#ifndef ATTRIB_H
#define ATTRIB_H

#include <stdbool.h>
#include <util/variant.h>
#ifdef __cplusplus
extern "C" {
#endif

    union variant;
    struct gamedata;
    struct storage;
    typedef void(*afun) (void);

    typedef struct attrib {
        const struct attrib_type *type;
        union variant data;
        /* internal data, do not modify: */
        struct attrib *next;        /* next attribute in the list */
        struct attrib *nexttype;    /* skip to attribute of a different type */
    } attrib;

#define ATF_UNIQUE   (1<<0)     /* only one per attribute-list */
#define ATF_PRESERVE (1<<1)     /* preserve order in list. append to back */
#define ATF_USER_DEFINED (1<<2) /* use this to make udf */

    typedef struct attrib_type {
        const char *name;
        void(*initialize) (union variant *);
        void(*finalize) (union variant *);
        int(*age) (struct attrib *, void *owner);
        /* age returns 0 if the attribute needs to be removed, !=0 otherwise */
        void(*write) (const union variant *, const void *owner, struct storage *);
        int(*read) (union variant *, void *owner, struct gamedata *);       /* return AT_READ_OK on success, AT_READ_FAIL if attrib needs removal */
        void(*upgrade) (struct attrib **alist, struct attrib *a);
        unsigned int flags;
        /* ---- internal data, do not modify: ---- */
        struct attrib_type *nexthash;
        unsigned int hashkey;
    } attrib_type;

    void at_register(attrib_type * at);
    void at_deprecate(const char * name, int (*reader)(variant *, void *, struct gamedata *));
    struct attrib_type *at_find(const char *name);

    void write_attribs(struct storage *store, struct attrib *alist, const void *owner);
    int read_attribs(struct gamedata *store, struct attrib **alist, void *owner);

    attrib *a_select(attrib * a, const void *data, bool(*compare) (const attrib *, const void *));
    attrib *a_find(attrib * a, const attrib_type * at);
    attrib *a_add(attrib ** pa, attrib * at);
    int a_remove(attrib ** pa, attrib * at);
    void a_removeall(attrib ** a, const attrib_type * at);
    attrib *a_new(const attrib_type * at);
    int a_age(attrib ** attribs, void *owner);

    void a_free_voidptr(union variant *v);
    int a_read_orig(struct gamedata *data, attrib ** attribs, void *owner);
    int a_read(struct gamedata *data, attrib ** attribs, void *owner);
    void a_write(struct storage *store, const attrib * attribs, const void *owner);

    int a_readint(union variant *v, void *owner, struct gamedata *);
    void a_writeint(const union variant *v, const void *owner,
        struct storage *store);
    int a_readshorts(union variant *v, void *owner, struct gamedata *);
    void a_writeshorts(const union variant *v, const void *owner,
        struct storage *store);
    int a_readchars(union variant *v, void *owner, struct gamedata *);
    void a_writechars(const union variant *v, const void *owner,
        struct storage *store);
    int a_readstring(union variant *v, void *owner, struct gamedata *);
    void a_writestring(const union variant *v, const void *owner,
        struct storage *);
    void a_finalizestring(union variant *v);

    void attrib_done(void);

#define DEFAULT_AGE NULL
#define DEFAULT_INIT NULL
#define DEFAULT_FINALIZE NULL
#define NO_WRITE NULL
#define NO_READ NULL

#define AT_READ_OK 0
#define AT_READ_FAIL -1
#define AT_READ_DEPR 1 /* a deprecated attribute was read, should run a_upgrade */

#define AT_AGE_REMOVE 0         /* remove the attribute after calling age() */
#define AT_AGE_KEEP 1           /* keep the attribute for another turn */

#ifdef __cplusplus
}
#endif
#endif