/**********************************************************************
Copyright (c) 2000, 2002 IBM Corp. and others.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Common Public License v1.0
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/cpl-v10.html

Contributors:
    IBM Corporation - Initial implementation
    Klaus Hartlage - www.eclipseproject.de
**********************************************************************/
package net.sourceforge.phpeclipse.phpeditor.php;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.SortedMap;

import net.sourceforge.phpdt.core.ToolFactory;
import net.sourceforge.phpdt.core.compiler.ITerminalSymbols;
import net.sourceforge.phpdt.core.compiler.InvalidInputException;
import net.sourceforge.phpdt.internal.compiler.parser.Scanner;
import net.sourceforge.phpdt.internal.corext.template.ContextType;
import net.sourceforge.phpdt.internal.corext.template.ContextTypeRegistry;
import net.sourceforge.phpdt.internal.corext.template.php.CompilationUnitContextType;
import net.sourceforge.phpdt.internal.corext.template.php.PHPUnitContext;
import net.sourceforge.phpdt.internal.ui.text.java.IPHPCompletionProposal;
import net.sourceforge.phpdt.internal.ui.text.java.PHPCompletionProposalComparator;
import net.sourceforge.phpdt.internal.ui.text.template.BuiltInEngine;
import net.sourceforge.phpdt.internal.ui.text.template.DeclarationEngine;
import net.sourceforge.phpdt.internal.ui.text.template.IdentifierEngine;
import net.sourceforge.phpdt.internal.ui.text.template.TemplateEngine;
import net.sourceforge.phpeclipse.PHPeclipsePlugin;
import net.sourceforge.phpeclipse.builder.IdentifierIndexManager;
import net.sourceforge.phpeclipse.phpeditor.AbstractContentOutlinePage;
import net.sourceforge.phpeclipse.phpeditor.PHPContentOutlinePage;
import net.sourceforge.phpeclipse.phpeditor.PHPEditor;
import net.sourceforge.phpeclipse.phpeditor.PHPSyntaxRdr;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
import org.eclipse.jface.text.contentassist.IContextInformation;
import org.eclipse.jface.text.contentassist.IContextInformationExtension;
import org.eclipse.jface.text.contentassist.IContextInformationPresenter;
import org.eclipse.jface.text.contentassist.IContextInformationValidator;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IFileEditorInput;

/**
 * Example PHP completion processor.
 */
public class PHPCompletionProcessor implements IContentAssistProcessor {

  /**
   * Simple content assist tip closer. The tip is valid in a range
   * of 5 characters around its popup location.
   */
  protected static class Validator implements IContextInformationValidator, IContextInformationPresenter {

    protected int fInstallOffset;

    /*
     * @see IContextInformationValidator#isContextInformationValid(int)
     */
    public boolean isContextInformationValid(int offset) {
      return Math.abs(fInstallOffset - offset) < 5;
    }

    /*
     * @see IContextInformationValidator#install(IContextInformation, ITextViewer, int)
     */
    public void install(IContextInformation info, ITextViewer viewer, int offset) {
      fInstallOffset = offset;
    }

    /*
     * @see org.eclipse.jface.text.contentassist.IContextInformationPresenter#updatePresentation(int, TextPresentation)
     */
    public boolean updatePresentation(int documentPosition, TextPresentation presentation) {
      return false;
    }
  };

  private static class ContextInformationWrapper implements IContextInformation, IContextInformationExtension {

    private final IContextInformation fContextInformation;
    private int fPosition;

    public ContextInformationWrapper(IContextInformation contextInformation) {
      fContextInformation = contextInformation;
    }

    /*
     * @see IContextInformation#getContextDisplayString()
     */
    public String getContextDisplayString() {
      return fContextInformation.getContextDisplayString();
    }

    /*
    * @see IContextInformation#getImage()
    */
    public Image getImage() {
      return fContextInformation.getImage();
    }

    /*
     * @see IContextInformation#getInformationDisplayString()
     */
    public String getInformationDisplayString() {
      return fContextInformation.getInformationDisplayString();
    }

