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export const handler = async () => {
  return {
    statusCode: 200,
    body: JSON.stringify({
      method: "setTime",
      args: [new Date().valueOf()],
      maxGas: "100000000000000", // 0.0001 ETH
      abort: false,
    }),
  };
};

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract Time {
    uint256 timestamp;
    event TimeRequest();

    /**
     * Emit and event that will be picked up by the Kenshi
     * Oracle Network and sent to your oracle for processing
     */
    function requestTime() external {
        emit TimeRequest();
    }

    /**
     * This method will be called by the Kenshi Oracle Network
     * with the result returned from your oracle
     */
    function setTime(uint256 time) external {
        timestamp = time;
    }

    /**
     * Public function to display the last retrieved timestamp
     */
    function showTime() public view returns (uint256) {
        return timestamp;
    }
}

import { ethers } from "ethers";
import fetch from "node-fetch";

const url =
  "https://api.coingecko.com/api/v3/coins/kenshi/market_chart?vs_currency=usd&days=1";

export const handler = async () => {
  const resp = await fetch(url);
  const { prices } = await resp.json();
  const average =
    prices
      .slice(-6) // last 30 minutes
      .map(([_, price]) => price)
      .reduce((a, b) => a + b) / 6;
  return {
    statusCode: 200,
    body: JSON.stringify({
      method: "setPrice",
      args: [ethers.utils.parseUnits(average.toFixed(18)).toString()],
      maxGas: "100000000000000", // 0.0001 ETH
      abort: false,
    }),
  };
};

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract Price {
    event PriceRequest();
    event PriceRequestFulfilled(uint256 price);

    /**
     * Emit and event that will be picked up by the Kenshi
     * Oracle Network and sent to your oracle for processing
     */
    function requestPrice() external {
        emit PriceRequest();
    }

    /**
     * This method will be called by the Kenshi Oracle Network
     * with the result returned from your oracle
     */
    function setPrice(uint256 price) external {
        emit PriceRequestFulfilled(price);
    }
}

import { ethers } from "ethers";

const abi = ["function balanceOf(address) view returns (uint)"];

export const handler = async ({ body }) => {
  const { entry } = JSON.parse(body);
  const provider = new ethers.providers.JsonRpcProvider(process.env.RPC_ADDR);
  const contract = new ethers.Contract(entry.event.args.token, abi, provider);
  const balance = await contract.balanceOf(entry.event.args.user);
  return {
    statusCode: 200,
    body: JSON.stringify({
      method: "setBalance",
      args: [entry.event.args.user, entry.event.args.token, balance.toString()],
      maxGas: "100000000000000", // 0.0001 ETH
      abort: false,
    }),
  };
};

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract Balance {
    event BalanceRequest(address user, address token);
    event BalanceRequestFulfilled(address user, address token, uint256 balance);

    /**
     * Emit and event that will be picked up by the Kenshi
     * Oracle Network and sent to your oracle for processing
     */
    function requestBalance(address user, address token) external {
        emit BalanceRequest(user, token);
    }

    /**
     * This method will be called by the Kenshi Oracle Network
     * with the result returned from your oracle
     */
    function setBalance(
        address user,
        address token,
        uint256 balance
    ) external {
        emit BalanceRequestFulfilled(user, token, balance);
    }
}

import { ethers } from "ethers";
import fetch from "node-fetch";

export const handler = async ({ body }) => {
  const now = new Date();
  const { entry } = JSON.parse(body);
  // Solidity doesn't have floating point numbers;
  // We divide lat and long by 100 for 0.01 precision
  const lat = ethers.BigNumber.from(entry.event.args.lat).toNumber() / 100;
  const long = ethers.BigNumber.from(entry.event.args.long).toNumber() / 100;
  const url = `https://api.brightsky.dev/weather?lat=${lat}&lon=${long}&date=${now.toISOString()}`;
  const resp = await fetch(url);
  const { weather } = await resp.json();
  return {
    statusCode: 200,
    body: JSON.stringify({
      method: "setWeather",
      args: [
        entry.event.args.lat,
        entry.event.args.long,
        // Solidity doesn't have floating point numbers;
        // We multiply the temperature by 100 for 0.01 precision
        Math.round(weather[0].temperature * 100),
      ],
      maxGas: "100000000000000", // 0.0001 ETH
      abort: false,
    }),
  };
};

