/*
 * Yet another daemon library especially designed to be used
 * with libsxmp based daemons.
 *
 * (c) Alexander Vdolainen 2016 <avdolainen@zoho.com>
 *
 * libsxmp is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libsxmp 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.";
 *
 */

#ifndef __YDAEMON_YDAEMON_H__
#define __YDAEMON_YDAEMON_H__

#include <stdint.h>
#include <time.h>
#include <sys/types.h>
#include <pthread.h>

#include <tdata/usrtc.h>
#include <tdata/idx_allocator.h>
#include <sexpr/sexp.h>

/* some syntax */

/**
 * --values (variables)
 */
#define VAR_CREATE_GROUP  "create-var-group"
#define VAR_SET           "var-set"
/**
 * --modules
 * (%MODULE_ADD_SX '<name> <type>)  -- add a module to the list of available modules
 * (%MODULE_SET_SX '<name> (:%MODULE_PREFIX|%MODULE_PATHNAME|%MODULE_CNFPATH *<value>))
 *               *value might be the following:
 *                 a. in case of double or single quote - will be taken as is
 *                 b. without quotes will be interpreted as variable (must be defined before this expression)
 */
#define MODULE_ADD_SX  "module-add"
#define MODULE_SET_SX  "module-set" /** { */
/* module config values for _SET_SX */
#define MODULE_PREFIX    "prefix"
#define MODULE_PATHNAME  "pathname"
#define MODULE_CNFPATH   "config-path"
/** } */
#define MODULE_LOAD_SX   "module-load"
#define MODULE_RUN_SX    "module-run"
/* internal functions */
#define SCMOBJECT        "object"
/* functions for the logs */
#define YDOPENLOGS       "yd-open-logfile"

/* limits */
#define MAX_SCM_FUNCTIONS  16384

#define MAX_SERVICES  8192
#define MAX_MODULES   4096

enum {
  SCINT = 0,
  SCCSTR,
  SCOBJECTPTR,
  SCUNDEFINED,
};

typedef struct __scm_ret {
  uint8_t serr;
  uint8_t type;
  uint32_t len;
  union {
    void *ret;
    struct {
      int32_t ec;
      uint32_t ru32;
    };
  };
} scret_t;

#define RETURN_SRET_SERR(r, e) (r).serr = e; return r
#define RETURN_SRET_IRES(r, e) (r).serr = 0; (r).type = SCINT; (r).ec = e; \
                                                                  return r
#define RETURN_SRET_ORES(r, e) (r).serr = 0; (r).type = SCOBJECTPTR; (r).ret = (e); \
                                                                     return r

struct __ydaemon_context_type;

/**
 * @brief Type used to describe scm function
 *
 * It contains name i.e. keyword, pointer to the
 * function itself and optional pointer to the
 * implementation specific data. It packs to usrtc
 * search structure.
 */
typedef struct __scm_func {
  char *name;
  scret_t (*call)(struct __ydaemon_context_type *, sexp_t *, void *);
  void *priv;
  usrtc_node_t node;
} scm_function_t;

/**
 * @brief Type used to describe a tree of scm functions
 *
 * It contains a search structure with packed
 * scm_function_t set and also contain special
 * private pointer that might be optionally used
 * by implementation.
 */
typedef struct __scm_func_tree {
  usrtc_t functions;
  void *priv;
} scm_function_tree_t;

/**
 * @brief Values types
 *
 * Describes the type of value
 * @see zdc_conf_val_t
 */
typedef enum {
  STRING = 0,
  INT,
  UINT,
  LONG,
  ULONG,
  BLOB,
  SEXPR,
  CUSTOM,
} ydc_val_type_t;

/**
 * @brief configuration event
 *
 * Type used to describe events occured with values
 */
typedef enum {
  YC_EVENT_ADD,
  YC_EVENT_MODIFY,
  YC_EVENT_DESTROY,
  YC_EVENT_ATTACH,
} ydc_event_t;

/**
 * @brief Type used to fit all required parameters
 *
 * It contain mode, system settings and a lot of other
 * config defined parameters.
 */
typedef struct __ym_conf {
  /* parameters groups */
  usrtc_t p_groups; /**< Parameters groups */
  /* functions tree */
  void *init_funcs;
  /* locking */
  pthread_rwlock_t grp_lock; /**< Locking for groups */
  pthread_mutex_t conf_lock; /**< Locking for state change, function ops, system io */
} ydc_conf_t;

/**
 * @brief Type of the parameters group
 *
 * Store values.
 */
typedef struct __ym_pgroup {
  usrtc_t values;
  usrtc_node_t unode;
  char *name;
  pthread_rwlock_t val_lock;
} ydc_pgroup_t;

/**
 * @brief Type used to describe value
 *
 * Used to store value.
 */
typedef struct __ym_conf_value {
  usrtc_node_t unode;
  ydc_val_type_t type;
  int len;
  char *name;
  void *value;
  void (*on_eventv)(struct __ym_conf_value *,
                    struct __ym_conf_value *,
                    ydc_conf_t *, ydc_event_t);
  void *priv;
} ydc_conf_val_t;

typedef struct __ydaemon_log_type {
  FILE *logstream;
  int verbose_level;
  int se;
} yd_log_t;

typedef struct __ydaemon_context_type {
  usrtc_t *services;
  usrtc_t *modules;
  scm_function_tree_t *func; /** < functions for configuration and processing */
  ydc_conf_t *values;  /** < values stored by the groups */
  yd_log_t *logcontext;
  int flags;
  pthread_rwlock_t modlock;
  pthread_mutex_t looplock;
  int daemon;
} yd_context_t;

