import EventEmitter from 'events';
import log from 'loglevel';
import {
  EncryptionPublicKeyManager,
  EncryptionPublicKeyParamsMetamask,
} from '@metamask/message-manager';
import { KeyringController } from '@metamask/eth-keyring-controller';
import {
  AbstractMessageManager,
  AbstractMessage,
  MessageManagerState,
  AbstractMessageParams,
  AbstractMessageParamsMetamask,
  OriginalRequest,
} from '@metamask/message-manager/dist/AbstractMessageManager';
import {
  BaseControllerV2,
  RestrictedControllerMessenger,
} from '@metamask/base-controller';
import { Patch } from 'immer';
import {
  AcceptRequest,
  AddApprovalRequest,
  RejectRequest,
} from '@metamask/approval-controller';
import { MetaMetricsEventCategory } from '../../../shared/constants/metametrics';
import { KeyringType } from '../../../shared/constants/keyring';
import { ORIGIN_METAMASK } from '../../../shared/constants/app';

const controllerName = 'EncryptionPublicKeyController';
const methodNameGetEncryptionPublicKey = 'eth_getEncryptionPublicKey';

const stateMetadata = {
  unapprovedEncryptionPublicKeyMsgs: { persist: false, anonymous: false },
  unapprovedEncryptionPublicKeyMsgCount: { persist: false, anonymous: false },
};

const getDefaultState = () => ({
  unapprovedEncryptionPublicKeyMsgs: {},
  unapprovedEncryptionPublicKeyMsgCount: 0,
});

export type CoreMessage = AbstractMessage & {
  messageParams: AbstractMessageParams;
};

export type StateMessage = Required<
  Omit<AbstractMessage, 'securityProviderResponse'>
> & {
  msgParams: string;
};

export type EncryptionPublicKeyControllerState = {
  unapprovedEncryptionPublicKeyMsgs: Record<string, StateMessage>;
  unapprovedEncryptionPublicKeyMsgCount: number;
};

export type GetEncryptionPublicKeyState = {
  type: `${typeof controllerName}:getState`;
  handler: () => EncryptionPublicKeyControllerState;
};

export type EncryptionPublicKeyStateChange = {
  type: `${typeof controllerName}:stateChange`;
  payload: [EncryptionPublicKeyControllerState, Patch[]];
};

export type EncryptionPublicKeyControllerActions = GetEncryptionPublicKeyState;

export type EncryptionPublicKeyControllerEvents =
  EncryptionPublicKeyStateChange;

type AllowedActions = AddApprovalRequest | AcceptRequest | RejectRequest;

export type EncryptionPublicKeyControllerMessenger =
  RestrictedControllerMessenger<
    typeof controllerName,
    EncryptionPublicKeyControllerActions | AllowedActions,
    EncryptionPublicKeyControllerEvents,
    AllowedActions['type'],
    never
  >;

export type EncryptionPublicKeyControllerOptions = {
  messenger: EncryptionPublicKeyControllerMessenger;
  keyringController: KeyringController;
  getState: () => any;
  metricsEvent: (payload: any, options?: any) => void;
};

/**
 * Controller for requesting encryption public key requests requiring user approval.
 */
export default class EncryptionPublicKeyController extends BaseControllerV2<
  typeof controllerName,
  EncryptionPublicKeyControllerState,
  EncryptionPublicKeyControllerMessenger
> {
  hub: EventEmitter;

  private _keyringController: KeyringController;

  private _getState: () => any;

  private _encryptionPublicKeyManager: EncryptionPublicKeyManager;

  private _metricsEvent: (payload: any, options?: any) => void;

