KeyAuthorization.ts

import type * as Address from '../core/Address.js'
import type * as Errors from '../core/Errors.js'
import * as Hash from '../core/Hash.js'
import * as Hex from '../core/Hex.js'
import type { Compute } from '../core/internal/types.js'
import * as Rlp from '../core/Rlp.js'
import * as SignatureEnvelope from './SignatureEnvelope.js'
import * as TempoAddress from './TempoAddress.js'

/**
 * Key authorization for provisioning access keys.
 *
 * Access keys allow a root key (e.g., a passkey) to delegate transaction signing to secondary
 * keys with customizable permissions including expiry timestamps and per-TIP-20 token spending
 * limits. This enables a user to sign transactions without repeated passkey prompts.
 *
 * The root key signs a `KeyAuthorization` to grant an access key permission to sign transactions
 * on its behalf. The authorization is attached to a transaction (which can be signed by the access
 * key itself), and the protocol validates the authorization before storing the key in the
 * AccountKeychain precompile.
 *
 * Key authorization fields:
 * - `address`: Address derived from the access key's public key (the "key ID")
 * - `chainId`: Chain ID for replay protection (0 = valid on any chain)
 * - `expiry`: Unix timestamp when the key expires (undefined = never expires)
 * - `limits`: Per-TIP-20 token spending limits (only applies to `transfer()` and `approve()` calls)
 * - `type`: Key type (`secp256k1`, `p256`, or `webAuthn`)
 *
 * [Access Keys Specification](https://docs.tempo.xyz/protocol/transactions/spec-tempo-transaction#access-keys)
 */
export type KeyAuthorization<
  signed extends boolean = boolean,
  bigintType = bigint,
  numberType = number,
> = {
  /** Address derived from the public key of the key type. */
  address: Address.Address
  /** Chain ID for replay protection. */
  chainId: bigintType
  /** Unix timestamp when key expires (0 = never expires). */
  expiry?: numberType | null | undefined
  /** TIP20 spending limits for this key. */
  limits?: readonly TokenLimit<bigintType>[] | undefined
  /** Key type. (secp256k1, P256, WebAuthn). */
  type: SignatureEnvelope.Type
} & (signed extends true
  ? { signature: SignatureEnvelope.SignatureEnvelope<bigintType, numberType> }
  : {
      signature?:
        | SignatureEnvelope.SignatureEnvelope<bigintType, numberType>
        | undefined
    })

/** RPC representation of an {@link ox#KeyAuthorization.KeyAuthorization}. */
export type Rpc = Omit<
  KeyAuthorization<false, Hex.Hex, Hex.Hex>,
  'address' | 'signature' | 'type'
> & {
  keyId: Address.Address
  keyType: SignatureEnvelope.Type
  signature: SignatureEnvelope.SignatureEnvelopeRpc
}

/** Signed representation of a Key Authorization. */
export type Signed<bigintType = bigint, numberType = number> = KeyAuthorization<
  true,
  bigintType,
  numberType
>

type BaseTuple = readonly [
  chainId: Hex.Hex,
  keyType: Hex.Hex,
  keyId: Address.Address,
]

/** Tuple representation of a Key Authorization. */
export type Tuple<signed extends boolean = boolean> = signed extends true
  ? readonly [
      authorization:
        | BaseTuple
        | readonly [...BaseTuple, expiry: Hex.Hex]
        | readonly [
            ...BaseTuple,
            expiry: Hex.Hex,
            limits: readonly [token: Address.Address, limit: Hex.Hex][],
          ],
      signature: Hex.Hex,
    ]
  : readonly [
      authorization:
        | BaseTuple
        | readonly [...BaseTuple, expiry: Hex.Hex]
        | readonly [
            ...BaseTuple,
            expiry: Hex.Hex,
            limits: readonly [token: Address.Address, limit: Hex.Hex][],
          ],
    ]

/**
 * Token spending limit for access keys.
 *
 * Defines a per-TIP-20 token spending limit for an access key. Limits deplete as tokens
 * are spent and can be updated by the root key via `updateSpendingLimit()`.
 *
 * [Access Keys Specification](https://docs.tempo.xyz/protocol/transactions/spec-tempo-transaction#access-keys)
 */
export type TokenLimit<bigintType = bigint> = {
  /** Address of the TIP-20 token. */
  token: Address.Address
  /** Maximum spending amount for this token (enforced over the key's lifetime). */
  limit: bigintType
}

