/*
 * jwerty - Awesome handling of keyboard events
 *
 * jwerty is a JS lib which allows you to bind, fire and assert key combination
 * strings against elements and events. It normalises the poor std api into
 * something easy to use and clear.
 *
 * This code is licensed under the MIT
 * For the full license see: http://keithamus.mit-license.org/
 * For more information see: http://keithamus.github.com/jwerty
 *
 * @author Keith Cirkel ('keithamus') <jwerty@keithcirkel.co.uk>
 * @license http://keithamus.mit-license.org/
 * @copyright Copyright © 2011, Keith Cirkel
 *
 */
(function (global, exports) {

    // Try require external librairies in Node.js context
    function tryRequire(mod) {
        if (typeof require == 'function' && typeof module !== 'undefined' && module.exports) {
            try {
                return require(mod.toLowerCase());
            } catch (err) {}
        } else {
            return global[mod];
        }
    }

    // Helper methods & vars:
    var $d = global.document,
        $ = (tryRequire('jQuery') || tryRequire('Zepto') || tryRequire('ender') || $d),
        $$, // Element selector function
        $b, // Event binding function
        $u, // Event unbinding function
        $f, // Event firing function
        ke = 'keydown';

    function realTypeOf(v, s) {
        return (v === null) ? s === 'null'
        : (v === undefined) ? s === 'undefined'
        : (v.is && v instanceof $) ? s === 'element'
        : Object.prototype.toString.call(v).toLowerCase().indexOf(s) > 7;
    }

    if ($ === $d) {
        $$ = function (selector, context) {
            return selector ? $.querySelector(selector, context || $) : $;
        };
        $b = function (e, fn) { e.addEventListener(ke, fn, false); };
        $u = function (e, fn) { e.removeEventListener(ke, fn, false); };
        $f = function (e, jwertyEv) {
            var ret = $d.createEvent('Event'),
            i;

            ret.initEvent(ke, true, true);

            for (i in jwertyEv) ret[i] = jwertyEv[i];

            return (e || $).dispatchEvent(ret);
        };
    } else {
        $$ = function (selector, context) { return $(selector || $d, context); };
        $b = function (e, fn) { $(e).bind(ke + '.jwerty', fn); };
        $u = function (e, fn) { $(e).unbind(ke + '.jwerty', fn) };
        $f = function (e, ob) { $(e || $d).trigger($.Event(ke, ob)); };
    }

    // Private
    var _modProps = { 16: 'shiftKey', 17: 'ctrlKey', 18: 'altKey', 91: 'metaKey' };

    // Generate key mappings for common keys that are not printable.
    var _keys = {

        // MOD aka toggleable keys
        mods: {
            // Shift key, ?
            '?': 16,
            shift: 16,
            // CTRL key, on Mac: ^
            '^': 17,
            ctrl: 17,
            // ALT key, on Mac: ? (Alt)
            '?': 18,
            alt: 18,
            option: 18,
            // META, on Mac: ? (CMD), on Windows (Win), on Linux (Super)
            '?': 91,
            meta: 91,
            cmd: 91,
            'super': 91,
            win: 91
        },

        // Normal keys
        keys: {
            // Backspace key, on Mac: ? (Backspace)
            '?': 8,
            backspace: 8,
            // Tab Key, on Mac: ? (Tab), on Windows ??
            '?': 9,
            '?': 9,
            tab: 9,
            // Return key, ?
            '?': 13,
            'return': 13,
            enter: 13,
            '?': 13,
            // Pause/Break key
            'pause': 19,
            'pause-break': 19,
            // Caps Lock key, ?
            '?': 20,
            caps: 20,
            'caps-lock': 20,
            // Escape key, on Mac: ?, on Windows: Esc
            '?': 27,
            escape: 27,
            esc: 27,
            // Space key
            space: 32,
            // Page-Up key, or pgup, on Mac: ?
            '?': 33,
            pgup: 33,
            'page-up': 33,
            // Page-Down key, or pgdown, on Mac: ?
            '?': 34,
            pgdown: 34,
            'page-down': 34,
            // END key, on Mac: ?
            '?': 35,
            end: 35,
            // HOME key, on Mac: ?
            '?': 36,
            home: 36,
            // Insert key, or ins
            ins: 45,
            insert: 45,
            // Delete key, on Mac: ? (Delete)
            del: 46,
            'delete': 46,

            // Left Arrow Key, or ?
            '?': 37,
            left: 37,
            'arrow-left': 37,
            // Up Arrow Key, or ?
            '?': 38,
            up: 38,
            'arrow-up': 38,
            // Right Arrow Key, or ?
            '?': 39,
            right: 39,
            'arrow-right': 39,
            // Up Arrow Key, or ?
            '?': 40,
            down: 40,
            'arrow-down': 40,

