using System;
using System.Collections.Generic;
using System.Text;

namespace VEPROMS.CSLA.Library
{
	public partial class ROFST
	{
		private string _ROValue = "";
		private List<string> lstRoValues;
		private Dictionary<string,string> DictROVar = new Dictionary<string,string>();

		public List<string> GetROReturnValue(string roval /*, DocVersionInfo docverinfo */)
		{
			lstRoValues = new List<string>();
			DictROVar = new Dictionary<string,string>(); // set up a diction of RO defined Variables
			string tmp = ProcessRO(docVerInfo.ProcessDocVersionSpecificInfo(roval), false /*, docverinfo */);
			if (lstRoValues.Count == 0) // was not a multiple return value
				lstRoValues.Add(tmp);
			return lstRoValues;
		}

		private string ProcessRO(string roval, bool multiRtnVal /*, DocVersionInfo docverinfo*/)
		{
			string str = roval;
			string rtnstr = "";
			int l = roval.Length;
			while (l > 0)
			{
				int ptr = NextDelimiter("{", str);
				if (ptr == -1)
				{ // add remaining text
					//add(new seText(str, l));
					rtnstr += str;
					l = 0; // break out of while loop
				}
				else
				{
					int cnt = ptr; //(int)(ptr - str);
					if (cnt > 0)
					{	// add text
						//add(new seText(str, cnt));
						rtnstr += str.Substring(0, cnt);
						l -= cnt;
						//str = ptr;
						str = str.Substring(ptr);
					}
					ptr = MatchingBrace(str) + 1;
					cnt = ptr; //(int)(ptr - str);
					bool nfnd = false;
					string pbstr = ProcessBrace(str.Substring(1, cnt - 2), cnt - 2, ref nfnd, multiRtnVal /*, docverinfo */);
					if (nfnd)
						rtnstr += str.Substring(0, cnt);
					//						add(new seText(str, cnt));
					else
						rtnstr += pbstr;
					l -= cnt;
					//str = ptr;
					str = str.Substring(ptr);
				}
			}
			//rtnstr = rtnstr.Replace("`", @"\'b0");			// convert backquote to degree - left over from DOS days.
			return rtnstr;
		}

		private string ProcessConditional(string cnd, string opt, int lencnd, int lenopt, bool multiRtnVal /*, DocVersionInfo docverinfo */)
		{
			// equaluate condition
			string stat = (docVerInfo != null) ? docVerInfo.Evaluate(cnd,lencnd) : "";
			int ls = stat.Length;//strlen(stat);
			if (ls == 0)
				return ""; // if evaluation not defined then return an empty string - no matches can be made
			// look for match - remember default
			string match = null;
			int matchlen = 0;
			string def = null;
			int deflen = 0;
			while (lenopt > 0 && match ==  null)
			{
			   int end = MatchingBrace(opt);
				int eq = opt.IndexOf('=');// strchr(opt, '=');
				int len = end + 1; //(int)((end + 1) - opt);	// +1 to include the '}'
				int li = eq - 1;//(int)(eq - opt) - 1;
			   int ld = len - li - 3;// One for '{', '=' and '}'
			   if (def ==  null || eq == 1) // (!def || eq == opt+1)
			   {
					def = opt.Substring(eq + 1); //def=eq+1;
			      deflen = ld;
			   }
			   if (ls == li && (stat.IndexOf(opt.Substring(1),li) > -1)) //(ls == li && !strncmp(stat, opt + 1, li))
			   {
					match = opt.Substring(eq + 1,ld);// match = eq + 1;
			      matchlen = ld;
			   }
				opt = opt.Substring(len); //opt += len;// point to the next piece
			   lenopt -= len;
			}
			// if match process option - or process default
			if (match == null) //(!match)
			{
			   match = def.Substring(0,deflen);
			   matchlen = deflen;
			}
			return ProcessRO(match, multiRtnVal /*, docverinfo */); //process(match, matchlen);
		}

		private string ProcessBrace(string str, int l, ref bool nfnd, bool multiRtnVal /*, DocVersionInfo docverinfo */)
		{
			string rtnstr = "";
			int nxt = NextDelimiter("{=", str); //nextDelimiter("{=", str, l);
			if (nxt == -1) // no delimiter found
			{ // VarUse
				//strList *found=vl->lookFor(str,l);
				bool found = DictROVar.ContainsKey(str);
				if (found)
					rtnstr = DictROVar[str];
				//add(new seVarUse(found));
				else
					nfnd = true;
			}
			else
			{
				if (str[nxt] == '{')
				{ // conditonal or menu
					if (nxt == 0) // if (nxt == str)
					{ // menu
						// TODO: implement Menu logic
						//ml->process(str, l, vl);
						//add(new seMenuUse(ml));
						//lstRoValues.Add(ProcessRO(str.Substring(0,l), true));
						ProcessMultiReturnValues(str, l);
					}
					else
					{ // conditional
						rtnstr = ProcessConditional(str, str.Substring(nxt), nxt, str.Length - nxt - 1, multiRtnVal /*, docverinfo */);//processCondition(str, nxt, (int)(nxt - str), l - (int)(nxt - str));
					}
				}
				else
				{ // must be variable definiton
					//vl->add(str, nxt+1, (int)(nxt-str), (l - (int)(nxt-str))-1, ml);

					// 'l' is the lenght up to the matching brace of the variable definition
					string tmpval = ProcessRO(str.Substring(nxt + 1, l - nxt - 1), multiRtnVal /*,docverinfo */);
					if (tmpval.Equals(string.Empty)) tmpval = " "; // nothing assinged to variable
					DictROVar.Add(str.Substring(0, nxt), tmpval);
					if (multiRtnVal)
						rtnstr = tmpval;
				}
			}
			return rtnstr;
		}

		private void ProcessMultiReturnValues(string str, int len)
		{
			string tstr = str.Substring(0, len);
			while (tstr.Length > 0)
			{
				int idx = MatchingBrace(tstr);
				lstRoValues.Add(ProcessRO(tstr.Substring(0,idx+1),true));
				tstr = tstr.Substring(idx+1);
			}
		}


		private int MatchingBrace(string str)
		{
			int level = 1;
			int idx = 0; // the while will skip the first position (the first brace)
			while (level > 0 && idx++ < str.Length)
			{
				switch (str[idx])
				{
					case '{':
						level++;
						break;
					case '}':
						level--;
						break;
				}
			}
			if (level != 0)
				idx = -1; // didn't find matching brace

			return idx; //length including end brace
		}

		private int NextDelimiter(string delim, string str)
		{
			int idx;
			idx = str.IndexOfAny(delim.ToCharArray());
			return idx;
		}

	}
}