// ==UserScript==
// @name    搜索增强
// @namespace    
// @version      0.2
// @description    使视障人士更方便的使用百度搜索和网页内搜索，更容易的获取所搜索到的网页的内容，并能快速判断网页的有用程度。
// @author    流水
// @include    http*
// @grant        none
// @downloadURL none
// ==/UserScript==

window.setTimeout(function()
{
	var hotKey = true, nodeIndexForward = 0, dataForSearch = [], resultForKeyword = [], h3FromBaidu = '', intervalForFocus = null, keywordIndex = -1, beSetTabindexArray = [], keywordFromThis = [];
	var lsMessageObject = {origin:'', dataFromBaidu:'', load:false, name:'lsMessage'};
	window.addEventListener('keydown', function(event)
{
	if (!window.event.shiftKey && !window.event.ctrlKey && window.event.altKey && hotKey && window.event.keyCode == 49)
	{
		if (window.location.href.search(/^https:\/\/www\.baidu\.com.+/i) != -1)
		{
			var links = document.getElementsByTagName('a');
			var length = links.length, index = 0;
			if (links[length - 4].innerHTML.indexOf('下一页') != -1)
			{
				var lastH3 = h3FromBaidu;
				links[length - 4].click();
			}
			else {
				alert('未找到下一页链接！');
				return false;
			}
			intervalForFocus = window.setInterval(function()
			{
				++index;
				if (index > 20)
				clearInterval(intervalForFocus);
				var tempH3 = document.querySelector('h3');
				if (!tempH3)
					return false;
				else {
					tempH3 = tempH3.innerHTML;
					if (tempH3 === lastH3)
						return false;
					else {
						document.querySelector('h3 a').focus();
						clearInterval(intervalForFocus);
					}
				}
			}, 500);
		}
		else {
			var keyword = (keywordFromThis.length > 0 ? keywordFromThis : dataForSearch);
			(keywordIndex < keyword.length - 1) ? (++keywordIndex) : (keywordIndex = -1);
			ClearFocus();
		}
	}

	if (window.event.shiftKey && !window.event.ctrlKey && window.event.altKey && hotKey && window.event.keyCode == 49)
	{
		if (window.location.href.search(/^https:\/\/www\.baidu\.com.+/i) != -1)
			return false;
		var keyword = (keywordFromThis.length > 0 ? keywordFromThis : dataForSearch);
		(keywordIndex === -1) ? (keywordIndex = keyword.length - 1) : (--keywordIndex);
		ClearFocus();
	}

	if (!window.event.ctrlKey && !window.event.shiftKey && window.event.altKey && hotKey && window.event.keyCode == 50)
	{
		var noticeString = '', index = 0;
		(keywordFromThis.length === 0) ? (keywordIndex = -1) : (keywordFromThis = []);
		if (dataForSearch.length > 0)
		{
			var htmlText = document.getElementsByTagName('body')[0].innerHTML;
			for (i in dataForSearch)
			{
				if (htmlText.indexOf(dataForSearch[i]) != -1)
				{
					noticeString += dataForSearch[i] + '，';
					keywordFromThis[index] = dataForSearch[i];
					++index;
				}
			}
		}
		GetResultForKeyword();
		if (noticeString.length > 0)
		{
			if (keywordIndex === -1)
			{
				alert('网页出现了关键词' + noticeString);
			}
			noticeString = '';
			for (i in resultForKeyword)
			{
				var start = resultForKeyword[i].index + resultForKeyword[i][0].length;
				var tempResult = resultForKeyword[i][0];
				if (tempResult.indexOf('>') != -1)
				{
					tempResult = tempResult.slice(tempResult.indexOf('>') + 1);
					tempResult += htmlText.slice(start, htmlText.indexOf('<', start));
				}
				else {
					var singleQuote = /(\=\s*\')([^']*)$/;
					var doubleQuote = /(\=\s*\")([^"]*$)/;
					singleQuote = singleQuote.exec(tempResult);
					doubleQuote = doubleQuote.exec(tempResult);
					if (singleQuote && !doubleQuote)
					{
						tempResult = singleQuote[2];
						tempResult += htmlText.slice(start, htmlText.indexOf("\'", start));
					}
					if (!singleQuote && doubleQuote)
					{
						tempResult = doubleQuote[2];
						tempResult += htmlText.slice(start, htmlText.indexOf('\"', start));
					}
					if (!singleQuote && !doubleQuote)
					{
						tempResult = '';
					}
					if (singleQuote && doubleQuote)
					{
						if (singleQuote.index < doubleQuote.index)
						{
							tempResult = doubleQuote[2];
							tempResult += htmlText.slice(start, htmlText.indexOf('\"', start));
						}
						else {
							tempResult = singleQuote[2];
							tempResult += htmlText.slice(start, htmlText.indexOf("\'", start));
						}
					}
				}
				tempResult = tempResult.replace(/&nbsp;/gi, ' ');
				tempResult += '\r\n';
				if (noticeString.indexOf(tempResult) === -1)
					noticeString += tempResult;
			}
			if (keywordIndex === -1)
			{
				(noticeString.length === 0) ? alert('没有搜索到与关键词相关的内容') : alert(noticeString);
			}
			else {
				(noticeString.length === 0) ? alert('没有与' + keywordFromThis[keywordIndex] + '相关的内容') : alert('与' + keywordFromThis[keywordIndex] + '相关的内容为：' + noticeString);
			}
		}
		else {
			(dataForSearch.length > 0) ? alert('没有在网页中搜索到任何关键词') : alert('无法搜索！没有获取到关键词。');
		}
	}

