//package Persistent_Object;

import java.util.Vector;

/**
 *
 * PO_CommandConstructor Class
 *
 * This is a class which prepares the command/instructions
 * that are sent to the network server.
 *
 * @version 1.3 Mar 1997
 * @author  Francis Chan
 */

public class PO_CommandConstructor{

  private String commandStr = null;
  //private PersistentObject po;
  private boolean debugFlag = true;


  /**
   * Constructor for PO_CommandConstructor
   */

  public PO_CommandConstructor(){

    //this.po = po;
  }

  /**
   *
   * Handles the construction of strings for multiple commands
   *
   * @param mode            Mode of operation
   * @param userId          DB identifier string
   * @param objectClassName Class Name of the object
   * @param objId           Integer Id of the object
   * @param objectStrId     String Id of the object
   * @param childId         Id of the child object
   * @param relationship    PO.PARENTS or PO.CHILDREN
   * @param version         Versiong of the object requested, 
   *                        A.B, or
   *                        "R" for last-Release or
   *                        "L" for latest version
   */

  public String prepareCommandString(int mode, String userId,
				     String objectClassName,
				     int objId, String objectStrId,
				     int childId, int relationship,
				     String version){

    switch (mode) {
    case PO.GETSTR:
      commandStr = "GETSTR\n\r";
      break;

   case PO.GETID:
      commandStr = "GETID\n\r";
      break;

   case PO.GETVERID:
      commandStr = "GETVERID\n\r";
      break;

    case PO.DELETE:
      commandStr = "DELETE\n\r";
      break;

    case PO.CONNECT:
      commandStr = "CONNECT\n\r";
      break;

    case PO.DISCONNECT:
      commandStr = "DISCONNECT\n\r";
      break;

    case PO.GETATTINFO:
      commandStr = "GETATTINFO\n\r";
      break;
    }

    commandStr += userId;
    commandStr += "\n\r";

    // slight differences for the Connect and Disconnect commands
    if ((mode == PO.CONNECT) || (mode == PO.DISCONNECT))
      commandStr += objId;
    else commandStr += objectClassName;
    commandStr += "\n\r";

    if ((mode == PO.CONNECT) || (mode == PO.DISCONNECT))
      commandStr += childId;
    else if (mode == PO.GETSTR)
      commandStr += objectStrId;
    else commandStr += objId;

    // added information needed for the GetAttInfo command
    if (mode == PO.GETATTINFO) {
      if (relationship == PO.PARENTS)
    	commandStr += "\n\rCONTAINER\n\r";
      else commandStr += "\n\rCONTENTS\n\r";
      commandStr += childId;
    }

    // added information needed for the GetVerId command
    if (mode == PO.GETVERID) {
      commandStr += "\n\r";
      commandStr += version;
    }

    commandStr += "\n\r\n\r";

    DEBUG("\n" + commandStr);

    return commandStr;
  }


  /**
   *
   * Prepare a Stream that contains the processed fields of the
   * object, used primary for saving objects
   *
   * @param mode            Mode of operation (see PO.java)
   * @param userId          DB identifier string
   * @param objectClassName Class Name of the object
   * @param objId           Integer Id of the object
   * @param objectStrId     String Id of the object
   * @param fieldVector     Vector of the Object's fields info
   * @param fieldTypeArray  Array of the Object's fields' types
   */

  public String prepareSaveString(int mode, String userId,
                                  String objectClassName,
                                  int objId, String objectStrId,
                                  Vector fieldVector,
                                  int[] fieldTypeArray,
				  int versionFlag){

    // will use simple String for now
    // will investigate the use of more complicated structures
    // such as DataInputStream in the future

    switch (mode) {

    case PO.PUT:
      commandStr = "PUT\n\r";
      break;

    case PO.MODIFY:
      commandStr = "MODIFY\n\r";
      break;

    case PO.PUTVER:
      commandStr = "PUTVER\n\r";
      break;
    }

    commandStr += userId;
    commandStr += "\n\r";
    commandStr += objectClassName;
    commandStr += "\n\r";

    if (mode == PO.MODIFY){
      commandStr += objId;
      commandStr += "\n\r";
    }

   // processing the fieldVector
    for (int i=0; i<fieldVector.size(); i++){

      switch (fieldTypeArray[i]) {

      case PO.STRING:
	String str = (String) fieldVector.elementAt(i);

