#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)
{
    GrayScaleImageSeries *series = NULL;

    FILE *file = fopen(path, "rb");

    if(file != NULL)
    {
        if(checkFileHeader(file))
        {
            unsigned int numberOfImages = readDimension(file);
            unsigned short int width = readDimension(file);
            unsigned short int height = readDimension(file);
            series = (GrayScaleImageSeries *)malloc(sizeof(GrayScaleImageSeries));
            series->images = (GrayScaleImage *)malloc(numberOfImages * sizeof(GrayScaleImage));
            series->labels = (unsigned char *)malloc(numberOfImages * sizeof(unsigned char));
            series->count = numberOfImages;
            for(unsigned int i = 0; i < numberOfImages; i++)
            {
                series->images[i] = readImage(file);
                series->labels[i] = readLabel(file);
            }
            fclose(file);
            return series;
        }
    }
    return series;
}


bool checkFileHeader(FILE *file)
{
    char buffer[BUFFER_SIZE] = {0};
    fread(buffer, sizeof(char), BUFFER_SIZE, file);
    return strcmp(buffer, FILE_HEADER_STRING) == 0;
}

unsigned short int readDimension(FILE *file)
{
    unsigned short int dimension = 0;
    fread(&dimension, sizeof(unsigned short int), 1, file);
    return dimension;
}

GrayScaleImage readImage(FILE *file)
{
    GrayScaleImage image;
    image.buffer = (GrayScalePixelType *)malloc(image.width * image.height * sizeof(GrayScalePixelType));
    fread(image.buffer, sizeof(GrayScalePixelType), image.width * image.height, file);
    return image;
}

unsigned char readLabel(FILE *file)
{
    unsigned char label = 0;
    fread(&label, sizeof(unsigned char), 1, file);
    return label;
}

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