import assert from 'assert'
import { randomBytes } from 'crypto'
import LRUCache from 'lru-cache'
import ms from 'ms'
import chalk from 'chalk'
import * as rlp from 'rlp'
import Common from '@ethereumjs/common'
import { Transaction } from '@ethereumjs/tx'
import { Block, BlockHeader } from '@ethereumjs/block'
import * as devp2p from '../src/index'
import { ETH, Peer } from '../src/index'

const PRIVATE_KEY = randomBytes(32)

const common = new Common({ chain: 'mainnet' })
const bootstrapNodes = common.bootstrapNodes()
const BOOTNODES = bootstrapNodes.map((node: any) => {
  return {
    address: node.ip,
    udpPort: node.port,
    tcpPort: node.port
  }
})
const REMOTE_CLIENTID_FILTER = [
  'go1.5',
  'go1.6',
  'go1.7',
  'quorum',
  'pirl',
  'ubiq',
  'gmc',
  'gwhale',
  'prichain'
]

const CHECK_BLOCK_TITLE = 'Byzantium Fork' // Only for debugging/console output
const CHECK_BLOCK_NR = 4370000
const CHECK_BLOCK = 'b1fcff633029ee18ab6482b58ff8b6e95dd7c82a954c852157152a7a6d32785e'
const CHECK_BLOCK_HEADER = rlp.decode(
  Buffer.from(
    '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',
    'hex'
  )
)

const getPeerAddr = (peer: Peer) => `${peer._socket.remoteAddress}:${peer._socket.remotePort}`

// DPT
const dpt = new devp2p.DPT(PRIVATE_KEY, {
  refreshInterval: 30000,
  endpoint: {
    address: '0.0.0.0',
    udpPort: null,
    tcpPort: null
  }
})

/* eslint-disable no-console */
dpt.on('error', err => console.error(chalk.red(`DPT error: ${err}`)))

/* eslint-disable @typescript-eslint/no-use-before-define */

// RLPx
const rlpx = new devp2p.RLPx(PRIVATE_KEY, {
  dpt: dpt,
  maxPeers: 25,
  capabilities: [devp2p.ETH.eth64],
  common: common,
  remoteClientIdFilter: REMOTE_CLIENTID_FILTER,
  listenPort: null
})

rlpx.on('error', err => console.error(chalk.red(`RLPx error: ${err.stack || err}`)))

rlpx.on('peer:added', peer => {
  const addr = getPeerAddr(peer)
  const eth = peer.getProtocols()[0]
  const requests: {
    headers: any[]
    bodies: any[]
    msgTypes: { [key: string]: ETH.MESSAGE_CODES }
  } = { headers: [], bodies: [], msgTypes: {} }

  const clientId = peer.getHelloMessage().clientId
  console.log(
    chalk.green(
      `Add peer: ${addr} ${clientId} (eth${eth.getVersion()}) (total: ${rlpx.getPeers().length})`
    )
  )

  eth.sendStatus({
    td: devp2p.int2buffer(17179869184), // total difficulty in genesis block
    bestHash: Buffer.from(
      'd4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3',
      'hex'
    ),
    genesisHash: Buffer.from(
      'd4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3',
      'hex'
    )
  })

  // check CHECK_BLOCK
  let forkDrop: NodeJS.Timeout
  let forkVerified = false
  eth.once('status', () => {
    eth.sendMessage(devp2p.ETH.MESSAGE_CODES.GET_BLOCK_HEADERS, [CHECK_BLOCK_NR, 1, 0, 0])
    forkDrop = setTimeout(() => {
      peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
    }, ms('15s'))
    peer.once('close', () => clearTimeout(forkDrop))
  })

  eth.on('message', async (code: ETH.MESSAGE_CODES, payload: any) => {
    if (code in ETH.MESSAGE_CODES) {
      requests.msgTypes[code] = code + 1
    } else {
      requests.msgTypes[code] = 1
    }

    switch (code) {
      case devp2p.ETH.MESSAGE_CODES.NEW_BLOCK_HASHES:
        if (!forkVerified) break

