/*************************************************************************/
/* Copyright (c) 2004                                                    */
/* Daniel Sleator, David Temperley, and John Lafferty                    */
/* All rights reserved                                                   */
/*                                                                       */
/* Use of the link grammar parsing system is subject to the terms of the */
/* license set forth in the LICENSE file included with this software,    */
/* and also available at http://www.link.cs.cmu.edu/link/license.html    */
/* This license allows free redistribution and use in source and binary  */
/* forms, with or without modification, subject to certain conditions.   */
/*                                                                       */
/*************************************************************************/

#include <link-grammar/api.h>
#include "error.h"

/** 
 * Returns TRUE if the string contains an underbar character.
 */
int contains_underbar(const char * s)
{
	while(*s != '\0') {
		if (*s == '_') return TRUE;
		s++;
	}
	return FALSE;
}

/** 
 * Returns FALSE if it is not a correctly formed idiom string.
 * Such a string is correct if it:
 *   () contains no "."
 *   () non-empty strings separated by _
 */
static int is_idiom_string(const char * s)
{
	size_t len;
	const char * t;

	for (t = s; *t != '\0'; t++)
	{
		if (*t == '.') return FALSE;
	}

	len = strlen(s);
	if ((s[0] == '_') || (s[len-1] == '_'))
	{
		return FALSE;
	}

	for (t = s; *t != '\0'; t++)
	{
		if ((*t == '_') && (*(t+1) == '_')) return FALSE;
	}
	return TRUE;
}

/** 
 * return TRUE if the string s is a sequence of digits.
 */
static int is_number(const char *s)
{
	int nb;
	while(*s != '\0') {
		nb = is_utf8_digit(s);
		if (!nb) return FALSE;
		s += nb;
	}
	return TRUE;
}

/**
 * If the string contains a single ".", and ends in ".Ix" where
 * x is a number, return x.  Return -1 if not of this form.
 */
static int numberfy(const char * s)
{
	for (; (*s != '\0') && (*s != '.'); s++)
	  ;
	if (*s++ != '.') return -1;
	if (*s++ != 'I') return -1;
	if (!is_number(s)) return -1;
	return atoi(s);
}

/** 
 * Look for words that end in ".Ix" where x is a number.
 * Return the largest x found.
 */
static int max_postfix_found(Dict_node * d)
{
	int i, j;
	i = 0;
	while(d != NULL) {
		j = numberfy(d->string);
		if (j > i) i = j;
		d = d->right;
	}
	return i;
}

/**
 * build_idiom_word_name() -- return idiomized name of given string.
 *
 * Allocates string space and returns a pointer to it.
 * In this string is placed the idiomized name of the given string s.
 * This is the same as s, but with a postfix of ".Ix", where x is an
 * appropriate number.  x is the minimum number that distinguishes
 * this word from others in the dictionary.
 */
static const char * build_idiom_word_name(Dictionary dict, const char * s)
{
	char buff[2*MAX_WORD];
	char *x;
	int count;

	Dict_node *dn = dictionary_lookup_list(dict, s);
	count = max_postfix_found(dn)+1;
	free_lookup_list(dn);

	x = buff;
	while((*s != '\0') && (*s != '.'))
	{
		*x = *s;
		x++;
		s++;
	}
	sprintf(x, ".I%d",count);

	return string_set_add(buff, dict->string_set);
}

/**
 * Tear the idiom string apart.
 * Put the parts into a list of Dict_nodes (connected by their right pointers)
 * Sets the string fields of these Dict_nodes pointing to the
 * fragments of the string s.  Later these will be replaced by
 * correct names (with .Ix suffixes).
 * The list is reversed from the way they occur in the string.
 * A pointer to this list is returned.
 */
static Dict_node * make_idiom_Dict_nodes(Dictionary dict, const char * string)
{
	Dict_node * dn, * dn_new;
	char * t, *s, *p;
	int more, sz;
	dn = NULL;

	sz = strlen(string)+1;
	p = s = (char *) xalloc(sz);
	strcpy(s, string);

	while (*s != '\0') {
		t = s;
		while((*s != '\0') && (*s != '_')) s++;
		if (*s == '_') {
			more = TRUE;
			*s = '\0';
		} else {
			more = FALSE;
		}
		dn_new = (Dict_node *) xalloc(sizeof (Dict_node));
		dn_new->right = dn;
		dn = dn_new;
		dn->string = string_set_add(t, dict->string_set);
		dn->file = NULL;
		if (more) s++;
	}

	xfree(p, sz);
	return dn;
}

static char current_name[] = "AAAAAAAA";
#define CN_size (sizeof(current_name)-1)

static void increment_current_name(void)
{
	int i, carry;
	i = CN_size-1;
	carry = 1;
	while (carry == 1) {
		current_name[i]++;
		if (current_name[i] == 'Z'+1) {
			current_name[i] = 'A';
			carry = 1;
		} else {
			carry = 0;
		}
		i--;
	}
}

