/**
 * @file lv_gridnav.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "lv_gridnav.h"
#if LV_USE_GRIDNAV

#include "../../../misc/lv_assert.h"
#include "../../../misc/lv_math.h"
#include "../../../core/lv_indev.h"

/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/
typedef struct {
    lv_gridnav_ctrl_t ctrl;
    lv_obj_t * focused_obj;
} lv_gridnav_dsc_t;

typedef enum {
    FIND_LEFT,
    FIND_RIGHT,
    FIND_TOP,
    FIND_BOTTOM,
    FIND_NEXT_ROW_FIRST_ITEM,
    FIND_PREV_ROW_LAST_ITEM,
    FIND_FIRST_ROW,
    FIND_LAST_ROW,
} find_mode_t;

/**********************
 *  STATIC PROTOTYPES
 **********************/
static void gridnav_event_cb(lv_event_t * e);
static lv_obj_t * find_chid(lv_obj_t * obj, lv_obj_t * start_child, find_mode_t mode);
static lv_obj_t * find_first_focusable(lv_obj_t * obj);
static lv_obj_t * find_last_focusable(lv_obj_t * obj);
static bool obj_is_focuable(lv_obj_t * obj);
static lv_coord_t get_x_center(lv_obj_t * obj);
static lv_coord_t get_y_center(lv_obj_t * obj);

/**********************
 *  STATIC VARIABLES
 **********************/

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

void lv_gridnav_add(lv_obj_t * obj, lv_gridnav_ctrl_t ctrl)
{
    lv_gridnav_remove(obj); /*Be sure to not add gridnav twice*/

    lv_gridnav_dsc_t * dsc = lv_mem_alloc(sizeof(lv_gridnav_dsc_t));
    LV_ASSERT_MALLOC(dsc);
    dsc->ctrl = ctrl;
    dsc->focused_obj = NULL;
    lv_obj_add_event_cb(obj, gridnav_event_cb, LV_EVENT_ALL, dsc);

    lv_obj_clear_flag(obj, LV_OBJ_FLAG_SCROLL_WITH_ARROW);
}

void lv_gridnav_remove(lv_obj_t * obj)
{
    lv_gridnav_dsc_t * dsc = lv_obj_get_event_user_data(obj, gridnav_event_cb);
    if(dsc == NULL) return; /* no gridnav on this object */

    lv_mem_free(dsc);
    lv_obj_remove_event_cb(obj, gridnav_event_cb);
}

void lv_gridnav_set_focused(lv_obj_t * cont, lv_obj_t * to_focus, lv_anim_enable_t anim_en)
{
    LV_ASSERT_NULL(to_focus);
    lv_gridnav_dsc_t * dsc = lv_obj_get_event_user_data(cont, gridnav_event_cb);
    if(dsc == NULL) {
        LV_LOG_WARN("`cont` is not a gridnav container");
        return;
    }

    if(obj_is_focuable(to_focus) == false) {
        LV_LOG_WARN("The object to focus is not focusable");
        return;
    }

    lv_obj_clear_state(dsc->focused_obj, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
    lv_obj_add_state(to_focus, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
    lv_obj_scroll_to_view(to_focus, anim_en);
    dsc->focused_obj = to_focus;

}

/**********************
 *   STATIC FUNCTIONS
 **********************/

static void gridnav_event_cb(lv_event_t * e)
{
    lv_obj_t * obj = lv_event_get_current_target(e);
    lv_gridnav_dsc_t * dsc = lv_event_get_user_data(e);
    lv_event_code_t code = lv_event_get_code(e);

    if(code == LV_EVENT_KEY) {
        uint32_t child_cnt = lv_obj_get_child_cnt(obj);
        if(child_cnt == 0) return;

        if(dsc->focused_obj == NULL) dsc->focused_obj = find_first_focusable(obj);
        if(dsc->focused_obj == NULL) return;

        uint32_t key = lv_event_get_key(e);
        lv_obj_t * guess = NULL;

