'use strict'
import { Transaction } from '@ethereumjs/tx'
import { Block } from '@ethereumjs/block'
import { BN, bufferToHex, Address } from 'ethereumjs-util'
import { ExecutionContext } from './execution-context'
import { EventManager } from '../eventManager'

export class TxRunner {
  event
  executionContext
  _api
  blockNumber
  runAsync
  pendingTxs
  vmaccounts
  queusTxs
  blocks
  commonContext

  constructor (vmaccounts, api, executionContext) {
    this.event = new EventManager()
    // has a default for now for backwards compatability
    this.executionContext = executionContext || new ExecutionContext()
    this.commonContext = this.executionContext.vmObject().common
    this._api = api
    this.blockNumber = 0
    this.runAsync = true
    if (this.executionContext.isVM()) {
      // this.blockNumber = 1150000 // The VM is running in Homestead mode, which started at this block.
      this.blockNumber = 0 // The VM is running in Homestead mode, which started at this block.
      this.runAsync = false // We have to run like this cause the VM Event Manager does not support running multiple txs at the same time.
    }
    this.pendingTxs = {}
    this.vmaccounts = vmaccounts
    this.queusTxs = []
    this.blocks = []
  }

  rawRun (args, confirmationCb, gasEstimationForceSend, promptCb, cb) {
    let timestamp = Date.now()
    if (args.timestamp) {
      timestamp = args.timestamp
    }
    run(this, args, timestamp, confirmationCb, gasEstimationForceSend, promptCb, cb)
  }

  _executeTx (tx, gasPrice, api, promptCb, callback) {
    if (gasPrice) tx.gasPrice = this.executionContext.web3().utils.toHex(gasPrice)
    if (api.personalMode()) {
      promptCb(
        (value) => {
          this._sendTransaction(this.executionContext.web3().personal.sendTransaction, tx, value, callback)
        },
        () => {
          return callback('Canceled by user.')
        }
      )
    } else {
      this._sendTransaction(this.executionContext.web3().eth.sendTransaction, tx, null, callback)
    }
  }

  _sendTransaction (sendTx, tx, pass, callback) {
    const cb = (err, resp) => {
      if (err) {
        return callback(err, resp)
      }
      this.event.trigger('transactionBroadcasted', [resp])
      var listenOnResponse = () => {
        // eslint-disable-next-line no-async-promise-executor
        return new Promise(async (resolve, reject) => {
          const result = await tryTillReceiptAvailable(resp, this.executionContext)
          tx = await tryTillTxAvailable(resp, this.executionContext)
          resolve({
            result,
            tx,
            transactionHash: result ? result['transactionHash'] : null
          })
        })
      }
      listenOnResponse().then((txData) => { callback(null, txData) }).catch((error) => { callback(error) })
    }
    const args = pass !== null ? [tx, pass, cb] : [tx, cb]
    try {
      sendTx.apply({}, args)
    } catch (e) {
      return callback(`Send transaction failed: ${e.message} . if you use an injected provider, please check it is properly unlocked. `)
    }
  }

  execute (args, confirmationCb, gasEstimationForceSend, promptCb, callback) {
    let data = args.data
    if (data.slice(0, 2) !== '0x') {
      data = '0x' + data
    }

    if (!this.executionContext.isVM()) {
      return this.runInNode(args.from, args.to, data, args.value, args.gasLimit, args.useCall, confirmationCb, gasEstimationForceSend, promptCb, callback)
    }
    try {
      this.runInVm(args.from, args.to, data, args.value, args.gasLimit, args.useCall, args.timestamp, callback)
    } catch (e) {
      callback(e, null)
    }
  }

  runInVm (from, to, data, value, gasLimit, useCall, timestamp, callback) {
    const self = this
    const account = self.vmaccounts[from]
    if (!account) {
      return callback('Invalid account selected')
    }

    if (Number.isInteger(gasLimit)) {
      gasLimit = '0x' + gasLimit.toString(16)
    }

    this.executionContext.vm().stateManager.getAccount(Address.fromString(from)).then((res) => {
      // See https://github.com/ethereumjs/ethereumjs-tx/blob/master/docs/classes/transaction.md#constructor
      // for initialization fields and their types
      value = value ? parseInt(value) : 0
      const tx = Transaction.fromTxData({
        nonce: new BN(res.nonce),
        gasPrice: '0x1',
        gasLimit: gasLimit,
        to: to,
        value: value,
        data: Buffer.from(data.slice(2), 'hex')
      }, { common: this.commonContext }).sign(account.privateKey)

      const coinbases = ['0x0e9281e9c6a0808672eaba6bd1220e144c9bb07a', '0x8945a1288dc78a6d8952a92c77aee6730b414778', '0x94d76e24f818426ae84aa404140e8d5f60e10e7e']
      const difficulties = [new BN('69762765929000', 10), new BN('70762765929000', 10), new BN('71762765929000', 10)]

      var block = Block.fromBlockData({
        header: {
          timestamp: timestamp || (new Date().getTime() / 1000 | 0),
          number: self.blockNumber,
          coinbase: coinbases[self.blockNumber % coinbases.length],
          difficulty: difficulties[self.blockNumber % difficulties.length],
          gasLimit: new BN(gasLimit.replace('0x', ''), 16).imuln(2)
        },
        transactions: [tx]
      }, { common: this.commonContext })

