//----------------------------------------
// Proj3.C
//
//  A first try at a solution to project 3
//
//  Dennis L. Frey  CMSC 202, Fall 2002
//
//  This solution to project 3 does NOT satisfy
//  the requirement for dynamically allocating
//  all local variables. It does satisfy the
//  dynamic array requirement for the book
//  and patron arrays in the Library class 
//
// It's meant to show a reasonable approach 
// to the project if the pointers were not required.
//
//------------------------------------
//
//  This solution is one in which a rather
// large if/else statement is in the middle of
// main() and all the code for each command
// is in-line.  A simple else clause handles
// any invalid commands in the file.
//
// This solution is what we expect
// from you at this point in your programming
// experience.
//-----------------------------------------------
//
// Note that at least the if/else statement is
// arranged with the commands in alphabetical
// order to make it easy to find the code associated
// with each command.  Note the use of whitespace
// and in-line comments to separate the code for
// each command to make it more readable.  Also note
// the use of local variables inside each if/else
// clause.  This makes the code more readable since
// the variables are declared where they are used.
// 
//------------------------------------------------
//  Note the use of a simple function (ReadLine)
// to skip all blank lines in the file without
// needing while loops throughout the code.
// The code for each command relies on the project
// description's guarantee that all necessary data
// for each command will be present.  It's therefore
// only necessary to check the return value from ReadLine()
// when trying to read a new command
//
//-------------------------------------------------------
//  Also note that this code does none of the error
// checking. All error checking and error message generation
// is done in the library class.  This is NOT the best way,
// but error handling is done this way so you'll have something
// to contrast with the correct method of error handling.
// We'll discuss the correct method of error handling soon.
//-----------------------------------------------------
#include <iostream>
#include <fstream>
#include <string>

#include "library.H"

using namespace std;

// function prototypes for functions
// in this file
bool ReadLine (ifstream& in, string& s);

int main (int argc, char *argv[] )
{
   // check for correct number of arguments
   if (argc != 2)
   {
      cerr << "Usage: Proj2 <filename>" << endl;
      exit (-1);
   }
   
   // instantiate and open command file
   ifstream infile (argv[1]);
   if (!infile)
   {
      cerr << "Unable to open file: " << argv[1] << endl;
      exit (-2);
   }


   Library library;
   string command;
      
   // read command from file until eof
   while (ReadLine (infile, command))
   {
      // switch to function for the command

      // add a book to library
      // needs title and author
      if (command == "ADDBOOK")
      {
	 string title, author;
	 ReadLine (infile, title);
	 ReadLine (infile, author);
	 cout << "COMMAND:ADDBOOK," 
	      << title << ", " << author << endl;
	 library.AddBook (title, author);
      }

      // add a patron to the  libary
      // needs patron's name
      else if (command == "ADDPATRON")
      {
	 string name;
	 ReadLine (infile, name);
	 cout << "COMMAND:ADDPATRON, " << name << endl;
	 library.AddPatron (name);
      }

      // list all the books in the library
      // no other data necessary from the file
      else if (command == "BOOKS")
      {
	 cout << "COMMAND:BOOKS" << endl;	 
	 library.ListBooks( );
      }

      // check out a book
      // read book title and patron's name
      else if (command == "CHECKOUT")
      {
	 string title, patron;
	 ReadLine (infile, title);
	 ReadLine (infile, patron);
	 cout << "COMMAND:CHECKOUT, " << title << ", " << patron << endl;
	 library.CheckOut (title, patron);
      }

      // check in a book
      // needs book title from file
      else if (command == "CHECKIN")
      {
	 string title;
	 ReadLine (infile, title);
	 cout << "COMMAND:CHECKIN, " << title << endl;
	 library.CheckIn (title);
      
      }

      // list all patrons in the library
      // nothing else to read from the file
      else if (command == "PATRONS")
      {
	 cout << "COMMAND:PATRONS" << endl;	 
	 library.ListPatrons( );
      }

      // list books checked out by a patron
      // read patron's name from file
      else if (command == "PATRONSBOOKS")
      {
	 string name;
	 ReadLine (infile, name);
	 cout << "COMMAND:PATRONSBOOKS, " << name << endl;
	 library.ListPatronsBooks (name);
      
      }
      else // unkown command; output error
	 cerr << "COMMAND:" << command << " is invalid" << endl;
   }
   return 0;
   
}

//------------------------------------
// ReadLine
// skips blank lines in the file
// returns true if non-blank line read
// returns false on eof
//-----------------------------------
bool ReadLine (ifstream& in, string& s)
{
   s = ""; // empty string with length == 0

   // loop until eof or non-blank string read
   while (!in.eof( ) && s.length() == 0)
   {
      getline (in, s);
      if (s.length() != 0)
	 return true;
   }
   return false;
}