message.h

/*
 * Header for the Message class.
 * Represents a single message (request or response) in the network protocol.
 * 
 * CSF Assignment 5
 * 
 * Ifrah Attar - iattar1@jh.edu
 * Morgan Huberty - mhubert3@jh.edu
 * 
 */

 #ifndef MESSAGE_H
 #define MESSAGE_H
 
 #include <vector>
 #include <string>
 
 /**
  * @enum MessageType
  * @brief Enumerates the different types of messages in the protocol.
  */
 enum class MessageType {
   // Used only for uninitialized Message objects
   NONE,
 
   // Requests
   LOGIN, CREATE, PUSH, POP, TOP, SET, GET, ADD, SUB, MUL, DIV, BEGIN, COMMIT, BYE,
 
   // Responses
   OK, FAILED, ERROR, DATA,
 };
 
 /**
  * @class Message
  * @brief Represents a single protocol message.
  *
  * This class encapsulates the type and arguments of a message and provides
  * methods to access its components and validate its structure according
  * to the key/value store protocol.
  */
 class Message {
 private:
   MessageType m_message_type;
   std::vector<std::string> m_args;
 
 public:
   // Maximum encoded message length (including terminator newline character)
   static const unsigned MAX_ENCODED_LEN = 1024;
 
   /**
    * @brief Default constructor. Creates a message of type NONE.
    */
   Message();
 
   /**
    * @brief Constructs a message with a specific type and arguments.
    * @param message_type The type of the message.
    * @param args An initializer list of string arguments for the message.
    */
   Message( MessageType message_type, std::initializer_list<std::string> args = std::initializer_list<std::string>() );
 
   /**
    * @brief Copy constructor.
    * @param other The Message object to copy.
    */
   Message( const Message &other );
 
   /**
    * @brief Destructor.
    */
   ~Message();
 
   /**
    * @brief Assignment operator.
    * @param rhs The Message object to assign from.
    * @return A reference to this Message object.
    */
   Message &operator=( const Message &rhs );
 
   /**
    * @brief Gets the type of the message.
    * @return The MessageType of this message.
    */
   MessageType get_message_type() const;
 
   /**
    * @brief Sets the type of the message.
    * @param message_type The new MessageType for this message.
    */
   void set_message_type( MessageType message_type );
 
   /**
    * @brief Gets the username from a LOGIN message.
    * @return The username string.
    */
   std::string get_username() const;
 
   /**
    * @brief Gets the table name from a CREATE, SET, or GET message.
    * @return The table name string.
    */
   std::string get_table() const;
 
   /**
    * @brief Gets the key from a SET or GET message.
    * @return The key string.
    */
   std::string get_key() const;
 
   /**
    * @brief Gets the value from a PUSH or DATA message.
    * @return The value string.
    */
   std::string get_value() const;
 
   /**
    * @brief Gets the quoted text from a FAILED or ERROR message.
    * @return The text content of the response.
    */
   std::string get_quoted_text() const;
 
   /**
    * @brief Adds an argument to the message's argument list.
    * @param arg The string argument to add.
    */
   void push_arg( const std::string &arg );
 
   /**
    * @brief Validates the message against the protocol specification.
    * @return True if the message has the correct number and type of arguments
    *         for its MessageType, false otherwise.
    */
   bool is_valid() const;
 
   /**
    * @brief Gets the number of arguments.
    * @return The number of arguments in the message.
    */
   unsigned get_num_args() const { return m_args.size(); }
 
   /**
    * @brief Gets a specific argument by index.
    * @param i The index of the argument to retrieve.
    * @return The argument string at the specified index.
    */
   std::string get_arg( unsigned i ) const { return m_args.at( i ); }
 };
 
 #endif // MESSAGE_H