/**
 * Unit tests for SGX DCAP attestation.
 *
 * Mirrors the Python suite in ../nomyo/test/test_attestation.py: a mock router
 * serves /pki/attestation with a quote whose report_data is the real
 * SHA-512(server_pubkey_der [|| challenge]) binding, and a "faithful" verifier
 * decodes that quote back into a VerifiedQuote.
 */

import {
    AttestationPolicy,
    SgxAttestationVerifier,
    CallableQuoteVerifier,
    JwtQuoteVerifier,
} from '../../src/core/attestation';
import { VerifiedQuote } from '../../src/types/attestation';
import { AttestationError, SecurityError } from '../../src/errors';
import { SecureCompletionClient } from '../../src/core/SecureCompletionClient';
import { RSAOperations } from '../../src/core/crypto/rsa';
import {
    bytesToHex,
    hexToBytes,
    constantTimeEqual,
    sha512,
    stringToArrayBuffer,
    arrayBufferToBase64,
    arrayBufferToString,
} from '../../src/core/crypto/utils';

// ---- fixtures --------------------------------------------------------------

const MRENCLAVE = 'a'.repeat(64);
const MRSIGNER = 'b'.repeat(64);

interface HttpResponseLike {
    statusCode: number;
    headers: Record<string, string>;
    body: ArrayBuffer;
}

function jsonResponse(statusCode: number, body: object): HttpResponseLike {
    return {
        statusCode,
        headers: { 'content-type': 'application/json' },
        body: stringToArrayBuffer(JSON.stringify(body)),
    };
}

/**
 * Mock router: serves the server public key and an attestation quote binding
 * that key (plus any challenge) via SHA-512, exactly as the real enclave does.
 */
class MockServer {
    pubkeyPem!: string;
    pubkeyDer!: ArrayBuffer;

    /** Overrides for negative-path tests */
    isAvailable = true;
    reason = 'sgx not supported';
    bindToWrongKey = false;
    mrenclave = MRENCLAVE;
    mrsigner = MRSIGNER;
    isvProdId = 1;
    isvSvn = 3;
    tcbStatus = 'UpToDate';

    /** Challenges observed on /pki/attestation */
    seenChallenges: (string | null)[] = [];
    attestationCalls = 0;

    async init(): Promise<void> {
        const rsa = new RSAOperations();
        const pair = await rsa.generateKeyPair(2048);
        this.pubkeyPem = await rsa.exportPublicKey(pair.publicKey);
        this.pubkeyDer = await rsa.exportPublicKeyDer(pair.publicKey);
    }

    /**
     * The quote is opaque to the orchestrator; we encode the claims a real DCAP
     * verifier would recover from it, so `faithfulVerify` can play that role.
     */
    private async quoteB64(challenge: Uint8Array): Promise<string> {
        const keyBytes = this.bindToWrongKey
            ? new Uint8Array(this.pubkeyDer.byteLength).fill(0x41)
            : new Uint8Array(this.pubkeyDer);

        const bound = new Uint8Array(keyBytes.length + challenge.length);
        bound.set(keyBytes, 0);
        bound.set(challenge, keyBytes.length);
        const reportData = new Uint8Array(await sha512(bound));

        const claims = {
            mrenclave: this.mrenclave,
            mrsigner: this.mrsigner,
            isv_prod_id: this.isvProdId,
            isv_svn: this.isvSvn,
            tcb_status: this.tcbStatus,
            report_data: bytesToHex(reportData),
        };
        return arrayBufferToBase64(stringToArrayBuffer(JSON.stringify(claims)));
    }

