import { IAgentContext, IIdentifier, IKey, IKeyManager, IService } from '@veramo/core-types'
import { AbstractIdentifierProvider } from '@veramo/did-manager'
import { bytesToBase64url, bytesToMultibase, hexToBytes, stringToUtf8Bytes, importOrCreateKey, CreateIdentifierBaseOptions, ImportOrCreateKeyOptions } from '@veramo/utils'

import Debug from 'debug'

const debug = Debug('veramo:did-peer:identifier-provider')

type IContext = IAgentContext<IKeyManager>

const ServiceReplacements = {
  type: 't',
  DIDCommMessaging: 'dm',
  serviceEndpoint: 's',
  routingKeys: 'r',
  accept: 'a',
}

const encodeService = (service: IService): string => {
  let encoded = JSON.stringify(service)
  Object.values(ServiceReplacements).forEach((v: string, idx: number) => {
    encoded = encoded.replace(Object.keys(ServiceReplacements)[idx], v)
  })
  return bytesToBase64url(stringToUtf8Bytes(encoded))
}

type CreatePeerDidOptions = CreateIdentifierBaseOptions<'Ed25519'> & {
  num_algo: number
  // keyType?: keyof typeof keyCodecs // defaulting to Ed25519 keys only in this implementation
  
  /**
   * @deprecated use key.privateKeyHex instead
   */
  authPrivateKeyHex?: string

  /**
   * @deprecated use agreementKey.privateKeyHex instead
   */
  agreementPrivateKeyHex?: string

  service?: IService

  agreementKeyRef?: string;
  agreementKey?: ImportOrCreateKeyOptions<'X25519'>
}

/**
 * {@link @veramo/did-manager#DIDManager} identifier provider for `did:key` identifiers
 *
 * @beta This API may change without a BREAKING CHANGE notice.
 */
export class PeerDIDProvider extends AbstractIdentifierProvider {
  private defaultKms: string

  constructor(options: { defaultKms: string }) {
    super()
    this.defaultKms = options.defaultKms
  }

  async createIdentifier(
    { kms, options }: { kms?: string; options?: CreatePeerDidOptions },
    context: IContext,
  ): Promise<Omit<IIdentifier, 'provider'>> {
    options = options ?? { num_algo: 0 }
    if (options.service) {
      options.num_algo = 2
    }

    const authPrivateKeyHex = options?.key?.privateKeyHex || options?.authPrivateKeyHex
    const agreementPrivateKeyHex = options?.agreementKey?.privateKeyHex || options?.agreementPrivateKeyHex
    
    let key: IKey
    let agreementKey: IKey | undefined

    // Exit early so we don't create a key if we can't continue
    if (![0, 2].includes(options.num_algo)) {
      throw new Error(`not_supported: PeerDIDProvider num algo ${options.num_algo} not supported yet.`)
    }

    if (options.agreementKeyRef) {
      agreementKey = await context.agent.keyManagerGet({ kid: options.agreementKeyRef })
      if (agreementKey.type !== 'X25519') {
        throw new Error('not_supported: Key type must be X25519')
      }
    }

    if (options.keyRef) {
      key = await context.agent.keyManagerGet({ kid: options.keyRef })
      if (key.type !== 'Ed25519') {
        throw new Error('not_supported: Key type must be Ed25519')
      }
    } else {
      key = await importOrCreateKey({
        kms: kms || this.defaultKms,
        options: {
          ...(options?.key ?? {}),
          type: 'Ed25519',
          privateKeyHex: authPrivateKeyHex,
        }
      }, context)
    }

    switch (options.num_algo) {
      case 0: {
        const methodSpecificId = bytesToMultibase(hexToBytes(key.publicKeyHex), 'base58btc', 'ed25519-pub')
        const identifier: Omit<IIdentifier, 'provider'> = {
          did: 'did:peer:0' + methodSpecificId,
          controllerKeyId: key.kid,
          keys: [key],
          services: [],
        }
        debug('Created', identifier.did)
        return identifier
      }

      case 2: {
        if (!agreementKey) {
          agreementKey = await importOrCreateKey({
            kms: kms || this.defaultKms,
            options: {
              ...(options?.agreementKey ?? {}),
              type: 'X25519',
              privateKeyHex: agreementPrivateKeyHex,
            }
          }, context)
        }

        const authKeyText = bytesToMultibase(hexToBytes(key.publicKeyHex), 'base58btc', 'ed25519-pub')

        const agreementKeyText = bytesToMultibase(
          hexToBytes(agreementKey.publicKeyHex),
          'base58btc',
          'x25519-pub',
        )

        let serviceString = ''

        if (options.service) {
          serviceString = `.S${encodeService(options.service)}`
        }

        const identifier: Omit<IIdentifier, 'provider'> = {
          did: `did:peer:2.E${agreementKeyText}.V${authKeyText}${serviceString}`,
          controllerKeyId: key.kid,
          keys: [key, agreementKey],
          services: options.service ? [options.service] : [],
        }
        debug('Created', identifier.did)
        return identifier
      }

      default:
        throw new Error(`'not_supported: PeerDIDProvider num algo ${options.num_algo} not supported yet.'`)
    }
  }

  async updateIdentifier(
    args: { did: string; kms?: string | undefined; alias?: string | undefined; options?: any },
    context: IAgentContext<IKeyManager>,
  ): Promise<IIdentifier> {
    throw new Error('not_supported: PeerDIDProvider updateIdentifier not supported yet.')
  }

  async deleteIdentifier(identifier: IIdentifier, context: IContext): Promise<boolean> {
    for (const { kid } of identifier.keys) {
      await context.agent.keyManagerDelete({ kid })
    }
    return true
  }

  async addKey(
    { identifier, key, options }: { identifier: IIdentifier; key: IKey; options?: any },
    context: IContext,
  ): Promise<any> {
    throw Error('not_supported: PeerDIDProvider addKey not supported')
  }

  async addService(
    { identifier, service, options }: { identifier: IIdentifier; service: IService; options?: any },
    context: IContext,
  ): Promise<any> {
    throw Error('not_supported: PeerDIDProvider addService not supported')
  }

  async removeKey(
    args: { identifier: IIdentifier; kid: string; options?: any },
    context: IContext,
  ): Promise<any> {
    throw Error('not_supported: PeerDIDProvider removeKey not supported')
  }

  async removeService(
    args: { identifier: IIdentifier; id: string; options?: any },
    context: IContext,
  ): Promise<any> {
    throw Error('not_supported: PeerDIDProvider removeService not supported')
  }
}