(function($) {
    var pasteEventName = ($.browser.msie ? 'paste' : 'input') + ".mask";
    var iPhone = (window.orientation != undefined);

    $.mask = {
        definitions: {
            '9': "[0-9]",
            'a': "[A-Za-z]",
            '*': "[A-Za-z0-9]"
        }
    };

    $.fn.extend({
        caret: function(begin, end) {
            if (this.length == 0) return;
            if (typeof begin == 'number') {
                end = (typeof end == 'number') ? end : begin;
                return this.each(function() {
                    if (this.setSelectionRange) {
                        this.focus();
                        this.setSelectionRange(begin, end);
                    } else if (this.createTextRange) {
                        var range = this.createTextRange();
                        range.collapse(true);
                        range.moveEnd('character', end);
                        range.moveStart('character', begin);
                        range.select();
                    }
                });
            } else {
                if (this[0].setSelectionRange) {
                    begin = this[0].selectionStart;
                    end = this[0].selectionEnd;
                } else if (document.selection && document.selection.createRange) {
                    var range = document.selection.createRange();
                    begin = 0 - range.duplicate().moveStart('character', -100000);
                    end = begin + range.text.length;
                }
                return { begin: begin, end: end };
            }
        },
        unmask: function() { return this.trigger("unmask"); },
        mask: function(mask, settings) {
            if (!mask && this.length > 0) {
                var input = $(this[0]);
                var tests = input.data("tests");
                return $.map(input.data("buffer"), function(c, i) {
                    return tests[i] ? c : null;
                }).join('');
            }
            settings = $.extend({
                placeholder: "_",
                completed: null
            }, settings);

            var defs = $.mask.definitions;
            var tests = [];
            var partialPosition = mask.length;
            var firstNonMaskPos = null;
            var len = mask.length;

            $.each(mask.split(""), function(i, c) {
                if (c == '?') {
                    len--;
                    partialPosition = i;
                } else {
                    tests.push(defs[c] ? new RegExp(defs[c]) : null);
                    if (tests[tests.length - 1] && firstNonMaskPos == null)
                        firstNonMaskPos = tests.length - 1;
                }
            });

            return this.each(function() {
                var input = $(this);
                var buffer = $.map(mask.split(""), function(c, i) { if (c != '?') return defs[c] ? settings.placeholder : c });
                var ignore = false;
                var focusText = input.val();

                input.data("buffer", buffer).data("tests", tests);

                function seekNext(pos) {
                    while (++pos < len) {
                        if (tests[pos])
                            return pos;
                    }
                    return len;
                };

                function shiftL(pos) {
                    while (!tests[pos] && pos >= 0) pos--;
                    for (var i = pos; i < len; i++) {
                        if (tests[i]) {
                            buffer[i] = settings.placeholder;
                            var j = seekNext(i);
                            if (j < len && tests[i].test(buffer[j])) {
                                buffer[i] = buffer[j];
                            } else
                                break;
                        }
                    }
                    writeBuffer();
                    input.caret(Math.max(firstNonMaskPos, pos));
                };

                function shiftR(pos) {
                    for (var i = pos, c = settings.placeholder; i < len; i++) {
                        if (tests[i]) {
                            var j = seekNext(i);
                            var t = buffer[i];
                            buffer[i] = c;
                            if (j < len && tests[j].test(t))
                                c = t;
                            else
                                break;
                        }
                    }
                };

                function keydownEvent(e) {
                    var pos = $(this).caret();
                    var k = e.keyCode;
                    ignore = (k < 16 || (k > 16 && k < 32) || (k > 32 && k < 41));

                    if ((pos.begin - pos.end) != 0 && (!ignore || k == 8 || k == 46))
                        clearBuffer(pos.begin, pos.end);

                    if (k == 8 || k == 46 || (iPhone && k == 127)) {
                        shiftL(pos.begin + (k == 46 ? 0 : -1));
                        return false;
                    } else if (k == 27) {
                        clearBuffer(0, len);
                        writeBuffer();
                        $(this).caret(firstNonMaskPos);
                        return false;
                    }
                };

                function keypressEvent(e) {
                    if (ignore) {
                        ignore = false;
                        return (e.keyCode == 8) ? false : null;
                    }
                    e = e || window.event;
                    var k = e.charCode || e.keyCode || e.which;
                    var pos = $(this).caret();

                    if (e.ctrlKey || e.altKey) {
                        return true;
                    } else if ((k >= 41 && k <= 122) || k == 32 || k > 186) {
                        var p = seekNext(pos.begin - 1);
                        if (p < len) {
                            var c = String.fromCharCode(k);
                            if (tests[p].test(c)) {
                                shiftR(p);
                                buffer[p] = c;
                                writeBuffer();
                                var next = seekNext(p);
                                $(this).caret(next);
                                if (settings.completed && next == len)
                                    settings.completed.call(input);
                            }
                        }
                    }
                    return false;
                };

                function clearBuffer(start, end) {
                    for (var i = start; i < end && i < len; i++) {
                        if (tests[i])
                            buffer[i] = settings.placeholder;
                    }
                };

                function writeBuffer() { return input.val(buffer.join('')).val(); };

                function checkVal(allow) {
                    var test = input.val();
                    var lastMatch = -1;
                    for (var i = 0, pos = 0; i < len; i++) {
                        if (tests[i]) {
                            buffer[i] = settings.placeholder;
                            while (pos++ < test.length) {
                                var c = test.charAt(pos - 1);
                                if (tests[i].test(c)) {
                                    buffer[i] = c;
                                    lastMatch = i;
                                    break;
                                }
                            }
                            if (pos > test.length)
                                break;
                        }
                    }
                    if (!allow && lastMatch + 1 < partialPosition) {
                        input.val("");
                        clearBuffer(0, len);
                    } else if (allow || lastMatch + 1 >= partialPosition) {
                        writeBuffer();
                        if (!allow) input.val(input.val().substring(0, lastMatch + 1));
                    }
                    return (partialPosition ? i : firstNonMaskPos);
                };

                input
					.one("unmask", function() {
					    input
							.unbind(".mask")
							.removeData("buffer")
							.removeData("tests");
					})
					.bind("focus.mask", function() {
					})
					.bind("blur.mask", function() {
					    if (input.val() != focusText)
					        input.change();
					})
					.bind("keydown.mask", keydownEvent)
					.bind("keypress.mask", keypressEvent)
					.bind(pasteEventName, function() {
					    setTimeout(function() { input.caret(checkVal(true)); }, 0);
					});
            });
        }
    });
})(jQuery);