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package eg.edu.alexu.csd.oop.db;
import com.sun.xml.internal.bind.v2.runtime.unmarshaller.XsiNilLoader;
import java.io.FileNotFoundException;
import java.sql.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.xml.stream.XMLStreamException;

/**
 *
 * @author Mustafa
 */
public class SQL {
 final  Pattern createtable;
   final Pattern droptable ;
   final Pattern insertinto ;
   final Pattern deletefrom ;
   final Pattern select ;
     Pattern []patternarray = new Pattern[5] ;

    public SQL(){

        this.createtable = Pattern.compile("(?i)create\\s+table\\s+\\w+\\s*(.*);");
        this. droptable = Pattern.compile("(?i)drop\\s+table\\s+\\w+\\s*;");
        this.insertinto = Pattern.compile("(?i)insert\\s+into\\s+\\w+\\s*(.*)values\\s*(.*);");
        this.deletefrom = Pattern.compile("(?i)delete\\s+from\\s+\\w+\\s*where\\s*(.*);");
            this.select = Pattern.compile("(?i)select\\s*(.*)\\s*from\\s+\\w+\\s*(where\\s*(.*));");

      patternarray[0] = createtable;
      patternarray[1] = droptable;
      patternarray[2] = insertinto;
      patternarray[3] = deletefrom;
      patternarray[4] = select;

    }


 public void query (String query) throws XMLStreamException, FileNotFoundException{

     StringTokenizer token = new StringTokenizer(query);
     StringBuilder std = new StringBuilder();
     while (token.hasMoreTokens()){
         std.append(token.nextToken());
         std.append(" ");

     }

     for (int i = 0 ;i <patternarray.length;i++){
        // System.out.println(std.toString());
          Matcher m = patternarray[i].matcher(std.toString());

               if (m.find()){
                //   System.out.println(i);
// method i
CaptureTheQuery(i,std.toString());
               }
     }


 }

public void CaptureTheQuery(int i, String query) throws XMLStreamException, FileNotFoundException {

        switch (i) {
            case 0:
/*
                Matcher matcher = Pattern.compile("CREATE\\s+TABLE\\s+\"?(\\w+)").matcher(query);
                if (matcher.find()) {
                    String name = matcher.group(1);
                    //System.out.print(name);
                }*/
                String name = null;
                Matcher matcher = Pattern.compile("(?i)\\s*CREATE\\s+TABLE?\\s+(\\w+)").matcher(query);
                if (matcher.find()) {
                     name = matcher.group(1);
                 //  System.out.print(name + "\n");
                }
                StringBuilder a = new StringBuilder();
                boolean paren = false;
                for (char ch: query.toCharArray())
                {
                   if(ch == '(')
                   paren = true;
                   if(ch == ')')
                   paren = false;
                      if(paren == true&& ch !='(' && ch != '\n'  && ch!= '\t')
                      {
                          a.append(ch);
                      }


                }
               // System.out.println(a.toString());
          //     String subject = "HELLO , THERE ,WORLD";
                String[] couple = a.toString().split(",");
               String[] column_name = new String[couple.length];

                String[] data_types = new String[couple.length];

               for(int z=0; z<couple.length; z++)
               {
                  //  System.out.print(couple[z]);
               Matcher iii = Pattern.compile("(?i)(\\w+)\\s*(\\w+)").matcher(couple[z]);
                // System.out.print(couple[z]);
                if (iii.find()) {
                   column_name[z] = iii.group(1);
                   data_types[z]  = iii.group(2);
                }
              //  System.out.println(column_name[z]);
           //  column_name[z] = matcher.group(1);
             // data_types[z] = matcher.group(2);
               }
             //  System.out.println(Arrays.toString(data_types) +" "+ Arrays.toString(column_name)  );
               List<Map<String, String>> Data = new ArrayList();
              Controller.controller().Create(name, Data);
           //     System.out.println(name + " created successfully ");

