/* vi: set sw=4 ts=4: */
/*
 * Copyright (C) 2008 Michele Sanges <michele.sanges@gmail.com>
 *
 * 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 ns[7];         // n-parameters
        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)

#define nbar_width      ns[0]   // progress bar width
#define nbar_height     ns[1]   // progress bar height
#define nbar_posx       ns[2]   // progress bar horizontal position
#define nbar_posy       ns[3]   // progress bar vertical position
#define nbar_colr       ns[4]   // progress bar color red component
#define nbar_colg       ns[5]   // progress bar color green component
#define nbar_colb       ns[6]   // progress bar color blue component

#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("mmap");
        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_height - 1 /* HUH?!  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, *ptr;
        FILE *theme_file;
        unsigned char *pixline;
        unsigned i, j, width, height, line_size;

        theme_file = xfopen_stdin(G.image_filename);
        head = xmalloc(256);

        /* parse ppm header
         * - A ppm image’s magic number is the two characters "P6".
         * - Whitespace (blanks, TABs, CRs, LFs).
         * - A width, formatted as ASCII characters in decimal.
         * - Whitespace.
         * - A height, again in ASCII decimal.
         * - Whitespace.
         * - The maximum color value (Maxval), again in ASCII decimal. Must be
         *   less than 65536.
         * - Newline or other single whitespace character.
         * - A raster of Width * Height pixels in triplets of rgb
         *   in pure binary by 1 (or not implemented 2) bytes.
         */
        while (1) {
                if (fgets(head, 256, theme_file) == NULL
                        /* do not overrun the buffer */
                        || strlen(bb_common_bufsiz1) >= sizeof(bb_common_bufsiz1) - 256)
                        bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);

                ptr = memchr(skip_whitespace(head), '#', 256);
                if (ptr != NULL)
                        *ptr = 0; /* ignore comments */
                strcat(bb_common_bufsiz1, head);
                // width, height, max_color_val
                if (sscanf(bb_common_bufsiz1, "P6 %u %u %u", &width, &height, &i) == 3
                        && i <= 255)
                        break;
                /* If we do not find a signature throughout the whole file then
                   we will diagnose this via EOF on read in the head of the loop.  */
        }

        if (ENABLE_FEATURE_CLEAN_UP)
                free(head);
        if (width != G.scr_var.xres || height != G.scr_var.yres)
                bb_error_msg_and_die("PPM %dx%d does not match screen %dx%d",
                                                         width, height, G.scr_var.xres, G.scr_var.yres);
        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;
                }
        }
        if (ENABLE_FEATURE_CLEAN_UP)
                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_WIDTH\0" "BAR_HEIGHT\0"
                "BAR_LEFT\0" "BAR_TOP\0"
                "BAR_R\0" "BAR_G\0" "BAR_B\0"
#if DEBUG
                "DEBUG\0"
#endif
                ;
        char *token[2];
        parser_t *parser = config_open2(cfg_filename, xfopen_stdin);
        while (config_read(parser, token, 2, 2, "#=",
                                    (PARSE_NORMAL | PARSE_MIN_DIE) & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
                unsigned val = xatoi_u(token[1]);
                int i = index_in_strings(param_names, token[0]);
                if (i < 0)
                        bb_error_msg_and_die("syntax error: %s", token[0]);
                if (i >= 0 && i < 7)
                        G.ns[i] = val;
#if DEBUG
                if (i == 7) {
                        G.bdebug_messages = val;
                        if (G.bdebug_messages)
                                G.logfile_fd = xfopen_for_write("/tmp/fbsplash.log");
                }
#endif
        }
        config_close(parser);
}


int fbsplash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fbsplash_main(int argc UNUSED_PARAM, 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;
}