/**
 * Converts a Key Authorization object into a typed {@link ox#KeyAuthorization.KeyAuthorization}.
 *
 * Use this to create an unsigned key authorization, then sign it with the root key using
 * {@link ox#KeyAuthorization.(getSignPayload:function)} and attach the signature. The signed authorization
 * can be included in a {@link ox#TxEnvelopeTempo.TxEnvelopeTempo} via the
 * `keyAuthorization` field to provision the access key on-chain.
 *
 * [Access Keys Specification](https://docs.tempo.xyz/protocol/transactions/spec-tempo-transaction#access-keys)
 *
 * @example
 * ### Secp256k1 Key
 *
 * Standard Ethereum ECDSA key using the secp256k1 curve.
 *
 * ```ts twoslash
 * import { Address, Secp256k1, Value } from 'ox'
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const privateKey = Secp256k1.randomPrivateKey()
 * const address = Address.fromPublicKey(Secp256k1.getPublicKey({ privateKey }))
 *
 * const authorization = KeyAuthorization.from({
 *   address,
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6),
 *   }],
 * })
 * ```
 *
 * @example
 * ### WebCryptoP256 Key
 *
 * ```ts twoslash
 * import { Address, WebCryptoP256, Value } from 'ox'
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const keyPair = await WebCryptoP256.createKeyPair()
 * const address = Address.fromPublicKey(keyPair.publicKey)
 *
 * const authorization = KeyAuthorization.from({
 *   address,
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'p256',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6),
 *   }],
 * })
 * ```
 *
 * @example
 * ### Attaching Signatures (Secp256k1)
 *
 * Attach a signature to a Key Authorization using a Secp256k1 private key to
 * authorize another Secp256k1 key on the account.
 *
 * ```ts twoslash
 * import { Address, Secp256k1, Value } from 'ox'
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const privateKey = '0x...'
 * const address = Address.fromPublicKey(Secp256k1.getPublicKey({ privateKey }))
 *
 * const authorization = KeyAuthorization.from({
 *   address,
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6),
 *   }],
 * })
 *
 * const rootPrivateKey = '0x...'
 * const signature = Secp256k1.sign({
 *   payload: KeyAuthorization.getSignPayload(authorization),
 *   privateKey: rootPrivateKey,
 * })
 *
 * const authorization_signed = KeyAuthorization.from(authorization, { signature })
 * ```
 *
 * @example
 * ### Attaching Signatures (WebAuthn)
 *
 * Attach a signature to a Key Authorization using a WebAuthn credential to
 * authorize a new WebCryptoP256 key on the account.
 *
 * ```ts twoslash
 * // @noErrors
 * import { Address, Value, WebCryptoP256, WebAuthnP256 } from 'ox'
 * import { KeyAuthorization, SignatureEnvelope } from 'ox/tempo'
 *
 * const keyPair = await WebCryptoP256.createKeyPair()
 * const address = Address.fromPublicKey(keyPair.publicKey)
 *
 * const authorization = KeyAuthorization.from({
 *   address,
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'p256',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6),
 *   }],
 * })
 *
 * const credential = await WebAuthnP256.createCredential({ name: 'Example' })
 *
 * const { metadata, signature } = await WebAuthnP256.sign({
 *   challenge: KeyAuthorization.getSignPayload(authorization),
 *   credentialId: credential.id,
 * })
 *
 * const signatureEnvelope = SignatureEnvelope.from({ // [!code focus]
 *   signature, // [!code focus]
 *   publicKey: credential.publicKey, // [!code focus]
 *   metadata, // [!code focus]
 * })
 * const authorization_signed = KeyAuthorization.from(
 *   authorization,
 *   { signature: signatureEnvelope }, // [!code focus]
 * )
 * ```
 *
 * @param authorization - A Key Authorization tuple in object format.
 * @param options - Key Authorization options.
 * @returns The {@link ox#KeyAuthorization.KeyAuthorization}.
 */
export function from<
  const authorization extends KeyAuthorization | Rpc,
  const signature extends SignatureEnvelope.from.Value | undefined = undefined,
>(
  authorization:
    | authorization
    | KeyAuthorization
    | (Omit<KeyAuthorization, 'address' | 'limits'> & {
        address: TempoAddress.Address
        limits?:
          | readonly { token: TempoAddress.Address; limit: bigint }[]
          | undefined
      }),
  options: from.Options<signature> = {},
): from.ReturnType<authorization, signature> {
  if ('keyId' in authorization)
    return fromRpc(authorization as Rpc) as never
  const auth = authorization as KeyAuthorization & {
    limits?: readonly { token: TempoAddress.Address; limit: bigint }[]
  }
  const resolved = {
    ...auth,
    address: TempoAddress.resolve(auth.address as TempoAddress.Address),
    ...(auth.limits
      ? {
          limits: auth.limits.map((l) => ({
            ...l,
            token: TempoAddress.resolve(l.token as TempoAddress.Address),
          })),
        }
      : {}),
  }
  if (options.signature)
    return {
      ...resolved,
      signature: SignatureEnvelope.from(options.signature),
    } as never
  return resolved as never
}

