#include "../../include/mgui/list.h"
#include "../../include/alloc.h"
#include <mgl/window/window.h>
#include <assert.h>

/*
    TODO: Optimize for lists with 2 items or less by setting |items| and |items_capacity| to the first and second item
    if num_items <= 2.
*/

mgui_list* mgui_list_create(mgui_list_direction direction) {
    mgui_list *list = mgui_alloc(sizeof(mgui_list));    
    mgui_widget_init(&list->widget, MGUI_WIDGET_LIST);
    list->direction = direction;
    list->position = (mgl_vec2i){ 0, 0 };
    list->background_color = (mgl_color){ 0, 0, 0, 0 };
    list->items = NULL;
    list->items_capacity = 0;
    list->num_items = 0;
    return list;
}

void mgui_list_destroy(mgui_list *list) {
    for(size_t i = 0; i < list->num_items; ++i) {
        mgui_widget_destroy(list->items[i]);
    }
    mgui_free(list->items);
    mgui_free(list);
}

mgui_widget* mgui_list_to_widget(mgui_list *list) {
    return &list->widget;
}

mgui_list* mgui_widget_to_list(mgui_widget *widget) {
    assert(widget->type == MGUI_WIDGET_LIST);
    return (mgui_list*)widget;
}

void mgui_list_set_position(mgui_list *self, mgl_vec2i position) {
    self->position = position;
}

void mgui_list_set_width(mgui_list *self, int width) {
    /* TODO: if direction is horizontal then put the widget in the center of its area */
    /* TODO: put the widget in the center for vertical as well, for items with a max size */
    /* TODO: support max size for widgets */
    if(self->direction == MGUI_LIST_VERTICAL) {
        for(size_t i = 0; i < self->num_items; ++i) {
            mgui_widget_set_width(self->items[i], width);
        }
    }
}

void mgui_list_set_background_color(mgui_list *self, mgl_color color) {
    self->background_color = color;
}

static void mgui_list_ensure_capacity(mgui_list *self, size_t new_capacity) {
    if(self->items_capacity >= new_capacity)
        return;

    size_t capacity = self->items_capacity;
    if(capacity == 0)
        capacity = 8;

    while(capacity < new_capacity) {
        capacity = capacity + (capacity >> 1); /* capacity *= 1.5 */
    }

    self->items = mgui_realloc(self->items, capacity);
    self->items_capacity = capacity;
}

void mgui_list_append(mgui_list *self, mgui_widget *widget) {
    mgui_list_ensure_capacity(self, (self->num_items + 1) * sizeof(mgui_widget*));
    self->items[self->num_items] = widget;
    ++self->num_items;
}

void mgui_list_on_event(mgui_list *self, mgl_window *window, mgl_event *event) {
    for(size_t i = 0; i < self->num_items; ++i) {
        mgui_widget_on_event(self->items[i], window, event);
    }
}

static int max_int(int a, int b) {
    return a >= b ? a : b;
}

/* TODO: Check if visible in scissor */

mgl_vec2i mgui_list_draw(mgui_list *self, mgl_window *window) {
    mgl_vec2i position = self->position;
    /* TODO: */
    mgl_vec2i size = (mgl_vec2i){ 0, 0 };

    /* TODO:
    if(self->background_color.a > 0) {
        mgl_rectangle rect = {
            .position = { self->position.x, self->position.y },
            .size = { self->size.x, self->size.y },
            .color = self->background_color
        };
        mgl_rectangle_draw(mgl_get_context(), &rect);
    }
    */

    /* TODO: Set scissor for each draw widget */

    switch(self->direction) {
        case MGUI_LIST_HORIZONITAL: {
            for(size_t i = 0; i < self->num_items; ++i) {
                mgui_widget_set_position(self->items[i], position);
                const mgl_vec2i widget_size = mgui_widget_draw(self->items[i], window);
                size.x += widget_size.x;
                size.y = max_int(size.y, widget_size.y);
                position.x += widget_size.x;
            }
            break;
        }
        case MGUI_LIST_VERTICAL: {
            for(size_t i = 0; i < self->num_items; ++i) {
                mgui_widget_set_position(self->items[i], position);
                const mgl_vec2i widget_size = mgui_widget_draw(self->items[i], window);
                size.x = max_int(size.x, widget_size.x);
                size.y += widget_size.y;
                position.y += widget_size.y;
            }
            break;
        }
    }

    return size;
}