    /*
     * @see IContextInformationExtension#getContextInformationPosition()
     */
    public int getContextInformationPosition() {
      return fPosition;
    }

    public void setContextInformationPosition(int position) {
      fPosition = position;
    }
  };

  private char[] fProposalAutoActivationSet;
  protected IContextInformationValidator fValidator = new Validator();
  private TemplateEngine fTemplateEngine;
  private PHPCompletionProposalComparator fComparator;
  private int fNumberOfComputedResults = 0;

  public PHPCompletionProcessor() {

    ContextType contextType = ContextTypeRegistry.getInstance().getContextType("php"); //$NON-NLS-1$
    if (contextType != null)
      fTemplateEngine = new TemplateEngine(contextType);

    fComparator = new PHPCompletionProposalComparator();
  }

  /**
   * Tells this processor to order the proposals alphabetically.
   * 
   * @param order <code>true</code> if proposals should be ordered.
   */
  public void orderProposalsAlphabetically(boolean order) {
    fComparator.setOrderAlphabetically(order);
  }

  /**
   * Sets this processor's set of characters triggering the activation of the
   * completion proposal computation.
   * 
   * @param activationSet the activation set
   */
  public void setCompletionProposalAutoActivationCharacters(char[] activationSet) {
    fProposalAutoActivationSet = activationSet;
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int documentOffset) {
    int contextInformationPosition = guessContextInformationPosition(viewer, documentOffset);
    return internalComputeCompletionProposals(viewer, documentOffset, contextInformationPosition);
  }

  private int getLastToken(ITextViewer viewer, int completionPosition, PHPUnitContext context) {
    IDocument document = viewer.getDocument();
    int start = context.getStart();
    int end = context.getEnd();

    String startText;
    int lastSignificantToken = ITerminalSymbols.TokenNameEOF;

    try {
      // begin search 2 lines behind of this
      int j = start;
      if (j != 0) {
        char ch;
        while (j-- > 0) {
          ch = document.getChar(j);
          if (ch == '\n') {
            break;
          }
        }
        while (j-- > 0) {
          ch = document.getChar(j);
          if (ch == '\n') {
            break;
          }
        }
      }
      if (j != start) {
        // scan the line for the dereferencing operator '->'
        startText = document.get(j, start - j);
        //						System.out.println(startText);
        Scanner scanner = ToolFactory.createScanner(false, false, false);
        scanner.setSource(startText.toCharArray());
        scanner.setPHPMode(true);
        int token = ITerminalSymbols.TokenNameEOF;
        int beforeLastToken = ITerminalSymbols.TokenNameEOF;
        int lastToken = ITerminalSymbols.TokenNameEOF;

        try {
          token = scanner.getNextToken();
          lastToken = token;
          while (token != ITerminalSymbols.TokenNameERROR && token != ITerminalSymbols.TokenNameEOF) {
            beforeLastToken = lastToken;
            lastToken = token;
            //								System.out.println(scanner.toStringAction(lastToken));
            token = scanner.getNextToken();
          }
        } catch (InvalidInputException e1) {
        }
        switch (lastToken) {
          case ITerminalSymbols.TokenNameMINUS_GREATER :
            // dereferencing operator '->' found
            lastSignificantToken = ITerminalSymbols.TokenNameMINUS_GREATER;
            if (beforeLastToken == ITerminalSymbols.TokenNamethis) {
              lastSignificantToken = ITerminalSymbols.TokenNamethis;
            }
            break;
          case ITerminalSymbols.TokenNamenew :
            lastSignificantToken = ITerminalSymbols.TokenNamenew;
            break;
        }
      }
    } catch (BadLocationException e) {
    }
    return lastSignificantToken;
  }

  private ICompletionProposal[] internalComputeCompletionProposals(ITextViewer viewer, int offset, int contextOffset) {
    IDocument document = viewer.getDocument();
    Object[] identifiers = null;
    IFile file = null;
    IProject project = null;
    if (offset > 0) {