        if(key == LV_KEY_RIGHT) {
            if((dsc->ctrl & LV_GRIDNAV_CTRL_SCROLL_FIRST) && lv_obj_has_flag(dsc->focused_obj, LV_OBJ_FLAG_SCROLLABLE) &&
               lv_obj_get_scroll_right(dsc->focused_obj) > 0) {
                lv_coord_t d = lv_obj_get_width(dsc->focused_obj) / 4;
                if(d <= 0) d = 1;
                lv_obj_scroll_by_bounded(dsc->focused_obj, -d, 0, LV_ANIM_ON);
            }
            else {
                guess = find_chid(obj, dsc->focused_obj, FIND_RIGHT);
                if(guess == NULL) {
                    if(dsc->ctrl & LV_GRIDNAV_CTRL_ROLLOVER) {
                        guess = find_chid(obj, dsc->focused_obj, FIND_NEXT_ROW_FIRST_ITEM);
                        if(guess == NULL) guess = find_first_focusable(obj);
                    }
                    else {
                        lv_group_focus_next(lv_obj_get_group(obj));
                    }
                }
            }
        }
        else if(key == LV_KEY_LEFT) {
            if((dsc->ctrl & LV_GRIDNAV_CTRL_SCROLL_FIRST) && lv_obj_has_flag(dsc->focused_obj, LV_OBJ_FLAG_SCROLLABLE) &&
               lv_obj_get_scroll_left(dsc->focused_obj) > 0) {
                lv_coord_t d = lv_obj_get_width(dsc->focused_obj) / 4;
                if(d <= 0) d = 1;
                lv_obj_scroll_by_bounded(dsc->focused_obj, d, 0, LV_ANIM_ON);
            }
            else {
                guess = find_chid(obj, dsc->focused_obj, FIND_LEFT);
                if(guess == NULL) {
                    if(dsc->ctrl & LV_GRIDNAV_CTRL_ROLLOVER) {
                        guess = find_chid(obj, dsc->focused_obj, FIND_PREV_ROW_LAST_ITEM);
                        if(guess == NULL) guess = find_last_focusable(obj);
                    }
                    else {
                        lv_group_focus_prev(lv_obj_get_group(obj));
                    }
                }
            }
        }
        else if(key == LV_KEY_DOWN) {
            if((dsc->ctrl & LV_GRIDNAV_CTRL_SCROLL_FIRST) && lv_obj_has_flag(dsc->focused_obj, LV_OBJ_FLAG_SCROLLABLE) &&
               lv_obj_get_scroll_bottom(dsc->focused_obj) > 0) {
                lv_coord_t d = lv_obj_get_height(dsc->focused_obj) / 4;
                if(d <= 0) d = 1;
                lv_obj_scroll_by_bounded(dsc->focused_obj, 0, -d, LV_ANIM_ON);
            }
            else {
                guess = find_chid(obj, dsc->focused_obj, FIND_BOTTOM);
                if(guess == NULL) {
                    if(dsc->ctrl & LV_GRIDNAV_CTRL_ROLLOVER) {
                        guess = find_chid(obj, dsc->focused_obj, FIND_FIRST_ROW);
                    }
                    else {
                        lv_group_focus_next(lv_obj_get_group(obj));
                    }
                }
            }
        }
        else if(key == LV_KEY_UP) {
            if((dsc->ctrl & LV_GRIDNAV_CTRL_SCROLL_FIRST) && lv_obj_has_flag(dsc->focused_obj, LV_OBJ_FLAG_SCROLLABLE) &&
               lv_obj_get_scroll_top(dsc->focused_obj) > 0) {
                lv_coord_t d = lv_obj_get_height(dsc->focused_obj) / 4;
                if(d <= 0) d = 1;
                lv_obj_scroll_by_bounded(dsc->focused_obj, 0, d, LV_ANIM_ON);
            }
            else {
                guess = find_chid(obj, dsc->focused_obj, FIND_TOP);
                if(guess == NULL) {
                    if(dsc->ctrl & LV_GRIDNAV_CTRL_ROLLOVER) {
                        guess = find_chid(obj, dsc->focused_obj, FIND_LAST_ROW);
                    }
                    else {
                        lv_group_focus_prev(lv_obj_get_group(obj));
                    }
                }
            }
        }
        else {
            if(lv_group_get_focused(lv_obj_get_group(obj)) == obj) {
                lv_event_send(dsc->focused_obj, LV_EVENT_KEY, &key);
            }
        }