	if (!window.event.shiftKey && !window.event.ctrlKey && window.event.altKey && window.event.keyCode == 48)
	{
		if (hotKey)
		{
			hotKey = false;
			alert('快捷键已禁用！');
		}
		else {
		hotKey = true;
		alert('快捷键已启用！');
		}
	}

	if (!window.event.shiftKey && !window.event.ctrlKey && window.event.altKey && hotKey && window.event.keyCode == 51)
	{
		if (window.location.href.search(/^https:\/\/www\.baidu\.com.+/i) != -1)
		{
			ReviseBaiduTo();
		}
		else {
			if (dataForSearch.length < 1)
			{
				alert('没有获取到关键词，无法进行下一步操作。');
				return false;
			}
			if ((nodeIndexForward === 0) && !document.querySelector('.lsUselessButton0'))
			{
				GetResultForKeyword();
				var htmlText = document.getElementsByTagName('body')[0].innerHTML;
				var myClass = /lsUselessButton-?\d*/;
				var needlessTabindexNode = ['a', 'area', 'label', 'select', 'button', 'textarea'];
				var useParentNode = ['br', 'b', 'i', 'span'];
				var length = resultForKeyword.length, nodeIndex = 0;
				for (i in resultForKeyword)
				{
					var hasSlash = true, beSetTabindex = true, needlessTabindex = false;
					var keyword = resultForKeyword[length - 1 - i][2];
					(keyword.indexOf('/') === -1) ? (hasSlash = false) : (keyword = keyword.replace('/', ''));
					var reg = new RegExp('(<)' + keyword + '(\\s|>|\/\\s*>)', 'gim');
					reg.compile(reg);
					var index = 0, i2 = 0, i3 = 0;
					while ((i2 != -1) && (i3 - 1 < resultForKeyword[length - 1 - i].index))
					{
						if (i3 === 0)
						{
							i2 = htmlText.search(reg);
						}
						if (i3 > 0)
						{
							i2 = htmlText.slice(i3).search(reg);
						}
						if (i2 != -1)
						{
							++index;
						}
						i3 += (i2 + 1);
					}
					var node = (hasSlash) ? (document.getElementsByTagName(keyword)[index - 1].parentNode) : (document.getElementsByTagName(keyword)[index - 1]);
					for (i5 in useParentNode)
					{
						if ( node && (useParentNode[i5] === node.tagName.toLowerCase()))
						{
							if (node.parentNode.tagName.toLowerCase() != 'body')
							{
								node = node.parentNode;
							}
							break;
						}
					}
					if (!node || document.querySelector('.lsUselessButton' + (0 - nodeIndex)) || (node.innerHTML.search(myClass) != -1))
						continue;
					if (node.getAttribute('class'))
					{
						if (node.getAttribute('class').search(myClass) != -1)
							continue;
					}
					for (i4 in needlessTabindexNode)
					{
						if (needlessTabindexNode[i4] === node.tagName.toLowerCase())
						{
							needlessTabindex = true;
							break;
						}
					}
					if (!needlessTabindex)
					{
						(node.getAttribute('tabindex') == null) ? node.setAttribute('tabindex', '-1') : beSetTabindex = false;
					}
					node.classList.add('lsUselessButton' + (0 - nodeIndex));
					beSetTabindexArray[nodeIndex] = beSetTabindex;
					++nodeIndex;
				}
			}
			var nodeObject = document.querySelector('.lsUselessButton' + (nodeIndexForward - (beSetTabindexArray.length - 1)));
			if (nodeObject)
			{
				nodeObject.focus();
				++nodeIndexForward;
			}
			else{
				alert('已到最后一项。');
			} 
		}
	}