export declare namespace from {
  type Options<
    signature extends SignatureEnvelope.from.Value | undefined =
      | SignatureEnvelope.from.Value
      | undefined,
  > = {
    /** The {@link ox#SignatureEnvelope.SignatureEnvelope} to attach to the Key Authorization. */
    signature?: signature | SignatureEnvelope.SignatureEnvelope | undefined
  }

  type ReturnType<
    authorization extends KeyAuthorization | Rpc = KeyAuthorization,
    signature extends SignatureEnvelope.from.Value | undefined =
      | SignatureEnvelope.from.Value
      | undefined,
  > = Compute<
    authorization extends Rpc
      ? Signed
      : authorization &
          (signature extends SignatureEnvelope.from.Value
            ? { signature: SignatureEnvelope.from.ReturnValue<signature> }
            : {})
  >

  type ErrorType = Errors.GlobalErrorType
}

/**
 * Converts an {@link ox#AuthorizationTempo.Rpc} to an {@link ox#AuthorizationTempo.AuthorizationTempo}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const keyAuthorization = KeyAuthorization.fromRpc({
 *   expiry: '0x174876e800',
 *   keyId: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   keyType: 'secp256k1',
 *   limits: [{ token: '0x20c0000000000000000000000000000000000001', limit: '0xf4240' }],
 *   signature: {
 *     type: 'secp256k1',
 *     r: '0x635dc2033e60185bb36709c29c75d64ea51dfbd91c32ef4be198e4ceb169fb4d',
 *     s: '0x50c2667ac4c771072746acfdcf1f1483336dcca8bd2df47cd83175dbe60f0540',
 *     yParity: '0x0'
 *   },
 * })
 * ```
 *
 * @param authorization - The RPC-formatted Key Authorization.
 * @returns A signed {@link ox#AuthorizationTempo.AuthorizationTempo}.
 */
export function fromRpc(authorization: Rpc): Signed {
  const { chainId, keyId, expiry = 0, limits, keyType } = authorization
  const signature = SignatureEnvelope.fromRpc(authorization.signature)
  return {
    address: keyId,
    chainId: chainId === '0x' ? 0n : Hex.toBigInt(chainId),
    expiry: Number(expiry),
    limits: limits?.map((limit) => ({
      token: limit.token,
      limit: BigInt(limit.limit),
    })),
    signature,
    type: keyType,
  }
}

export declare namespace fromRpc {
  type ErrorType = Errors.GlobalErrorType
}

/**
 * Converts an {@link ox#KeyAuthorization.Tuple} to an {@link ox#KeyAuthorization.KeyAuthorization}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const authorization = KeyAuthorization.fromTuple([
 *   [
 *     '0x',
 *     '0x00',
 *     '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *     '0x174876e800',
 *     [['0x20c0000000000000000000000000000000000001', '0xf4240']],
 *   ],
 *   '0x01a068a020a209d3d56c46f38cc50a33f704f4a9a10a59377f8dd762ac66910e9b907e865ad05c4035ab5792787d4a0297a43617ae897930a6fe4d822b8faea52064',
 * ])
 * ```
 *
 * @example
 * Unsigned Key Authorization tuple (no signature):
 *
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const authorization = KeyAuthorization.fromTuple([
 *   [
 *     '0x',
 *     '0x00',
 *     '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *     '0x174876e800',
 *     [['0x20c0000000000000000000000000000000000001', '0xf4240']],
 *   ],
 * ])
 * ```
 *
 * @param tuple - The Key Authorization tuple.
 * @returns The {@link ox#KeyAuthorization.KeyAuthorization}.
 */
export function fromTuple<const tuple extends Tuple>(
  tuple: tuple,
): fromTuple.ReturnType<tuple> {
  const [authorization, signatureSerialized] = tuple
  const [chainId, keyType_hex, keyId, expiry, limits] = authorization
  const keyType = (() => {
    switch (keyType_hex) {
      case '0x':
      case '0x00':
        return 'secp256k1'
      case '0x01':
        return 'p256'
      case '0x02':
        return 'webAuthn'
      default:
        throw new Error(`Invalid key type: ${keyType_hex}`)
    }
  })()
  const args: KeyAuthorization = {
    address: keyId,
    expiry: typeof expiry !== 'undefined' ? hexToNumber(expiry) : undefined,
    type: keyType,
    chainId: chainId === '0x' ? 0n : Hex.toBigInt(chainId),
    ...(typeof expiry !== 'undefined' ? { expiry: hexToNumber(expiry) } : {}),
    ...(typeof limits !== 'undefined'
      ? {
          limits: limits.map(([token, limit]) => ({
            token,
            limit: hexToBigint(limit),
          })),
        }
      : {}),
  }
  if (signatureSerialized)
    args.signature = SignatureEnvelope.deserialize(signatureSerialized)
  return from(args) as never
}

export declare namespace fromTuple {
  type ReturnType<authorization extends Tuple = Tuple> = Compute<
    KeyAuthorization<authorization extends Tuple<true> ? true : false>
  >

  type ErrorType = Errors.GlobalErrorType
}

/**
 * Computes the sign payload for an {@link ox#KeyAuthorization.KeyAuthorization}.
 *
 * The root key must sign this payload to authorize the access key. The resulting signature
 * is attached to the key authorization via {@link ox#KeyAuthorization.(from:function)} with the
 * `signature` option.
 *
 * [Access Keys Specification](https://docs.tempo.xyz/protocol/transactions/spec-tempo-transaction#access-keys)
 *
 * @example
 * ```ts twoslash
 * import { Address, Secp256k1, Value } from 'ox'
 * import { KeyAuthorization } from 'ox/tempo'
 *
 * const privateKey = '0x...'
 * const address = Address.fromPublicKey(Secp256k1.getPublicKey({ privateKey }))
 *
 * const authorization = KeyAuthorization.from({
 *   address,
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6),
 *   }],
 * })
 *
 * const payload = KeyAuthorization.getSignPayload(authorization) // [!code focus]
 * ```
 *
 * @param authorization - The {@link ox#KeyAuthorization.KeyAuthorization}.
 * @returns The sign payload.
 */
export function getSignPayload(authorization: KeyAuthorization): Hex.Hex {
  return hash(authorization)
}

export declare namespace getSignPayload {
  type ErrorType = hash.ErrorType | Errors.GlobalErrorType
}

/**
 * Deserializes an RLP-encoded {@link ox#KeyAuthorization.KeyAuthorization}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 * import { Value } from 'ox'
 *
 * const authorization = KeyAuthorization.from({
 *   address: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6)
 *   }],
 * })
 *
 * const serialized = KeyAuthorization.serialize(authorization)
 * const deserialized = KeyAuthorization.deserialize(serialized) // [!code focus]
 * ```
 *
 * @param serialized - The RLP-encoded Key Authorization.
 * @returns The {@link ox#KeyAuthorization.KeyAuthorization}.
 */
export function deserialize(serialized: Hex.Hex): KeyAuthorization {
  const tuple = Rlp.toHex(serialized) as unknown as Tuple
  return fromTuple(tuple)
}

