/* Copyright (C) 2016-2019 J.F.Dockes
 *   This program 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 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 this program; if not, write to the
 *   Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "autoconfig.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "safefcntl.h"
#include "safeunistd.h"
#include "dirent.h"
#include "cstr.h"
#ifdef _WIN32
#include "safewindows.h"
#else
#include <sys/param.h>
#include <pwd.h>
#include <sys/file.h>
#endif
#include <math.h>
#include <errno.h>
#include <sys/types.h>
#include "safesysstat.h"

#include <mutex>
#include <map>
#include <unordered_map>
#include <list>

#include "rclutil.h"
#include "pathut.h"
#include "wipedir.h"
#include "transcode.h"
#include "md5ut.h"
#include "log.h"
#include "smallut.h"

using namespace std;

template <class T> void map_ss_cp_noshr(T s, T *d)
{
    for (const auto& ent : s) {
        d->insert(
            pair<string, string>(string(ent.first.begin(), ent.first.end()),
                                 string(ent.second.begin(), ent.second.end())));
    }
}
template void map_ss_cp_noshr<map<string, string> >(
    map<string, string> s, map<string, string>*d);
template void map_ss_cp_noshr<unordered_map<string, string> >(
    unordered_map<string,string> s, unordered_map<string,string>*d);

#ifdef _WIN32
static bool path_hasdrive(const string& s)
{
    if (s.size() >= 2 && isalpha(s[0]) && s[1] == ':') {
        return true;
    }
    return false;
}
static bool path_isdriveabs(const string& s)
{
    if (s.size() >= 3 && isalpha(s[0]) && s[1] == ':' && s[2] == '/') {
        return true;
    }
    return false;
}

#include <Shlwapi.h>
#pragma comment(lib, "shlwapi.lib")

string path_thisexecpath()
{
    wchar_t text[MAX_PATH];
    GetModuleFileNameW(NULL, text, MAX_PATH);
#ifdef NTDDI_WIN8_future
    PathCchRemoveFileSpec(text, MAX_PATH);
#else
    PathRemoveFileSpecW(text);
#endif
    string path;
    wchartoutf8(text, path);
    if (path.empty()) {
        path = "c:/";
    }

    return path;
}
string path_wingettempfilename(wchar_t *pref)
{
    // Use a subdirectory named "rcltmp" inside the windows temp
    // location.
    wchar_t dbuf[MAX_PATH + 1];
    GetTempPathW(MAX_PATH + 1, dbuf);
    string tdir;
    wchartoutf8(dbuf, tdir);
    tdir = path_cat(tdir, "rcltmp");;
    if (!path_exists(tdir)) {
        if (path_makepath(tdir, 0700)) {
            LOGSYSERR("path_wingettempfilename", "path_makepath", tdir);
        }
    }
    utf8towchar(tdir, dbuf, MAX_PATH);
    wchar_t buf[MAX_PATH + 1];
    GetTempFileNameW(dbuf, pref, 0, buf);
    // Windows will have created a temp file, we delete it.
    if (!DeleteFileW(buf)) {
        LOGSYSERR("path_wingettempfilename", "DeleteFileW", filename);
    } else {
        LOGDEB1("path_wingettempfilename: DeleteFile " << filename << " Ok\n");
    }
    string filename;
    wchartoutf8(buf, filename);
    path_slashize(filename);
    return filename;
}

#endif // _WIN32

// Check if path is either non-existing or an empty directory.
bool path_empty(const string& path)
{
    if (path_isdir(path)) {
        string reason;
        std::set<string> entries;
        if (!readdir(path, reason, entries) || entries.empty()) {
            return true;
        }
        return false;
    } else {
        return !path_exists(path);
    }
}

string path_defaultrecollconfsubdir()
{
#ifdef _WIN32
    return "Recoll";
#else
    return ".recoll";
#endif
}

// Location for sample config, filters, etc. (e.g. /usr/share/recoll/)
const string& path_pkgdatadir()
{
    static string datadir;
    if (datadir.empty()) {
#ifdef _WIN32
        datadir = path_cat(path_thisexecpath(), "Share");
#else
        const char *cdatadir = getenv("RECOLL_DATADIR");
        if (cdatadir == 0) {
            // If not in environment, use the compiled-in constant.
            datadir = RECOLL_DATADIR;
        } else {
            datadir = cdatadir;
        }
#endif
    }
    return datadir;
}

