// Oldham, Jeffrey D.
// 2000Mar25
// CS1321
//
// Modified by:
// Massingill, Berna L.
// 2001Apr

// Test the Deque Implementation

#include <iostream>
#include <cstdlib>		// has EXIT_SUCCESS
#include <cassert>
#include <string>
#include "deque.h"
using namespace std;

int main(void)
{
  deque dq;
  string prompt =
    "Please enter an operation to perform:\n"
    "    ?: this prompt again\n"
    "    q: quit\n"
    "    f: return front char\n"
    "    F<char>: replace front char\n"
    "    Pf<char>: push_front\n"
    "    pf: pop_front\n"
    "    b: return back char\n"
    "    B: replace back char\n"
    "    Pb<char>: push_back\n"
    "    pb: pop_back\n"
    "    r<number>: read <number>-th element\n"
    "    R<char><number>: replace <number>-th element\n";
  string reply;
  cout << prompt;
  while (getline(cin, reply)) {
    if (reply.size() > 0) {
      char c = reply[0];
      if (c == '?')
	cout << prompt;
      else if (c == 'q' || c == 'Q')
	return EXIT_SUCCESS;
      else if (c == 'P' && reply.size() >= 3) {	// push
	if (reply[1] == 'f')
	  dq.push_front(reply[2]);
	else if (reply[1] == 'b')
	  dq.push_back(reply[2]);
	else
	  cerr << "Invalid command\n";
      }
      else if (c == 'p' && reply.size() >= 2) {	// pop
	if (dq.empty())
	  cerr << "Error:  empty deque\n";
	else if (reply[1] == 'f')
	  dq.pop_front();
	else if (reply[1] == 'b')
	  dq.pop_back();
	else
	  cerr << "Invalid command\n";
      }
      else if (c == 'f') {	// front (read)
	if (dq.empty())
	  cerr << "Error:  empty deque\n";
	else
	  cout << "The front is " << dq.front() << endl;
      }
      else if (c == 'b') {	// back (read)
	if (dq.empty())
	  cerr << "Error:  empty deque\n";
	else
	  cout << "The back is " << dq.back() << endl;
      }
      else if (c == 'F' && reply.size() >= 2) {	// front (change)
	if (dq.empty())
	  cerr << "Error:  empty deque\n";
	else
	  dq.front() = reply[1];
      }
      else if (c == 'B' && reply.size() >= 2) {	// back (change)
	if (dq.empty())
	  cerr << "Error:  empty deque\n";
	else
	  dq.back() = reply[1];
      }
      else if (c == 'r' && reply.size() >= 2) { // i-th elem. (read)
	deque::size_type i = atoi(reply.substr(1).c_str());
	if (i >= dq.size())
	  cerr << "Error:  index out of bounds\n";
	else
	  cout << "The " << i << "-th element = " << dq[i] << endl;
      }
      else if (c == 'R' && reply.size() >= 3) { // i-th elem. (change)
	deque::size_type i = atoi(reply.substr(2).c_str());
	if (i >= dq.size())
	  cerr << "Error:  index out of bounds\n";
	else
	  dq[i] = reply[1];
      }
      else
	cerr << "Invalid command\n";
    }
    if (dq.empty())
      cout << "Empty deque (" << dq.size() << ") elements:  " 
	   << dq << endl;
    else
      cout << "Deque (" << dq.size() << ") elements:  " 
	   << dq << endl;
  }
  return EXIT_SUCCESS;
}