/**
 * Simple, lightweight, usable local autocomplete library for modern browsers
 * Because there weren’t enough autocomplete scripts in the world? Because I’m completely insane and have NIH syndrome? Probably both. :P
 * @author Lea Verou http://leaverou.github.io/awesomplete
 * MIT license
 */

(function () {

    var _ = function (input, o) {
        var me = this;

        // Setup

        this.isOpened = false;

        this.input = $(input);
        this.input.setAttribute("autocomplete", "off");
        this.input.setAttribute("aria-autocomplete", "list");

        o = o || {};

        configure(this, {
            minChars: 2,
            maxItems: 10,
            autoFirst: false,
            data: _.DATA,
            filter: _.FILTER_CONTAINS,
            sort: _.SORT_BYLENGTH,
            item: _.ITEM,
            replace: _.REPLACE
        }, o);

        this.index = -1;

        // Create necessary elements

        this.container = $.create("div", {
            className: "awesomplete",
            around: input
        });

        this.ul = $.create("ul", {
            hidden: "hidden",
            inside: this.container
        });

        this.status = $.create("span", {
            className: "visually-hidden",
            role: "status",
            "aria-live": "assertive",
            "aria-relevant": "additions",
            inside: this.container
        });

        // Bind events

        $.bind(this.input, {
            "input": this.evaluate.bind(this),
            "blur": this.close.bind(this, { reason: "blur" }),
            "keydown": function(evt) {
                var c = evt.keyCode;

                // If the dropdown `ul` is in view, then act on keydown for the following keys:
                // Enter / Esc / Up / Down
                if(me.opened) {
                    if (c === 13 && me.selected) { // Enter
                        evt.preventDefault();
                        me.select();
                    }
                    else if (c === 27) { // Esc
                        me.close({ reason: "esc" });
                    }
                    else if (c === 38 || c === 40) { // Down/Up arrow
                        evt.preventDefault();
                        me[c === 38? "previous" : "next"]();
                    }
                }
            }
        });

        $.bind(this.input.form, {"submit": this.close.bind(this, { reason: "submit" })});

        $.bind(this.ul, {"mousedown": function(evt) {
            var li = evt.target;

            if (li !== this) {

                while (li && !/li/i.test(li.nodeName)) {
                    li = li.parentNode;
                }

                if (li && evt.button === 0) {  // Only select on left click
                    evt.preventDefault();
                    me.select(li, evt.target);
                }
            }
        }});

        if (this.input.hasAttribute("list")) {
            this.list = "#" + this.input.getAttribute("list");
            this.input.removeAttribute("list");
        }
        else {
            this.list = this.input.getAttribute("data-list") || o.list || [];
        }

        _.all.push(this);
    };

    _.prototype = {
        set list(list) {
            if (Array.isArray(list)) {
                this._list = list;
            }
            else if (typeof list === "string" && list.indexOf(",") > -1) {
                this._list = list.split(/\s*,\s*/);
            }
            else { // Element or CSS selector
                list = $(list);

                if (list && list.children) {
                    var items = [];
                    slice.apply(list.children).forEach(function (el) {
                        if (!el.disabled) {
                            var text = el.textContent.trim();
                            var value = el.value || text;
                            var label = el.label || text;
                            if (value !== "") {
                                items.push({ label: label, value: value });
                            }
                        }
                    });
                    this._list = items;
                }
            }

            if (document.activeElement === this.input) {
                this.evaluate();
            }
        },

        get selected() {
            return this.index > -1;
        },

        get opened() {
            return this.isOpened;
        },

        close: function (o) {
            if (!this.opened) {
                return;
            }

            this.ul.setAttribute("hidden", "");
            this.isOpened = false;
            this.index = -1;

            $.fire(this.input, "awesomplete-close", o || {});
        },

        open: function () {
            this.ul.removeAttribute("hidden");
            this.isOpened = true;

            if (this.autoFirst && this.index === -1) {
                this.goto(0);
            }

            $.fire(this.input, "awesomplete-open");
        },

        next: function () {
            var count = this.ul.children.length;
            this.goto(this.index < count - 1 ? this.index + 1 : (count ? 0 : -1) );
        },

        previous: function () {
            var count = this.ul.children.length;
            var pos = this.index - 1;

            this.goto(this.selected && pos !== -1 ? pos : count - 1);
        },

        // Should not be used, highlights specific item without any checks!
        goto: function (i) {
            var lis = this.ul.children;

            if (this.selected) {
                lis[this.index].setAttribute("aria-selected", "false");
            }

            this.index = i;

            if (i > -1 && lis.length > 0) {
                lis[i].setAttribute("aria-selected", "true");
                this.status.textContent = lis[i].textContent;

                // scroll to highlighted element in case parent's height is fixed
                this.ul.scrollTop = lis[i].offsetTop - this.ul.clientHeight + lis[i].clientHeight;

