// SPDX-License-Identifier: MIT
pragma solidity ^0.8.6;

import {CBORChainlink} from "../../vendor/CBORChainlink.sol";
import {BufferChainlink} from "../../vendor/BufferChainlink.sol";

/**
 * @title Library for Chainlink Functions
 */
library Functions {
  uint256 internal constant DEFAULT_BUFFER_SIZE = 256;

  using CBORChainlink for BufferChainlink.buffer;

  enum Location {
    Inline,
    Remote
  }

  enum CodeLanguage {
    JavaScript
    // In future version we may add other languages
  }

  struct Request {
    Location codeLocation;
    Location secretsLocation;
    CodeLanguage language;
    string source; // Source code for Location.Inline or url for Location.Remote
    bytes secrets; // Encrypted secrets blob for Location.Inline or url for Location.Remote
    string[] args;
  }

  error EmptySource();
  error EmptyUrl();
  error EmptySecrets();
  error EmptyArgs();

  /**
   * @notice Encodes a Request to CBOR encoded bytes
   * @param self The request to encode
   * @return CBOR encoded bytes
   */
  function encodeCBOR(Request memory self) internal pure returns (bytes memory) {
    BufferChainlink.buffer memory buf;
    BufferChainlink.init(buf, DEFAULT_BUFFER_SIZE);

    buf.encodeString("codeLocation");
    buf.encodeUInt(uint256(self.codeLocation));

    buf.encodeString("language");
    buf.encodeUInt(uint256(self.language));

    buf.encodeString("source");
    buf.encodeString(self.source);

    if (self.args.length > 0) {
      buf.encodeString("args");
      buf.startArray();
      for (uint256 i = 0; i < self.args.length; i++) {
        buf.encodeString(self.args[i]);
      }
      buf.endSequence();
    }

    if (self.secrets.length > 0) {
      buf.encodeString("secretsLocation");
      buf.encodeUInt(uint256(self.secretsLocation));
      buf.encodeString("secrets");
      buf.encodeBytes(self.secrets);
    }

    return buf.buf;
  }

  /**
   * @notice Initializes a Chainlink Functions Request
   * @dev Sets the codeLocation and code on the request
   * @param self The uninitialized request
   * @param location The user provided source code location
   * @param language The programming language of the user code
   * @param source The user provided source code or a url
   */
  function initializeRequest(
    Request memory self,
    Location location,
    CodeLanguage language,
    string memory source
  ) internal pure {
    if (bytes(source).length == 0) revert EmptySource();

    self.codeLocation = location;
    self.language = language;
    self.source = source;
  }

  /**
   * @notice Initializes a Chainlink Functions Request
   * @dev Simplified version of initializeRequest for PoC
   * @param self The uninitialized request
   * @param javaScriptSource The user provided JS code (must not be empty)
   */
  function initializeRequestForInlineJavaScript(Request memory self, string memory javaScriptSource) internal pure {
    initializeRequest(self, Location.Inline, CodeLanguage.JavaScript, javaScriptSource);
  }

  /**
   * @notice Adds Inline user encrypted secrets to a Request
   * @param self The initialized request
   * @param secrets The user encrypted secrets (must not be empty)
   */
  function addInlineSecrets(Request memory self, bytes memory secrets) internal pure {
    if (secrets.length == 0) revert EmptySecrets();

    self.secretsLocation = Location.Inline;
    self.secrets = secrets;
  }

  /**
   * @notice Adds Remote user encrypted secrets to a Request
   * @param self The initialized request
   * @param encryptedSecretsURLs Encrypted comma-separated string of URLs pointing to off-chain secrets
   */
  function addRemoteSecrets(Request memory self, bytes memory encryptedSecretsURLs) internal pure {
    if (encryptedSecretsURLs.length == 0) revert EmptySecrets();

    self.secretsLocation = Location.Remote;
    self.secrets = encryptedSecretsURLs;
  }

  /**
   * @notice Adds args for the user run function
   * @param self The initialized request
   * @param args The array of args (must not be empty)
   */
  function addArgs(Request memory self, string[] memory args) internal pure {
    if (args.length == 0) revert EmptyArgs();

    self.args = args;
  }
}