/*
 * (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 = native_type
   IMPLEMENTS = destroy
   IMPLEMENTS = evaluate_string
   IMPLEMENTS = print
   IMPLEMENTS = add_dependency
   MEMBERS    = char* value
   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 string evaluate_string(grib_expression*, grib_handle*, char*, size_t*, int*);

typedef struct grib_expression_sub_string
{
    grib_expression base;
    /* Members defined in sub_string */
    char* value;
} grib_expression_sub_string;


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

    &native_type,
    0,

    0,
    0,
    &evaluate_string,
};

grib_expression_class* grib_expression_class_sub_string = &_grib_expression_class_sub_string;


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

static const char* evaluate_string(grib_expression* g, grib_handle* h, char* buf, size_t* size, int* err)
{
    grib_expression_sub_string* e = (grib_expression_sub_string*)g;
    *err                          = 0;
    return e->value;
}

static void print(grib_context* c, grib_expression* g, grib_handle* f)
{
    grib_expression_sub_string* e = (grib_expression_sub_string*)g;
    printf("string('%s')", e->value);
}

static void destroy(grib_context* c, grib_expression* g)
{
    grib_expression_sub_string* e = (grib_expression_sub_string*)g;
    grib_context_free_persistent(c, e->value);
}

static void add_dependency(grib_expression* g, grib_accessor* observer)
{
    /* grib_expression_sub_string* e = (grib_expression_sub_string*)g; */
}

grib_expression* new_sub_string_expression(grib_context* c, const char* value, size_t start, size_t length)
{
    char v[1024] = {0,};
    grib_expression_sub_string* e = (grib_expression_sub_string*)grib_context_malloc_clear_persistent(c, sizeof(grib_expression_sub_string));
    const size_t slen             = strlen(value);
    /* 	if (start<0) start+=strlen(value);  */

    if (length == 0) {
        grib_context_log(c, GRIB_LOG_ERROR, "Invalid substring: length must be > 0");
        grib_context_free_persistent(c, e);
        return NULL;
    }
    if (start > slen) { /* to catch a -ve number passed to start */
        grib_context_log(c, GRIB_LOG_ERROR, "Invalid substring: start=%lu", start);
        grib_context_free_persistent(c, e);
        return NULL;
    }
    if (start + length > slen) {
        grib_context_log(c, GRIB_LOG_ERROR, "Invalid substring: start(=%lu)+length(=%lu) > length('%s'))", start, length, value);
        grib_context_free_persistent(c, e);
        return NULL;
    }

    memcpy(v, value + start, length);
    e->base.cclass = grib_expression_class_sub_string;
    e->value       = grib_context_strdup_persistent(c, v);
    return (grib_expression*)e;
}

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