/*
    * This file is a part of CAST project.
    * (c) Copyright 2007, AGH University of Science & Technology
    * https://caribou.iisg.agh.edu.pl/trac/cast
    *
    * Licensed under the Eclipse Public License, Version 1.0 (the "License").
    * You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * http://www.eclipse.org/legal/epl-v10.html
   */
  /*
   * File: Link.java
   * Created: 2007-09-19
   * Author: apohllo
   * $Id: Link.java 2361 2009-01-18 20:03:25Z awos $
   */
  
  package pl.edu.agh.cast.model.mapper;
  
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.sql.Types;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * The link represents the raw connection between nodes in the base model.
   *
   * @author AGH CAST Team
   */
  public class Link {
  
      /**
       *
       */
      private static final String SELECT_FIELDS = "SELECT id, src_id, dst_id, priority, name, " + //$NON-NLS-1$
              "src_accessor, dst_accessor, src_position, dst_position "; //$NON-NLS-1$
  
      /**
       *
       */
      private static final String DST_POSITION_FIELD = "dst_position"; //$NON-NLS-1$
  
      /**
       *
       */
      private static final String SRC_POSITION_FIELD = "src_position"; //$NON-NLS-1$
  
      private Node source;
  
      private long sourceId;
  
      private Node destination;
  
      private long destinationId;
  
      private String name;
  
      private String sourceAccessor;
  
      private String destinationAccessor;
  
      private int priority;
  
      private long id;
  
      private int srcPosition = 0;
  
      private int dstPosition = 0;
  
      private boolean saved;
  
      private static Mapper mapper = Mapper.getInstance();
  
      private static Map<Long, Link> linkCache = Collections.synchronizedMap(new HashMap<Long, Link>());
  
      // ////////////////////////////////////////////////////////////////
      // Constructors
      // ////////////////////////////////////////////////////////////////
  
      /**
       * Creates the link from key : value pairs.
       *
       * @param args
       *            the map of key : value pairs.
       */
      public Link(Map args) {
          JRubyIntegration.stringifyKeys(args);
          int srcPos = 0;
          if (args.containsKey(SRC_POSITION_FIELD)) {
              srcPos = ((Long)args.get(SRC_POSITION_FIELD)).intValue();
          }
          int dstPos = 0;
          if (args.containsKey(DST_POSITION_FIELD)) {
             dstPos = ((Long)args.get(DST_POSITION_FIELD)).intValue();
         }
 
         initialize((Node)args.get("src"), (Node)args.get("dst"), //$NON-NLS-1$ //$NON-NLS-2$
                 (String)args.get("name"), translatePriority(args //$NON-NLS-1$
                         .get("priority")), (String)args.get("src_accessor"), //$NON-NLS-1$ //$NON-NLS-2$
                 (String)args.get("dst_accessor"), srcPos, dstPos); //$NON-NLS-1$
     }
 
     /**
      * Creates the link from given set of attributes.
      *
      * @param src
      *            The source of the link
      * @param dst
      *            The target of the link
      * @param name
      *            The name of the link
      * @param priority
      *            The priority of the link
      */
     public Link(Node src, Node dst, String name, int priority) {
         initialize(src, dst, name, priority, null, null, 0, 0);
     }
 
     /**
      * Lazy binding constructor.
      *
      * @param srcId
      *            The id of the source node
      * @param dstId
      *            The id of the destination node
      * @param name
      *            The name of the link
      * @param priority
      *            The priority of the link
      */
     public Link(long srcId, long dstId, String name, int priority) {
         sourceId = srcId;
         destinationId = dstId;
         initialize(null, null, name, priority, null, null, 0, 0);
     }
 
     public Link(Node src, Node dst, String name, Priority priority, String srcAccessor, String dstAccessor) {
         initialize(src, dst, name, priority.ordinal(), srcAccessor, dstAccessor, 0, 0);
     }
 
