/*
 * log.c
 * vim: expandtab:ts=4:sts=4:sw=4
 *
 * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
 * Copyright (C) 2018 - 2019 Michael Vetter <jubalh@idoru.org>
 *
 * This file is part of Profanity.
 *
 * Profanity 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.
 *
 * Profanity 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 Profanity.  If not, see <https://www.gnu.org/licenses/>.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link the code of portions of this program with the OpenSSL library under
 * certain conditions as described in each individual source file, and
 * distribute linked combinations including the two.
 *
 * You must obey the GNU General Public License in all respects for all of the
 * code used other than OpenSSL. If you modify file(s) with this exception, you
 * may extend this exception to your version of the file(s), but you are not
 * obligated to do so. If you do not wish to do so, delete this exception
 * statement from your version. If you delete this exception statement from all
 * source files in the program, then also delete it here.
 *
 */

#include "config.h"

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "glib.h"
#include "glib/gstdio.h"

#include "log.h"
#include "common.h"
#include "config/files.h"
#include "config/preferences.h"
#include "xmpp/xmpp.h"
#include "xmpp/muc.h"

#define PROF "prof"

static FILE* logp;
static gchar* mainlogfile = NULL;
static gboolean user_provided_log = FALSE;

static GTimeZone* tz;
static GDateTime* dt;
static log_level_t level_filter;

static GHashTable* logs;
static GHashTable* groupchat_logs;
static GDateTime* session_started;

static int stderr_inited;
static log_level_t stderr_level;
static int stderr_pipe[2];
static char* stderr_buf;
static GString* stderr_msg;

enum {
    STDERR_BUFSIZE = 4000,
    STDERR_RETRY_NR = 5,
};

struct dated_chat_log
{
    gchar* filename;
    GDateTime* date;
};

static gboolean _log_roll_needed(struct dated_chat_log* dated_log);
static struct dated_chat_log* _create_log(const char* const other, const char* const login);
static struct dated_chat_log* _create_groupchat_log(const char* const room, const char* const login);
static void _free_chat_log(struct dated_chat_log* dated_log);
static gboolean _key_equals(void* key1, void* key2);
static char* _get_log_filename(const char* const other, const char* const login, GDateTime* dt, gboolean is_room);
static void _rotate_log_file(void);
static char* _log_string_from_level(log_level_t level);
static void _chat_log_chat(const char* const login, const char* const other, const gchar* const msg,
                           chat_log_direction_t direction, GDateTime* timestamp, const char* const resourcepart);
static void _groupchat_log_chat(const gchar* const login, const gchar* const room, const gchar* const nick,
                                const gchar* const msg);

void
log_debug(const char* const msg, ...)
{
    va_list arg;
    va_start(arg, msg);
    GString* fmt_msg = g_string_new(NULL);
    g_string_vprintf(fmt_msg, msg, arg);
    log_msg(PROF_LEVEL_DEBUG, PROF, fmt_msg->str);
    g_string_free(fmt_msg, TRUE);
    va_end(arg);
}

void
log_info(const char* const msg, ...)
{
    va_list arg;
    va_start(arg, msg);
    GString* fmt_msg = g_string_new(NULL);
    g_string_vprintf(fmt_msg, msg, arg);
    log_msg(PROF_LEVEL_INFO, PROF, fmt_msg->str);
    g_string_free(fmt_msg, TRUE);
    va_end(arg);
}

void
log_warning(const char* const msg, ...)
{
    va_list arg;
    va_start(arg, msg);
    GString* fmt_msg = g_string_new(NULL);
    g_string_vprintf(fmt_msg, msg, arg);
    log_msg(PROF_LEVEL_WARN, PROF, fmt_msg->str);
    g_string_free(fmt_msg, TRUE);
    va_end(arg);
}

void
log_error(const char* const msg, ...)
{
    va_list arg;
    va_start(arg, msg);
    GString* fmt_msg = g_string_new(NULL);
    g_string_vprintf(fmt_msg, msg, arg);
    log_msg(PROF_LEVEL_ERROR, PROF, fmt_msg->str);
    g_string_free(fmt_msg, TRUE);
    va_end(arg);
}

void
log_init(log_level_t filter, char* log_file)
{
    level_filter = filter;
    tz = g_time_zone_new_local();

    if (log_file) {
        user_provided_log = TRUE;
    }

    gchar* lf = files_get_log_file(log_file);

    logp = fopen(lf, "a");
    g_chmod(lf, S_IRUSR | S_IWUSR);
    mainlogfile = g_strdup(lf);

