#!/usr/bin/env bun
/**
 * Generate cross-platform test vectors from the TypeScript implementation.
 *
 * The output JSON files are loaded by BOTH the TypeScript and Kotlin test
 * suites. Any divergence between platforms fails CI immediately.
 *
 * Usage: bun run scripts/generate-vectors.ts
 */
import { writeFileSync } from 'fs';
import { join } from 'path';
import { SubtleCryptoProvider, MemoryStorage } from '../packages/shade-crypto-web/src/index.js';
import { computeFingerprint } from '../packages/shade-core/src/fingerprint.js';
import { kdfChainKey, kdfRootKey, deriveInitialRootKey } from '../packages/shade-core/src/keys.js';
import { encodeEnvelope, decodeEnvelope } from '../packages/shade-proto/src/index.js';
import type { ShadeEnvelope, RatchetMessage } from '../packages/shade-core/src/index.js';

const crypto = new SubtleCryptoProvider();
const OUT_DIR = join(import.meta.dir, '..', 'test-vectors');

function hex(bytes: Uint8Array): string {
  return Array.from(bytes, (b) => b.toString(16).padStart(2, '0')).join('');
}

function fromHex(str: string): Uint8Array {
  const bytes = new Uint8Array(str.length / 2);
  for (let i = 0; i < bytes.length; i++) {
    bytes[i] = parseInt(str.substring(i * 2, i * 2 + 2), 16);
  }
  return bytes;
}

interface Vector {
  description: string;
  [key: string]: any;
}

// ─── HKDF vectors ───────────────────────────────────────────
async function generateHkdfVectors(): Promise<Vector[]> {
  const vectors: Vector[] = [];

  // Known inputs → expected outputs
  const cases = [
    { ikm: '01'.repeat(32), salt: '02'.repeat(32), info: 'test', length: 32 },
    { ikm: 'ab'.repeat(32), salt: '00'.repeat(32), info: 'ShadeRootRatchet', length: 64 },
    { ikm: 'cd'.repeat(32), salt: '00'.repeat(32), info: 'ShadeX3DH', length: 32 },
  ];

  for (const c of cases) {
    const out = await crypto.hkdf(
      fromHex(c.ikm),
      fromHex(c.salt),
      new TextEncoder().encode(c.info),
      c.length,
    );
    vectors.push({
      description: `HKDF-SHA256 with ikm=${c.ikm.slice(0, 8)}... info="${c.info}"`,
      ikm: c.ikm,
      salt: c.salt,
      info: c.info,
      length: c.length,
      output: hex(out),
    });
  }

  return vectors;
}

// ─── KDF chain vectors ─────────────────────────────────────
async function generateKdfChainVectors(): Promise<Vector[]> {
  const rootKey = new Uint8Array(32).fill(0x11);
  const dhOutput = new Uint8Array(32).fill(0x22);
  const rootResult = await kdfRootKey(crypto, rootKey, dhOutput);

  const chainKey = new Uint8Array(32).fill(0x33);
  const chainResult = await kdfChainKey(crypto, chainKey);

  return [
    {
      description: 'Root key ratchet: kdfRootKey',
      rootKey: hex(rootKey),
      dhOutput: hex(dhOutput),
      newRootKey: hex(rootResult.newRootKey),
      chainKey: hex(rootResult.chainKey),
    },
    {
      description: 'Chain key ratchet: kdfChainKey',
      chainKey: hex(chainKey),
      newChainKey: hex(chainResult.newChainKey),
      messageKey: hex(chainResult.messageKey),
    },
  ];
}

// ─── X3DH initial root key ─────────────────────────────────
async function generateX3DHVectors(): Promise<Vector[]> {
  const secrets = [
    new Uint8Array(32).fill(0xaa),
    new Uint8Array(32).fill(0xbb),
    new Uint8Array(32).fill(0xcc),
  ];
  const rootKey3 = await deriveInitialRootKey(crypto, secrets);

  const secrets4 = [...secrets, new Uint8Array(32).fill(0xdd)];
  const rootKey4 = await deriveInitialRootKey(crypto, secrets4);

  return [
    {
      description: 'X3DH initial root key with 3 DH outputs (no one-time prekey)',
      secrets: secrets.map(hex),
      rootKey: hex(rootKey3),
    },
    {
      description: 'X3DH initial root key with 4 DH outputs (with one-time prekey)',
      secrets: secrets4.map(hex),
      rootKey: hex(rootKey4),
    },
  ];
}

// ─── Fingerprint vectors ───────────────────────────────────
async function generateFingerprintVectors(): Promise<Vector[]> {
  const cases = [
    { sig: '01'.repeat(32), dh: '02'.repeat(32) },
    { sig: 'ab'.repeat(32), dh: 'cd'.repeat(32) },
  ];

  const vectors: Vector[] = [];
  for (const c of cases) {
    const fp = await computeFingerprint(crypto, fromHex(c.sig), fromHex(c.dh));
    vectors.push({
      description: `Fingerprint for signing=${c.sig.slice(0, 8)}... dh=${c.dh.slice(0, 8)}...`,
      signingKey: c.sig,
      dhKey: c.dh,
      fingerprint: fp,
    });
  }

  return vectors;
}

// ─── Wire format vectors ───────────────────────────────────
async function generateWireFormatVectors(): Promise<Vector[]> {
  // Deterministic inputs
  const ratchetMsg: RatchetMessage = {
    dhPublicKey: new Uint8Array(32).fill(0x11),
    previousCounter: 42,
    counter: 7,
    ciphertext: new Uint8Array(16).fill(0x22),
    nonce: new Uint8Array(12).fill(0x33),
  };

  const envelopeRatchet: ShadeEnvelope = {
    type: 'ratchet',
    content: ratchetMsg,
    timestamp: 0,
    senderAddress: '',
  };
  const bytesRatchet = encodeEnvelope(envelopeRatchet);

  return [
    {
      description: 'Wire format: RatchetMessage encoding',
      message: {
        dhPublicKey: hex(ratchetMsg.dhPublicKey),
        previousCounter: ratchetMsg.previousCounter,
        counter: ratchetMsg.counter,
        ciphertext: hex(ratchetMsg.ciphertext),
        nonce: hex(ratchetMsg.nonce),
      },
      encoded: hex(bytesRatchet),
    },
  ];
}

async function main() {
  console.log('Generating cross-platform test vectors…');

  const files: Array<[string, any]> = [
    ['hkdf.json', { vectors: await generateHkdfVectors() }],
    ['kdf-chain.json', { vectors: await generateKdfChainVectors() }],
    ['x3dh.json', { vectors: await generateX3DHVectors() }],
    ['fingerprint.json', { vectors: await generateFingerprintVectors() }],
    ['wire-format.json', { vectors: await generateWireFormatVectors() }],
  ];

  for (const [name, data] of files) {
    const path = join(OUT_DIR, name);
    writeFileSync(path, JSON.stringify(data, null, 2) + '\n');
    console.log(`  ✓ ${name} (${data.vectors.length} vectors)`);
  }

  console.log('Done.');
}

main().catch((err) => {
  console.error(err);
  process.exit(1);
});