using System;
using System.Collections.Generic;
using System.Text;
using log4net;
using System.Threading;
using DTcms.Common;
using Lucene.Net.Store;
using System.IO;
using Lucene.Net.Index;
using Lucene.Net.Analysis.PanGu;
using Lucene.Net.Documents;
using Lucene.Net.Search;
using Lucene.Net.QueryParsers;
using PanGu;
using PanGu.HighLight;

namespace DTcms.Web.UI
{
public class SearchHelper
{
private static ILog logger = LogManager.GetLogger(typeof(SearchHelper));

#region 创建单例
// 定义一个静态变量来保存类的实例
private static SearchHelper uniqueInstance;

// 定义一个标识确保线程同步
private static readonly object locker = new object();

// 定义私有构造函数，使外界不能创建该类实例
private SearchHelper()
{ }

/// <summary>
/// 定义公有方法提供一个全局访问点,同时你也可以定义公有属性来提供全局访问点
/// </summary>
/// <returns></returns>
public static SearchHelper GetInstance()
{
// 当第一个线程运行到这里时，此时会对locker对象 "加锁"，
// 当第二个线程运行该方法时，首先检测到locker对象为"加锁"状态，该线程就会挂起等待第一个线程解锁
// lock语句运行完之后（即线程运行完之后）会对该对象"解锁"
lock (locker)
{
// 如果类的实例不存在则创建，否则直接返回
if (uniqueInstance == null)
{
uniqueInstance = new SearchHelper();
}
}

return uniqueInstance;
}
#endregion

private Queue<IndexJob> jobs = new Queue<IndexJob>(); //任务队列,保存生产出来的任务和消费者使用,不使用list避免移除时数据混乱问题

/// <summary>
/// 任务类,包括任务的Id ,操作的类型
/// </summary>
class IndexJob
{
public int Id { get; set; }
public JobType JobType { get; set; }
}
/// <summary>
/// 枚举,操作类型是增加还是删除
/// </summary>
enum JobType { Add, Remove }

#region 任务索引
/// <summary>
/// 启动消费者线程
/// </summary>
public void CustomerStart()
{

log4net.Config.XmlConfigurator.Configure();

PanGu.Segment.Init(PanGuPath);

Thread threadIndex = new Thread(IndexOn);
threadIndex.IsBackground = true;
threadIndex.Start();
}

/// <summary>
/// 索引任务线程
/// </summary>
private void IndexOn()
{
logger.Debug("索引任务线程启动");
while (true)
{
if (jobs.Count <= 0)
{
Thread.Sleep(5 * 1000);
continue;
}
//创建索引目录
if (!System.IO.Directory.Exists(IndexDic))
{
System.IO.Directory.CreateDirectory(IndexDic);
}
FSDirectory directory = FSDirectory.Open(new DirectoryInfo(IndexDic), new NativeFSLockFactory());
bool isUpdate = IndexReader.IndexExists(directory);
logger.Debug("索引库存在状态" + isUpdate);
if (isUpdate)
{
//如果索引目录被锁定（比如索引过程中程序异常退出），则首先解锁
if (IndexWriter.IsLocked(directory))
{
logger.Debug("开始解锁索引库");
IndexWriter.Unlock(directory);
logger.Debug("解锁索引库完成");
}
}
IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED);
ProcessJobs(writer);
writer.Close();
directory.Close();//不要忘了Close，否则索引结果搜不到
logger.Debug("全部索引完毕");
}
}
private void ProcessJobs(IndexWriter writer)
{
while (jobs.Count != 0)
{
IndexJob job = jobs.Dequeue();
writer.DeleteDocuments(new Term("number", job.Id.ToString()));
//如果“添加文章”任务再添加，
if (job.JobType == JobType.Add)
{
BLL.article bll = new BLL.article();
if (bll == null)//有可能刚添加就被删除了
{
continue;
}
Model.article art = bll.GetArticleModel(job.Id);

string channel_id = art.channel_id.ToString();
string title = art.title;
DateTime time = art.add_time;
string content = Utils.DropHTML(art.content.ToString());
string Addtime = art.add_time.ToString("yyyy-MM-dd");

Document document = new Document();
//只有对需要全文检索的字段才ANALYZED
document.Add(new Field("number", job.Id.ToString(), Field.Store.YES, Field.Index.NOT_ANALYZED));
document.Add(new Field("title", title, Field.Store.YES, Field.Index.ANALYZED, Lucene.Net.Documents.Field.TermVector.WITH_POSITIONS_OFFSETS));
document.Add(new Field("channel_id", channel_id, Field.Store.YES, Field.Index.NOT_ANALYZED));
document.Add(new Field("Addtime", Addtime, Field.Store.YES, Field.Index.NOT_ANALYZED));
document.Add(new Field("content", content, Field.Store.YES, Field.Index.ANALYZED, Lucene.Net.Documents.Field.TermVector.WITH_POSITIONS_OFFSETS));
writer.AddDocument(document);
logger.Debug("索引" + job.Id + "完毕");
}
}
}
#endregion

#region 任务添加
public void AddArticle(int artId)
{
IndexJob job = new IndexJob();
job.Id = artId;
job.JobType = JobType.Add;
logger.Debug(artId + "加入任务列表");
jobs.Enqueue(job);//把任务加入商品库
}

public void RemoveArticle(int artId)
{
IndexJob job = new IndexJob();
job.JobType = JobType.Remove;
job.Id = artId;
logger.Debug(artId + "加入删除任务列表");
jobs.Enqueue(job);//把任务加入商品库
}
#endregion

