/*
 * 6502 Based Virtual Computer
 *	Copyright (C) 2011  Scott C. Duensing <scott@jaegertech.com>
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License along
 *	with this program; if not, write to the Free Software Foundation, Inc.,
 *	51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

// Our keyboard object.
function keyboard() {

	// OMFGWTFBBQ - http://unixpapa.com/js/key.html

	// --- Private variables.

	// Memory location for keyboard status.
	var MEMORY            = null;
	var MEMORY_START      = 0;
	var CHARACTER_ADDRESS = 0;
	var META_ADDRESS      = 0;
	var RUNNING           = false;


	// --- Public methods.

	// Attach keyboard to DOM.
	this.attach = function(newMemory, newStartPosition) {
		MEMORY       = newMemory;
		MEMORY_START = newStartPosition;
		CHARACTER_ADDRESS = MEMORY_START;
		META_ADDRESS      = MEMORY_START + 1;
	};

	// Keyboard handler for use with Meteor.
	this.handleEvent = function(event) {
		// Process the key press.
		var code = event.which || window.event.keyCode;
		var k = {
			code:  code,
			shift: event.shiftKey,
			alt:   event.altKey,
			ctrl:  event.ctrlKey
		};
		var processIt = false;
		if (event.type == "keydown") {
			if ((code == 8) ||
				(code ==  9) ||
				(code == 27))
					processIt = true;
		}
		if (event.type == "keypress") {
			processIt = true;
		}
		//console.log(code + " " + event.type + " " + processIt);
		if (processIt) {
			// Write meta first.  Then we can process on the character being written.
			MEMORY.writeByte(META_ADDRESS, (k.alt * 4) + (k.ctrl * 2) + k.shift);
			// Ignore "naked" meta keys in the character address.
			if ((k.code != 16) && (k.code != 17) && (k.code != 18) && (k.code != 145) && (k.code != 146)) {
				MEMORY.writeByte(CHARACTER_ADDRESS, k.code);
			}
		}
		return !processIt;
	};

	// Deserialize keyboard state.
	this.deserialize = function(state) {
		RUNNING = state.R;
	};

	// Fetch how much RAM the current settings will require.
	this.getMemoryNeeded = function() {
		return 2; // Complicated, huh?
	};

	// Pause the keyboard.
	this.pause = function() {
		console.log("Pausing Keyboard.");
		RUNNING = false;
	};

	// Start the keyboard.
	this.run = function() {
		console.log("Starting Keyboard.");
		RUNNING = true;
	};

	// Serialize keyboard state.
	this.serialize = function() {
		var state = {
			R: RUNNING
		};
		return state;
	};
}