/* 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 source tree.
 *
 * 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.
 */

//usage:#define fbsplash_trivial_usage
//usage:       "-s IMGFILE [-c] [-d DEV] [-i INIFILE] [-f CMD]"
//usage:#define fbsplash_full_usage "\n\n"
//usage:       "        -s      Image"
//usage:     "\n        -c      Hide cursor"
//usage:     "\n        -d      Framebuffer device (default /dev/fb0)"
//usage:     "\n        -i      Config file (var=value):"
//usage:     "\n                        BAR_LEFT,BAR_TOP,BAR_WIDTH,BAR_HEIGHT"
//usage:     "\n                        BAR_R,BAR_G,BAR_B"
//usage:     "\n        -f      Control pipe (else exit after drawing image)"
//usage:     "\n                        commands: 'NN' (% for progress bar) or 'exit'"

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

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

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;
        unsigned bytes_per_pixel;
        // cached (8 - scr_var.COLOR.length):
        unsigned red_shift;
        unsigned green_shift;
        unsigned blue_shift;
};
#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

/**
 * Configure palette for RGB:332
 */
static void fb_setpal(int fd)
{
        struct fb_cmap cmap;
        /* fb colors are 16 bit */
        unsigned short red[256], green[256], blue[256];
        unsigned i;

        /* RGB:332 */
        for (i = 0; i < 256; i++) {
                /* Color is encoded in pixel value as rrrgggbb.
                 * 3-bit color is mapped to 16-bit one as:
                 * 000 -> 00000000 00000000
                 * 001 -> 00100100 10010010
                 * ...
                 * 011 -> 01101101 10110110
                 * 100 -> 10010010 01001001
                 * ...
                 * 111 -> 11111111 11111111
                 */
                red[i]   = (( i >> 5       ) * 0x9249) >> 2; // rrr * 00 10010010 01001001 >> 2
                green[i] = (((i >> 2) & 0x7) * 0x9249) >> 2; // ggg * 00 10010010 01001001 >> 2
                /* 2-bit color is easier: */
                blue[i]  =  ( i       & 0x3) * 0x5555; // bb * 01010101 01010101
        }

        cmap.start = 0;
        cmap.len   = 256;
        cmap.red   = red;
        cmap.green = green;
        cmap.blue  = blue;
        cmap.transp = 0;

        xioctl(fd, FBIOPUTCMAP, &cmap);
}

/**
 * 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);

        switch (G.scr_var.bits_per_pixel) {
        case 8:
                fb_setpal(fbfd);
                break;

        case 16:
        case 24:
        case 32:
                break;

        default:
                bb_error_msg_and_die("unsupported %u bpp", (int)G.scr_var.bits_per_pixel);
                break;
        }

        G.red_shift   = 8 - G.scr_var.red.length;
        G.green_shift = 8 - G.scr_var.green.length;
        G.blue_shift  = 8 - G.scr_var.blue.length;
        G.bytes_per_pixel = (G.scr_var.bits_per_pixel + 7) >> 3;

        // map the device in memory
        G.addr = mmap(NULL,
                        G.scr_var.yres * G.scr_fix.line_length,
                        PROT_WRITE, MAP_SHARED, fbfd, 0);
        if (G.addr == MAP_FAILED)
                bb_perror_msg_and_die("mmap");

        // point to the start of the visible screen
        G.addr += G.scr_var.yoffset * G.scr_fix.line_length + G.scr_var.xoffset * G.bytes_per_pixel;
        close(fbfd);
}


/**
 * Return pixel value of the passed RGB color.
 * This is performance critical fn.
 */
static unsigned fb_pixel_value(unsigned r, unsigned g, unsigned b)
{
        /* We assume that the r,g,b values are <= 255 */

        if (G.bytes_per_pixel == 1) {
                r = r        & 0xe0; // 3-bit red
                g = (g >> 3) & 0x1c; // 3-bit green
                b =  b >> 6;         // 2-bit blue
                return r + g + b;
        }
        if (G.bytes_per_pixel == 2) {
                // ARM PL110 on Integrator/CP has RGBA5551 bit arrangement.
                // We want to support bit locations like that.
                //
                // First shift out unused bits
                r = r >> G.red_shift;
                g = g >> G.green_shift;
                b = b >> G.blue_shift;
                // Then shift the remaining bits to their offset
                return (r << G.scr_var.red.offset) +
                        (g << G.scr_var.green.offset) +
                        (b << G.scr_var.blue.offset);
        }
        // RGB 888
        return b + (g << 8) + (r << 16);
}

/**
 * Draw pixel on framebuffer
 */
static void fb_write_pixel(unsigned char *addr, unsigned pixel)
{
        switch (G.bytes_per_pixel) {
        case 1:
                *addr = pixel;
                break;
        case 2:
                *(uint16_t *)addr = pixel;
                break;
        case 4:
                *(uint32_t *)addr = pixel;
                break;
        default: // 24 bits per pixel
                addr[0] = pixel;
                addr[1] = pixel >> 8;
                addr[2] = pixel >> 16;
        }
}


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

        thispix = fb_pixel_value(nred, ngreen, nblue);

