// Copyright (C) 2015 xaizek <xaizek@posteo.net>
//
// This file is part of dit.
//
// dit is free software: you can redistribute it and/or modify
// it under the terms of version 3 of the GNU Affero General Public
// License as published by the Free Software Foundation.
//
// dit 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 dit.  If not, see <http://www.gnu.org/licenses/>.

#ifndef DIT__COMMAND_HPP__
#define DIT__COMMAND_HPP__

#include <iosfwd>
#include <string>
#include <vector>

#include <boost/optional.hpp>

#include "utils/Passkey.hpp"

class Dit;
class Project;
class Tests;

/**
 * @brief Base class for sub-commands.
 */
class Command
{
protected:
    /**
     * @brief Constructs sub-command.
     *
     * @param name Name that will be checked against and displayed.
     * @param descr Short description.
     * @param help Long description.
     */
    Command(std::string name, std::string descr, std::string help);

public:
    /**
     * @brief Properly destructs objects of derived classes.
     */
    virtual ~Command();

public:
    /**
     * @brief Gets name of the command to match against and to display.
     *
     * @returns The name.
     */
    std::string getName() const;
    /**
     * @brief Gets short description of the command for lists.
     *
     * @returns The description.
     */
    std::string getDescr() const;
    /**
     * @brief Gets long description of the command for detailed help.
     *
     * @returns The description.
     */
    std::string getHelp() const;

public:
    /**
     * @brief Executes generic command (no project) with specified arguments.
     *
     * @param dit Application instance.
     * @param args List of arguments for the command.
     *
     * @returns Exit code suitable for returning it from @c main() or empty
     *          value if not implemented.
     */
    virtual boost::optional<int> run(Dit &dit,
                                     const std::vector<std::string> &args);
    /**
     * @brief Executes project command with specified arguments.
     *
     * @param project Project to perform operation on.
     * @param args List of arguments for the command.
     *
     * @returns Exit code suitable for returning it from @c main() or empty
     *          value if not implemented.
     */
    virtual boost::optional<int> run(Project &project,
                                     const std::vector<std::string> &args);

    /**
     * @brief Asks for generic command (no project) argument completion.
     *
     * @param dit Application instance.
     * @param args List of arguments for the command.
     *
     * @returns Exit code suitable for returning it from @c main() or empty
     *          value if not implemented.
     */
    virtual boost::optional<int> complete(Dit &dit,
                                          const std::vector<std::string> &args);
    /**
     * @brief Asks for possibly project-specific argument completion.
     *
     * @param project Project to perform operation on.
     * @param args List of arguments for the command.
     *
     * @returns Exit code suitable for returning it from @c main() or empty
     *          value if not implemented.
     */
    virtual boost::optional<int> complete(Project &project,
                                          const std::vector<std::string> &args);

public:
    /**
     * @brief Sets streams to be returned by @c out() and @c err() methods.
     *
     * @param out Stream to use for regular output.
     * @param err Stream to use for error messages.
     */
    static void setStreams(std::ostream &out, std::ostream &err, pk<Tests>);

protected:
    /**
     * @brief Retrieves stream for writing normal output of a command.
     *
     * @returns The stream.
     */
    std::ostream & out();
    /**
     * @brief Retrieves stream for writing error output of a command.
     *
     * The stream is preconfigured to output command name, so don't duplicate
     * it.
     *
     * @returns The stream.
     */
    std::ostream & err();

private:
    /**
     * @brief Name of the command.
     */
    const std::string name;
    /**
     * @brief Short description.
     */
    const std::string descr;
    /**
     * @brief Longer description.
     */
    const std::string help;
};

/**
 * @brief Compares two commands by their names.
 *
 * @param l First command to compare.
 * @param r Second command to compare.
 *
 * @returns @c true if @p l is "less than" @p r, otherwise @c false is returned.
 */
inline bool
operator<(const Command &l, const Command &r)
{
    return l.getName() < r.getName();
}

#endif // DIT__COMMAND_HPP__