import { SubstateT, SubStateType } from './_types'
import { Result } from 'neverthrow'
import { Tokens } from './tokens'
import { PreparedStake } from './preparedStake'
import { PreparedUnstake } from './preparedUnstake'
import { StakeOwnership } from './stakeOwnership'
import { ValidatorAllowDelegationFlag } from './validatorAllowDelegationFlag'
import { BufferReaderT } from '@util'
import { ValidatorOwnerCopy } from './validatorOwnerCopy'

const LENGTH_BYTES = 2
const TYPE_BYTES = 1

const parseFromBufferReader = (
  bufferReader: BufferReaderT,
): Result<SubstateT, Error> =>
  bufferReader
    .readNextBuffer(LENGTH_BYTES + TYPE_BYTES)
    .map(b => {
      const lengthData = Buffer.from(b.slice(0, LENGTH_BYTES))
      return [b.readUInt8(LENGTH_BYTES), lengthData]
    })
    .map(([type, lengthData]) => [type, lengthData] as [SubStateType, Buffer])
    .andThen(([substateType, lengthData]): Result<SubstateT, Error> => {
      switch (substateType) {
        case SubStateType.TOKENS:
          return Tokens.fromBufferReader(bufferReader, lengthData)
        case SubStateType.PREPARED_STAKE:
          return PreparedStake.fromBufferReader(bufferReader, lengthData)
        case SubStateType.PREPARED_UNSTAKE:
          return PreparedUnstake.fromBufferReader(bufferReader, lengthData)
        case SubStateType.STAKE_OWNERSHIP:
          return StakeOwnership.fromBufferReader(bufferReader, lengthData)
        case SubStateType.VALIDATOR_ALLOW_DELEGATION_FLAG:
          return ValidatorAllowDelegationFlag.fromBufferReader(
            bufferReader,
            lengthData,
          )
        case SubStateType.VALIDATOR_OWNER_COPY:
          return ValidatorOwnerCopy.fromBufferReader(bufferReader, lengthData)
        default:
          throw new Error(
            `Substate ${substateType} of type: ${SubStateType[substateType]} not implemented.`,
          )
      }
    })

export const Substate = {
  parseFromBufferReader,
}