/*
 * Copyright © 2009 Reinier Zwitserloot and Roel Spilker.
 * 
 * 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.eclipse.agent;

import java.lang.instrument.Instrumentation;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import lombok.patcher.Hook;
import lombok.patcher.MethodTarget;
import lombok.patcher.ScriptManager;
import lombok.patcher.StackRequest;
import lombok.patcher.TargetMatcher;
import lombok.patcher.equinox.EquinoxClassLoader;
import lombok.patcher.scripts.ScriptBuilder;

/**
 * This is a java-agent that patches some of eclipse's classes so AST Nodes are handed off to Lombok
 * for modification before Eclipse actually uses them to compile, render errors, show code outlines,
 * create auto-completion dialogs, and anything else eclipse does with java code. See the *Transformer
 * classes in this package for more information about which classes are transformed and how they are
 * transformed.
 */
public class EclipsePatcher {
	private EclipsePatcher() {}
	
	public static void agentmain(String agentArgs, Instrumentation instrumentation) throws Exception {
		registerPatchScripts(instrumentation, true);
	}
	
	public static void premain(String agentArgs, Instrumentation instrumentation) throws Exception {
		registerPatchScripts(instrumentation, false);
	}
	
	private static void registerPatchScripts(Instrumentation instrumentation, boolean reloadExistingClasses) {
		ScriptManager sm = new ScriptManager();
		sm.registerTransformer(instrumentation);
		EquinoxClassLoader.getInstance().addPrefix("lombok.");
		EquinoxClassLoader.getInstance().registerScripts(sm);
		
		patchLombokizeAST(sm);
		patchAvoidReparsingGeneratedCode(sm);
		patchCatchReparse(sm);
		patchSetGeneratedFlag(sm);
		patchHideGeneratedNodes(sm);
		
		if (reloadExistingClasses) sm.reloadClasses(instrumentation);
	}

	private static void patchHideGeneratedNodes(ScriptManager sm) {
		sm.addScript(ScriptBuilder.wrapReturnValue()
				.target(new MethodTarget("org.eclipse.jdt.internal.corext.dom.LinkedNodeFinder", "findByNode"))
				.target(new MethodTarget("org.eclipse.jdt.internal.corext.dom.LinkedNodeFinder", "findByBinding"))
				.wrapMethod(new Hook("lombok/eclipse/agent/PatchFixes", "removeGeneratedSimpleNames",
						"([Lorg/eclipse/jdt/core/dom/SimpleName;)[Lorg/eclipse/jdt/core/dom/SimpleName;"))
				.request(StackRequest.RETURN_VALUE).build());
		
		sm.addScript(ScriptBuilder.exitEarly()
				.target(new MethodTarget("org.eclipse.jdt.core.dom.rewrite.ASTRewrite", "replace"))
				.target(new MethodTarget("org.eclipse.jdt.core.dom.rewrite.ASTRewrite", "remove"))
				.decisionMethod(new Hook("lombok/eclipse/agent/PatchFixes", "skipRewritingGeneratedNodes",
						"(Lorg/eclipse/jdt/core/dom/ASTNode;)Z"))
				.transplant().request(StackRequest.PARAM1).build());
		
		sm.addScript(ScriptBuilder.wrapMethodCall()
				.target(new MethodTarget("org.eclipse.jdt.internal.corext.refactoring.rename.RenameTypeProcessor", "addConstructorRenames"))
				.methodToWrap(new Hook("org/eclipse/jdt/core/IType", "getMethods", "()[Lorg/eclipse/jdt/core/IMethod;"))
				.wrapMethod(new Hook("lombok/eclipse/agent/PatchFixes", "removeGeneratedMethods", 
						"([Lorg/eclipse/jdt/core/IMethod;)[Lorg/eclipse/jdt/core/IMethod;"))
				.transplant().build());
	}

	private static void patchCatchReparse(ScriptManager sm) {
		sm.addScript(ScriptBuilder.wrapReturnValue()
				.target(new MethodTarget("org.eclipse.jdt.core.dom.ASTConverter", "retrieveStartingCatchPosition"))
				.wrapMethod(new Hook("lombok/eclipse/agent/PatchFixes", "fixRetrieveStartingCatchPosition", "(I)I"))
				.transplant().request(StackRequest.PARAM1).build());
	}

	private static void patchSetGeneratedFlag(ScriptManager sm) {
		sm.addScript(ScriptBuilder.addField()
				.targetClass("org.eclipse.jdt.internal.compiler.ast.ASTNode")
				.fieldName("$generatedBy")
				.fieldType("Lorg/eclipse/jdt/internal/compiler/ast/ASTNode;")
				.setPublic().setTransient().build());
		
		sm.addScript(ScriptBuilder.addField()
				.targetClass("org.eclipse.jdt.core.dom.ASTNode")
				.fieldName("$isGenerated").fieldType("Z")
				.setPublic().setTransient().build());
		
		sm.addScript(ScriptBuilder.wrapReturnValue()
				.target(new TargetMatcher() {
					@Override public boolean matches(String classSpec, String methodName, String descriptor) {
						if (!"convert".equals(methodName)) return false;
						
