#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <ctype.h>

#define DICTIONARY      "/usr/share/dict/words"
#define LONGEST_WORD    100

void trim_line(char line[])
{
    int i = 0;

//  LOOP UNTIL WE REACH THE END OF line
    while(line[i] != '\0') {

//  CHECK FOR CARRIAGE-RETURN OR NEWLINE
        if( line[i] == '\r' || line[i] == '\n' ) {
            line[i] = '\0'; // overwrite with nul-byte
            break;          // leave the loop early
        }
        i = i+1;            // iterate through character array
    }
}

//  ENSURE THAT A WORD CONTAINS ONLY LOWERCASE CHARACTERS
bool valid_word(char word[])
{
    int i       = 0;

//  IF NOT A LOWERCASE CHARACTER, THE FUNCTION RETURNS false
    while(word[i] != '\0') {
        if( ! islower( word[i] )) {
            return false;
        }
        i = i+1;
    }
//  WE'VE REACHED THE END OF THE WORD - IT'S ALL LOWERCASE
    return true;
}

//  CALCULATE THE SCRABBLE VALUE OF ANY WORD
int calc_value(char word[])
{
//  AN ARRAY TO PROVIDE THE VALUE OF EACH LETTER, FROM 'a' TO 'z'  
    int values[] = {  1, 3, 3, 2, 1, 4, 2, 4, 1, 8, 5, 1, 3, 1,  
                      1, 3, 10, 1, 1, 1, 1, 4, 4, 8, 4, 10 };
    int total    = 0;
    int i        = 0;

//  TRAVERSE THE WORD DETERMINING THE VALUE OF EACH LETTER
    while(word[i] != '\0') {
        total   = total + values[ word[i] - 'a' ];
        i = i+1;
    }
    return total;
}

//  FIND THE WORD WITH THE BEST VALUE
void findbest( char filename[] )
{
    FILE        *fp  = fopen(filename, "r");

//  ENSURE THAT WE CAN OPEN (WITH READ-ACCESS) THE FILE
    if(fp != NULL) {
        char    bestword[LONGEST_WORD];
        int     bestvalue       = 0;
        char    thisword[LONGEST_WORD];
        int     thisvalue       = 0;

//  READ EACH LINE OF THE FILE
        while( fgets(thisword, sizeof thisword, fp) ) {
//  REPLACE THE NEWLINE CHARACTER WITH A NUL-BYTE
            trim_line( thisword );

//  ENSURE THAT THIS WORD IS VALID (previously defined)
            if( valid_word(thisword) ) {
                thisvalue = calc_value( thisword );

//  IS THIS WORD BETTER THAN THE PREVIOUSLY BEST?
                if(bestvalue < thisvalue) {
                    bestvalue   = thisvalue;    // save current details
                    strcpy(bestword, thisword);
                }
            }
        }
        fclose(fp);
        printf("best word is %s = %d\n", bestword, bestvalue);
    }
}

int main(int argc, char *argv[])
{
    findbest( DICTIONARY );
    return 0;
}