export declare namespace deserialize {
  type ErrorType =
    | Rlp.toHex.ErrorType
    | fromTuple.ErrorType
    | Errors.GlobalErrorType
}

/**
 * Computes the hash for an {@link ox#KeyAuthorization.KeyAuthorization}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 * import { Value } from 'ox'
 *
 * const authorization = KeyAuthorization.from({
 *   address: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6)
 *   }],
 * })
 *
 * const hash = KeyAuthorization.hash(authorization) // [!code focus]
 * ```
 *
 * @param authorization - The {@link ox#KeyAuthorization.KeyAuthorization}.
 * @returns The hash.
 */
export function hash(authorization: KeyAuthorization): Hex.Hex {
  const [authorizationTuple] = toTuple(authorization)
  const serialized = Rlp.fromHex(authorizationTuple)
  return Hash.keccak256(serialized)
}

export declare namespace hash {
  type ErrorType =
    | toTuple.ErrorType
    | Hash.keccak256.ErrorType
    | Hex.concat.ErrorType
    | Rlp.fromHex.ErrorType
    | Errors.GlobalErrorType
}

/**
 * Serializes a {@link ox#KeyAuthorization.KeyAuthorization} to RLP-encoded hex.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 * import { Value } from 'ox'
 *
 * const authorization = KeyAuthorization.from({
 *   address: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6)
 *   }],
 * })
 *
 * const serialized = KeyAuthorization.serialize(authorization) // [!code focus]
 * ```
 *
 * @param authorization - The {@link ox#KeyAuthorization.KeyAuthorization}.
 * @returns The RLP-encoded Key Authorization.
 */
export function serialize(authorization: KeyAuthorization): Hex.Hex {
  const tuple = toTuple(authorization)
  return Rlp.fromHex(tuple as any)
}

export declare namespace serialize {
  type ErrorType =
    | toTuple.ErrorType
    | Rlp.fromHex.ErrorType
    | Errors.GlobalErrorType
}

