/*********************************************************************************************************
 *  ------------------------------------------------------------------------------------------------------
 *  file description
 *  ------------------------------------------------------------------------------------------------------
 *         \file  vlog.c
 *         \unit  vlog
 *        \brief  This is a simple log module for C language
 *       \author  Lamdonn
 *      \version  v1.0.0
 *      \license  GPL-2.0
 *    \copyright  Copyright (C) 2023 Lamdonn.
 ********************************************************************************************************/
#include "vlog.h"
#include <stdio.h>

static char channel_table = VLOG_CHANNEL_0;                 /* Channel configuration, default only opens channel 0 */ 
static char vlog_buffer[VLOG_BUFFER_SIZE];                  /* vlog output buffer */ 
static vlog_func_t vlog_func = 0;                           /* Additional vlog callback function */ 
static FILE *vlog_file = 0;                                 /* Offline recorded files */ 

/**
 *  \brief output log information
 *  \param[in] channel: VLOG_CHANNEL_XXX, from 0 to 7
 *  \param[in] format: format string
 *  \param[in] ...: format parameters
 *  \return log string length
 */
int vlog(char channel, const char *format, ...)
{
    int len = 0;
    va_list args;

    /* Check channel effectiveness */
    if (channel & channel_table)
    {
        va_start(args, format);

        len = vsnprintf(vlog_buffer, sizeof(vlog_buffer), format, args);

        /* Output to default console */
        printf(vlog_buffer);

        /* Output to offline file */
        if (vlog_file) fwrite(vlog_buffer, sizeof(char), len, vlog_file);

        /* Output to callback function */
        if (vlog_func) vlog_func(vlog_buffer, len);

        va_end(args);
    }

    return len;
}

/**
 *  \brief set vlog channel configuration
 *  \param[in] channel: VLOG_CHANNEL_XXX, from 0 to 7, multiple channels can be selected through `|`
 *  \return none 
 */
void vlog_set_channel(char channel)
{
    channel_table = channel;
}

/**
 *  \brief get vlog channel configuration
 *  \return channel configuration 
 */
char vlog_get_channel(void)
{
    return channel_table;
}

/**
 *  \brief start vlog offline save, need to be used in pairs with vlog_stop_offline()
 *  \param[in] *filename: offline save file name
 *  \return 1 success or 0 fail 
 */
int vlog_start_offline(const char *filename)
{
    FILE *file;

    file = fopen(filename, "a+");
    if (!file) return 0;

    vlog_file = file;

    return 1;
}

/**
 *  \brief stop vlog offline save, need to be used in pairs with vlog_start_offline()
 *  \return none
 */
void vlog_stop_offline(void)
{
    if (vlog_file)
    {
        fclose(vlog_file);
        vlog_file = 0;
    }
}

/**
 *  \brief set additional vlog callback function
 *  \return none 
 */
void vlog_set_func(vlog_func_t func)
{
    vlog_func = func;
}