/*
 * ------------------------------------------------------------------------
 * CS2S03/SE2S03, September 2011
 * Assignment 2, Question 2
 * File: PE0214.cpp
 * ------------------------------------------------------------------------
 *
 * This program defines a prototype library database capable of storing
 * information of the card catalog system of a library. It also
 * impletements function SearchBySubject() that takes as parameters the
 * library database and a subject string. For each book in the library that
 * lists the subject string as one of its subject headings, SearchSubject
 * displays the title, the name of the first author, and the Library
 * Congress catalog number of the book.
 * 
 * ------------------------------------------------------------------------
 */

#include "genlib.h"
#include "simpio.h"
#include <iostream>

/* constant definitions */

const int MAX_N_BOOKS = 100;
const int MAX_N_AUTHORS = 5;
const int MAX_N_SUBJECTS = 5;

/* data structures */

struct bookT {
    string title;
    string authors[MAX_N_AUTHORS];
    string catalogNum;
    string subjects[MAX_N_SUBJECTS];
    string publisher;
    int year;
    bool isCirculating;
};

struct LibraryT {
    bookT* books[MAX_N_BOOKS];
    int nBooks;
};

/* Private function prototypes */

void ReadCard(bookT* book);
void SearchBySubject(LibraryT data, string subject);
void Display(bookT book);

/* Main program */

int main() {
    LibraryT libdata;
    bookT* bookptr;
	
    libdata.nBooks = 0;

    /* set up a small library database */
    
    libdata.books[libdata.nBooks] = new bookT;
    if (libdata.books[libdata.nBooks] == NULL) {
        Error("Fail to allocate memory.");
    }
    bookptr = libdata.books[libdata.nBooks];
    bookptr->title = "The C Programming Language";
    bookptr->authors[0] = "Brian W. Kernighan";
    bookptr->authors[1] = "Dennis M. Ritchie";
    bookptr->authors[2] = "";
    bookptr->catalogNum = "Q76.73.C15K47";
    bookptr->subjects[0] = "computer";
    bookptr->subjects[1] = "program language";
    bookptr->subjects[2] = "";
    bookptr->publisher = "Prentice-Hall";
    bookptr->year = 1988;
    bookptr->isCirculating = "y";
    libdata.nBooks++;

    libdata.books[libdata.nBooks] = new bookT;
    if (libdata.books[libdata.nBooks] == NULL) {
        Error("Fail to allocate memory.");
    }
    bookptr = libdata.books[libdata.nBooks];
    bookptr->title = "Relativity";
    bookptr->authors[0] = "Albert Einstein";
    bookptr->authors[1] = "";
    bookptr->catalogNum = "QC6.W48";
    bookptr->subjects[0] = "physics";
    bookptr->subjects[1] = "relativity";
    bookptr->subjects[2] = "";
    bookptr->publisher = "Random House";
    bookptr->year = 1961;
    bookptr->isCirculating = "y";
    libdata.nBooks++;

    libdata.books[libdata.nBooks] = new bookT;
    if (libdata.books[libdata.nBooks] == NULL) {
        Error("Fail to allocate memory.");
    }
    bookptr = libdata.books[libdata.nBooks];
    bookptr->title = "Journey to the Center of the Earth";
    bookptr->authors[0] = "Jules Verne";
    bookptr->authors[1] = "";
    bookptr->catalogNum = "PQ2469.V5E5";
    bookptr->subjects[0] = "fiction";
    bookptr->subjects[1] = "";
    bookptr->publisher = "Dover";
    bookptr->year = 2005;
    bookptr->isCirculating = "y";
    libdata.nBooks++;
	
/* read catalog card information of books and store it in library data base */
    cout << "Number of books you would like to enter, up to ";
    cout << MAX_N_BOOKS - libdata.nBooks << " books: ";
    int n = GetInteger();
    cout << endl;
	
    for (int i = 0; i < n; i++) {
        libdata.books[libdata.nBooks] = new bookT;
        if (libdata.books[libdata.nBooks] == NULL) {
            Error("Fail to allocate memory.");
        }

    ReadCard(libdata.books[libdata.nBooks]);
		
    libdata.nBooks++;
    cout << endl;
    }
	
    cout << endl << "Finished entering books." << endl << endl;
	
    cout << "Search by subject ..." << endl << endl;
	
    cout << "Enter a subject: ";
    string sub = GetLine();
    cout << endl;

    SearchBySubject(&libdata, sub);
	
    return 0;	
}


/* Function: ReadCard()
 * Usage: ReadCard(bookptr)
 * ---------------------------------------------------------------------
 *
 * This function reads catalog card information of a book from the user.
 *
 * ---------------------------------------------------------------------
 */

void ReadCard(bookT* bookptr) {
    string line;

    cout << "Title: ";
    bookptr->title = GetLine();
    cout << "Up to five authors, hit return to end." << endl;
    for (int j = 0; j < MAX_N_AUTHORS; j++) {
        cout << "Author" << j + 1 << " : ";
        line = GetLine();
        (bookptr->authors)[j] = line;
        if (line == "") break;
    }
    cout << "Library of Congress catalog number: ";
    bookptr->catalogNum = GetLine();
    cout << "Up to five subjects, hit return to end." << endl;
    for (int j = 0; j < MAX_N_SUBJECTS; j++) {
        cout << "Subject" << j + 1 << " : ";
        line = GetLine();
        (bookptr->subjects)[j] = line;
        if (line == "") break;
    }
    cout << "Publisher: ";
    bookptr->publisher = GetLine();
    cout << "Year of publication: ";
    bookptr->year = GetInteger();
    cout << "Is circulating? (y or n): ";
    bookptr->isCirculating = (GetLine() == "y");
}

/*
 * Function: SearchBySubject()
 * Usage: SearchSubject(libdata, subject);
 * ------------------------------------------------------------------------
 *
 * This function searches the libdata for books with subject. For each book
 * that lists the subject as one of its subject headings, this function
 * displays its
 * title
 * the first author
 * the Library of Congress catalog number
 *
 * ------------------------------------------------------------------------
 */
 
void SearchBySubject(LibraryT* libdata, string subject) {
    bookT book;
    string sub;
    bool found = false;

    for (int i = 0; i < libdata->nBooks; i++) {
        if (libdata->books[i] == NULL) Error("Library database is corrupted.");
        book = *(libdata->books[i]);
        /* check the subjects */
        for (int j = 0; j < MAX_N_SUBJECTS; j++) {
            sub = book.subjects[j];
            if (sub == "") break;
            if (sub == subject) {
                found = true;
                cout << "Found a book with subject heading " << subject << endl;
                Display(book);
                cout << endl;
            }
        }
    }
    if (!found) {
        cout << "No book found." << endl;
    }
}

/*
 * Function Display()
 * Usage Display(book)
 * -------------------------------------------
 *
 * This function displays the book information
 * title
 * the first author
 * the Library of Congress catalog number
 *
 * -------------------------------------------
 */
 
void Display(bookT book) {
    cout << "title: " << book.title << endl;
    cout << "First author: " << (book.authors)[0] << endl;
    cout << "Library of Congress catalog number: " << book.catalogNum << endl;
}