import { ProviderSource } from '../types'

export const MULTICALL_ADDRESS_MAINNET = "0xeefba1e63905ef1d7acba5a8513c70307c1ce441"
export const MULTICALL_ADDRESS_KOVAN = "0x2cc8688c5f75e365aaeeb4ea8d6a480405a48d2a"
export const MULTICALL_ADDRESS_RINKEBY = "0x42ad527de7d4e9d9d011ac45b31d8551f8fe9821"
export const MULTICALL_ADDRESS_GOERLI = "0x77dca2c955b15e9de4dbbcf1246b4b85b651e50e"
export const AGGREGATE_SELECTOR = '0x252dba42';

export class MulticallExecutor {

  constructor(
    private readonly providerSource: ProviderSource
  ) {}

  async execute(data: string) {
    const address = await this.multicallAddressOrThrow()

    const callData = AGGREGATE_SELECTOR + data.substr(2)

    const tx = {
      to: address,
      data: callData
    }
    const provider = await this.providerSource()

    const result = await provider.call(tx)

    return result
  }

  async multicallAddressOrThrow() {
    const provider = await this.providerSource()
    const network = await provider.getNetwork()
    const address = this.multicallAddress(network.chainId)
    if (address === null) {
      const msg = `multicall is not available on the network ${network.chainId}`
      console.error(msg)
      throw new Error(msg)
    }
    return address
  }

  async networkSupportsMulticall() {
    const provider = await this.providerSource()
    const network = await provider.getNetwork()
    const address = this.multicallAddress(network.chainId)
    return address !== null
  }

  multicallAddress(chainId: number) {
    switch (chainId) {
      case 1:
        return MULTICALL_ADDRESS_MAINNET
      case 42:
        return MULTICALL_ADDRESS_KOVAN
      case 4:
        return MULTICALL_ADDRESS_RINKEBY
      case 5:
        return MULTICALL_ADDRESS_GOERLI
      default:
        return null
    }
  }
}