     public Link(Node src, Node dst, String name, Priority priority) {
         initialize(src, dst, name, priority.ordinal(), null, null, 0, 0);
     }
 
     public Link(Node src, Node dst, String name, Priority priority, String srcAcc, String dstAcc, int srcPosition,
             int dstPosition) {
         initialize(src, dst, name, priority.ordinal(), srcAcc, dstAcc, srcPosition, dstPosition);
     }
 
     private void initialize(Node src, Node dst, String newName, int newPriority, String newSrcAccessor,
             String newDstAccessor, int newSrcPosition, int newDstPosition) {
         setSrc(src);
         if (src != null) {
             src.addSrcLink(this);
         }
         setDst(dst);
         if (dst != null) {
             dst.addDstLink(this);
         }
         name = newName;
         priority = newPriority;
         sourceAccessor = newSrcAccessor;
         destinationAccessor = newDstAccessor;
         srcPosition = newSrcPosition;
         dstPosition = newDstPosition;
     }
 
     private static PreparedStatement findWithDstStmt;
 
     private static PreparedStatement findWithSrcStmt;
 
     private static PreparedStatement findStmt;
 
     private static PreparedStatement saveStmt;
 
     static {
         String stmtStr;
         try {
             stmtStr = SELECT_FIELDS + "FROM links WHERE dst_id = ? ORDER BY src_position"; //$NON-NLS-1$
             findWithDstStmt = mapper.getConnection().prepareStatement(stmtStr);
 
             stmtStr = SELECT_FIELDS + " FROM links WHERE src_id = ? ORDER BY dst_position"; //$NON-NLS-1$
             findWithSrcStmt = mapper.getConnection().prepareStatement(stmtStr);
 
             stmtStr = SELECT_FIELDS + " FROM links WHERE id = ?"; //$NON-NLS-1$
             findStmt = mapper.getConnection().prepareStatement(stmtStr);
 
             stmtStr = "INSERT INTO links SET name = ?, src_id = ?, " //$NON-NLS-1$
                     + "dst_id = ?, priority = ?, src_accessor = ?, " //$NON-NLS-1$
                     + "dst_accessor = ?, src_position = ?, dst_position = ? "; //$NON-NLS-1$
             saveStmt = mapper.getConnection().prepareStatement(stmtStr, Statement.RETURN_GENERATED_KEYS);
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 
     /**
      * Save given metamodel link in the DB.
      *
      * <p>
      * The saving process is recursive. Source and destination nodes are saved first and then the link is saved.
      * </p>
      *
      * @return True if the save was successful (or link has been saved earlier).
      */
     public boolean save() {
         if (saved) {
             return true;
         }
 
         // System.out.println("Save link")
 
         // validation
         if (name == null || name.equals("")) { //$NON-NLS-1$
             throw new RuntimeException("Link's name must not be blank: " + this); //$NON-NLS-1$
         }
 
         if (getSrc() == null) {
             throw new RuntimeException("Link's src must not be null: " + this); //$NON-NLS-1$
         }
 
         if (getDst() == null) {
             throw new RuntimeException("Link's dst must not be null: " + this); //$NON-NLS-1$
         }
 
         try {
             if (id == 0) {
                 // new node
 
                 saveStmt.setString(1, name);
 
                 setSaved(true);
                 long srcId = getSrc().getId();
                 if (srcId == 0) {
                     if (!getSrc().save()) {
                         setSaved(false);
                         return false;
                     }
                     srcId = getSrc().getId();
                     if (srcId == 0) {
                         throw new RuntimeException("Node id is 0: " + getSrc()); //$NON-NLS-1$
                     }
 
                 }
                 saveStmt.setLong(2, srcId);
 
                 long dstId = getDst().getId();
                 if (dstId == 0) {
                     if (!getDst().save()) {
                         setSaved(false);
                         return false;
                     }
                     dstId = getDst().getId();
                     if (dstId == 0) {
                         throw new RuntimeException("Node id is 0: " + getDst()); //$NON-NLS-1$
                     }
 
