/*
 * Copyright (C) 2009-2018 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package lombok.javac;

import static lombok.javac.JavacAugments.JCTree_handled;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;

import javax.annotation.processing.Messager;
import javax.tools.Diagnostic;

import lombok.core.AlreadyHandledAnnotations;
import lombok.core.AnnotationValues.AnnotationValueDecodeFail;
import lombok.core.HandlerPriority;
import lombok.core.SpiLoadUtil;
import lombok.core.TypeLibrary;
import lombok.core.TypeResolver;
import lombok.core.configuration.ConfigurationKeysLoader;
import lombok.javac.handlers.JavacHandlerUtil;

import com.sun.source.util.Trees;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;

This class tracks 'handlers' and knows how to invoke them for any given AST node.
This class can find the handlers (via SPI discovery) and will set up the given AST node, such as
building an AnnotationValues instance.
/**
 * This class tracks 'handlers' and knows how to invoke them for any given AST node.
 * 
 * This class can find the handlers (via SPI discovery) and will set up the given AST node, such as
 * building an AnnotationValues instance.
 */
public class HandlerLibrary {
	private final TypeLibrary typeLibrary = new TypeLibrary();
	private final Map<String, List<AnnotationHandlerContainer<?>>> annotationHandlers = new HashMap<String, List<AnnotationHandlerContainer<?>>>();
	private final Collection<VisitorContainer> visitorHandlers = new ArrayList<VisitorContainer>();
	private final Messager messager;
	
	
Creates a new HandlerLibrary that will report any problems or errors to the provided messager. You probably want to use load(Messager) instead. /**
	 * Creates a new HandlerLibrary that will report any problems or errors to the provided messager.
	 * You probably want to use {@link #load(Messager)} instead.
	 */
	public HandlerLibrary(Messager messager) {
		ConfigurationKeysLoader.LoaderLoader.loadAllConfigurationKeys();
		this.messager = messager;
	}
	
	private static class VisitorContainer {
		private final JavacASTVisitor visitor;
		private final long priority;
		private final boolean resolutionResetNeeded;
		
		VisitorContainer(JavacASTVisitor visitor) {
			this.visitor = visitor;
			HandlerPriority hp = visitor.getClass().getAnnotation(HandlerPriority.class);
			this.priority = hp == null ? 0L : (((long) hp.value()) << 32) + hp.subValue();
			this.resolutionResetNeeded = visitor.getClass().isAnnotationPresent(ResolutionResetNeeded.class);
		}
		
		public long getPriority() {
			return priority;
		}
		
		public boolean isResolutionResetNeeded() {
			return resolutionResetNeeded;
		}
	}
	
	private static class AnnotationHandlerContainer<T extends Annotation> {
		private final JavacAnnotationHandler<T> handler;
		private final Class<T> annotationClass;
		private final long priority;
		private final boolean resolutionResetNeeded;
		private final boolean evenIfAlreadyHandled;
		
		AnnotationHandlerContainer(JavacAnnotationHandler<T> handler, Class<T> annotationClass) {
			this.handler = handler;
			this.annotationClass = annotationClass;
			HandlerPriority hp = handler.getClass().getAnnotation(HandlerPriority.class);
			this.priority = hp == null ? 0L : (((long)hp.value()) << 32) + hp.subValue();
			this.resolutionResetNeeded = handler.getClass().isAnnotationPresent(ResolutionResetNeeded.class);
			this.evenIfAlreadyHandled = handler.getClass().isAnnotationPresent(AlreadyHandledAnnotations.class);
		}
		
		public void handle(final JavacNode node) {
			handler.handle(JavacHandlerUtil.createAnnotation(annotationClass, node), (JCAnnotation)node.get(), node);
		}
		
		public long getPriority() {
			return priority;
		}
		
		public boolean isResolutionResetNeeded() {
			return resolutionResetNeeded;
		}
		
		public boolean isEvenIfAlreadyHandled() {
			return evenIfAlreadyHandled;
		}
	}
	
	private SortedSet<Long> priorities;
	private SortedSet<Long> prioritiesRequiringResolutionReset;
	
