/* eslint-env mocha */
'use strict'

const expect = require('chai').expect
const Buffer = require('safe-buffer').Buffer

const secp256k1 = require('../src')
const crypto = require('../src/crypto')
const libp2pCrypto = require('libp2p-crypto')
const pbm = libp2pCrypto.protobuf
const randomBytes = libp2pCrypto.randomBytes

describe('secp256k1 keys', () => {
  let key
  before((done) => {
    secp256k1.generateKeyPair((err, _key) => {
      if (err) return done(err)
      key = _key
      done()
    })
  })

  it('generates a valid key', (done) => {
    expect(
      key
    ).to.be.an.instanceof(
      secp256k1.Secp256k1PrivateKey
    )
    expect(
      key.public
    ).to.be.an.instanceof(
      secp256k1.Secp256k1PublicKey
    )

    key.hash((err, digest) => {
      if (err) return done(err)

      expect(digest).to.have.length(34)

      key.public.hash((err, digest) => {
        if (err) return done(err)

        expect(digest).to.have.length(34)
        done()
      })
    })
  })

  it('optionally accepts a `bits` argument when generating a key', (done) => {
    secp256k1.generateKeyPair(256, (err, _key) => {
      expect(err).to.not.exist
      expect(_key).to.be.an.instanceof(secp256k1.Secp256k1PrivateKey)
      done()
    })
  })

  it('requires a callback to generate a key', (done) => {
    expect(() =>
      secp256k1.generateKeyPair()
    ).to.throw()
    done()
  })

  it('signs', (done) => {
    const text = randomBytes(512)

    key.sign(text, (err, sig) => {
      if (err) {
        return done(err)
      }

      key.public.verify(text, sig, (err, res) => {
        if (err) {
          return done(err)
        }

        expect(res).to.be.eql(true)
        done()
      })
    })
  })

  it('encoding', (done) => {
    const keyMarshal = key.marshal()
    secp256k1.unmarshalSecp256k1PrivateKey(keyMarshal, (err, key2) => {
      if (err) {
        return done(err)
      }
      const keyMarshal2 = key2.marshal()

      expect(
        keyMarshal
      ).to.be.eql(
        keyMarshal2
      )

      const pk = key.public
      const pkMarshal = pk.marshal()
      const pk2 = secp256k1.unmarshalSecp256k1PublicKey(pkMarshal)
      const pkMarshal2 = pk2.marshal()

      expect(
        pkMarshal
      ).to.be.eql(
        pkMarshal2
      )
      done()
    })
  })

  describe('key equals', () => {
    it('equals itself', () => {
      expect(
        key.equals(key)
      ).to.be.eql(
        true
      )

      expect(
        key.public.equals(key.public)
      ).to.be.eql(
        true
      )
    })

    it('not equals other key', (done) => {
      secp256k1.generateKeyPair(256, (err, key2) => {
        if (err) return done(err)

        expect(
          key.equals(key2)
        ).to.be.eql(
          false
        )

        expect(
          key2.equals(key)
        ).to.be.eql(
          false
        )

        expect(
          key.public.equals(key2.public)
        ).to.be.eql(
          false
        )

        expect(
          key2.public.equals(key.public)
        ).to.be.eql(
          false
        )
        done()
      })
    })
  })

  it('sign and verify', (done) => {
    const data = Buffer.from('hello world')
    key.sign(data, (err, sig) => {
      if (err) {
        return done(err)
      }

      key.public.verify(data, sig, (err, valid) => {
        if (err) {
          return done(err)
        }
        expect(valid).to.be.eql(true)
        done()
      })
    })
  })

  it('fails to verify for different data', (done) => {
    const data = Buffer.from('hello world')
    key.sign(data, (err, sig) => {
      if (err) {
        return done(err)
      }

      key.public.verify(Buffer.from('hello'), sig, (err, valid) => {
        if (err) {
          return done(err)
        }
        expect(valid).to.be.eql(false)
        done()
      })
    })
  })
})

describe('key generation error', () => {
  let generateKey

  before((done) => {
    generateKey = crypto.generateKey
    crypto.generateKey = (callback) => { callback(new Error('Error generating key')) }
    done()
  })

  after((done) => {
    crypto.generateKey = generateKey
    done()
  })

  it('returns an error if key generation fails', (done) => {
    secp256k1.generateKeyPair((err, key) => {
      expect(err).to.exist
      expect(key).to.not.exist
      done()
    })
  })
})

describe('handles generation of invalid key', () => {
  let generateKey

  before((done) => {
    generateKey = crypto.generateKey
    crypto.generateKey = (callback) => { callback(null, Buffer.from('not a real key')) }
    done()
  })

  after((done) => {
    crypto.generateKey = generateKey
    done()
  })

  it('returns an error if key generator returns an invalid key', (done) => {
    secp256k1.generateKeyPair((err, key) => {
      expect(err).to.exist
      expect(key).to.not.exist
      done()
    })
  })
})