/**
 * Converts an {@link ox#KeyAuthorization.KeyAuthorization} to an {@link ox#KeyAuthorization.Rpc}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 * import { Value } from 'ox'
 *
 * const authorization = KeyAuthorization.toRpc({
 *   address: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6)
 *   }],
 *   signature: {
 *     type: 'secp256k1',
 *     signature: {
 *       r: 44944627813007772897391531230081695102703289123332187696115181104739239197517n,
 *       s: 36528503505192438307355164441104001310566505351980369085208178712678799181120n,
 *       yParity: 0,
 *     },
 *   },
 * })
 * ```
 *
 * @param authorization - A Key Authorization.
 * @returns An RPC-formatted Key Authorization.
 */
export function toRpc(authorization: Signed): Rpc {
  const { address, chainId, expiry, limits, type, signature } = authorization

  return {
    chainId: chainId === 0n ? '0x' : Hex.fromNumber(chainId),
    expiry: typeof expiry === 'number' ? Hex.fromNumber(expiry) : null,
    limits: limits?.map(({ token, limit }) => ({
      token,
      limit: Hex.fromNumber(limit),
    })),
    keyId: address,
    signature: SignatureEnvelope.toRpc(signature),
    keyType: type,
  }
}

export declare namespace toRpc {
  type ErrorType = Errors.GlobalErrorType
}

/**
 * Converts an {@link ox#KeyAuthorization.KeyAuthorization} to an {@link ox#KeyAuthorization.Tuple}.
 *
 * @example
 * ```ts twoslash
 * import { KeyAuthorization } from 'ox/tempo'
 * import { Value } from 'ox'
 *
 * const authorization = KeyAuthorization.from({
 *   address: '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 *   chainId: 4217n,
 *   expiry: 1234567890,
 *   type: 'secp256k1',
 *   limits: [{
 *     token: '0x20c0000000000000000000000000000000000001',
 *     limit: Value.from('10', 6)
 *   }],
 * })
 *
 * const tuple = KeyAuthorization.toTuple(authorization) // [!code focus]
 * // @log: [
 * // @log:   '0x174876e800',
 * // @log:   [['0x20c0000000000000000000000000000000000001', '0xf4240']],
 * // @log:   '0xbe95c3f554e9fc85ec51be69a3d807a0d55bcf2c',
 * // @log:   'secp256k1',
 * // @log: ]
 * ```
 *
 * @param authorization - The {@link ox#KeyAuthorization.KeyAuthorization}.
 * @returns A Tempo Key Authorization tuple.
 */
export function toTuple<const authorization extends KeyAuthorization>(
  authorization: authorization,
): toTuple.ReturnType<authorization> {
  const { address, chainId, expiry, limits } = authorization
  const signature = authorization.signature
    ? SignatureEnvelope.serialize(authorization.signature)
    : undefined
  const type = (() => {
    switch (authorization.type) {
      case 'secp256k1':
        return '0x'
      case 'p256':
        return '0x01'
      case 'webAuthn':
        return '0x02'
      default:
        throw new Error(`Invalid key type: ${authorization.type}`)
    }
  })()
  const limitsValue = limits?.map((limit) => [
    limit.token,
    bigintToHex(limit.limit),
  ])
  const authorizationTuple = [
    bigintToHex(chainId),
    type,
    address,
    // expiry is required in the tuple when limits are present
    typeof expiry === 'number' || limitsValue
      ? numberToHex(expiry ?? 0)
      : undefined,
    limitsValue,
  ].filter(Boolean)
  return [authorizationTuple, ...(signature ? [signature] : [])] as never
}

export declare namespace toTuple {
  type ReturnType<authorization extends KeyAuthorization = KeyAuthorization> =
    Compute<Tuple<authorization extends KeyAuthorization<true> ? true : false>>

  type ErrorType = Errors.GlobalErrorType
}

function bigintToHex(value: bigint): Hex.Hex {
  return value === 0n ? '0x' : Hex.fromNumber(value)
}

function numberToHex(value: number): Hex.Hex {
  return value === 0 ? '0x' : Hex.fromNumber(value)
}

function hexToBigint(hex: Hex.Hex): bigint {
  return hex === '0x' ? 0n : BigInt(hex)
}

function hexToNumber(hex: Hex.Hex): number {
  return hex === '0x' ? 0 : Hex.toNumber(hex)
}