#define yd_mod_ctx_wrlock(n)  pthread_rwlock_wrlock(&(n)->modlock)
#define yd_mod_ctx_rdlock(n)  pthread_rwlock_rdlock(&(n)->modlock)
#define yd_mod_ctx_unlock(n)  pthread_rwlock_unlock(&(n)->modlock)

typedef enum {
  YD_SERVICE_MUX = 0,
  YD_SXMP_MOD,
  YD_DATASTORE_MOD,
  YD_OTHER,
} yd_mod_type_t;

typedef struct __ydaemon_module {
  char *name;
  char *pathname;
  char *cnfname;
  char *prefix;
  void *dlhandle;
  void *(*getobject)(void *, const char *);
  int (*shutdown)(yd_context_t *);
  int (*preinit)(yd_context_t *);
  int (*init)(yd_context_t *);
  int (*run)(yd_context_t *);
  yd_mod_type_t type;
  int flags;
  usrtc_node_t node;
} yd_mod_t;

/* functions defines for modules */
#define def_shutdown(PREFIX)  int PREFIX ## _shutdown(yd_context_t *ctx)
#define def_preinit(PREFIX)  int PREFIX ## _preinit(yd_context_t *ctx)
#define def_init(PREFIX)  int PREFIX ## _init(yd_context_t *ctx)
#define def_run(PREFIX)  int PREFIX ## _run(yd_context_t *ctx)
#define def_getobject(PREFIX)  void* PREFIX ## _getobject(void *priv, const char *oname)
/* function arguments macros */
#define def_ctx   ctx
#define defpriv   priv
#define defoname  oname

#define yd_mod_set_prefix(n, p)  (n)->prefix = (p)
#define yd_mod_set_pathname(n, p)  (n)->pathname = (p)
#define yd_mod_set_cfgpath(n, p)  (n)->cnfname = (p)

#define yd_mod_preinit(n)  \
  { memset((n), 0, sizeof(yd_mod_t)); usrtc_node_init((n)->node, (n)); }

int yd_mod_init(yd_context_t *, yd_mod_t *);

int yd_mod_get(yd_context_t *, const char *, yd_mod_t **);

int yd_mod_load(yd_context_t *, yd_mod_t *);

int yd_mod_run(yd_context_t *, yd_mod_t *);

int yd_mod_shutdown(yd_context_t *, yd_mod_t *);

void *yd_mod_getobject(yd_context_t *, yd_mod_t *, void *, const char *);

void *yd_mod_getsym(yd_context_t *, yd_mod_t *, const char *);

typedef struct __ydaemon_service {
  char *name; /* name of the service */
  void *ops; /* the subject to think about ... */
  void *connection; /* as backends private data */
  void *conf; /* special configuration */
  usrtc_node_t node;
} yd_service_t;

#define yd_ctx_values(c)  (c)->values

int yd_init_ctx(yd_context_t *);

int yd_eval_ctx(yd_context_t *, const char *);

scret_t yd_eval_sexp(yd_context_t *, sexp_t *);

int yd_mainloop(yd_context_t *);

void yd_mainloop_exit(yd_context_t *);

int yd_set_daemonize(yd_context_t *, int);

/* modules related functions */
int yd_mod_add(yd_context_t *, const char *, yd_mod_type_t);

/* internal functions API */
void scm_func_tree_free(scm_function_tree_t *pt);

int scm_func_tree_init(scm_function_tree_t **pt, void *priv);

int scm_func_tree_insert(yd_context_t *zdx, const char *name,
                         scret_t (*call)(yd_context_t *, sexp_t *, void *),
                         void *priv);

int scm_func_tree_insert_t(yd_context_t *zdx, scm_function_t *f);

scret_t scm_func_tree_call(yd_context_t *zdx, void *cnf, sexp_t *sx,
                           char *name);

int scm_func_tree_delete(yd_context_t *zdx, char *name);

/* variables related functions */
int ydc_conf_init(ydc_conf_t *);

int ydc_conf_create_pgroup(ydc_conf_t *, char *);

int ydc_conf_get_val(ydc_conf_t *, const char *, ydc_conf_val_t **);

int ydc_conf_add_val_p(ydc_conf_t *, const char *, int);

/* some internal stuff */
#define UNIT_TESTS  1
#ifdef UNIT_TESTS
#define blub  printf("%d at %s\n", __LINE__, __FUNCTION__)
#endif

/* logging */
enum {
  YL_DEBUG = 0,
  YL_INFO,
  YL_WARN,
  YL_ERROR,
};

void ydlog(yd_context_t *ctx, int olvl, const char *fmt, ...);

void yddaemon(yd_context_t *ctx);

/* object storage */

#define MAX_OBJECTS  65535

typedef struct __ostore_type {
  usrtc_t objects;
  pthread_rwlock_t rwlock;
} obj_store_t;

typedef struct __ostore_node_type {
  char *name;
  void *objdata;
  usrtc_node_t node;
} obj_store_node_t;

int obj_store_init(obj_store_t *);

int obj_store_set(obj_store_t *, const char *, void *);

int obj_store_get(obj_store_t *, const char *, void **);

int obj_store_remove(obj_store_t *, const char *);

#endif /* __YDAEMON_YDAEMON_H__ */