#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>

//  THINGS WE SHOULD COUNT
typedef struct {
    int         bytes;
    int         lines;
    int         longest;
    int         words;
} COUNTS;

// ------------------------------------------------------------------------

void report_counts(COUNTS what, char *filename)
{
//  JUST DISPLAY THE REQUESTED COUNTS
    printf("%8d", what.lines);
    printf("%8d", what.words);
    printf("%8d", what.bytes);
    printf("%8d", what.longest);
//  ONLY DISPLAY THE FILENAME IF IT'S NOT NULL
    if(filename != NULL) {
        printf("\t\t%s", filename);
    }
    printf("\n");
}

void counter(FILE *fp, char *filename)
{
    COUNTS      this    = { 0, 0, 0, 0 };
    char        line[BUFSIZ];

//  FOREACH LINE READ FROM THE FILE-POINTER....
    while( fgets(line, sizeof line, fp) != NULL) {
        int     len             = 0;
        bool    inside_word     = false;
        char    *s              = line;

        ++this.lines;
//  UNTIL WE HAVE REACHED THE END OF THIS LINE....
        while(*s) {
            ++this.bytes;

//  FOR THE LONGEST LINE, TABS ARE EXPANDED TO A MULTIPLE OF 8 SPACES
            if(*s == '\t') {
                len     = (len+8) / 8 * 8;
            }
            else if(*s != '\n') {
                ++len;
            }

//  KEP TRACK OF WHETHER WE'RE INSIDE A WORD, OR NOT
            if(inside_word && isspace(*s)) {
                inside_word     = false;
            }
            else if(!inside_word && !isspace(*s)) {
                ++this.words;
                inside_word     = true;
            }
//  'WALK' ALONG THE LINE
            ++s;
        }

//  SEE IF WE'VE FOUND A NEW LONGEST LINE
        if(this.longest < len) {
            this.longest        = len;
        }
    }
    report_counts(this, filename);
}

// ------------------------------------------------------------------------

//  PROVIDE A 'USAGE' MESSAGE IF AN INVALID SWITCH PROVIDED
void usage(char *argv0)
{
    fprintf(stderr, "Usage: %s [-clLw] [file ...]\n", argv0);
    exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
//  ARGUMENTS PROVIDED, ITERATE OVER EACH TREATING IT AS A FILENAME
    for(int a=1 ; a<argc ; ++a) {

//  ATTEMPT TO OPEN EACH FILENAME
        FILE *fp = fopen(argv[a], "r");

//  REPORT AN ERROR IF OPENING FAILS
        if(fp == NULL) {
            fprintf(stderr, "Cannot open %s\n", argv[a]);
            exit(EXIT_FAILURE);
        }
//  FILE OPENED, COUNT ITS CONTENTS
        counter(fp, argv[a]);
        fclose(fp);
    }

    exit(EXIT_SUCCESS);
    return 0;
}