"use strict";

/**
 * 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() {
    /**
     * @param {string} c
     * @return {boolean}
     **/
    function isAlphadec(c) {
        return ((c >= 'A' && c <= 'Z') ||
            (c >= 'a' && c <= 'z') ||
            (c >= '0' && c <= '9') ||
            "àèìòùÀÈÌÒÙáéíóúýÁÉÍÓÚÝâêîôûÂÊÎÔÛãñõÃÑÕäëïöüÿÄËÏÖÜŸçÇßØøÅåÆæœ".indexOf(c) !== -1);

    }

    /**
     * @constructor
     * @param {MsgBranch!} _parent
    **/
    function MsgTextLeaf(_parent) {
        /** @type {string} */
        this.text = "";

        /** @const @type {MsgBranch} */
        this._parent = _parent;
    }

    /**
     * @constructor
     * @param {MsgBranch|MsgTree} _parent
     * @param {number} triggerIndex
     * @param {string=} trigger
     */
    function MsgBranch(_parent, triggerIndex, trigger) {
        /** @const @type {number} */
        this.triggerIndex = triggerIndex;

        /** @type {MsgBranch|MsgTextLeaf} */
        this.lastNode = new MsgTextLeaf(this);

        /** @type {Array<MsgBranch|MsgTextLeaf>} */
        this.subNodes = [ this.lastNode ];

        /** @const @type {string} */
        this.trigger = trigger || '';

        /** @type {boolean} */
        this.isLink = this.trigger === '<';

        /** @type {boolean} */
        this.isBold = this.trigger === '*';

        /** @type {boolean} */
        this.isItalic = this.trigger === '_';

        /** @type {boolean} */
        this.isStrike = this.trigger === '~' || this.trigger === '-';

        /** @type {boolean} */
        this.isQuote = this.trigger === '>';

        /** @type {boolean} */
        this.isEmoji = this.trigger === ':';

        /** @type {boolean} */
        this.isCode = this.trigger === '`';

        /** @type {boolean} */
        this.isCodeBlock = this.trigger === '```';

        /** @type {boolean} */
        this.isEol = this.trigger === '\n';

        /** @const @type {MsgBranch|MsgTree} */
        this._parent = _parent;

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

    /** @return {boolean} */
    MsgBranch.prototype.checkIsBold = function() {
        return (this.isBold && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsBold());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsItalic = function() {
        return (this.isItalic && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsItalic());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsStrike = function() {
        return (this.isStrike && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsStrike());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsQuote = function() {
        return (this.isQuote && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsQuote());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsEmoji = function() {
        return (this.isEmoji && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsEmoji());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsCode = function() {
        return (this.isCode && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsCode());
    };

    /** @return {boolean} */
    MsgBranch.prototype.checkIsCodeBlock = function() {
        return (this.isCodeBlock && this.terminated) || (this._parent instanceof MsgBranch && this._parent.checkIsCodeBlock());
    };

    /**
     * Check if this token closes the branch
     * FIXME it is possible that an inner branch still lives
     * In this case, finishWith should return the new leave
     * Exemple: `_text *bold_ bold continue*` should be
     * + root
     * | italic
     *   | "text"
     *   | bold
     *     | "bold"
     * | bold
     *   | "bold continue"
     * and this function will return a "bold" branch
     *
     * @param {string} str
     * @param {number} i
     * @return {MsgTextLeaf|MsgBranch|null}
    **/
    MsgBranch.prototype.finishWith = function(str, i) {
        if (this.trigger === '<' && str[i] === '>') {
            return new MsgTextLeaf(/** @type {MsgBranch!} */ (this._parent));
        }
        if (str.substr(i, this.trigger.length) === this.trigger) {
            return new MsgTextLeaf(/** @type {MsgBranch!} */ (this._parent));
        }
        // FIXME
        // check if branch terminates here
        // If yes return a branche containing all unfinished children
        // If yes but no children, return a new MsgTextLeaf
        // If not return null
        return null;
    };

    /**
     * Check if this token is compatible with this branch
     * @param {string} str
     * @param {number} i
     * @return {boolean}
    **/
    MsgBranch.prototype.isAcceptable = function(str, i) {
        if (this.isEmoji && (str[i] === ' ' || str[i] === '\t'))
            return false;
        return true;
    };

