const { expectRevert } = require('@openzeppelin/test-helpers');
const { toEthSignedMessageHash } = require('../../helpers/sign');

const { expect } = require('chai');

const ECDSAMock = artifacts.require('ECDSAMock');

const TEST_MESSAGE = web3.utils.sha3('OpenZeppelin');
const WRONG_MESSAGE = web3.utils.sha3('Nope');
const NON_HASH_MESSAGE = '0x' + Buffer.from('abcd').toString('hex');

function to2098Format (signature) {
  const long = web3.utils.hexToBytes(signature);
  if (long.length !== 65) {
    throw new Error('invalid signature length (expected long format)');
  }
  if (long[32] >> 7 === 1) {
    throw new Error('invalid signature \'s\' value');
  }
  const short = long.slice(0, 64);
  short[32] |= (long[64] % 27) << 7; // set the first bit of the 32nd byte to the v parity bit
  return web3.utils.bytesToHex(short);
}

function from2098Format (signature) {
  const short = web3.utils.hexToBytes(signature);
  if (short.length !== 64) {
    throw new Error('invalid signature length (expected short format)');
  }
  short.push((short[32] >> 7) + 27);
  short[32] &= (1 << 7) - 1; // zero out the first bit of 1 the 32nd byte
  return web3.utils.bytesToHex(short);
}

function split (signature) {
  const raw = web3.utils.hexToBytes(signature);
  switch (raw.length) {
  case 64:
    return [
      web3.utils.bytesToHex(raw.slice(0, 32)), // r
      web3.utils.bytesToHex(raw.slice(32, 64)), // vs
    ];
  case 65:
    return [
      raw[64], // v
      web3.utils.bytesToHex(raw.slice(0, 32)), // r
      web3.utils.bytesToHex(raw.slice(32, 64)), // s
    ];
  default:
    expect.fail('Invalid siganture length, cannot split');
  }
}

contract('ECDSA', function (accounts) {
  const [ other ] = accounts;

  beforeEach(async function () {
    this.ecdsa = await ECDSAMock.new();
  });

  context('recover with invalid signature', function () {
    it('with short signature', async function () {
      await expectRevert(this.ecdsa.recover(TEST_MESSAGE, '0x1234'), 'ECDSA: invalid signature length');
    });

    it('with long signature', async function () {
      await expectRevert(
        // eslint-disable-next-line max-len
        this.ecdsa.recover(TEST_MESSAGE, '0x01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),
        'ECDSA: invalid signature length',
      );
    });
  });

  context('recover with valid signature', function () {
    context('using web3.eth.sign', function () {
      it('returns signer address with correct signature', async function () {
        // Create the signature
        const signature = await web3.eth.sign(TEST_MESSAGE, other);

        // Recover the signer address from the generated message and signature.
        expect(await this.ecdsa.recover(
          toEthSignedMessageHash(TEST_MESSAGE),
          signature,
        )).to.equal(other);
      });

      it('returns signer address with correct signature for arbitrary length message', async function () {
        // Create the signature
        const signature = await web3.eth.sign(NON_HASH_MESSAGE, other);

        // Recover the signer address from the generated message and signature.
        expect(await this.ecdsa.recover(
          toEthSignedMessageHash(NON_HASH_MESSAGE),
          signature,
        )).to.equal(other);
      });

      it('returns a different address', async function () {
        const signature = await web3.eth.sign(TEST_MESSAGE, other);
        expect(await this.ecdsa.recover(WRONG_MESSAGE, signature)).to.not.equal(other);
      });

      it('reverts with invalid signature', async function () {
        // eslint-disable-next-line max-len
        const signature = '0x332ce75a821c982f9127538858900d87d3ec1f9f737338ad67cad133fa48feff48e6fa0c18abc62e42820f05943e47af3e9fbe306ce74d64094bdf1691ee53e01c';
        await expectRevert(this.ecdsa.recover(TEST_MESSAGE, signature), 'ECDSA: invalid signature');
      });
    });

    context('with v0 signature', function () {
      // Signature generated outside ganache with method web3.eth.sign(signer, message)
      const signer = '0x2cc1166f6212628A0deEf2B33BEFB2187D35b86c';
      // eslint-disable-next-line max-len
      const signatureWithoutVersion = '0x5d99b6f7f6d1f73d1a26497f2b1c89b24c0993913f86e9a2d02cd69887d9c94f3c880358579d811b21dd1b7fd9bb01c1d81d10e69f0384e675c32b39643be892';

      it('reverts with 00 as version value', async function () {
        const version = '00';
        const signature = signatureWithoutVersion + version;
        await expectRevert(this.ecdsa.recover(TEST_MESSAGE, signature), 'ECDSA: invalid signature \'v\' value');
        await expectRevert(
          this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature)),
          'ECDSA: invalid signature \'v\' value',
        );
      });

