/* wf.c - list distinct words by frequency
 *
 * wf expects a filename to read words from as its single parameter, or reads 
 * from the standard input if no filename is given. Words occurences are
 * counted in a mapping collection (wordlist). This results in a mapping of
 * distinct words to frequencies, sorted alphabetically. By means of a 
 * callback iteration, the mappings are then transferred to another mapping 
 * collection (freqlist) where they are stored by frequency. This results in a
 * frequency sorted list which is then printed out. 
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>       /* for strdup, strpbrk */
#include <cprops/avl.h>   /* for binary tree */
#include <cprops/str.h>   /* for string functions */
#include <cprops/util.h>  /* for intdup, filter_string */

/* sort function for frequency list */
int freqcmp(int *a, int *b)
{
    return *b - *a;
}

/* callback for building frequency list from word list */
int add_freq(void *entry, void *tree)
{
    cp_avltree *freq = tree;
    cp_avlnode *node = entry;
    cp_avltree_insert(freq, node->value, node->key);

    return 0;
}

/* output callback */
int print_word_freq(void *entry, void *ordp)
{
    cp_avlnode *n = entry;
    int *count = n->key;
    cp_vector *res = n->value;
    int *ord = ordp;
    int i;

    for (i = 0; i < cp_vector_size(res); i++)
        printf("(%d) [%d] %s\n", *ord, *count, 
                (char *) cp_vector_element_at(res, i));
    (*ord)++;

    return 0;
}

#define PUNCT ".,!?;:\'\"~()\\/-[]<>"

int main(int argc, char *argv[])
{
    FILE *in = stdin;
    char buf[0x4000]; /* word length limited to 16K characters */
    cp_avltree *wordlist;
    cp_avltree *freqlist;
    int count = 0;
    int one = 1;
    int *wc;

    if (argc > 1) 
    {
        in = fopen(argv[1], "r");
        if (in == NULL)
        {
            fprintf(stderr, "can\'t open %s\n", argv[1]);
            exit(1);
        }
    }
    
    /* wordlist keys are distinct */
    wordlist = 
        cp_avltree_create_by_option(COLLECTION_MODE_NOSYNC | 
                                    COLLECTION_MODE_COPY | 
                                    COLLECTION_MODE_DEEP, 
                                    (cp_compare_fn) strcmp, 
                                    (cp_copy_fn) strdup, free, 
                                    (cp_copy_fn) intdup, free);
    
    while ((fscanf(in, "%s", buf)) != EOF)
    {
        filter_string(buf, PUNCT);
        to_lowercase(buf);
        wc = cp_avltree_get(wordlist, buf);
        if (wc) 
            (*wc)++;
        else
            cp_avltree_insert(wordlist, buf, &one);
        count++;
    }

    fclose(in);

    /* frequency list entry keys are not distinct */
    freqlist =     
        cp_avltree_create_by_option(COLLECTION_MODE_NOSYNC | 
                                    COLLECTION_MODE_MULTIPLE_VALUES,
                                    (cp_compare_fn) freqcmp, 
                                    NULL, NULL, NULL, NULL);
    
    cp_avltree_callback(wordlist, add_freq, freqlist);
    cp_avltree_callback(freqlist, print_word_freq, &one);
    printf("%d words, %d distinct entries\n", count, cp_avltree_count(wordlist));

    cp_avltree_destroy(freqlist);
    cp_avltree_destroy(wordlist);

    return 0;
}