// libvle -- library for building Vim-like applications
// Copyright (C) 2022 xaizek <xaizek@posteo.net>
//
// This file is part of libvle.
//
// libvle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// libvle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with libvle.  If not, see <https://www.gnu.org/licenses/>.

#ifndef LIBVLE__COMMANDS_HPP__
#define LIBVLE__COMMANDS_HPP__

#include <deque>
#include <functional>
#include <string>
#include <vector>

namespace vle {

// A command.
struct Command
{
    // Canonical (the most complete) type of handler.
    using handler_t = void(const std::vector<std::string> &args);

    std::string abbr;  // Shortest name (prefix of the longest one).
    std::string name;  // Longest name.
    std::string descr; // Description of the command.

    int minArgs; // Minimal number of arguments (>= 0).
    int maxArgs; // Maximum number of arguments or a negative value (means
                 // "unlimited").

    std::function<handler_t> handler; // Handler to be called on match.
};

// Dispatches command-line commands.
class Commands
{
public:
    // Setups an empty state.
    Commands();
    ~Commands();

    Commands(const Commands &rhs) = delete;
    Commands(Commands &&rhs) = delete;
    Commands & operator=(const Commands &rhs) = delete;
    Commands & operator=(Commands &&rhs) = delete;

public:
    // Runs a command.  Returns `false` on error (from parser or handler).
    bool execute(const std::string &cmd);

    // Registers a shortcut.  Throws `std::invalid_argument` if shortcut is too
    // long or a duplicate.
    void addCommand(Command cmd);

private:
    // Prepares engine for use of this set of commands.
    void setup();

private:
    std::deque<Command> commands; // List of registered commands.
    void *cmds_conf;              // Settings for the cmds unit.
};

}

#endif // LIBVLE__COMMANDS_HPP__