// Written by Dave Child
// http://www.addedbytes.com
// http://code.google.com/p/addedbytes-userscripts/
//
// ==UserScript==
// @name          Auto Save Forms
// @description   Saves form data every few seconds and gives option of repopulating form later.
// ==/UserScript==



(function() {

    var d = document;
    var i = d.getElementsByTagName('input'); // inputs
    var t = d.getElementsByTagName('textarea'); // textareas
    var f = d.getElementsByTagName('form'); // textareas

    // Strip i down to just text inputs
    var newi = new Array();
    for (j=0;j<i.length;j++) {
        if (i[j].type == 'text') {
            newi.push(i[j]);
        }
    }
    i = newi;

    var box; // Box for offer to repopulate
    var boxtext; // Text for offer to repopulate
    var j;
    var e = new Array();
    var eo;
    var saving;

    function start() {
        for (j = 0; j < f.length; j++) {
            f[j].addEventListener("submit", clear, false);
        }
        for (j = 0; j < i.length; j++) {
            i[j].addEventListener("keyup", prepsave, false);
        }
        for (j = 0; j < t.length; j++) {
            t[j].addEventListener("keyup", prepsave, false);
        }
        offer_repopulate();
    }

    function clear() {
        var today = new Date();
        var expiry = new Date(today.getTime() - 30 * 24 * 60 * 60 * 1000); // In the past to expire cookie
        d.cookie = "FormsSavedData=; expires=" + expiry.toGMTString() + "; path=/";
    }

    function getCookie(name) {
        var re = new RegExp(name + "=([^;]+)");
        var value = re.exec(d.cookie);
        return (value != null) ? unescape(value[1]) : false;
    }

    function setCookie(name, value) {
        var today = new Date();
        var expiry = new Date(today.getTime() + 30 * 24 * 60 * 60 * 1000); // Expires after a month

        d.cookie = name + "=" + escape(value) + "; expires=" + expiry.toGMTString() + "; path=/";
    }

    function prepsave() {
        clearInterval(saving);
        saving = setInterval(savedata, 500);
    }

    function savedata() {
        e = new Array();
        for (j=0;j<i.length;j++) {
            e.push(i[j].value.toString());
        }
        for (j=0;j<t.length;j++) {
            e.push(t[j].value.toString());
        }
        setCookie('FormsSavedData', e.join("|"));
        clearInterval(saving);
    }

    function repopulate() {
        eo = getCookie('FormsSavedData').split("|");
        for (j=0;j<i.length;j++) {
            i[j].value = eo.shift();
        }
        for (j = 0; j < t.length; j++) {
            t[j].value = eo.shift();
        }
    }

    function offer_repopulate() {
        if (getCookie('FormsSavedData')) {
            // Cookie found. Write offer to repopulate to page.
            box = d.createElement("div");
            box.setAttribute("style", 
                               "cursor: pointer; " +
                               "position: absolute; " +
                               "top: 20px; " +
                               "right: 20px; " +
                               "background-color: #fee; " +
                               "color: #f00; " +
                               "border: 1px dotted #f00; " +
                               "padding: 3px 8px;");
            d.body.appendChild(box);
            box.addEventListener("click", repopulate, false);

            boxtext = d.createTextNode('Repopulate Form');
            box.appendChild(boxtext);
        }
    }
    
    window.addEventListener("load", start, false);

})();