a2_functions.c

/*****************
    Student Name 	= Marwan Alakhras
    Student Number	= 101296201
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#include <time.h>
#include "a2_nodes.h"
#include "a2_functions.h"
#include <assert.h>
#include <ctype.h>

// Your solution goes here



/*
   ******** DONT MODIFY THIS FUNCTION ********
   Function that reads users from the text file.
   IMPORTANT: This function shouldn't be modified and used as is
   ******** DONT MODIFY THIS FUNCTION ********
*/
user_t *read_CSV_and_create_users(FILE *file, int num_users)
{
    srand(time(NULL));
    user_t *users = NULL;
    char buffer[500];
    fgets(buffer, sizeof(buffer), file); // Read and discard the header line
    int count = 0;
    for (int i = 0; i < num_users; i++)
    {
        fgets(buffer, sizeof(buffer), file);
        buffer[strcspn(buffer, "\r\n")] = 0; // Remove newline characters

        char *token = strtok(buffer, ",");
        char *token2 = strtok(NULL, ",");
        users = add_user(users, token, token2);
        char *username = token;

        token = strtok(NULL, ",");

        user_t *current_user = users;
        for (; current_user != NULL && strcmp(current_user->username, username) != 0; current_user = current_user->next)
            ;

        while (token != NULL && strcmp(token, ",") != 0 && count < 3)
        {
            if (strcmp(token, " ") != 0)
            {
                add_friend(current_user, token);
            }
            token = strtok(NULL, ",");
            count++;
        }
        count = 0;

        // token = strtok(NULL, ",");
        while (token != NULL && strcmp(token, ",") != 0)
        {
            add_post(current_user, token);
            token = strtok(NULL, ",");
        }
    }
    return users;
}




void print_menu(){

    printf("***********************************\n");
    printf("\t    MAIN MENU\n");
    printf("***********************************\n");

    printf("1. Register a new user\n");
    printf("2. Login with an existing user's information\n");
    printf("3. Exit\n");
}


user_t *add_user(user_t *users, const char *username, const char *password){

    user_t *newuser = malloc(sizeof(user_t));
    assert(newuser != NULL);

    strcpy(newuser->username, username);
    strcpy(newuser->password, password);
    newuser->friends = NULL;
    newuser->posts = NULL; 
    newuser->next = NULL;
    
    if (users == NULL || strcmp(username, users->username) < 0){//Inserts at head of list
        newuser->next = users;
        return newuser;
    }

    user_t *current_user = users;
    while (current_user->next != NULL && strcmp(current_user->next->username, username) < 0){
        current_user = current_user->next; //Traverses the list up to the point the newuser must be inserted 
    }

    newuser->next = current_user->next;
    current_user->next = newuser;
    return users;

}


user_t *find_user(user_t *users, const char *username){
    for(user_t *current_user = users ;current_user!=NULL; current_user=current_user->next){
        if (strcmp(current_user->username , username) == 0){ //User was found
            return current_user;
        }
    }   

    return NULL; //User was not found
}


void add_post(user_t *user, const char *text){
    
    assert(user !=NULL);
    post_t *newpost = create_post(text);
    assert(newpost !=NULL);
    
    newpost->next = user->posts;
    user->posts = newpost;

}


post_t *create_post(const char *text){
    post_t *newpost = malloc(sizeof(post_t));
    assert(newpost!=NULL);
    strcpy(newpost->content, text);
    newpost->next = NULL;
    return newpost;
}

void display_all_user_posts(user_t *user){
    
    post_t *current_user = user->posts;
    for(int i = 1 ; current_user != NULL; current_user = current_user->next, i++){
        printf("%i - %s\n", i , current_user->content);
    }
}

_Bool delete_post(user_t *user){
    
    post_t *to_delete = user->posts;
    if(to_delete == NULL){//No posts to delete
        return false;
    }
    user->posts = to_delete->next;
    free(to_delete);
    to_delete = NULL;
    return true;

