SpontaneousCMS/spontaneous

Spontaneous.Require = {
    pending: [],
    current: false,
    _completed: [],
    position: 0,
    async: true,
    init: function(asynchronous) {
        this.async = asynchronous;
        var body = document.body;
        var splash = document.createElement('div');
        splash.id = 'script-load-splash';
            var progress_outer = document.createElement('div');
            progress_outer.id = 'script-load-progress';
        if (this.async) {
            var progress_inner = document.createElement('div');
            progress_outer.appendChild(progress_inner);
            this.bar = progress_inner;
            this.progress(0);
        } else {
            progress_outer.className = 'synchronous';
            progress_outer.innerHTML = 'Loading...';
        }
        splash.appendChild(progress_outer);
        body.appendChild(splash);
        this.container = splash;
    },
    remove: function() {
        document.body.removeChild(this.container);
    },
    progress: function(position) {
        this.position = position;
        var percent = ((this.completed()/this.total()) * 100);
        if (isNaN(percent)) { percent = 0; }
        this.bar.style.width = percent + '%';
    },
    completed: function() {
        var total = 0;
        for (var i = 0, ii = this._completed.length; i < ii; i++) {
            total += this._completed[i][1];
        }
        total += this.position;
        return total;
    },
    total: function() {
        var total = 0;
        for (var i = 0, ii = this.pending.length; i < ii; i++) {
            total += this.pending[i][1];
        }
        if (this.current) {
            total += this.current[1];
        }
        for (i = 0, ii = this._completed.length; i < ii; i++) {
            total += this._completed[i][1];
        }
        return total;
    },
    add: function(script) {
        this.pending.push(script);
        if (!this.current) { this.next(); }
    },
    script_url: function(src) {
        var url = src;
        if (Spontaneous.development) {
            url += '?'+(new Date()).valueOf();
        }
        return url;
    },
    next: function() {
        if (this.pending.length === 0) {
            this.container.className = 'loaded';
            this.remove();
            Spontaneous.onload();
            return;
        }
        var s = this.pending.shift();
        this.current = s;
        if (this.async) {
            var xhr = new XMLHttpRequest();
            xhr.open('GET', this.script_url(s[0]), true);
            var onprogress = (function(req) {
                return function(event) {
                    req.onprogress(event);
                };
            })(this);
            var onreadystatechange = (function(req) {
                return function(event) {
                    req.onreadystatechange(event);
                };
            })(this);
            xhr.onprogress = onprogress;
            xhr.onreadystatechange = onreadystatechange;
            xhr.send();
        } else {
            var body = document.body;
            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.src = this.script_url(this.current[0]);
            var onload = (function(req) {
                return function() {
                    req._completed.push(req.current);
                    req.current = false;
                    req.next();
                };
            })(this);
            script.onload = onload;
            body.appendChild(script);
            // this.current = false;
        }
    },
    onprogress: function(event) {
        this.progress(event.position);
    },
    onreadystatechange: function(event) {
        var xhr = event.currentTarget;
        if (xhr.readyState == 4 && xhr.status === 200) {
            var body = document.body;
            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.text = xhr.responseText;
            body.appendChild(script);
            this._completed.push(this.current);
            this.position = 0;
            this.next();
        }
    }
};
Spontaneous.require = function(script) {
    Spontaneous.Require.add(script);
};