/**
 * @file llexternaleditor.h
 * @brief A convenient class to run external editor.
 *
 * $LicenseInfo:firstyear=2010&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLEXTERNALEDITOR_H
#define LL_LLEXTERNALEDITOR_H

#include "llprocess.h"

/**
 * Usage:
 *  LLExternalEditor ed;
 *  ed.setCommand("MY_EXTERNAL_EDITOR_VAR");
 *  ed.run("/path/to/file1");
 *  ed.run("/other/path/to/file2");
 */
class LLExternalEditor
{
    typedef std::vector<std::string> string_vec_t;

public:

    typedef enum e_error_code {
        EC_SUCCESS,             /// No error.
        EC_NOT_SPECIFIED,       /// Editor path not specified.
        EC_PARSE_ERROR,         /// Editor command parsing error.
        EC_BINARY_NOT_FOUND,    /// Could find the editor binary (missing or not quoted).
        EC_FAILED_TO_RUN,       /// Could not execute the editor binary.
    } EErrorCode;

    /**
     * Set editor command.
     *
     * @param env_var           Environment variable of the same purpose.
     * @param override          Optional override.
     *
     * First tries the override, then a predefined setting (sSetting),
     * then the environment variable.
     *
     * @return EC_SUCCESS if command is valid and refers to an existing executable,
     *         EC_NOT_SPECIFIED or EC_FAILED_TO_RUNan on error.
     *
     * @see sSetting
     */
    EErrorCode setCommand(const std::string& env_var, const std::string& override = LLStringUtil::null);

    /**
     * Run the editor with the given file.
     *
     * @param file_path File to edit.
     * @return EC_SUCCESS on success, error code on error.
     */
    EErrorCode run(const std::string& file_path);

    /**
     * Get a meaningful error message for the given status code.
     */
    static std::string getErrorMessage(EErrorCode code);

private:

    static std::string findCommand(
        const std::string& env_var,
        const std::string& override);

    static size_t tokenize(string_vec_t& tokens, const std::string& str);

    /**
     * Filename placeholder that gets replaced with an actual file name.
     */
    static const std::string sFilenameMarker;

    /**
     * Setting that can specify the editor command.
     */
    static const std::string sSetting;

    LLProcess::Params       mProcessParams;
};

#endif // LL_LLEXTERNALEDITOR_H