/*
 This file is part of GNU Taler
 (C) 2019 GNUnet e.V.

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

/**
 * Entry-point for the wallet under qtart, the QuckJS-based GNU Taler runtime.
 */

/**
 * Imports.
 */
import {
  CoreApiMessageEnvelope,
  CoreApiResponse,
  CoreApiResponseSuccess,
  getErrorDetailFromException,
  InitRequest,
  j2s,
  Logger,
  setGlobalLogLevelFromString,
  WalletNotification,
} from "@gnu-taler/taler-util";
import { createPlatformHttpLib } from "@gnu-taler/taler-util/http";
import { qjsOs } from "@gnu-taler/taler-util/qtart";
import {
  createNativeWalletHost2,
  DefaultNodeWalletArgs,
  openPromise,
  Wallet,
  WalletApiOperation,
} from "@gnu-taler/taler-wallet-core";
import {
  reduceAction,
  getBackupStartState,
  getRecoveryStartState,
  discoverPolicies,
  mergeDiscoveryAggregate,
} from "@gnu-taler/anastasis-core";
import { userIdentifierDerive } from "@gnu-taler/anastasis-core/lib/crypto.js";

setGlobalLogLevelFromString("trace");

const logger = new Logger("taler-wallet-embedded/index.ts");

/**
 * Sends JSON to the host application, i.e. the process that
 * runs the JavaScript interpreter (quickjs / qtart) to run
 * the embedded wallet.
 */
function sendNativeMessage(ev: CoreApiMessageEnvelope): void {
  const m = JSON.stringify(ev);
  qjsOs.postMessageToHost(m);
}

class NativeWalletMessageHandler {
  walletArgs: DefaultNodeWalletArgs | undefined;
  initRequest: InitRequest = {};
  maybeWallet: Wallet | undefined;
  wp = openPromise<Wallet>();
  httpLib = createPlatformHttpLib();

  /**
   * Handle a request from the native wallet.
   */
  async handleMessage(
    operation: string,
    id: string,
    args: any,
  ): Promise<CoreApiResponse> {
    const wrapSuccessResponse = (result: unknown): CoreApiResponseSuccess => {
      return {
        type: "response",
        id,
        operation,
        result,
      };
    };

    let initResponse: any = {};

    const reinit = async () => {
      logger.info("in reinit");
      const wR = await createNativeWalletHost2(this.walletArgs);
      const w = wR.wallet;
      this.maybeWallet = w;
      const resp = await w.handleCoreApiRequest("initWallet", "native-init", {
        ...this.initRequest,
      });
      initResponse = resp.type == "response" ? resp.result : resp.error;
      w.runTaskLoop().catch((e) => {
        logger.error(
          `Error during wallet retry loop: ${e.stack ?? e.toString()}`,
        );
      });
      this.wp.resolve(w);
    };

    switch (operation) {
      case "init": {
        this.initRequest = {
          ...args,
        };
        this.walletArgs = {
          notifyHandler: async (notification: WalletNotification) => {
            sendNativeMessage({ type: "notification", payload: notification });
          },
          persistentStoragePath: args.persistentStoragePath,
          httpLib: this.httpLib,
          cryptoWorkerType: args.cryptoWorkerType,
        };
        const logLevel = args.logLevel;
        if (logLevel) {
          setGlobalLogLevelFromString(logLevel);
        }
        await reinit();
        return wrapSuccessResponse({
          ...initResponse,
        });
      }
      case "startTunnel": {
        // this.httpLib.useNfcTunnel = true;
        throw Error("not implemented");
      }
      case "stopTunnel": {
        // this.httpLib.useNfcTunnel = false;
        throw Error("not implemented");
      }
      case "tunnelResponse": {
        // httpLib.handleTunnelResponse(msg.args);
        throw Error("not implemented");
      }
      case "reset": {
        logger.info("resetting wallet");
        const oldArgs = this.walletArgs;
        this.walletArgs = { ...oldArgs };
        if (oldArgs && oldArgs.persistentStoragePath) {
          const ret = qjsOs.remove(oldArgs.persistentStoragePath);
          if (ret != 0) {
            logger.error("removing DB file failed");
          }
          // Prevent further storage!
          this.walletArgs.persistentStoragePath = undefined;
        }
        const wallet = await this.wp.promise;
        wallet.stop();
        this.wp = openPromise<Wallet>();
        this.maybeWallet = undefined;
        await reinit();
        logger.info("wallet re-initialized after reset");
        return wrapSuccessResponse({});
      }
      default: {
        const wallet = await this.wp.promise;
        return await wallet.handleCoreApiRequest(operation, id, args);
      }
    }
  }
}