    /** Drop-in replacement for the HttpClient interface. */
    client() {
        const handler = async (url: string): Promise<HttpResponseLike> => {
            const parsed = new URL(url);

            if (parsed.pathname === '/pki/public_key') {
                return {
                    statusCode: 200,
                    headers: {},
                    body: stringToArrayBuffer(this.pubkeyPem),
                };
            }

            if (parsed.pathname === '/pki/attestation') {
                this.attestationCalls += 1;
                const challengeHex = parsed.searchParams.get('challenge');
                this.seenChallenges.push(challengeHex);

                if (!this.isAvailable) {
                    return jsonResponse(200, { is_available: false, reason: this.reason });
                }
                const challenge = challengeHex ? hexToBytes(challengeHex) : new Uint8Array(0);
                return jsonResponse(200, {
                    is_available: true,
                    quote_b64: await this.quoteB64(challenge),
                });
            }

            return jsonResponse(404, { detail: 'not found' });
        };

        return {
            get: jest.fn((url: string) => handler(url)),
            post: jest.fn((url: string) => handler(url)),
        };
    }
}

/** Plays the role of a real DCAP verifier: recovers claims from the quote. */
async function faithfulVerify(quote: Uint8Array): Promise<VerifiedQuote> {
    const claims = JSON.parse(arrayBufferToString(quote.buffer as ArrayBuffer)) as Record<string, unknown>;
    return {
        mrenclave: String(claims.mrenclave),
        mrsigner: String(claims.mrsigner),
        isvProdId: Number(claims.isv_prod_id),
        isvSvn: Number(claims.isv_svn),
        tcbStatus: String(claims.tcb_status),
        reportData: hexToBytes(String(claims.report_data)),
    };
}

function makeOrchestrator(server: MockServer, policy: AttestationPolicy): SgxAttestationVerifier {
    const orchestrator = new SgxAttestationVerifier({
        routerUrl: 'https://router.test',
        policy,
        verifier: new CallableQuoteVerifier(faithfulVerify),
    });
    (orchestrator as unknown as { httpClient: unknown }).httpClient = server.client();
    return orchestrator;
}

/** Run the §3 algorithm against the mock server at the "high" tier. */
async function ensure(
    server: MockServer,
    policy: AttestationPolicy,
    tier = 'high'
): Promise<VerifiedQuote | null> {
    return makeOrchestrator(server, policy).ensureVerified(server.pubkeyDer, tier);
}

let server: MockServer;
let warnSpy: jest.SpyInstance;

beforeEach(async () => {
    server = new MockServer();
    await server.init();
    warnSpy = jest.spyOn(console, 'warn').mockImplementation(() => undefined);
});

afterEach(() => {
    warnSpy.mockRestore();
});

// ---- crypto helpers --------------------------------------------------------

describe('crypto helpers', () => {
    test('hex round-trips', () => {
        const bytes = new Uint8Array([0x00, 0x0f, 0xff, 0xa5]);
        expect(bytesToHex(bytes)).toBe('000fffa5');
        expect(Array.from(hexToBytes('000fffa5'))).toEqual(Array.from(bytes));
    });

    test('hexToBytes rejects malformed input', () => {
        expect(() => hexToBytes('abc')).toThrow('odd length');
        expect(() => hexToBytes('zzzz')).toThrow('non-hex');
    });

    test('constantTimeEqual compares correctly', () => {
        expect(constantTimeEqual(new Uint8Array([1, 2, 3]), new Uint8Array([1, 2, 3]))).toBe(true);
        expect(constantTimeEqual(new Uint8Array([1, 2, 3]), new Uint8Array([1, 2, 4]))).toBe(false);
        expect(constantTimeEqual(new Uint8Array([1, 2]), new Uint8Array([1, 2, 3]))).toBe(false);
    });
});

// ---- policy ----------------------------------------------------------------

describe('AttestationPolicy', () => {
    test('normalises pins to lowercase and applies defaults', () => {
        const policy = new AttestationPolicy({
            pinnedMrenclave: ['ABCDEF'],
            pinnedMrsigner: 'FEDCBA',
        });
        expect(policy.pinnedMrenclave.has('abcdef')).toBe(true);
        expect(policy.pinnedMrsigner).toBe('fedcba');
        expect(Array.from(policy.allowedTcbStatuses)).toEqual(['UpToDate']);
        expect(policy.requireAttestationForTier.has('high')).toBe(true);
        expect(policy.requireAttestationForTier.has('maximum')).toBe(true);
        expect(policy.enforce).toBe(false);
        expect(policy.liveness).toBe(false);
    });
});