	if (window.event.shiftKey && !window.event.ctrlKey && window.event.altKey && hotKey && window.event.keyCode == 51)
	{
		if (dataForSearch.length < 1)
		{
			alert('没有获取到关键词，无法进行下一步操作。');
			return false;
		}
		(nodeIndexForward <= 0) ? alert('已到第一项。') : --nodeIndexForward;
		var nodeObject = document.querySelector('.lsUselessButton' + (nodeIndexForward - (beSetTabindexArray.length - 1)))
		if (nodeObject)
		{
			nodeObject.focus();
		}
	}

	if (!window.event.ctrlKey && !window.event.shiftKey && window.event.altKey && hotKey && window.event.keyCode == 52)
	{
		ClearFocus();
		keywordIndex = -1;
		var data = prompt('请输入要搜索的关键词，中间用空格或竖杠分开');
		(data != null && data != '') ? SetDataForSearch(data) : this.alert('没有获取到正确的输入');
	}
})

window.addEventListener('load', function()
{
	lsMessageObject.origin = self.location.protocol + '\/\/' + self.location.hostname;
	lsMessageObject.load = true;
	if (window.opener)
	{
		window.opener.postMessage(lsMessageObject, '*');
	}
	RemoveIframes();
})

window.addEventListener('message', function(event)
	{
		if (event.data.name === 'lsMessage')
		{
			if (event.data.dataFromBaidu && !lsMessageObject.dataFromBaidu)
			{
			lsMessageObject.dataFromBaidu = event.data.dataFromBaidu;
			SetDataForSearch();
			}
			if (!event.data.dataFromBaidu && lsMessageObject.dataFromBaidu)
			{
				event.source.postMessage(lsMessageObject, '*');
			}
		}
	})

	function ReviseBaiduTo()
	{
		if (window.location.href.search(/^https:\/\/www\.baidu\.com.+/i) == -1)
			return false;
		var title = document.querySelector('head title').text;
		if (lsMessageObject.dataFromBaidu != title)
		{
			lsMessageObject.dataFromBaidu = title;
		}
		var linksForBaidu = document.querySelectorAll('h3 a');
		for (var i = 0; i < linksForBaidu.length; ++i)
		{
			linksForBaidu[i].onclick = function()
			{
				var windowFromBaidu = window.open(this.getAttribute('href'));
				setTimeout(function()
				{
					windowFromBaidu.postMessage(lsMessageObject, '*');
				}, 3000);
				return false;
			}
		}
		linksForBaidu = null;
	}

	function GetResultForKeyword()
	{
		if (!dataForSearch)
			return false;
		var needlessNode = ['input', 'script'];
		var htmlText = document.getElementsByTagName('body')[0].innerHTML;
		resultForKeyword = [];
		var index = 0, keyword = [];
		if (keywordIndex === -1)
		{
			keyword = (keywordFromThis.length > 0 ? keywordFromThis : dataForSearch);
		}
		else {
			keyword[0] = (keywordFromThis.length > 0 ? keywordFromThis[keywordIndex] : dataForSearch[keywordIndex]);
		}
		for (i in keyword)
		{
			var reg = new RegExp('(<)(\/?\\w+)(\\s|>|\/\\s*>)([^<]*)(?=' + keyword[i] + ')', 'gim');
			reg.compile(reg);
			var tempResult = reg.exec(htmlText);
			while (tempResult != null)
			{
				var repeated = false, isNeedlessNode = false;
				for (i2 in needlessNode)
				{
					if (tempResult[2].toLowerCase().indexOf(needlessNode[i2]) != -1)
					{
						isNeedlessNode = true;
						break;
					}
				}
				for (i2 in resultForKeyword)
				{
					if (tempResult.index === resultForKeyword[i2].index)
					{
						repeated = true;
						break;
					}
				}
				if (!repeated && !isNeedlessNode)
				{
					resultForKeyword[index] = tempResult;
					++index;
				}
				tempResult = reg.exec(htmlText);
			}
			reg = null;
		}
		resultForKeyword.sort(function(a, b)
		{
			return a.index - b.index;
		});
	}

function RemoveIframes()
{
	var urlArray = [/https:\/\/pos\.baidu\.com/i, /https:\/\/g\.fastapi\.net/i];
	var needLessFrames = [], index = 0;
	for (i in urlArray)
	{
		var framesObject = document.getElementsByTagName('iframe');
		for (var i2 = 0; i2 < framesObject.length; ++i2)
		{
			if (!framesObject[i2])
				continue;
			var src = framesObject[i2].getAttribute('src');
			if (src && (src.search(urlArray[i]) != -1))
			{
				needLessFrames[index] = framesObject[i2];
				++index;
			}
		}
	}
	for (i in needLessFrames)
	{
		needLessFrames[i].parentNode.removeChild(needLessFrames[i]);
	}
}

