//------------------------------------------
// Proj3-3.C - second solution to project 3
//
//  Dennis L. Frey  CMSC 202  Fall 2002
//
//  This program improves on the first solution
// by using a switch statement to call a function
// for each command rather than having a very
// large if/else statement with all the code in-line
//  This makes the code much easier to read and maintain
//
//  In order to use the switch statement, this program
// stores the command strings in an array.  The index
// into the array of commands is used for the switch.
// If a new command is added, just add the string to the
// array, add a case to the switch and write the function
//-------------------------------------------------
//
// With this many functions, it's probably a good idea
// to create an auxiliary .C and .H file.

//-----------------------------------------------
#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);
void AddBook   (ifstream& in, Library& library);
void AddPatron (ifstream& in, Library& library);
void Books     (const Library& lib);
void CheckIn   (ifstream& in, Library& lib);
void CheckOut  (ifstream& in, Library& lib);
void Patrons   (const Library& lib);
void PatronsBooks (ifstream& in, const Library& lib);

// const ints for each command
const int ADDBOOK      = 0;
const int ADDPATRON    = 1;
const int BOOKS        = 2;
const int PATRONS      = 3;
const int CHECKIN      = 4;
const int CHECKOUT     = 5;
const int PATRONSBOOKS = 6;

// array of command strings
// same order as const ints above
const int NRCOMMANDS   = 7;
const string commands[NRCOMMANDS] =
{"ADDBOOK", "ADDPATRON", "BOOKS", "PATRONS",
 "CHECKIN", "CHECKOUT",  "PATRONSBOOKS"
};

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

   // all ok - instantiate the library
   Library library;
   string command;

   // Loop until no more commands in the file
   while (ReadLine (infile, command))
   {
      // switch to function for the command
      // 'while' uses short-circuit evaluation
      int i = 0;
      while ((i < NRCOMMANDS) && (commands[i] != command))
	 i++;

      switch (i)            // one case for each command
      {
	 case ADDBOOK:      AddBook (infile, library);      break;
	 case ADDPATRON:    AddPatron (infile, library);    break;
	 case BOOKS:        Books (library);                break;
	 case CHECKIN:      CheckIn (infile, library);      break;
	 case CHECKOUT:     CheckOut (infile, library);     break;
	 case PATRONS:      Patrons (library);              break;
	 case PATRONSBOOKS: PatronsBooks (infile, library); break;
	 default:           // else bad command
	    cerr << "Invalid command: " << command << endl;
	    break;
      }
   }
   return 0;
}

//-----------------------------------------------
// AddBook
//  Reads title and author from file, echos command
// and adds the book to the library
//-----------------------------------------------
void AddBook (ifstream& infile, Library& library)
{
   string title, author;

   ReadLine (infile, title);
   ReadLine (infile, author);
   cout << "ADDBOOK: " << title << ", " << author << endl;
   library.AddBook (title, author);
}

//--------------------------------------------
// AddPatron
//   reads patron info from the file
//   echos command and adds patron to library
//--------------------------------------------
void AddPatron (ifstream& infile, Library& library)
{
    string name;
    ReadLine (infile, name);
    cout << "COMMAND:ADDPATRON, "<< name << endl;
    library.AddPatron (name);
}

//--------------------------------------------
// Books
//   Prints all books in the library 
//-------------------------------------------
void Books (const Library& library)
{
   cout << "COMMAND:BOOKS" << endl;	 
   library.ListBooks( );

}

//----------------------------------------------
// CheckIn
//  reads title from input file, echos
// command and checks in book 
//----------------------------------------------
void CheckIn (ifstream &infile, Library& library)
{
    string title;
    ReadLine (infile, title);
    cout << "COMMAND:CHECKIN, " << title << endl;
    library.CheckIn (title);
}


//-------------------------------------------------
// CheckOut
//  Reads title and patron from file, echos command
// checks out book if no errors detected
//-------------------------------------------------
void CheckOut (ifstream& infile, Library& library)
{
   string title, patron;

   ReadLine (infile, title);
   ReadLine (infile, patron);
   cout << "CHECKOUT: " << title << ", " << patron << endl;
   library.CheckOut (title, patron);
}


//---------------------------------------
// Patrons
//   Lists all patrons in the library
//-----------------------------------------
void Patrons (const Library& library)
{
    cout << "COMMAND:PATRONS" << endl;	 
    library.ListPatrons( );
}

//------------------------------------------------
// PatronsBooks
//    Reads patron's name from file and lists
// books he has checkedout of library
//------------------------------------------------
void PatronsBooks (ifstream& infile, const Library& library)
{
    string name;
    ReadLine (infile, name);
    cout << "COMMAND:PATRONSBOOKS, " << name << endl;
    library.ListPatronsBooks (name);
}

//------------------------------------------------
// 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;
   }

   // eof
   return false;
}