            // odities, printing characters that come out wrong:
            // Num-Multiply, or *
            '*': 106,
            star: 106,
            asterisk: 106,
            multiply: 106,
            // Num-Plus or +
            '+': 107,
            'plus': 107,
            // Num-Subtract, or -
            '-': 109,
            subtract: 109,
            'num-.': 110,
            'num-period': 110,
            'num-dot': 110,
            'num-full-stop': 110,
            'num-delete': 110,
            // Semicolon
            ';': 186,
            semicolon: 186,
            // = or equals
            '=': 187,
            'equals': 187,
            // Comma, or ,
            ',': 188,
            comma: 188,
            //'-': 189, //???
            // Period, or ., or full-stop
            '.': 190,
            period: 190,
            'full-stop': 190,
            // Slash, or /, or forward-slash
            '/': 191,
            slash: 191,
            'forward-slash': 191,
            // Tick, or `, or back-quote
            '`': 192,
            tick: 192,
            'back-quote': 192,
            // Open bracket, or [
            '[': 219,
            'open-bracket': 219,
            // Back slash, or \
            '\\': 220,
            'back-slash': 220,
            // Close backet, or ]
            ']': 221,
            'close-bracket': 221,
            // Apostraphe, or Quote, or '
            '\'': 222,
            quote: 222,
            apostraphe: 222
        }

    };

    // To minimise code bloat, add all of the 0-9 and NUMPAD 0-9 keys in a loop
    var i = 47,
        n = 0;
    while (++i < 106) {
        _keys.keys[n] = i;
        _keys.keys['num-' + n] = i + 48;
        ++n;
    }

    // To minimise code bloat, add all of the F1-F25 keys in a loop
    i = 111,
    n = 1;
    while (++i < 136) {
        _keys.keys['f' + n] = i;
        ++n;
    }

    // To minimise code bloat, add all of the letters of the alphabet in a loop
    i = 64;
    while (++i < 91) {
        _keys.keys[String.fromCharCode(i).toLowerCase()] = i;
    }

    function JwertyCode(jwertyCode) {
        var i,
            c,
            n,
            z,
            keyCombo,
            optionals,
            jwertyCodeFragment,
            rangeMatches,
            rangeI;

        // In-case we get called with an instance of ourselves, just return that.
        if (jwertyCode instanceof JwertyCode) return jwertyCode;

        // If jwertyCode isn't an array, cast it as a string and split into array.
        if (!realTypeOf(jwertyCode, 'array')) {
            jwertyCode = (String(jwertyCode)).replace(/\s/g, '').toLowerCase()
                .match(/(?:\+,|[^,])+/g);
        }

        // Loop through each key sequence in jwertyCode
        for (i = 0, c = jwertyCode.length; i < c; ++i) {

            // If the key combo at this part of the sequence isn't an array,
            // cast as a string and split into an array.
            if (!realTypeOf(jwertyCode[i], 'array')) {
                jwertyCode[i] = String(jwertyCode[i])
                    .match(/(?:\+\/|[^\/])+/g);
            }

            // Parse the key optionals in this sequence
            optionals = [],
            n = jwertyCode[i].length;
            while (n--) {

                // Begin creating the object for this key combo
                jwertyCodeFragment = jwertyCode[i][n];

                keyCombo = {
                    jwertyCombo: String(jwertyCodeFragment),
                    shiftKey: false,
                    ctrlKey: false,
                    altKey: false,
                    metaKey: false
                };

                // If jwertyCodeFragment isn't an array then cast as a string
                // and split it into one.
                if (!realTypeOf(jwertyCodeFragment, 'array')) {
                    jwertyCodeFragment = String(jwertyCodeFragment).toLowerCase()
                        .match(/(?:(?:[^\+])+|\+\+|^\+$)/g);
                }

                z = jwertyCodeFragment.length;
                while (z--) {

                    // Normalise matching errors
                    if (jwertyCodeFragment[z] === '++') jwertyCodeFragment[z] = '+';

                    // Inject either keyCode or ctrl/meta/shift/altKey into keyCombo
                    if (jwertyCodeFragment[z] in _keys.mods) {
                        keyCombo[_modProps[_keys.mods[jwertyCodeFragment[z]]]] = true;
                    } else if (jwertyCodeFragment[z] in _keys.keys) {
                        keyCombo.keyCode = _keys.keys[jwertyCodeFragment[z]];
                    } else {
                        rangeMatches = jwertyCodeFragment[z].match(/^\[([^-]+\-?[^-]*)-([^-]+\-?[^-]*)\]$/);
                    }
                }
                if (realTypeOf(keyCombo.keyCode, 'undefined')) {
                    // If we picked up a range match earlier...
                    if (rangeMatches && (rangeMatches[1] in _keys.keys) && (rangeMatches[2] in _keys.keys)) {
                        rangeMatches[2] = _keys.keys[rangeMatches[2]];
                        rangeMatches[1] = _keys.keys[rangeMatches[1]];