      PHPEditor editor = null;
      AbstractContentOutlinePage outlinePage = null;

      IEditorPart targetEditor = PHPeclipsePlugin.getActiveWorkbenchWindow().getActivePage().getActiveEditor();
      if (targetEditor != null && (targetEditor instanceof PHPEditor)) {
        editor = (PHPEditor) targetEditor;
        file = ((IFileEditorInput) editor.getEditorInput()).getFile();
        project = file.getProject();
        outlinePage = editor.getfOutlinePage();
        if (outlinePage instanceof PHPContentOutlinePage) {
          identifiers = ((PHPContentOutlinePage) outlinePage).getVariables();
        }
      }
    }

    ContextType phpContextType = ContextTypeRegistry.getInstance().getContextType("php"); //$NON-NLS-1$
     ((CompilationUnitContextType) phpContextType).setContextParameters(document, offset, 0);

    PHPUnitContext context = (PHPUnitContext) phpContextType.createContext();
    String prefix = context.getKey();

    int lastSignificantToken = getLastToken(viewer, offset, context);
    boolean useClassMembers =
      (lastSignificantToken == ITerminalSymbols.TokenNameMINUS_GREATER) || 
      (lastSignificantToken == ITerminalSymbols.TokenNamethis) ||
		  (lastSignificantToken == ITerminalSymbols.TokenNamenew);
    boolean emptyPrefix = prefix == null || prefix.equals("");

    if (fTemplateEngine != null) {
      IPHPCompletionProposal[] templateResults = new IPHPCompletionProposal[0];

      ICompletionProposal[] results;
      if (!emptyPrefix) {
        fTemplateEngine.reset();
        fTemplateEngine.complete(viewer, offset); //, unit);
        templateResults = fTemplateEngine.getResults();
      }

      IPHPCompletionProposal[] identifierResults = new IPHPCompletionProposal[0];
      if ((!useClassMembers) && identifiers != null) {
        IdentifierEngine identifierEngine;

        ContextType contextType = ContextTypeRegistry.getInstance().getContextType("php"); //$NON-NLS-1$
        if (contextType != null) {
          identifierEngine = new IdentifierEngine(contextType);
          identifierEngine.complete(viewer, offset, identifiers);
          identifierResults = identifierEngine.getResults();
        }
      }

      // declarations stored in file project.index on project level
      IPHPCompletionProposal[] declarationResults = new IPHPCompletionProposal[0];
      if (project != null) {
        DeclarationEngine declarationEngine;

        ContextType contextType = ContextTypeRegistry.getInstance().getContextType("php"); //$NON-NLS-1$
        if (contextType != null) {
          IdentifierIndexManager indexManager = PHPeclipsePlugin.getDefault().getIndexManager(project);
          SortedMap sortedMap = indexManager.getIdentifierMap();

          declarationEngine = new DeclarationEngine(contextType, lastSignificantToken, file);
          declarationEngine.complete(viewer, offset, sortedMap);
          declarationResults = declarationEngine.getResults();
        }
      }

      // built in function names from phpsyntax.xml
      ArrayList syntaxbuffer = PHPSyntaxRdr.getSyntaxData();
      IPHPCompletionProposal[] builtinResults = new IPHPCompletionProposal[0];
      if ((!useClassMembers) && syntaxbuffer != null) {
        BuiltInEngine builtinEngine;
        String proposal;

        ContextType contextType = ContextTypeRegistry.getInstance().getContextType("php"); //$NON-NLS-1$
        if (contextType != null) {
          builtinEngine = new BuiltInEngine(contextType);
          builtinEngine.complete(viewer, offset, syntaxbuffer);
          builtinResults = builtinEngine.getResults();
        }
      }

