using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace Sog.Service
{
    //脏词过滤， AC自动机算法
    public class AcNode
    {
        public char m_data;
        public Dictionary<char, AcNode> m_children = new Dictionary<char, AcNode>();
        public bool m_isEndChar = false; //结尾字符为true
        public int m_length = -1; // isEndChar=true时，记录模式串长度
        public AcNode m_fail = null; //失败指针

        public AcNode(char data)
        {
            m_data = data;
        }

        public void  Clear()
        {
            foreach(var it in m_children)
            {
                it.Value.Clear();
            }
            m_children.Clear();
        }
    }
    public class DirtyServiceAc : Singleton<DirtyServiceAc>
    {
        private AcNode m_root;

       

        public void InitFromFile(string filename)
        {
            if (!File.Exists(filename))
            {
                TraceLog.Error("DirtyServiceAc.InitFromFile file {0} not exists", filename);
                return;
            }

            //这样支持reload
            if(m_root == null)
            {
                m_root = new AcNode('/');
            }
           
            m_root.Clear();

            string[] allline = File.ReadAllLines(filename);

            foreach (var line in allline)
            {
                if (string.IsNullOrEmpty(line))
                {
                    continue;
                }

                if (string.IsNullOrWhiteSpace(line))
                {
                    continue;
                }

                //if (line.Length < 2)
                //{
                //    continue;
                //}

                string lowLine = line.ToLower();

                //转成小写
                Insert(lowLine);
            }

            BuildFailurePointer();
            //BFS();
        }
        private void Insert(string text)
        {
            var p = m_root;
            foreach(char c in text)
            {
                if (!p.m_children.ContainsKey(c)) //不存在新建
                {
                    AcNode newNode = new AcNode(c);
                    p.m_children.Add(c, newNode);
                }

                p = p.m_children[c];
            }

            if(p.m_isEndChar) //存在重复插入
            {
                TraceLog.Trace("DirtyServiceAc.Insert {0} is exist", text);
                return;
            }

            p.m_isEndChar = true;
            p.m_length = text.Length;

        }

        private void BuildFailurePointer()
        {
            Queue<AcNode> queue = new Queue<AcNode>();
            m_root.m_fail = null;
            queue.Enqueue(m_root);
            while(queue.Count > 0)
            {
                AcNode p = queue.Dequeue();
                foreach(var pc in p.m_children)
                {
                    if(p == m_root)
                    {
                        pc.Value.m_fail = m_root;
                    }
                    else
                    {
                        AcNode q = p.m_fail;
                        while(q != null)
                        {
                            if(q.m_children.ContainsKey(pc.Value.m_data))
                            {
                                pc.Value.m_fail = q.m_children[pc.Value.m_data];
                                break;
                            }
                            q = q.m_fail;
                        }

                        if(q == null)
                        {
                            pc.Value.m_fail = m_root;
                        }
                    }
                    queue.Enqueue(pc.Value);
                }
            }
        }

        //private void  BFS()
        //{
        //    Queue<AcNode> queue = new Queue<AcNode>();
        //    queue.Enqueue(m_root);
        //    while(queue.Count > 0)
        //    {
        //        var q = queue.Dequeue();
        //        if(q != m_root && q.m_fail == null)
        //        {
        //            TraceLog.Error("DirtyServiceAc.BFS fail is nill data {0}", q.m_data);         
        //        }
        //        foreach (var qc in q.m_children)
        //        {
        //            queue.Enqueue(qc.Value);
        //        }
        //    }
        //}

        //匹配脏词，匹配成功放回true，匹配失败返回false
        private bool Match(string text, ref List<KeyValuePair<int, int>> result, bool bOnlyCheck = false)
        {
            result.Clear();
            AcNode p = m_root;
            for(int i = 0; i < text.Length; i++)
            {
                while(!p.m_children.ContainsKey(text[i]) && p!= m_root)
                {
                    p = p.m_fail;
                }

                if(p.m_children.ContainsKey(text[i]))
                {
                    p = p.m_children[text[i]];
                }
                else
                {
                    p = m_root;
                }

                AcNode tmp = p;
                while(tmp != m_root && tmp != null)
                {
                    if(tmp.m_isEndChar)
                    {
                        int pos = i - tmp.m_length + 1;
                        result.Add(new KeyValuePair<int, int>(pos, tmp.m_length));
                        if(bOnlyCheck) //只做校验，不用全匹配，立即返回
                        {
                            return true;
                        }
                    }
                    if(tmp.m_fail == null)
                    {
                        TraceLog.Error("DirtyServiceAc Match  is null data {0}", tmp.m_data);
                    }
                    tmp = tmp.m_fail;
                }
               

            }

            return result.Count > 0;
        }

        //替换脏词，如果存在替换返回true， 不存在返回false
        public bool ReplaceDirtyText(string content, out string outcontent)
        {
            outcontent = content;

            string lowContent = content.ToLower();
            char[] charArray = null;

            List<KeyValuePair<int, int>> result = new List<KeyValuePair<int, int>>();
            bool bMatch = Match(lowContent, ref result);
            if(bMatch && result.Count > 0)
            {
                charArray = content.ToArray();
                foreach (var it in result)
                {
                    for(int i = it.Key; i < it.Key + it.Value; i++)
                    {

                        charArray[i] = '*';
                    }
                }
               
            }
            else
            {
                return false;
            }

            StringBuilder builder = new StringBuilder(charArray.Length);
            builder.Append(charArray);

            outcontent = builder.ToString();

            return true;

        }

        //只做校验,没有脏词返回true, 有脏词false
        public bool CheckDirty(string content)
        {  
            string lowContent = content.ToLower();
            List<KeyValuePair<int, int>> result = new List<KeyValuePair<int, int>>();
            return !Match(lowContent, ref result, true);
        }

    }
}