  /**
   * Construct a EncryptionPublicKey controller.
   *
   * @param options - The controller options.
   * @param options.messenger - The restricted controller messenger for the EncryptionPublicKey controller.
   * @param options.keyringController - An instance of a keyring controller used to extract the encryption public key.
   * @param options.getState - Callback to retrieve all user state.
   * @param options.metricsEvent - A function for emitting a metric event.
   */
  constructor({
    messenger,
    keyringController,
    getState,
    metricsEvent,
  }: EncryptionPublicKeyControllerOptions) {
    super({
      name: controllerName,
      metadata: stateMetadata,
      messenger,
      state: getDefaultState(),
    });

    this._keyringController = keyringController;
    this._getState = getState;
    this._metricsEvent = metricsEvent;

    this.hub = new EventEmitter();
    this._encryptionPublicKeyManager = new EncryptionPublicKeyManager(
      undefined,
      undefined,
      undefined,
      ['received'],
    );

    this._encryptionPublicKeyManager.hub.on('updateBadge', () => {
      this.hub.emit('updateBadge');
    });

    this._encryptionPublicKeyManager.hub.on(
      'unapprovedMessage',
      (msgParams: AbstractMessageParamsMetamask) => {
        this._requestApproval(msgParams, methodNameGetEncryptionPublicKey);
      },
    );

    this._subscribeToMessageState(
      this._encryptionPublicKeyManager,
      (state, newMessages, messageCount) => {
        state.unapprovedEncryptionPublicKeyMsgs = newMessages;
        state.unapprovedEncryptionPublicKeyMsgCount = messageCount;
      },
    );
  }

  /**
   * A getter for the number of 'unapproved' Messages in this.messages
   *
   * @returns The number of 'unapproved' Messages in this.messages
   */
  get unapprovedMsgCount(): number {
    return this._encryptionPublicKeyManager.getUnapprovedMessagesCount();
  }

  /**
   * Reset the controller state to the initial state.
   */
  resetState() {
    this.update(() => getDefaultState());
  }

  /**
   * Called when a Dapp uses the eth_getEncryptionPublicKey method, to request user approval.
   *
   * @param address - The address from the encryption public key will be extracted.
   * @param [req] - The original request, containing the origin.
   */
  async newRequestEncryptionPublicKey(
    address: string,
    req: OriginalRequest,
  ): Promise<string> {
    const keyring = await this._keyringController.getKeyringForAccount(address);

    switch (keyring.type) {
      case KeyringType.ledger: {
        return new Promise((_, reject) => {
          reject(
            new Error('Ledger does not support eth_getEncryptionPublicKey.'),
          );
        });
      }

      case KeyringType.trezor: {
        return new Promise((_, reject) => {
          reject(
            new Error('Trezor does not support eth_getEncryptionPublicKey.'),
          );
        });
      }

      case KeyringType.lattice: {
        return new Promise((_, reject) => {
          reject(
            new Error('Lattice does not support eth_getEncryptionPublicKey.'),
          );
        });
      }

      case KeyringType.qr: {
        return Promise.reject(
          new Error('QR hardware does not support eth_getEncryptionPublicKey.'),
        );
      }

      default: {
        return this._encryptionPublicKeyManager.addUnapprovedMessageAsync(
          { from: address },
          req,
        );
      }
    }
  }

  /**
   * Signifies a user's approval to receiving encryption public key in queue.
   *
   * @param msgParams - The params of the message to receive & return to the Dapp.
   * @returns A full state update.
   */
  async encryptionPublicKey(msgParams: EncryptionPublicKeyParamsMetamask) {
    log.info('MetaMaskController - encryptionPublicKey');
    const messageId = msgParams.metamaskId as string;
    // sets the status op the message to 'approved'
    // and removes the metamaskId for decryption
    try {
      const cleanMessageParams =
        await this._encryptionPublicKeyManager.approveMessage(msgParams);

      // EncryptionPublicKey message
      const publicKey = await this._keyringController.getEncryptionPublicKey(
        cleanMessageParams.from,
      );

      // tells the listener that the message has been processed
      // and can be returned to the dapp
      this._encryptionPublicKeyManager.setMessageStatusAndResult(
        messageId,
        publicKey,
        'received',
      );

      this._acceptApproval(messageId);

      return this._getState();
    } catch (error) {
      log.info(
        'MetaMaskController - eth_getEncryptionPublicKey failed.',
        error,
      );
      this._cancelAbstractMessage(this._encryptionPublicKeyManager, messageId);
      throw error;
    }
  }

