/*******************************************************************************
 * Copyright (c) 2008 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
 *******************************************************************************/

package org.maven.ide.eclipse.internal.project;

import java.util.Enumeration;
import java.util.List;
import java.util.Properties;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.IPath;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
import org.apache.maven.artifact.resolver.ArtifactResolutionException;
import org.apache.maven.artifact.resolver.DefaultArtifactResolver;
import org.apache.maven.embedder.MavenEmbedder;
import org.apache.maven.settings.Profile;
import org.apache.maven.settings.Settings;

import org.maven.ide.eclipse.MavenPlugin;
import org.maven.ide.eclipse.embedder.ArtifactKey;


/**
 * The <code>MyEclipseArtifactResolver</code> is basically a copy of 
 * <code>EclipseArtifactResolver</code> with the addition of handling 
 * reading properties from the active profiles available and substituting
 * those variables, if there is a match. 
 * <p>The other class affected by the scheme implemented here is:
 * <code>MavenProjectManagerImpl</code>, whose line 1137 is altered
 * to instantiate this class instead of the copied resolver. </p> 
 * 
 * @author original author unascribed
 * @author rova
 */
public class MyEclipseArtifactResolver extends DefaultArtifactResolver {
  
  public void resolve(Artifact artifact, List<ArtifactRepository> remoteRepositories, ArtifactRepository localRepository) throws ArtifactResolutionException, ArtifactNotFoundException {
    
    artifact = this.checkArtifact4Variables(artifact);
    
    if(!resolveAsEclipseProject(artifact)) {

      super.resolve(artifact, remoteRepositories, localRepository);
    }
  }

  public void resolveAlways(Artifact artifact, List<ArtifactRepository> remoteRepositories, ArtifactRepository localRepository) throws ArtifactResolutionException, ArtifactNotFoundException {
    
    artifact = this.checkArtifact4Variables(artifact);
    
    if(!resolveAsEclipseProject( artifact ) ) {
      
      super.resolveAlways(artifact, remoteRepositories, localRepository);
    }
  }

  protected static boolean resolveAsEclipseProject(Artifact artifact) {
    
    MavenProjectManagerImpl.Context context = MavenProjectManagerImpl.getContext();
    if(context == null) { // XXX this is actually a bug 
      return false;
    }

    if(artifact == null) {
      // according to the DefaultArtifactResolver source code, it looks like artifact can be null
      return false;
    }

    // check in the workspace, note that workspace artifacts never have classifiers
    ArtifactKey key = new ArtifactKey(artifact.getGroupId(), artifact.getArtifactId(), artifact.getBaseVersion(), null);
    
    IPath pomPath = context.state.getWorkspaceArtifact(key);
    
    if( pomPath == null ) {
      return false;
    }

    IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
    IFile pom = root.getFile(pomPath);
    
    if( pom == null || !pom.isAccessible() ) {
      
      // XXX this is really a bug, need to throw something meaningful
      return false;
    }

    if( context.resolverConfiguration.shouldResolveWorkspaceProjects() || 
      ( context.resolverConfiguration.shouldIncludeModules()           && 
        WorkspaceState.isSameProject( context.pom, pom ) )             ){

      IPath file = pom.getLocation();
      
      if( !"pom".equals( artifact.getType() ) ) {
        
        MavenProjectFacade facade = context.state.getProjectFacade( pom );
        IFolder outputLocation = root.getFolder( facade.getOutputLocation() );
        
        if(outputLocation.exists()) {
          file = outputLocation.getLocation();
        }
      }

      artifact.setFile( file.toFile() );
      artifact.setResolved( true );

      return true;
    }

    return false;
  }
  
  /**
   * Check whether an artifact holds potential variables for replacement
   * from an active profile. if there no such variables, the artifact is
   * left intact. 
   * 
   * @param artifact artifact to check 
   * @return checked artifact, possible variables substituted
   */
  @SuppressWarnings("unchecked")
  private Artifact checkArtifact4Variables( Artifact artifact ){

    ArtifactKey key = new ArtifactKey(artifact.getGroupId(), artifact.getArtifactId(), artifact.getBaseVersion(), null);
    
    if( key.toString().indexOf('$') >= 0 ) {
      
      // Unresolved property, for example ${parentversion}
      // Find out which property of the artifact key which
      // is to be substituted with a variable value...
      
      String groupId = key.getGroupId();
      String artifactId = key.getArtifactId();
      String version = key.getVersion();
      
      MavenPlugin plugin = MavenPlugin.getDefault();
      
      try{
      
        MavenEmbedder embedder = plugin.getMavenEmbedderManager().getWorkspaceEmbedder();
        
        Settings s = embedder.getSettings();
        
        List<String> actProfiles = s.getActiveProfiles();
        
        // TODO: If there are no active profiles, we can skip the rest ... 
        List<Profile> profiles = s.getProfiles();
        
        for(Object profile : profiles) {
          
          Profile p = ( Profile ) profile;
          
          for(Object actProfile : actProfiles) {
            
            String id = ( String ) actProfile;
            
            if( p.getId().equals( id ) ){
              
              // This profile is active ... 
              Properties props = p.getProperties();
              
              for( Enumeration e = props.keys(); e.hasMoreElements() ;){
                
                String propKey = ( String ) e.nextElement();
                
                if( groupId.indexOf('$') >= 0  ){
                  
                  // groupId potential variable
                  if( strip( groupId ).equals( propKey ) ){
                    
                    groupId = props.getProperty( propKey );
                    artifact.setGroupId( groupId );
                  }
                  
                }else if( artifactId.indexOf('$') >= 0 ){
                  
                  // artifactId potential variable
                  if( strip( artifactId ).equals( propKey ) ){
                    
                    artifactId = props.getProperty( propKey );
                    artifact.setArtifactId( artifactId );
                  }
                  
                }else if( version.indexOf('$') >= 0 ) {
                  
                  // version potential variable
                  if( strip( version ).equals( propKey ) ){
                    
                    version = props.getProperty( propKey );
                    artifact.setVersion( version );
                  }
                }
              }
            }
          }
        }
        
      }catch (Exception ex) {
        // TODO: handle exception
      }
    }
    
    return artifact;
  }
  
  /**
   * If a string is a potential variable for substitution, strip away 
   * the variable admin. stuff.
   * <p>Please keep in mind that there is no check whether this is a 
   * potential variable or not. It assumed that this check is done 
   * prior to calling this method. </p> 
   * 
   * @param entity potential variable
   * @return stripped from variable enclosing brackets etc. 
   */
  private String strip( String entity ){
    
    String s = entity.substring( 2 ); // Skip the '${
    
    return s.substring( 0, ( s.length() - 1 ) ); // Strip away the trailing '}'
  }
}