                 }
                 saveStmt.setLong(3, dstId);
 
                 saveStmt.setInt(4, getPriority());
 
                 String srcAccessor = getSrcAccessor();
                 if (srcAccessor != null) {
                     saveStmt.setString(5, srcAccessor);
                 } else {
                     saveStmt.setNull(5, Types.VARCHAR);
                 }
 
                 String dstAccessor = getDstAccessor();
                 if (dstAccessor != null) {
                     saveStmt.setString(6, dstAccessor);
                 } else {
                     saveStmt.setNull(6, Types.VARCHAR);
                 }
 
                 saveStmt.setInt(7, getSrcPosition());
                 saveStmt.setInt(8, getDstPosition());
 
                 saveStmt.executeUpdate();
                 ResultSet rs = saveStmt.getGeneratedKeys();
                 if (rs.next()) {
                     setId(rs.getLong(1));
                     setSaved(true);
                 } else {
                     throw new SQLException("Cannot obtain the last link id"); //$NON-NLS-1$
                 }
                 return true;
             }
         } catch (SQLException e) {
             System.err.println(e.getMessage());
             setSaved(false);
             return false;
         }
 
         return false;
     }
 
     // ////////////////////////////////////////
     // priority
     // ////////////////////////////////////////
     /**
      * Priority reader.
      *
      * @return Priority value
      */
     public int getPriority() {
         return priority;
     }
 
     /**
      * Priority setter.
      *
      * @param newPriority
      *            priority value
      */
     public void setPriority(int newPriority) {
         priority = newPriority;
     }
 
     /**
      * Priority setter (tries to translate given object to priority).
      *
      * @param priority
      *            priority value
      */
     public void setPriority(Object priority) {
         setPriority(translatePriority(priority));
     }
 
     private int translatePriority(Object priorityObj) {
         int priorityValue = 0;
         if (priorityObj != null) {
             if (priorityObj.toString().equals("src_over_dst")) {
                 priorityValue = 1;
             } else if (priorityObj.toString().equals("dst_over_src")) {
                 priorityValue = 2;
             }
         }
         return priorityValue;
     }
 
     // //////////////////////////////////////////////////
     // Source and destination
     // //////////////////////////////////////////////////
     /**
      * Destination node getter. Due to DB load optimization, must be used internally as well.
      *
      * @return Destination metamodel node
      */
     public Node getDst() {
         if (destination == null && destinationId != 0) {
             destination = Node.find(destinationId);
         }
         return destination;
     }
 
     /**
      * The destination id getter.
      *
      * @return The destination id.
      */
     public long getDstId() {
         if (destinationId == 0 && destination != null) {
             destinationId = destination.getId();
         }
         return destinationId;
     }
 
     /**
      * Source node getter. Due to DB load optimization, must be used internally as well.
      *
      * @return Source metamodel node
      */
     public Node getSrc() {
         if (source == null && sourceId != 0) {
             source = Node.find(sourceId);
         }
         return source;
     }
 
     /**
      * The source id getter.
      *
      * @return The source id.
      */
     public long getSrcId() {
         if (sourceId == 0 && source != null) {
             sourceId = source.getId();
         }
         return sourceId;
     }
 
     /**
      * DB indentifier reader.
      *
      * @return DB identifier
      */
     public long getId() {
         return id;
     }
 
     /**
      *
      * {@inheritDoc}
      *
      * @see java.lang.Object#toString()
      */
     @Override
     public String toString() {
         StringBuilder builder = new StringBuilder();
         builder.append("Link: "); //$NON-NLS-1$
         builder.append(name);
         builder.append(" ["); //$NON-NLS-1$
         builder.append(id);
         builder.append(", "); //$NON-NLS-1$
         builder.append(priority);
         builder.append("] src "); //$NON-NLS-1$
         builder.append(getSrcId());
         builder.append(" ["); //$NON-NLS-1$
         builder.append(getSrcPosition());
         builder.append("] dst "); //$NON-NLS-1$
         builder.append(getDstId());
         builder.append(" ["); //$NON-NLS-1$
         builder.append(getDstPosition());
         builder.append("]"); //$NON-NLS-1$
         return builder.toString();
     }
 
