/*
 * Copyright (C) 2020 Uniontech Technology Co., Ltd.
 *
 * Author:     xinbo wang <wangxinbo@uniontech.com>
 *
 * Maintainer: xinbo wang <wangxinbo@uniontech.com>
 *
 * 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 3 of the License, or
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "log.h"

#define MAX_CALLBACKS 32

typedef struct {
    log_LogFn fn;
    void *udata;
    int level;
} Callback;

static struct {
    void *udata;
    log_LockFn lock;
    int level;
    bool quiet;
    Callback callbacks[MAX_CALLBACKS];
} L;


static const char *level_strings[] = {
    "TRACE", "DEBUG", "INFO", "WARN", "ERROR", "FATAL"
};

#ifdef LOG_USE_COLOR
static const char *level_colors[] = {
    "\x1b[94m", "\x1b[36m", "\x1b[32m", "\x1b[33m", "\x1b[31m", "\x1b[35m"
};
#endif


static void stdout_callback(log_Event *ev) {
    char buf[16];
    buf[strftime(buf, sizeof(buf), "%H:%M:%S", ev->time)] = '\0';
#ifdef LOG_USE_COLOR
  fprintf(
      ev->udata, "%s %s%-5s\x1b[0m \x1b[90m%s:%d:\x1b[0m ",
      buf, level_colors[ev->level], level_strings[ev->level],
      ev->file, ev->line);
#else
    fprintf(
      (FILE*)ev->udata, "%s %-5s %s:%d: ",
      buf, level_strings[ev->level], ev->file, ev->line);
#endif
    vfprintf((FILE*)ev->udata, ev->fmt, ev->ap);
    fprintf((FILE*)ev->udata, "\n");
    fflush((FILE*)ev->udata);
}


static void file_callback(log_Event *ev) {
    char buf[64];
    buf[strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", ev->time)] = '\0';
    fprintf(
      (FILE*)ev->udata, "%s %-5s %s:%d: ",
      buf, level_strings[ev->level], ev->file, ev->line);
    vfprintf((FILE*)ev->udata, ev->fmt, ev->ap);
    fprintf((FILE*)ev->udata, "\n");
    fflush((FILE*)ev->udata);
}


static void lock(void)   {
    if (L.lock) { L.lock(true, L.udata); }
}


static void unlock(void) {
    if (L.lock) { L.lock(false, L.udata); }
}


const char* log_level_string(int level) {
    return level_strings[level];
}


void log_set_lock(log_LockFn fn, void *udata) {
    L.lock = fn;
    L.udata = udata;
}


void log_set_level(int level) {
    L.level = level;
}


void log_set_quiet(bool enable) {
    L.quiet = enable;
}


int log_add_callback(log_LogFn fn, void *udata, int level) {
    for (int i = 0; i < MAX_CALLBACKS; i++) {
      if (!L.callbacks[i].fn) {
        L.callbacks[i] = (Callback) { fn, udata, level };
        return 0;
      }
    }
    return -1;
}


int log_add_fp(FILE *fp, int level) {
    return log_add_callback(file_callback, fp, level);
}


static void init_event(log_Event *ev, void *udata) {
    if (!ev->time) {
      time_t t = time(NULL);
      ev->time = localtime(&t);
    }
    ev->udata = udata;
}


void log_log(int level, const char *file, int line, const char *fmt, ...) {
    log_Event ev = {
      .fmt   = fmt,
      .file  = file,
      .line  = line,
      .level = level,
    };

    lock();

    if (!L.quiet && level >= L.level) {
      init_event(&ev, stderr);
      va_start(ev.ap, fmt);
      stdout_callback(&ev);
      va_end(ev.ap);
    }

    for (int i = 0; i < MAX_CALLBACKS && L.callbacks[i].fn; i++) {
      Callback *cb = &L.callbacks[i];
      if (level >= cb->level) {
        init_event(&ev, cb->udata);
        va_start(ev.ap, fmt);
        cb->fn(&ev);
        va_end(ev.ap);
      }
    }

    unlock();
}