// Printable url: this is used to transcode from the system charset
// into either utf-8 if transcoding succeeds, or url-encoded
bool printableUrl(const string& fcharset, const string& in, string& out)
{
#ifdef _WIN32
    // On windows our paths are always utf-8
    out = in;
#else
    int ecnt = 0;
    if (!transcode(in, out, fcharset, "UTF-8", &ecnt) || ecnt) {
        out = url_encode(in, 7);
    }
#endif
    return true;
}

string url_gpathS(const string& url)
{
#ifdef _WIN32
    string u = url_gpath(url);
    string nu;
    if (path_hasdrive(u)) {
        nu.append(1, '/');
        nu.append(1, u[0]);
        if (path_isdriveabs(u)) {
            nu.append(u.substr(2));
        } else {
            // This should be an error really
            nu.append(1, '/');
            nu.append(u.substr(2));
        }
    }
    return nu;
#else
    return url_gpath(url);
#endif
}

const string& tmplocation()
{
    static string stmpdir;
    if (stmpdir.empty()) {
        const char *tmpdir = getenv("RECOLL_TMPDIR");
        if (tmpdir == 0) {
            tmpdir = getenv("TMPDIR");
        }
        if (tmpdir == 0) {
            tmpdir = getenv("TMP");
        }
        if (tmpdir == 0) {
            tmpdir = getenv("TEMP");
        }
        if (tmpdir == 0) {
#ifdef _WIN32
            wchar_t bufw[MAX_PATH + 1];
            GetTempPathW(MAX_PATH + 1, bufw);
            wchartoutf8(bufw, stmpdir);
#else
            stmpdir = "/tmp";
#endif
        } else {
            stmpdir = tmpdir;
        }
        stmpdir = path_canon(stmpdir);
    }

    return stmpdir;
}

bool maketmpdir(string& tdir, string& reason)
{
#ifndef _WIN32
    tdir = path_cat(tmplocation(), "rcltmpXXXXXX");

    char *cp = strdup(tdir.c_str());
    if (!cp) {
        reason = "maketmpdir: out of memory (for file name !)\n";
        tdir.erase();
        return false;
    }

    // There is a race condition between name computation and
    // mkdir. try to make sure that we at least don't shoot ourselves
    // in the foot
#if !defined(HAVE_MKDTEMP) || defined(_WIN32)
    static std::mutex mmutex;
    std::unique_lock<std::mutex> lock(mmutex);
#endif

    if (!
#ifdef HAVE_MKDTEMP
		mkdtemp(cp)
#else
		mktemp(cp)
#endif // HAVE_MKDTEMP
		) {
        free(cp);
        reason = "maketmpdir: mktemp failed for [" + tdir + "] : " +
			strerror(errno);
        tdir.erase();
        return false;
    }
    tdir = cp;
    free(cp);
#else // _WIN32
    // There is a race condition between name computation and
    // mkdir. try to make sure that we at least don't shoot ourselves
    // in the foot
    static std::mutex mmutex;
    std::unique_lock<std::mutex> lock(mmutex);
    static wchar_t tmpbasename[]{L"rcltmp"};
    tdir = path_wingettempfilename(tmpbasename);
#endif

    // At this point the directory does not exist yet except if we used
    // mkdtemp

#if !defined(HAVE_MKDTEMP) || defined(_WIN32)
    if (mkdir(tdir.c_str(), 0700) < 0) {
        reason = string("maketmpdir: mkdir ") + tdir + " failed";
        tdir.erase();
        return false;
    }
#endif

    return true;
}


class TempFile::Internal {
public:
    Internal(const std::string& suffix);
    ~Internal();
    friend class TempFile;
private:
    std::string m_filename;
    std::string m_reason;
    bool m_noremove{false};
};

TempFile::TempFile(const string& suffix)
    : m(new Internal(suffix))
{
}

TempFile::TempFile()
{
    m = std::shared_ptr<Internal>();
}

const char *TempFile::filename() const
{
    return m ? m->m_filename.c_str() : "";
}

const std::string& TempFile::getreason() const
{
    static string fatal{"fatal error"};
    return m ? m->m_reason : fatal;
}

void TempFile::setnoremove(bool onoff)
{
    if (m)
        m->m_noremove = onoff;
}

bool TempFile::ok() const
{
    return m ? !m->m_filename.empty() : false;
}

TempFile::Internal::Internal(const string& suffix)
{
    // Because we need a specific suffix, can't use mkstemp
    // well. There is a race condition between name computation and
    // file creation. try to make sure that we at least don't shoot
    // our own selves in the foot. maybe we'll use mkstemps one day.
    static std::mutex mmutex;
    std::unique_lock<std::mutex> lock(mmutex);

#ifndef _WIN32
    string filename = path_cat(tmplocation(), "rcltmpfXXXXXX");
    char *cp = strdup(filename.c_str());
    if (!cp) {
        m_reason = "Out of memory (for file name !)\n";
        return;
    }

