#include "functions.h"

void storeBooks(Book *books_list,char path[100])
	{
	FILE *f;
	Book *cur, *temp;
		f = fopen(path,"w");
	for (cur=books_list;cur!=NULL;temp = cur,cur=cur->next,free(temp))
	{
		fprintf(f,"%s $$$ %d\n",cur->name,cur->copies);
	}
	fclose(f);
	}

	void borrowBook(Book *books_list, char book_name[NAME_LENGTH], int copies)
	{
		Book *cur, *prev=NULL;
		for (cur = books_list;cur!=NULL;prev = cur,cur=cur->next)
		{
			if (strcmp(book_name,cur->name) == 0)
			{
				cur->copies -=copies;
				if (cur->copies <1)
				{
					if (prev !=NULL)
					{
						prev = remove_from(cur,prev);
					}
					else
					{
						books_list = remove_from(cur,prev);
					}
				}
			}
		}
	}

Book* initBooksList(Book *p)
	{

	FILE *fp = fopen("books.txt","r"); /* fp!=NULL checked at main */
	if (fp == NULL){
		exit(0);
	}
    char str[MAX_ROW];
    int actual_len = 0, cpy = 0,i;
	Book* init = p;
    Book* buffer = NULL;
    while (EOF != fgets(str, MAX_ROW, fp)){
		if (p == NULL)
		{
			char book_name_buffer[NAME_LENGTH];
			cpy = 0;
			p = (Book *)malloc(sizeof(Book));
			if (p == NULL) exit(1);
            for (int i = 0; str[i+1] != '$'; i++)
			{
                book_name_buffer[i] = str[i];
                actual_len += 1;
			}
            for (int i = actual_len+5; str[i] != '\n'; i++)
			{
                cpy = cpy * 10 + (int) (str[i]-'0');
            }
			strcpy(p->name, book_name_buffer);
			p->copies = cpy;
			p->next = NULL;
			actual_len = 0;
			init = p;
		}
        else{
			char book_name_buffer[NAME_LENGTH];
			actual_len = 0;
			cpy = 0;
			for (int i = 0; i < NAME_LENGTH; i++){
				book_name_buffer[i] = "";
			}
            for (int i = 0; str[i + 1] != '$'; i++)
			{
                book_name_buffer[i] = str[i];
                actual_len += 1;
			}

            for (int i = actual_len+5; str[i] != '\n'; i++)
			{

					cpy = cpy * 10 + (int)(str[i] - '0');

            }
			Book* new_book = (Book *)malloc(sizeof(Book));
			if (new_book == NULL)
				exit(1);
			strcpy(new_book->name, book_name_buffer);
			new_book->copies = cpy;
			new_book->next = NULL;
			buffer = p;
            while (p != NULL && strcmp(new_book->name, p->name) > 0){
                buffer = p;
                p = p->next;
            }
			if (p == NULL){
				buffer->next = new_book;
			}
			else{
				buffer->next = new_book;
				new_book->next = p;
			}
			new_book = NULL;
        }
		p = init;
		buffer = NULL;
    }
    fclose(fp);
    return p;
}
Book* returnBook(char book_name[MAX_ROW],int cpy,Book *p){
    Book *init = p;
    Book *buffer = p;
    while (p->name != book_name && p != NULL){
        p = p->next;
    }
    if (p == NULL){
        Book* new_book = (Book*)malloc(sizeof(Book*));
		if (new_book == NULL)
			exit(1);
        strcpy(new_book->name, book_name);
        new_book->copies = cpy;
        while (p != NULL && strcmp(new_book->name, p->name) > 0){
            buffer = p;
            p = p->next;
        }
        if (p == NULL){
            buffer->next = new_book;
            new_book->next = NULL;
        }
        else{
            buffer->next = new_book;
            new_book->next = p;
        }
    }
    else{
        p->copies += cpy;
    }
    p = init;
    return p;
}