/*  Importing this library provides react native with a secure random source.
For more information, "visit https://docs.ethers.org/v5/cookbook/react-native/#cookbook-reactnative-security" */
import 'react-native-get-random-values';
import '@ethersproject/shims';

import { Wallet, utils } from 'ethers';
import { HDNode } from 'ethers/lib/utils';
import {
  setInternetCredentials,
  getInternetCredentials,
  resetInternetCredentials,
} from 'react-native-keychain';

import { AccountData, Secp256k1HdWallet } from '@cosmjs/amino';
import { stringToPath } from '@cosmjs/crypto';

import { Account, SignMessageParams, WalletDetails } from './types';

const createWallet = async (): Promise<WalletDetails> => {
  try {
    const mnemonic = utils.entropyToMnemonic(utils.randomBytes(16));
    await setInternetCredentials('mnemonicServer', 'mnemonic', mnemonic);

    const hdNode = HDNode.fromMnemonic(mnemonic);
    const ethNode = hdNode.derivePath("m/44'/60'/0'/0/0");
    const cosmosNode = hdNode.derivePath("m/44'/118'/0'/0/0");

    const ethAddress = ethNode.address;
    const cosmosAddress = (await getCosmosAccounts(mnemonic, 0)).data.address;

    await setInternetCredentials(
      'eth:keyServer:0',
      'eth:key:0',
      ethNode.privateKey,
    );
    await setInternetCredentials(
      'cosmos:keyServer:0',
      'cosmos:key:0',
      cosmosNode.privateKey,
    );

    await setInternetCredentials('eth:accountIndices', 'ethAccount', '0');
    await setInternetCredentials('cosmos:accountIndices', 'cosmosAccount', '0');

    const ethAccounts = {
      id: 0,
      pubKey: ethNode.publicKey,
      address: ethAddress,
    };

    const cosmosAccounts = {
      id: 0,
      pubKey: cosmosNode.publicKey,
      address: cosmosAddress,
    };

    return { mnemonic, ethAccounts, cosmosAccounts };
  } catch (error) {
    console.error('Error creating HD wallet:', error);
    return { mnemonic: '', ethAccounts: undefined, cosmosAccounts: undefined };
  }
};

const addAccount = async (network: string): Promise<Account | undefined> => {
  try {
    const mnemonicStore = await getInternetCredentials('mnemonicServer');
    if (!mnemonicStore) {
      throw new Error('Mnemonic not found!');
    }

    const mnemonic = mnemonicStore.password;
    const hdNode = HDNode.fromMnemonic(mnemonic);

    const idStore = await getInternetCredentials(`${network}:accountIndices`);
    if (!idStore) {
      throw new Error('Account id not found');
    }

    const accountIds = idStore.password;
    const ids = accountIds.split(',').map(Number);
    const id = ids[ids.length - 1] + 1;

    const derivationPath =
      network === 'eth' ? `m/44'/60'/0'/0/${id}` : `m/44'/118'/0'/0/${id}`;

    const node = hdNode.derivePath(derivationPath);
    const privKey = node.privateKey;
    const pubKey = node.publicKey;

    let address: string;

    switch (network) {
      case 'eth':
        address = node.address;
        break;
      case 'cosmos':
        address = (await getCosmosAccounts(mnemonic, id)).data.address;
        break;
      default:
        throw new Error('Invalid wallet type');
    }

    await setInternetCredentials(
      `${network}:keyServer:${id}`,
      `${network}:key:${id}`,
      privKey,
    );

    const accountIndicesKey = `${network}:accountIndices`;
    const accountIndices = await getInternetCredentials(accountIndicesKey);

    if (!accountIndices) {
      throw new Error('Account not found!');
    }
    let indices = accountIndices.password;
    indices += `,${id.toString()}`;

    await resetInternetCredentials(accountIndicesKey);
    await setInternetCredentials(
      accountIndicesKey,
      `${network}Account`,
      indices,
    );

    return { pubKey, address, id };
  } catch (error) {
    console.error('Error creating account:', error);
  }
};

const signMessage = async ({
  message,
  network,
  accountId,
}: SignMessageParams): Promise<string | undefined> => {
  switch (network) {
    case 'eth':
      return await signEthMessage(message, accountId);
    case 'cosmos':
      return await signCosmosMessage(message, accountId);
    default:
      throw new Error('Invalid wallet type');
  }
};

const signEthMessage = async (
  message: string,
  id: number,
): Promise<string | undefined> => {
  try {
    const keyCred = await getInternetCredentials(`eth:keyServer:${id}`);

    if (!keyCred) {
      throw new Error('Failed to retrieve internet credentials');
    }

    const wallet = new Wallet(keyCred.password);
    const signature = await wallet.signMessage(message);

    return signature;
  } catch (error) {
    console.error('Error signing Ethereum message:', error);
    return undefined;
  }
};

const signCosmosMessage = async (
  message: string,
  id: number,
): Promise<string | undefined> => {
  try {
    const mnemonicStore = await getInternetCredentials('mnemonicServer');

    if (!mnemonicStore) {
      throw new Error('Mnemonic not found');
    }

    const mnemonic = mnemonicStore.password;
    const cosmosAccount = await getCosmosAccounts(mnemonic, id);
    const cosmosSignature = await cosmosAccount.cosmosWallet.signAmino(
      cosmosAccount.data.address,
      {
        chain_id: '',
        account_number: '0',
        sequence: '0',
        fee: {
          gas: '0',
          amount: [],
        },
        msgs: [
          {
            type: 'sign/MsgSignData',
            value: {
              signer: cosmosAccount.data.address,
              data: btoa(message),
            },
          },
        ],
        memo: '',
      },
    );

    return cosmosSignature.signature.signature;
  } catch (error) {
    console.error('Error signing Cosmos message:', error);
    return undefined;
  }
};

const getCosmosAccounts = async (
  mnemonic: string,
  id: number,
): Promise<{ cosmosWallet: Secp256k1HdWallet; data: AccountData }> => {
  const cosmosWallet = await Secp256k1HdWallet.fromMnemonic(mnemonic, {
    hdPaths: [stringToPath(`m/44'/118'/0'/0/${id}`)],
  });

  const accountsData = await cosmosWallet.getAccounts();
  const data = accountsData[0];

  return { cosmosWallet, data };
};

const resetKeyServers = async (prefix: string) => {
  const idStore = await getInternetCredentials(`${prefix}:accountIndices`);
  if (!idStore) {
    throw new Error('Account id not found.');
  }

  const accountIds = idStore.password;
  const ids = accountIds.split(',').map(Number);
  const id = ids[ids.length - 1];

  for (let i = 0; i <= id; i++) {
    await resetInternetCredentials(`${prefix}:keyServer:${i}`);
  }
};

const resetWallet = async () => {
  try {
    await resetInternetCredentials('mnemonicServer');

    await resetKeyServers('eth');
    await resetKeyServers('cosmos');

    await resetInternetCredentials('eth:accountIndices');
    await resetInternetCredentials('cosmos:accountIndices');
  } catch (error) {
    console.error('Error resetting wallet:', error);
    throw error;
  }
};

export { createWallet, addAccount, signMessage, resetWallet };