describe('crypto functions', () => {
  let privKey, pubKey

  before((done) => {
    crypto.generateKey((err, _key) => {
      if (err) return done(err)
      privKey = _key
      pubKey = crypto.computePublicKey(privKey)
      done()
    })
  })

  it('generates valid keys', (done) => {
    expect(() => {
      crypto.validatePrivateKey(privKey)
      crypto.validatePublicKey(pubKey)
    }).to.not.throw()
    done()
  })

  it('does not validate an invalid key', (done) => {
    expect(() => {
      crypto.validatePublicKey(Buffer.from('42'))
    }).to.throw()

    expect(() => {
      crypto.validatePrivateKey(Buffer.from('42'))
    }).to.throw()
    done()
  })

  it('validates a correct signature', (done) => {
    crypto.hashAndSign(privKey, Buffer.from('hello'), (err, sig) => {
      if (err) return done(err)
      crypto.hashAndVerify(pubKey, sig, Buffer.from('hello'), (err, valid) => {
        if (err) return done(err)
        expect(valid).to.be.eql(true)
        done()
      })
    })
  })

  it('errors if given a null buffer to sign', (done) => {
    crypto.hashAndSign(privKey, null, (err, sig) => {
      expect(err).to.exist
      expect(sig).to.not.exist
      done()
    })
  })

  it('errors when signing with an invalid key', (done) => {
    crypto.hashAndSign(Buffer.from('42'), Buffer.from('Hello'), (err, sig) => {
      expect(err).to.exist
      expect(sig).to.not.exist
      done()
    })
  })

  it('errors if given a null buffer to validate', (done) => {
    crypto.hashAndSign(privKey, Buffer.from('hello'), (err, sig) => {
      if (err) return done(err)

      crypto.hashAndVerify(privKey, sig, null, (err, valid) => {
        expect(err).to.exist
        expect(valid).to.not.exist
        done()
      })
    })
  })

  it('errors when validating a message with an invalid signature', (done) => {
    crypto.hashAndVerify(pubKey, Buffer.from('invalid-sig'), Buffer.from('hello'), (err, valid) => {
      expect(err).to.exist
      expect(valid).to.not.exist
      done()
    })
  })

  it('errors when signing with an invalid key', (done) => {
    crypto.hashAndSign(Buffer.from('42'), Buffer.from('Hello'), (err, sig) => {
      expect(err).to.exist
      expect(sig).to.not.exist
      done()
    })
  })

  it('throws when compressing an invalid public key', (done) => {
    expect(() => {
      crypto.compressPublicKey(Buffer.from('42'))
    }).to.throw()
    done()
  })

  it('throws when decompressing an invalid public key', (done) => {
    expect(() => {
      crypto.decompressPublicKey(Buffer.from('42'))
    }).to.throw()
    done()
  })

  it('compresses/decompresses a valid public key', (done) => {
    const decompressed = crypto.decompressPublicKey(pubKey)
    expect(decompressed).to.exist
    expect(decompressed.length).to.be.eql(65)
    const recompressed = crypto.compressPublicKey(decompressed)
    expect(recompressed).to.be.eql(pubKey)
    done()
  })
})

describe('go interop', () => {
  const fixtures = require('./fixtures/go-interop')

  it('loads a private key marshaled by go-libp2p-crypto', (done) => {
    // we need to first extract the key data from the protobuf, which is
    // normally handled by js-libp2p-crypto
    const decoded = pbm.PrivateKey.decode(fixtures.privateKey)
    expect(decoded.Type).to.be.eql(pbm.KeyType.Secp256k1)

    secp256k1.unmarshalSecp256k1PrivateKey(decoded.Data, (err, key) => {
      if (err) return done(err)

      expect(key).to.be.an.instanceof(secp256k1.Secp256k1PrivateKey)
      expect(key.bytes).to.be.eql(fixtures.privateKey)
      done()
    })
  })

  it('loads a public key marshaled by go-libp2p-crypto', (done) => {
    const decoded = pbm.PublicKey.decode(fixtures.publicKey)
    expect(decoded.Type).to.be.eql(pbm.KeyType.Secp256k1)

    const key = secp256k1.unmarshalSecp256k1PublicKey(decoded.Data)
    expect(key).to.be.an.instanceof(secp256k1.Secp256k1PublicKey)
    expect(key.bytes).to.be.eql(fixtures.publicKey)
    done()
  })

  it('generates the same signature as go-libp2p-crypto', (done) => {
    const decoded = pbm.PrivateKey.decode(fixtures.privateKey)
    expect(decoded.Type).to.be.eql(pbm.KeyType.Secp256k1)

    secp256k1.unmarshalSecp256k1PrivateKey(decoded.Data, (err, key) => {
      if (err) return done(err)

      key.sign(fixtures.message, (err, sig) => {
        if (err) return done(err)
        expect(sig).to.be.eql(fixtures.signature)
        done()
      })
    })
  })
})