function ClearFocus()
{
	for (i in beSetTabindexArray)
	{
		var node = document.querySelector('.lsUselessButton' + (i - (beSetTabindexArray.length - 1)));
		if (node.getAttribute('tabindex') && beSetTabindexArray[beSetTabindexArray.length - 1 - i])
		{
			node.removeAttribute('tabindex');
		}
		node.classList.remove('lsUselessButton' + (i - (beSetTabindexArray.length - 1)));
	}
	nodeIndexForward = 0;
	beSetTabindexArray = [];
}

function SetDataForSearch(data)
{
	dataForSearch = [];
	if (!lsMessageObject.dataFromBaidu && !arguments[0])
		return false;
	var cut_off = [' ', '|'];
	var end = lsMessageObject.dataFromBaidu.indexOf('_百度搜索');
	data = (arguments[0] ? arguments[0] : lsMessageObject.dataFromBaidu.slice(0, end));
	for (i in cut_off)
	{
		if (data.indexOf(cut_off[i]) != -1)
		{
			cut_off = cut_off[i];
			break;
		}
		if (i === cut_off.length - 1)
		{
			cut_off = null;
		}
	}
	if (!cut_off)
	{
		dataForSearch[0] = data;
	}
	else {
		var reg = new RegExp('([^' + cut_off + ']+)', 'gim');
		var needSpace = /[a-zA-Z\d]/;
		var keyword = [], index = 0, keywordCount = 0, tempResult = '';
		tempResult = reg.exec(data);
		while (tempResult)
		{
			keyword[index] = tempResult[1];
			++index;
			tempResult = reg.exec(data);
		}
		keywordCount = index;
		for (var i = 0; i < keywordCount; ++i)
		{
			dataForSearch[i] = keyword[i];
		}
		if (keywordCount > 1)
		{
			for (var i =0; i < keywordCount - 1; ++i)
			{
				for (var i2 = i + 1; i2 < keywordCount; ++i2)
				{
					dataForSearch[index] = (needSpace.test(keyword[i].slice(keyword[i].length - 1, keyword[i].length)) && needSpace.test(keyword[i2].slice(0, 1))) ? (keyword[i] + ' ' + keyword[i2]) : (keyword[i] + keyword[i2]);
					++index;
					dataForSearch[index] = (needSpace.test(keyword[i2].slice(keyword[i2].length - 1, keyword[i2].length)) && needSpace.test(keyword[i].slice(0, 1))) ? (keyword[i2] + ' ' + keyword[i]) : (keyword[i2] + keyword[i]);
					++index;
				}
			}
		}
		if (keywordCount > 2)
		{
			for (var i = 0; i < keywordCount; ++i)
			{
				if (i ===0)
				{
					dataForSearch[index] = '';
				}
				var length = dataForSearch[index].length;
				((length > 0) && needSpace.test(dataForSearch[index].slice(length - 1, length)) && needSpace.test(keyword[i].slice(0, 1))) ? (dataForSearch[index] += ' ' + keyword[i]) : (dataForSearch[index] += keyword[i]);
			}
		}
	}
	PlaySound();
}

function PlaySound()
{
	var audioContext = new AudioContext();
	var oscillator = audioContext.createOscillator();
	var gainNode = audioContext.createGain();
	oscillator.connect(gainNode);
	gainNode.connect(audioContext.destination);
	oscillator.type = 'sine';
	oscillator.frequency.value = 400.00;
	gainNode.gain.setValueAtTime(0, audioContext.currentTime);
	gainNode.gain.linearRampToValueAtTime(1, audioContext.currentTime + 0.01);
	oscillator.start(audioContext.currentTime);
	gainNode.gain.exponentialRampToValueAtTime(0.001, audioContext.currentTime + 1);
	oscillator.stop(audioContext.currentTime + 1);
}

window.setTimeout(function()
{
	if (window.location.href.search(/^https:\/\/www\.baidu\.com.+/i) != -1)
	{
		window.setInterval(function()
		{
			var tempH3 = document.querySelector('h3');
			if (!tempH3)
			{
				h3FromBaidu = '';
				return false;
			}
			else {
				var text = tempH3.innerHTML;
				if (text == h3FromBaidu)
					return false;
				else {
					h3FromBaidu = text;
					ReviseBaiduTo();
				}
			}
		}, 1000);
	}
}, 3000)

}, 0)