}



void add_friend(user_t *user, const char *friend){
    
    assert(user != NULL);

    friend_t *newfriend = create_friend(friend);
    assert(newfriend !=NULL);
    
    newfriend->posts = &(find_user(user, friend)->posts);
    
    if (user->friends == NULL || strcmp(friend, user->friends->username) < 0 ){
        newfriend->next = user->friends;
        user->friends = newfriend;
        return;
    }
    friend_t *current_user = user->friends;
    while(current_user->next != NULL && strcmp(current_user->next->username, friend ) < 0){
        current_user = current_user->next; //Traverses the linked list up to the point the newfriend must be inserted.
    }
    newfriend->next = current_user->next;
    current_user->next = newfriend;

}

friend_t *create_friend(const char *username){
    
    friend_t *newfriend = malloc(sizeof(friend_t));
    assert(newfriend != NULL);
    strcpy(newfriend->username, username);
    newfriend->next = NULL;
    newfriend->posts = NULL;
    
    return newfriend;
}


_Bool delete_friend(user_t *user, char *friend_name){
    friend_t *to_delete = user->friends;
    if(to_delete == NULL){//No friend to delete because user has no friends
        return false;
    }
    
    if (strcmp(to_delete->username , friend_name) == 0){ //If the friend is at the head of the linked list
        user->friends = to_delete->next;
        free(to_delete); 
        to_delete = NULL;
        return true;

    }
    
    for(friend_t *previous = NULL ,*current_user = user->friends ; current_user != NULL ; previous = current_user, current_user= current_user->next){
        if (strcmp(current_user->username , friend_name) == 0){
            to_delete = current_user;
            previous->next = current_user->next;
            free(to_delete); 
            to_delete = NULL;
            return true;
        }
    }
    return false;
    
}


void display_user_friends(user_t *user){
    
    friend_t *current_user = user->friends;
    for(int i = 1 ; current_user != NULL; current_user = current_user->next, i++){
        printf("%i - %s\n", i , current_user->username);
    }
}

_Bool is_friend(user_t *user, char *friend_name){
    
    for (friend_t *current_user = user->friends; current_user != NULL; current_user = current_user->next){
        if(strcmp(current_user->username, friend_name) == 0){
            return true; //friend found
        }
    }
    return false;   //friend not found
}


void display_posts_by_n(user_t *users, int number){

    if(users == NULL){ //User not found
        printf("User not found.\n");
        return;
    }
    else{ //User found
        post_t *current_user = users->posts;
        int counter = 1;
        char choice;
        
        if(current_user == NULL){
            printf("User has no posts.\n");
        }

        while(current_user!= NULL){
            printf("%s's posts:\n", users->username);
            for (int i = 1; i<=number && current_user != NULL; i++, current_user= current_user->next){
                printf("%i - %s\n", counter++, current_user->content);
            }
            if(current_user == NULL){
                printf("All posts have been displayed.\n");
                break;
            }
            
            
            while(true){
                printf("Do you want to display more posts? (Y/N/y/n): ");
                scanf(" %c", &choice);

                if(toupper(choice) == 'Y'){
                    break; //Continue displaying posts
                }
                else if (toupper(choice) == 'N'){
                    return; //Return to main menu
                }
                else{
                    printf("Invalid input. ");
                }
            }


        }

    }

}


void teardown(user_t *users){
    user_t *current_user = users;
    
    while(users!=NULL){ //Freeing each user

        friend_t *current_friend; //Freeing the user's friends
        while(current_user->friends != NULL){
            current_friend = current_user->friends->next;
            free(current_user->friends);
            current_user->friends = current_friend;

        }
        current_user->friends = NULL;



        post_t *current_post; //Freeing the user's posts
        while(current_user->posts != NULL){
            current_post = current_user->posts->next;
            free(current_user->posts);
            current_user->posts = current_post;

        }
        current_user->posts = NULL;

        current_user = users->next;
        free(users);
        users = current_user;

    }
    
}

char * make_lowercase(char * username){
    for (int i = 0; i < strlen(username); i++){
        username[i] = tolower(username[i]);
        return username;
    }
}