#include "main.h"
#include "format-jpeg.h"

/*
 * Include file for users of JPEG library.
 * You will need to have included system headers that define at least
 * the typedefs FILE and size_t before you can include jpeglib.h.
 * (stdio.h is sufficient on ANSI-conforming systems.)
 * You may also wish to include "jerror.h".
 */

#include "jpeglib.h"

/*
 * <setjmp.h> is used for the optional error recovery mechanism shown in
 * the second part of the example.
 */

#include <setjmp.h>

/*
 * ERROR HANDLING:
 *
 * The JPEG library's standard error handler (jerror.c) is divided into
 * several "methods" which you can override individually.  This lets you
 * adjust the behavior without duplicating a lot of code, which you might
 * have to update with each future release.
 *
 * Our example here shows how to override the "error_exit" method so that
 * control is returned to the library's caller when a fatal error occurs,
 * rather than calling exit() as the standard error_exit method does.
 *
 * We use C's setjmp/longjmp facility to return control.  This means that the
 * routine which calls the JPEG library must first execute a setjmp() call to
 * establish the return point.  We want the replacement error_exit to do a
 * longjmp().  But we need to make the setjmp buffer accessible to the
 * error_exit routine.  To do this, we make a private extension of the
 * standard JPEG error handler object.  (If we were using C++, we'd say we
 * were making a subclass of the regular error handler.)
 *
 * Here's the extended error handler struct:
 */

struct my_error_mgr {
    struct jpeg_error_mgr pub; /* "public" fields */

    jmp_buf setjmp_buffer; /* for return to caller */
};

typedef struct my_error_mgr *my_error_ptr;

/*
 * Here's the routine that will replace the standard error_exit method:
 */

METHODDEF(void)
my_error_exit(j_common_ptr cinfo) {
    /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
    my_error_ptr myerr = (my_error_ptr)cinfo->err;

    /* Always display the message. */
    /* We could postpone this until after returning, if we chose. */
    (*cinfo->err->output_message)(cinfo);

    /* Return control to the setjmp point */
    longjmp(myerr->setjmp_buffer, 1);
}

BITMAP *load_jpeg(AL_CONST char *filename, RGB *pal) {
    /* This struct contains the JPEG decompression parameters and pointers to
     * working space (which is allocated as needed by the JPEG library).
     */
    struct jpeg_decompress_struct cinfo;
    /* We use our private extension JPEG error handler.
     * Note that this struct must live as long as the main JPEG parameter
     * struct, to avoid dangling-pointer problems.
     */
    struct my_error_mgr jerr;
    /* More stuff */
    FILE *infile;      /* source file */
    JSAMPARRAY buffer; /* Output row buffer */
    int row_stride;    /* physical row width in output buffer */

    /* In this example we want to open the input file before doing anything else,
     * so that the setjmp() error recovery below can assume the file is open.
     * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
     * requires it in order to read binary files.
     */

    if ((infile = fopen(filename, "rb")) == NULL) {
        DEBUGF("can't open %s\n", filename);
        return NULL;
    }

    /* Step 1: allocate and initialize JPEG decompression object */

    /* We set up the normal JPEG error routines, then override error_exit. */
    cinfo.err = jpeg_std_error(&jerr.pub);
    jerr.pub.error_exit = my_error_exit;
    /* Establish the setjmp return context for my_error_exit to use. */
    if (setjmp(jerr.setjmp_buffer)) {
        /* If we get here, the JPEG code has signaled an error.
         * We need to clean up the JPEG object, close the input file, and return.
         */
        jpeg_destroy_decompress(&cinfo);
        fclose(infile);
        return NULL;
    }
    /* Now we can initialize the JPEG decompression object. */
    jpeg_create_decompress(&cinfo);

    /* Step 2: specify data source (eg, a file) */

    jpeg_stdio_src(&cinfo, infile);

    /* Step 3: read file parameters with jpeg_read_header() */

    (void)jpeg_read_header(&cinfo, TRUE);
    /* We can ignore the return value from jpeg_read_header since
     *   (a) suspension is not possible with the stdio data source, and
     *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
     * See libjpeg.txt for more info.
     */

    /* Step 4: set parameters for decompression */

    /* In this example, we don't need to change any of the defaults set by
     * jpeg_read_header(), so we do nothing here.
     */

