/*
 *  libpipi       Proper image processing implementation library
 *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
 *                All Rights Reserved
 *
 *  $Id$
 *
 *  This library is free software. It comes without any warranty, to
 *  the extent permitted by applicable law. You can redistribute it
 *  and/or modify it under the terms of the Do What The Fuck You Want
 *  To Public License, Version 2, as published by Sam Hocevar. See
 *  http://sam.zoy.org/wtfpl/COPYING for more details.
 */

/*
 * oric.c: Oric Atmos import/export functions
 */

#include "config.h"
#include "common.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "pipi.h"
#include "pipi_internals.h"

static int load_data(const char *name, uint8_t *screen);

pipi_image_t *pipi_load_oric(const char *name)
{
    static uint8_t const pal[32] =
    {
        0x00, 0x00, 0x00, 0xff,
        0x00, 0x00, 0xff, 0xff,
        0x00, 0xff, 0x00, 0xff,
        0x00, 0xff, 0xff, 0xff,
        0xff, 0x00, 0x00, 0xff,
        0xff, 0x00, 0xff, 0xff,
        0xff, 0xff, 0x00, 0xff,
        0xff, 0xff, 0xff, 0xff,
    };

    uint8_t screen[8000];
    pipi_image_t *img;
    pipi_pixels_t *p;
    uint8_t *data;
    int x, y, i;

    if(load_data(name, screen) < 0)
        return NULL;

    img = pipi_new(240, 200);
    p = pipi_getpixels(img, PIPI_PIXELS_RGBA_C);
    data = p->pixels;

    for(y = 0; y < 200; y++)
    {
        int bg = 0, fg = 7;

        for(x = 0; x < 40; x++)
        {
            int col;
            uint8_t c = screen[y * 40 + x];

            if(c & 0x40)
            {
                for(i = 0; i < 6; i++)
                {
                    col = (c & (1 << (5 - i))) ? (c & 0x80) ? 7 - fg : fg
                                               : (c & 0x80) ? 7 - bg : bg;
                    memcpy(data + (y * 240 + x * 6 + i) * 4, pal + 4 * col, 4);
                }
            }
            else if((c & 0x60) == 0x00)
            {
                if(c & 0x10)
                    bg = c & 0x7;
                else
                    fg = c & 0x7;

                col = (c & 0x80) ? 7 - bg : bg;

                for(i = 0; i < 6; i++)
                    memcpy(data + (y * 240 + x * 6 + i) * 4, pal + 4 * col, 4);
            }
            /* else: invalid sequence */
        }
    }

    img->codec_priv = NULL;

    img->wrap = 0;
    img->u8 = 1;

    return img;
}

int pipi_save_oric(pipi_image_t *img, const char *name)
{
    return -1;
}

/*
 * XXX: The following functions are local.
 */

static int load_data(const char *name, uint8_t *screen)
{
    FILE *fp;
    int ch;

    fp = fopen(name, "r");
    if(!fp)
        return -1;

    /* Skip the sync bytes */
    ch = fgetc(fp);
    if(ch != 0x16)
        goto syntax_error;
    while((ch = fgetc(fp)) == 0x16)
        ;
    if(ch != 0x24)
        goto syntax_error;

    /* Skip the header */
    if(fgetc(fp) != 0x00 || fgetc(fp) != 0xff || fgetc(fp) != 0x80
        || fgetc(fp) != 0x00 || fgetc(fp) != 0xbf || fgetc(fp) != 0x3f
        || fgetc(fp) != 0xa0 || fgetc(fp) != 0x00 || fgetc(fp) != 0x00)
        goto syntax_error;

    /* Skip the file name */
    for(;;)
    {
        ch = fgetc(fp);
        if(ch == EOF)
            goto syntax_error;
        if(ch == 0x00)
            break;
    }

    /* Read screen data */
    if(fread(screen, 1, 8000, fp) != 8000)
        goto syntax_error;

    fclose(fp);
    return 0;

syntax_error:
    fclose(fp);
    return -1;
}