/*
 * Copyright (c) 2015 Michal Koutny
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Unit terminology and OOP based on systemd.
 */
#ifndef SYSMAN_UNIT_H
#define SYSMAN_UNIT_H

#include <adt/hash_table.h>
#include <adt/list.h>
#include <conf/configuration.h>
#include <conf/ini.h>
#include <conf/text_parse.h>
#include <fibril_synch.h>

typedef enum {
	UNIT_TYPE_INVALID = -1,
	UNIT_CONFIGURATION = 0,
	UNIT_MOUNT,
	UNIT_SERVICE,
	UNIT_TARGET
} unit_type_t;

typedef enum {
	STATE_EMBRYO = 0,
	STATE_STARTING,
	STATE_STARTED,
	STATE_STOPPED,
	STATE_FAILED
} unit_state_t;

/* Forward declarations */
typedef struct unit_vmt unit_vmt_t;
struct unit_vmt;

typedef struct job job_t;
struct job;

typedef struct {
	/** Link to name-to-unit hash table */
	ht_link_t units_by_name;

	/** Link to list of all units */
	link_t units;

	/** Link to queue, when BFS traversing units */
	link_t bfs_link;

	/** Auxiliary job created during BFS traverse, its presence serves also
	 * as BFS tag */
	job_t *bfs_job;

	/** Job assigned to unit in transitional state */
	job_t *job;

	unit_type_t type;
	char *name;

	unit_state_t state;

	list_t dependencies;
	list_t dependants;
} unit_t;

#include "unit_cfg.h"
#include "unit_mnt.h"
#include "unit_tgt.h"
#include "unit_svc.h"

#define DEFINE_CAST(NAME, TYPE, ENUM_TYPE)                                     \
	static inline TYPE *CAST_##NAME(unit_t *u)                             \
	{                                                                      \
		if (u->type == ENUM_TYPE)                                      \
			return (TYPE *)u;                                      \
		else                                                           \
			return NULL;                                           \
	}                                                                      \

DEFINE_CAST(CFG, unit_cfg_t, UNIT_CONFIGURATION)
DEFINE_CAST(MNT, unit_mnt_t, UNIT_MOUNT)
DEFINE_CAST(TGT, unit_tgt_t, UNIT_TARGET)
DEFINE_CAST(SVC, unit_svc_t, UNIT_SERVICE)

struct unit_vmt {
	size_t size;

	void (*init)(unit_t *);

	void (*destroy)(unit_t *);

	int (*load)(unit_t *, ini_configuration_t *, text_parse_t *);

	int (*start)(unit_t *);

	void (*exposee_created)(unit_t *);

	void (*fail)(unit_t *);
};

extern unit_vmt_t *unit_type_vmts[];

#define DEFINE_UNIT_VMT(PREFIX)                                                \
	unit_vmt_t PREFIX##_vmt = {                                            \
		.size            = sizeof(PREFIX##_t),                         \
		.init            = &PREFIX##_init,                             \
		.load            = &PREFIX##_load,                             \
		.destroy         = &PREFIX##_destroy,                          \
		.start           = &PREFIX##_start,                            \
		.exposee_created = &PREFIX##_exposee_created,                  \
		.fail            = &PREFIX##_fail                              \
	};

#define UNIT_VMT(UNIT) unit_type_vmts[(UNIT)->type]

extern unit_t *unit_create(unit_type_t);
extern void unit_destroy(unit_t **);

extern int unit_load(unit_t *, ini_configuration_t *, text_parse_t *);
extern int unit_start(unit_t *);
extern void unit_exposee_created(unit_t *);
extern void unit_fail(unit_t *);

extern void unit_notify_state(unit_t *);

extern unit_type_t unit_type_name_to_type(const char *);

extern const char *unit_name(const unit_t *);

extern bool unit_parse_unit_list(const char *, void *, text_parse_t *, size_t);

#endif