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract Weather {
    event WeatherRequest(uint256 lat, uint256 long);
    event WeatherRequestFulfilled(
        uint256 lat,
        uint256 long,
        uint256 temperature
    );

    /**
     * Emit and event that will be picked up by the Kenshi
     * Oracle Network and sent to your oracle for processing
     *
     * Note: Solidity doesn't have floating point numbers,
     * we assume lat and long are multiplied by 100 to elliminate
     * the decimal part of them
     */
    function requestWeather(uint256 lat, uint256 long) external {
        emit WeatherRequest(lat, long);
    }

    /**
     * This method will be called by the Kenshi Oracle Network
     * with the result returned from your oracle
     */
    function setWeather(
        uint256 lat,
        uint256 long,
        uint256 temperature
    ) external {
        emit WeatherRequestFulfilled(lat, long, temperature);
    }
}

import { decode, prove, getFastVerifyComponents } from "@kenshi.io/node-ecvrf";
import { createHash } from "crypto";
import Elliptic from "elliptic";

const EC = new Elliptic.ec("secp256k1");

export const getPublicKey = (privateKey) => {
  const key = EC.keyFromPrivate(privateKey);
  return {
    key: key.getPublic("hex"),
    compressed: key.getPublic(true, "hex"),
    x: key.getPublic().getX(),
    y: key.getPublic().getY(),
  };
};

const fromHex = (hex) => Buffer.from(hex.slice(2));

const hash = (...args) => {
  const sha256 = createHash("sha256");
  for (const arg of args) {
    sha256.update(arg);
  }
  return sha256.digest().toString("hex");
};

export const handler = async ({ body }) => {
  const { entry } = JSON.parse(body);

  // You can generate a private key using the `keygen` function
  // exported by the @kenshi.io/node-ecvrf library
  const publicKey = getPublicKey(process.env.VRF_PRIVATE_KEY);

  const alpha = hash(
    fromHex(entry.transaction.hash),
    fromHex(entry.log.index),
    fromHex(entry.block.address),
    fromHex(entry.event.args.requestId)
  );

  const proof = prove(process.env.VRF_PRIVATE_KEY, alpha);
  const fast = getFastVerifyComponents(publicKey.key, proof, alpha);
  const [Gamma, c, s] = decode(proof);

  return {
    statusCode: 200,
    body: JSON.stringify({
      method: "setRandomness",
      args: [
        [Gamma.x.toString(), Gamma.y.toString(), c.toString(), s.toString()],
        `0x${alpha}`,
        [fast.uX, fast.uY],
        [fast.sHX, fast.sHY, fast.cGX, fast.cGY],
        entry.event.args.requestId,
      ],
      maxGas: "100000000000000", // 0.0001 ETH
      abort: false,
    }),
  };
};

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

import "@kenshi.io/vrf-consumer/contracts/VRFUtils.sol";

contract VRFOracle {
    uint256 _requestId;
    mapping(uint256 => bool) alreadyFulfilled;

    event RandomnessRequest(uint256 requestId);
    event RandomnessRequestFulfilled(uint256 requestId, uint256 randomness);

    VRFUtils utils;

    constructor(bytes memory publicKey) {
        utils = new VRFUtils();
        utils.setPublicKey(publicKey);
    }

    /**
     * Emit and event that will be picked up by the Kenshi
     * Oracle Network and sent to your oracle for processing
     */
    function requestRandomness() external {
        emit RandomnessRequest(_requestId++);
    }

    /**
     * This method will be called by the Kenshi Oracle Network
     * with the result returned from your oracle
     *
     * Note: We encourage reading IETF ECVRF drafts to understand
     * what's going on: https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-vrf
     */
    function setRandomness(
        uint256[4] memory proof,
        bytes memory message,
        uint256[2] memory uPoint,
        uint256[4] memory vComponents,
        uint256 requestId
    ) external {
        require(!alreadyFulfilled[requestId], "Already fulfilled");
        bool isValid = utils.fastVerify(proof, message, uPoint, vComponents);
        require(isValid, "Cannot verify VRF results");
        bytes32 beta = utils.gammaToHash(proof[0], proof[1]);
        uint256 randomness = uint256(beta);
        alreadyFulfilled[requestId] = true;
        emit RandomnessRequestFulfilled(requestId, randomness);
    }
}