/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2003-2005, University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs;

import java.io.IOException;
import java.util.BitSet;
import java.util.Iterator;

import javax.annotation.CheckForNull;

import org.apache.bcel.classfile.LineNumberTable;
import org.apache.bcel.classfile.LocalVariable;
import org.apache.bcel.classfile.LocalVariableTable;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.IndexedInstruction;
import org.apache.bcel.generic.InstructionHandle;

import edu.umd.cs.findbugs.OpcodeStack.Item;
import edu.umd.cs.findbugs.ba.AnalysisContext;
import edu.umd.cs.findbugs.ba.CFG;
import edu.umd.cs.findbugs.ba.CFGBuilderException;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.Dataflow;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.LiveLocalStoreAnalysis;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.SignatureParser;
import edu.umd.cs.findbugs.util.EditDistance;
import edu.umd.cs.findbugs.visitclass.DismantleBytecode;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;
import edu.umd.cs.findbugs.xml.XMLAttributeList;
import edu.umd.cs.findbugs.xml.XMLOutput;

/**
 * Bug annotation class for local variable names
 *
 * @author William Pugh
 * @see BugAnnotation
 */
public class LocalVariableAnnotation implements BugAnnotation {
	private static final long serialVersionUID = 1L;

	public static final String DEFAULT_ROLE="LOCAL_VARIABLE_DEFAULT";
	public static final String NAMED_ROLE="LOCAL_VARIABLE_NAMED";
	public static final String UNKNOWN_ROLE="LOCAL_VARIABLE_UNKNOWN";
	public static final String PARAMETER_ROLE="LOCAL_VARIABLE_PARAMETER";
	public static final String PARAMETER_NAMED_ROLE="LOCAL_VARIABLE_PARAMETER_NAMED";
	public static final String PARAMETER_VALUE_SOURCE_ROLE="LOCAL_VARIABLE_PARAMETER_VALUE_SOURCE"; 
	public static final String PARAMETER_VALUE_SOURCE_NAMED_ROLE="LOCAL_VARIABLE_PARAMETER_VALUE_SOURCE_NAMED";
	public static final String VALUE_DOOMED_ROLE="LOCAL_VARIABLE_VALUE_DOOMED";
	public static final String VALUE_DOOMED_NAMED_ROLE="LOCAL_VARIABLE_VALUE_DOOMED_NAMED";
	public static final String DID_YOU_MEAN_ROLE="LOCAL_VARIABLE_DID_YOU_MEAN";
	public static final String INVOKED_ON_ROLE="LOCAL_VARIABLE_INVOKED_ON";
	public static final String ARGUMENT_ROLE="LOCAL_VARIABLE_ARGUMENT";
	public static final String VALUE_OF_ROLE="LOCAL_VARIABLE_VALUE_OF";



	final private String value;
	final int register, pc;
	final int line;
	 private String description;

	/**
	 * Constructor.
	 *
	 * @param name     the name of the local variable
	 * @param register the local variable index
	 * @param pc       the bytecode offset of the instruction that mentions
	 *                 this local variable
	 */
	public LocalVariableAnnotation(String name, int register, int pc) {
		this.value = name;
		this.register = register;
		this.pc = pc;
		this.line = -1;
		this.description = DEFAULT_ROLE;
		this.setDescription(name.equals("?") ? "LOCAL_VARIABLE_UNKNOWN" : "LOCAL_VARIABLE_NAMED");
	}
	/**
	 * Constructor.
	 *
	 * @param name     the name of the local variable
	 * @param register the local variable index
	 * @param pc       the bytecode offset of the instruction that mentions
	 *                 this local variable
	 */
	public LocalVariableAnnotation(String name, int register, int pc, int line) {
		this.value = name;
		this.register = register;
		this.pc = pc;
		this.line = line;
		this.description = DEFAULT_ROLE;
		this.setDescription(name.equals("?") ? "LOCAL_VARIABLE_UNKNOWN" : "LOCAL_VARIABLE_NAMED");
	}

	public static LocalVariableAnnotation getLocalVariableAnnotation(
			Method method, Location location, IndexedInstruction ins) {
		int local = ins.getIndex();
		InstructionHandle handle = location.getHandle();
		int position1 = handle.getNext().getPosition();
		int position2 = handle.getPosition();
		return getLocalVariableAnnotation(method, local, position1, position2);
	}

	public static LocalVariableAnnotation getLocalVariableAnnotation(
			Method method, int local, int position1, int position2) {

