/*
 * (C) Copyright 2005- ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

#include "grib_api_internal.h"

/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = expression
   IMPLEMENTS = destroy
   IMPLEMENTS = native_type
   IMPLEMENTS = evaluate_long
   IMPLEMENTS = evaluate_double
   IMPLEMENTS = print
   IMPLEMENTS = add_dependency
   MEMBERS    = grib_expression *left
   MEMBERS = grib_expression *right
   END_CLASS_DEF

 */
/* START_CLASS_IMP */

/*

Don't edit anything between START_CLASS_IMP and END_CLASS_IMP
Instead edit values between START_CLASS_DEF and END_CLASS_DEF
or edit "expression.class" and rerun ./make_class.pl

*/

typedef const char* string; /* to keep make_class.pl happy */


static void init_class(grib_expression_class*);

static void destroy(grib_context*, grib_expression* e);

static void print(grib_context*, grib_expression*, grib_handle*);
static void add_dependency(grib_expression* e, grib_accessor* observer);

static int native_type(grib_expression*, grib_handle*);

static int evaluate_long(grib_expression*, grib_handle*, long*);
static int evaluate_double(grib_expression*, grib_handle*, double*);

typedef struct grib_expression_string_compare
{
    grib_expression base;
    /* Members defined in string_compare */
    grib_expression* left;
    grib_expression* right;
} grib_expression_string_compare;


static grib_expression_class _grib_expression_class_string_compare = {
    0,                                      /* super                     */
    "string_compare",                       /* name                      */
    sizeof(grib_expression_string_compare), /* size of instance          */
    0,                                      /* inited */
    &init_class,                            /* init_class */
    0,                                      /* constructor               */
    &destroy,                               /* destructor                */
    &print,
    &add_dependency,

    &native_type,
    0,

    &evaluate_long,
    &evaluate_double,
    0,
};

grib_expression_class* grib_expression_class_string_compare = &_grib_expression_class_string_compare;


static void init_class(grib_expression_class* c)
{
}
/* END_CLASS_IMP */

/* Note: A fast cut-down version of strcmp which does NOT return -1 */
/* 0 means input strings are equal and 1 means not equal */
GRIB_INLINE static int grib_inline_strcmp(const char* a, const char* b)
{
    if (*a != *b)
        return 1;
    while ((*a != 0 && *b != 0) && *(a) == *(b)) {
        a++;
        b++;
    }
    return (*a == 0 && *b == 0) ? 0 : 1;
}

static int evaluate_long(grib_expression* g, grib_handle* h, long* lres)
{
    int ret = 0;
    char b1[1024];
    size_t l1 = sizeof(b1);
    char b2[1024];
    size_t l2 = sizeof(b2);
    const char* v1 = NULL;
    const char* v2 = NULL;

    grib_expression_string_compare* e = (grib_expression_string_compare*)g;

    v1 = grib_expression_evaluate_string(h, e->left, b1, &l1, &ret);
    if (!v1 || ret) {
        *lres = 0;
        return ret;
    }

    v2 = grib_expression_evaluate_string(h, e->right, b2, &l2, &ret);
    if (!v2 || ret) {
        *lres = 0;
        return ret;
    }

    *lres = (grib_inline_strcmp(v1, v2) == 0);
    return GRIB_SUCCESS;
}

static int evaluate_double(grib_expression* g, grib_handle* h, double* dres)
{
    long n;
    int ret = evaluate_long(g, h, &n);
    *dres   = n;
    return ret;
}

static void print(grib_context* c, grib_expression* g, grib_handle* f)
{
    grib_expression_string_compare* e = (grib_expression_string_compare*)g;
    printf("string_compare(");
    grib_expression_print(c, e->left, f);
    printf(",");
    grib_expression_print(c, e->right, f);
    printf(")");
}

static void destroy(grib_context* c, grib_expression* g)
{
    grib_expression_string_compare* e = (grib_expression_string_compare*)g;
    grib_expression_free(c, e->left);
    grib_expression_free(c, e->right);
}

static void add_dependency(grib_expression* g, grib_accessor* observer)
{
    grib_expression_string_compare* e = (grib_expression_string_compare*)g;
    grib_dependency_observe_expression(observer, e->left);
    grib_dependency_observe_expression(observer, e->right);
}

grib_expression* new_string_compare_expression(grib_context* c,
                                               grib_expression* left, grib_expression* right)
{
    grib_expression_string_compare* e = (grib_expression_string_compare*)grib_context_malloc_clear_persistent(c, sizeof(grib_expression_string_compare));
    e->base.cclass                    = grib_expression_class_string_compare;
    e->left                           = left;
    e->right                          = right;
    return (grib_expression*)e;
}

static int native_type(grib_expression* g, grib_handle* h)
{
    return GRIB_TYPE_LONG;
}