// ---- orchestrator §3 algorithm ---------------------------------------------

describe('SgxAttestationVerifier', () => {
    test('happy path returns the verified quote', async () => {
        const policy = new AttestationPolicy({
            pinnedMrenclave: [MRENCLAVE],
            enforce: true,
        });
        const v = await ensure(server, policy);
        expect(v).not.toBeNull();
        expect(v!.mrenclave).toBe(MRENCLAVE);
        expect(v!.tcbStatus).toBe('UpToDate');
    });

    test('standard tier skips attestation entirely', async () => {
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        const v = await ensure(server, policy, 'standard');
        expect(v).toBeNull();
        expect(server.attestationCalls).toBe(0);
    });

    test('wrong key binding throws in enforce mode', async () => {
        server.bindToWrongKey = true;
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        await expect(ensure(server, policy)).rejects.toThrow(AttestationError);
        await expect(ensure(server, policy)).rejects.toThrow('key binding mismatch');
    });

    test('wrong key binding warns and proceeds when enforce is off', async () => {
        server.bindToWrongKey = true;
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: false });
        await expect(ensure(server, policy)).resolves.toBeNull();
        expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('key binding mismatch'));
    });

    test('MRENCLAVE outside the pinned set fails', async () => {
        server.mrenclave = 'c'.repeat(64);
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        await expect(ensure(server, policy)).rejects.toThrow('not in pinned set');
    });

    test('disallowed TCB status fails', async () => {
        server.tcbStatus = 'OutOfDate';
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        await expect(ensure(server, policy)).rejects.toThrow("TCB status 'OutOfDate' not in allowed");
    });

    test('MRSIGNER, prod id and SVN checks are enforced', async () => {
        const base = { pinnedMrenclave: [MRENCLAVE], enforce: true };

        await expect(
            ensure(server, new AttestationPolicy({ ...base, pinnedMrsigner: 'd'.repeat(64) }))
        ).rejects.toThrow('MRSIGNER');

        await expect(
            ensure(server, new AttestationPolicy({ ...base, pinnedProdId: 99 }))
        ).rejects.toThrow('isvProdId');

        await expect(
            ensure(server, new AttestationPolicy({ ...base, minIsvSvn: 10 }))
        ).rejects.toThrow('isvSvn 3 < minimum 10');

        // All satisfied
        await expect(
            ensure(server, new AttestationPolicy({
                ...base,
                pinnedMrsigner: MRSIGNER.toUpperCase(),
                pinnedProdId: 1,
                minIsvSvn: 3,
            }))
        ).resolves.not.toBeNull();
    });

    test('warns when no MRENCLAVE is pinned', async () => {
        await ensure(server, new AttestationPolicy({ enforce: true }));
        expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('enclave identity is NOT verified'));
    });

    test('unavailable attestation throws in enforce mode', async () => {
        server.isAvailable = false;
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        await expect(ensure(server, policy)).rejects.toThrow('attestation unavailable: sgx not supported');
    });

    test('unavailable attestation warns and proceeds when enforce is off', async () => {
        server.isAvailable = false;
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE] });
        await expect(ensure(server, policy)).resolves.toBeNull();
        expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('attestation unavailable'));
    });

    test('missing quote verifier throws in enforce mode', async () => {
        const orchestrator = new SgxAttestationVerifier({
            routerUrl: 'https://router.test',
            policy: new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true }),
        });
        (orchestrator as unknown as { httpClient: unknown }).httpClient = server.client();

        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high'))
            .rejects.toThrow('no quote verifier configured');
    });

    test('liveness sends a fresh challenge and binds to it', async () => {
        const policy = new AttestationPolicy({
            pinnedMrenclave: [MRENCLAVE],
            enforce: true,
            liveness: true,
        });
        const orchestrator = makeOrchestrator(server, policy);

