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

#define COMMENT_LENGTH 256
#define COMMENT_ARRAY_SIZE 10
#define MAX_PIXEL_HEIGHT 480
#define MAX_PIXEL_WIDTH 640

struct PPM {
    char format[2 + 1]; //2 letter code for PPM format, +1 for 2 spaces
    char comments[COMMENT_LENGTH + 1][COMMENT_ARRAY_SIZE]; //comment array - n+1 size array to store n values
    int width; //number of columns
    int height; //number of rows
    int max; //maximum colour value (usually 255)
    int rgbPixels[MAX_PIXEL_WIDTH * MAX_PIXEL_HEIGHT][3]; //integers between 0 and max for pixel i's RGB values
}PPM;

struct PPM * getPPM(FILE *fd);

void showPPM(struct PPM *i);

int main(int argc, char **argv) {
    FILE *file = fopen("ape.ppm", "r");
    if(file == NULL) return 0;
    else {
        struct PPM *newPPM = getPPM(file);

        if(newPPM == NULL) return 1;

        printf("\n");

        showPPM(newPPM);

        return 0;
    }
}

struct PPM * getPPM(FILE *fd) {
    if(fd == NULL) {
        return NULL;
    }

    struct PPM *newPPMFile = /*(PPM *)*/ malloc(sizeof(PPM)); //casting result of malloc can potentially mask errors and is unnecessary

    fscanf(fd, "%2s\n", newPPMFile->format);
    //printf("%2s\n", newPPMFile->format);

    //check for comments
    int i = 0;
    while(i < COMMENT_ARRAY_SIZE && fscanf(fd, "# %79[^\n] \n", newPPMFile->comments[i]) == 1) {
        //printf("%s\n", newPPMFile->comments[i]);
        i++;
    }

    //read width and height
    //fscanf(fd, "%d %d", &newPPMFile->width, &newPPMFile->height);
    if (fscanf(fd, "%d %d", &newPPMFile->width, &newPPMFile->height) != 2) {
        //printf("%s\n", "Error reading width & height\n");
        return NULL;
    }
    //printf("%d %d\n", newPPMFile->width, newPPMFile->height);

    //read max
    if(fscanf(fd, "%d", &newPPMFile->max) != 1) {
        //printf("%s\n", "Error reading max\n");
        return NULL;
    }
    //printf("%d\n", newPPMFile->max);

    //read rgb data in rgb array
    int counter = 0;
    while(counter < (MAX_PIXEL_HEIGHT * MAX_PIXEL_WIDTH) &&
          fscanf(fd, "%d\n%d\n%d\n", &newPPMFile->rgbPixels[counter][0], &newPPMFile->rgbPixels[counter][1], &newPPMFile->rgbPixels[counter][2]) != EOF) {
        //printf("%d %d %d\n", newPPMFile->rgbPixels[counter][0], newPPMFile->rgbPixels[counter][1], newPPMFile->rgbPixels[counter][2]);
        counter++;
    }

    //close file
    fclose(fd);

    //free unused memory??
    //free(newPPMFile);

    return newPPMFile;
}

void showPPM(struct PPM *i) {
    printf("%s\n", i->format);

    //print comments array
    int x;
    for(x = 0; x < sizeof(i->comments) / sizeof(i->comments[0]); x++) {
        printf("# %s\n", i->comments[x]);
    }

    printf("%d %d\n", i->width, i->height);
    printf("%d\n", i->max);

    //print rgb values
    for(x = 0; x < 500; x++) {
        printf("%d %d %d\n", i->rgbPixels[x][0], i->rgbPixels[x][1], i->rgbPixels[x][2]);
    }
}