    g_free(lf);
}

const char*
get_log_file_location(void)
{
    return mainlogfile;
}

log_level_t
log_get_filter(void)
{
    return level_filter;
}

void
log_close(void)
{
    g_free(mainlogfile);
    mainlogfile = NULL;
    g_time_zone_unref(tz);
    if (logp) {
        fclose(logp);
    }
}

void
log_msg(log_level_t level, const char* const area, const char* const msg)
{
    if (level >= level_filter && logp) {
        dt = g_date_time_new_now(tz);

        char* level_str = _log_string_from_level(level);

        gchar* date_fmt = g_date_time_format(dt, "%d/%m/%Y %H:%M:%S");

        fprintf(logp, "%s: %s: %s: %s\n", date_fmt, area, level_str, msg);
        g_date_time_unref(dt);

        fflush(logp);
        g_free(date_fmt);

        if (prefs_get_boolean(PREF_LOG_ROTATE) && !user_provided_log) {
            long result = ftell(logp);
            if (result != -1 && result >= prefs_get_max_log_size()) {
                _rotate_log_file();
            }
        }
    }
}

log_level_t
log_level_from_string(char* log_level)
{
    assert(log_level != NULL);
    if (strcmp(log_level, "DEBUG") == 0) {
        return PROF_LEVEL_DEBUG;
    } else if (strcmp(log_level, "INFO") == 0) {
        return PROF_LEVEL_INFO;
    } else if (strcmp(log_level, "WARN") == 0) {
        return PROF_LEVEL_WARN;
    } else if (strcmp(log_level, "ERROR") == 0) {
        return PROF_LEVEL_ERROR;
    } else { // default logging is warn
        return PROF_LEVEL_WARN;
    }
}

static void
_rotate_log_file(void)
{
    gchar* log_file = g_strdup(mainlogfile);
    size_t len = strlen(log_file);
    gchar* log_file_new = malloc(len + 4);

    // find an empty name. from .log -> log.01 -> log.99
    for (int i = 1; i < 100; i++) {
        g_sprintf(log_file_new, "%s.%02d", log_file, i);
        if (!g_file_test(log_file_new, G_FILE_TEST_EXISTS))
            break;
    }

    log_close();

    rename(log_file, log_file_new);

    log_init(log_get_filter(), NULL);

    free(log_file_new);
    free(log_file);
    log_info("Log has been rotated");
}

void
chat_log_init(void)
{
    session_started = g_date_time_new_now_local();
    log_info("Initialising chat logs");
    logs = g_hash_table_new_full(g_str_hash, (GEqualFunc)_key_equals, free,
                                 (GDestroyNotify)_free_chat_log);
}

void
groupchat_log_init(void)
{
    log_info("Initialising groupchat logs");
    groupchat_logs = g_hash_table_new_full(g_str_hash, (GEqualFunc)_key_equals, free,
                                           (GDestroyNotify)_free_chat_log);
}

void
chat_log_msg_out(const char* const barejid, const char* const msg, const char* const resource)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        _chat_log_chat(mybarejid, barejid, msg, PROF_OUT_LOG, NULL, resource);
        free(mybarejid);
    }
}

void
chat_log_otr_msg_out(const char* const barejid, const char* const msg, const char* const resource)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_otr_log = prefs_get_string(PREF_OTR_LOG);
        if (strcmp(pref_otr_log, "on") == 0) {
            _chat_log_chat(mybarejid, barejid, msg, PROF_OUT_LOG, NULL, resource);
        } else if (strcmp(pref_otr_log, "redact") == 0) {
            _chat_log_chat(mybarejid, barejid, "[redacted]", PROF_OUT_LOG, NULL, resource);
        }
        g_free(pref_otr_log);
        free(mybarejid);
    }
}

void
chat_log_pgp_msg_out(const char* const barejid, const char* const msg, const char* const resource)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_pgp_log = prefs_get_string(PREF_PGP_LOG);
        if (strcmp(pref_pgp_log, "on") == 0) {
            _chat_log_chat(mybarejid, barejid, msg, PROF_OUT_LOG, NULL, resource);
        } else if (strcmp(pref_pgp_log, "redact") == 0) {
            _chat_log_chat(mybarejid, barejid, "[redacted]", PROF_OUT_LOG, NULL, resource);
        }
        g_free(pref_pgp_log);
        free(mybarejid);
    }
}

void
chat_log_omemo_msg_out(const char* const barejid, const char* const msg, const char* const resource)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_omemo_log = prefs_get_string(PREF_OMEMO_LOG);
        if (strcmp(pref_omemo_log, "on") == 0) {
            _chat_log_chat(mybarejid, barejid, msg, PROF_OUT_LOG, NULL, resource);
        } else if (strcmp(pref_omemo_log, "redact") == 0) {
            _chat_log_chat(mybarejid, barejid, "[redacted]", PROF_OUT_LOG, NULL, resource);
        }
        g_free(pref_omemo_log);
        free(mybarejid);
    }
}