        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high')).resolves.not.toBeNull();
        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high')).resolves.not.toBeNull();

        // Cache bypassed: both calls hit the server with distinct 32-byte challenges
        expect(server.attestationCalls).toBe(2);
        expect(server.seenChallenges).toHaveLength(2);
        expect(server.seenChallenges[0]).toHaveLength(64);
        expect(server.seenChallenges[0]).not.toBe(server.seenChallenges[1]);
    });

    test('session cache skips the second verification', async () => {
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        const orchestrator = makeOrchestrator(server, policy);

        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high')).resolves.not.toBeNull();
        // Second call is served from the session cache (null, no network)
        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high')).resolves.toBeNull();
        expect(server.attestationCalls).toBe(1);
        expect(server.seenChallenges[0]).toBeNull();
    });

    test('refuses to fetch attestation over plain HTTP', async () => {
        const orchestrator = new SgxAttestationVerifier({
            routerUrl: 'http://router.test',
            policy: new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE] }),
            verifier: new CallableQuoteVerifier(faithfulVerify),
        });
        (orchestrator as unknown as { httpClient: unknown }).httpClient = server.client();

        // Throws regardless of enforce — a MITM-able channel defeats attestation
        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high'))
            .rejects.toThrow('must be fetched over HTTPS');
    });

    test('allows plain HTTP when explicitly opted in', async () => {
        const orchestrator = new SgxAttestationVerifier({
            routerUrl: 'http://router.test',
            policy: new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true }),
            verifier: new CallableQuoteVerifier(faithfulVerify),
            allowHttp: true,
        });
        (orchestrator as unknown as { httpClient: unknown }).httpClient = server.client();

        await expect(orchestrator.ensureVerified(server.pubkeyDer, 'high')).resolves.not.toBeNull();
    });

    test('AttestationError is a SecurityError', async () => {
        server.isAvailable = false;
        const policy = new AttestationPolicy({ pinnedMrenclave: [MRENCLAVE], enforce: true });
        await expect(ensure(server, policy)).rejects.toBeInstanceOf(SecurityError);
    });
});

// ---- verifiers -------------------------------------------------------------

describe('CallableQuoteVerifier', () => {
    test('accepts a sync callable', async () => {
        const quote: VerifiedQuote = {
            mrenclave: MRENCLAVE,
            mrsigner: MRSIGNER,
            isvProdId: 1,
            isvSvn: 1,
            tcbStatus: 'UpToDate',
            reportData: new Uint8Array(64),
        };
        await expect(new CallableQuoteVerifier(() => quote).verify(new Uint8Array(0)))
            .resolves.toEqual(quote);
    });

    test('rejects a callable that returns the wrong shape', async () => {
        const bad = new CallableQuoteVerifier(() => ({ mrenclave: 'x' } as unknown as VerifiedQuote));
        await expect(bad.verify(new Uint8Array(0)))
            .rejects.toThrow('must return a VerifiedQuote');
    });
});

describe('JwtQuoteVerifier', () => {
    test('throws a helpful AttestationError when jose is not installed', async () => {
        const verifier = new JwtQuoteVerifier('https://verify.test/quote', 'https://verify.test/jwks');
        await expect(verifier.verify(new Uint8Array([1, 2, 3])))
            .rejects.toThrow(/requires the 'jose' package/);
    });

    test('accepts an injected jose module (CommonJS + ESM-only jose)', async () => {
        const claims = {
            sgx_mrenclave: MRENCLAVE.toUpperCase(),
            sgx_mrsigner: MRSIGNER,
            sgx_isvprodid: 1,
            sgx_isvsvn: '4',
            tcb_status: 'UpToDate',
            sgx_report_data: bytesToHex(new Uint8Array(64).fill(7)),
        };
        const jose = {
            createRemoteJWKSet: jest.fn(() => ({ kid: 'stub' })),
            jwtVerify: jest.fn(async () => ({ payload: claims })),
        };