     /**
      * Name getter.
      *
      * @return Name of the link
      */
     public String getName() {
         return name;
     }
 
     /**
      * Source setter.
      *
      * @param srcNode
      *            Node to be set as source of the link
      */
     public void setSrc(Node srcNode) {
         source = srcNode;
         if (source != null) {
             sourceId = source.getId();
         }
     }
 
     /**
      * Destination setter.
      *
      * @param dst
      *            Node to be set as desitintion of the link
      */
     public void setDst(Node dst) {
         destination = dst;
         if (destination != null) {
             destinationId = destination.getId();
         }
     }
 
     /**
      *
      * {@inheritDoc}
      *
      * @see java.lang.Object#equals(java.lang.Object)
      */
     @Override
     public boolean equals(Object other) {
         if (this == other) {
             return true;
         }
 
         if (!(other instanceof Link)) {
             return false;
         }
 
         Link that = (Link)other;
 
         // srcAccessor may be null
         if (this.sourceAccessor == null) {
             if (that.sourceAccessor != null) {
                 return false;
             }
         } else {
             if (!this.sourceAccessor.equals(that.sourceAccessor)) {
                 return false;
             }
         }
 
         // dstAccessor may be null
         if (this.destinationAccessor == null) {
             if (that.destinationAccessor != null) {
                 return false;
             }
         } else {
             if (!this.destinationAccessor.equals(that.destinationAccessor)) {
                 return false;
             }
         }
 
         return this.id == that.id && this.getDstId() == that.getDstId() && this.getSrcId() == that.getSrcId()
                 && this.name.equals(that.name) && this.priority == that.priority
                 && this.srcPosition == that.srcPosition && this.dstPosition == that.dstPosition;
     }
 
     /**
      * Find link with given id of null if not present.
      *
      * @param linkId
      *            The id of the link
      * @return Link with given id or null
      */
     public static Link find(long linkId) {
         // System.out.println("Find link "+linkId);
         Link link;
 
         // try cache first
         link = linkCache.get(linkId);
         if (link != null) {
             return link;
         }
 
         try {
             findStmt.setLong(1, linkId);
             ResultSet rs = findStmt.executeQuery();
 
             if (rs.next()) {
                 link = createLink(rs, 0);
             } else {
                 return null;
             }
             return link;
 
         } catch (SQLException e) {
             e.printStackTrace();
         } finally {
             try {
                 findStmt.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
 
         return null;
     }
 
     /**
      * Creates link based on the data found in the DB. The link cache is consulted first to ensure referential integrity
      * (i.e. link with the same id are created only once). TODO cache invalidation (needed?)
      *
      * @param resultSet
      *            The data to be used to create the link
      * @return New link initialized with the data stored in the DB.
      * @throws SQLException
      */
     static Link createLink(ResultSet resultSet, int fieldOffset) throws SQLException {
         long linkId = resultSet.getLong(fieldOffset + 1);
         Link link;
 
         // try link cache first
         link = linkCache.get(linkId);
         if (link != null) {
             return link;
         }
 
         link = new Link(resultSet.getLong(fieldOffset + 2), resultSet.getLong(fieldOffset + 3), resultSet
                 .getString(fieldOffset + 5), resultSet.getInt(fieldOffset + 4));
         link.setId(linkId);
         link.setSaved(true);
         link.setSrcAccessor(resultSet.getString(fieldOffset + 6));
         link.setDstAccessor(resultSet.getString(fieldOffset + 7));
         link.setSrcPosition(resultSet.getInt(fieldOffset + 8));
         link.setDstPosition(resultSet.getInt(fieldOffset + 9));
         linkCache.put(linkId, link);
         return link;
     }
 
     public void setSrcPosition(int position) {
         srcPosition = position;
     }
 