    /* Step 5: Start decompressor */

    (void)jpeg_start_decompress(&cinfo);
    /* We can ignore the return value since suspension is not possible
     * with the stdio data source.
     */

    DEBUGF("JPEG has %dx%dx%d\n", cinfo.output_width, cinfo.output_height, cinfo.num_components);

    if ((cinfo.num_components != 1) && (cinfo.num_components != 3)) {
        DEBUGF("Wrong number of components: %d", cinfo.num_components);
        jpeg_destroy_decompress(&cinfo);
        fclose(infile);
        return NULL;
    }

    BITMAP *bm = create_bitmap_ex(32, cinfo.output_width, cinfo.output_height);
    if (!bm) {
        DEBUGF("Can't create bitmap: %s", allegro_error);
        jpeg_destroy_decompress(&cinfo);
        fclose(infile);
        return NULL;
    }

    /* We may need to do some setup of our own at this point before reading
     * the data.  After jpeg_start_decompress() we have the correct scaled
     * output image dimensions available, as well as the output colormap
     * if we asked for color quantization.
     * In this example, we need to make an output work buffer of the right size.
     */
    /* JSAMPLEs per row in output buffer */
    row_stride = cinfo.output_width * cinfo.output_components;
    /* Make a one-row-high sample array that will go away when done with image */
    buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo, JPOOL_IMAGE, row_stride, 1);

    /* Step 6: while (scan lines remain to be read) */
    /*           jpeg_read_scanlines(...); */

    /* Here we use the library's state variable cinfo.output_scanline as the
     * loop counter, so that we don't have to keep track ourselves.
     */
    while (cinfo.output_scanline < cinfo.output_height) {
        /* jpeg_read_scanlines expects an array of pointers to scanlines.
         * Here the array is only one element long, but you could ask for
         * more than one scanline at a time if that's more convenient.
         */
        int numread = jpeg_read_scanlines(&cinfo, buffer, 1);
        (void)numread;
        // DEBUGF("num read = %d, current = %d\n", numread, cinfo.output_scanline);
        /* Assume put_scanline_someplace wants a pointer and sample count. */
        // put_scanline_someplace(buffer[0], row_stride);

        for (int x = 0; x < cinfo.output_width; x++) {
            unsigned int xIdx = x * cinfo.output_components;
            if (cinfo.num_components == 1) {
                bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_r_shift_32 / 8] = bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_g_shift_32 / 8] =
                    bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_b_shift_32 / 8] = buffer[0][xIdx];
            } else {
                bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_r_shift_32 / 8] = buffer[0][0 + xIdx];
                bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_g_shift_32 / 8] = buffer[0][1 + xIdx];
                bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_b_shift_32 / 8] = buffer[0][2 + xIdx];
            }
            bm->line[cinfo.output_scanline - 1][x * 4 + _rgb_a_shift_32 / 8] = 0xFF;
        }
    }

    /* Step 7: Finish decompression */

    (void)jpeg_finish_decompress(&cinfo);
    /* We can ignore the return value since suspension is not possible
     * with the stdio data source.
     */

    /* Step 8: Release JPEG decompression object */

    /* This is an important step since it will release a good deal of memory. */
    jpeg_destroy_decompress(&cinfo);

    /* After finish_decompress, we can close the input file.
     * Here we postpone it until after no more JPEG errors are possible,
     * so as to simplify the setjmp error logic above.  (Actually, I don't
     * think that jpeg_destroy can do an error exit, but why assume anything...)
     */
    fclose(infile);

    /* At this point you may want to check to see whether any corrupt-data
     * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
     */

    /* And we're done! */
    return bm;
}

int save_jpeg(AL_CONST char *filename, BITMAP *bm, AL_CONST RGB *pal) {
    const int NUM_COMPONENTS = 3;

