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

typedef struct {
    char red;
    char green;
    char blue;
} rgb;
typedef struct {
    int width;
    int height;
    int maxval;
    int type;
    rgb **pixels;
    char **gray;
} image;

void readInput(FILE *input, image *in) {
    char *readBuffer;
    fscanf(input, "%c %c", &readBuffer[0], readBuffer[1]);
    in->type = atoi(readBuffer[1]);
    fscanf(input, "%d %d", in->width, in->height);
    fscanf(input, "%d", in->maxval);
    if (in->type == 2) {
        for (int i = 0; i < in->height; ++i) {
            fread(in->gray[i], sizeof(char), in->width, input);
        }
    }
    if (in->type == 3) {
        for (int i = 0; i < in->height; ++i) {
            fread(in->pixels[i], sizeof(rgb), in->width, input);
        }
    }
}

void processImage(image *img, int rank, int nrProcesses) {
    if (rank == 0) {
        for (int i = 0; i < img->height; ++i) {
            if (img->type == 2) {
                MPI_Recv(img->gray[i], img->width, MPI_CHAR, )
            }
        }
        for (int x = 1; x < processes; ++x) {
            for (int j = x; j < output->height; j += processes) {
                if (input->type == COLOR) {
                    MPI_Recv(output->color_image[j], output->width * 3, MPI_CHAR, x, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
                } else {
                    MPI_Recv(output->gray_image[j], output->width, MPI_CHAR, x, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
                }
            }
        }
    }
    if (rank != 0) {
        for (int j = rank; j < output->height; j += processes) {
            if (input->type == COLOR) {
                MPI_Send(output->color_image[j], output->width * 3, MPI_CHAR, 0, 0, MPI_COMM_WORLD);
            } else {
                MPI_Send(output->gray_image[j], output->width, MPI_CHAR, 0, 0, MPI_COMM_WORLD);
            }
        }
    }
}

int main(int argc, char *argv[]) {
    int rank, nrProcesses;
    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &nrProcesses);
    MPI_Comm_rank(MPI_COMM_WORLD, rank);
    FILE *input, *output;
    image in, out;
    input = fopen(argv[1], "r");
    if (input == NULL) {
        return;
    }
    readInput(input, in);
    processImage(in, rank, nrProcesses);
    MPI_Finalize();
    return 0;
}