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

#define BUFFER_SIZE 100
#define FILE_HEADER_STRING "__info2_image_file_format__"


static int controlFile(FILE *file) {
    if (file == NULL) {
        return 0;
    }
    char buffer[BUFFER_SIZE];
    fread(buffer, sizeof(char), strlen(FILE_HEADER_STRING), file);
    buffer[strlen(FILE_HEADER_STRING)] = '\0';
    return !strcmp(FILE_HEADER_STRING, buffer);
}

static unsigned int readNumber(FILE *file) {
    unsigned int number = 0;
    fread(&number, sizeof(unsigned short), 1, file);
    return number;
}


// fillBuffer und readLabel muss immer in einer Schleife zusammen stehen
static int fillBuffer(unsigned char buffer[], unsigned int bufferSize, FILE *file) {
        int readcount = fread(buffer, sizeof(GrayScalePixelType), bufferSize, file);
        if (readcount == 0)
            return 0;
    return 1;
}

static void readLabels(FILE *file, unsigned char label[], unsigned int count) {
    fread(label + count, sizeof(char), 1, file);
}


GrayScaleImageSeries *readImages(const char *path) {
    FILE *file = fopen(path, "rb");

    if (!controlFile(file)) {
        return NULL;
    }
    GrayScaleImageSeries *firstSeries = malloc(sizeof(GrayScaleImageSeries));
    firstSeries ->count = readNumber(file);
    unsigned int width = readNumber(file);
    unsigned int height = readNumber(file);

    firstSeries ->labels = malloc(firstSeries ->count*sizeof(unsigned char));
    firstSeries ->images = malloc(firstSeries ->count*sizeof(GrayScaleImage));
    firstSeries ->addrSourceTxt = file;
    if (firstSeries ->labels == NULL || firstSeries ->images == NULL) {
        return NULL;
    }
    int fault = 1;
    unsigned int const bufferSize = width * height;
    for (unsigned int i = 0; i < firstSeries ->count && fault; i++)
    {
        GrayScaleImage *grayScaleImage = &firstSeries ->images[i];
        grayScaleImage ->buffer = malloc(width * height*sizeof(GrayScalePixelType));
        grayScaleImage ->width = width;
        grayScaleImage -> height = height;
        if (width == 0 || height == 0 || firstSeries ->count == 0) { // prüfen ob eingabe richtig ist
            return NULL;
        }

        fault = fillBuffer(grayScaleImage ->buffer, bufferSize, file);
        readLabels(file, firstSeries ->labels, i);
    }

    return firstSeries;
}


void clearSeries(GrayScaleImageSeries *series) {
    if (series == NULL) {return;}
    if (series->images != NULL) {
        for (unsigned int i = 0; i < series->count; i++) {
            const GrayScaleImage image = series->images[i];
            if (image.buffer != NULL) {
                free(image.buffer);
            }
        }
        free(series->images);
    }
    if (series->labels != NULL) {
        free(series->labels);
    }
    fclose(series->addrSourceTxt);
    free(series);
}