#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;
    unsigned int readcount = fread(&number, sizeof(unsigned short), 1, file);
    if (readcount != 1) {
        return 0;
    }
    return number;
}
// TODO:alles in innere Funktion äußere Funktion nur fopen / fclose

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

static int readLabels(FILE *file, unsigned char label[], unsigned int count) {
    unsigned int readlabels = fread(label + count, sizeof(char), 1, file);
    if (readlabels == 0) {
        return 0;
    }
    return 1;
}


GrayScaleImageSeries *readImages(const char *path) {
    FILE *file = fopen(path, "rb");
    if (!controlFile(file)) {
        return NULL;
    }
    unsigned int count = readNumber(file);
    unsigned int width = readNumber(file);
    unsigned int height = readNumber(file);
    if (width == 0 || height == 0 || count == 0) {
        return NULL;
    }
    // Füllen des structs series
    GrayScaleImageSeries *series = malloc(sizeof(GrayScaleImageSeries));
    if (series == NULL) {
        return NULL;
    }

    series->count = count;
    series->labels = malloc(series->count * sizeof(unsigned char));
    series->images = malloc(series->count * sizeof(GrayScaleImage));
    series->addrSourceTxt = file;
    if (series->labels == NULL || series->images == NULL) {
        return NULL;
    }

    // struct grayScaleImage füllen als Teil eines Arrays innerhalb series
    unsigned int const bufferSize = width * height;
    for (unsigned int i = 0; i < series->count; i++) {

        GrayScaleImage *grayScaleImage = &series->images[i];
        grayScaleImage->buffer = calloc(bufferSize, width * height * sizeof(GrayScalePixelType));
        if (grayScaleImage->buffer == NULL) {
            return NULL;
        }

        grayScaleImage->width = width;
        grayScaleImage->height = height;
        int readBufferFault = fillBuffer(grayScaleImage->buffer, bufferSize, file);
        int readLabelFault = readLabels(file, series->labels, i);
        if (!readLabelFault || !readBufferFault) {
            return NULL;
        }
    }

    return series;
}


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);
}