     /**
      * The position of source node among other nodes at the source side of the relationship (set of links).
      *
      * @return The position of the source node.
      */
     public int getSrcPosition() {
         return srcPosition;
     }
 
     /**
      * The target position setter.
      *
      * @param position
      *            The position to set.
      */
     public void setDstPosition(int position) {
         dstPosition = position;
     }
 
     /**
      * The position of destination node among other nodes at the destination side of the relationship (set of links).
      *
      * @return The position of the target node.
      */
     public int getDstPosition() {
         return dstPosition;
     }
 
     /**
      * The hash code.
      *
      * @return hash code
      */
     @Override
     public int hashCode() {
         int value = (int)(name.hashCode() ^ priority + (id * 7) ^ (getSrcId() * 17) ^ (getDstId() * 19)
                 ^ (srcPosition * 11) ^ (dstPosition * 23));
         if (sourceAccessor != null) {
             value ^= sourceAccessor.hashCode();
         } else {
             value += 100000;
         }
         if (destinationAccessor != null) {
             value ^= destinationAccessor.hashCode();
         } else {
             value += 200;
         }
 
         return value;
     }
 
     /**
      * Returns the name of the source node accessor method.
      *
      * @return Source node getter
      */
     public String getSrcAccessor() {
         return sourceAccessor;
     }
 
     /**
      * Returns the name of the destination node accessor method.
      *
      * @return Destination node getter
      */
     public String getDstAccessor() {
         return destinationAccessor;
     }
 
     /**
      * Saved flag setter.
      *
      * @param newSaved
      *            New saved value.
      */
     public void setSaved(boolean newSaved) {
         saved = newSaved;
     }
 
     /**
      * Id setter.
      *
      * @param newId
      *            New id
      */
     public void setId(long newId) {
         id = newId;
     }
 
     /**
      * Source accessor setter.
      *
      * @param accessor
      *            The source accessor.
      */
     public void setSrcAccessor(String accessor) {
         sourceAccessor = accessor;
     }
 
     /**
      * Target accessor setter.
      *
      * @param accessor
      *            The target accessor.
      */
     public void setDstAccessor(String accessor) {
         destinationAccessor = accessor;
     }
 
     /**
      * Find link which is equal to given link.
      *
      * @param link
      *            The link which is used as the query example.
      * @return The link with the same id.
      */
     public static Link find(Link link) {
         return find(link.getId());
     }
 
     /**
      * Find all link whose source is a node with given id.
      *
      * @param nodeId
      *            The id of the source node
      * @return List of links
      * @throws SQLException
      */
     public static List<Link> findWithSrc(long nodeId) throws SQLException {
 
         findWithSrcStmt.setLong(1, nodeId);
         ResultSet rs = findWithSrcStmt.executeQuery();
         List<Link> result = new LinkedList<Link>();
         while (rs.next()) {
             result.add(createLink(rs, 0));
         }
         return result;
     }
 
     /**
      * Find all link whose destination is a node with given id.
      *
      * @param nodeId
      *            The id of the destination node
      * @return List of links
      * @throws SQLException
      */
     public static List<Link> findWithDst(long nodeId) throws SQLException {
         findWithDstStmt.setLong(1, nodeId);
         ResultSet rs = findWithDstStmt.executeQuery();
         List<Link> result = new LinkedList<Link>();
         while (rs.next()) {
             result.add(createLink(rs, 0));
         }
         return result;
     }
 
     /**
      * Print out the stats of the link cache.
      */
     public static void stats() {
         // TODO DO NOT USE PRINTLN
         // System.out.println("Link cache " + _linkCache.size());
     }
 
     static void clearCache() {
         linkCache.clear();
     }
 
 }