/* vi: set sw=4 ts=4: */
/*
 * Copyright (C) 2008 Michele Sanges <michele.sanges@otomelara.it>,
 * <michele.sanges@gmail.it>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * Usage:
 * - use kernel option 'vga=xxx' or otherwise enable framebuffer device.
 * - put somewhere fbsplash.cfg file and an image in .ppm format.
 * - run applet: $ setsid fbsplash [params] &
 *      -c: hide cursor
 *      -d /dev/fbN: framebuffer device (if not /dev/fb0)
 *      -s path_to_image_file (can be "-" for stdin)
 *      -i path_to_cfg_file
 *      -f path_to_fifo (can be "-" for stdin)
 * - if you want to run it only in presence of a kernel parameter
 *   (for example fbsplash=on), use:
 *   grep -q "fbsplash=on" </proc/cmdline && setsid fbsplash [params]
 * - commands for fifo:
 *   "NN" (ASCII decimal number) - percentage to show on progress bar.
 *   "exit" (or just close fifo) - well you guessed it.
 */

#include "libbb.h"
#include <linux/fb.h>

/* If you want logging messages on /tmp/fbsplash.log... */
#define DEBUG 0

#define BYTES_PER_PIXEL 2

typedef unsigned short DATA;

struct globals {
#if DEBUG
	bool bdebug_messages;	// enable/disable logging
	FILE *logfile_fd;	// log file
#endif
	unsigned char *addr;	// pointer to framebuffer memory
	unsigned nbar_width;	// progress bar width
	unsigned nbar_height;	// progress bar height
	unsigned nbar_posx;	// progress bar horizontal position
	unsigned nbar_posy;	// progress bar vertical position
	unsigned char nbar_colr;	// progress bar color red component
	unsigned char nbar_colg;	// progress bar color green component
	unsigned char nbar_colb;	// progress bar color blue component
	const char *image_filename;
	struct fb_var_screeninfo scr_var;
	struct fb_fix_screeninfo scr_fix;
};
#define G (*ptr_to_globals)
#define INIT_G() \
	do { \
		SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
	} while (0)


#if DEBUG
#define DEBUG_MESSAGE(strMessage, args...) \
	if (G.bdebug_messages) { \
		fprintf(G.logfile_fd, "[%s][%s] - %s\n", \
		__FILE__, __FUNCTION__, strMessage);	\
	}
#else
#define DEBUG_MESSAGE(...) ((void)0)
#endif


/**
 *	Open and initialize the framebuffer device
 * \param *strfb_device pointer to framebuffer device
 */
static void fb_open(const char *strfb_device)
{
	int fbfd = xopen(strfb_device, O_RDWR);

	// framebuffer properties
	xioctl(fbfd, FBIOGET_VSCREENINFO, &G.scr_var);
	xioctl(fbfd, FBIOGET_FSCREENINFO, &G.scr_fix);

	if (G.scr_var.bits_per_pixel != 16)
		bb_error_msg_and_die("only 16 bpp is supported");

	// map the device in memory
	G.addr = mmap(NULL,
			G.scr_var.xres * G.scr_var.yres
			* BYTES_PER_PIXEL /*(G.scr_var.bits_per_pixel / 8)*/ ,
			PROT_WRITE, MAP_SHARED, fbfd, 0);
	if (G.addr == MAP_FAILED)
		bb_perror_msg_and_die("can't mmap %s", strfb_device);
	close(fbfd);
}


/**
 *	Draw hollow rectangle on framebuffer
 */
static void fb_drawrectangle(void)
{
	int cnt;
	DATA thispix;
	DATA *ptr1, *ptr2;
	unsigned char nred = G.nbar_colr/2;
	unsigned char ngreen =  G.nbar_colg/2;
	unsigned char nblue = G.nbar_colb/2;

	nred   >>= 3;  // 5-bit red
	ngreen >>= 2;  // 6-bit green
	nblue  >>= 3;  // 5-bit blue
	thispix = nblue + (ngreen << 5) + (nred << (5+6));

	// horizontal lines
	ptr1 = (DATA*)(G.addr + (G.nbar_posy * G.scr_var.xres + G.nbar_posx) * BYTES_PER_PIXEL);
	ptr2 = (DATA*)(G.addr + ((G.nbar_posy + G.nbar_height - 1) * G.scr_var.xres + G.nbar_posx) * BYTES_PER_PIXEL);
	cnt = G.nbar_width - 1;
	do {
		*ptr1++ = thispix;
		*ptr2++ = thispix;
	} while (--cnt >= 0);

