import { BigNumber, ethers } from "ethers"
import { arrayify } from "ethers/lib/utils"

export enum RelayerPayloadId {
  Delivery = 1,
  // DeliveryStatus = 3,
}

export enum DeliveryStatus {
  WaitingForVAA = "Waiting for VAA",
  PendingDelivery = "Pending Delivery",
  DeliverySuccess = "Delivery Success",
  ReceiverFailure = "Receiver Failure",
  InvalidRedelivery = "Invalid Redelivery",
  ForwardRequestSuccess = "Forward Request Success",
  ForwardRequestFailure = "Forward Request Failure",
  ThisShouldNeverHappen = "This should never happen. Contact Support.",
  DeliveryDidntHappenWithinRange = "Delivery didn't happen within given block range",
}

export interface DeliveryInstructionsContainer {
  payloadId: number // 1
  messages: MessageInfo[]
  instructions: DeliveryInstruction[]
}

export interface MessageInfo {
  payloadType: MessageInfoType
  emitterAddress?: Buffer
  sequence?: BigNumber
  vaaHash?: Buffer
}

export interface DeliveryInstruction {
  targetChain: number
  targetAddress: Buffer
  refundAddress: Buffer
  maximumRefundTarget: BigNumber
  receiverValueTarget: BigNumber
  executionParameters: ExecutionParameters
}

export interface ExecutionParameters {
  version: number
  gasLimit: number
  providerDeliveryAddress: Buffer
}

export enum MessageInfoType {
  EMITTER_SEQUENCE = 0,
  VAAHASH = 1,
}

export function parseWormholeRelayerPayloadType(
  stringPayload: string | Buffer | Uint8Array
): RelayerPayloadId {
  const payload =
    typeof stringPayload === "string" ? arrayify(stringPayload) : stringPayload
  if (payload[0] == 0 || payload[0] >= 3) {
    throw new Error("Unrecogned payload type " + payload[0])
  }
  return payload[0]
}

export function parseWormholeRelayerSend(bytes: Buffer): DeliveryInstructionsContainer {
  let idx = 0
  const payloadId = bytes.readUInt8(idx)
  if (payloadId !== RelayerPayloadId.Delivery) {
    throw new Error(
      `Expected Delivery payload type (${RelayerPayloadId.Delivery}), found: ${payloadId}`
    )
  }
  idx += 1

  const numMessages = bytes.readUInt8(idx)
  idx += 1

  let messages = [] as MessageInfo[]
  for (let i = 0; i < numMessages; ++i) {
    const res = parseMessageInfo(bytes, idx)
    idx = res[1]
    messages.push(res[0])
  }

  const numInstructions = bytes.readUInt8(idx)
  idx += 1

  let instructions = [] as DeliveryInstruction[]
  for (let i = 0; i < numInstructions; ++i) {
    const targetChain = bytes.readUInt16BE(idx)
    idx += 2
    const targetAddress = bytes.slice(idx, idx + 32)
    idx += 32
    const refundAddress = bytes.slice(idx, idx + 32)
    idx += 32
    const maximumRefundTarget = ethers.BigNumber.from(
      Uint8Array.prototype.subarray.call(bytes, idx, idx + 32)
    )
    idx += 32
    const receiverValueTarget = ethers.BigNumber.from(
      Uint8Array.prototype.subarray.call(bytes, idx, idx + 32)
    )
    idx += 32
    let res = parseWormholeRelayerExecutionParameters(bytes, idx)
    const executionParameters = res[0]
    idx = res[1]
    instructions.push(
      // dumb typechain format
      {
        targetChain,
        targetAddress,
        refundAddress,
        maximumRefundTarget,
        receiverValueTarget,
        executionParameters,
      }
    )
  }

  return {
    payloadId,
    messages,
    instructions,
  }
}

function parseMessageInfo(bytes: Buffer, idx: number): [MessageInfo, number] {
  const payloadId = bytes.readUint8(idx)
  idx += 1
  const payloadType = bytes.readUint8(idx) as MessageInfoType
  idx += 1
  if (payloadType == MessageInfoType.EMITTER_SEQUENCE) {
    const emitterAddress = bytes.slice(idx, idx + 32)
    idx += 32
    const sequence = ethers.BigNumber.from(
      Uint8Array.prototype.subarray.call(bytes, idx, idx + 8)
    )
    idx += 8
    return [
      {
        payloadType,
        emitterAddress,
        sequence,
      },
      idx,
    ]
  } else if (payloadType == MessageInfoType.VAAHASH) {
    const vaaHash = bytes.slice(idx, idx + 32)
    idx += 32
    return [
      {
        payloadType,
        vaaHash,
      },
      idx,
    ]
  } else {
    throw new Error("Unexpected MessageInfo payload type")
  }
}

function parseWormholeRelayerExecutionParameters(
  bytes: Buffer,
  idx: number
): [ExecutionParameters, number] {
  const version = bytes.readUInt8(idx)
  idx += 1
  const gasLimit = bytes.readUint32BE(idx)
  idx += 4
  const providerDeliveryAddress = bytes.slice(idx, idx + 32)
  idx += 32
  return [{ version, gasLimit, providerDeliveryAddress }, idx]
}

/*
 * Helpers
 */

export function dbg<T>(x: T, msg?: string): T {
  if (msg) {
    console.log("[DEBUG] " + msg)
  }
  console.log(x)
  return x
}