void
chat_log_otr_msg_in(ProfMessage* message)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_otr_log = prefs_get_string(PREF_OTR_LOG);
        if (message->enc == PROF_MSG_ENC_NONE || (strcmp(pref_otr_log, "on") == 0)) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, NULL);
            }
        } else if (strcmp(pref_otr_log, "redact") == 0) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, NULL);
            }
        }
        g_free(pref_otr_log);
        free(mybarejid);
    }
}

void
chat_log_pgp_msg_in(ProfMessage* message)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_pgp_log = prefs_get_string(PREF_PGP_LOG);
        if (strcmp(pref_pgp_log, "on") == 0) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, NULL);
            }
        } else if (strcmp(pref_pgp_log, "redact") == 0) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, NULL);
            }
        }
        g_free(pref_pgp_log);
        free(mybarejid);
    }
}

void
chat_log_omemo_msg_in(ProfMessage* message)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_omemo_log = prefs_get_string(PREF_OMEMO_LOG);
        if (strcmp(pref_omemo_log, "on") == 0) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, NULL);
            }
        } else if (strcmp(pref_omemo_log, "redact") == 0) {
            if (message->type == PROF_MSG_TYPE_MUCPM) {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            } else {
                _chat_log_chat(mybarejid, message->from_jid->barejid, "[redacted]", PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
            }
        }
        g_free(pref_omemo_log);
        free(mybarejid);
    }
}

void
chat_log_msg_in(ProfMessage* message)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();

        if (message->type == PROF_MSG_TYPE_MUCPM) {
            _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, message->from_jid->resourcepart);
        } else {
            _chat_log_chat(mybarejid, message->from_jid->barejid, message->plain, PROF_IN_LOG, message->timestamp, NULL);
        }

        free(mybarejid);
    }
}

static void
_chat_log_chat(const char* const login, const char* const other, const char* const msg,
               chat_log_direction_t direction, GDateTime* timestamp, const char* const resourcepart)
{
    char* other_name;
    GString* other_str = NULL;

    if (resourcepart) {
        other_str = g_string_new(other);
        g_string_append(other_str, "_");
        g_string_append(other_str, resourcepart);

        other_name = other_str->str;
    } else {
        other_name = (char*)other;
    }

    struct dated_chat_log* dated_log = g_hash_table_lookup(logs, other_name);

    // no log for user
    if (dated_log == NULL) {
        dated_log = _create_log(other_name, login);
        g_hash_table_insert(logs, strdup(other_name), dated_log);

        // log entry exists but file removed
    } else if (!g_file_test(dated_log->filename, G_FILE_TEST_EXISTS)) {
        dated_log = _create_log(other_name, login);
        g_hash_table_replace(logs, strdup(other_name), dated_log);

        // log file needs rolling
    } else if (_log_roll_needed(dated_log)) {
        dated_log = _create_log(other_name, login);
        g_hash_table_replace(logs, strdup(other_name), dated_log);
    }

    if (resourcepart) {
        g_string_free(other_str, TRUE);
    }

    if (timestamp == NULL) {
        timestamp = g_date_time_new_now_local();
    } else {
        g_date_time_ref(timestamp);
    }

    gchar* date_fmt = g_date_time_format(timestamp, "%H:%M:%S");
    FILE* chatlogp = fopen(dated_log->filename, "a");
    g_chmod(dated_log->filename, S_IRUSR | S_IWUSR);
    if (chatlogp) {
        if (direction == PROF_IN_LOG) {
            if (strncmp(msg, "/me ", 4) == 0) {
                if (resourcepart) {
                    fprintf(chatlogp, "%s - *%s %s\n", date_fmt, resourcepart, msg + 4);
                } else {
                    fprintf(chatlogp, "%s - *%s %s\n", date_fmt, other, msg + 4);
                }
            } else {
                if (resourcepart) {
                    fprintf(chatlogp, "%s - %s: %s\n", date_fmt, resourcepart, msg);
                } else {
                    fprintf(chatlogp, "%s - %s: %s\n", date_fmt, other, msg);
                }
            }
        } else {
            if (strncmp(msg, "/me ", 4) == 0) {
                fprintf(chatlogp, "%s - *me %s\n", date_fmt, msg + 4);
            } else {
                fprintf(chatlogp, "%s - me: %s\n", date_fmt, msg);
            }
        }
        fflush(chatlogp);
        int result = fclose(chatlogp);
        if (result == EOF) {
            log_error("Error closing file %s, errno = %d", dated_log->filename, errno);
        }
    }