	// vertical lines
	ptr1 = (DATA*)(G.addr + (G.nbar_posy * G.scr_var.xres + G.nbar_posx) * BYTES_PER_PIXEL);
	ptr2 = (DATA*)(G.addr + (G.nbar_posy * G.scr_var.xres + G.nbar_posx + G.nbar_width - 1) * BYTES_PER_PIXEL);
	cnt = G.nbar_posy + G.nbar_height - 1 - G.nbar_posy;
	do {
		*ptr1 = thispix; ptr1 += G.scr_var.xres;
		*ptr2 = thispix; ptr2 += G.scr_var.xres;
	} while (--cnt >= 0);
}


/**
 *	Draw filled rectangle on framebuffer
 * \param nx1pos,ny1pos upper left position
 * \param nx2pos,ny2pos down right position
 * \param nred,ngreen,nblue rgb color
 */
static void fb_drawfullrectangle(int nx1pos, int ny1pos, int nx2pos, int ny2pos,
	unsigned char nred, unsigned char ngreen, unsigned char nblue)
{
	int cnt1, cnt2, nypos;
	DATA thispix;
	DATA *ptr;

	nred   >>= 3;  // 5-bit red
	ngreen >>= 2;  // 6-bit green
	nblue  >>= 3;  // 5-bit blue
	thispix = nblue + (ngreen << 5) + (nred << (5+6));

	cnt1 = ny2pos - ny1pos;
	nypos = ny1pos;
	do {
		ptr = (DATA*)(G.addr + (nypos * G.scr_var.xres + nx1pos) * BYTES_PER_PIXEL);
		cnt2 = nx2pos - nx1pos;
		do {
			*ptr++ = thispix;
		} while (--cnt2 >= 0);

		nypos++;
	} while (--cnt1 >= 0);
}


/**
 *	Draw a progress bar on framebuffer
 * \param percent percentage of loading
 */
static void fb_drawprogressbar(unsigned percent)
{
	int i, left_x, top_y, width, height;

	// outer box
	left_x = G.nbar_posx;
	top_y = G.nbar_posy;
	width = G.nbar_width - 1;
	height = G.nbar_height - 1;
	if ((height | width) < 0)
		return;
	// NB: "width" of 1 actually makes rect with width of 2!
	fb_drawrectangle();

	// inner "empty" rectangle
	left_x++;
	top_y++;
	width -= 2;
	height -= 2;
	if ((height | width) < 0)
		return;
	fb_drawfullrectangle(
			left_x,	top_y,
					left_x + width, top_y + height,
			G.nbar_colr, G.nbar_colg, G.nbar_colb);

	if (percent > 0) {
		// actual progress bar
		width = width * percent / 100;
		i = height;
		if (height == 0)
			height++; // divide by 0 is bad
		while (i >= 0) {
			// draw one-line thick "rectangle"
			// top line will have gray lvl 200, bottom one 100
			unsigned gray_level = 100 + i*100/height;
			fb_drawfullrectangle(
					left_x, top_y, left_x + width, top_y,
					gray_level, gray_level, gray_level);
			top_y++;
			i--;
		}
	}
}


/**
 *	Draw image from PPM file
 */
static void fb_drawimage(void)
{
	char head[256];
	char s[80];
	FILE *theme_file;
	unsigned char *pixline;
	unsigned i, j, width, height, line_size;

	memset(head, 0, sizeof(head));
	theme_file = xfopen_stdin(G.image_filename);

	// parse ppm header
	while (1) {
		if (fgets(s, sizeof(s), theme_file) == NULL)
			bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);

		if (s[0] == '#')
			continue;

		if (strlen(head) + strlen(s) >= sizeof(head))
			bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);

		strcat(head, s);
		if (head[0] != 'P' || head[1] != '6')
			bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);

		// width, height, max_color_val
		if (sscanf(head, "P6 %u %u %u", &width, &height, &i) == 3)
			break;
// TODO: i must be <= 255!
	}

	line_size = width*3;
	if (width > G.scr_var.xres)
		width = G.scr_var.xres;
	if (height > G.scr_var.yres)
		height = G.scr_var.yres;

	pixline = xmalloc(line_size);
	for (j = 0; j < height; j++) {
		unsigned char *pixel = pixline;
		DATA *src = (DATA *)(G.addr + j * G.scr_fix.line_length);

		if (fread(pixline, 1, line_size, theme_file) != line_size)
			bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);
		for (i = 0; i < width; i++) {
			unsigned thispix;
			thispix = (((unsigned)pixel[0] << 8) & 0xf800)
				| (((unsigned)pixel[1] << 3) & 0x07e0)
				| (((unsigned)pixel[2] >> 3));
			*src++ = thispix;
			pixel += 3;
		}
	}
	free(pixline);
	fclose(theme_file);
}


