#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <errno.h>
#include "pnglite.h"

#include <cammy/sram.h>

static void usage(int argc, char **argv, const char *message, ...) {
    if (message) {
        va_list args;

        va_start(args, message);
        vfprintf(stderr, message, args);
        va_end(args);
         fprintf(stderr, "\n");
    }

    fprintf(stderr, "usage: %s file.sav frame1..30 photo.png\n", argv[0]);

    exit(1);
}

static uint8_t *buf_malloc(png_t *png) {
    return malloc(4 * png->width * png->height);
}

static void image_copy(cammy_sram_frame *frame, uint8_t *buf) {
    size_t x, y;

    memset(&frame->photo, '\0', sizeof(cammy_sram_photo));

    for (y=0; y<CAMMY_SRAM_PHOTO_HEIGHT; y++) {
        for (x=0; x<CAMMY_SRAM_PHOTO_WIDTH; x++) {
            uint8_t r = buf[4*CAMMY_SRAM_PHOTO_WIDTH*y+4*x],
                    g = buf[4*CAMMY_SRAM_PHOTO_WIDTH*y+4*x+1],
                    b = buf[4*CAMMY_SRAM_PHOTO_WIDTH*y+4*x+2];

            float avg = 255.0 - ((float)r + (float)g + (float)b) / 3;

            uint8_t value = (uint8_t)(avg / 64.0);

            cammy_sram_tile *tile = &frame->photo.tiles[y>>3][x>>3];

            int tile_x = x & 7,
                tile_y = y & 7;

            tile->data[2*tile_y]   |= ((value & 0x02) >> 1) << (7 - tile_x);
            tile->data[2*tile_y+1] |=  (value & 0x01)       << (7 - tile_x);
        }
    }
}

int main(int argc, char **argv) {
    cammy_sram *sram;
    png_t *png;
    int frame = 0;
    uint8_t *buf;

    int error;

    if (argc < 2) {
        usage(argc, argv, "No save file provided");
    } else if (argc < 3) {
        usage(argc, argv, "No frame number provided");
    } else if (argc < 4) {
        usage(argc, argv, "No photo provided");
    }

    frame = atoi(argv[2]);

    if (frame < 1 || frame > CAMMY_SRAM_FRAME_COUNT) {
        usage(argc, argv, "Invalid frame number");
    }

    if ((sram = cammy_sram_open(argv[1])) == NULL) {
        fprintf(stderr, "%s: %s: %s: %s\n",
            argv[0], "cammy_sram_open()", argv[1], strerror(errno));

        goto error_sram_open;
    }

    png_init(malloc, free);

    if ((png = malloc(sizeof(*png))) == NULL) {
        goto error_malloc_png;
    }

    if ((error = png_open_file_read(png, argv[3])) < 0) {
        fprintf(stderr, "%s: %s: %s: %s\n",
            argv[0], "png_open_file_read()", argv[3], png_error_string(error));

        goto error_png_open_file_read;
    }

    if (png->width  != CAMMY_SRAM_PHOTO_WIDTH
     || png->height != CAMMY_SRAM_PHOTO_HEIGHT) {
        fprintf(stderr, "%s: %s: %s\n",
            argv[0], argv[3], "Invalid image dimensions");

        goto error_invalid_dimensions;
    }

    if ((buf = buf_malloc(png)) == NULL) {
        fprintf(stderr, "%s: %s: %s\n",
            argv[0], "malloc()", strerror(errno));

        goto error_buf_malloc;
    }

    if ((error = png_get_data(png, buf)) < 0) {
        fprintf(stderr, "%s: %s: %s: %s\n",
            argv[0], "png_get_data()", argv[3], png_error_string(error));

        goto error_png_get_data;
    }

    image_copy(&sram->data->frames[frame], buf);

    free(buf);

    png_close_file(png);

    free(png);

    cammy_sram_close(sram);

    return 0;

error_png_get_data:
    free(buf);

error_buf_malloc:
error_invalid_dimensions:
    png_close_file(png);

error_png_open_file_read:
    free(png);

error_malloc_png:
    cammy_sram_close(sram);

error_sram_open:
    return 1;
}