        const verifier = new JwtQuoteVerifier(
            'https://verify.test/quote',
            'https://verify.test/jwks',
            { jose, issuer: 'https://verify.test', algorithms: ['ES256'] }
        );
        (verifier as unknown as { httpClient: unknown }).httpClient = {
            post: jest.fn(async () => jsonResponse(200, { token: 'header.payload.sig' })),
            get: jest.fn(),
        };

        const v = await verifier.verify(new Uint8Array([1, 2, 3]));

        expect(v.mrenclave).toBe(MRENCLAVE);       // normalised to lowercase
        expect(v.isvSvn).toBe(4);                  // string claim coerced to int
        expect(v.reportData).toHaveLength(64);
        expect(jose.jwtVerify).toHaveBeenCalledWith(
            'header.payload.sig',
            expect.anything(),
            expect.objectContaining({ issuer: 'https://verify.test', algorithms: ['ES256'] })
        );
    });

    test('rejects a verifier response without a token', async () => {
        const verifier = new JwtQuoteVerifier('https://verify.test/quote', 'https://verify.test/jwks', {
            jose: { createRemoteJWKSet: jest.fn(), jwtVerify: jest.fn() },
        });
        (verifier as unknown as { httpClient: unknown }).httpClient = {
            post: jest.fn(async () => jsonResponse(200, { nope: true })),
            get: jest.fn(),
        };

        await expect(verifier.verify(new Uint8Array([1]))).rejects.toThrow("missing JWT 'token'");
    });

    test('surfaces a non-200 from the verification service', async () => {
        const verifier = new JwtQuoteVerifier('https://verify.test/quote', 'https://verify.test/jwks', {
            jose: { createRemoteJWKSet: jest.fn(), jwtVerify: jest.fn() },
        });
        (verifier as unknown as { httpClient: unknown }).httpClient = {
            post: jest.fn(async () => jsonResponse(503, { detail: 'down' })),
            get: jest.fn(),
        };

        await expect(verifier.verify(new Uint8Array([1]))).rejects.toThrow('returned HTTP 503');
    });
});

// ---- end-to-end through SecureCompletionClient ------------------------------

describe('SecureCompletionClient with attestation', () => {
    test('enforce failure never sends plaintext', async () => {
        server.bindToWrongKey = true;

        const client = new SecureCompletionClient({
            routerUrl: 'https://router.test',
            keyRotationInterval: 0,
            keySize: 2048,
            attestationPolicy: new AttestationPolicy({
                pinnedMrenclave: [MRENCLAVE],
                enforce: true,
            }),
            quoteVerifier: new CallableQuoteVerifier(faithfulVerify),
        });

        const http = server.client();
        (client as unknown as { httpClient: unknown }).httpClient = http;
        (client as unknown as { attestation: { httpClient: unknown } }).attestation.httpClient = http;

        await expect(
            client.sendSecureRequest({ model: 'm', messages: [] }, 'pid', undefined, 'high')
        ).rejects.toThrow(AttestationError);

        // The completion endpoint was never POSTed to
        expect(http.post).not.toHaveBeenCalled();
        client.dispose();
    });

    test('no attestation configured leaves behaviour unchanged', async () => {
        const client = new SecureCompletionClient({
            routerUrl: 'https://router.test',
            keyRotationInterval: 0,
            keySize: 2048,
        });
        expect((client as unknown as { attestation?: unknown }).attestation).toBeUndefined();

        const http = server.client();
        (client as unknown as { httpClient: unknown }).httpClient = http;

        // Reaches the router (mock returns 404 for the completion endpoint) —
        // i.e. no attestation step ran and no attestation request was made.
        await expect(
            client.sendSecureRequest({ model: 'm', messages: [] }, 'pid', undefined, 'high')
        ).rejects.toThrow('Endpoint not found');
        expect(server.attestationCalls).toBe(0);
        client.dispose();
    });
});