/*
 * Copyright (C) 2009-2020 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.handlers;

import static lombok.core.handlers.HandlerUtil.*;
import static lombok.javac.Javac.*;
import static lombok.javac.JavacTreeMaker.TypeTag.*;
import static lombok.javac.handlers.JavacHandlerUtil.*;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import lombok.AccessLevel;
import lombok.ConfigurationKeys;
import lombok.experimental.Delegate;
import lombok.Getter;
import lombok.core.AST.Kind;
import lombok.core.AnnotationValues;
import lombok.core.configuration.CheckerFrameworkVersion;
import lombok.delombok.LombokOptionsFactory;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
import lombok.javac.JavacTreeMaker;
import lombok.javac.JavacTreeMaker.TypeTag;

import org.mangosdk.spi.ProviderFor;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCBinary;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCExpressionStatement;
import com.sun.tools.javac.tree.JCTree.JCIf;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
import com.sun.tools.javac.tree.JCTree.JCPrimitiveTypeTree;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCSynchronized;
import com.sun.tools.javac.tree.JCTree.JCTypeParameter;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Name;

Handles the lombok.Getter annotation for javac. /**
 * Handles the {@code lombok.Getter} annotation for javac.
 */
@ProviderFor(JavacAnnotationHandler.class)
public class HandleGetter extends JavacAnnotationHandler<Getter> {
	public void generateGetterForType(JavacNode typeNode, JavacNode errorNode, AccessLevel level, boolean checkForTypeLevelGetter, List<JCAnnotation> onMethod) {
		if (checkForTypeLevelGetter) {
			if (hasAnnotation(Getter.class, typeNode)) {
				//The annotation will make it happen, so we can skip it.
				return;
			}
		}
		
		JCClassDecl typeDecl = null;
		if (typeNode.get() instanceof JCClassDecl) typeDecl = (JCClassDecl) typeNode.get();
		long modifiers = typeDecl == null ? 0 : typeDecl.mods.flags;
		boolean notAClass = (modifiers & (Flags.INTERFACE | Flags.ANNOTATION)) != 0;
		
		if (typeDecl == null || notAClass) {
			errorNode.addError("@Getter is only supported on a class, an enum, or a field.");
			return;
		}
		
		for (JavacNode field : typeNode.down()) {
			if (fieldQualifiesForGetterGeneration(field)) generateGetterForField(field, errorNode.get(), level, false, onMethod);
		}
	}
	
	public static boolean fieldQualifiesForGetterGeneration(JavacNode field) {
		if (field.getKind() != Kind.FIELD) return false;
		JCVariableDecl fieldDecl = (JCVariableDecl) field.get();
		//Skip fields that start with $
		if (fieldDecl.name.toString().startsWith("$")) return false;
		//Skip static fields.
		if ((fieldDecl.mods.flags & Flags.STATIC) != 0) return false;
		return true;
	}
	
	
Generates a getter on the stated field. Used by HandleData. The difference between this call and the handle method is as follows: If there is a lombok.Getter annotation on the field, it is used and the same rules apply (e.g. warning if the method already exists, stated access level applies). If not, the getter is still generated if it isn't already there, though there will not be a warning if its already there. The default access level is used. 
Params:
fieldNode – The node representing the field you want a getter for.
pos – The node responsible for generating the getter (the @Data or @Getter annotation)./**
	 * Generates a getter on the stated field.
	 * 
	 * Used by {@link HandleData}.
	 * 
	 * The difference between this call and the handle method is as follows:
	 * 
	 * If there is a {@code lombok.Getter} annotation on the field, it is used and the
	 * same rules apply (e.g. warning if the method already exists, stated access level applies).
	 * If not, the getter is still generated if it isn't already there, though there will not
	 * be a warning if its already there. The default access level is used.
	 * 
	 * @param fieldNode The node representing the field you want a getter for.
	 * @param pos The node responsible for generating the getter (the {@code @Data} or {@code @Getter} annotation).
	 */
	public void generateGetterForField(JavacNode fieldNode, DiagnosticPosition pos, AccessLevel level, boolean lazy, List<JCAnnotation> onMethod) {
		if (hasAnnotation(Getter.class, fieldNode)) {
			//The annotation will make it happen, so we can skip it.
			return;
		}
		createGetterForField(level, fieldNode, fieldNode, false, lazy, onMethod);
	}
	
