/**
 * replace all :emoji: codes with corresponding image
 * @param {string} inputString
 * @return {string}
**/
function formatEmojis(inputString) {
    return inputString.replace(/:([^ \t:]+):/g, function(returnFailed, emoji) {
        var emojiDom = makeEmojiDom(emoji);
        if (emojiDom) {
            var domParent = document.createElement("span");
            domParent.className = returnFailed === inputString ? R.klass.emoji.medium : R.klass.emoji.small;
            domParent.appendChild(emojiDom);
            return domParent.outerHTML;
        }
        return returnFailed;
    });
}

/** @type {function(string):string} */
var formatText = (function() {
    /**
     * @constructor
     * @param {string} fullText
     */
    function MessagePart(fullText) {
        /** @type {Array.<MessagePart>} */
        this.subParts = [];

        /** @type {string} */
        this.text = "";

        /** @type {string} */
        this.fullText = fullText;

        /** @type {boolean} */
        this.italic = false;

        /** @type {boolean} */
        this.bold = false;

        /** @type {boolean} */
        this.strike = false;

        /** @type {boolean} */
        this.code = false;

        /** @type {boolean} */
        this.longCode = false;

        /** @type {boolean} */
        this.quote = false;
    }

    var isAlphadec = function(c) {
        return ((c >= 'A' && c <= 'Z') ||
            (c >= 'a' && c <= 'z') ||
            (c >= '0' && c <= '9') ||
            "àèìòùÀÈÌÒÙáéíóúýÁÉÍÓÚÝâêîôûÂÊÎÔÛãñõÃÑÕäëïöüÿÄËÏÖÜŸçÇßØøÅåÆæœ".indexOf(c) !== -1);
    }
    ,checkEnd = function(str, pos, c) {
        while (str[pos]) {
            if (isAlphadec(str[pos]) && str[pos] != c && str[pos +1] == c) {
                return true;
            }
            pos++;
        }
        return false;
    }

    MessagePart.prototype.isFinished = function() {
        var result = false;
        if (this.longCode)
            return this.text.substr(this.text.length -3) === '```';
        if (this.code)
            return this.text[this.text.length -1] === '`' && this.text.length > 1;
        if (this.bold)
            result |= this.text[this.text.length -1] === '*' && this.text.length > 1;
        if (this.strike)
            result |= this.text[this.text.length -1] === '~' && this.text.length > 1;
        if (this.italic)
            result |= this.text[this.text.length -1] === '_' && this.text.length > 1;
        if (this.quote)
            result |= this.text[this.text.length -1] === '\n';
        return result || this.isOnlyText();
    };

    MessagePart.prototype.addChar = function(c) {
        this.text += c;
        return this;
    };

    MessagePart.prototype.isOnlyText = function() {
        return !this.italic &&
            !this.bold &&
            !this.strike &&
            !this.code &&
            !this.longCode &&
            !this.quote;
    };

    /**
     * @return {MessagePart}
    **/
    MessagePart.prototype.finalize = function() {
        if (this.longCode)
            this.text = this.text.substr(0, this.text.length -3);
        else if (this.code)
            this.text = this.text.substr(0, this.text.length -1);
        else if (this.bold)
            this.text = this.text.substr(0, this.text.length -1);
        else if (this.strike)
            this.text = this.text.substr(0, this.text.length -1);
        else if (this.italic)
            this.text = this.text.substr(0, this.text.length -1);
        else if (this.quote)
            this.text = this.text.substr(0, this.text.length -1);
        return this;
    };

    MessagePart.prototype.cloneType = function() {
        var clone = new MessagePart(this.fullText);
        clone.italic = this.italic;
        clone.bold = this.bold;
        clone.strike = this.strike;
        clone.code = this.code;
        clone.longCode = this.longCode;
        clone.quote = this.quote;
        return clone;
    };