    g_free(date_fmt);
    g_date_time_unref(timestamp);
}

void
groupchat_log_msg_out(const gchar* const room, const gchar* const msg)
{
    if (prefs_get_boolean(PREF_GRLOG)) {
        char* mybarejid = connection_get_barejid();
        char* mynick = muc_nick(room);
        _groupchat_log_chat(mybarejid, room, mynick, msg);
        free(mybarejid);
    }
}

void
groupchat_log_msg_in(const gchar* const room, const gchar* const nick, const gchar* const msg)
{
    if (prefs_get_boolean(PREF_GRLOG)) {
        char* mybarejid = connection_get_barejid();
        _groupchat_log_chat(mybarejid, room, nick, msg);
        free(mybarejid);
    }
}

void
groupchat_log_omemo_msg_out(const gchar* const room, const gchar* const msg)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_omemo_log = prefs_get_string(PREF_OMEMO_LOG);
        char* mynick = muc_nick(room);

        if (strcmp(pref_omemo_log, "on") == 0) {
            _groupchat_log_chat(mybarejid, room, mynick, msg);
        } else if (strcmp(pref_omemo_log, "redact") == 0) {
            _groupchat_log_chat(mybarejid, room, mynick, "[redacted]");
        }

        g_free(pref_omemo_log);
        free(mybarejid);
    }
}

void
groupchat_log_omemo_msg_in(const gchar* const room, const gchar* const nick, const gchar* const msg)
{
    if (prefs_get_boolean(PREF_CHLOG)) {
        char* mybarejid = connection_get_barejid();
        char* pref_omemo_log = prefs_get_string(PREF_OMEMO_LOG);

        if (strcmp(pref_omemo_log, "on") == 0) {
            _groupchat_log_chat(mybarejid, room, nick, msg);
        } else if (strcmp(pref_omemo_log, "redact") == 0) {
            _groupchat_log_chat(mybarejid, room, nick, "[redacted]");
        }

        g_free(pref_omemo_log);
        free(mybarejid);
    }
}

void
_groupchat_log_chat(const gchar* const login, const gchar* const room, const gchar* const nick,
                    const gchar* const msg)
{
    struct dated_chat_log* dated_log = g_hash_table_lookup(groupchat_logs, room);

    // no log for room
    if (dated_log == NULL) {
        dated_log = _create_groupchat_log(room, login);
        g_hash_table_insert(groupchat_logs, strdup(room), dated_log);

        // log exists but needs rolling
    } else if (_log_roll_needed(dated_log)) {
        dated_log = _create_groupchat_log(room, login);
        g_hash_table_replace(logs, strdup(room), dated_log);
    }

    GDateTime* dt_tmp = g_date_time_new_now_local();

    gchar* date_fmt = g_date_time_format(dt_tmp, "%H:%M:%S");

    FILE* grpchatlogp = fopen(dated_log->filename, "a");
    g_chmod(dated_log->filename, S_IRUSR | S_IWUSR);
    if (grpchatlogp) {
        if (strncmp(msg, "/me ", 4) == 0) {
            fprintf(grpchatlogp, "%s - *%s %s\n", date_fmt, nick, msg + 4);
        } else {
            fprintf(grpchatlogp, "%s - %s: %s\n", date_fmt, nick, msg);
        }

        fflush(grpchatlogp);
        int result = fclose(grpchatlogp);
        if (result == EOF) {
            log_error("Error closing file %s, errno = %d", dated_log->filename, errno);
        }
    }

    g_free(date_fmt);
    g_date_time_unref(dt_tmp);
}

void
chat_log_close(void)
{
    g_hash_table_destroy(logs);
    g_hash_table_destroy(groupchat_logs);
    g_date_time_unref(session_started);
}

static struct dated_chat_log*
_create_log(const char* const other, const char* const login)
{
    GDateTime* now = g_date_time_new_now_local();
    char* filename = _get_log_filename(other, login, now, FALSE);

    struct dated_chat_log* new_log = malloc(sizeof(struct dated_chat_log));
    new_log->filename = strdup(filename);
    new_log->date = now;

    free(filename);

    return new_log;
}

static struct dated_chat_log*
_create_groupchat_log(const char* const room, const char* const login)
{
    GDateTime* now = g_date_time_new_now_local();
    char* filename = _get_log_filename(room, login, now, TRUE);