/**
 * Handle an Anastasis request from the native app.
 */
async function handleAnastasisRequest(
  operation: string,
  id: string,
  args: any,
): Promise<CoreApiResponse> {
  const wrapSuccessResponse = (result: unknown): CoreApiResponseSuccess => {
    return {
      type: "response",
      id,
      operation,
      result,
    };
  };

  let req = args ?? {};

  switch (operation) {
    case "anastasisReduce":
      // TODO: do some input validation here
      let reduceRes = await reduceAction(req.state, req.action, req.args ?? {});
      // For now, this will return "success" even if the wrapped Anastasis
      // response is a ReducerStateError.
      return wrapSuccessResponse(reduceRes);
    case "anastasisStartBackup":
      return wrapSuccessResponse(await getBackupStartState());
    case "anastasisStartRecovery":
      return wrapSuccessResponse(await getRecoveryStartState());
    case "anastasisDiscoverPolicies":
      let discoverRes = await discoverPolicies(req.state, req.cursor);
      let aggregatedPolicies = mergeDiscoveryAggregate(
        discoverRes.policies ?? [],
        req.state.discoveryState?.aggregatedPolicies ?? [],
      );
      return wrapSuccessResponse({
        ...req.state,
        discoveryState: {
          state: "finished",
          aggregatedPolicies,
          cursor: discoverRes.cursor,
        },
      });
    default:
      throw Error("unsupported anastasis operation");
  }
}

export function installNativeWalletListener(): void {
  setGlobalLogLevelFromString("trace");
  const handler = new NativeWalletMessageHandler();
  const onMessage = async (msgStr: any): Promise<void> => {
    if (typeof msgStr !== "string") {
      logger.error("expected string as message");
      return;
    }
    const msg = JSON.parse(msgStr);
    const operation = msg.operation;
    if (typeof operation !== "string") {
      logger.error(
        "message to native wallet helper must contain operation of type string",
      );
      return;
    }
    const id = msg.id;
    logger.info(`native listener: got request for ${operation} (${id})`);

    let respMsg: CoreApiResponse;
    try {
      if (msg.operation.startsWith("anastasis")) {
        respMsg = await handleAnastasisRequest(operation, id, msg.args ?? {});
      } else {
        respMsg = await handler.handleMessage(operation, id, msg.args ?? {});
      }
    } catch (e) {
      respMsg = {
        type: "error",
        id,
        operation,
        error: getErrorDetailFromException(e),
      };
    }
    logger.info(
      `native listener: sending back ${respMsg.type} message for operation ${operation} (${id})`,
    );
    sendNativeMessage(respMsg);
  };

  qjsOs.setMessageFromHostHandler((m) => onMessage(m));

  logger.info("native wallet listener installed");
}

// @ts-ignore
globalThis.installNativeWalletListener = installNativeWalletListener;

export async function testWithGv() {
  const w = await createNativeWalletHost2({
    config: {
      features: {
        allowHttp: true,
      },
    },
  });
  await w.wallet.client.call(WalletApiOperation.InitWallet, {});
  await w.wallet.client.call(WalletApiOperation.RunIntegrationTest, {
    amountToSpend: "KUDOS:1",
    amountToWithdraw: "KUDOS:3",
    bankAccessApiBaseUrl:
      "https://bank.demo.taler.net/demobanks/default/access-api/",
    exchangeBaseUrl: "https://exchange.demo.taler.net/",
    merchantBaseUrl: "https://backend.demo.taler.net/",
  });
  await w.wallet.runTaskLoop({
    stopWhenDone: true,
  });
}

export async function testWithLocal(path: string) {
  console.log("running local test");
  const w = await createNativeWalletHost2({
    persistentStoragePath: path ?? "walletdb.json",
    config: {
      features: {
        allowHttp: true,
      },
    },
  });
  console.log("created wallet");
  await w.wallet.client.call(WalletApiOperation.InitWallet, {
    skipDefaults: true,
  });
  console.log("initialized wallet");
  await w.wallet.client.call(WalletApiOperation.RunIntegrationTest, {
    amountToSpend: "TESTKUDOS:1",
    amountToWithdraw: "TESTKUDOS:3",
    bankAccessApiBaseUrl: "http://localhost:8082/taler-bank-access/",
    exchangeBaseUrl: "http://localhost:8081/",
    merchantBaseUrl: "http://localhost:8083/",
  });
  console.log("started integration test");
  await w.wallet.runTaskLoop({
    stopWhenDone: true,
  });
  console.log("done with task loop");
  w.wallet.stop();
  console.log("DB stats:", j2s(w.getDbStats()));
}

export async function testArgon2id() {
  const userIdVector = {
    input_id_data: {
      name: "Fleabag",
      ssn: "AB123",
    },
    input_server_salt: "FZ48EFS7WS3R2ZR4V53A3GFFY4",
    output_id:
      "YS45R6CGJV84K1NN7T14ZBCPVTZ6H15XJSM1FV0R748MHPV82SM0126EBZKBAAGCR34Q9AFKPEW1HRT2Q9GQ5JRA3642AB571DKZS18",
  };

  if (
    (await userIdentifierDerive(
      userIdVector.input_id_data,
      userIdVector.input_server_salt,
    )) != userIdVector.output_id
  ) {
    throw Error("argon2id is not working!");
  }

  console.log("argon2id is working!");
}

// @ts-ignore
globalThis.testWithGv = testWithGv;
// @ts-ignore
globalThis.testWithLocal = testWithLocal;
// @ts-ignore
globalThis.testArgon2id = testArgon2id;
// @ts-ignore
globalThis.testReduceAction = reduceAction;
// @ts-ignore
globalThis.testDiscoverPolicies = discoverPolicies;