                $.fire(this.input, "awesomplete-highlight", {
                    text: this.suggestions[this.index]
                });
            }
        },

        select: function (selected, origin) {
            if (selected) {
                this.index = $.siblingIndex(selected);
            } else {
                selected = this.ul.children[this.index];
            }

            if (selected) {
                var suggestion = this.suggestions[this.index];

                var allowed = $.fire(this.input, "awesomplete-select", {
                    text: suggestion,
                    origin: origin || selected
                });

                if (allowed) {
                    this.replace(suggestion);
                    this.close({ reason: "select" });
                    $.fire(this.input, "awesomplete-selectcomplete", {
                        text: suggestion
                    });
                }
            }
        },

        evaluate: function() {
            var me = this;
            var value = this.input.value;

            if (value.length >= this.minChars && this._list.length > 0) {
                this.index = -1;
                // Populate list with options that match
                this.ul.innerHTML = "";

                this.suggestions = this._list
                    .map(function(item) {
                        return new Suggestion(me.data(item, value));
                    })
                    .filter(function(item) {
                        return me.filter(item, value);
                    })
                    .sort(this.sort)
                    .slice(0, this.maxItems);

                this.suggestions.forEach(function(text) {
                    me.ul.appendChild(me.item(text, value));
                });

                if (this.ul.children.length === 0) {
                    this.close({ reason: "nomatches" });
                } else {
                    this.open();
                }
            }
            else {
                this.close({ reason: "nomatches" });
            }
        }
    };

// Static methods/properties

    _.all = [];

    _.FILTER_CONTAINS = function (text, input) {
        return RegExp($.regExpEscape(input.trim()), "i").test(text);
    };

    _.FILTER_STARTSWITH = function (text, input) {
        return RegExp("^" + $.regExpEscape(input.trim()), "i").test(text);
    };

    _.SORT_BYLENGTH = function (a, b) {
        if (a.length !== b.length) {
            return a.length - b.length;
        }

        return a < b? -1 : 1;
    };

    _.ITEM = function (text, input) {
        var html = input.trim() === '' ? text : text.replace(RegExp($.regExpEscape(input.trim()), "gi"), "<mark>$&</mark>");
        return $.create("li", {
            innerHTML: html,
            "aria-selected": "false"
        });
    };

    _.REPLACE = function (text) {
        this.input.value = text.value;
    };

    _.DATA = function (item/*, input*/) { return item; };

// Private functions

    function Suggestion(data) {
        var o = Array.isArray(data)
            ? { label: data[0], value: data[1] }
            : typeof data === "object" && "label" in data && "value" in data ? data : { label: data, value: data };

        this.label = o.label || o.value;
        this.value = o.value;
    }
    Object.defineProperty(Suggestion.prototype = Object.create(String.prototype), "length", {
        get: function() { return this.label.length; }
    });
    Suggestion.prototype.toString = Suggestion.prototype.valueOf = function () {
        return "" + this.label;
    };

    function configure(instance, properties, o) {
        for (var i in properties) {
            var initial = properties[i],
                attrValue = instance.input.getAttribute("data-" + i.toLowerCase());

            if (typeof initial === "number") {
                instance[i] = parseInt(attrValue);
            }
            else if (initial === false) { // Boolean options must be false by default anyway
                instance[i] = attrValue !== null;
            }
            else if (initial instanceof Function) {
                instance[i] = null;
            }
            else {
                instance[i] = attrValue;
            }

            if (!instance[i] && instance[i] !== 0) {
                instance[i] = (i in o)? o[i] : initial;
            }
        }
    }

// Helpers

    var slice = Array.prototype.slice;

    function $(expr, con) {
        return typeof expr === "string"? (con || document).querySelector(expr) : expr || null;
    }

    function $$(expr, con) {
        return slice.call((con || document).querySelectorAll(expr));
    }

    $.create = function(tag, o) {
        var element = document.createElement(tag);

        for (var i in o) {
            var val = o[i];

            if (i === "inside") {
                $(val).appendChild(element);
            }
            else if (i === "around") {
                var ref = $(val);
                ref.parentNode.insertBefore(element, ref);
                element.appendChild(ref);
            }
            else if (i in element) {
                element[i] = val;
            }
            else {
                element.setAttribute(i, val);
            }
        }

        return element;
    };

    $.bind = function(element, o) {
        if (element) {
            for (var event in o) {
                var callback = o[event];

                event.split(/\s+/).forEach(function (event) {
                    element.addEventListener(event, callback);
                });
            }
        }
    };

    $.fire = function(target, type, properties) {
        var evt = document.createEvent("HTMLEvents");

        evt.initEvent(type, true, true );

        for (var j in properties) {
            evt[j] = properties[j];
        }

        return target.dispatchEvent(evt);
    };

    $.regExpEscape = function (s) {
        return s.replace(/[-\\^$*+?.()|[\]{}]/g, "\\$&");
    };

    $.siblingIndex = function (el) {
        /* eslint-disable no-cond-assign */
        for (var i = 0; el = el.previousElementSibling; i++);
        return i;
    };

// Initialization

    function init() {
        $$("input.awesomplete").forEach(function (input) {
            new _(input);
        });
    }

// Are we in a browser? Check for Document constructor
    if (typeof Document !== "undefined") {
        // DOM already loaded?
        if (document.readyState !== "loading") {
            init();
        }
        else {
            // Wait for it
            document.addEventListener("DOMContentLoaded", init);
        }
    }

    _.$ = $;
    _.$$ = $$;

// Make sure to export Awesomplete on self when in a browser
    if (typeof self !== "undefined") {
        self.Awesomplete = _;
    }

// Expose Awesomplete as a CJS module
    if (typeof module === "object" && module.exports) {
        module.exports = _;
    }

    return _;

}());