// ==UserScript==
// @name               My Mouse Gestures
// @name:zh-CN         我的鼠标手势
// @name:zh-TW         我的滑鼠手勢
// @description        A simple mouse gesture script
// @description:zh-CN  一个简单的鼠标手势脚本
// @description:zh-TW  一個簡單的滑鼠手勢腳本
// @version            0.1.6
// @include            *
// @run-at             document-start
// @grant              GM_openInTab
// @grant              window.close
// @namespace          https://greasyfork.org/users/4968
// @downloadURL none
// ==/UserScript==

// --- Settings ---

const SENSITIVITY = 3; // 1 ~ 5
const TOLERANCE = 3; // 1 ~ 5

const funcs = {
    'DR': function() {
        window.top.close();
    },
    'U': function() {
        window.scrollTo(0, 0);
    },
    'D': function() {
        window.scrollTo(0, 1073741824);
    },
    'L': function() {
        window.history.back();
    },
    'R': function() {
        window.history.forward();
    },
    'RU': function() {
        GM_openInTab('about:newtab', false);
    },
    'UD': function() {
        window.location.reload();
    }
};

// ----------------

const s = 1 << ((7 - SENSITIVITY) << 1);
const t1 = Math.tan(0.15708 * TOLERANCE),
      t2 = 1 / t1;

let x, y, path;

const tracer = function(e) {
    let cx = e.clientX,
        cy = e.clientY,
        deltaX = cx - x,
        deltaY = cy - y,
        slope = Math.abs(deltaY / deltaX),
        distance = deltaX * deltaX + deltaY * deltaY,
        direction = '';
    if (distance > s) {
        if (slope > t1) {
            if (deltaY > 0) {
                direction = 'D';
            } else {
                direction = 'U';
            }
        } else if (slope <= t2) {
            if (deltaX > 0) {
                direction = 'R';
            } else {
                direction = 'L';
            }
        }
        if (path.charAt(path.length - 1) !== direction) {
            path += direction;
        }
        x = cx;
        y = cy;
    }
};

window.addEventListener('mousedown', function(e) {
    if (e.which === 3) {
        x = e.clientX;
        y = e.clientY;
        path = "";
        window.addEventListener('mousemove', tracer, false);
    }
}, false);

window.addEventListener('contextmenu', function(e) {
    window.removeEventListener('mousemove', tracer, false);
    if (path !== "") {
        e.preventDefault();
        if (funcs.hasOwnProperty(path)) {
            funcs[path]();
        }
    }
}, false);