/*
 * Copyright 2005-2016 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"
#include <assert.h>

/* 
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_long
   IMPLEMENTS = unpack_long
   IMPLEMENTS = init;dump
   MEMBERS=const char* date
   MEMBERS=const char* time
   MEMBERS=const char* step
   MEMBERS=const char* stepUnits
   MEMBERS=const char* year
   MEMBERS=const char* month
   MEMBERS=const char* day
   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 "accessor.class" and rerun ./make_class.pl

*/

static int unpack_long(grib_accessor*, long* val,size_t *len);
static void dump(grib_accessor*, grib_dumper*);
static void init(grib_accessor*,const long, grib_arguments* );
static void init_class(grib_accessor_class*);

typedef struct grib_accessor_validity_date {
    grib_accessor          att;
/* Members defined in gen */
/* Members defined in long */
/* Members defined in validity_date */
	const char* date;
	const char* time;
	const char* step;
	const char* stepUnits;
	const char* year;
	const char* month;
	const char* day;
} grib_accessor_validity_date;

extern grib_accessor_class* grib_accessor_class_long;

static grib_accessor_class _grib_accessor_class_validity_date = {
    &grib_accessor_class_long,                      /* super                     */
    "validity_date",                      /* name                      */
    sizeof(grib_accessor_validity_date),  /* size                      */
    0,                           /* inited */
    &init_class,                 /* init_class */
    &init,                       /* init                      */
    0,                  /* post_init                      */
    0,                    /* free mem                       */
    &dump,                       /* describes himself         */
    0,                /* get length of section     */
    0,              /* get length of string      */
    0,                /* get number of values      */
    0,                 /* get number of bytes      */
    0,                /* get offset to bytes           */
    0,            /* get native type               */
    0,                /* get sub_section                */
    0,               /* grib_pack procedures long      */
    0,               /* grib_pack procedures long      */
    0,                  /* grib_pack procedures long      */
    &unpack_long,                /* grib_unpack procedures long    */
    0,                /* grib_pack procedures double    */
    0,              /* grib_unpack procedures double  */
    0,                /* grib_pack procedures string    */
    0,              /* grib_unpack procedures string  */
    0,                 /* grib_pack procedures bytes     */
    0,               /* grib_unpack procedures bytes   */
    0,            /* pack_expression */
    0,              /* notify_change   */
    0,                /* update_size   */
    0,            /* preferred_size   */
    0,                    /* resize   */
    0,      /* nearest_smaller_value */
    0,                       /* next accessor    */
    0,                    /* compare vs. another accessor   */
    0,     /* unpack only ith value          */
    0,     /* unpack a subarray         */
    0,             		/* clear          */
};


grib_accessor_class* grib_accessor_class_validity_date = &_grib_accessor_class_validity_date;


static void init_class(grib_accessor_class* c)
{
	c->next_offset	=	(*(c->super))->next_offset;
	c->string_length	=	(*(c->super))->string_length;
	c->value_count	=	(*(c->super))->value_count;
	c->byte_count	=	(*(c->super))->byte_count;
	c->byte_offset	=	(*(c->super))->byte_offset;
	c->get_native_type	=	(*(c->super))->get_native_type;
	c->sub_section	=	(*(c->super))->sub_section;
	c->pack_missing	=	(*(c->super))->pack_missing;
	c->is_missing	=	(*(c->super))->is_missing;
	c->pack_long	=	(*(c->super))->pack_long;
	c->pack_double	=	(*(c->super))->pack_double;
	c->unpack_double	=	(*(c->super))->unpack_double;
	c->pack_string	=	(*(c->super))->pack_string;
	c->unpack_string	=	(*(c->super))->unpack_string;
	c->pack_bytes	=	(*(c->super))->pack_bytes;
	c->unpack_bytes	=	(*(c->super))->unpack_bytes;
	c->pack_expression	=	(*(c->super))->pack_expression;
	c->notify_change	=	(*(c->super))->notify_change;
	c->update_size	=	(*(c->super))->update_size;
	c->preferred_size	=	(*(c->super))->preferred_size;
	c->resize	=	(*(c->super))->resize;
	c->nearest_smaller_value	=	(*(c->super))->nearest_smaller_value;
	c->next	=	(*(c->super))->next;
	c->compare	=	(*(c->super))->compare;
	c->unpack_double_element	=	(*(c->super))->unpack_double_element;
	c->unpack_double_subarray	=	(*(c->super))->unpack_double_subarray;
	c->clear	=	(*(c->super))->clear;
}