        if(guess && guess != dsc->focused_obj) {
            lv_obj_clear_state(dsc->focused_obj, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
            lv_obj_add_state(guess, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
            lv_obj_scroll_to_view(guess, LV_ANIM_ON);
            dsc->focused_obj = guess;
        }
    }
    else if(code == LV_EVENT_FOCUSED) {
        if(dsc->focused_obj == NULL)  dsc->focused_obj = find_first_focusable(obj);
        if(dsc->focused_obj) {
            lv_obj_add_state(dsc->focused_obj, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
            lv_obj_scroll_to_view(dsc->focused_obj, LV_ANIM_OFF);
        }
    }
    else if(code == LV_EVENT_DEFOCUSED) {
        if(dsc->focused_obj) {
            lv_obj_clear_state(dsc->focused_obj, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
        }
    }
    else if(code == LV_EVENT_CHILD_CREATED) {
        lv_obj_t * child = lv_event_get_target(e);
        if(lv_obj_get_parent(child) == obj) {
            if(dsc->focused_obj == NULL) {
                dsc->focused_obj = child;
                if(lv_obj_has_state(obj, LV_STATE_FOCUSED)) {
                    lv_obj_add_state(child, LV_STATE_FOCUSED | LV_STATE_FOCUS_KEY);
                    lv_obj_scroll_to_view(child, LV_ANIM_OFF);
                }
            }
        }
    }
    else if(code == LV_EVENT_CHILD_DELETED) {
        /*This event bubble, so be sure this object's child was deleted.
         *As we don't know which object was deleted we can't make the next focused.
         *So make the first object focused*/
        lv_obj_t * target = lv_event_get_target(e);
        if(target == obj) {
            dsc->focused_obj = find_first_focusable(obj);
        }
    }
    else if(code == LV_EVENT_DELETE) {
        lv_gridnav_remove(obj);
    }
    else if(code == LV_EVENT_PRESSED || code == LV_EVENT_PRESSING || code == LV_EVENT_PRESS_LOST ||
            code == LV_EVENT_LONG_PRESSED || code == LV_EVENT_LONG_PRESSED_REPEAT ||
            code == LV_EVENT_CLICKED || code == LV_EVENT_RELEASED) {
        if(lv_group_get_focused(lv_obj_get_group(obj)) == obj) {
            /*Forward press/release related event too*/
            lv_indev_type_t t = lv_indev_get_type(lv_indev_get_act());
            if(t == LV_INDEV_TYPE_ENCODER || t == LV_INDEV_TYPE_KEYPAD) {
                lv_event_send(dsc->focused_obj, code, lv_indev_get_act());
            }
        }
    }
}

static lv_obj_t * find_chid(lv_obj_t * obj, lv_obj_t * start_child, find_mode_t mode)
{
    lv_coord_t x_start = get_x_center(start_child);
    lv_coord_t y_start = get_y_center(start_child);
    uint32_t child_cnt = lv_obj_get_child_cnt(obj);
    lv_obj_t * guess = NULL;
    lv_coord_t x_err_guess = LV_COORD_MAX;
    lv_coord_t y_err_guess = LV_COORD_MAX;
    lv_coord_t h_half = lv_obj_get_height(start_child) / 2;
    lv_coord_t h_max = lv_obj_get_height(obj) + lv_obj_get_scroll_top(obj) + lv_obj_get_scroll_bottom(obj);
    uint32_t i;
    for(i = 0; i < child_cnt; i++) {
        lv_obj_t * child = lv_obj_get_child(obj, i);
        if(child == start_child) continue;
        if(obj_is_focuable(child) == false) continue;