  /**
   * Used to cancel a message submitted via eth_getEncryptionPublicKey.
   *
   * @param msgId - The id of the message to cancel.
   */
  cancelEncryptionPublicKey(msgId: string) {
    return this._cancelAbstractMessage(this._encryptionPublicKeyManager, msgId);
  }

  /**
   * Reject all unapproved messages of any type.
   *
   * @param reason - A message to indicate why.
   */
  rejectUnapproved(reason?: string) {
    Object.keys(
      this._encryptionPublicKeyManager.getUnapprovedMessages(),
    ).forEach((messageId) => {
      this._cancelAbstractMessage(
        this._encryptionPublicKeyManager,
        messageId,
        reason,
      );
    });
  }

  /**
   * Clears all unapproved messages from memory.
   */
  clearUnapproved() {
    this._encryptionPublicKeyManager.update({
      unapprovedMessages: {},
      unapprovedMessagesCount: 0,
    });
  }

  private _cancelAbstractMessage(
    messageManager: AbstractMessageManager<
      AbstractMessage,
      AbstractMessageParams,
      AbstractMessageParamsMetamask
    >,
    messageId: string,
    reason?: string,
  ) {
    if (reason) {
      this._metricsEvent({
        event: reason,
        category: MetaMetricsEventCategory.Messages,
        properties: {
          action: 'Encryption public key Request',
        },
      });
    }

    messageManager.rejectMessage(messageId);
    this._rejectApproval(messageId);

    return this._getState();
  }

  private _subscribeToMessageState(
    messageManager: AbstractMessageManager<
      AbstractMessage,
      AbstractMessageParams,
      AbstractMessageParamsMetamask
    >,
    updateState: (
      state: EncryptionPublicKeyControllerState,
      newMessages: Record<string, StateMessage>,
      messageCount: number,
    ) => void,
  ) {
    messageManager.subscribe((state: MessageManagerState<AbstractMessage>) => {
      const newMessages = this._migrateMessages(
        state.unapprovedMessages as any,
      );
      this.update((draftState) => {
        updateState(draftState, newMessages, state.unapprovedMessagesCount);
      });
    });
  }

  private _migrateMessages(
    coreMessages: Record<string, CoreMessage>,
  ): Record<string, StateMessage> {
    const stateMessages: Record<string, StateMessage> = {};

    for (const messageId of Object.keys(coreMessages)) {
      const coreMessage = coreMessages[messageId];
      const stateMessage = this._migrateMessage(coreMessage);
      stateMessages[messageId] = stateMessage;
    }

    return stateMessages;
  }

  private _migrateMessage(coreMessage: CoreMessage): StateMessage {
    const { messageParams, ...coreMessageData } = coreMessage;

    // Core message managers use messageParams but frontend uses msgParams with lots of references
    const stateMessage = {
      ...coreMessageData,
      rawSig: coreMessage.rawSig as string,
      msgParams: messageParams.from,
      origin: messageParams.origin,
    };

    return stateMessage;
  }

  private _requestApproval(
    msgParams: AbstractMessageParamsMetamask,
    type: string,
  ) {
    const id = msgParams.metamaskId as string;
    const origin = msgParams.origin || ORIGIN_METAMASK;

    this.messagingSystem
      .call(
        'ApprovalController:addRequest',
        {
          id,
          origin,
          type,
        },
        true,
      )
      .catch(() => {
        // Intentionally ignored as promise not currently used
      });
  }

  private _acceptApproval(messageId: string) {
    this.messagingSystem.call('ApprovalController:acceptRequest', messageId);
  }

  private _rejectApproval(messageId: string) {
    this.messagingSystem.call(
      'ApprovalController:rejectRequest',
      messageId,
      'Cancel',
    );
  }
}