    /* This struct contains the JPEG compression parameters and pointers to
     * working space (which is allocated as needed by the JPEG library).
     * It is possible to have several such structures, representing multiple
     * compression/decompression processes, in existence at once.  We refer
     * to any one struct (and its associated working data) as a "JPEG object".
     */
    struct jpeg_compress_struct cinfo;
    /* This struct represents a JPEG error handler.  It is declared separately
     * because applications often want to supply a specialized error handler
     * (see the second half of this file for an example).  But here we just
     * take the easy way out and use the standard error handler, which will
     * print a message on stderr and call exit() if compression fails.
     * Note that this struct must live as long as the main JPEG parameter
     * struct, to avoid dangling-pointer problems.
     */
    struct jpeg_error_mgr jerr;
    /* More stuff */
    FILE *outfile;           /* target file */
    JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */
    int row_stride;          /* physical row width in image buffer */

    /* Step 1: allocate and initialize JPEG compression object */

    /* We have to set up the error handler first, in case the initialization
     * step fails.  (Unlikely, but it could happen if you are out of memory.)
     * This routine fills in the contents of struct jerr, and returns jerr's
     * address which we place into the link field in cinfo.
     */
    cinfo.err = jpeg_std_error(&jerr);
    /* Now we can initialize the JPEG compression object. */
    jpeg_create_compress(&cinfo);

    /* Step 2: specify data destination (eg, a file) */
    /* Note: steps 2 and 3 can be done in either order. */

    /* Here we use the library-supplied code to send compressed data to a
     * stdio stream.  You can also write your own code to do something else.
     * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
     * requires it in order to write binary files.
     */
    if ((outfile = fopen(filename, "wb")) == NULL) {
        DEBUGF("can't open %s\n", filename);
        return -1;
    }
    jpeg_stdio_dest(&cinfo, outfile);

    /* Step 3: set parameters for compression */

    /* First we supply a description of the input image.
     * Four fields of the cinfo struct must be filled in:
     */
    cinfo.image_width = bm->w; /* image width and height, in pixels */
    cinfo.image_height = bm->h;
    cinfo.input_components = NUM_COMPONENTS; /* # of color components per pixel */
    cinfo.in_color_space = JCS_RGB;          /* colorspace of input image */
    /* Now use the library's routine to set default compression parameters.
     * (You must set at least cinfo.in_color_space before calling this,
     * since the defaults depend on the source color space.)
     */
    jpeg_set_defaults(&cinfo);
    /* Now you can set any non-default parameters you wish to.
     * Here we just illustrate the use of quality (quantization table) scaling:
     */
    jpeg_set_quality(&cinfo, output_quality, TRUE /* limit to baseline-JPEG values */);

    /* Step 4: Start compressor */

    /* TRUE ensures that we will write a complete interchange-JPEG file.
     * Pass TRUE unless you are very sure of what you're doing.
     */
    jpeg_start_compress(&cinfo, TRUE);

    /* Step 5: while (scan lines remain to be written) */
    /*           jpeg_write_scanlines(...); */

    /* Here we use the library's state variable cinfo.next_scanline as the
     * loop counter, so that we don't have to keep track ourselves.
     * To keep things simple, we pass one scanline per call; you can pass
     * more if you wish, though.
     */
    row_stride = bm->w * NUM_COMPONENTS; /* JSAMPLEs per row in image_buffer */

    uint8_t *rgba = malloc(row_stride * NUM_COMPONENTS);
    if (!rgba) {
        fclose(outfile);
        jpeg_destroy_compress(&cinfo);
        return -1;
    }

    while (cinfo.next_scanline < cinfo.image_height) {
        /* jpeg_write_scanlines expects an array of pointers to scanlines.
         * Here the array is only one element long, but you could pass
         * more than one scanline at a time if that's more convenient.
         */
        uint8_t *ptr = rgba;
        int y = cinfo.next_scanline;
        for (int x = 0; x < bm->w; x++) {
            uint32_t argb = getpixel(bm, x, y);
            uint8_t r = (argb >> 16) & 0xFF;
            uint8_t g = (argb >> 8) & 0xFF;
            uint8_t b = argb & 0xFF;

            *ptr++ = r;
            *ptr++ = g;
            *ptr++ = b;
        }
        row_pointer[0] = rgba;
        (void)jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }

    /* Step 6: Finish compression */

    jpeg_finish_compress(&cinfo);
    /* After finish_compress, we can close the output file. */
    fclose(outfile);

    /* Step 7: release JPEG compression object */

    /* This is an important step since it will release a good deal of memory. */
    jpeg_destroy_compress(&cinfo);

    /* And we're done! */
    return 0;
}
