// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {CBOR} from "../../../../vendor/solidity-cborutils/v2.0.0/CBOR.sol";

/// @title Library for encoding the input data of a Functions request into CBOR
library FunctionsRequest {
  using CBOR for CBOR.CBORBuffer;

  uint16 public constant REQUEST_DATA_VERSION = 1;
  uint256 internal constant DEFAULT_BUFFER_SIZE = 256;

  enum Location {
    Inline, // Provided within the Request
    Remote, // Hosted through remote location that can be accessed through a provided URL
    DONHosted // Hosted on the DON's storage

  }

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

  struct Request {
    Location codeLocation; // ════════════╸ The location of the source code that will be
      // executed on each node in the DON
    Location secretsLocation; // ═════════╸ The location of secrets that will be passed into the
      // source code. *Only Remote secrets are supported
    CodeLanguage language; // ════════════╸ The coding language that the source code is written in
    string source; // ════════════════════╸ Raw source code for
      // Request.codeLocation of Location.Inline, URL for Request.codeLocation of Location.Remote, or slot decimal
      // number for Request.codeLocation of Location.DONHosted
    bytes encryptedSecretsReference; // ══╸ Encrypted URLs for Request.secretsLocation of Location.Remote (use
      // addSecretsReference()), or CBOR encoded slotid+version for Request.secretsLocation of Location.DONHosted (use
      // addDONHostedSecrets())
    string[] args; // ════════════════════╸ String arguments that will be passed into the source code
    bytes[] bytesArgs; // ════════════════╸ Bytes arguments that will be passed into the source code
  }

  error EmptySource();
  error EmptySecrets();
  error EmptyArgs();
  error NoInlineSecrets();

  /// @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) {
    CBOR.CBORBuffer memory buffer = CBOR.create(DEFAULT_BUFFER_SIZE);

    buffer.writeString("codeLocation");
    buffer.writeUInt256(uint256(self.codeLocation));

    buffer.writeString("language");
    buffer.writeUInt256(uint256(self.language));

    buffer.writeString("source");
    buffer.writeString(self.source);

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

    if (self.encryptedSecretsReference.length > 0) {
      if (self.secretsLocation == Location.Inline) {
        revert NoInlineSecrets();
      }
      buffer.writeString("secretsLocation");
      buffer.writeUInt256(uint256(self.secretsLocation));
      buffer.writeString("secrets");
      buffer.writeBytes(self.encryptedSecretsReference);
    }

    if (self.bytesArgs.length > 0) {
      buffer.writeString("bytesArgs");
      buffer.startArray();
      for (uint256 i = 0; i < self.bytesArgs.length; ++i) {
        buffer.writeBytes(self.bytesArgs[i]);
      }
      buffer.endSequence();
    }

    return buffer.buf.buf;
  }

  /// @notice Initializes a Chainlink Functions Request
  /// @dev Sets the codeLocation and code on the request
  /// @param self The uninitialized request
  /// @param codeLocation 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 codeLocation,
    CodeLanguage language,
    string memory source
  ) internal pure {
    if (bytes(source).length == 0) revert EmptySource();

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

    self.secretsLocation = Location.Remote;
    self.encryptedSecretsReference = encryptedSecretsReference;
  }

  /// @notice Adds DON-hosted secrets reference to a Request
  /// @param self The initialized request
  /// @param slotID Slot ID of the user's secrets hosted on DON
  /// @param version User data version (for the slotID)
  function _addDONHostedSecrets(Request memory self, uint8 slotID, uint64 version) internal pure {
    CBOR.CBORBuffer memory buffer = CBOR.create(DEFAULT_BUFFER_SIZE);

    buffer.writeString("slotID");
    buffer.writeUInt64(slotID);
    buffer.writeString("version");
    buffer.writeUInt64(version);

    self.secretsLocation = Location.DONHosted;
    self.encryptedSecretsReference = buffer.buf.buf;
  }

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

    self.args = args;
  }

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

    self.bytesArgs = args;
  }
}