	// set "NULL" for a null String to preserve
	// format of the string sent and received
	
	if ((str == null) || (str.trim().length() == 0) ||
	    (str.compareTo("\n") == 0)) {
	  commandStr = commandStr.concat("NULL");
	} else {
	  commandStr = commandStr.concat(str);
	}
	commandStr += "\n\r";
	   break;

      case PO.INT:
	String intStr = ((Integer) fieldVector.elementAt(i)).toString();
	commandStr = commandStr + intStr;
	commandStr += "\n\r";
	break;
	
      case PO.DOUBLE:
	String doubleStr = ((Double) fieldVector.elementAt(i)).toString();
	commandStr = commandStr + doubleStr;
	commandStr += "\n\r";
	break;
	
      case PO.CHAR:
	char charValue = ((String) fieldVector.elementAt(i)).charAt(0);
	commandStr = commandStr + charValue;
	commandStr += "\n\r";
	break;
	
      case PO.BOOLEAN:
	commandStr = commandStr.concat((String) fieldVector.elementAt(i));
	commandStr += "\n\r";
	break;
	
      case PO.FLOAT:
	commandStr = commandStr.concat(((Float)
					fieldVector.elementAt(i)).toString());
	commandStr += "\n\r";
	break;
	
      case PO.ARRAY:
	double[] array = (double[]) fieldVector.elementAt(i);
	
	int numEle = (int) array[0]; // number of elements in the array

	commandStr += numEle;
	commandStr += " ";

	// contents start from 1
	for (i=1; i<=numEle; i++) {
	  commandStr += array[i];
	  commandStr += " ";
	}
	commandStr += "\n\r";
	break;
	
	// do nothing in the 1st level message
	// load the object after receiving 1st-level object's ID and
	// then do the attach/assignment
	
      case PO.VECTOR:
      case PO.OBJECT:
      case PO.UNIQUE_ID:
      case PO.CHILDREN:
	break;
      }
    }

    if (mode == PO.PUTVER){
      if (versionFlag == PO.POINT_VERSION)
	commandStr += "P";
      else commandStr += "T";
      commandStr += "\n\r";
    }

    // last one to indicate end of String
    commandStr = commandStr.concat("\n\r");

    DEBUG("\n" + commandStr);

    // figuring out the length of String and add it in the message
    // for verification purposes can be added in in the future

    return commandStr;

  }

  /**
   *
   * Handles the construction of strings for directory commands
   *
   * @param op              Operation
   * @param userId          DB identifier string
   * @param objectClassName Class Name of the object
   * @param objId           Integer Id of the object
   */

  public String prepareDirCommandString(int op, String userId,
					String objectClassName,
					int objId) {

    if (op == PO.GETROOTDIR)
      commandStr = "GETROOTDIR\n\r";
    else commandStr = "GETCONTEXT\n\r";

    commandStr += userId;
    commandStr += "\n\r";

    if (op == PO.GETROOTDIR){
      commandStr += "\n\r";
      DEBUG("\n" + commandStr);
      return commandStr;
    }

    else{
      commandStr += objectClassName;
      commandStr += "\n\r";

      commandStr += objId;
      commandStr += "\n\r\n\r";

      DEBUG("\n" + commandStr);
      return commandStr;
    }
  }

  /**
   *
   * Handles the construction of strings for query commands
   *
   * @param op              Operation
   * @param userId          DB identifier string
   * @param objectClassName Class Name of the object
   * @param scope           Scope of the search
   * @param fieldName Class fieldName of the search
   * @param objId           Integer Id of the object
   */

  public String prepareQueryCommandString(int op, String userId,
					  String objectClassName,
					  int scope,
					  String fieldName, String strId) {

    commandStr = "QUERY\n\r";
    commandStr += userId;
    commandStr += "\n\r";
    commandStr += objectClassName;
    commandStr += "\n\r";

    switch (scope) {

      case (QueryObject.GLOBAL):
	commandStr += "G";
      break;
      case (QueryObject.CLASS):
	commandStr += "C";
      break;
      case (QueryObject.DATABASE):
	commandStr += "D";
      break;
    }
    commandStr += "\n\r";
    commandStr += "F\n\r";  // currently only supports search by field name
    commandStr += fieldName;
    commandStr += "\n\r";
    commandStr += strId;
    commandStr += "\n\r\n\r";

    DEBUG("\n" + commandStr);
    return commandStr;
  }

  /**
   *
   * Debug
   * Prints debugging statements if the debug flag is set to true
   *
   * @param debugStmt The debugging statement supplied
   */

  static private void DEBUG(String debugStmt){

    if (PersistentObject.debugFlag == true) {
      System.out.println("PO_CommandConstructor: " + debugStmt);
    }
  }

}