/* END_CLASS_IMP */

/* Table of multipliers to convert step units to minutes */
static double u2m[] =  {
        1,         /* index 0:  minutes  */
        60,        /* index 1:  hour     */
        24*60,     /* index 2:  day      */
        24*60*30,  /* index 3:  month    */
        -1,        /* index 4:  year     */
        -1,        /* index 5:  decade   */
        -1,        /* index 6:  30 years */
        -1,        /* index 7:  century  */
        -1,        /* index 8:  RESERVED */
        -1,        /* index 9:  RESERVED */
        3*60,      /* index 10: 3 hours  */
        6*60,      /* index 11: 6 hours  */
        12*60,     /* index 12: 12 hours */
        1/60.0,    /* index 13: seconds  */
        15,        /* index 14: 15 mins  */
        30         /* index 15: 30 mins  */
};

static long convert_to_minutes(long step, long stepUnits)
{
    double result = 0;
    if (stepUnits == 0)  return step;    /* unit=minutes so no change */
    if (stepUnits == 1)  return step*60; /* unit=hours */
    if (stepUnits == 13) return step/60; /* unit=seconds */
    /* Assert( stepUnits < sizeof(u2m)/sizeof(u2m[0]) ); */

    result = step*u2m[stepUnits];
    return (long)result;
}

static void init(grib_accessor* a,const long l, grib_arguments* c)
{
    grib_accessor_validity_date* self = (grib_accessor_validity_date*)a;
    int n = 0;

    self->date = grib_arguments_get_name(a->parent->h,c,n++);
    self->time = grib_arguments_get_name(a->parent->h,c,n++);
    self->step = grib_arguments_get_name(a->parent->h,c,n++);
    self->stepUnits = grib_arguments_get_name(a->parent->h,c,n++);
    self->year = grib_arguments_get_name(a->parent->h,c,n++);
    self->month = grib_arguments_get_name(a->parent->h,c,n++);
    self->day = grib_arguments_get_name(a->parent->h,c,n++);

    a->flags |= GRIB_ACCESSOR_FLAG_READ_ONLY;
}

static void dump(grib_accessor* a, grib_dumper* dumper)
{
    grib_dump_long(dumper,a,NULL);
}

static int unpack_long(grib_accessor* a, long* val, size_t *len)
{   
    grib_accessor_validity_date* self = (grib_accessor_validity_date*)a;
    int ret=0;
    long date = 0;
    long time = 0;
    long step = 0;
    long stepUnits = 0;
    long hours = 0, minutes=0, step_mins=0, tmp, tmp_hrs;

    if (self->year) {
        long year,month,day;
        if ((ret=grib_get_long_internal(a->parent->h, self->year,&year))!=GRIB_SUCCESS) return ret;
        if ((ret=grib_get_long_internal(a->parent->h, self->month,&month))!=GRIB_SUCCESS) return ret;
        if ((ret=grib_get_long_internal(a->parent->h, self->day,&day))!=GRIB_SUCCESS) return ret;
        *val=year*10000+month*100+day;
        return GRIB_SUCCESS;
    }
    if ((ret=grib_get_long_internal(a->parent->h, self->date,&date))!=GRIB_SUCCESS) return ret;
    if ((ret=grib_get_long_internal(a->parent->h, self->time,&time))!=GRIB_SUCCESS) return ret;
    if ((ret=grib_get_long_internal(a->parent->h, self->step,&step))!=GRIB_SUCCESS) return ret;

    if (self->stepUnits) {
        if ((ret=grib_get_long_internal(a->parent->h, self->stepUnits,&stepUnits))!=GRIB_SUCCESS) return ret;
        step_mins = convert_to_minutes(step, stepUnits);
    }

    minutes = time % 100;
    hours = time / 100;
    tmp = minutes + step_mins; /* add the step to our minutes */
    tmp_hrs = tmp/60;          /* how many hours and mins is that? */
    /* tmp_mins = tmp%60; */
    hours += tmp_hrs;          /* increment hours */

    date = grib_date_to_julian (date);
    /* does the new 'hours' exceed 24? if so increment julian */
    while(hours>=24) {
        date ++;
        hours -= 24;
    }
    /* GRIB-29: Negative forecast time */
    while(hours<0) {
        date--;
        hours += 24;
    }

    if(*len < 1)
        return GRIB_ARRAY_TOO_SMALL;

    *val = grib_julian_to_date(date);

    return GRIB_SUCCESS;
}
