import { SDJWTException } from '@sd-jwt/utils';
import { Jwt } from '../jwt';
import Crypto from 'node:crypto';
import type { Signer, Verifier } from '@sd-jwt/types';
import { describe, expect, test } from 'vitest';

describe('JWT', () => {
  test('create', async () => {
    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });

    expect(jwt.header).toEqual({ alg: 'EdDSA' });
    expect(jwt.payload).toEqual({ foo: 'bar' });
  });

  test('returns decoded JWT when correct JWT string is provided', () => {
    // Two objects are created separately, the first: { alg: 'HS256', typ: 'JWT' } represents a JWT Header and the second: { sub: '1234567890', name: 'John Doe' } represents a JWT Payload.
    // These objects are turned into strings with JSON.stringify. The resulting strings are encoded with base64 encoding using Buffer.from(string).toString('base64').
    // These base64 encoded strings are concatenated with a period (.) between them, following the structure of a JWT, which is composed of three Base64-URL strings separated by dots (header.payload.signature).
    // A 'signature' string is added at the end to represent a JWT signature.
    // So, the jwt variable ends up being a string with the format of a base64Url encoded Header, a period, a base64Url encoded Payload, another period, and a 'signature' string.
    // It's important to note that the 'signature' here is just a placeholder string and not an actual cryptographic signature generated from the header and payload data.
    const jwt = `${Buffer.from(
      JSON.stringify({ alg: 'HS256', typ: 'JWT' }),
    ).toString('base64')}.${Buffer.from(
      JSON.stringify({ sub: '1234567890', name: 'John Doe' }),
    ).toString('base64')}.signature`;
    const result = Jwt.decodeJWT(jwt);
    expect(result).toEqual({
      header: { alg: 'HS256', typ: 'JWT' },
      payload: { sub: '1234567890', name: 'John Doe' },
      signature: 'signature',
    });
  });

  test('throws an error when JWT string is not correctly formed', () => {
    const jwt = 'abc.def';
    expect(() => Jwt.decodeJWT(jwt)).toThrow('Invalid JWT as input');
  });

  test('throws an error when JWT parts are missing', () => {
    const jwt = `${Buffer.from(
      JSON.stringify({ alg: 'HS256', typ: 'JWT' }),
    ).toString('base64')}`;
    expect(() => Jwt.decodeJWT(jwt)).toThrow('Invalid JWT as input');
  });

  test('set', async () => {
    const jwt = new Jwt();
    jwt.setHeader({ alg: 'EdDSA' });
    jwt.setPayload({ foo: 'bar' });

    expect(jwt.header).toEqual({ alg: 'EdDSA' });
    expect(jwt.payload).toEqual({ foo: 'bar' });
  });

  test('sign', async () => {
    const { privateKey } = Crypto.generateKeyPairSync('ed25519');
    const testSigner: Signer = async (data: string) => {
      const sig = Crypto.sign(null, Buffer.from(data), privateKey);
      return Buffer.from(sig).toString('base64url');
    };
    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });

    const encodedJwt = await jwt.sign(testSigner);
    expect(typeof encodedJwt).toBe('string');
  });

  test('verify', async () => {
    const { privateKey, publicKey } = Crypto.generateKeyPairSync('ed25519');
    const testSigner: Signer = async (data: string) => {
      const sig = Crypto.sign(null, Buffer.from(data), privateKey);
      return Buffer.from(sig).toString('base64url');
    };
    const testVerifier: Verifier = async (data: string, sig: string) => {
      return Crypto.verify(
        null,
        Buffer.from(data),
        publicKey,
        Buffer.from(sig, 'base64url'),
      );
    };

    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });

    const encodedJwt = await jwt.sign(testSigner);
    const newJwt = Jwt.fromEncode(encodedJwt);
    const verified = await newJwt.verify(testVerifier);
    expect(verified).toStrictEqual({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });
    try {
      await newJwt.verify(() => false);
    } catch (e: unknown) {
      expect(e).toBeInstanceOf(SDJWTException);
    }
  });

  test('encode', async () => {
    const { privateKey, publicKey } = Crypto.generateKeyPairSync('ed25519');
    const testSigner: Signer = async (data: string) => {
      const sig = Crypto.sign(null, Buffer.from(data), privateKey);
      return Buffer.from(sig).toString('base64url');
    };

    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });

    const encodedJwt = await jwt.sign(testSigner);
    const newJwt = Jwt.fromEncode(encodedJwt);
    const newEncodedJwt = newJwt.encodeJwt();
    expect(newEncodedJwt).toBe(encodedJwt);
  });

  test('decode failed', () => {
    expect(() => Jwt.fromEncode('asfasfas')).toThrow();
  });

  test('encode failed', async () => {
    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
    });

    try {
      jwt.encodeJwt();
    } catch (e: unknown) {
      expect(e).toBeInstanceOf(SDJWTException);
    }
  });

  test('getUnsignedToken failed', async () => {
    const { privateKey, publicKey } = Crypto.generateKeyPairSync('ed25519');
    const testSigner: Signer = async (data: string) => {
      const sig = Crypto.sign(null, Buffer.from(data), privateKey);
      return Buffer.from(sig).toString('base64url');
    };

    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
    });

    try {
      await jwt.sign(testSigner);
    } catch (e: unknown) {
      expect(e).toBeInstanceOf(SDJWTException);
    }
  });

  test('wrong encoded field', async () => {
    const { privateKey, publicKey } = Crypto.generateKeyPairSync('ed25519');
    const testSigner: Signer = async (data: string) => {
      const sig = Crypto.sign(null, Buffer.from(data), privateKey);
      return Buffer.from(sig).toString('base64url');
    };

    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
      encoded: 'asfasfafaf.dfasfafafasf', // it has to be 3 parts
    });

    try {
      await jwt.sign(testSigner);
    } catch (e: unknown) {
      expect(e).toBeInstanceOf(SDJWTException);
    }
  });

  test('verify failed no signature', async () => {
    const { privateKey, publicKey } = Crypto.generateKeyPairSync('ed25519');
    const testVerifier: Verifier = async (data: string, sig: string) => {
      return Crypto.verify(
        null,
        Buffer.from(data),
        publicKey,
        Buffer.from(sig, 'base64url'),
      );
    };

    const jwt = new Jwt({
      header: { alg: 'EdDSA' },
      payload: { foo: 'bar' },
    });

    try {
      await jwt.verify(testVerifier);
    } catch (e: unknown) {
      expect(e).toBeInstanceOf(SDJWTException);
    }
  });
});