		LocalVariableTable localVariableTable = method.getLocalVariableTable();
		String localName = "?";
		if (localVariableTable != null) {
			LocalVariable lv1 = localVariableTable.getLocalVariable(local, position1);
			if (lv1 == null) {
				lv1 = localVariableTable.getLocalVariable(local, position2);
				position1 = position2;
			}
			if (lv1 != null) 
				localName = lv1.getName();
			else
				for (LocalVariable lv : localVariableTable.getLocalVariableTable()) {
					if (lv.getIndex() == local) {
						if (!localName.equals("?") && !localName.equals(lv.getName())) {
							// not a single consistent name
							localName = "?";
							break;
						}
						localName = lv.getName();
					}
			}
		}
		LineNumberTable lineNumbers = method.getLineNumberTable();
		if (lineNumbers == null)
			 return new LocalVariableAnnotation(localName, local, position1);
		int line = lineNumbers.getSourceLine(position1);
		return new LocalVariableAnnotation(localName, local, position1, line);
	}

	/**
	 * Get a local variable annotation describing a parameter.
	 * 
	 * @param method a Method
	 * @param local  the local variable containing the parameter
	 * @return LocalVariableAnnotation describing the parameter
	 */
	public static LocalVariableAnnotation getParameterLocalVariableAnnotation(Method method, int local) {
		LocalVariableAnnotation lva = getLocalVariableAnnotation(method, local, 0, 0);
		return lva;
	}

	@Override
	public Object clone() {
		try {
			return super.clone();
		} catch (CloneNotSupportedException e) {
			throw new AssertionError(e);
		}
	}


	public void accept(BugAnnotationVisitor visitor) {
		visitor.visitLocalVariableAnnotation(this);
	}

	public String format(String key, ClassAnnotation primaryClass) {
		// System.out.println("format: " + key + " reg: " + register + " name: " + value);
		if (key.equals("hash")) {
			if (register < 0) return "??";
			return value;
		}
		if (register < 0) return "?";
		if (key.equals("register")) return String.valueOf(register);
		else if (key.equals("pc")) return String.valueOf(pc);
		else if (key.equals("name") || key.equals("givenClass")) return value;
		else if (!value.equals("?")) return value;
		return "$L"+register;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	public String getDescription() {
		return description;
	}

	@Override
	public int hashCode() {
		return value.hashCode();
	}

	@Override
	public boolean equals(Object o) {
		if (!(o instanceof LocalVariableAnnotation))
			return false;
		return value.equals(((LocalVariableAnnotation) o).value);
	}

	public int compareTo(BugAnnotation o) {
		if (!(o instanceof LocalVariableAnnotation)) // BugAnnotations must be Comparable with any type of BugAnnotation
			return this.getClass().getName().compareTo(o.getClass().getName());
		return value.compareTo(((LocalVariableAnnotation) o).value);
	}

	@Override
	public String toString() {
		String pattern = I18N.instance().getAnnotationDescription(description);
		FindBugsMessageFormat format = new FindBugsMessageFormat(pattern);
		return format.format(new BugAnnotation[]{this}, null);
	}

	/* ----------------------------------------------------------------------
	 * XML Conversion support
	 * ---------------------------------------------------------------------- */

	private static final String ELEMENT_NAME = "LocalVariable";

	public void writeXML(XMLOutput xmlOutput) throws IOException {
		writeXML(xmlOutput, false, false);
	}

	public void writeXML(XMLOutput xmlOutput, boolean addMessages, boolean isPrimary) throws IOException {
		XMLAttributeList attributeList = new XMLAttributeList()
			.addAttribute("name", value)
		.addAttribute("register", String.valueOf(register))
		.addAttribute("pc", String.valueOf(pc));

		String role = getDescription();
		if (!role.equals(DEFAULT_ROLE))
			attributeList.addAttribute("role", role);