                        // Go from match 1 and capture all key-comobs up to match 2
                        for (rangeI = rangeMatches[1]; rangeI < rangeMatches[2]; ++rangeI) {
                            optionals.push({
                                altKey: keyCombo.altKey,
                                shiftKey: keyCombo.shiftKey,
                                metaKey: keyCombo.metaKey,
                                ctrlKey: keyCombo.ctrlKey,
                                keyCode: rangeI,
                                jwertyCombo: String(jwertyCodeFragment)
                            });

                        }
                        keyCombo.keyCode = rangeI;
                    // Inject either keyCode or ctrl/meta/shift/altKey into keyCombo
                    } else {
                        keyCombo.keyCode = 0;
                    }
                }
                optionals.push(keyCombo);

            }
            this[i] = optionals;
        }
        this.length = i;
        return this;
    }

    var jwerty = exports.jwerty = {
        /**
         * jwerty.event
         *
         * `jwerty.event` will return a function, which expects the first
         *  argument to be a key event. When the key event matches `jwertyCode`,
         *  `callbackFunction` is fired. `jwerty.event` is used by `jwerty.key`
         *  to bind the function it returns. `jwerty.event` is useful for
         *  attaching to your own event listeners. It can be used as a decorator
         *  method to encapsulate functionality that you only want to fire after
         *  a specific key combo. If `callbackContext` is specified then it will
         *  be supplied as `callbackFunction`'s context - in other words, the
         *  keyword `this` will be set to `callbackContext` inside the
         *  `callbackFunction` function.
         *
         *   @param {Mixed} jwertyCode can be an array, or string of key
         *      combinations, which includes optinals and or sequences
         *   @param {Function} callbackFucntion is a function (or boolean) which
         *      is fired when jwertyCode is matched. Return false to
         *      preventDefault()
         *   @param {Object} callbackContext (Optional) The context to call
         *      `callback` with (i.e this)
         *
         */
        event: function (jwertyCode, callbackFunction, callbackContext /*? this */) {

            // Construct a function out of callbackFunction, if it is a boolean.
            if (realTypeOf(callbackFunction, 'boolean')) {
                var bool = callbackFunction;
                callbackFunction = function () { return bool; };
            }

            jwertyCode = new JwertyCode(jwertyCode);

            // Initialise in-scope vars.
            var i = 0,
                c = jwertyCode.length - 1,
                returnValue,
                jwertyCodeIs;

            // This is the event listener function that gets returned...
            return function (event) {

                // if jwertyCodeIs returns truthy (string)...
                if ((jwertyCodeIs = jwerty.is(jwertyCode, event, i))) {
                    // ... and this isn't the last key in the sequence,
                    // incriment the key in sequence to check.
                    if (i < c) {
                        ++i;
                        return;
                    // ... and this is the last in the sequence (or the only
                    // one in sequence), then fire the callback
                    } else {
                        returnValue = callbackFunction.call(
                            callbackContext || this, event, jwertyCodeIs);

                        // If the callback returned false, then we should run
                        // preventDefault();
                        if (returnValue === false) event.preventDefault();

                        // Reset i for the next sequence to fire.
                        i = 0;
                        return;
                    }
                }

                // If the event didn't hit this time, we should reset i to 0,
                // that is, unless this combo was the first in the sequence,
                // in which case we should reset i to 1.
                i = jwerty.is(jwertyCode, event) ? 1 : 0;
            };
        },

        /**
         * jwerty.is
         *
         * `jwerty.is` will return a boolean value, based on if `event` matches
         *  `jwertyCode`. `jwerty.is` is called by `jwerty.event` to check
         *  whether or not to fire the callback. `event` can be a DOM event, or
         *  a jQuery/Zepto/Ender manufactured event. The properties of
         *  `jwertyCode` (speficially ctrlKey, altKey, metaKey, shiftKey and
         *  keyCode) should match `jwertyCode`'s properties - if they do, then
         *  `jwerty.is` will return `true`. If they don't, `jwerty.is` will
         *  return `false`.
         *
         *   @param {Mixed} jwertyCode can be an array, or string of key
         *      combinations, which includes optinals and or sequences
         *   @param {KeyboardEvent} event is the KeyboardEvent to assert against
         *   @param {Integer} i (Optional) checks the `i` key in jwertyCode
         *      sequence
         *
         */
        is: function (jwertyCode, event, i /*? 0*/) {
            jwertyCode = new JwertyCode(jwertyCode);
            // Default `i` to 0
            i = i || 0;
            // We are only interested in `i` of jwertyCode;
            jwertyCode = jwertyCode[i];
            // jQuery stores the *real* event in `originalEvent`, which we use
            // because it does annoything stuff to `metaKey`
            event = event.originalEvent || event;

