/*
 * txtquery operations with ltree 
 * Teodor Sigaev <teodor@stack.net>
 */

#include "ltree.h"
#include <ctype.h>

PG_FUNCTION_INFO_V1(ltxtq_exec);
PG_FUNCTION_INFO_V1(ltxtq_rexec);

/*
 * check for boolean condition
 */
bool 
execute(ITEM * curitem, void *checkval, bool calcnot, bool (*chkcond) (void *checkval, ITEM * val)) {
	if (curitem->type == VAL)
		return (*chkcond) (checkval, curitem);
	else if (curitem->val == (int4) '!') {
		return (calcnot) ?
			((execute(curitem + 1, checkval, calcnot, chkcond)) ? false : true)
			: true;
	} else if (curitem->val == (int4) '&') {
		if (execute(curitem + curitem->left, checkval, calcnot, chkcond))   
			return execute(curitem + 1, checkval, calcnot, chkcond);
		else
			return false;
	} else   {						       /* |-operator */
		if (execute(curitem + curitem->left, checkval, calcnot, chkcond))
			return true;
		else
			return execute(curitem + 1, checkval, calcnot, chkcond);
	}
	return false;
}

typedef struct {
	ltree	*node;
	char       *operand;
} CHKVAL;

static bool
checkcondition_str(void* checkval, ITEM * val) {
	ltree_level *level = LTREE_FIRST( ((CHKVAL*)checkval)->node );
	int tlen = ((CHKVAL*)checkval)->node->numlevel;
	char *op = ((CHKVAL*)checkval)->operand + val->distance;
        int (*cmpptr)(const char *,const char *,size_t);

	cmpptr = ( val->flag & LVAR_INCASE ) ? strncasecmp : strncmp;
	while( tlen > 0 ) {
		if ( val->flag & LVAR_SUBLEXEM ) {
			if ( compare_subnode(level, op, val->length, cmpptr, (val->flag & LVAR_ANYEND) ) )
				return true;
		} else if ( 
			(
				val->length == level->len ||
				( level->len > val->length && (val->flag & LVAR_ANYEND) )
			) &&
				(*cmpptr)( op, level->name, val->length) == 0 )
			return true;

		tlen--;
		level = LEVEL_NEXT(level); 
	}

	return false;
}

Datum
ltxtq_exec(PG_FUNCTION_ARGS) {
	ltree     *val = PG_GETARG_LTREE(0);
	ltxtquery  *query = PG_GETARG_LTXTQUERY(1);
	CHKVAL	  chkval;
	bool	    result;

	chkval.node = val;
	chkval.operand = GETOPERAND(query);

	result = execute(
		GETQUERY(query),
		&chkval,
		true,
		checkcondition_str
	);

	PG_FREE_IF_COPY(val, 0);
	PG_FREE_IF_COPY(query, 1);
	PG_RETURN_BOOL(result);
}

Datum
ltxtq_rexec(PG_FUNCTION_ARGS) {
	PG_RETURN_DATUM( DirectFunctionCall2( ltxtq_exec,
		PG_GETARG_DATUM(1),
		PG_GETARG_DATUM(0)
	) );
}