#include "logic/page_render.h"

#include <stdio.h>
#include <string.h>

#include "logic/bitmap_format.h"
#include "logic/builtin_fonts.h"

static Font usableFont(PageResources &resources, const char *name)
{
	Font font = resources.font(name);
	if (validFont(font.data, font.size) && font.scale >= 1)
		return font;
	return builtinFont(*findBuiltinFont(FONT_NORMAL_NAME));
}

static void clearBox(uint8_t *bitmap, int x, int y, int width, int height)
{
	for (int yy = y; yy < y + height; yy++)
		for (int xx = x; xx < x + width; xx++)
			setBitmapPixel(bitmap, xx, yy, false);
}

// The earlier of two "next change" times (0 = none)
static uint32_t sooner(uint32_t a, uint32_t b)
{
	if (a == 0)
		return b;
	if (b == 0)
		return a;
	return a < b ? a : b;
}

// Image: a bitmap drawn with its top left corner at x, y. With an entity the name is the
// element's text followed by the state, or followed by "default" when there is no bitmap
// for the state.
static void drawImage(const PageElement &e, PageResources &resources, uint8_t *bitmap, ElementBox &box)
{
	uint8_t image[BITMAP_BYTES];
	bool found;
	if (e.entity[0])
	{
		char name[64];
		const char *state = resources.haValue(e);
		snprintf(name, sizeof(name), "%s%s", e.text, state ? state : "");
		found = state && resources.background(name, image);
		if (!found)
		{
			snprintf(name, sizeof(name), "%sdefault", e.text);
			found = resources.background(name, image);
		}
	}
	else
		found = resources.background(e.text, image);

	box = ElementBox();
	box.x = e.x;
	box.y = e.y;
	if (!found)
		return;

	// The box of its dots
	int left = BITMAP_WIDTH, right = -1, top = BITMAP_HEIGHT, bottom = -1;
	for (int y = 0; y < BITMAP_HEIGHT; y++)
		for (int x = 0; x < BITMAP_WIDTH; x++)
			if (bitmapPixel(image, x, y))
			{
				left = x < left ? x : left;
				right = x > right ? x : right;
				top = y < top ? y : top;
				bottom = y > bottom ? y : bottom;
			}
	if (right < 0)
		return;
	box.x = e.x + left;
	box.y = e.y + top;
	box.width = right - left + 1;
	box.height = bottom - top + 1;

	if (e.overlay == Overlay::Box)
		clearBox(bitmap, box.x - 1, box.y - 1, box.width + 2, box.height + 2);
	for (int y = top; y <= bottom; y++)
		for (int x = left; x <= right; x++)
			if (bitmapPixel(image, x, y))
			{
				int bx = e.x + x, by = e.y + y;
				bool on = e.overlay == Overlay::Invert ? !bitmapPixel(bitmap, bx, by) : true;
				setBitmapPixel(bitmap, bx, by, on);
			}
}

// A text element; returns the ms until it scrolls on (0: it doesn't scroll)
static uint32_t drawTextElement(const PageElement &e, const char *text, uint32_t now_ms, PageResources &resources,
								uint8_t *bitmap, ElementBox &box)
{
	Font font = usableFont(resources, e.font);
	int width = textWidth(font, text), height = fontHeight(font);
	DrawMode mode = e.overlay == Overlay::Invert ? DrawMode::Invert : DrawMode::Set;
	// Without scrolling the element is as wide as its text, otherwise the window
	int area = e.scroll_width ? e.scroll_width : width;
	int left = e.x;
	if (e.align == Align::Center)
		left -= area / 2;
	else if (e.align == Align::Right)
		left -= area;

	box.x = left;
	box.y = e.y;
	box.width = area;
	box.height = height;
	if (e.overlay == Overlay::Box)
		clearBox(bitmap, left - 1, e.y - 1, area + 2, height + 2);

	if (width <= area)
	{
		// Fits: aligned in the window like the element
		int x = left;
		if (e.align == Align::Center)
			x += (area - width) / 2;
		else if (e.align == Align::Right)
			x += area - width;
		drawText(bitmap, font, x, e.y, text, mode);
		return 0;
	}

	// Scrolls from right to left, the next round follows after SCROLL_GAP dots
	uint32_t period = width + SCROLL_GAP;
	uint64_t steps = (uint64_t)now_ms * e.scroll_speed / 1000;
	int offset = (int)(steps % period);
	drawText(bitmap, font, left - offset, e.y, text, mode, left, left + area);
	drawText(bitmap, font, left - offset + (int)period, e.y, text, mode, left, left + area);
	// Until the next step
	uint64_t next_step_ms = ((steps + 1) * 1000 + e.scroll_speed - 1) / e.scroll_speed;
	uint32_t wait = (uint32_t)(next_step_ms - now_ms);
	return wait ? wait : 1;
}

uint32_t renderPage(const DynamicPage &page, const LocalTime &time, uint32_t now_ms, PageResources &resources,
					uint8_t *bitmap, ElementBox *boxes)
{
	memset(bitmap, 0, BITMAP_BYTES);
	const PageSlot *slot = activeSlot(page, time.hour * 60 + time.minute);
	if (slot && slot->bitmap[0] && !resources.background(slot->bitmap, bitmap))
		memset(bitmap, 0, BITMAP_BYTES);

	uint32_t next = 0;
	bool running = resources.stopwatchRunning();
	uint32_t stopwatch_ms = resources.stopwatchMs();
	for (int i = 0; i < page.element_count && i < PAGE_ELEMENTS; i++)
	{
		const PageElement &e = page.elements[i];
		ElementBox box;
		if (e.type == ElementType::Image)
			drawImage(e, resources, bitmap, box);
		else
		{
			ElementValues values;
			if (e.type == ElementType::HaValue)
				values.ha_value = resources.haValue(e);
			values.stopwatch_ms = stopwatch_ms;
			char text[80];
			elementText(e, time, values, text, sizeof(text));
			next = sooner(next, drawTextElement(e, text, now_ms, resources, bitmap, box));

			if (elementShowsSeconds(e, time, running)) // the stopwatch's seconds count from its start
				next = sooner(next, e.type == ElementType::Stopwatch ? 1000 - stopwatch_ms % 1000
																	  : 1000 - (time.millisecond % 1000));
			else if (e.type == ElementType::Stopwatch && running) // H:MM: the next stopwatch minute
				next = sooner(next, 60000 - stopwatch_ms % 60000);
		}
		if (boxes)
			boxes[i] = box;
	}
	return next;
}