/**
 *	Parse configuration file
 * \param *cfg_filename name of the configuration file
 */
static void init(const char *cfg_filename)
{
	static const char const param_names[] ALIGN1 =
		"BAR_LEFT\0" "BAR_TOP\0"
		"BAR_WIDTH\0" "BAR_HEIGHT\0"
		"BAR_R\0" "BAR_G\0" "BAR_B\0"
#if DEBUG
		"DEBUG\0"
#endif
		;

	FILE *inifile;
	char *buf;

	inifile = xfopen_stdin(cfg_filename);

	while ((buf = xmalloc_fgetline(inifile)) != NULL) {
		char *value_str;
		int val;

		if (*buf == '#') {  // it's a comment
			free(buf);
			continue;
		}

		value_str = strchr(buf, '=');
		if (!value_str)
			goto err;
		*value_str++ = '\0';
		val = xatoi_u(value_str);

		switch (index_in_strings(param_names, buf)) {
		case 0:
			// progress bar horizontal position
			G.nbar_posx = val;
			break;
		case 1:
			// progress bar vertical position
			G.nbar_posy = val;
			break;
		case 2:
			// progress bar width
			G.nbar_width = val;
			break;
		case 3:
			// progress bar height
			G.nbar_height = val;
			break;
		case 4:
			// progress bar color - red component
			G.nbar_colr = val;
			break;
		case 5:
			// progress bar color - green component
			G.nbar_colg = val;
			break;
		case 6:
			// progress bar color - blue component
			G.nbar_colb = val;
			break;
#if DEBUG
		case 7:
			G.bdebug_messages = val;
			if (G.bdebug_messages)
				G.logfile_fd = xfopen("/tmp/fbsplash.log", "w");
			break;
#endif
 err:
		default:
			bb_error_msg_and_die("syntax error: '%s'", buf);
		}
		free(buf);
	}
	fclose(inifile);
}


int fbsplash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fbsplash_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
	const char *fb_device, *cfg_filename, *fifo_filename;
	FILE *fp = fp; // for compiler
	char *num_buf;
	unsigned num;
	bool bCursorOff;

	INIT_G();

	// parse command line options
	fb_device = "/dev/fb0";
	cfg_filename = NULL;
	fifo_filename = NULL;
	bCursorOff = 1 & getopt32(argv, "cs:d:i:f:",
			&G.image_filename, &fb_device, &cfg_filename, &fifo_filename);

	// parse configuration file
	if (cfg_filename)
		init(cfg_filename);

	// We must have -s IMG
	if (!G.image_filename)
		bb_show_usage();

	fb_open(fb_device);

	if (fifo_filename && bCursorOff) {
		// hide cursor (BEFORE any fb ops)
		full_write(STDOUT_FILENO, "\x1b" "[?25l", 6);
	}

	fb_drawimage();

	if (!fifo_filename)
		return EXIT_SUCCESS;

	fp = xfopen_stdin(fifo_filename);
	if (fp != stdin) {
		// For named pipes, we want to support this:
		//  mkfifo cmd_pipe
		//  fbsplash -f cmd_pipe .... &
		//  ...
		//  echo 33 >cmd_pipe
		//  ...
		//  echo 66 >cmd_pipe
		// This means that we don't want fbsplash to get EOF
		// when last writer closes input end.
		// The simplest way is to open fifo for writing too
		// and become an additional writer :)
		open(fifo_filename, O_WRONLY); // errors are ignored
	}

	fb_drawprogressbar(0);
	// Block on read, waiting for some input.
	// Use of <stdio.h> style I/O allows to correctly
	// handle a case when we have many buffered lines
	// already in the pipe
	while ((num_buf = xmalloc_fgetline(fp)) != NULL) {
		if (strncmp(num_buf, "exit", 4) == 0) {
			DEBUG_MESSAGE("exit");
			break;
		}
		num = atoi(num_buf);
		if (isdigit(num_buf[0]) && (num <= 100)) {
#if DEBUG
			char strVal[10];
			sprintf(strVal, "%d", num);
			DEBUG_MESSAGE(strVal);
#endif
			fb_drawprogressbar(num);
		}
		free(num_buf);
	}

	if (bCursorOff) // restore cursor
		full_write(STDOUT_FILENO, "\x1b" "[?25h", 6);

	return EXIT_SUCCESS;
}