// ==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() {

// shorthand
var _w = unsafeWindow;
var $ = _w.$;
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_to = function(elem, px) {
    if(timer != null) return;

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

        if(--times <= 0) {
            stop_scroll();
            elem._scrollTop = px;
        }
    }, 10);
};
var stop_scroll = function() {
    if(timer != null) {
        clearInterval(timer);
        timer = null;
    }
};

// override scrollTop
var force_nonsmooth = false;
var override_scrollTop = function(elem) {
    elem.__defineGetter__("_scrollTop", elem.__lookupGetter__("scrollTop"));
    elem.__defineSetter__("_scrollTop", elem.__lookupSetter__("scrollTop"));

    elem.__defineGetter__("scrollTop", function() elem._scrollTop);
    elem.__defineSetter__("scrollTop", function(px) {
        stop_scroll();

        var diff = Math.abs(px - elem._scrollTop); 
        if(!force_nonsmooth && (
                config.type == "always" || 
                config.type == "auto" && diff > config.threshold
            ))
            smooth_scroll_to(elem, px);
        else
            elem._scrollTop = px;
    });
};
override_scrollTop(container);

// privent scroll when go to next feed
// override scrollTop of each items for fastladder_fixed_item_height.js
var register_hook = _w.register_hook;
register_hook("BEFORE_PRINTFEED", function() force_nonsmooth = true);
register_hook("BEFORE_SUBS_LOAD", function() force_nonsmooth = true);
register_hook("AFTER_PRINTFEED", function() {
    force_nonsmooth = false;
    Array.slice(container.getElementsByClassName("item")).map(override_scrollTop);    
});
register_hook("AFTER_SUBS_LOAD", function() {
    force_nonsmooth = false;
    Array.slice(container.getElementsByClassName("item")).map(override_scrollTop);    
});

// create additional config
// 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 div = document.createElement("div");
div.innerHTML = <table><tr>
    <th style="background: #ffa">{labels.title}</th>
    <td style="background: #ffa">
        {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}
    </td>
</tr></table>.toString();
var insert = div.getElementsByTagName("tr")[0];

register_hook("AFTER_INIT_CONFIG", function(){
    // add additional config
    var tbody = $("config_detail").getElementsByTagName("tbody")[0];
    tbody.insertBefore(insert.cloneNode(true), tbody.childNodes[8]);

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

    // add submit event
    form.addEventListener("submit", function() {
        for(var i = 0; i < form.smooth_type.length; i++) {
            var radio = form.smooth_type[i];
            if(radio.checked) config.type = radio.value;
        }
        
        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);
});

window.addEventListener('load', function() {
    // Keybind
    var Keybind = _w.Keybind;

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

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

    // scroll to top
    Keybind.add("t", function() container.scrollTop = 0);

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

})();