import { Hasher, TypedArrayEncoder } from '@aries-framework/core'

const ATTRIB_TYPE = '100'
const GET_ATTR_TYPE = '104'

/// Generate the normalized form of a ledger transaction request for signing
export function serializeRequestForSignature(v: any): string {
  const type = v?.operation?.type

  return _serializeRequestForSignature(v, true, type != undefined ? `${type}` : undefined)
}

/**
 * Serialize an indy ledger request object for signing input. Based on the rust code. Indy SDK requires ledger requests to be signed using
 * a did, however in AFJ's the wallet only creates keys, and we create custom did records. This allows us to remove the legacy createDid and
 * publicDidSeed properties from the wallet, as we create the request payload ourselves.
 *
 * @see https://github.com/hyperledger/indy-shared-rs/blob/6af1e939586d1f16341dc03b62970cf28b32d118/indy-utils/src/txn_signature.rs#L10
 */
function _serializeRequestForSignature(v: any, isTopLevel: boolean, _type?: string): string {
  const vType = typeof v

  if (vType === 'boolean') return v ? 'True' : 'False'
  if (vType === 'number') return v.toString()
  if (vType === 'string') return v

  if (vType === 'object') {
    if (Array.isArray(v)) {
      return v.map((element) => _serializeRequestForSignature(element, false, _type)).join(',')
    }

    let result = ''
    let inMiddle = false

    for (const vKey of Object.keys(v).sort()) {
      // Skip signature field at top level as in python code
      if (isTopLevel && (vKey == 'signature' || vKey == 'fees' || vKey == 'signatures')) {
        continue
      }

      if (inMiddle) {
        result += '|'
      }

      let value = v[vKey]
      if ((_type == ATTRIB_TYPE || _type == GET_ATTR_TYPE) && (vKey == 'raw' || vKey == 'hash' || vKey == 'enc')) {
        // do it only for attribute related request
        if (typeof value !== 'string') throw new Error('Value must be a string for hash')
        const hash = Hasher.hash(TypedArrayEncoder.fromString(value), 'sha2-256')
        value = Buffer.from(hash).toString('hex')
      }

      result = `${result}${vKey}:${_serializeRequestForSignature(value, false, _type)}`
      inMiddle = true
    }

    return result
  }

  return ''
}