/**
 * @file lldir_linux.cpp
 * @brief Implementation of directory utilities for linux
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * 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
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "lldir_linux.h"
#include "llerror.h"
#include "llrand.h"
#include "llstring.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <glob.h>
#include <pwd.h>


static std::string getCurrentUserHome(char* fallback)
{
    const uid_t uid = getuid();
    struct passwd *pw;

    pw = getpwuid(uid);
    if ((pw != NULL) && (pw->pw_dir != NULL))
    {
        return pw->pw_dir;
    }

    LL_INFOS() << "Couldn't detect home directory from passwd - trying $HOME" << LL_ENDL;
    auto home_env = LLStringUtil::getoptenv("HOME");
    if (home_env)
    {
        return *home_env;
    }
    else
    {
        LL_WARNS() << "Couldn't detect home directory!  Falling back to " << fallback << LL_ENDL;
        return fallback;
    }
}


LLDir_Linux::LLDir_Linux()
{
    mDirDelimiter = "/";
    mCurrentDirIndex = -1;
    mCurrentDirCount = -1;
    mDirp = NULL;

    char tmp_str[LL_MAX_PATH];  /* Flawfinder: ignore */
    if (getcwd(tmp_str, LL_MAX_PATH) == NULL)
    {
        strcpy(tmp_str, "/tmp");
        LL_WARNS() << "Could not get current directory; changing to "
                << tmp_str << LL_ENDL;
        if (chdir(tmp_str) == -1)
        {
            LL_ERRS() << "Could not change directory to " << tmp_str << LL_ENDL;
        }
    }

    mExecutableFilename = "";
    mExecutablePathAndName = "";
#ifdef APP_LIBEXEC_DIR
    mExecutableDir = APP_LIBEXEC_DIR;
#else
    mExecutableDir = tmp_str;
#endif
    mWorkingDir = tmp_str;
#ifdef APP_RO_DATA_DIR
    mAppRODataDir = APP_RO_DATA_DIR;
#else
    mAppRODataDir = tmp_str;
#endif
    std::string::size_type build_dir_pos = mExecutableDir.rfind("/build-linux-");
    if (build_dir_pos != std::string::npos)
    {
        // ...we're in a dev checkout
        mSkinBaseDir = mExecutableDir.substr(0, build_dir_pos) + "/indra/newview/skins";
        LL_INFOS() << "Running in dev checkout with mSkinBaseDir "
         << mSkinBaseDir << LL_ENDL;
    }
    else
    {
        // ...normal installation running
        mSkinBaseDir = mAppRODataDir + mDirDelimiter + "skins";
    }

    mOSUserDir = getCurrentUserHome(tmp_str);
    mOSUserAppDir = "";
    mLindenUserDir = "";

    char path [32]; /* Flawfinder: ignore */

    // *NOTE: /proc/%d/exe doesn't work on FreeBSD. But that's ok,
    // because this is the linux implementation.

    snprintf (path, sizeof(path), "/proc/%d/exe", (int) getpid ());
    int rc = readlink (path, tmp_str, sizeof (tmp_str)-1);  /* Flawfinder: ignore */
    if ( (rc != -1) && (rc <= ((int) sizeof (tmp_str)-1)) )
    {
        tmp_str[rc] = '\0'; //readlink() doesn't 0-terminate the buffer
        mExecutablePathAndName = tmp_str;
        char *path_end;
        if ((path_end = strrchr(tmp_str,'/')))
        {
            *path_end = '\0';
            //mExecutableDir = tmp_str;
            mWorkingDir = tmp_str;
            mExecutableFilename = path_end+1;
        }
        else
        {
            mExecutableFilename = tmp_str;
        }
    }

#ifdef APP_PLUGIN_DIR
    mLLPluginDir = APP_PLUGIN_DIR;
#else
    mLLPluginDir = mExecutableDir + mDirDelimiter + "llplugin";
#endif

    // *TODO: don't use /tmp, use $HOME/.secondlife/tmp or something.
    mTempDir = "/tmp";
}

