/*
 * This file is part of the EasyLogger Library.
 *
 * Copyright (c) 2015-2019, Qintl, <qintl_linux@163.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * 'Software'), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * Function: Save log to file.
 * Created on: 2019-01-05
 */

 #define LOG_TAG    "elog.file"

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>

#include "elog_file.h"

/* initialize OK flag */
static bool init_ok = false;
static FILE *fp = NULL;
static ElogFileCfg local_cfg;

ElogErrCode elog_file_init(void)
{
    ElogErrCode result = ELOG_NO_ERR;
    ElogFileCfg cfg;

    if (init_ok)
        goto __exit;

    elog_file_port_init();

    cfg.name = ELOG_FILE_NAME;
    cfg.max_size = ELOG_FILE_MAX_SIZE;
    cfg.max_rotate = ELOG_FILE_MAX_ROTATE;

    elog_file_config(&cfg);

    init_ok = true;
__exit:
    return result;
}

/*
 * rotate the log file xxx.log.n-1 => xxx.log.n, and xxx.log => xxx.log.0
 */
static bool elog_file_rotate(void)
{
#define SUFFIX_LEN                     10
    /* mv xxx.log.n-1 => xxx.log.n, and xxx.log => xxx.log.0 */
    int n, err = 0;
    char oldpath[256], newpath[256];
    size_t base = strlen(local_cfg.name);
    bool result = true;
    FILE *tmp_fp;

    memcpy(oldpath, local_cfg.name, base);
    memcpy(newpath, local_cfg.name, base);

    fclose(fp);

    for (n = local_cfg.max_rotate - 1; n >= 0; --n) {
        snprintf(oldpath + base, SUFFIX_LEN, n ? ".%d" : "", n - 1);
        snprintf(newpath + base, SUFFIX_LEN, ".%d", n);
        /* remove the old file */
        if ((tmp_fp = fopen(newpath , "r")) != NULL) {
            fclose(tmp_fp);
            remove(newpath);
        }
        /* change the new log file to old file name */
        if ((tmp_fp = fopen(oldpath , "r")) != NULL) {
            fclose(tmp_fp);
            err = rename(oldpath, newpath);
        }

        if (err < 0) {
            result = false;
            goto __exit;
        }
    }

__exit:
    /* reopen the file */
    fp = fopen(local_cfg.name, "a+");

    return result;
}


void elog_file_write(const char *log, size_t size)
{
    size_t file_size = 0;

    ELOG_ASSERT(init_ok);
    ELOG_ASSERT(log);

    elog_file_port_lock();

    fseek(fp, 0L, SEEK_END);
    file_size = ftell(fp);

    if (unlikely(file_size > local_cfg.max_size)) {
#if ELOG_FILE_MAX_ROTATE > 0
        if (!elog_file_rotate()) {
            goto __exit;
        }
#else
        goto __exit;
#endif
    }

    fwrite(log, size, 1, fp);

#ifdef ELOG_FILE_FLUSH_CACHE_ENABLE
    fflush(fp);
#endif

__exit:
    elog_file_port_unlock();
}

void elog_file_deinit(void)
{
    ELOG_ASSERT(init_ok);

    ElogFileCfg cfg = {NULL, 0, 0};

    elog_file_config(&cfg);

    elog_file_port_deinit();

    init_ok = false;
}

void elog_file_config(ElogFileCfg *cfg)
{
    elog_file_port_lock();

    if (fp) {
        fclose(fp);
        fp = NULL;
    }

    if (cfg != NULL) {
        local_cfg.name = cfg->name;
        local_cfg.max_size = cfg->max_size;
        local_cfg.max_rotate = cfg->max_rotate;

        if (local_cfg.name != NULL && strlen(local_cfg.name) > 0)
            fp = fopen(local_cfg.name, "a+");
    }

    elog_file_port_unlock();
}