	public SortedSet<Long> getPriorities() {
		return priorities;
	}
	
	public SortedSet<Long> getPrioritiesRequiringResolutionReset() {
		return prioritiesRequiringResolutionReset;
	}
	
	private void calculatePriorities() {
		SortedSet<Long> set = new TreeSet<Long>();
		SortedSet<Long> resetNeeded = new TreeSet<Long>();
		for (List<AnnotationHandlerContainer<?>> containers : annotationHandlers.values()) {
			for (AnnotationHandlerContainer<?> container : containers) {
				set.add(container.getPriority());
				if (container.isResolutionResetNeeded()) resetNeeded.add(container.getPriority());
			}
		}
		for (VisitorContainer container : visitorHandlers) {
			set.add(container.getPriority());
			if (container.isResolutionResetNeeded()) resetNeeded.add(container.getPriority());
		}
		this.priorities = Collections.unmodifiableSortedSet(set);
		this.prioritiesRequiringResolutionReset = Collections.unmodifiableSortedSet(resetNeeded);
	}
	
	
Creates a new HandlerLibrary that will report any problems or errors to the provided messager,
then uses SPI discovery to load all annotation and visitor based handlers so that future calls
to the handle methods will defer to these handlers.
/**
	 * Creates a new HandlerLibrary that will report any problems or errors to the provided messager,
	 * then uses SPI discovery to load all annotation and visitor based handlers so that future calls
	 * to the handle methods will defer to these handlers.
	 */
	public static HandlerLibrary load(Messager messager, Trees trees) {
		HandlerLibrary library = new HandlerLibrary(messager);
		
		try {
			loadAnnotationHandlers(library, trees);
			loadVisitorHandlers(library, trees);
		} catch (IOException e) {
			System.err.println("Lombok isn't running due to misconfigured SPI files: " + e);
		}
		
		library.calculatePriorities();
		
		return library;
	}
	
	
Uses SPI Discovery to find implementations of JavacAnnotationHandler. /** Uses SPI Discovery to find implementations of {@link JavacAnnotationHandler}. */
	@SuppressWarnings({"rawtypes", "unchecked"})
	private static void loadAnnotationHandlers(HandlerLibrary lib, Trees trees) throws IOException {
		//No, that seemingly superfluous reference to JavacAnnotationHandler's classloader is not in fact superfluous!
		for (JavacAnnotationHandler handler : SpiLoadUtil.findServices(JavacAnnotationHandler.class, JavacAnnotationHandler.class.getClassLoader())) {
			handler.setTrees(trees);
			Class<? extends Annotation> annotationClass = handler.getAnnotationHandledByThisHandler();
			AnnotationHandlerContainer<?> container = new AnnotationHandlerContainer(handler, annotationClass);
			String annotationClassName = container.annotationClass.getName().replace("$", ".");
			List<AnnotationHandlerContainer<?>> list = lib.annotationHandlers.get(annotationClassName);
			if (list == null) lib.annotationHandlers.put(annotationClassName, list = new ArrayList<AnnotationHandlerContainer<?>>(1));
			list.add(container);
			lib.typeLibrary.addType(container.annotationClass.getName());
		}
	}
	
	
Uses SPI Discovery to find implementations of JavacASTVisitor. /** Uses SPI Discovery to find implementations of {@link JavacASTVisitor}. */
	private static void loadVisitorHandlers(HandlerLibrary lib, Trees trees) throws IOException {
		//No, that seemingly superfluous reference to JavacASTVisitor's classloader is not in fact superfluous!
		for (JavacASTVisitor visitor : SpiLoadUtil.findServices(JavacASTVisitor.class, JavacASTVisitor.class.getClassLoader())) {
			visitor.setTrees(trees);
			lib.visitorHandlers.add(new VisitorContainer(visitor));
		}
	}
	
	
Generates a warning in the Messager that was used to initialize this HandlerLibrary. /** Generates a warning in the Messager that was used to initialize this HandlerLibrary. */
	public void javacWarning(String message) {
		javacWarning(message, null);
	}
	
	
Generates a warning in the Messager that was used to initialize this HandlerLibrary. /** Generates a warning in the Messager that was used to initialize this HandlerLibrary. */
	public void javacWarning(String message, Throwable t) {
		messager.printMessage(Diagnostic.Kind.WARNING, message + (t == null ? "" : (": " + t)));
	}
	
