import java.io.File;
   import java.util.Scanner;
   import java.util.ArrayList;
   import java.util.HashMap;
   import java.util.Stack;
    public class Parser
   {
       public static String[][] parse (String file) throws Exception
      {
         String[] ans;
         Scanner infile = new Scanner(new File(file));
        //remove newlines
         String help="";
         while(infile.hasNextLine())
            help+=infile.nextLine();
        //evaluate imports
         int t=help.indexOf("{import "),m,e;
         while(t>=0)
         {
            e=t+8;
            while(help.charAt(e)!='}')
               e++;
            //System.out.println(help.substring(t+8,e));
            infile = new Scanner(new File("imports/"+help.substring(t+8,e)+".nus"));
            String temp=help.substring(0,t);
            while(infile.hasNextLine())
               temp+=infile.nextLine();
            help=temp+help.substring(e+1);
            t=help.indexOf("{import ",t);
         }
         //log changes
         HashMap<String,String> vars=new HashMap<String,String>();
         t=help.indexOf("{def $");
         while(t>=0)
         {
            m=t+6;
            while(help.charAt(m)!=' ')
               m++;
            e=m+1;
            while(help.charAt(e)!='}')
               e++;
            vars.put(help.substring(t+6,m),help.substring(m+1,e));
            help=help.substring(0,t)+help.substring(e+1);
            t=help.indexOf("{def $",t);
         }
         //replace variables
         t=help.indexOf("$");
         while(t>=0)
         {
            t++;
            e=t;
            while(!vars.containsKey(help.substring(t,e)))
               e++;
            help=help.substring(0,t-1)+vars.get(help.substring(t,e))+help.substring(e);
            t=help.indexOf("$",t);
         }
      //break up into units
         ArrayList<String> helper=new ArrayList<String>();
         int s,f;
         s=help.indexOf('{');
         f=help.indexOf('}');
         while(s>=0)
         {
            helper.add(help.substring(s+1,f));
            help=help.substring(f+1);
            s=help.indexOf('{');
            f=help.indexOf('}');
         }
         ans=new String[helper.size()];
         helper.toArray(ans);
         //expand parenthesis
         Stack<ArrayList> st;
         ArrayList[] te=new ArrayList[ans.length];
         String ss;
         String[] sss;
         ArrayList ite;
         boolean wasClose=false;
         for(int i=0;i<ans.length;i++)
         {
            st=new Stack<ArrayList>();
            st.push(new ArrayList());
            ss="";
            t=ans[i].indexOf('(');
            if(t>=0)
            {
               for(int j=0;j<ans[i].length();j++)
               {
                  if(ans[i].charAt(j)=='(')
                  {
                     if(!ss.equals(""))
                     {
                        st.peek().add(ss);
                        ss="";
                     }
                     st.push(new ArrayList());
                     // if(wasClose)
                        // st.peek().add("(");
                     wasClose=false;
                  }
                  else if(ans[i].charAt(j)==')')
                  {
                     if(!ss.equals(""))
                     {
                        st.peek().add(ss);
                        ss="";
                     }
                     wasClose=true;
                     te[i]=st.pop();
                     st.peek().add(te[i]);
                  }
                  else if(ans[i].charAt(j)==',')
                  {
                     if(!ss.equals(""))
                     {
                        st.peek().add(ss);
                        ss="";
                     }
                     wasClose=false;
                  }
                  else
                  {
                     wasClose=false;
                     ss+=ans[i].charAt(j);
                  }
               }
               te[i]=st.pop();
            }
            else
            {
               te[i]=new ArrayList();
               te[i].add(ans[i]);
            }
         }
      	//expand mapping
         ArrayList<String> ans2al=new ArrayList<String>();
         for(int i=0;i<te.length;i++)
         {
            flatten((ArrayList)expandItem(te[i]),ans2al);
         }
         String[] ans2=new String[ans2al.size()];
         ans2al.toArray(ans2);
         String[][] ans3=new String[ans2.length][];
         for(int i=0;i<ans3.length;i++)
            ans3[i]=ans2[i].split(" ");
         return ans3;
      }
       public static void flatten(ArrayList a, ArrayList<String> b)
      {
         for(int i=0;i<a.size();i++)
            if(a.get(i).getClass().equals("".getClass()))
               b.add((String)(a.get(i)));
            else
               flatten((ArrayList)(a.get(i)),b);
      }
       public static Object link(Object a, Object b) //links 2 items together
      {
         if(a.getClass().equals("".getClass()))
         {
            if(b.getClass().equals("".getClass()))
               return a+" "+b;
            else
            {
               ArrayList aa=new ArrayList();
               ArrayList bb=new ArrayList();
               aa.add(a);
               bb.add(aa);
               bb.add(b);
               return expandItem(bb);
            }
         }
         else
         {
            if(b.getClass().equals("".getClass()))
            {
               ArrayList aa=new ArrayList();
               ArrayList bb=new ArrayList();
               bb.add(b);
               aa.add(a);
               aa.add(bb);
               return expandItem(bb);
            }
            else
            {
               ArrayList bb=new ArrayList();
               bb.add(a);
               bb.add(b);
               return expandItem(bb);
            }
         }
      }
       public static Object expandItem(Object xx)  //expands one item
      {
         if(xx.getClass().equals("".getClass()))
            return xx;
         ArrayList x=(ArrayList)xx;
         if(x.get(0).getClass().equals("".getClass()))
            return xx;
         if(x.size()<1)
            return x;
         ArrayList ans=(ArrayList)(x.remove(0)),temp,tt;
         while(x.size()>0)
         {
            temp=(ArrayList)(x.remove(0));
            if(temp.size()<=ans.size())
            {
               if(temp.size()>0)
                  for(int i=0;i<ans.size();i++)
                     ans.set(i,link(ans.get(i),temp.get(i%(temp.size()))));
            }
            else
            {
               tt=ans;
               ans=temp;
               temp=tt;
               if(temp.size()>0)
                  for(int i=0;i<ans.size();i++)
                     ans.set(i,link(temp.get(i%(temp.size())),ans.get(i)));
            }
         }
         return ans;
      }
   }