seconds_to_string_time.c

typedef struct 
{
    char* singular;
    char* plural;
    int duration;
} conversion_t;

const conversion_t CONVERSIONS[7] = {
    {"year", "years", 31536000},
    {"month", "months", 2628000},
    {"week", "weeks", 604800},
    {"day", "days", 86400},
    {"hour", "hours", 3600},
    {"minute", "minutes", 60},
    {"second", "seconds", 1}
};

const size_t TOTAL_CONVERSIONS = sizeof(CONVERSIONS) / sizeof(conversion_t);

char* secondsToStringTime(int seconds)
{
    int valid_results = 0;
    char* result[TOTAL_CONVERSIONS];

    for(int i = 0; i < TOTAL_CONVERSIONS; i++)
    {
        char* singular = CONVERSIONS[i].singular;
        char* plural = CONVERSIONS[i].plural;
        int duration = CONVERSIONS[i].duration;

        int count = 0;

        while(seconds - duration >= 0)
        {
            seconds -= duration;
            count++;
        }

        if(count == 0)
        {
            result[i] = NULL;
        }
        else
        {
            char* suffix = (count == 1 ? singular : plural);
            result[i] = (char*)malloc((count > 0 ? (int) log10 ((double) count) + 1 : count) + strlen(suffix) + 2);
            sprintf(result[i], "%d %s", count, suffix);

            valid_results++;
        }
    }

    if(valid_results > 1)
    {
        int buffSize = 0;
        for(unsigned int i = 0; i < TOTAL_CONVERSIONS; i++)
        {
            if(result[i]) 
            {
                buffSize += strlen(result[i]);
            }    
        }

        char* string = (char*)malloc(buffSize + ((TOTAL_CONVERSIONS - 2) * 2) + 1);
    
        for(unsigned int i = 0; i < TOTAL_CONVERSIONS - 1; i++)
        {
            if(result[i])
            {
                char* suffix = (i < TOTAL_CONVERSIONS - 2 ? ", " : "");
                sprintf(string, "%s%s", result[i], suffix);
            }
        }

        char* ret = (char*)malloc(strlen(string) + 5 + strlen(result[TOTAL_CONVERSIONS - 1]) + 1);
        sprintf(ret, "%s and %s", string, result[TOTAL_CONVERSIONS - 1]);

        for(unsigned int i = 0; i < TOTAL_CONVERSIONS; i++)
        {
            if(result[i])
            {
                free(result[i]);
            }
        }

        free(string);

        return ret;
    }
    else if(valid_results > 0)
    {
        return result[0];
    }
    else
    {
        char* ret = (char*)malloc(1);
        strcpy(ret, "");
        return ret;
    }
}