	
Generates an error in the Messager that was used to initialize this HandlerLibrary. /** Generates an error in the Messager that was used to initialize this HandlerLibrary. */
	public void javacError(String message) {
		javacError(message, null);
	}
	
	
Generates an error in the Messager that was used to initialize this HandlerLibrary. /** Generates an error in the Messager that was used to initialize this HandlerLibrary. */
	public void javacError(String message, Throwable t) {
		messager.printMessage(Diagnostic.Kind.ERROR, message + (t == null ? "" : (": " + t)));
		if (t != null) t.printStackTrace();
	}
	
	private boolean checkAndSetHandled(JCTree node) {
		return !JCTree_handled.getAndSet(node, true);
	}
	
	
Handles the provided annotation node by first finding a qualifying instance of JavacAnnotationHandler and if one exists, calling it with a freshly cooked up instance of AnnotationValues. Note that depending on the printASTOnly flag, the PrintAST annotation will either be silently skipped, or everything that isn't PrintAST will be skipped. The HandlerLibrary will attempt to guess if the given annotation node represents a lombok annotation. For example, if lombok.* is in the import list, then this method will guess that Getter refers to lombok.Getter, presuming that HandleGetter has been loaded. 
Params:
unit – The Compilation Unit that contains the Annotation AST Node.
node – The Lombok AST Node representing the Annotation AST Node.
annotation – 'node.get()' - convenience parameter./**
	 * Handles the provided annotation node by first finding a qualifying instance of
	 * {@link JavacAnnotationHandler} and if one exists, calling it with a freshly cooked up
	 * instance of {@link lombok.core.AnnotationValues}.
	 * 
	 * Note that depending on the printASTOnly flag, the {@link lombok.core.PrintAST} annotation
	 * will either be silently skipped, or everything that isn't {@code PrintAST} will be skipped.
	 * 
	 * The HandlerLibrary will attempt to guess if the given annotation node represents a lombok annotation.
	 * For example, if {@code lombok.*} is in the import list, then this method will guess that
	 * {@code Getter} refers to {@code lombok.Getter}, presuming that {@link lombok.javac.handlers.HandleGetter}
	 * has been loaded.
	 * 
	 * @param unit The Compilation Unit that contains the Annotation AST Node.
	 * @param node The Lombok AST Node representing the Annotation AST Node.
	 * @param annotation 'node.get()' - convenience parameter.
	 */
	public void handleAnnotation(JCCompilationUnit unit, JavacNode node, JCAnnotation annotation, long priority) {
		TypeResolver resolver = new TypeResolver(node.getImportList());
		String rawType = annotation.annotationType.toString();
		String fqn = resolver.typeRefToFullyQualifiedName(node, typeLibrary, rawType);
		if (fqn == null) return;
		List<AnnotationHandlerContainer<?>> containers = annotationHandlers.get(fqn);
		if (containers == null) return;
		
		for (AnnotationHandlerContainer<?> container : containers) {
			try {
				if (container.getPriority() == priority) {
					if (checkAndSetHandled(annotation)) {
						container.handle(node);
					} else {
						if (container.isEvenIfAlreadyHandled()) container.handle(node);
					}
				}
			} catch (AnnotationValueDecodeFail fail) {
				fail.owner.setError(fail.getMessage(), fail.idx);
			} catch (Throwable t) {
				String sourceName = "(unknown).java";
				if (unit != null && unit.sourcefile != null) sourceName = unit.sourcefile.getName();
				javacError(String.format("Lombok annotation handler %s failed on " + sourceName, container.handler.getClass()), t);
			}
		}
	}
	
	
Will call all registered JavacASTVisitor instances. /**
	 * Will call all registered {@link JavacASTVisitor} instances.
	 */
	public void callASTVisitors(JavacAST ast, long priority) {
		for (VisitorContainer container : visitorHandlers) try {
			if (container.getPriority() == priority) ast.traverse(container.visitor);
		} catch (Throwable t) {
			javacError(String.format("Lombok visitor handler %s failed", container.visitor.getClass()), t);
		}
	}
}