        // horizontal lines
        ptr1 = G.addr + G.nbar_posy * G.scr_fix.line_length + G.nbar_posx * G.bytes_per_pixel;
        ptr2 = G.addr + (G.nbar_posy + G.nbar_height - 1) * G.scr_fix.line_length + G.nbar_posx * G.bytes_per_pixel;
        cnt = G.nbar_width - 1;
        do {
                fb_write_pixel(ptr1, thispix);
                fb_write_pixel(ptr2, thispix);
                ptr1 += G.bytes_per_pixel;
                ptr2 += G.bytes_per_pixel;
        } while (--cnt >= 0);

        // vertical lines
        ptr1 = G.addr + G.nbar_posy * G.scr_fix.line_length + G.nbar_posx * G.bytes_per_pixel;
        ptr2 = G.addr + G.nbar_posy * G.scr_fix.line_length + (G.nbar_posx + G.nbar_width - 1) * G.bytes_per_pixel;
        cnt = G.nbar_height - 1;
        do {
                fb_write_pixel(ptr1, thispix);
                fb_write_pixel(ptr2, thispix);
                ptr1 += G.scr_fix.line_length;
                ptr2 += G.scr_fix.line_length;
        } 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;
        unsigned thispix;
        unsigned char *ptr;

        thispix = fb_pixel_value(nred, ngreen, nblue);

        cnt1 = ny2pos - ny1pos;
        nypos = ny1pos;
        do {
                ptr = G.addr + nypos * G.scr_fix.line_length + nx1pos * G.bytes_per_pixel;
                cnt2 = nx2pos - nx1pos;
                do {
                        fb_write_pixel(ptr, thispix);
                        ptr += G.bytes_per_pixel;
                } 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 left_x, top_y, pos_x;
        unsigned 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 ((int)(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 ((int)(height | width) < 0)
                return;

        pos_x = left_x;
        if (percent > 0) {
                int i, y;

                // actual progress bar
                pos_x += (unsigned)(width * percent) / 100;

                y = top_y;
                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 + (unsigned)i*100 / height;
                        fb_drawfullrectangle(
                                        left_x, y, pos_x, y,
                                        gray_level, gray_level, gray_level);
                        y++;
                        i--;
                }
        }

        fb_drawfullrectangle(
                        pos_x, top_y,
                        left_x + width, top_y + height,
                        G.nbar_colr, G.nbar_colg, G.nbar_colb);
}


/**
 * Draw image from PPM file
 */
static void fb_drawimage(void)
{
        FILE *theme_file;
        char *read_ptr;
        unsigned char *pixline;
        unsigned i, j, width, height, line_size;

        if (LONE_DASH(G.image_filename)) {
                theme_file = stdin;
        } else {
                int fd = open_zipped(G.image_filename);
                if (fd < 0)
                        bb_simple_perror_msg_and_die(G.image_filename);
                theme_file = xfdopen_for_read(fd);
        }

        /* Parse ppm header:
         * - Magic: two characters "P6".
         * - Whitespace (blanks, TABs, CRs, LFs).
         * - A width, formatted as ASCII characters in decimal.
         * - Whitespace.
         * - A height, ASCII decimal.
         * - Whitespace.
         * - The maximum color value, ASCII decimal, in 0..65535
         * - Newline or other single whitespace character.
         *   (we support newline only)
         * - A raster of Width * Height pixels in triplets of rgb
         *   in pure binary by 1 or 2 bytes. (we support only 1 byte)
         */
#define concat_buf bb_common_bufsiz1
        read_ptr = concat_buf;
        while (1) {
                int w, h, max_color_val;
                int rem = concat_buf + sizeof(concat_buf) - read_ptr;
                if (rem < 2
                 || fgets(read_ptr, rem, theme_file) == NULL
                ) {
                        bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);
                }
                read_ptr = strchrnul(read_ptr, '#');
                *read_ptr = '\0'; /* ignore #comments */
                if (sscanf(concat_buf, "P6 %u %u %u", &w, &h, &max_color_val) == 3
                 && max_color_val <= 255
                ) {
                        width = w; /* w is on stack, width may be in register */
                        height = h;
                        break;
                }
        }

        line_size = width*3;
        pixline = xmalloc(line_size);

        if (width > G.scr_var.xres)
                width = G.scr_var.xres;
        if (height > G.scr_var.yres)
                height = G.scr_var.yres;
        for (j = 0; j < height; j++) {
                unsigned char *pixel;
                unsigned char *src;

                if (fread(pixline, 1, line_size, theme_file) != line_size)
                        bb_error_msg_and_die("bad PPM file '%s'", G.image_filename);
                pixel = pixline;
                src = G.addr + j * G.scr_fix.line_length;
                for (i = 0; i < width; i++) {
                        unsigned thispix = fb_pixel_value(pixel[0], pixel[1], pixel[2]);
                        fb_write_pixel(src, thispix);
                        src += G.bytes_per_pixel;
                        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 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_positive(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, "\033[?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
                        DEBUG_MESSAGE(itoa(num));
#endif
                        fb_drawprogressbar(num);
                }
                free(num_buf);
        }

        if (bCursorOff) // restore cursor
                full_write(STDOUT_FILENO, "\033[?25h", 6);

        return EXIT_SUCCESS;
}