/**
 * Generate a new connector name obtained from the current_name.
 * allocate string space for it.
 * @return a pointer to connector name.
 */
static const char * generate_id_connector(Dictionary dict)
{
	char buff[2*MAX_WORD];
	unsigned int i;
	char * t;

	for (i=0; current_name[i] == 'A'; i++)
	  ;
	/* i is now the number of characters of current_name to skip */
	t = buff;

	/* All idiom connector names start with the two letters "ID" */
	*t++ = 'I';
	*t++ = 'D';
	for (; i < CN_size; i++ )
	{
		*t++ = current_name[i] ;
	}
	*t++ = '\0';
	return string_set_add(buff, dict->string_set);
}

/**
 * Takes as input a pointer to a Dict_node.
 * The string of this Dict_node is an idiom string.
 * This string is torn apart, and its components are inserted into the
 * dictionary as special idiom words (ending in .I*, where * is a number).
 * The expression of this Dict_node (its node field) has already been
 * read and constructed.  This will be used to construct the special idiom
 * expressions.
 * The given dict node is freed.  The string is also freed.
 */
void insert_idiom(Dictionary dict, Dict_node * dn)
{
	Exp * nc, * no, * n1;
	E_list *ell, *elr;
	const char * s;
	int s_length;
	Dict_node * dn_list, * xdn, * start_dn_list;

	no = dn->exp;
	s = dn->string;
	s_length = strlen(s);

	if (!is_idiom_string(s))
	{
		prt_error("Warning: Word \"%s\" on line %d "
		          "is not a correctly formed idiom string.\n"
		          "\tThis word will be ignored\n",
		          s, dict->line_number);

		xfree((char *)dn, sizeof (Dict_node));
		return;
	}

	dn_list = start_dn_list = make_idiom_Dict_nodes(dict, s);
	xfree((char *)dn, sizeof (Dict_node));

	if (dn_list->right == NULL) {
	  prt_error("Fatal Error: Idiom string with only one connector -- should have been caught");
		exit(1);
	}

	/* first make the nodes for the base word of the idiom (last word) */
	/* note that the last word of the idiom is first in our list */

	/* ----- this code just sets up the node fields of the dn_list ----*/
	nc = Exp_create(dict);
	nc->u.string = generate_id_connector(dict);
	nc->dir = '-';
	nc->multi = FALSE;
	nc->type = CONNECTOR_type;
	nc->cost = 0;

	n1 = Exp_create(dict);
	n1->u.l = ell = (E_list *) xalloc(sizeof(E_list));
	ell->next = elr = (E_list *) xalloc(sizeof(E_list));
	elr->next = NULL;
	ell->e = nc;
	elr->e = no;
	n1->type = AND_type;
	n1->cost = 0;

	dn_list->exp = n1;

	dn_list = dn_list->right;

	while(dn_list->right != NULL) {
		/* generate the expression for a middle idiom word */

		n1 = Exp_create(dict);
		n1->u.string = NULL;
		n1->type = AND_type;
		n1->cost = 0;
		n1->u.l = ell = (E_list *) xalloc(sizeof(E_list));
		ell->next = elr = (E_list *) xalloc(sizeof(E_list));
		elr->next = NULL;

		nc = Exp_create(dict);
		nc->u.string = generate_id_connector(dict);
		nc->dir = '+';
		nc->multi = FALSE;
		nc->type = CONNECTOR_type;
		nc->cost = 0;
		elr->e = nc;

		increment_current_name();

		nc = Exp_create(dict);
		nc->u.string = generate_id_connector(dict);
		nc->dir = '-';
		nc->multi = FALSE;
		nc->type = CONNECTOR_type;
		nc->cost = 0;

		ell->e = nc;

		dn_list->exp = n1;

		dn_list = dn_list->right;
	}
	/* now generate the last one */

	nc = Exp_create(dict);
	nc->u.string = generate_id_connector(dict);
	nc->dir = '+';
	nc->multi = FALSE;
	nc->type = CONNECTOR_type;
	nc->cost = 0;

	dn_list->exp = nc;

	increment_current_name();

	/* ---- end of the code alluded to above ---- */

	/* now its time to insert them into the dictionary */

	dn_list = start_dn_list;

	while (dn_list != NULL) {
		xdn = dn_list->right;
		dn_list->left = dn_list->right = NULL;
		dn_list->string = build_idiom_word_name(dict, dn_list->string);
		dict->root = insert_dict(dict, dict->root, dn_list);
		dict->num_entries++;
		dn_list = xdn;
	}
	/* xfree((char *)s, s_length+1); strings are handled by string_set */
}

/** 
 * returns TRUE if this is a word ending in ".Ix", where x is a number.
 */
int is_idiom_word(const char * s)
{
	return (numberfy(s) != -1) ;
}

#ifdef THIS_IS_NOT_USED
/*
  returns TRUE if the list of words contains only words that are
  idiom words.  This is useful, because under this condition you want
   to be able to insert the word anyway, as long as it doesn't match
   exactly.
*/
int only_idiom_words(Dict_node * dn)
{
	while(dn != NULL) {
		if (!is_idiom_word(dn->string)) return FALSE;
		dn = dn->right;
	}
	return TRUE;
}
#endif