	@Override public void handle(AnnotationValues<Getter> annotation, JCAnnotation ast, JavacNode annotationNode) {
		handleFlagUsage(annotationNode, ConfigurationKeys.GETTER_FLAG_USAGE, "@Getter");
		
		Collection<JavacNode> fields = annotationNode.upFromAnnotationToFields();
		deleteAnnotationIfNeccessary(annotationNode, Getter.class);
		deleteImportFromCompilationUnit(annotationNode, "lombok.AccessLevel");
		JavacNode node = annotationNode.up();
		Getter annotationInstance = annotation.getInstance();
		AccessLevel level = annotationInstance.value();
		boolean lazy = annotationInstance.lazy();
		if (lazy) handleFlagUsage(annotationNode, ConfigurationKeys.GETTER_LAZY_FLAG_USAGE, "@Getter(lazy=true)");
		
		if (level == AccessLevel.NONE) {
			if (lazy) annotationNode.addWarning("'lazy' does not work with AccessLevel.NONE.");
			return;
		}
		
		if (node == null) return;
		
		List<JCAnnotation> onMethod = unboxAndRemoveAnnotationParameter(ast, "onMethod", "@Getter(onMethod", annotationNode);
		
		switch (node.getKind()) {
		case FIELD:
			createGetterForFields(level, fields, annotationNode, true, lazy, onMethod);
			break;
		case TYPE:
			if (lazy) annotationNode.addError("'lazy' is not supported for @Getter on a type.");
			generateGetterForType(node, annotationNode, level, false, onMethod);
			break;
		}
	}
	
	public void createGetterForFields(AccessLevel level, Collection<JavacNode> fieldNodes, JavacNode errorNode, boolean whineIfExists, boolean lazy, List<JCAnnotation> onMethod) {
		for (JavacNode fieldNode : fieldNodes) {
			createGetterForField(level, fieldNode, errorNode, whineIfExists, lazy, onMethod);
		}
	}
	
	public void createGetterForField(AccessLevel level,
			JavacNode fieldNode, JavacNode source, boolean whineIfExists, boolean lazy, List<JCAnnotation> onMethod) {
		
		if (fieldNode.getKind() != Kind.FIELD) {
			source.addError("@Getter is only supported on a class or a field.");
			return;
		}
		
		JCVariableDecl fieldDecl = (JCVariableDecl)fieldNode.get();
		
		if (lazy) {
			if ((fieldDecl.mods.flags & Flags.PRIVATE) == 0 || (fieldDecl.mods.flags & Flags.FINAL) == 0) {
				source.addError("'lazy' requires the field to be private and final.");
				return;
			}
			if ((fieldDecl.mods.flags & Flags.TRANSIENT) != 0) {
				source.addError("'lazy' is not supported on transient fields.");
				return;
			}
			if (fieldDecl.init == null) {
				source.addError("'lazy' requires field initialization.");
				return;
			}
		}
		
		String methodName = toGetterName(fieldNode);
		
		if (methodName == null) {
			source.addWarning("Not generating getter for this field: It does not fit your @Accessors prefix list.");
			return;
		}
		
		for (String altName : toAllGetterNames(fieldNode)) {
			switch (methodExists(altName, fieldNode, false, 0)) {
			case EXISTS_BY_LOMBOK:
				return;
			case EXISTS_BY_USER:
				if (whineIfExists) {
					String altNameExpl = "";
					if (!altName.equals(methodName)) altNameExpl = String.format(" (%s)", altName);
					source.addWarning(
						String.format("Not generating %s(): A method with that name already exists%s", methodName, altNameExpl));
				}
				return;
			default:
			case NOT_EXISTS:
				//continue scanning the other alt names.
			}
		}
		
		long access = toJavacModifier(level) | (fieldDecl.mods.flags & Flags.STATIC);
		
		injectMethod(fieldNode.up(), createGetter(access, fieldNode, fieldNode.getTreeMaker(), source.get(), lazy, onMethod), List.<Type>nil(), getMirrorForFieldType(fieldNode));
	}
	
	public JCMethodDecl createGetter(long access, JavacNode field, JavacTreeMaker treeMaker, JCTree source, boolean lazy, List<JCAnnotation> onMethod) {
		JCVariableDecl fieldNode = (JCVariableDecl) field.get();
		
