//////////////////////////////////////////////////////
//
// LuaConsole:
//
// Used to parse commands that are being interactively typed
// in by a user.  The common usage pattern is:
//
//    1. Print the prompt suggested by 'get_prompt'.
//    2. Read a line of text from stdin.
//    3. Add the line to the LuaConsole using 'add'.
//    4. Get the command words using 'get_command'.
//    5. If the command is empty, do nothing.
//    6. If the command is nonempty, execute it and call 'clear'.
//
// The 'words' returned by the luaconsole can be empty, meaning
// that there's no command to execute.  If the words are nonempty,
// then the first word is the command.  There are two hardwired
// commands:
//
//    lua <expr> - execute a lua expression
//    syntax <message> - print a syntax error message
//
// If the first word is anything else, it means the user typed
// that word on the command line.   It is up to you to interpret
// such commands.
//
//////////////////////////////////////////////////////

#ifndef LUACONSOLE_HPP
#define LUACONSOLE_HPP

#include <string>
#include "luastack.hpp"

class LuaConsole {
public:
    using StringVec = std::vector<std::string>;

private:
    lua_State *lua_state_;
    std::string raw_input_;
    int lines_;
    StringVec words_;
    std::string prompt_;

    void clear_raw_input();

public:
    LuaConsole();
    ~LuaConsole();

    // Fetch the recommended prompt.
    //
    // You should update the prompt immediately after 'add'.
    //
    const std::string &get_prompt() { return prompt_; }
    
    // Fetch the command to execute.
    //
    // You should fetch the command after calling 'add'.
    // Returns the empty vector if there is no command.
    // If there is a command, the first word is the command word.
    // See the file comment for certain built-in command words.
    // 
    StringVec get_command();

    // Add a line of text that was just read from the console.
    //
    void add(std::string line);

};

#endif // LUACONSOLE_HPP