    struct dated_chat_log* new_log = malloc(sizeof(struct dated_chat_log));
    new_log->filename = strdup(filename);
    new_log->date = now;

    free(filename);

    return new_log;
}

static gboolean
_log_roll_needed(struct dated_chat_log* dated_log)
{
    gboolean result = FALSE;
    GDateTime* now = g_date_time_new_now_local();
    if (g_date_time_get_day_of_year(dated_log->date) != g_date_time_get_day_of_year(now)) {
        result = TRUE;
    }
    g_date_time_unref(now);

    return result;
}

static void
_free_chat_log(struct dated_chat_log* dated_log)
{
    if (dated_log) {
        if (dated_log->filename) {
            g_free(dated_log->filename);
            dated_log->filename = NULL;
        }
        if (dated_log->date) {
            g_date_time_unref(dated_log->date);
            dated_log->date = NULL;
        }
        free(dated_log);
    }
}

static gboolean
_key_equals(void* key1, void* key2)
{
    gchar* str1 = (gchar*)key1;
    gchar* str2 = (gchar*)key2;

    return (g_strcmp0(str1, str2) == 0);
}

static char*
_get_log_filename(const char* const other, const char* const login, GDateTime* dt, gboolean is_room)
{
    gchar* chatlogs_dir = files_file_in_account_data_path(DIR_CHATLOGS, login, is_room ? "rooms" : NULL);
    gchar* logfile_name = g_date_time_format(dt, "%Y_%m_%d.log");
    gchar* logfile_path = files_file_in_account_data_path(chatlogs_dir, other, logfile_name);

    g_free(logfile_name);
    g_free(chatlogs_dir);

    return logfile_path;
}

static char*
_log_string_from_level(log_level_t level)
{
    switch (level) {
    case PROF_LEVEL_ERROR:
        return "ERR";
    case PROF_LEVEL_WARN:
        return "WRN";
    case PROF_LEVEL_INFO:
        return "INF";
    case PROF_LEVEL_DEBUG:
        return "DBG";
    default:
        return "LOG";
    }
}

void
log_stderr_handler(void)
{
    GString* const s = stderr_msg;
    char* const buf = stderr_buf;
    ssize_t size;
    int retry = 0;

    if (!stderr_inited)
        return;

    do {
        size = read(stderr_pipe[0], buf, STDERR_BUFSIZE);
        if (size == -1 && errno == EINTR && retry++ < STDERR_RETRY_NR)
            continue;
        if (size <= 0 || retry++ >= STDERR_RETRY_NR)
            break;

        for (int i = 0; i < size; ++i) {
            if (buf[i] == '\n') {
                log_msg(stderr_level, "stderr", s->str);
                g_string_assign(s, "");
            } else
                g_string_append_c(s, buf[i]);
        }
    } while (1);

    if (s->len > 0 && s->str[0] != '\0') {
        log_msg(stderr_level, "stderr", s->str);
        g_string_assign(s, "");
    }
}

static int
log_stderr_nonblock_set(int fd)
{
    int rc;

    rc = fcntl(fd, F_GETFL);
    if (rc >= 0)
        rc = fcntl(fd, F_SETFL, rc | O_NONBLOCK);

    return rc;
}

void
log_stderr_init(log_level_t level)
{
    int rc;

    rc = pipe(stderr_pipe);
    if (rc != 0)
        goto err;

    close(STDERR_FILENO);
    rc = dup2(stderr_pipe[1], STDERR_FILENO);
    if (rc < 0)
        goto err_close;

    rc = log_stderr_nonblock_set(stderr_pipe[0])
             ?: log_stderr_nonblock_set(stderr_pipe[1]);
    if (rc != 0)
        goto err_close;

    stderr_buf = malloc(STDERR_BUFSIZE);
    stderr_msg = g_string_sized_new(STDERR_BUFSIZE);
    stderr_level = level;
    stderr_inited = 1;

    if (stderr_buf == NULL || stderr_msg == NULL) {
        errno = ENOMEM;
        goto err_free;
    }
    return;

err_free:
    if (stderr_msg != NULL)
        g_string_free(stderr_msg, TRUE);
    free(stderr_buf);
err_close:
    close(stderr_pipe[0]);
    close(stderr_pipe[1]);
err:
    stderr_inited = 0;
    log_error("Unable to init stderr log handler: %s", strerror(errno));
}

void
log_stderr_close(void)
{
    if (!stderr_inited)
        return;

    /* handle remaining logs before close */
    log_stderr_handler();
    stderr_inited = 0;
    free(stderr_buf);
    g_string_free(stderr_msg, TRUE);
    close(stderr_pipe[0]);
    close(stderr_pipe[1]);
}