        for (const item of payload) {
          const blockHash = item[0]
          if (blocksCache.has(blockHash.toString('hex'))) continue
          setTimeout(() => {
            eth.sendMessage(devp2p.ETH.MESSAGE_CODES.GET_BLOCK_HEADERS, [blockHash, 1, 0, 0])
            requests.headers.push(blockHash)
          }, ms('0.1s'))
        }
        break

      case devp2p.ETH.MESSAGE_CODES.TX:
        if (!forkVerified) break

        for (const item of payload) {
          const tx = Transaction.fromValuesArray(item)
          if (isValidTx(tx)) onNewTx(tx, peer)
        }

        break

      case devp2p.ETH.MESSAGE_CODES.GET_BLOCK_HEADERS: {
        const headers = []
        // hack
        if (devp2p.buffer2int(payload[0]) === CHECK_BLOCK_NR) {
          headers.push(CHECK_BLOCK_HEADER)
        }

        if (requests.headers.length === 0 && requests.msgTypes[code] >= 8) {
          peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
        } else {
          eth.sendMessage(devp2p.ETH.MESSAGE_CODES.BLOCK_HEADERS, headers)
        }
        break
      }

      case devp2p.ETH.MESSAGE_CODES.BLOCK_HEADERS: {
        if (!forkVerified) {
          if (payload.length !== 1) {
            console.log(
              `${addr} expected one header for ${CHECK_BLOCK_TITLE} verify (received: ${payload.length})`
            )
            peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
            break
          }

          const expectedHash = CHECK_BLOCK
          const header = BlockHeader.fromValuesArray(payload[0], {})
          if (header.hash().toString('hex') === expectedHash) {
            console.log(`${addr} verified to be on the same side of the ${CHECK_BLOCK_TITLE}`)
            clearTimeout(forkDrop)
            forkVerified = true
          }
        } else {
          if (payload.length > 1) {
            console.log(
              `${addr} not more than one block header expected (received: ${payload.length})`
            )
            break
          }

          let isValidPayload = false
          const header = BlockHeader.fromValuesArray(payload[0], {})
          while (requests.headers.length > 0) {
            const blockHash = requests.headers.shift()
            if (header.hash().equals(blockHash)) {
              isValidPayload = true
              setTimeout(() => {
                eth.sendMessage(devp2p.ETH.MESSAGE_CODES.GET_BLOCK_BODIES, [blockHash])
                requests.bodies.push(header)
              }, ms('0.1s'))
              break
            }
          }

          if (!isValidPayload) {
            console.log(`${addr} received wrong block header ${header.hash().toString('hex')}`)
          }
        }

        break
      }

      case devp2p.ETH.MESSAGE_CODES.GET_BLOCK_BODIES:
        if (requests.headers.length === 0 && requests.msgTypes[code] >= 8) {
          peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
        } else {
          eth.sendMessage(devp2p.ETH.MESSAGE_CODES.BLOCK_BODIES, [])
        }
        break

      case devp2p.ETH.MESSAGE_CODES.BLOCK_BODIES: {
        if (!forkVerified) break

        if (payload.length !== 1) {
          console.log(`${addr} not more than one block body expected (received: ${payload.length})`)
          break
        }

        let isValidPayload = false
        while (requests.bodies.length > 0) {
          const header = requests.bodies.shift()
          const txs = payload[0][0]
          const uncleHeaders = payload[0][1]
          const block = Block.fromValuesArray([header.raw(), txs, uncleHeaders])
          const isValid = await isValidBlock(block)
          if (isValid) {
            isValidPayload = true
            onNewBlock(block, peer)
            break
          }
        }

        if (!isValidPayload) {
          console.log(`${addr} received wrong block body`)
        }

        break
      }

      case devp2p.ETH.MESSAGE_CODES.NEW_BLOCK: {
        if (!forkVerified) break

        const newBlock = Block.fromValuesArray(payload[0])
        const isValidNewBlock = await isValidBlock(newBlock)
        if (isValidNewBlock) onNewBlock(newBlock, peer)

        break
      }

      case devp2p.ETH.MESSAGE_CODES.GET_NODE_DATA:
        if (requests.headers.length === 0 && requests.msgTypes[code] >= 8) {
          peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
        } else {
          eth.sendMessage(devp2p.ETH.MESSAGE_CODES.NODE_DATA, [])
        }
        break

