import Crypto from './crypto'

const crypto = new Crypto()

export const process = (payload, state) => new Promise(async (resolve, reject) => {
  const privateKeyJson = state.user.privateKey
  const privateKey = await crypto.importEncryptDecryptKey(privateKeyJson, 'jwk', ['decrypt', 'unwrapKey'])

  let sessionKey
  let signingKey

  const iv = await crypto.convertStringToArrayBufferView(payload.iv)
  const signature = await crypto.convertStringToArrayBufferView(payload.signature)
  const payloadBuffer = await crypto.convertStringToArrayBufferView(payload.payload)

  await new Promise((resolvePayload) => {
    payload.keys.forEach(async (key) => {
      try {
        sessionKey = await crypto.unwrapKey(
          'jwk',
          key.sessionKey,
          privateKey,
          {
            name: 'RSA-OAEP',
            hash: { name: 'SHA-1' },
          },
          { name: 'AES-CBC' },
          true,
          ['decrypt']
        )

        signingKey = await crypto.unwrapKey(
          'jwk',
          key.signingKey,
          privateKey,
          {
            name: 'RSA-OAEP',
            hash: { name: 'SHA-1' },
          },
          { name: 'HMAC', hash: { name: 'SHA-256' } },
          true,
          ['verify']
        )
        resolvePayload()
      } catch (e) { } // eslint-disable-line
    })
  })

  const verified = await crypto.verifyPayload(
    signature,
    payloadBuffer,
    signingKey
  )

  if (!verified) {
    reject()
    return
  }

  const decryptedPayload = await crypto.decryptMessage(
    payloadBuffer,
    sessionKey,
    iv
  )

  const payloadJson = JSON.parse(crypto.convertArrayBufferViewToString(new Uint8Array(decryptedPayload)))

  resolve(payloadJson)
})

export const prepare = (payload, state) => new Promise(async (resolve) => {
  const myUsername = state.user.username
  const myId = state.user.id

  const sessionKey = await crypto.createSecretKey()
  const signingKey = await crypto.createSigningKey()
  const iv = await crypto.crypto.getRandomValues(new Uint8Array(16))

  const jsonToSend = {
    ...payload,
    payload: {
      ...payload.payload,
      sender: myId,
      username: myUsername,
      text: encodeURI(payload.payload.text),
    },
  }

  const payloadBuffer = crypto.convertStringToArrayBufferView(JSON.stringify(jsonToSend))

  const encryptedPayload = await crypto.encryptMessage(payloadBuffer, sessionKey, iv)
  const payloadString = await crypto.convertArrayBufferViewToString(new Uint8Array(encryptedPayload))

  const signature = await crypto.signMessage(encryptedPayload, signingKey)

  const encryptedKeys = await Promise.all(state.room.members
    .map(async (member) => {
      const key = await crypto.importEncryptDecryptKey(member.publicKey)
      const enc = await Promise.all([
        crypto.wrapKey(sessionKey, key),
        crypto.wrapKey(signingKey, key),
      ])
      return {
        sessionKey: enc[0],
        signingKey: enc[1],
      }
    })
  )

  const ivString = await crypto.convertArrayBufferViewToString(new Uint8Array(iv))
  const signatureString = await crypto.convertArrayBufferViewToString(new Uint8Array(signature))

  resolve({
    toSend: {
      payload: payloadString,
      signature: signatureString,
      iv: ivString,
      keys: encryptedKeys,
    },
    original: jsonToSend,
  })
})