    // Using mkstemp this way is awful (bot the suffix adding and
    // using mkstemp() instead of mktemp just to avoid the warnings)
    int fd;
    if ((fd = mkstemp(cp)) < 0) {
        free(cp);
        m_reason = "TempFileInternal: mkstemp failed\n";
        return;
    }
    close(fd);
    unlink(cp);
    filename = cp;
    free(cp);
#else
    static wchar_t tmpbasename[]{L"rcl"};
    string filename = path_wingettempfilename(tmpbasename);
#endif

    m_filename = filename + suffix;
    LOGDEB1("TempFile: filename: " << m_filename << endl);
    int fd1 = open(m_filename.c_str(), O_CREAT | O_EXCL, 0600);
    if (fd1 < 0) {
        m_reason = string("Open/create error. errno : ") +
            lltodecstr(errno) + " file name: " + m_filename;
        m_filename.erase();
    } else {
        close(fd1);
    }
}

#ifdef _WIN32
static list<string> remainingTempFileNames;
static std::mutex remTmpFNMutex;
#endif

TempFile::Internal::~Internal()
{
    if (!m_filename.empty() && !m_noremove) {
        LOGDEB1("TempFile:~: unlinking " << m_filename << endl);
        if (unlink(m_filename.c_str()) != 0) {
            LOGSYSERR("TempFile:~", "unlink", m_filename);
#ifdef _WIN32
            {
                std::unique_lock<std::mutex> lock(remTmpFNMutex);
                remainingTempFileNames.push_back(m_filename);
            }
#endif
        } else {
            LOGDEB1("TempFile:~: unlink " << m_filename << " Ok\n");
        }
    }
}

// On Windows we sometimes fail to remove temporary files because
// they are open. It's difficult to make sure this does not
// happen, so we add a cleaning pass after clearing the input
// handlers cache (which should kill subprocesses etc.)
void TempFile::tryRemoveAgain()
{
#ifdef _WIN32
	LOGDEB1("TempFile::tryRemoveAgain. List size: " <<
			remainingTempFileNames.size() << endl);
    std::unique_lock<std::mutex> lock(remTmpFNMutex);
    std::list<string>::iterator pos = remainingTempFileNames.begin();
    while (pos != remainingTempFileNames.end()) {
        if (unlink(pos->c_str()) != 0) {
            LOGSYSERR("TempFile::tryRemoveAgain", "unlink", *pos);
            pos++;
        } else {
            pos = remainingTempFileNames.erase(pos);
        }
    }
#endif
}

TempDir::TempDir()
{
    if (!maketmpdir(m_dirname, m_reason)) {
        m_dirname.erase();
        return;
    }
    LOGDEB("TempDir::TempDir: -> " << m_dirname << endl);
}

TempDir::~TempDir()
{
    if (!m_dirname.empty()) {
        LOGDEB("TempDir::~TempDir: erasing " << m_dirname << endl);
        (void)wipedir(m_dirname, true, true);
        m_dirname.erase();
    }
}

bool TempDir::wipe()
{
    if (m_dirname.empty()) {
        m_reason = "TempDir::wipe: no directory !\n";
        return false;
    }
    if (wipedir(m_dirname, false, true)) {
        m_reason = "TempDir::wipe: wipedir failed\n";
        return false;
    }
    return true;
}

// Freedesktop standard paths for cache directory (thumbnails are now in there)
static const string& xdgcachedir()
{
    static string xdgcache;
    if (xdgcache.empty()) {
        const char *cp = getenv("XDG_CACHE_HOME");
        if (cp == 0) {
            xdgcache = path_cat(path_home(), ".cache");
        } else {
            xdgcache = string(cp);
        }
    }
    return xdgcache;
}

static const string& thumbnailsdir()
{
    static string thumbnailsd;
    if (thumbnailsd.empty()) {
        thumbnailsd = path_cat(xdgcachedir(), "thumbnails");
        if (access(thumbnailsd.c_str(), 0) != 0) {
            thumbnailsd = path_cat(path_home(), ".thumbnails");
        }
    }
    return thumbnailsd;
}

// Place for 256x256 files
static const string thmbdirlarge = "large";
// 128x128
static const string thmbdirnormal = "normal";

static void thumbname(const string& url, string& name)
{
    string digest;
    string l_url = url_encode(url);
    MD5String(l_url, digest);
    MD5HexPrint(digest, name);
    name += ".png";
}

bool thumbPathForUrl(const string& url, int size, string& path)
{
    string name;
    thumbname(url, name);
    if (size <= 128) {
        path = path_cat(thumbnailsdir(), thmbdirnormal);
        path = path_cat(path, name);
        if (access(path.c_str(), R_OK) == 0) {
            return true;
        }
    }
    path = path_cat(thumbnailsdir(), thmbdirlarge);
    path = path_cat(path, name);
    if (access(path.c_str(), R_OK) == 0) {
        return true;
    }

    // File does not exist. Path corresponds to the large version at this point,
    // fix it if needed.
    if (size <= 128) {
        path = path_cat(path_home(), thmbdirnormal);
        path = path_cat(path, name);
    }
    return false;
}

void rclutil_init_mt()
{
    path_pkgdatadir();
    tmplocation();
    thumbnailsdir();
}