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

struct User
{
    int id;
    int age;
    char name[25];
    char surname[30];
    float growth;
    float weight;
};

void randomUser(struct User* user, int id);

int main(int argc, char *argv[])
{

    srand(time(NULL));

	int npes;
	int myrank;
	double start, end;
    
    MPI_Init(&argc, &argv);

	
    int size, tempSize;
    MPI_Pack_size(2, MPI_INT, MPI_COMM_WORLD, &tempSize);
    size += tempSize;
    MPI_Pack_size(25, MPI_CHAR, MPI_COMM_WORLD, &tempSize);
    size += tempSize;
    MPI_Pack_size(30, MPI_CHAR, MPI_COMM_WORLD, &tempSize);
    size += tempSize;
    MPI_Pack_size(2, MPI_FLOAT, MPI_COMM_WORLD, &tempSize);
    size += tempSize;

    char *buffor = malloc(500*size); 

	start = MPI_Wtime();
	MPI_Comm_size(MPI_COMM_WORLD, &npes);
	MPI_Comm_rank(MPI_COMM_WORLD, &myrank);

	if (myrank == 0) {
        
        int position = 0;
        struct User users[500];

        for(int i = 0; i < 500; i++) {
            randomUser(&users[i], i);
            MPI_Pack(&users[i].id, 1, MPI_INT, buffor, 500*size, &position, MPI_COMM_WORLD);
            MPI_Pack(&users[i].age, 1, MPI_INT, buffor, 500*size, &position, MPI_COMM_WORLD);
            MPI_Pack(&users[i].name, 1, MPI_CHAR, buffor, 500*size, &position, MPI_COMM_WORLD);
            MPI_Pack(&users[i].surname, 1, MPI_CHAR, buffor, 500*size, &position, MPI_COMM_WORLD);
            MPI_Pack(&users[i].growth, 1, MPI_FLOAT, buffor, 500*size, &position, MPI_COMM_WORLD);
            MPI_Pack(&users[i].weight, 1, MPI_FLOAT, buffor, 500*size, &position, MPI_COMM_WORLD);
        }
        MPI_Send(buffor, position, MPI_PACKED, 1, 13, MPI_COMM_WORLD);
    	
	} else if (myrank == 1) {
        MPI_Status status;
        int position = 0;
        MPI_Recv(buffor, 500*size, MPI_PACKED, 0, 13, MPI_COMM_WORLD, &status);
        struct User users[500];
        for(int i =0; i < 500; i++) {
            MPI_Unpack(buffor, 500*size, &position, &(users[i].age), 1, MPI_INT, MPI_COMM_WORLD);
            printf("ID: %d\n", users[i].age);
        }
        
        // printf("%s", users[1].name);
            // printf("Process 1 received user info from process 0:\nid: %d\nage: %d\nname: %s\nsurname: %s\ngrowth: %.2f\nweight: %.1f\n --------------------------- \n",
            //                                                 users[i].id, users[i].age, users[i].name, users[i].surname, users[i].growth, users[i].weight);
        
		
		
	}

	end = MPI_Wtime();
	MPI_Finalize();

	if (myrank == 0) {
		printf("end of process %lf\n", end-start);
	}
	return 0;
}

void randomUser(struct User* user, int id) {
    user->id = id;
    user->age = (rand() % 30) + 18;

    int nameLength = (rand() % 21) + 5;
    for(int i = 0; i < nameLength; i++) {
        user->name[i] = 'a' + (rand() % 26);
    }
    user->name[nameLength] = 0;

    int surnameLength = (rand() % 26) + 5;
    for(int i = 0; i < nameLength; i++) {
        user->surname[i] = 'a' + (rand() % 26);
    }
    user->surname[surnameLength] = 0;
    user->growth = (2.0 - 1.3) * (rand() / (double)RAND_MAX) + 1.3;
    user->weight = (120.0 - 40.0) * (rand() / (double)RAND_MAX) + 40.0;
}