/*********************************************************************************
 *      Copyright:  (C) 2023 LingYun IoT System Studio.
 *                  All rights reserved.
 *
 *       Filename:  pack_json.c
 *    Description:  This file is JSON format string package and parser example
 *
 *        Version:  1.0.0(2023年07月10日)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2023年07月10日 17时57分00秒"
 *
 ********************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cjson/cJSON.h>

#define DEVSN_LEN     11

typedef struct data_s
{
        char        devsn[DEVSN_LEN+1];
        char        time[32];
        float       temp;
        float       rh;
} pack_t;

int pack_json(char *buf, int size, char *devsn, char *time, float temp, float rh);
int unpack_json(char *buf, int len, pack_t *pack);

int main (int argc, char **argv)
{
    char         buf[512];
    char        *devsn="ISK1023001";
    char        *time="2023-07-10 20:00:00";
    float        temp = 20.50;
    float        rh = 30.50;
    pack_t       data;
    int          rv;

    if( (rv=pack_json(buf, sizeof(buf), devsn, time, temp, rh)) < 0 )
    {
        printf("Package sample data message failed, rv=%d\n", rv);
        return rv;
    }

    if( (rv=unpack_json(buf, rv, &data)) < 0 )
    {
        printf("Parser sample data message failed, rv=%d\n", rv);
        return rv;
    }

    return 0;
}


int pack_json(char *buf, int size, char *devsn, char *time, float temp, float rh)
{
    if( !buf || size<=0 || !devsn || !time )
    {
        printf("\033[1;31m%s:%d %s() Invalid input arguments\033[0m\n", __FILE__, __LINE__, __func__);
        return -1;
    }

    memset(buf, 0, size);
    snprintf(buf, size, "{\"devsn\":\"%s\", \"time\":\"%s\", \"temperature\":%.2f, \"humidity\":%.2f}", devsn, time, temp, rh);

    printf("\033[1;32mPacket Message: %s\033[0m\n", buf);

    return strlen(buf);
}


int unpack_json(char *buf, int len, pack_t *pack)
{
    cJSON     *root = NULL;
    cJSON     *item;
    char      *value;
    int        bytes;
    int        rv = 0;

    if( !buf || len<=0 || !pack )
    {
        printf("\033[1;31m%s:%d %s() Invalid input arguments\033[0m\n", __FILE__, __LINE__, __func__);
        return -1;
    }

    printf("\033[1;33mParser Message: %s\033[0m\n", buf);

    root = cJSON_Parse(buf);
    if( !root )
    {
        printf("cJSON_Parse root failure: %s\n", cJSON_GetErrorPtr());
        return -2;
    }

    memset(pack, 0, sizeof(*pack));

    /*+--------------------------+
     *| Start parser SN segement |
     *+--------------------------+*/

    item = cJSON_GetObjectItem(root, "devsn");
    if( !item )
    {
        printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
        rv = -3;
        goto cleanup;
    }

    bytes = strlen(item->valuestring);
    bytes = bytes>sizeof(pack->devsn) ? sizeof(pack->devsn) : bytes;
    strncpy(pack->devsn, item->valuestring, bytes);
    printf("Found devsn      : %s\n", pack->devsn);


    /*+----------------------------+
     *| Start parser Time segement |
     *+----------------------------+*/

    item = cJSON_GetObjectItem(root, "time");
    if( !item )
    {
        printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
        rv = -4;
        goto cleanup;
    }

    bytes = strlen(item->valuestring);
    bytes = bytes>sizeof(pack->time) ? sizeof(pack->time) : bytes;
    strncpy(pack->time, item->valuestring, bytes);
    printf("Found time       : %s\n", pack->time);

    /*+--------------------------+
     *| Start parser temperature |
     *+--------------------------+*/

    item = cJSON_GetObjectItem(root, "temperature");
    if( !item )
    {
        printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
        rv = -5;
        goto cleanup;
    }

    pack->temp = item->valuedouble;
    printf("Found temperature: %.2f\n", pack->temp);

    /*+-----------------------+
     *| Start parser humidity |
     *+-----------------------+*/

    item = cJSON_GetObjectItem(root, "humidity");
    if( !item )
    {
        printf("cJSON_GetObjectItem() item failure: %s\n", cJSON_GetErrorPtr());
        rv = -6;
        goto cleanup;
    }

    pack->rh = item->valuedouble;
    printf("Found humidity   : %.2f\n", pack->rh);

cleanup:
    cJSON_Delete(root); /* must delete it, or it will result memory leak */
    return rv;
}