LLDir_Linux::~LLDir_Linux()
{
}

// Implementation


void LLDir_Linux::initAppDirs(const std::string &app_name,
                              const std::string& app_read_only_data_dir)
{
    // Allow override so test apps can read newview directory
    if (!app_read_only_data_dir.empty())
    {
        mAppRODataDir = app_read_only_data_dir;
        mSkinBaseDir = add(mAppRODataDir, "skins");
    }
    mAppName = app_name;

    std::string upper_app_name(app_name);
    LLStringUtil::toUpper(upper_app_name);

    auto app_home_env(LLStringUtil::getoptenv(upper_app_name + "_USER_DIR"));
    if (app_home_env)
    {
        // user has specified own userappdir i.e. $SECONDLIFE_USER_DIR
        mOSUserAppDir = *app_home_env;
    }
    else
    {
        // traditionally on unixoids, MyApp gets ~/.myapp dir for data
        mOSUserAppDir = mOSUserDir;
        mOSUserAppDir += "/";
        mOSUserAppDir += ".";
        std::string lower_app_name(app_name);
        LLStringUtil::toLower(lower_app_name);
        mOSUserAppDir += lower_app_name;
    }

    // create any directories we expect to write to.

    int res = LLFile::mkdir(mOSUserAppDir);
    if (res == -1)
    {
        LL_WARNS() << "Couldn't create app user dir " << mOSUserAppDir << LL_ENDL;
        LL_WARNS() << "Default to base dir" << mOSUserDir << LL_ENDL;
        mOSUserAppDir = mOSUserDir;
    }

    res = LLFile::mkdir(getExpandedFilename(LL_PATH_LOGS,""));
    if (res == -1)
    {
        LL_WARNS() << "Couldn't create LL_PATH_LOGS dir " << getExpandedFilename(LL_PATH_LOGS,"") << LL_ENDL;
    }

    res = LLFile::mkdir(getExpandedFilename(LL_PATH_USER_SETTINGS,""));
    if (res == -1)
    {
        LL_WARNS() << "Couldn't create LL_PATH_USER_SETTINGS dir " << getExpandedFilename(LL_PATH_USER_SETTINGS,"") << LL_ENDL;
    }

    res = LLFile::mkdir(getExpandedFilename(LL_PATH_CACHE,""));
    if (res == -1)
    {
        LL_WARNS() << "Couldn't create LL_PATH_CACHE dir " << getExpandedFilename(LL_PATH_CACHE,"") << LL_ENDL;
    }

    mCAFile = add(mAppRODataDir, "ca-bundle.crt");
}

U32 LLDir_Linux::countFilesInDir(const std::string &dirname, const std::string &mask)
{
    U32 file_count = 0;
    glob_t g;

    std::string tmp_str;
    tmp_str = dirname;
    tmp_str += mask;

    if(glob(tmp_str.c_str(), GLOB_NOSORT, NULL, &g) == 0)
    {
        file_count = g.gl_pathc;

        globfree(&g);
    }

    return (file_count);
}

std::string LLDir_Linux::getCurPath()
{
    char tmp_str[LL_MAX_PATH];  /* Flawfinder: ignore */
    if (getcwd(tmp_str, LL_MAX_PATH) == NULL)
    {
        LL_WARNS() << "Could not get current directory" << LL_ENDL;
        tmp_str[0] = '\0';
    }
    return tmp_str;
}


bool LLDir_Linux::fileExists(const std::string &filename) const
{
    struct stat stat_data;
    // Check the age of the file
    // Now, we see if the files we've gathered are recent...
    int res = stat(filename.c_str(), &stat_data);
    if (!res)
    {
        return true;
    }
    else
    {
        return false;
    }
}


/*virtual*/ std::string LLDir_Linux::getLLPluginLauncher()
{
    return gDirUtilp->getExecutableDir() + gDirUtilp->getDirDelimiter() +
        "SLPlugin";
}

/*virtual*/ std::string LLDir_Linux::getLLPluginFilename(std::string base_name)
{
    return gDirUtilp->getLLPluginDir() + gDirUtilp->getDirDelimiter() +
        "lib" + base_name + ".so";
}