/**
    * 
    */
   package org.kuali.student.git.model;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.List;
   
  import org.kuali.student.svn.model.ExternalModuleInfo;
  
  /**
   * @author Kuali Student Team
   *
   */
  public class ExternalsUtils {
  
  	/**
  	 * 
  	 */
  	public ExternalsUtils() {
  		// TODO Auto-generated constructor stub
  	}
  
  	private static int indexOf (List<GitBranchData>list, String targetBranchPath) {
  		for (int i = 0; i < list.size(); i++) {
  
  			GitBranchData data = list.get(i);
  			
  			if (data.getBranchPath().equals(targetBranchPath))
  				return i;
  		}
  		
  		return -1;
  	}
  	
  	
  	/**
  	 * Reorder the unordered list so that branches that have externals dependencies will be placed after them in the list.
  	 * 
  	 * This is needed so that when we write the externals data they refer to the latest commit id's in the external branches.
  	 * 
  	 * @param unorderedList
  	 * @return
  	 */
  	public static List<GitBranchData> computeExternalsAwareOrdering(Collection<GitBranchData>unorderedList) {
  		
  		List<GitBranchData> results = new ArrayList<> (unorderedList.size());
  		
  		results.addAll(unorderedList);
  		
  		if (results.size() == 1)
  			return results;
  		
  		for (GitBranchData data : unorderedList) {
  			
  			List<ExternalModuleInfo> externals = data.getExternals();
  			
  			if (externals.size() > 0) {
  				
  				for (ExternalModuleInfo external : externals) {
  					
  					int indexOfDependentBranch = indexOf(results, data.getBranchPath());						
  					
  					int indexOfCurrentExternal = indexOf (results, external.getBranchPath());
  					
  					if (indexOfDependentBranch == -1 || indexOfCurrentExternal == -1)
  						continue; // skip over any case where the external isn't represented in the current branches to be committed.
  					
  					if (indexOfDependentBranch < indexOfCurrentExternal) {
  						// remove the dependent branch and insert it after the current external.
  						
  						if ((indexOfCurrentExternal + 1) == results.size()) {
  							// adding at the end of the list
  							GitBranchData obj = results.remove(indexOfDependentBranch);
  							
  							results.add(obj);
  						}
  						else {
  							
  							/*
  							 * Add after the external.
  							 */
  							GitBranchData obj = results.get(indexOfDependentBranch);
  							
  							results.add(indexOfCurrentExternal+1, obj);
  							
  							// remove after the add so as to not mess up the indexing.
  							results.remove(indexOfDependentBranch);
  						}
  					}
  				}
  			}
  			
  		}
  		
  		
  		return results;
  	}
 }