		BugAnnotationUtil.writeXML(xmlOutput, ELEMENT_NAME, this, attributeList, addMessages);
	}

	public boolean isNamed() {
		return register >= 0 && !value.equals("?");
	}
	/**
	 * @return name of local variable
	 */
	public String getName() {
		return value;
	}

	public int getPC() {
		return pc;
	}
	public int getRegister() {
		return register;
	}

	public boolean isSignificant() {
		return !value.equals("?");
	}

	/**
     * @param method
     * @param item
     * @param pc2
     * @return
     */
    public static @CheckForNull LocalVariableAnnotation getLocalVariableAnnotation(Method method, Item item, int pc) {
	   int reg = item.getRegisterNumber();
	   if (reg < 0) return null;
	   return getLocalVariableAnnotation(method, reg, pc, item.getPC());
	   
    }
    public static @CheckForNull LocalVariableAnnotation getLocalVariableAnnotation(DismantleBytecode visitor, Item item) {
 	   int reg = item.getRegisterNumber();
 	   if (reg < 0) return null;
 	   return getLocalVariableAnnotation(visitor.getMethod(), reg, visitor.getPC(), item.getPC());
 	   
     }
    
	public static @CheckForNull
	LocalVariableAnnotation findMatchingIgnoredParameter(ClassContext classContext, Method method, String name, String signature) {
		try {
			Dataflow<BitSet, LiveLocalStoreAnalysis> llsaDataflow = classContext.getLiveLocalStoreDataflow(method);
			CFG cfg;

			cfg = classContext.getCFG(method);
			LocalVariableAnnotation match = null;
			int lowestCost = Integer.MAX_VALUE;
			BitSet liveStoreSetAtEntry = llsaDataflow.getAnalysis().getResultFact(cfg.getEntry());
			int localsThatAreParameters = PreorderVisitor.getNumberArguments(method.getSignature());
			int startIndex = 0;
			if (!method.isStatic())
				startIndex = 1;
			SignatureParser parser = new SignatureParser(method.getSignature());
			Iterator<String> signatureIterator = parser.parameterSignatureIterator();
			for(int i = startIndex; i < localsThatAreParameters+startIndex; i++) {
				String sig = signatureIterator.next();
				if (!liveStoreSetAtEntry.get(i) && signature.equals(sig)) {
					// parameter isn't live and signatures match
					LocalVariableAnnotation potentialMatch = LocalVariableAnnotation.getLocalVariableAnnotation(method, i, 0, 0);
					potentialMatch.setDescription(DID_YOU_MEAN_ROLE);
					if (!potentialMatch.isNamed()) 
						return potentialMatch;
					int distance = EditDistance.editDistance(name, potentialMatch.getName());
					if (distance < lowestCost) {
						match = potentialMatch;
						match.setDescription(DID_YOU_MEAN_ROLE);
						lowestCost = distance;
					} else if (distance == lowestCost) {
						// not unique best match
						match = null;
					}
	
					
				}
			}
			return match;
		} catch (DataflowAnalysisException e) {
			AnalysisContext.logError("", e);
		} catch (CFGBuilderException e) {
			AnalysisContext.logError("", e);
		}
		return null;
	}
	public static @CheckForNull
	LocalVariableAnnotation findUniqueBestMatchingParameter(ClassContext classContext, Method method, String name, String signature) {
		LocalVariableAnnotation match = null;
		int localsThatAreParameters = PreorderVisitor.getNumberArguments(method.getSignature());
		int startIndex = 0;
		if (!method.isStatic())
			startIndex = 1;
		SignatureParser parser = new SignatureParser(method.getSignature());
		Iterator<String> signatureIterator = parser.parameterSignatureIterator();
		int lowestCost = Integer.MAX_VALUE;
		for(int i = startIndex; i < localsThatAreParameters+startIndex; i++) {
			String sig = signatureIterator.next();
			if (signature.equals(sig)) {
				LocalVariableAnnotation potentialMatch = LocalVariableAnnotation.getLocalVariableAnnotation(method, i, 0, 0);
				if (!potentialMatch.isNamed()) 
					continue;
				int distance = EditDistance.editDistance(name, potentialMatch.getName());
				if (distance < lowestCost) {
					match = potentialMatch;
					match.setDescription(DID_YOU_MEAN_ROLE);
					lowestCost = distance;
				} else if (distance == lowestCost) {
					// not unique best match
					match = null;
				}
				// signatures match
			}
		}
		if (lowestCost < 5)
			return match;
		return null;
	}
}

// vim:ts=4