      if (!useCall) {
        ++self.blockNumber
        this.runBlockInVm(tx, block, callback)
      } else {
        this.executionContext.vm().stateManager.checkpoint().then(() => {
          this.runBlockInVm(tx, block, (err, result) => {
            this.executionContext.vm().stateManager.revert().then(() => {
              callback(err, result)
            })
          })
        })
      }
    }).catch((e) => {
      callback(e)
    })
  }

  runBlockInVm (tx, block, callback) {
    this.executionContext.vm().runBlock({ block: block, generate: true, skipBlockValidation: true, skipBalance: false }).then((results) => {
      const result = results.results[0]
      if (result) {
        const status = result.execResult.exceptionError ? 0 : 1
        result.status = `0x${status}`
      }
      this.executionContext.addBlock(block)
      this.executionContext.trackTx('0x' + tx.hash().toString('hex'), block)
      callback(null, {
        result: result,
        transactionHash: bufferToHex(Buffer.from(tx.hash()))
      })
    }).catch((err) => {
      callback(err)
    })
  }

  runInNode (from, to, data, value, gasLimit, useCall, confirmCb, gasEstimationForceSend, promptCb, callback) {
    const tx = { from: from, to: to, data: data, value: value }

    if (useCall) {
      tx['gas'] = gasLimit
      return this.executionContext.web3().eth.call(tx, function (error, result) {
        callback(error, {
          result: result,
          transactionHash: result ? result.transactionHash : null
        })
      })
    }
    this.executionContext.web3().eth.estimateGas(tx, (err, gasEstimation) => {
      if (err && err.message.indexOf('Invalid JSON RPC response') !== -1) {
        // // @todo(#378) this should be removed when https://github.com/WalletConnect/walletconnect-monorepo/issues/334 is fixed
        err = 'Gas estimation failed because of an unknown internal error. This may indicated that the transaction will fail.'
      }
      gasEstimationForceSend(err, () => {
        // callback is called whenever no error
        tx['gas'] = !gasEstimation ? gasLimit : gasEstimation

        if (this._api.config.getUnpersistedProperty('doNotShowTransactionConfirmationAgain')) {
          return this._executeTx(tx, null, this._api, promptCb, callback)
        }

        this._api.detectNetwork((err, network) => {
          if (err) {
            console.log(err)
            return
          }

          confirmCb(network, tx, tx['gas'], (gasPrice) => {
            return this._executeTx(tx, gasPrice, this._api, promptCb, callback)
          }, (error) => {
            callback(error)
          })
        })
      }, () => {
        const blockGasLimit = this.executionContext.currentblockGasLimit()
        // NOTE: estimateGas very likely will return a large limit if execution of the code failed
        //       we want to be able to run the code in order to debug and find the cause for the failure
        if (err) return callback(err)

        let warnEstimation = ' An important gas estimation might also be the sign of a problem in the contract code. Please check loops and be sure you did not sent value to a non payable function (that\'s also the reason of strong gas estimation). '
        warnEstimation += ' ' + err

        if (gasEstimation > gasLimit) {
          return callback('Gas required exceeds limit: ' + gasLimit + '. ' + warnEstimation)
        }
        if (gasEstimation > blockGasLimit) {
          return callback('Gas required exceeds block gas limit: ' + gasLimit + '. ' + warnEstimation)
        }
      })
    })
  }
}

async function tryTillReceiptAvailable (txhash, executionContext) {
  return new Promise((resolve, reject) => {
    executionContext.web3().eth.getTransactionReceipt(txhash, async (err, receipt) => {
      if (err || !receipt) {
        // Try again with a bit of delay if error or if result still null
        await pause()
        return resolve(await tryTillReceiptAvailable(txhash, executionContext))
      }
      return resolve(receipt)
    })
  })
}

async function tryTillTxAvailable (txhash, executionContext) {
  return new Promise((resolve, reject) => {
    executionContext.web3().eth.getTransaction(txhash, async (err, tx) => {
      if (err || !tx) {
        // Try again with a bit of delay if error or if result still null
        await pause()
        return resolve(await tryTillTxAvailable(txhash, executionContext))
      }
      return resolve(tx)
    })
  })
}

async function pause () { return new Promise((resolve, reject) => { setTimeout(resolve, 500) }) }

function run (self, tx, stamp, confirmationCb, gasEstimationForceSend = null, promptCb = null, callback = null) {
  if (!self.runAsync && Object.keys(self.pendingTxs).length) {
    return self.queusTxs.push({ tx, stamp, callback })
  }
  self.pendingTxs[stamp] = tx
  self.execute(tx, confirmationCb, gasEstimationForceSend, promptCb, function (error, result) {
    delete self.pendingTxs[stamp]
    if (callback && typeof callback === 'function') callback(error, result)
    if (self.queusTxs.length) {
      const next = self.queusTxs.pop()
      run(self, next.tx, next.stamp, next.callback)
    }
  })
}