#ifndef CFGEVAL_H
#define CFGEVAL_H 1

#include "tac_plus.h"

#include "utils.h"


struct entity;
typedef struct entity ENTITY;
enum invalidate_scan {
    IS_REQUEST = 0,
    IS_VALUE   = 1,
    IS_EVAL    = 2,
    IS_MAX     = 3
};

enum eval_result {
    ER_UNKNOWN,
    ER_FALSE,
    ER_TRUE
};

enum value_scan_func_result {
    VSFR_CONTINUE,	/* for value_scan_entity() it means 'not found' */
    VSFR_FOUND,		/* immediately return from the whole value_scan_entity() */
    VSFR_STOP		/* backtrack (stop) this branch, scan further; nevere returned by value_scan_entity() */
};

struct membership {
    struct tac_list_node parent_node;	/* to_child_membership_list , AKA legacy "member" */
    struct tac_list_node  child_node;	/* to_parent_membership_list */

    struct {
	unsigned seq;			/* corresponds to global request_scan_seq */
	struct tac_list_node virtual_membership_node;
    } request_scan;		/*   cfg_request() scanning */

    struct {
	unsigned seq;			/* corresponds to global eval_scan_seq */
	unsigned unsolved:1;		/* we haven't yet decreased
					 * parent_entity->eval_scan.unsolved_to_child_membership_num */
    } eval_scan;		/*     expr_eval() scanning, many per value_scan */

    struct expr *when;
};
#define MEMBERSHIP_TO_PARENT_ENTITY(membership) \
	(&TAC_MEMBER_STRUCT(ENTITY, tac_list_node_get_list(&(membership)->parent_node), to_child_membership_list ))
#define MEMBERSHIP_TO_CHILD_ENTITY(membership) \
	(&TAC_MEMBER_STRUCT(ENTITY, tac_list_node_get_list(&(membership)-> child_node), to_parent_membership_list))
#define PARENT_NODE_TO_MEMBERSHIP(parent_node_) \
	(&TAC_MEMBER_STRUCT(struct membership, (parent_node_), parent_node))
#define  CHILD_NODE_TO_MEMBERSHIP( child_node_) \
	(&TAC_MEMBER_STRUCT(struct membership, ( child_node_),  child_node))
#define UNSOLVED_CHILD_NODE_TO_MEMBERSHIP(unsolved_child_node_) \
	(&TAC_MEMBER_STRUCT(struct membership, (unsolved_child_node_), eval_scan.unsolved_child_node))
#define VIRTUAL_MEMBERSHIP_NODE_TO_MEMBERSHIP(virtual_membership_node_) \
	(&TAC_MEMBER_STRUCT(struct membership, (virtual_membership_node_), request_scan.virtual_membership_node))

struct expr {
    struct {
	unsigned seq;			/* corresponds to global eval_scan_seq */
	enum eval_result result;	/* known result of this whole branch */
	unsigned loop_reported:1;	/* prevent excessive logging */
    } request_scan;		/*   cfg_request() scanning */

    struct {
	unsigned seq;			/* corresponds to global eval_scan_seq */
	union {

	struct {		/* for S_host, S_user or S_group */
			/* connected to either "entity->eval_scan.notify_expr_list"
			 * or to global "eval_notified_expr_list"
			 */
	    struct tac_list_node notify_expr_node;	/* gets removed on this expr->seq!= */
	} entity;

	} u;
    } eval_scan;		/*     expr_eval() scanning, many per value_scan */

    struct membership *membership;	/* our owner */
    struct expr *parent;	/* NULL if we are the root expr */
				/* "parent" also (mis)used by expr_sink_{register,commit}() ! */
    struct expr *next;		/* used in childs of S_and / S_or */
    int type;			/* S_not, S_and, S_or, S_host, S_user or S_group */
    int line;
    union {

    struct {
	struct expr *child;
    } not;

    struct {
	struct expr *child_first;	/* linked by expr->next */
    } and_or;

    struct {		/* for S_host, S_user or S_group */
	const char *name;
	ENTITY *entity;
    } entity;

    } u;
};
#define EXPR_ENTITY_TO_NOTIFYING_ENTITY(expr_) \
	(&TAC_MEMBER_STRUCT(ENTITY, tac_list_node_get_list(&(expr_)->eval_scan.u.entity.notify_expr_node), eval_scan.notify_expr_list))
#define NOTIFY_EXPR_NODE_TO_EXPR(notify_expr_node_) \
	(&TAC_MEMBER_STRUCT(struct expr, (notify_expr_node_), eval_scan.u.entity.notify_expr_node))

typedef enum value_scan_func_result (*value_scan_func_t) TAC_ARGS((ENTITY *entity,void *func_data));
extern void (*value_scan_forward_seen_hook) TAC_ARGS((struct membership *membership));


extern int request_scan_user_known;	/* have we allowed to 'solve' S_user entities at all? */


extern void unlink_expr TAC_ARGS((struct expr *expr));
extern void free_expr TAC_ARGS((struct expr *expr));
extern void scan_free_entity TAC_ARGS((ENTITY *entity));
extern struct expr *new_expr TAC_ARGS((int type));
extern enum value_scan_func_result value_scan_entity TAC_ARGS((ENTITY *entity, int recurse, value_scan_func_t func, void *func_data));
extern struct membership *value_scan_backward TAC_ARGS((ENTITY *entity));
extern enum eval_result expr_eval TAC_ARGS((struct expr *expr_single));
extern struct expr *dupl_expr TAC_ARGS((const struct expr *in));
extern void scan_init_entity TAC_ARGS((ENTITY *entity));
extern struct membership *enlist_entity_direct TAC_ARGS((ENTITY *parent, ENTITY *child, struct expr *when));
extern struct membership *virtual_enlist_entity_direct TAC_ARGS((ENTITY *parent, ENTITY *child));
extern void scan_invalidate_entities_hashtable TAC_ARGS((void **hashtable, enum invalidate_scan what));
extern void request_scan_begin TAC_ARGS((void));
extern void eval_force_belong_entity TAC_ARGS((ENTITY *entity));
extern void expr_sink_register TAC_ARGS((struct expr *expr));
extern int expr_sink_commit TAC_ARGS((void));


#endif /* CFGEVAL_H */