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

#define LEN 100

int getstr(char **s, FILE *f);
int maxl = LEN;

typedef struct a{
    char* time;
    char* hostname;
    char* app;
    char* message;
} info;

int main(){
    const char pattern[] = "[a-zA-Z0-9_-]+ [0-9][0-9] ([0-9][0-9]:[0-9][0-9]:[0-9][0-9]) ([a-zA-Z0-9_-]+) ([a-zA-Z0-9_-]+)(\\[[0-9]+\\])?: (.+)";
    regex_t expr_compiled;
    regcomp(&expr_compiled, pattern, REG_EXTENDED);
    regmatch_t groups[6];
    char* string = (char*)calloc(maxl, sizeof(char));
    info* l = (info*)calloc(1, sizeof(info));
    unsigned int len = 0;

    FILE *in;
    char name[] = "input.txt";
    in = fopen(name, "r");

    while(getstr(&string, in)){
        if (regexec(&expr_compiled, (const char *)string, 6, groups, 0) == 0){
            len++;
            l = (info*)realloc(l, sizeof(struct a) * (len+1));

            l[len].time = (char*)calloc(groups[1].rm_eo - groups[1].rm_so + 10, sizeof(char));
            strncpy(l[len].time, &(string[groups[1].rm_so]), groups[1].rm_eo - groups[1].rm_so);

            l[len].hostname = (char*)calloc(groups[2].rm_eo - groups[2].rm_so + 10, sizeof(char));
            strncpy(l[len].hostname, &(string[groups[2].rm_so]), groups[2].rm_eo - groups[2].rm_so);

            l[len].app = (char*)calloc(groups[3].rm_eo - groups[3].rm_so + 10, sizeof(char));
            strncpy(l[len].app, &(string[groups[3].rm_so]), groups[3].rm_eo - groups[3].rm_so);

            l[len].message = (char*)calloc(groups[5].rm_eo - groups[5].rm_so + 10, sizeof(char));
            strncpy(l[len].message, &(string[groups[5].rm_so]), groups[5].rm_eo - groups[5].rm_so);
        }
    }
    for(int i = 1; i <= len; i++){
        printf("Msg #%d\n", i);
        printf(" time:\t%s\n", l[i].time);
        printf(" host:\t%s\n", l[i].hostname);
        printf(" app:\t%s\n", l[i].app);
        printf(" msg:\t%s\n", l[i].message);
    }

    fclose(in);
    free(l);
    free(string);
    regfree(&expr_compiled);
    return 0;
}


int getstr(char **s, FILE *f)
{
    int i=0;
    char c;
    memset((*s), '\0', sizeof(char)*maxl);
    while(((c = fgetc(f)) != EOF) && (c != '\n')){
        (*s)[i++] = c;
        if(i>=maxl-1){
            maxl += LEN;
            (*s) = (char*)realloc((*s), sizeof(char) * maxl);
        }
    }
    return c != EOF;
}