    /**
     * @param {boolean=} skipFirst
    **/
    MessagePart.prototype.formatText = function(skipFirst) {
        var lastChild = new MessagePart(this.fullText);

        for (var i =skipFirst === true ? 1 : 0, textLength =this.fullText.length; i < textLength; i++) {
            //First, check if we have a ``` code block
            if (!lastChild.longCode && this.fullText.substr(i, 3) === '```') {
                this.subParts.push(lastChild.finalize());
                lastChild = new MessagePart(this.fullText.substr(i));
                lastChild.longCode = true;
                i += 2;
            } else if (!lastChild.longCode && !lastChild.code && this.fullText[i] === '`') {
                this.subParts.push(lastChild.finalize());
                lastChild = new MessagePart(this.fullText.substr(i));
                lastChild.code = true;
            } else if (!lastChild.longCode && !lastChild.italic && this.fullText[i] === '_') {
                this.subParts.push(lastChild.finalize());
                lastChild = new MessagePart(this.fullText.substr(i));
                lastChild.italic = true;
            } else if (!lastChild.longCode && !lastChild.bold && this.fullText[i] === '*') {
                this.subParts.push(lastChild.finalize());
                lastChild = new MessagePart(this.fullText.substr(i));
                lastChild.bold = true;
            } else if (!lastChild.longCode && !lastChild.strike && this.fullText[i] === '~') {
                this.subParts.push(lastChild.finalize());
                lastChild = new MessagePart(this.fullText.substr(i));
                lastChild.strike = true;
            } else {
                lastChild.addChar(this.fullText[i]);
                if (!lastChild.isOnlyText() && lastChild.isFinished()) {
                    this.subParts.push(lastChild.finalize());
                    lastChild = new MessagePart(this.fullText.substr(i +1));
                }
            }
        }
        if (lastChild.isFinished()) {
            this.subParts.push(lastChild.finalize());
        } else {
            // Unterminated sequence
            var textChild = new MessagePart(lastChild.fullText[0]);
            textChild.text = lastChild.fullText[0];
            this.subParts.push(textChild.finalize());
            lastChild.formatText(true);
            this.subParts.push(lastChild);
        }
        /*
        var _msgContent = ""
            ,currentMods = {}
            ,quote = false
            ,i =0

        var msgContent = this.text.replace(new RegExp('<([@#]?)([^>]*)>', 'g'),
            function(matched, type, entity) {
                var sub = entity.split('|');

                if (type === '@') {
                    if (!sub[1]) {
                        var user = SLACK.context.users[sub[0]];
                        sub[1] = user ? ('@' +user.name) : locale.unknownMember;
                    } else if ('@' !== sub[1][0]) {
                        sub[1] = '@' +sub[1];
                    }
                    sub[0] = '#' +sub[0];
                    sub[2] = R.klass.msg.link +' ' +R.klass.msg.linkuser;
                } else if (type === '#') {
                    if (!sub[1]) {
                        var chan = SLACK.context.channels[sub[0]];
                        sub[1] = chan ? ('#' +chan.name) : locale.unknownChannel;
                    } else if ('#' !== sub[1][0]) {
                        sub[1] = '#' +sub[1];
                    }
                    sub[0] = '#' +sub[0];
                    sub[2] = R.klass.msg.link +' ' +R.klass.msg.linkchan;
                } else if (sub[0].indexOf("://") !== -1) {
                    if (!sub[1])
                        sub[1] = sub[0];
                    sub[2] = R.klass.msg.link;
                } else {
                    return matched;
                }
                return '<a href="' +sub[0] +'" class="' +sub[2] +'"' +(!type ? ' target="_blank"' : '') +'>' +sub[1] +'</a>';
            });
        msgContent = formatEmojis(msgContent);
        var msgLength = msgContent.length,
            appendMod = function(mods) {
                if (!Object.keys(currentMods).length)
                    return "";
                return '<span class="' +Object.keys(mods).join(' ') +'">';
            };

