/** The internal datastructure for a sample of simulation data.
 *
 * @file
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#pragma once

#include <villas/atomic.h>

#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <time.h>

#ifdef __cplusplus
extern "C"{
#endif

/* Forward declarations */
struct pool;

/** The length of a sample datastructure with \p values values in bytes. */
#define SAMPLE_LEN(len)	(sizeof(struct sample) + SAMPLE_DATA_LEN(len))

/** The length of a sample data portion of a sample datastructure with \p values values in bytes. */
#define SAMPLE_DATA_LEN(len)	((len) * sizeof(double))

/** The offset to the beginning of the data section. */
#define SAMPLE_DATA_OFFSET(smp)	((char *) (smp) + offsetof(struct sample, data))

enum sample_data_format {
	SAMPLE_DATA_FORMAT_FLOAT = 0,
	SAMPLE_DATA_FORMAT_INT   = 1
};

/** Parts of a sample that can be serialized / de-serialized by the IO formats */
enum sample_flags {
	SAMPLE_HAS_ORIGIN	= (1 << 0), /**< Include origin timestamp in output. */
	SAMPLE_HAS_RECEIVED	= (1 << 1), /**< Include receive timestamp in output. */
	SAMPLE_HAS_OFFSET	= (1 << 2), /**< Include offset (received - origin timestamp) in output. */
	SAMPLE_HAS_SOURCE	= (1 << 3), /**< This sample has a valid sample::source field. */
	SAMPLE_HAS_ID		= (1 << 4), /**< This sample has a valid sample::id field. */
	SAMPLE_HAS_SEQUENCE	= (1 << 5), /**< Include sequence number in output. */
	SAMPLE_HAS_VALUES	= (1 << 6), /**< Include values in output. */
	SAMPLE_HAS_FORMAT	= (1 << 7), /**< This sample has a valid sample::format field. */
	SAMPLE_HAS_ALL		= (1 << 7) - 1, /**< Enable all output options. */

	SAMPLE_IS_FIRST		= (1 << 16), /**< This sample is the first of a new simulation case */
	SAMPLE_IS_LAST		= (1 << 17), /**< This sample is the last of a running simulation case */
	SAMPLE_IS_REORDERED	= (1 << 18), /**< This sample is reordered. */

//	SAMPLE_DO_DROP		= (1 << 19),  /**< This sample should be dropped. */
//	SAMPLE_DO_SKIP		= (1 << 20)  /**< This sample was skipped by a previous hook. */
};

struct sample {
	int sequence;		/**< The sequence number of this sample. */
	int length;		/**< The number of values in sample::values which are valid. */
	int capacity;		/**< The number of values in sample::values for which memory is reserved. */
	int flags;		/**< Flags are used to store binary properties of a sample. */

	struct node *source;	/**< The node from which this sample originates. */
	struct node *destination; /**< The node to which this sample will be sent. */

	atomic_int refcnt;	/**< Reference counter. */
	ptrdiff_t pool_off;	/**< This sample belongs to this memory pool (relative pointer). See sample_pool(). */

	/** A long bitfield indicating the number representation of the first 64 values in sample::data[].
	 *
	 * @see sample_data_format
	 */
	uint64_t format;

	/** All timestamps are seconds / nano seconds after 1.1.1970 UTC */
	struct {
		struct timespec origin;		/**< The point in time when this data was sampled. */
		struct timespec received;	/**< The point in time when this data was received. */
	} ts;

	/** The values. */
	union {
		double  f;	/**< Floating point values. */
		int64_t i;	/**< Integer values. */
	} data[];		/**< Data is in host endianess! */
};

#define SAMPLE_NON_POOL PTRDIFF_MIN

/** Get the address of the pool to which the sample belongs. */
#define sample_pool(s) ((s)->pool_off == SAMPLE_NON_POOL ? NULL : (struct pool *) ((char *) (s) + (s)->pool_off))

struct sample * sample_alloc(struct pool *p);

struct sample * sample_alloc_mem(int capacity);

struct sample * sample_clone(struct sample *smp);

void sample_free(struct sample *s);

/** Request \p cnt samples from memory pool \p p and initialize them.
 *  The reference count will already be set to 1.
 *  Use the sample_get() function to increase it. */
int sample_alloc_many(struct pool *p, struct sample *smps[], int cnt);

/** Release an array of samples back to their pools */
void sample_free_many(struct sample *smps[], int cnt);

/** Increase reference count of sample */
int sample_get(struct sample *s);

/** Decrease reference count and release memory if last reference was held. */
int sample_put(struct sample *s);

int sample_copy(struct sample *dst, struct sample *src);


/** Compare two samples */
int sample_cmp(struct sample *a, struct sample *b, double epsilon, int flags);

int sample_clone_many(struct sample *clones[], struct sample *origs[], int cnt);
int sample_copy_many(struct sample *dsts[], struct sample *srcs[], int cnt);
int sample_get_many(struct sample *smps[], int cnt);
int sample_put_many(struct sample *smps[], int cnt);

/** Get number representation for a single value of a sample. */
int sample_get_data_format(struct sample *s, int idx);

/** Set number representation for a single value of a sample. */
int sample_set_data_format(struct sample *s, int idx, enum sample_data_format fmt);

#ifdef __cplusplus
}
#endif