/*
 * Screenshot support for OmniNX Installer Payload
 * Based on TegraExplorer (AllgemeinerProblemLoeser) TakeScreenshot implementation.
 */

#include "screenshot.h"
#include "gfx.h"
#include "nx_sd.h"
#include <libs/fatfs/ff.h>
#include <mem/heap.h>
#include <display/di.h>
#include <utils/util.h>
#include <utils/sprintf.h>
#include <rtc/max77620-rtc.h>
#include <string.h>

/* BMP file header (54 bytes), matching TegraExplorer tools.h */
typedef struct __attribute__((packed)) _bmp_hdr_t
{
	u16 magic;
	u32 size;
	u32 rsvd;
	u32 data_off;
	u32 hdr_size;
	u32 width;
	u32 height;
	u16 planes;
	u16 pxl_bits;
	u32 comp;
	u32 img_size;
	u32 res_h;
	u32 res_v;
	u64 rsvd2;
} bmp_hdr_t;

#define BMP_HEADER_SIZE  0x36
#define FB_SIZE          0x384000   /* 1280 * 720 * 4 */
#define SCREEN_W         1280
#define SCREEN_H         720

void take_screenshot(void)
{
	static u32 last_timer = 0;

	if (!sd_get_card_mounted())
		return;

	/* 3-second cooldown (same as TegraExplorer) */
	u32 now = get_tmr_s();
	if (last_timer != 0 && now < last_timer + 3)
		return;
	last_timer = now;

	const char basepath[] = "sd:/switch/screenshot";
	char name[48];
	char path[80];
	rtc_time_t rtc;

	max77620_rtc_get_time(&rtc);
	s_printf(name, "omninx_installer_%04d%02d%02d_%02d%02d%02d.bmp",
		(u32)rtc.year, (u32)rtc.month, (u32)rtc.day,
		(u32)rtc.hour, (u32)rtc.min, (u32)rtc.sec);
	s_printf(path, "%s/%s", basepath, name);

	f_mkdir("sd:/switch");
	f_mkdir(basepath);

	const u32 file_size = BMP_HEADER_SIZE + FB_SIZE;
	u8 *bitmap = (u8 *)malloc(file_size);
	u32 *fb_copy = (u32 *)malloc(FB_SIZE);
	if (!bitmap || !fb_copy) {
		if (bitmap) free(bitmap);
		if (fb_copy) free(fb_copy);
		return;
	}

	/* Copy framebuffer with same coordinate flip as TegraExplorer (BGR layout) */
	u32 *fb_ptr = gfx_ctxt.fb;
	for (int x = SCREEN_W - 1; x >= 0; x--) {
		for (int y = SCREEN_H - 1; y >= 0; y--)
			fb_copy[y * SCREEN_W + x] = *fb_ptr++;
	}

	memcpy(bitmap + BMP_HEADER_SIZE, fb_copy, FB_SIZE);

	bmp_hdr_t *bmp = (bmp_hdr_t *)bitmap;
	bmp->magic    = 0x4D42;
	bmp->size     = file_size;
	bmp->rsvd     = 0;
	bmp->data_off = BMP_HEADER_SIZE;
	bmp->hdr_size = 40;
	bmp->width    = SCREEN_W;
	bmp->height   = SCREEN_H;
	bmp->planes   = 1;
	bmp->pxl_bits = 32;
	bmp->comp     = 0;
	bmp->img_size = FB_SIZE;
	bmp->res_h    = 2834;
	bmp->res_v    = 2834;
	bmp->rsvd2    = 0;

	sd_save_to_file(bitmap, file_size, path);

	free(bitmap);
	free(fb_copy);

	/* Brief backlight flash (same as TegraExplorer) */
	display_backlight_brightness(255, 1000);
	msleep(100);
	display_backlight_brightness(100, 1000);
}