        // Skip trailing
        while (i < msgLength && (msgContent[i] === ' ' || msgContent[i] === '\t'))
            i++;
        if (msgContent.substr(i, 4) === '&gt;') {
            quote = true;
            i += 4;
        }
        for (; i < msgLength; i++) {
            var c = msgContent[i];

            if (c === '<') {
                do {
                    _msgContent += msgContent[i++];
                } while (msgContent[i -1] !== '>' && msgContent[i]);
                i--;
                continue;
            }
            if (!(currentMods[R.klass.msg.style.bold]) && c === '*' && msgContent[i +1] && checkEnd(msgContent, i, c)) {
                if (Object.keys(currentMods).length)
                    _msgContent += '</span>';
                currentMods[R.klass.msg.style.bold] = true;
                _msgContent += appendMod(currentMods);
            } else if (!(currentMods[R.klass.msg.style.strike]) && c === '~' && msgContent[i +1] && checkEnd(msgContent, i, c)) {
                if (Object.keys(currentMods).length)
                    _msgContent += '</span>';
                currentMods[R.klass.msg.style.strike] = true;
                _msgContent += appendMod(currentMods);
            } else if (!(currentMods[R.klass.msg.style.code]) && c === '`' && msgContent[i +1] && checkEnd(msgContent, i, c)) {
                if (Object.keys(currentMods).length)
                    _msgContent += '</span>';
                currentMods[R.klass.msg.style.code] = true;
                _msgContent += appendMod(currentMods);
            } else if (!(currentMods[R.klass.msg.style.italic]) && c === '_' && msgContent[i +1] && checkEnd(msgContent, i, c)) {
                if (Object.keys(currentMods).length)
                    _msgContent += '</span>';
                currentMods[R.klass.msg.style.italic] = true;
                _msgContent += appendMod(currentMods);
            } else {
                var finalFound = false;
                _msgContent += c;

                do {
                    if ((currentMods[R.klass.msg.style.bold]) && c !== '*' && msgContent[i +1] === '*') {
                        delete currentMods[R.klass.msg.style.bold];
                        finalFound = true;
                    } else if ((currentMods[R.klass.msg.style.strike]) && c !== '~' && msgContent[i +1] === '~') {
                        delete currentMods[R.klass.msg.style.strike];
                        finalFound = true;
                    } else if ((currentMods[R.klass.msg.style.code]) && c !== '`' && msgContent[i +1] === '`') {
                        delete currentMods[R.klass.msg.style.code];
                        finalFound = true;
                    } else if ((currentMods[R.klass.msg.style.italic]) && c !== '_' && msgContent[i +1] === '_') {
                        delete currentMods[R.klass.msg.style.italic];
                        finalFound = true;
                    } else {
                        break;
                    }
                    c = msgContent[++i];
                } while (i < msgLength);
                if (finalFound)
                    _msgContent += '</span>' +appendMod(currentMods);
            }
        }
        if (!isObjectEmpty(currentMods)) {
            // Should not append
            console.warn("formatter warning");
            _msgContent += '</span>';
        }
        /*
        if (quote)
            msgContents[msgContentIndex] = '<span class="' +R.klass.msg.style.quote +'">' +_msgContent +'</span>';
        else
            msgContents[msgContentIndex] = _msgContent;
        */
    };

    MessagePart.prototype.getOuterClass = function() {
        var classList = '';

        if (this.longCode) {
            classList += ' ' +R.klass.msg.style.longCode;
        }
        if (this.bold) {
            classList += ' ' +R.klass.msg.style.bold;
        }
        if (this.code) {
            classList += ' ' +R.klass.msg.style.code;
        }
        if (this.italic) {
            classList += ' ' +R.klass.msg.style.italic;
        }
        if (this.strike) {
            classList += ' ' +R.klass.msg.style.strike;
        }
        if (this.quote) {
            classList += ' ' +R.klass.msg.style.quote;
        }
        return classList;
    };

    /** @return {string} */
    MessagePart.prototype.getInnerHTML = function() {
        return this.text
            .replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, '&nbsp;') // replace trailing spaces par non-secable spaces
            .replace(/\n/g, '<br/>');
    };

    /** @return {string} */
    MessagePart.prototype.toHTML = function() {
        if (this.subParts.length) {
            var result = "";
            this.subParts.forEach(function(part) {
                result += part.toHTML();
            });
            return result;
        } else {
            if (this.isOnlyText() && !this.text.length)
                return "";
            return '<span class="' +this.getOuterClass() +'">' +this.getInnerHTML() +'</span>';
        }
    };

    return function (fullText) {
        // trivial empty string
        var text = (fullText || "").trim();
        if (text == "")
            return "";

        var msgContent = new MessagePart(text);
        msgContent.formatText();
        console.log(msgContent);
        return msgContent.toHTML();
    }
})();