import {
  InvalidSerializedTransactionTypeError,
  type InvalidSerializedTransactionTypeErrorType,
} from '../../errors/transaction.js'
import type { ErrorType } from '../../errors/utils.js'
import type { Hex } from '../../index.js'
import type {
  TransactionSerialized,
  TransactionSerializedEIP1559,
  TransactionSerializedEIP2930,
  TransactionSerializedEIP4844,
  TransactionSerializedEIP7702,
  TransactionSerializedGeneric,
  TransactionSerializedLegacy,
  TransactionType,
} from '../../types/transaction.js'
import type { IsNarrowable, IsNever } from '../../types/utils.js'
import { type SliceHexErrorType, sliceHex } from '../data/slice.js'
import { type HexToNumberErrorType, hexToNumber } from '../encoding/fromHex.js'

export type GetSerializedTransactionType<
  serializedTransaction extends
    TransactionSerializedGeneric = TransactionSerialized,
  result =
    | (serializedTransaction extends TransactionSerializedEIP1559
        ? 'eip1559'
        : never)
    | (serializedTransaction extends TransactionSerializedEIP2930
        ? 'eip2930'
        : never)
    | (serializedTransaction extends TransactionSerializedEIP4844
        ? 'eip4844'
        : never)
    | (serializedTransaction extends TransactionSerializedEIP7702
        ? 'eip7702'
        : never)
    | (serializedTransaction extends TransactionSerializedLegacy
        ? 'legacy'
        : never),
> = IsNarrowable<serializedTransaction, Hex> extends true
  ? IsNever<result> extends false
    ? result
    : 'legacy'
  : TransactionType

export type GetSerializedTransactionTypeErrorType =
  | HexToNumberErrorType
  | InvalidSerializedTransactionTypeErrorType
  | SliceHexErrorType
  | ErrorType

export function getSerializedTransactionType<
  const serializedTransaction extends TransactionSerializedGeneric,
>(
  serializedTransaction: serializedTransaction,
): GetSerializedTransactionType<serializedTransaction> {
  const serializedType = sliceHex(serializedTransaction, 0, 1)

  if (serializedType === '0x04')
    return 'eip7702' as GetSerializedTransactionType<serializedTransaction>

  if (serializedType === '0x03')
    return 'eip4844' as GetSerializedTransactionType<serializedTransaction>

  if (serializedType === '0x02')
    return 'eip1559' as GetSerializedTransactionType<serializedTransaction>

  if (serializedType === '0x01')
    return 'eip2930' as GetSerializedTransactionType<serializedTransaction>

  if (serializedType !== '0x' && hexToNumber(serializedType) >= 0xc0)
    return 'legacy' as GetSerializedTransactionType<serializedTransaction>

  throw new InvalidSerializedTransactionTypeError({ serializedType })
}