		// Remember the type; lazy will change it
		JCExpression methodType = cloneType(treeMaker, copyType(treeMaker, fieldNode), source, field.getContext());
		// Generate the methodName; lazy will change the field type
		Name methodName = field.toName(toGetterName(field));
		
		List<JCStatement> statements;
		JCTree toClearOfMarkers = null;
		int[] methodArgPos = null;
		boolean addSuppressWarningsUnchecked = false;
		if (lazy && !inNetbeansEditor(field)) {
			toClearOfMarkers = fieldNode.init;
			if (toClearOfMarkers instanceof JCMethodInvocation) {
				List<JCExpression> args = ((JCMethodInvocation) toClearOfMarkers).args;
				methodArgPos = new int[args.length()];
				for (int i = 0; i < methodArgPos.length; i++) {
					methodArgPos[i] = args.get(i).pos;
				}
			}
			statements = createLazyGetterBody(treeMaker, field, source);
			addSuppressWarningsUnchecked = LombokOptionsFactory.getDelombokOptions(field.getContext()).getFormatPreferences().generateSuppressWarnings();
		} else {
			statements = createSimpleGetterBody(treeMaker, field);
		}
		
		JCBlock methodBody = treeMaker.Block(0, statements);
		
		List<JCTypeParameter> methodGenericParams = List.nil();
		List<JCVariableDecl> parameters = List.nil();
		List<JCExpression> throwsClauses = List.nil();
		JCExpression annotationMethodDefaultValue = null;
		
		List<JCAnnotation> copyableAnnotations = findCopyableAnnotations(field);
		List<JCAnnotation> delegates = findDelegatesAndRemoveFromField(field);
		List<JCAnnotation> annsOnMethod = copyAnnotations(onMethod).appendList(copyableAnnotations);
		if (field.isFinal()) {
			if (getCheckerFrameworkVersion(field).generatePure()) annsOnMethod = annsOnMethod.prepend(treeMaker.Annotation(genTypeRef(field, CheckerFrameworkVersion.NAME__PURE), List.<JCExpression>nil()));
		} else {
			if (getCheckerFrameworkVersion(field).generateSideEffectFree()) annsOnMethod = annsOnMethod.prepend(treeMaker.Annotation(genTypeRef(field, CheckerFrameworkVersion.NAME__SIDE_EFFECT_FREE), List.<JCExpression>nil()));
		}
		if (isFieldDeprecated(field)) annsOnMethod = annsOnMethod.prepend(treeMaker.Annotation(genJavaLangTypeRef(field, "Deprecated"), List.<JCExpression>nil()));
		
		JCMethodDecl decl = recursiveSetGeneratedBy(treeMaker.MethodDef(treeMaker.Modifiers(access, annsOnMethod), methodName, methodType,
			methodGenericParams, parameters, throwsClauses, methodBody, annotationMethodDefaultValue), source, field.getContext());
		
		if (toClearOfMarkers != null) recursiveSetGeneratedBy(toClearOfMarkers, null, null);
		if (methodArgPos != null) {
			for (int i = 0; i < methodArgPos.length; i++) {
				((JCMethodInvocation) toClearOfMarkers).args.get(i).pos = methodArgPos[i];
			}
		}
		decl.mods.annotations = decl.mods.annotations.appendList(delegates);
		
		if (addSuppressWarningsUnchecked) {
			ListBuffer<JCExpression> suppressions = new ListBuffer<JCExpression>();
			if (!Boolean.FALSE.equals(field.getAst().readConfiguration(ConfigurationKeys.ADD_SUPPRESSWARNINGS_ANNOTATIONS))) {
				suppressions.add(treeMaker.Literal("all"));
			}
			suppressions.add(treeMaker.Literal("unchecked"));
			addAnnotation(decl.mods, field, source.pos, source, field.getContext(), "java.lang.SuppressWarnings", treeMaker.NewArray(null, List.<JCExpression>nil(), suppressions.toList()));
		}
		
		copyJavadoc(field, decl, CopyJavadoc.GETTER);
		return decl;
	}
	
	public static List<JCAnnotation> findDelegatesAndRemoveFromField(JavacNode field) {
		JCVariableDecl fieldNode = (JCVariableDecl) field.get();
		