    /**
     * Check if str[i] is a trigger for a new node
     * if true, return the trigger
     * @param {string} str
     * @param {number} i
     * @return {string|null}
    **/
    MsgBranch.prototype.isNewToken = function(str, i) {
        if (this.lastNode instanceof MsgTextLeaf) {
            if (str.substr(i, 3) === '```')
                return '```';
            if ('`' === str[i])
                return str[i];
            if (['*', '~', '-', '_' ].indexOf(str[i]) !== -1 && (isAlphadec(str[i +1]) || ['*', '`', '~', '-', '_', ':', '<'].indexOf(str[i+1]) !== -1))
                return str[i];
            if ([':', '<'].indexOf(str[i]) !== -1 && isAlphadec(str[i +1]))
                return str[i];
        }
        return null;
    };

    /** @return {number} */
    MsgTextLeaf.prototype.addChar = function(str, i) {
        this.text += str[i];
        return 1;
    };

    /**
     * Parse next char
     * @param {string} str
     * @param {number} i
     * @return {number}
    **/
    MsgBranch.prototype.addChar = function(str, i) {
        var isFinished = this.lastNode.finishWith ? this.lastNode.finishWith(str, i) : null;

        if (isFinished) {
            // terminated token, move pointer to a new leaf
            this.lastNode.terminated = true;
            this.lastNode = isFinished;
            this.subNodes.push(isFinished);
            return 1;
        } else {
            if (this.lastNode instanceof MsgTextLeaf || this.lastNode.isAcceptable(str, i)) {
                var isNewToken = this.isNewToken(str, i);
                if (isNewToken) {
                    this.lastNode = new MsgBranch(this, i, isNewToken);
                    this.subNodes.push(this.lastNode);
                    return this.lastNode.trigger.length;
                } else {
                    return this.lastNode.addChar(str, i);
                }
            } else {
                // last branch child is not compatible with this token.
                // So, lastBranch is not a branch
                // Add a new "escaped" node to replace trigger
                var textNode = new MsgTextLeaf(this);
                textNode.addChar(str, this.lastNode.trigger);
                this.subNodes.pop();
                this.subNodes.push(textNode);

                // new root
                var newBranch = new MsgBranch(this, this.lastNode.triggerIndex +1);
                for (var charIndex = this.lastNode.triggerIndex +1; charIndex <= i;)
                    charIndex += newBranch.addChar(str, charIndex);
                this.lastNode = this.subNodes[this.subNodes.length -1];
                return 1;
            }
        }
    };

    /**
     * @return {boolean} true if still contains stuff
    **/
    MsgBranch.prototype.prune = function() {
        var branches = [];
        this.subNodes.forEach(function(i) {
            if (i instanceof MsgTextLeaf) {
                if (i.text !== '')
                    branches.push(i);
            } else if (i.prune()) {
                branches.push(i);
            }
        });
        this.subNodes = branches;
        this.lastNode = branches[branches.length -1];
        return !!this.subNodes.length;
    };

    /**
     * @return {string}
    **/
    MsgTextLeaf.prototype.innerHTML = function() {
        return this.text;
    };

    /**
     * @return {string}
    **/
    MsgTextLeaf.prototype.outerHTML = function() {
        var tagName = 'span'
            ,classList = [];

        if (this._parent.checkIsCodeBlock()) {
            classList.push('codeblock');
        } else if (this._parent.checkIsCode()) {
            classList.push('code');
        } else {
            if (this.isLink)
                tagName = 'a';
            if (this._parent.checkIsBold())
                classList.push('bold');
            if (this._parent.checkIsItalic())
                classList.push('italic');
            if (this._parent.checkIsStrike())
                classList.push('strike');
            if (this._parent.checkIsQuote()) // FIXME nope.
                classList.push('quote');
            if (this._parent.checkIsEmoji())
                classList.push('emoji');
        }
        return '<' +tagName +(classList.length ? ' class="' +classList.join(' ') +'"' : '') +'>' +this.innerHTML() +'</' +tagName +'>';
    };

    MsgBranch.prototype.outerHTML = function() {
        var html = "";

        this.subNodes.forEach(function(node) {
            html += node.outerHTML();
        });
        return html;
    };

    MsgBranch.prototype.eof = function() {
        // FIXME check for any unterminated branches to reinterpret them
    };

    /**
     * @constructor
     * @param {string} text
     */
    function MsgTree(text) {
        /** @const @type {string} */
        this.text = text;

        /** @type {MsgBranch|null} */
        this.root = null;
    }

    MsgTree.prototype.parse = function() {
        this.root = new MsgBranch(this, 0);
        for (var i =0, textLen = this.text.length; i < textLen;)
            i += this.root.addChar(this.text, i);
        this.root.eof();
        if (!this.root.prune()) {
            this.root = null;
        }
    };

    /**
     * @return {string}
    **/
    MsgTree.prototype.toHTML = function() {
        return this.root ? this.root.outerHTML() : "";
    };

    return function(text) {
        var root = new MsgTree(text);
        root.parse();
        return (root.toHTML());
    };
})();