      // concatenate the result arrays
      IPHPCompletionProposal[] total;
      total =
        new IPHPCompletionProposal[templateResults.length
          + identifierResults.length
          + builtinResults.length
          + declarationResults.length];
      System.arraycopy(templateResults, 0, total, 0, templateResults.length);
      System.arraycopy(identifierResults, 0, total, templateResults.length, identifierResults.length);
      System.arraycopy(builtinResults, 0, total, templateResults.length + identifierResults.length, builtinResults.length);
      System.arraycopy(
        declarationResults,
        0,
        total,
        templateResults.length + identifierResults.length + builtinResults.length,
        declarationResults.length);

      results = total;

      fNumberOfComputedResults = (results == null ? 0 : results.length);
      /*
       * Order here and not in result collector to make sure that the order
       * applies to all proposals and not just those of the compilation unit. 
       */
      return order(results);
    }
    return new IPHPCompletionProposal[0];
  }

  private int guessContextInformationPosition(ITextViewer viewer, int offset) {
    int contextPosition = offset;

    IDocument document = viewer.getDocument();

    //    try {
    //
    //      PHPCodeReader reader= new PHPCodeReader();
    //      reader.configureBackwardReader(document, offset, true, true);
    //  
    //      int nestingLevel= 0;
    //
    //      int curr= reader.read();    
    //      while (curr != PHPCodeReader.EOF) {
    //
    //        if (')' == (char) curr)
    //          ++ nestingLevel;
    //
    //        else if ('(' == (char) curr) {
    //          -- nestingLevel;
    //        
    //          if (nestingLevel < 0) {
    //            int start= reader.getOffset();
    //            if (looksLikeMethod(reader))
    //              return start + 1;
    //          } 
    //        }
    //
    //        curr= reader.read();          
    //      }
    //    } catch (IOException e) {
    //    }

    return contextPosition;
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  //  public IContextInformation[] computeContextInformation(ITextViewer viewer, int documentOffset) {
  //    IContextInformation[] result = new IContextInformation[5];
  //    for (int i = 0; i < result.length; i++)
  //      result[i] = new ContextInformation(MessageFormat.format(PHPEditorMessages.getString("CompletionProcessor.ContextInfo.display.pattern"), new Object[] { new Integer(i), new Integer(documentOffset)}), //$NON-NLS-1$
  //      MessageFormat.format(PHPEditorMessages.getString("CompletionProcessor.ContextInfo.value.pattern"), new Object[] { new Integer(i), new Integer(documentOffset - 5), new Integer(documentOffset + 5)})); //$NON-NLS-1$
  //    return result;
  //  }
  /**
   * @see IContentAssistProcessor#computeContextInformation(ITextViewer, int)
   */
  public IContextInformation[] computeContextInformation(ITextViewer viewer, int offset) {
    int contextInformationPosition = guessContextInformationPosition(viewer, offset);
    List result = addContextInformations(viewer, contextInformationPosition);
    return (IContextInformation[]) result.toArray(new IContextInformation[result.size()]);
  }

  private List addContextInformations(ITextViewer viewer, int offset) {
    ICompletionProposal[] proposals = internalComputeCompletionProposals(viewer, offset, -1);

    List result = new ArrayList();
    for (int i = 0; i < proposals.length; i++) {
      IContextInformation contextInformation = proposals[i].getContextInformation();
      if (contextInformation != null) {
        ContextInformationWrapper wrapper = new ContextInformationWrapper(contextInformation);
        wrapper.setContextInformationPosition(offset);
        result.add(wrapper);
      }
    }
    return result;
  }

  /**
   * Order the given proposals.
   */
  private ICompletionProposal[] order(ICompletionProposal[] proposals) {
    Arrays.sort(proposals, fComparator);
    return proposals;
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  public char[] getCompletionProposalAutoActivationCharacters() {
    return fProposalAutoActivationSet;
    //    return null; // new char[] { '$' };
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  public char[] getContextInformationAutoActivationCharacters() {
    return new char[] {
    };
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  public IContextInformationValidator getContextInformationValidator() {
    return fValidator;
  }

  /* (non-Javadoc)
   * Method declared on IContentAssistProcessor
   */
  public String getErrorMessage() {
    return null;
  }
}