		List<JCAnnotation> delegates = List.nil();
		for (JCAnnotation annotation : fieldNode.mods.annotations) {
			if (typeMatches(Delegate.class, field, annotation.annotationType)) {
				delegates = delegates.append(annotation);
			}
		}
		
		if (!delegates.isEmpty()) {
			ListBuffer<JCAnnotation> withoutDelegates = new ListBuffer<JCAnnotation>();
			for (JCAnnotation annotation : fieldNode.mods.annotations) {
				if (!delegates.contains(annotation)) {
					withoutDelegates.append(annotation);
				}
			}
			fieldNode.mods.annotations = withoutDelegates.toList();
			field.rebuild();
		}
		return delegates;
	}
	
	public List<JCStatement> createSimpleGetterBody(JavacTreeMaker treeMaker, JavacNode field) {
		return List.<JCStatement>of(treeMaker.Return(createFieldAccessor(treeMaker, field, FieldAccess.ALWAYS_FIELD)));
	}
	
	private static final String AR = "java.util.concurrent.atomic.AtomicReference";
	private static final List<JCExpression> NIL_EXPRESSION = List.nil();
	
	public static final java.util.Map<TypeTag, String> TYPE_MAP;
	static {
		Map<TypeTag, String> m = new HashMap<TypeTag, String>();
		m.put(CTC_INT, "Integer");
		m.put(CTC_DOUBLE, "Double");
		m.put(CTC_FLOAT, "Float");
		m.put(CTC_SHORT, "Short");
		m.put(CTC_BYTE, "Byte");
		m.put(CTC_LONG, "Long");
		m.put(CTC_BOOLEAN, "Boolean");
		m.put(CTC_CHAR, "Character");
		TYPE_MAP = Collections.unmodifiableMap(m);
	}
	
	public List<JCStatement> createLazyGetterBody(JavacTreeMaker maker, JavacNode fieldNode, JCTree source) {
		/*
		java.lang.Object value = this.fieldName.get();
		if (value == null) {
			synchronized (this.fieldName) {
				value = this.fieldName.get();
				if (value == null) {
					final RawValueType actualValue = INITIALIZER_EXPRESSION;
					[IF PRIMITIVE]
					value = actualValue;
					[ELSE]
					value = actualValue == null ? this.fieldName : actualValue;
					[END IF]
					this.fieldName.set(value);
				}
			}
		}
		[IF PRIMITIVE]
		return (BoxedValueType) value;
		[ELSE]
		return (BoxedValueType) (value == this.fieldName ? null : value);
		[END IF]
		*/
		
		ListBuffer<JCStatement> statements = new ListBuffer<JCStatement>();
		
		JCVariableDecl field = (JCVariableDecl) fieldNode.get();
		JCExpression copyOfRawFieldType = copyType(maker, field);
		JCExpression copyOfBoxedFieldType = null;
		field.type = null;
		boolean isPrimitive = false;
		if (field.vartype instanceof JCPrimitiveTypeTree) {
			String boxed = TYPE_MAP.get(typeTag(field.vartype));
			if (boxed != null) {
				isPrimitive = true;
				field.vartype = genJavaLangTypeRef(fieldNode, boxed);
				copyOfBoxedFieldType = genJavaLangTypeRef(fieldNode, boxed);
			}
		}
		if (copyOfBoxedFieldType == null) copyOfBoxedFieldType = copyType(maker, field);
		
		Name valueName = fieldNode.toName("value");
		Name actualValueName = fieldNode.toName("actualValue");
		
		/* java.lang.Object value = this.fieldName.get();*/ {
			JCExpression valueVarType = genJavaLangTypeRef(fieldNode, "Object");
			statements.append(maker.VarDef(maker.Modifiers(0L), valueName, valueVarType, callGet(fieldNode, createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD))));
		}
		
		/* if (value == null) { */ {
			JCSynchronized synchronizedStatement;
			/* synchronized (this.fieldName) { */ {
				ListBuffer<JCStatement> synchronizedStatements = new ListBuffer<JCStatement>();
				/* value = this.fieldName.get(); */ {
					JCExpressionStatement newAssign = maker.Exec(maker.Assign(maker.Ident(valueName), callGet(fieldNode, createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD))));
					synchronizedStatements.append(newAssign);
				}
				
