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

#define BUFFER_SIZE 100
#define FILE_HEADER_STRING "__info2_image_file_format__"



// TODO Implementieren Sie geeignete Hilfsfunktionen für das Lesen der Bildserie aus einer Datei

// TODO Vervollständigen Sie die Funktion readImages unter Benutzung Ihrer Hilfsfunktionen
GrayScaleImageSeries *readImages(const char *path)
{
    FILE* file = fopen(path, "rb");
    
    if(file == NULL) 
    {
        puts("could not open file.");

        return NULL;
    }

    if(!checkFileHeaderString(file))
    {
        puts("wrong File.");

        return NULL;
    }

    unsigned short count = getCount(file);
    if(!count)
    {
        puts("could not read number of images.");

        return NULL;
    }

    unsigned short width = getWidth(file);
    if(!width)
    {
        puts("could not read Width of images.");

        return NULL;
    }

    unsigned short height = getHeight(file);
    if(!height)
    {
        puts("could not read height of images.");

        return NULL;
    }

    GrayScaleImageSeries *series = createSeries(count);

    series->count = count;
    unsigned short resolution = width * height;

    for(unsigned int i = 0; i < series->count; i++)
    {
        series->images[i].width = width;
        series->images[i].height = height;

        series->images[i].buffer = getPixels(file, resolution);
        series->labels[i] = getLabel(file);
    }

    fclose(file);
    
    return series;
}



// TODO Vervollständigen Sie die Funktion clearSeries, welche eine Bildserie vollständig aus dem Speicher freigibt
void clearSeries(GrayScaleImageSeries *series)
{   
    for(int i = 0; i < series->count; i++)
    {
        free(series->images[i].buffer);
    }

    free(series->images);
    free(series->labels);
    free(series);
}


int checkFileHeaderString(FILE *file)
{
    char buffer[strlen(FILE_HEADER_STRING)];

    fread(buffer, sizeof(char), strlen(FILE_HEADER_STRING), file);

    for(int i = 0; i < strlen(FILE_HEADER_STRING); i++)
    {
        if(buffer[i] != FILE_HEADER_STRING[i])
        {
            return 0;
        }
    }
    return 1;
}

unsigned short getCount(FILE *file)
{
    unsigned short count = 0;

    fread(&count, sizeof(unsigned short), 1, file);

    return count;
}

unsigned short getWidth(FILE *file)
{
    unsigned short width = 0;

    fread(&width, sizeof(unsigned short), 1, file);

    return width;
}

unsigned short getHeight(FILE *file)
{
    unsigned short height = 0;

    fread(&height, sizeof(unsigned short), 1, file);

    return height;
}

GrayScaleImageSeries *createSeries(unsigned short count)
{
    GrayScaleImage *images = (GrayScaleImage*) calloc(count, sizeof(GrayScaleImage));
    unsigned char *labels = (unsigned char*) calloc(count, sizeof(unsigned char));

    GrayScaleImageSeries *series = (GrayScaleImageSeries*) calloc(1, sizeof(GrayScaleImageSeries));
    series->images = images;
    series->labels = labels;

    return series;
}

GrayScalePixelType *getPixels(FILE *file, unsigned short resolution)
{
    GrayScalePixelType *pixels = (GrayScalePixelType*) calloc(resolution, sizeof(GrayScalePixelType));

    fread(pixels, sizeof(GrayScalePixelType), resolution, file);

    return pixels;
}

unsigned char getLabel(FILE *file)
{
    unsigned char label = '\0';

    fread(&label, sizeof(unsigned char), 1, file);

    return label;
}