            // We'll look at each optional in this jwertyCode sequence...
            var n = jwertyCode.length,
                returnValue = false;

            // Loop through each fragment of jwertyCode
            while (n--) {
                returnValue = jwertyCode[n].jwertyCombo;
                // For each property in the jwertyCode object, compare to `event`
                for (var p in jwertyCode[n]) {
                    // ...except for jwertyCode.jwertyCombo...
                    if (p !== 'jwertyCombo' && event[p] != jwertyCode[n][p]) returnValue = false;
                }
                // If this jwertyCode optional wasn't falsey, then we can return early.
                if (returnValue !== false) return returnValue;
            }
            return returnValue;
        },

        /**
         * jwerty.key
         *
         *  `jwerty.key` will attach an event listener and fire
         *   `callbackFunction` when `jwertyCode` matches. The event listener is
         *   attached to `document`, meaning it will listen for any key events
         *   on the page (a global shortcut listener). If `callbackContext` is
         *   specified then it will be supplied as `callbackFunction`'s context
         *   - in other words, the keyword `this` will be set to
         *   `callbackContext` inside the `callbackFunction` function.
         *   returns a subscription handle `h`, by which you may undo the binding
         *   by calling `h.unbind()`
         *
         *   @param {Mixed} jwertyCode can be an array, or string of key
         *      combinations, which includes optinals and or sequences
         *   @param {Function} callbackFunction is a function (or boolean) which
         *      is fired when jwertyCode is matched. Return false to
         *      preventDefault()
         *   @param {Object} callbackContext (Optional) The context to call
         *      `callback` with (i.e this)
         *   @param {Mixed} selector can be a string, jQuery/Zepto/Ender object,
         *      or an HTML*Element on which to bind the eventListener
         *   @param {Mixed} selectorContext can be a string, jQuery/Zepto/Ender
         *      object, or an HTML*Element on which to scope the selector
         *
         */
        key: function (jwertyCode, callbackFunction, callbackContext /*? this */, selector /*? document */, selectorContext /*? body */) {
            // Because callbackContext is optional, we should check if the
            // `callbackContext` is a string or element, and if it is, then the
            // function was called without a context, and `callbackContext` is
            // actually `selector`
            var realSelector = realTypeOf(callbackContext, 'element') || realTypeOf(callbackContext, 'string') ? callbackContext : selector,
            // If `callbackContext` is undefined, or if we skipped it (and
            // therefore it is `realSelector`), set context to `global`.
                realcallbackContext = realSelector === callbackContext ? global : callbackContext,
            // Finally if we did skip `callbackContext`, then shift
            // `selectorContext` to the left (take it from `selector`)
                realSelectorContext = realSelector === callbackContext ? selector : selectorContext;

            // If `realSelector` is already a jQuery/Zepto/Ender/DOM element,
            // then just use it neat, otherwise find it in DOM using $$()
            var element = realTypeOf(realSelector, 'element') ? realSelector : $$(realSelector, realSelectorContext);
            var callback = jwerty.event(jwertyCode, callbackFunction, realcallbackContext);
            $b( element, callback );

            return {unbind:function(){ $u( element, callback ) }};
        },

        /**
         * jwerty.fire
         *
         * `jwerty.fire` will construct a keyup event to fire, based on
         *  `jwertyCode`. The event will be fired against `selector`.
         *  `selectorContext` is used to search for `selector` within
         *  `selectorContext`, similar to jQuery's
         *  `$('selector', 'context')`.
         *
         *   @param {Mixed} jwertyCode can be an array, or string of key
         *      combinations, which includes optinals and or sequences
         *   @param {Mixed} selector can be a string, jQuery/Zepto/Ender object,
         *      or an HTML*Element on which to bind the eventListener
         *   @param {Mixed} selectorContext can be a string, jQuery/Zepto/Ender
         *      object, or an HTML*Element on which to scope the selector
         *
         */
        fire: function (jwertyCode, selector /*? document */, selectorContext /*? body */, i) {
            jwertyCode = new JwertyCode(jwertyCode);
            var realI = realTypeOf(selectorContext, 'number') ? selectorContext : i;

            // If `realSelector` is already a jQuery/Zepto/Ender/DOM element,
            // then just use it neat, otherwise find it in DOM using $$()
            $f(
                realTypeOf(selector, 'element') ? selector : $$(selector, selectorContext),
                jwertyCode[realI || 0][0]
            );
        },

        KEYS: _keys
    };

}(typeof global !== 'undefined' && global.window || this, (typeof module !== 'undefined' && module.exports ? module.exports : this)));