                // creat table
                break;
            case 1:
           matcher = Pattern.compile("(?i)\\s*DROP\\s+TABLE?\\s+(\\w+);").matcher(query);

                 if (matcher.find()) {
                     name = matcher.group(1);
                     Controller.controller().Drop(name);
                 //   System.out.print(name+ " Dropped");
                }



// drop table

                break;
            case 2:


                // insert into table

                int parenth_lvl = 0;
                a = new StringBuilder();
                StringBuilder b =  new StringBuilder();
                 matcher = Pattern.compile("(?i)\\s*INSERT\\s*INTO\\s*(\\w+)\\s*").matcher(query);

                if (matcher.find()) {
                     name = matcher.group(1);
                    for (char ch: query.toCharArray())
                {
                   if(ch == '(')
                   parenth_lvl++;
                   if(ch == ')')
                   {
                    parenth_lvl++;
                   }
                      if(parenth_lvl ==1&& ch !='(' && ch != '\n' && ch != ' '  && ch!= '\t')
                      {
                          a.append(ch);
                      }
                        if(parenth_lvl ==3&& ch !='(' && ch != '\n' && ch != ' '  && ch!= '\t')
                      {
                         b.append(ch);
                      }

                }
                    String[] Columns = a.toString().split(",");
                    String[] Values = b.toString().split(",");
                    Map<String,String> new_data = new LinkedHashMap<String,String>();
                    for( i =0; i<Columns.length;i++ )
                    {
                        new_data.put(Columns[i], Values[i]);
                    }


                      Controller.controller().Insert(name, new_data);
                  //  System.out.println(Arrays.toString(Values) +" " + Arrays.toString(Columns));

                }




                break;
            case 3:
                // delete from

                 matcher = Pattern.compile("(?i)\\s*DELETE\\s+FROM\\s*(\\w+)\\s*where\\s*(\\w+)\\s*(=|<|>)\\s*(\\w+)\\s*;").matcher(query);
                if (matcher.find()) {
                     name = matcher.group(1);
                    String op = matcher.group(3);
                    String LHS = matcher.group(2);
                     String RHS = matcher.group(4);

                     //Delete (String tableName ,char operator, String col, String val )
                     char[] operand = op.toCharArray();
                       System.out.print( name + " " +LHS + " "+op  + " " + RHS );
                      Controller.controller().Delete(name, operand[0], LHS, RHS);

                }


                break;
            case 4:
                // selsct from
                matcher = Pattern.compile("(?i)\\s*SELECT\\s*((\\w+),\\s*|(\\w+))*\\s*FROM\\s*(\\w+)\\s*WHERE\\s*(\\w+)\\s*(=|<|>)\\s*(\\w+)\\s*;").matcher(query);
                if (matcher.find()) {
                     name = matcher.group(4);
                    String op = matcher.group(6);
                    String LHS = matcher.group(5);
                     String RHS = matcher.group(7);
              //    System.out.print( name + " " +LHS + " "+op  + " " + RHS );
                     // System.out.print( Arrays.toString(Columns_names) );
                a= new StringBuilder();
                b= new StringBuilder();
                boolean flag = false;
                 for (char ch: query.toCharArray())
                {
                      a.append(ch);
                      if(flag == true && ch != ' ' )
                           b.append(ch);
                      if(a.toString().equalsIgnoreCase("select") )
                      {
                          flag = true;
                      }


                }
                  String[] Columns = b.toString().split(",");
                 matcher = Pattern.compile("(?i)\\s*(\\w+)\\s*FROM").matcher(Columns[Columns.length-1]);
                 if (matcher.find()) {
                    Columns[Columns.length-1] = matcher.group(1);
                }

                    //(String tableName, String[] columns, char operator, String col, String val)
                  char[]  operand = op.toCharArray();
                //   System.out.print( Arrays.toString(Columns) +name + RHS +operand[0] + LHS+ " " );
                      Controller.controller().Select(name, Columns ,operand[0] , LHS , RHS );
                }


                break;
        }

    }



}