document.addEventListener('DOMContentLoaded', () => {

    //===
    // VARIABLES
    //===
    const EVENTS = ['i-click', 'i-view', 'i-scroll-up', 'i-scroll-down', 'i-hover'];
    const FUNCTION_TREE = {
        'class': ['add', 'remove', 'toggle']
    };
    let elementsValidates = [];

    //===
    // FUNCTIONS
    //===

    /**
     * Method that validates syntax and reports.
     * return - Bool
     */
    function validateSyntax() {
        elementsValidates = [];
        // Check all event syntax
        return EVENTS.map((event) => {
            // Check element FUNCTION_TREE
            return [...document.querySelectorAll(`[${event}]`)].map((element) => {
                // Check KEY FUNCTION_TREE
                let checked = Object.keys(FUNCTION_TREE).map((key) => {
                    // Check METHODS FUNCTION_TREE
                    return FUNCTION_TREE[key].map((method) => {
                        return RegExp(`^${key}:${method}\\('\\w+', *'[#,.,a-zA-Z]\\w*'\\)$`).test(element.getAttribute(event));
                    }).some(method => method);
                }).every(key => key);
                if(checked) {
                    // Save element validate
                    elementsValidates.push(element);
                } else {
                    // Notify error
                    console.error('FFNM: Bad syntax');
                    console.error(element);
                }
                return checked;
            }).every(item => item);
        }).every(event => event);
    }

    /**
     * Method add events click
     * return void
     */
    function addEventClick() {
    }


    //===
    // INIT
    //===
    validateSyntax();


});