#include <malloc.h>
#include <graphics/bitmaps.h>
#include <sys/param.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <liquid/input_event.h>

#include "liquid.h"
#include "graphics/drawing.h"
#include "graphics/display_spec.h"

#include "scene_menu.h"

#if 0
static void paint(struct MenuScene *self)
{
    LCD_clearDisplay(0);

    int row = 0;
    for (int i = self->scroll_up; i < MIN(self->items_len, self->scroll_up + self->visible_lines); i++, row++) {
        bool selected = self->selected==i;
        LCD_setStrEx(self->items[i].label, 0, row * 8, selected?WHITE:BLACK,FONT_NORMAL|(selected?FONT_BG:0));
    }
}
#endif

#define HSCROLL_START_MS 750
#define HSCROLL_MS 250

static void paint(struct MenuScene *self)
{
    LCD_setRect(self->x, self->y, self->x + self->ncols*6, self->y + self->nlines*9, 1, WHITE);

    int row = 0;
    for (int i = self->scroll_up; i < MIN(self->items_len, self->scroll_up + self->nlines); i++, row++) {
        bool selected = self->selected==i;
        if (selected) LCD_setRect(self->x, self->y + row*9, self->x + self->ncols*6, self->y + row*9 + 8, 1, 1);
        size_t shift = 0;
        if (selected) {
            size_t len = utf8_strlen(self->items[i].label);
            shift = self->hscroll;
            if (shift > len - self->ncols) {
                shift = len - self->ncols;
            }
        }
        LCD_setStrEx(self->items[i].label, self->x + 1, self->y + row * 9 + 1, !selected, (struct TextStyle) {
            .bg = selected,
            .nowrap = 1,
            .skip = shift,
        });
    }
}

static struct SceneEvent onInput(struct MenuScene *self, struct InputEvent event) {
    switch (event.kind) {
        case InputEventKind_Wheel:;
            self->selected += event.wheel.direction;
            if (self->selected < 0) {
                self->selected = 0;
            }
            else if (self->selected >= self->items_len) {
                self->selected = self->items_len - 1;
            }

            // hacky scroll adjust
            while (self->selected - self->scroll_up < 1 && self->scroll_up > 0) {
                self->scroll_up--;
            }

            while (self->selected - self->scroll_up >= (self->nlines - 1) &&
                self->scroll_up < self->items_len - self->nlines) {
                self->scroll_up++;
            }

            // reset hscroll
            self->hscroll_cnt = 0;
            self->hscroll = 0;

            return SceneEvent_Repaint();

        case InputEventKind_Button:
            if (event.button.state) {
                if (self->onSelect) {
                    return self->onSelect(self);
                }
                return SceneEvent_Close(0, NULL);
            }
            // fall through
        default:
            return SceneEvent_None();
    }
}

static struct SceneEvent onTick(struct MenuScene *self, uint32_t millis) {
    size_t len = utf8_strlen(self->items[self->selected].label);
    self->hscroll_cnt += millis;

    if (len > self->ncols) {
        size_t limit = (self->hscroll == 0 ? HSCROLL_START_MS : HSCROLL_MS);

        if (self->hscroll_cnt >= limit) {
            self->hscroll_cnt -= limit;
            self->hscroll++;

            if (self->hscroll > len - self->ncols + 2/* trailing delay */) {
                self->hscroll = 0;
            }

            return SceneEvent_Repaint();
        }
    } else {
        self->hscroll = 0;

        // ensure periodic repaint (for parent)
        if (self->hscroll_cnt > 20) {
            return SceneEvent_Repaint();
        }
    }

    return SceneEvent_None();
}

static void deinit(struct MenuScene *self)
{
    free(self->items);
    self->items = NULL;

    if (self->extra_deinit) {
        self->extra_deinit((struct Scene *) self);
        self->extra = NULL;
    }
}

struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len) {
    struct MenuScene *scene = calloc(1, sizeof(struct MenuScene));

    scene->base.paint = (Scene_paint_t) paint;
    scene->base.onInput = (Scene_onInput_t) onInput;
    scene->base.deinit = (Scene_deinit_t) deinit;
    scene->base.onTick = (Scene_onTick_t) onTick;

    // onChildReturn is free to set by subclass

    // TODO long selected label scrolling on tick

    scene->items = items;
    scene->items_len = items_len;

    scene->nlines = 5;
    scene->ncols = 14;
    scene->x = 0;
    scene->y = 0;

    return scene;
}