#ifndef INCLUDED_GAI_FSM_H
#define INCLUDED_GAI_FSM_H

#ifndef INCLUDED_OS_TYPES_H
#include <os_types.h>
#endif /*INCLUDED_OS_TYPES_H*/

#ifndef INCLUDED_OS_COMPILER_H
#include <os_compiler.h>
#endif /*INCLUDED_OS_COMPILER_H*/

#ifndef INCLUDED_OS_LIST_H
#include <os_list.h>
#endif /*INCLUDED_OS_LIST_H*/

#ifndef INCLUDED_GAI_ACTION_H
#include <gai_action.h>
#endif /*INCLUDED_GAI_ACTION_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct gai_fsm_state_t gai_fsm_state_t;
typedef struct gai_fsm_transition_t gai_fsm_transition_t;
typedef struct gai_fsm_t gai_fsm_t;

typedef os_bool_t (*gai_fsm_evaluator_t)(gai_fsm_t* self, gai_fsm_transition_t* transition, void* ud);

struct gai_fsm_state_t{
    os_list_node_t      node;
    os_int_t            id;
    os_list_t           transition_list;
    gai_action_t        action;
};

struct gai_fsm_transition_t{
    os_list_node_t      node;
    os_int_t            from_state_id;
    os_int_t            to_state_id;
    gai_fsm_evaluator_t evaluator;
    void* userdata;
};

struct gai_fsm_t{
    gai_fsm_state_t*    current_state_p;
    os_list_t           state_list;
    void* userdata;
};

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

OS_STATIC_FORCE_INLINE
void gai_fsm_init(gai_fsm_t* self, void* userdata){
    self->current_state_p = 0;
    os_list_init(&self->state_list);
    self->userdata = userdata;
}

OS_STATIC_FORCE_INLINE
void gai_fsm_add_state(gai_fsm_t* self, gai_fsm_state_t * state){
    os_list_insert_after(&self->state_list, &state->node);
}

OS_STATIC_FORCE_INLINE
void gai_fsm_add_transition(gai_fsm_t* self, gai_fsm_transition_t* transition){
    os_list_node_t* p_node;
    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
        if(transition->from_state_id != p_state->id){
            continue;
        }
        os_list_insert_after(&p_state->transition_list, &transition->node);
        break;
    }
}


OS_STATIC_FORCE_INLINE
gai_action_status_t gai_fsm_status(gai_fsm_t* self){
    if(self->current_state_p){
        return self->current_state_p->action.status;
    }
    return kGaiActionStatus_UnInitialized;
}


OS_STATIC_FORCE_INLINE
gai_fsm_transition_t* gai_fsm_find_transition(gai_fsm_t* self, os_int_t from_state_id, os_int_t to_state_id){
    gai_fsm_state_t * p_from_state = 0;
    os_list_node_t* p_node;
    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
        if(p_state->id==from_state_id){
            p_from_state = p_state;
            break;
        }
    }
    if(p_from_state==0){
        return 0;
    }
    for(p_node = p_from_state->transition_list.next; p_node!=&p_from_state->transition_list; p_node= p_node->next){
        gai_fsm_transition_t* p_transition = os_list_member_of(p_node, gai_fsm_transition_t, node);
        if(p_transition->to_state_id == to_state_id){
            return p_transition;
        }
    }
    return 0;
}

OS_STATIC_FORCE_INLINE
gai_fsm_state_t* gai_fsm_find_state(gai_fsm_t* self, os_int_t state_id){
    os_list_node_t* p_node;
    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
        if(p_state->id==state_id){
            return p_state;
        }
    }
    return 0;
}


OS_STATIC_FORCE_INLINE
os_bool_t gai_fsm_has_transition(gai_fsm_t* self, os_int_t from_state_id, os_int_t to_state_id){
    return (gai_fsm_find_transition(self, from_state_id, to_state_id)!=0)?OS_TRUE:OS_FALSE;
}


OS_STATIC_FORCE_INLINE
os_bool_t gai_fsm_has_state(gai_fsm_t* self, os_int_t state_id){
    return (gai_fsm_find_state(self, state_id)!=0)?OS_TRUE:OS_FALSE;
}

OS_STATIC_FORCE_INLINE
void gai_fsm_set_state(gai_fsm_t* self, os_int_t state_id){
    gai_fsm_state_t* p_state = gai_fsm_find_state(self, state_id);
    if(p_state==0){
        return;
    }
    gai_action_Cleanup(&p_state->action);
    self->current_state_p = p_state;
    gai_action_Initialize(&p_state->action);
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

OS_STATIC_FORCE_INLINE
void gai_fsm_state_init(gai_fsm_state_t* self, os_int_t id,
                        gai_action_function_t onInitialize,
                        gai_action_update_function_t onUpdate,
                        gai_action_function_t onCleanup, void* userdata){
    os_list_init(&self->node);
    self->id = id;
    os_list_init(&self->transition_list);
    gai_action_init(&self->action, onInitialize, onUpdate, onCleanup, userdata);
}

OS_STATIC_FORCE_INLINE
void gai_fsm_transition_init(gai_fsm_transition_t* self,
                             os_int_t from_state_id,
                             os_int_t to_state_id,
                             gai_fsm_evaluator_t evaluator,
                             void* userdata){
    self->evaluator = evaluator;
    self->from_state_id = from_state_id;
    self->to_state_id = to_state_id;
    os_list_init(&self->node);
    self->userdata = userdata;
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */


void gai_fsm_update(gai_fsm_t* self, void* userdata);

#endif /*INCLUDED_GAI_FSM_H*/