// ==UserScript==
// @name           ldr smooth scroll
// @namespace      http://relaxedcolumn.blog8.fc2.com/
// @description    smoothing scroll for livedoor reader (ldr) and fastladder
// @include        http://reader.livedoor.com/reader/
// @include        http://fastladder.com/reader/
// ==/UserScript==
//

(function() {
    var w = unsafeWindow;

    w.addEventListener('load', function() {
        // shorthand
        var shorthands = "document $ Control Form Keybind register_hook message".split(" ");
        for(var i = 0, len = shorthands.length; i < len; ++i) {
            eval("var " + shorthands[i] + " = w." + shorthands[i]);
        }
        var container = $("right_container");

        // config
        var config = {
            type: "always",
            velocity: 30,
            threshold: 250
        };

        // load config
        for(var val in config) {
            config[val] = GM_getValue(val, config[val]);
        }

        // smooth scroll
        var timer = null;
        var smooth_scroll_by = function(px) {
            if(timer != null) return;

            var step = (px < 0 ? -1 : 1) * config.velocity
            var times = Math.floor(px / step);
            var remain = px - step * times;
            timer = setInterval(function() {
                container._scrollTop += step;

                if(--times <= 0) {
                    stop_scroll();
                    container._scrollTop += remain;
                }
            }, 10);
        };

        var stop_scroll = function() {
            if(timer != null) {
                clearInterval(timer);
                timer = null;
            }
        };

        var should_smooth = function(px) {
            return config.type == "always"
                || config.type == "auto" && Math.abs(px) > config.threshold;
        };

        register_hook("before_printfeed", stop_scroll);

        // override scrollTop
        container.__defineGetter__("_scrollTop", container.__lookupGetter__("scrollTop"));
        container.__defineSetter__("_scrollTop", container.__lookupSetter__("scrollTop"));

        container.__defineGetter__("scrollTop", function() container._scrollTop);
        container.__defineSetter__("scrollTop", function(px) {
            var diff = px - container._scrollTop; 
            
            if(should_smooth(diff))
                smooth_scroll_by(diff);
            else
                container._scrollTop = px;
        });

        // add config
        register_hook("after_init_config", function(){
            // get DOM nodes
            var form = $("config_form");
            var config_detail = $("config_detail");
            var tbody = config_detail.getElementsByTagName("tbody")[0];
            var insert_target = tbody.childNodes[8];

            // localization
            var labels = {};
            // fastladder
            if(location.href.match(/^http:\/\/fastladder/)) {
                labels.title = "Smoothing scroll";
                labels.description = "Smooth scroll mode and settings";
                labels.none = "none";
                labels.always = "always";
                labels.auto = "auto (smoothing only when scroll length is longer than threshold)";
                labels.velocity = "velocity";
                labels.velocity_description = "px (more than 1)";
                labels.threshold = "threshold";
                labels.threshold_description = "px (only for auto)";
            }
            // livedoor reader
            else {
                labels.title = "スムーズスクロール";
                labels.description = "スムーズのタイプと動作の設定ができます";
                labels.none = "なし";
                labels.always = "常に";
                labels.auto = "自動（スクロール距離が閾値より長いときだけスムージング）";
                labels.velocity = "速さ";
                labels.velocity_description = "px （1以上）";
                labels.threshold = "閾値";
                labels.threshold_description = "px （自動のときのみ）";
            }

            // create config nodes
            var smooth_tr = document.createElement("tr");

            var smooth_th = document.createElement("th");
            smooth_th.textContent = labels.title;
            smooth_th.style.background = "#ffa";
            smooth_tr.appendChild(smooth_th);

            var smooth_td = document.createElement("td");
            smooth_td.style.background = "#ffa";
            smooth_td.innerHTML = <>
                {labels.description}<br />
                <input name="smooth_type" value="none" type="radio" />{labels.none}<br />
                <input name="smooth_type" value="always" type="radio" />{labels.always}<br />
                <input name="smooth_type" value="auto" type="radio" />{labels.auto}<br />
                {labels.velocity}
                <input name="smooth_velocity" value="1" size="6" type="text" />
                {labels.velocity_description}<br />
                {labels.threshold}
                <input name="smooth_threshold" value="100" size="6" type="text" />
                {labels.threshold_description}
            </>.toString();
            smooth_tr.appendChild(smooth_td);

            tbody.insertBefore(smooth_tr, insert_target);

            // fill value
            var fillConfig = {};
            for(var val in config) {
                fillConfig["smooth_" + val] = config[val];
            }
            Form.fill(form, fillConfig);

            // add submit event
            form.addEventListener("submit", function() {
                for(var i = 0, len = form.smooth_type.length; i < len; ++i) {
                    var radio = form.smooth_type[i];
                    if(radio.checked) {
                        config.type = radio.value;
                        break;
                    }
                }
                
                var v = parseInt(form.smooth_velocity.value);
                config.velocity = (v > 0) ? v : 30;
                config.threshold = parseInt(form.smooth_threshold.value);

                for(var val in config) {
                    GM_setValue(val, config[val]);
                }
            }, false);
        });

        // Keybind
        // toggle smooth type
        var next_type = {
            none:   "always",
            always: "auto",
            auto:   "none"
        };
        Keybind.add("S", function() {
            config.type = next_type[config.type];  
            message('set smooth: "' + config.type + '"');

            window.setTimeout(function() {
                GM_setValue("type", config.type);
            }, 0);
        });

        // scroll to top
        Keybind.add("t", Control.scroll_to_zero);

        // scroll to bottom
        Keybind.add("b", function() {
            var divs = container.getElementsByTagName("h2");
            var last_item = divs[divs.length - 1].parentNode.parentNode;
            var target = last_item.offsetTop + last_item.offsetHeight
                - container.offsetHeight + 40;
            container.scrollTop = target;
        });
    }, false);
})();