      it('works with 27 as version value', async function () {
        const version = '1b'; // 27 = 1b.
        const signature = signatureWithoutVersion + version;
        expect(await this.ecdsa.recover(TEST_MESSAGE, signature)).to.equal(signer);
        expect(await this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature))).to.equal(signer);
        expect(await this.ecdsa.recover_r_vs(TEST_MESSAGE, ...split(to2098Format(signature)))).to.equal(signer);
      });

      it('reverts with wrong version', async function () {
        // The last two hex digits are the signature version.
        // The only valid values are 0, 1, 27 and 28.
        const version = '02';
        const signature = signatureWithoutVersion + version;
        await expectRevert(this.ecdsa.recover(TEST_MESSAGE, signature), 'ECDSA: invalid signature \'v\' value');
        await expectRevert(
          this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature)),
          'ECDSA: invalid signature \'v\' value',
        );
      });

      it('works with short EIP2098 format', async function () {
        const version = '1b'; // 27 = 1b.
        const signature = signatureWithoutVersion + version;
        expect(await this.ecdsa.recover(TEST_MESSAGE, to2098Format(signature))).to.equal(signer);
        expect(await this.ecdsa.recover(TEST_MESSAGE, from2098Format(to2098Format(signature)))).to.equal(signer);
      });
    });

    context('with v1 signature', function () {
      const signer = '0x1E318623aB09Fe6de3C9b8672098464Aeda9100E';
      // eslint-disable-next-line max-len
      const signatureWithoutVersion = '0x331fe75a821c982f9127538858900d87d3ec1f9f737338ad67cad133fa48feff48e6fa0c18abc62e42820f05943e47af3e9fbe306ce74d64094bdf1691ee53e0';

      it('reverts with 01 as version value', async function () {
        const version = '01';
        const signature = signatureWithoutVersion + version;
        await expectRevert(this.ecdsa.recover(TEST_MESSAGE, signature), 'ECDSA: invalid signature \'v\' value');
        await expectRevert(
          this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature)),
          'ECDSA: invalid signature \'v\' value',
        );
      });

      it('works with 28 as version value', async function () {
        const version = '1c'; // 28 = 1c.
        const signature = signatureWithoutVersion + version;
        expect(await this.ecdsa.recover(TEST_MESSAGE, signature)).to.equal(signer);
        expect(await this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature))).to.equal(signer);
        expect(await this.ecdsa.recover_r_vs(TEST_MESSAGE, ...split(to2098Format(signature)))).to.equal(signer);
      });

      it('reverts with wrong version', async function () {
        // The last two hex digits are the signature version.
        // The only valid values are 0, 1, 27 and 28.
        const version = '02';
        const signature = signatureWithoutVersion + version;
        await expectRevert(this.ecdsa.recover(TEST_MESSAGE, signature), 'ECDSA: invalid signature \'v\' value');
        await expectRevert(
          this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(signature)),
          'ECDSA: invalid signature \'v\' value',
        );
      });

      it('works with short EIP2098 format', async function () {
        const version = '1c'; // 27 = 1b.
        const signature = signatureWithoutVersion + version;
        expect(await this.ecdsa.recover(TEST_MESSAGE, to2098Format(signature))).to.equal(signer);
        expect(await this.ecdsa.recover(TEST_MESSAGE, from2098Format(to2098Format(signature)))).to.equal(signer);
      });
    });

    it('reverts with high-s value signature', async function () {
      const message = '0xb94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9';
      // eslint-disable-next-line max-len
      const highSSignature = '0xe742ff452d41413616a5bf43fe15dd88294e983d3d36206c2712f39083d638bde0a0fc89be718fbc1033e1d30d78be1c68081562ed2e97af876f286f3453231d1b';
      await expectRevert(this.ecdsa.recover(message, highSSignature), 'ECDSA: invalid signature \'s\' value');
      await expectRevert(
        this.ecdsa.recover_v_r_s(TEST_MESSAGE, ...split(highSSignature)),
        'ECDSA: invalid signature \'s\' value',
      );
      expect(() => to2098Format(highSSignature)).to.throw('invalid signature \'s\' value');
    });
  });

  context('toEthSignedMessageHash', function () {
    it('prefixes bytes32 data correctly', async function () {
      expect(await this.ecdsa.methods['toEthSignedMessageHash(bytes32)'](TEST_MESSAGE))
        .to.equal(toEthSignedMessageHash(TEST_MESSAGE));
    });

    it('prefixes dynamic length data correctly', async function () {
      expect(await this.ecdsa.methods['toEthSignedMessageHash(bytes)'](NON_HASH_MESSAGE))
        .to.equal(toEthSignedMessageHash(NON_HASH_MESSAGE));
    });
  });
});