invalid.");
  const trustedKeys = request.trustedKeys.map((candidate) => {
    const key = exactObject(candidate, expectedKeyFields, "trusted key");
    if (
      key.scope !== "portfolio-approval-decision/v1" ||
      typeof key.keyId !== "string" ||
      !Number.isSafeInteger(key.issuerEpoch) ||
      !Array.isArray(key.authorizedRoles) ||
      key.authorizedRoles.some((role) => typeof role !== "string") ||
      typeof key.publicKeyPem !== "string"
    ) {
      throw new Error("Trusted approval key is invalid.");
    }
    return {
      keyId: key.keyId,
      issuerEpoch: key.issuerEpoch,
      scope: key.scope,
      authorizedRoles: key.authorizedRoles,
      publicKey: createPublicKey(key.publicKeyPem),
    };
  });
  const inputDigests = exactObject(
    request.inputDigests,
    expectedInputs,
    "inputDigests",
  );
  if (Object.values(inputDigests).some((digest) => !isSha256Hex(digest)))
    throw new Error("Input digest is invalid.");
  const closure = computeApprovalClosure({
    contentRecords: request.contentRecords,
    assetRecords: request.assetRecords,
    trust: {
      now,
      latestLedgerHeadHash: request.latestLedgerHeadHash,
      latestLedgerRevision: request.latestLedgerRevision,
      trustedKeys,
      ledgerProof: request.ledgerProof,
    },
  });
  const productionInputRoot = computeProductionInputRoot({
    portfolioContentDigest: inputDigests.PortfolioContent,
    publicAssetManifestDigest: inputDigests.PublicAssetManifest,
    preparedAssetSetDigest: inputDigests.PreparedAssetSet,
    siteConfigDigest: inputDigests.SiteConfig,
  });
  return {
    schema: "portfolio-approval-verification-result/v1",
    projectionSchema: APPROVAL_PROJECTION_ATTESTATION_SCHEMA,
    projectionScope: APPROVAL_PROJECTION_ATTESTATION_SCOPE,
    approvedRecordRoot: closure.approvedRecordRoot,
    approvedAssetRoot: closure.approvedAssetRoot,
    approvalProofSetDigest: closure.approvalProofSetDigest,
    productionInputRoot,
    latestLedgerHeadHash: request.latestLedgerHeadHash,
    latestLedgerRevision: request.latestLedgerRevision,
    earliestApprovalExpiry: closure.earliestApprovalExpiry,
  };
}

export function verifyApprovalRequest(source) {
  return verifyApprovalRequestAt(source, new Date().toISOString());
}

export function verifyApprovalRequestForTest(source, clock) {
  if (
    clock === null ||
    typeof clock !== "object" ||
    Object.keys(clock).length !== 1 ||
    typeof clock.now !== "string"
  ) {
    throw new Error("Test-only approval clock is invalid.");
  }
  return verifyApprovalRequestAt(source, clock.now);
}

async function main() {
  const path = requestPath(process.argv.slice(2));
  const result = verifyApprovalRequest(await readFile(path));
  process.stdout.write(Buffer.from(canonicalValueBytes(result)));
  process.stdout.write("\n");
}

if (
  process.argv[1] !== undefined &&
  import.meta.url === pathToFileURL(process.argv[1]).href
) {
  main().catch((error) => {
    const message =
      error instanceof Error ? error.message : "Unknown verification failure.";
    process.stderr.write(`Approval verification failed: ${message}\n`);
    process.exitCode = 1;
  });
}