						List<String> fullDesc = MethodTarget.decomposeFullDesc(descriptor);
						if ("V".equals(fullDesc.get(0))) return false;
						if (fullDesc.size() < 2) return false;
						if (!fullDesc.get(1).startsWith("Lorg/eclipse/jdt/internal/compiler/ast/")) return false;
						return true;
					}
					
					@Override public Collection<String> getAffectedClasses() {
						return Collections.singleton("org.eclipse.jdt.core.dom.ASTConverter");
					}
				}).request(StackRequest.PARAM1, StackRequest.RETURN_VALUE)
				.wrapMethod(new Hook("lombok/eclipse/agent/PatchFixes", "setIsGeneratedFlag",
						"(Lorg/eclipse/jdt/core/dom/ASTNode;Lorg/eclipse/jdt/internal/compiler/ast/ASTNode;)V"))
				.transplant().build());
		
		sm.addScript(ScriptBuilder.wrapMethodCall()
				.target(new TargetMatcher() {
					@Override public boolean matches(String classSpec, String methodName, String descriptor) {
						if (!methodName.startsWith("convert")) return false;
						
						List<String> fullDesc = MethodTarget.decomposeFullDesc(descriptor);
						if (fullDesc.size() < 2) return false;
						if (!fullDesc.get(1).startsWith("Lorg/eclipse/jdt/internal/compiler/ast/")) return false;
						
						return true;
					}
					
					@Override public Collection<String> getAffectedClasses() {
						return Collections.singleton("org.eclipse.jdt.core.dom.ASTConverter");
					}
				}).methodToWrap(new Hook("org/eclipse/jdt/core/dom/SimpleName", "<init>", "(Lorg/eclipse/jdt/core/dom/AST;)V"))
				.requestExtra(StackRequest.PARAM1)
				.wrapMethod(new Hook("lombok/eclipse/agent/PatchFixes", "setIsGeneratedFlagForSimpleName",
						"(Lorg/eclipse/jdt/core/dom/SimpleName;Ljava/lang/Object;)V"))
				.transplant().build());
	}

	private static void patchAvoidReparsingGeneratedCode(ScriptManager sm) {
		final String PARSER_SIG1 = "org.eclipse.jdt.internal.compiler.parser.Parser";
		sm.addScript(ScriptBuilder.exitEarly()
				.target(new MethodTarget(PARSER_SIG1, "parse", "void",
						"org.eclipse.jdt.internal.compiler.ast.MethodDeclaration",
						"org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration"))
				.decisionMethod(new Hook("lombok/eclipse/agent/PatchFixes", "checkBit24", "(Ljava/lang/Object;)Z"))
				.transplant().request(StackRequest.PARAM1).build());
		
		sm.addScript(ScriptBuilder.exitEarly()
				.target(new MethodTarget(PARSER_SIG1, "parse", "void",
						"org.eclipse.jdt.internal.compiler.ast.ConstructorDeclaration",
						"org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration", "boolean"))
				.decisionMethod(new Hook("lombok/eclipse/agent/PatchFixes", "checkBit24", "(Ljava/lang/Object;)Z"))
				.transplant().request(StackRequest.PARAM1).build());
		
		sm.addScript(ScriptBuilder.exitEarly()
				.target(new MethodTarget(PARSER_SIG1, "parse", "void",
						"org.eclipse.jdt.internal.compiler.ast.Initializer",
						"org.eclipse.jdt.internal.compiler.ast.TypeDeclaration",
						"org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration"))
				.decisionMethod(new Hook("lombok/eclipse/agent/PatchFixes", "checkBit24", "(Ljava/lang/Object;)Z"))
				.transplant().request(StackRequest.PARAM1).build());
	}

	private static void patchLombokizeAST(ScriptManager sm) {
		sm.addScript(ScriptBuilder.addField()
				.targetClass("org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration")
				.fieldName("$lombokAST").fieldType("Ljava/lang/Object;")
				.setPublic().setTransient().build());
		
		final String PARSER_SIG1 = "org.eclipse.jdt.internal.compiler.parser.Parser";
		final String PARSER_SIG2 = "Lorg/eclipse/jdt/internal/compiler/parser/Parser;";
		final String CUD_SIG1 = "org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration";
		final String CUD_SIG2 = "Lorg/eclipse/jdt/internal/compiler/ast/CompilationUnitDeclaration;";
		
		sm.addScript(ScriptBuilder.wrapReturnValue()
				.target(new MethodTarget(PARSER_SIG1, "getMethodBodies", "void", CUD_SIG1))
				.wrapMethod(new Hook("lombok/eclipse/TransformEclipseAST", "transform",
						"(" + PARSER_SIG2 + CUD_SIG2 + ")V"))
				.request(StackRequest.THIS, StackRequest.PARAM1).build());
		
		sm.addScript(ScriptBuilder.wrapReturnValue()
				.target(new MethodTarget(PARSER_SIG1, "endParse", CUD_SIG1, "int"))
				.wrapMethod(new Hook("lombok/eclipse/TransformEclipseAST", "transform_swapped",
						"(" + CUD_SIG2 + PARSER_SIG2 + ")V"))
				.request(StackRequest.THIS, StackRequest.RETURN_VALUE).build());
	}
}