        lv_coord_t x_err = 0;
        lv_coord_t y_err = 0;
        switch(mode) {
            case FIND_LEFT:
                x_err = get_x_center(child) - x_start;
                y_err = get_y_center(child) - y_start;
                if(x_err >= 0) continue;    /*It's on the right*/
                if(LV_ABS(y_err) > h_half) continue;    /*Too far*/
                break;
            case FIND_RIGHT:
                x_err = get_x_center(child) - x_start;
                y_err = get_y_center(child) - y_start;
                if(x_err <= 0) continue;    /*It's on the left*/
                if(LV_ABS(y_err) > h_half) continue;    /*Too far*/
                break;
            case FIND_TOP:
                x_err = get_x_center(child) - x_start;
                y_err = get_y_center(child) - y_start;
                if(y_err >= 0) continue;    /*It's on the bottom*/
                break;
            case FIND_BOTTOM:
                x_err = get_x_center(child) - x_start;
                y_err = get_y_center(child) - y_start;
                if(y_err <= 0) continue;    /*It's on the top*/
                break;
            case FIND_NEXT_ROW_FIRST_ITEM:
                y_err = get_y_center(child) - y_start;
                if(y_err <= 0) continue;    /*It's on the top*/
                x_err = lv_obj_get_x(child);
                break;
            case FIND_PREV_ROW_LAST_ITEM:
                y_err = get_y_center(child) - y_start;
                if(y_err >= 0) continue;    /*It's on the bottom*/
                x_err = obj->coords.x2 - child->coords.x2;
                break;
            case FIND_FIRST_ROW:
                x_err = get_x_center(child) - x_start;
                y_err = lv_obj_get_y(child);
                break;
            case FIND_LAST_ROW:
                x_err = get_x_center(child) - x_start;
                y_err = h_max - lv_obj_get_y(child);
        }

        if(guess == NULL ||
           (y_err * y_err + x_err * x_err < y_err_guess * y_err_guess + x_err_guess * x_err_guess)) {
            guess = child;
            x_err_guess  = x_err;
            y_err_guess  = y_err;
        }
    }
    return guess;
}

static lv_obj_t * find_first_focusable(lv_obj_t * obj)
{
    uint32_t child_cnt = lv_obj_get_child_cnt(obj);
    uint32_t i;
    for(i = 0; i < child_cnt; i++) {
        lv_obj_t * child = lv_obj_get_child(obj, i);
        if(obj_is_focuable(child)) return child;

    }
    return NULL;
}

static lv_obj_t * find_last_focusable(lv_obj_t * obj)
{
    uint32_t child_cnt = lv_obj_get_child_cnt(obj);
    int32_t i;
    for(i = child_cnt - 1; i >= 0; i--) {
        lv_obj_t * child = lv_obj_get_child(obj, i);
        if(obj_is_focuable(child)) return child;
    }
    return NULL;
}

static bool obj_is_focuable(lv_obj_t * obj)
{
    if(lv_obj_has_flag(obj, LV_OBJ_FLAG_HIDDEN)) return false;
    if(lv_obj_has_flag(obj, LV_OBJ_FLAG_CLICKABLE | LV_OBJ_FLAG_CLICK_FOCUSABLE)) return true;
    else return false;
}

static lv_coord_t get_x_center(lv_obj_t * obj)
{
    return obj->coords.x1 + lv_area_get_width(&obj->coords) / 2;
}

static lv_coord_t get_y_center(lv_obj_t * obj)
{
    return obj->coords.y1 + lv_area_get_height(&obj->coords) / 2;
}

#endif /*LV_USE_GRIDNAV*/
