/*******************************************************************************
    * Copyright (c) 2010, 2012 Sonatype, Inc.
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Eclipse Public License v1.0
    * which accompanies this distribution, and is available at
    * http://www.eclipse.org/legal/epl-v10.html
    *
    * Contributors:
    *    Sonatype, Inc. - initial API and implementation
   *******************************************************************************/
  package org.eclipse.aether.artifact;
  
  import java.io.File;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * A skeleton class for artifacts.
   */
  public abstract class AbstractArtifact
      implements Artifact
  {
  
      private static final String SNAPSHOT = "SNAPSHOT";
  
      private static final Pattern SNAPSHOT_TIMESTAMP = Pattern.compile( "^(.*-)?([0-9]{8}\\.[0-9]{6}-[0-9]+)$" );
  
      public boolean isSnapshot()
      {
          return isSnapshot( getVersion() );
      }
  
      private static boolean isSnapshot( String version )
      {
          return version.endsWith( SNAPSHOT ) || SNAPSHOT_TIMESTAMP.matcher( version ).matches();
      }
  
      public String getBaseVersion()
      {
          return toBaseVersion( getVersion() );
      }
  
      private static String toBaseVersion( String version )
      {
          String baseVersion;
  
          if ( version == null )
          {
              baseVersion = version;
          }
          else if ( version.startsWith( "[" ) || version.startsWith( "(" ) )
          {
              baseVersion = version;
          }
          else
          {
              Matcher m = SNAPSHOT_TIMESTAMP.matcher( version );
              if ( m.matches() )
              {
                  if ( m.group( 1 ) != null )
                  {
                      baseVersion = m.group( 1 ) + SNAPSHOT;
                  }
                  else
                  {
                      baseVersion = SNAPSHOT;
                  }
              }
              else
              {
                  baseVersion = version;
              }
          }
  
          return baseVersion;
      }
  
      /**
       * Creates a new artifact with the specified coordinates, properties and file.
       * 
       * @param version The version of the artifact, may be {@code null}.
       * @param properties The properties of the artifact, may be {@code null} if none. The method may assume immutability
       *            of the supplied map, i.e. need not copy it.
       * @param file The resolved file of the artifact, may be {@code null}.
       * @return The new artifact instance, never {@code null}.
       */
      private Artifact newInstance( String version, Map<String, String> properties, File file )
      {
          return new DefaultArtifact( getGroupId(), getArtifactId(), getClassifier(), getExtension(), version, file,
                                      properties );
      }
  
      public Artifact setVersion( String version )
      {
          String current = getVersion();
          if ( current.equals( version ) || ( version == null && current.length() <= 0 ) )
         {
             return this;
         }
         return newInstance( version, getProperties(), getFile() );
     }
 
     public Artifact setFile( File file )
     {
         File current = getFile();
         if ( ( current == null ) ? file == null : current.equals( file ) )
         {
             return this;
         }
         return newInstance( getVersion(), getProperties(), file );
     }
 
     public Artifact setProperties( Map<String, String> properties )
     {
         Map<String, String> current = getProperties();
         if ( current.equals( properties ) || ( properties == null && current.isEmpty() ) )
         {
             return this;
         }
         return newInstance( getVersion(), copyProperties( properties ), getFile() );
     }
 
     public String getProperty( String key, String defaultValue )
     {
         String value = getProperties().get( key );
         return ( value != null ) ? value : defaultValue;
     }
 
     /**
      * Copies the specified artifact properties. This utility method should be used when creating new artifact instances
      * with caller-supplied properties.
      * 
      * @param properties The properties to copy, may be {@code null}.
      * @return The copied and read-only properties, never {@code null}.
      */
     protected static Map<String, String> copyProperties( Map<String, String> properties )
     {
         if ( properties != null && !properties.isEmpty() )
         {
             return Collections.unmodifiableMap( new HashMap<String, String>( properties ) );
         }
         else
         {
             return Collections.emptyMap();
         }
     }
 
     @Override
     public String toString()
     {
         StringBuilder buffer = new StringBuilder( 128 );
         buffer.append( getGroupId() );
         buffer.append( ':' ).append( getArtifactId() );
         buffer.append( ':' ).append( getExtension() );
         if ( getClassifier().length() > 0 )
         {
             buffer.append( ':' ).append( getClassifier() );
         }
         buffer.append( ':' ).append( getVersion() );
         return buffer.toString();
     }
 
     /**
      * Compares this artifact with the specified object.
      * 
      * @param obj The object to compare this artifact against, may be {@code null}.
      * @return {@code true} if and only if the specified object is another {@link Artifact} with equal coordinates,
      *         properties and file, {@code false} otherwise.
      */
     @Override
     public boolean equals( Object obj )
     {
         if ( obj == this )
         {
             return true;
         }
         else if ( !( obj instanceof Artifact ) )
         {
             return false;
         }
 
         Artifact that = (Artifact) obj;
 
         return getArtifactId().equals( that.getArtifactId() ) && getGroupId().equals( that.getGroupId() )
             && getVersion().equals( that.getVersion() ) && getExtension().equals( that.getExtension() )
             && getClassifier().equals( that.getClassifier() ) && eq( getFile(), that.getFile() )
             && getProperties().equals( that.getProperties() );
     }
 
     private static <T> boolean eq( T s1, T s2 )
     {
         return s1 != null ? s1.equals( s2 ) : s2 == null;
     }
 
     /**
      * Returns a hash code for this artifact.
      * 
      * @return A hash code for the artifact.
      */
     @Override
     public int hashCode()
     {
         int hash = 17;
         hash = hash * 31 + getGroupId().hashCode();
         hash = hash * 31 + getArtifactId().hashCode();
         hash = hash * 31 + getExtension().hashCode();
         hash = hash * 31 + getClassifier().hashCode();
         hash = hash * 31 + getVersion().hashCode();
         hash = hash * 31 + hash( getFile() );
         return hash;
     }
 
     private static int hash( Object obj )
     {
         return ( obj != null ) ? obj.hashCode() : 0;
     }
 
 }