#region 从索引搜索结果
/// <summary>
/// 从索引搜索结果
/// </summary>
public List<Model.article> SearchIndex(string Words, int PageSize, int PageIndex, out int _totalcount)
{
_totalcount = 0;
Dictionary<string, string> dic = new Dictionary<string, string>();
BooleanQuery bQuery = new BooleanQuery();
string title = string.Empty;
string content = string.Empty;
title = GetKeyWordsSplitBySpace(Words);
QueryParser parse = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "title", new PanGuAnalyzer());
Query query = parse.Parse(title);
parse.SetDefaultOperator(QueryParser.Operator.AND);
bQuery.Add(query, BooleanClause.Occur.SHOULD);
dic.Add("title", Words);

content = GetKeyWordsSplitBySpace(Words);
QueryParser parseC = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "content", new PanGuAnalyzer());
Query queryC = parseC.Parse(content);
parseC.SetDefaultOperator(QueryParser.Operator.AND);
bQuery.Add(queryC, BooleanClause.Occur.SHOULD);
dic.Add("content", Words);
if (bQuery != null && bQuery.GetClauses().Length > 0)
{
return GetSearchResult(bQuery, dic, PageSize, PageIndex, out _totalcount);
}
return null;
}
/// <summary>
/// 获取
/// </summary>
/// <param name="bQuery"></param>
private List<Model.article> GetSearchResult(BooleanQuery bQuery, Dictionary<string, string> dicKeywords, int PageSize, int PageIndex, out int totalCount)
{
List<Model.article> list = new List<Model.article>();
FSDirectory directory = FSDirectory.Open(new DirectoryInfo(IndexDic), new NoLockFactory());
IndexReader reader = IndexReader.Open(directory, true);
IndexSearcher searcher = new IndexSearcher(reader);
TopScoreDocCollector collector = TopScoreDocCollector.create(1000, true);
Sort sort = new Sort(new SortField("Addtime", SortField.DOC, true));
searcher.Search(bQuery, null, collector);
totalCount = collector.GetTotalHits();//返回总条数
TopDocs docs = searcher.Search(bQuery, (Filter)null, PageSize * PageIndex, sort);
if (docs != null && docs.totalHits > 0)
{
for (int i = 0; i < docs.totalHits; i++)
{
if (i >= (PageIndex - 1) * PageSize && i < PageIndex * PageSize)
{
Document doc = searcher.Doc(docs.scoreDocs[i].doc);
Model.article model = new Model.article()
{
id = int.Parse(doc.Get("number").ToString()),
title = doc.Get("title").ToString(),
content = doc.Get("content").ToString(),
add_time = DateTime.Parse(doc.Get("Addtime").ToString()),
channel_id = int.Parse(doc.Get("channel_id").ToString())
};
list.Add(SetHighlighter(dicKeywords, model));
}
}
}
return list;
}
/// <summary>
/// 设置关键字高亮
/// </summary>
/// <param name="dicKeywords">关键字列表</param>
/// <param name="model">返回的数据模型</param>
/// <returns></returns>
private Model.article SetHighlighter(Dictionary<string, string> dicKeywords, Model.article model)
{
SimpleHTMLFormatter simpleHTMLFormatter = new PanGu.HighLight.SimpleHTMLFormatter("<font color=\"red\">", "</font>");
Highlighter highlighter = new PanGu.HighLight.Highlighter(simpleHTMLFormatter, new Segment());
highlighter.FragmentSize = 250;
string strTitle = string.Empty;
string strContent = string.Empty;
dicKeywords.TryGetValue("title", out strTitle);
dicKeywords.TryGetValue("content", out strContent);
if (!string.IsNullOrEmpty(strTitle))
{
string title = model.title;
model.title = highlighter.GetBestFragment(strTitle, model.title);
if (string.IsNullOrEmpty(model.title))
{
model.title = title;
}
}
if (!string.IsNullOrEmpty(strContent))
{
string content = model.content;
model.content = highlighter.GetBestFragment(strContent, model.content);
if (string.IsNullOrEmpty(model.content))
{
model.content = content;
}
}
return model;
}
/// <summary>
/// 处理关键字为索引格式
/// </summary>
/// <param name="keywords"></param>
/// <returns></returns>
private string GetKeyWordsSplitBySpace(string keywords)
{
PanGuTokenizer ktTokenizer = new PanGuTokenizer();
StringBuilder result = new StringBuilder();
ICollection<WordInfo> words = ktTokenizer.SegmentToWordInfos(keywords);
foreach (WordInfo word in words)
{
if (word == null)
{
continue;
}
result.AppendFormat("{0}^{1}.0 ", word.Word, (int)Math.Pow(3, word.Rank));
}
return result.ToString().Trim();
}
#endregion

/// <summary>
/// 索引存放目录
/// </summary>
protected string IndexDic
{
get
{
return Utils.GetXmlMapPath(DTKeys.FILE_INDEXDICPATH_XML_CONFING);
}
}
/// <summary>
/// 盘古分词配置目录
/// </summary>
protected string PanGuPath
{
get
{
return Utils.GetXmlMapPath(DTKeys.FILE_PANGU_XML_CONFING);
}
}
}
}

SearchHelper