#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>

#define STRING_MAX 32

struct etudiant {
  int id;
  char nom[STRING_MAX];
};

struct cours {
  int id;
  char nom[STRING_MAX];
};

struct note {
  int etudiant_id;
  int cours_id;
  int note;
};


void add_etudiant(char* name) {
  int fd = open("etudiants.dat", O_RDWR);
  int file_size=lseek(fd, 0, SEEK_END);
  int nb_etudiants = file_size/sizeof(struct etudiant);

  struct etudiant e;
  e.id = nb_etudiants;
  strncpy(e.nom, name, STRING_MAX);
  write(fd, &e, sizeof(struct etudiant));
  close(fd);
}


void add_cours(char* name) {
  int fd = open("cours.dat", O_RDWR);
  int file_size=lseek(fd, 0, SEEK_END);
  int nb_cours = file_size/sizeof(struct etudiant);

  struct cours c;
  c.id = nb_cours;
  strncpy(c.nom, name, STRING_MAX);
  write(fd, &c, sizeof(struct cours));
  close(fd);
}

void add_note(int etudiant_id, int cours_id, int note) {
  int fd = open("notes.dat", O_RDWR);
  struct note n;
  n.etudiant_id = etudiant_id;
  n.cours_id = cours_id;
  n.note = note;
  write(fd, &n, sizeof(struct note));
  close(fd);
}

void print_note(struct etudiant *e, struct note *n) {
  int fd = open("cours.dat", O_RDONLY);
  if(fd < 0) {
    perror("Cannot to open etudiants.dat");
    abort();
  }

  lseek(fd, n->cours_id*sizeof(struct cours), SEEK_SET);
  struct cours c;
  read(fd, &c, sizeof(c));
  assert(c.id == n->cours_id);

  printf("\t%s\t%d\n", c.nom, n->note);  
}

void print_bulletin(struct etudiant *e) {
  int fd = open("notes.dat", O_RDONLY);
  if(fd < 0) {
    perror("Cannot to open etudiants.dat");
    abort();
  }

  struct note n;
  while(read(fd, &n, sizeof(n))>0) {
    if(n.etudiant_id == e->id) {
      print_note(e, &n);
    }
  }
  close(fd);
}

void print_bulletins() {
  int fd = open("etudiants.dat", O_RDONLY);
  if(fd < 0) {
    perror("Cannot to open etudiants.dat");
    abort();
  }
  struct etudiant e;
  while(read(fd, &e, sizeof(e))>0) {
    printf("%d - %s\n", e.id, e.nom);
    print_bulletin(&e);
  }
  close(fd);
}

int main(int argc, char**argv) {
#if 0
  add_etudiant("Hector_le_castor");
  add_etudiant("Augustin_le_lamantin");
  add_etudiant("Annette_la_crevette");
  add_etudiant("Yolande_la_limande");
#endif

#if 0
  add_cours("Système d'exploitation");
  add_cours("Programmation système");
  add_cours("Java");
  add_cours("Anglais");
  add_cours("Traitement du signal");
  add_cours("Allemand");
#endif


#if 0
  add_note(0, 0, 18);
  add_note(0, 1, 16);
  add_note(0, 2, 13);
  add_note(0, 4, 8);

  add_note(1, 0, 11);
  add_note(1, 1, 13);
  add_note(1, 2, 16);
  add_note(1, 3, 15);


  add_note(2, 1, 9);
  add_note(2, 2, 14);
  add_note(2, 3, 11);

  add_note(3, 4, 16);
  add_note(3, 3, 12);

  add_note(4, 0, 14);
  add_note(4, 2, 18);
  add_note(4, 4, 11);
  add_note(4, 3, 16);

  add_note(5, 1, 17);
  add_note(5, 0, 12);
  add_note(5, 2, 8);
  add_note(5, 3, 12);
#endif

  print_bulletins();
  return EXIT_SUCCESS;
}