      case devp2p.ETH.MESSAGE_CODES.NODE_DATA:
        break

      case devp2p.ETH.MESSAGE_CODES.GET_RECEIPTS:
        if (requests.headers.length === 0 && requests.msgTypes[code] >= 8) {
          peer.disconnect(devp2p.DISCONNECT_REASONS.USELESS_PEER)
        } else {
          eth.sendMessage(devp2p.ETH.MESSAGE_CODES.RECEIPTS, [])
        }
        break

      case devp2p.ETH.MESSAGE_CODES.RECEIPTS:
        break
    }
  })
})

rlpx.on('peer:removed', (peer, reasonCode, disconnectWe) => {
  const who = disconnectWe ? 'we disconnect' : 'peer disconnect'
  const total = rlpx.getPeers().length
  console.log(
    chalk.yellow(
      `Remove peer: ${getPeerAddr(peer)} - ${who}, reason: ${peer.getDisconnectPrefix(
        reasonCode
      )} (${String(reasonCode)}) (total: ${total})`
    )
  )
})

rlpx.on('peer:error', (peer, err) => {
  if (err.code === 'ECONNRESET') return

  if (err instanceof assert.AssertionError) {
    const peerId = peer.getId()
    if (peerId !== null) dpt.banPeer(peerId, ms('5m'))

    console.error(chalk.red(`Peer error (${getPeerAddr(peer)}): ${err.message}`))
    return
  }

  console.error(chalk.red(`Peer error (${getPeerAddr(peer)}): ${err.stack || err}`))
})

// uncomment, if you want accept incoming connections
// rlpx.listen(30303, '0.0.0.0')
// dpt.bind(30303, '0.0.0.0')

for (const bootnode of BOOTNODES) {
  dpt.bootstrap(bootnode).catch(err => {
    console.error(chalk.bold.red(`DPT bootstrap error: ${err.stack || err}`))
  })
}

// connect to local ethereum node (debug)
/*
dpt.addPeer({ address: '127.0.0.1', udpPort: 30303, tcpPort: 30303 })
  .then((peer) => {
    return rlpx.connect({
      id: peer.id,
      address: peer.address,
      port: peer.tcpPort
    })
  })
  .catch((err) => console.log(`error on connection to local node: ${err.stack || err}`))
*/

const txCache = new LRUCache({ max: 1000 })
function onNewTx(tx: Transaction, peer: Peer) {
  const txHashHex = tx.hash().toString('hex')
  if (txCache.has(txHashHex)) return

  txCache.set(txHashHex, true)
  console.log(`New tx: ${txHashHex} (from ${getPeerAddr(peer)})`)
}

const blocksCache = new LRUCache({ max: 100 })
function onNewBlock(block: Block, peer: Peer) {
  const blockHashHex = block.hash().toString('hex')
  const blockNumber = block.header.number.toNumber()
  if (blocksCache.has(blockHashHex)) return

  blocksCache.set(blockHashHex, true)
  console.log(
    `----------------------------------------------------------------------------------------------------------`
  )
  console.log(`New block ${blockNumber}: ${blockHashHex} (from ${getPeerAddr(peer)})`)
  console.log(
    `----------------------------------------------------------------------------------------------------------`
  )
  for (const tx of block.transactions) onNewTx(tx, peer)
}

function isValidTx(tx: Transaction) {
  return tx.validate()
}

async function isValidBlock(block: Block) {
  return (
    block.validateUnclesHash() &&
    block.transactions.every(isValidTx) &&
    block.validateTransactionsTrie()
  )
}

setInterval(() => {
  const peersCount = dpt.getPeers().length
  const openSlots = rlpx._getOpenSlots()
  const queueLength = rlpx._peersQueue.length
  const queueLength2 = rlpx._peersQueue.filter(o => o.ts <= Date.now()).length

  console.log(
    chalk.yellow(
      `Total nodes in DPT: ${peersCount}, open slots: ${openSlots}, queue: ${queueLength} / ${queueLength2}`
    )
  )
}, ms('30s'))