				/* if (value == null) { */ {
					ListBuffer<JCStatement> innerIfStatements = new ListBuffer<JCStatement>();
					/* final RawValueType actualValue = INITIALIZER_EXPRESSION; */ {
						innerIfStatements.append(maker.VarDef(maker.Modifiers(Flags.FINAL), actualValueName, copyOfRawFieldType, field.init));
					}
					/* [IF primitive] value = actualValue; */ {
						if (isPrimitive) {
							JCStatement statement = maker.Exec(maker.Assign(maker.Ident(valueName), maker.Ident(actualValueName)));
							innerIfStatements.append(statement);
						}
					}
					/* [ELSE] value = actualValue == null ? this.fieldName : actualValue; */ {
						if (!isPrimitive) {
							JCExpression actualValueIsNull = maker.Binary(CTC_EQUAL, maker.Ident(actualValueName), maker.Literal(CTC_BOT, null));
							JCExpression thisDotFieldName = createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD);
							JCExpression ternary = maker.Conditional(actualValueIsNull, thisDotFieldName, maker.Ident(actualValueName));
							JCStatement statement = maker.Exec(maker.Assign(maker.Ident(valueName), ternary));
							innerIfStatements.append(statement);
						}
					}
					/* this.fieldName.set(value); */ {
						JCStatement statement = callSet(fieldNode, createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD), maker.Ident(valueName));
						innerIfStatements.append(statement);
					}
					
					JCBinary isNull = maker.Binary(CTC_EQUAL, maker.Ident(valueName), maker.Literal(CTC_BOT, null));
					JCIf ifStatement = maker.If(isNull, maker.Block(0, innerIfStatements.toList()), null);
					synchronizedStatements.append(ifStatement);
				}
				
				synchronizedStatement = maker.Synchronized(createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD), maker.Block(0, synchronizedStatements.toList()));
			}
			
			JCBinary isNull = maker.Binary(CTC_EQUAL, maker.Ident(valueName), maker.Literal(CTC_BOT, null));
			JCIf ifStatement = maker.If(isNull, maker.Block(0, List.<JCStatement>of(synchronizedStatement)), null);
			statements.append(ifStatement);
		}
		/* [IF PRIMITIVE] return (BoxedValueType) value; */ {
			if (isPrimitive) {
				statements.append(maker.Return(maker.TypeCast(copyOfBoxedFieldType, maker.Ident(valueName))));
			}
		}
		/* [ELSE] return (BoxedValueType) (value == this.fieldName ? null : value); */ {
			if (!isPrimitive) {
				JCExpression valueEqualsSelf = maker.Binary(CTC_EQUAL, maker.Ident(valueName), createFieldAccessor(maker, fieldNode, FieldAccess.ALWAYS_FIELD));
				JCExpression ternary = maker.Conditional(valueEqualsSelf, maker.Literal(CTC_BOT,  null), maker.Ident(valueName));
				JCExpression typeCast = maker.TypeCast(copyOfBoxedFieldType, maker.Parens(ternary));
				statements.append(maker.Return(typeCast));
			}
		}
		
		// update the field type and init last
		
		/*	private final java.util.concurrent.atomic.AtomicReference<Object> fieldName = new java.util.concurrent.atomic.AtomicReference<Object>(); */ {
			field.vartype = recursiveSetGeneratedBy(
				maker.TypeApply(chainDotsString(fieldNode, AR), List.<JCExpression>of(genJavaLangTypeRef(fieldNode, "Object"))), source, fieldNode.getContext());
			field.init = recursiveSetGeneratedBy(maker.NewClass(null, NIL_EXPRESSION, copyType(maker, field), NIL_EXPRESSION, null), source, fieldNode.getContext());
		}
		
		return statements.toList();
	}
	
	public JCMethodInvocation callGet(JavacNode source, JCExpression receiver) {
		JavacTreeMaker maker = source.getTreeMaker();
		return maker.Apply(NIL_EXPRESSION, maker.Select(receiver, source.toName("get")), NIL_EXPRESSION);
	}
	
	public JCStatement callSet(JavacNode source, JCExpression receiver, JCExpression value) {
		JavacTreeMaker maker = source.getTreeMaker();
		return maker.Exec(maker.Apply(NIL_EXPRESSION, maker.Select(receiver, source.toName("set")), List.<JCExpression>of(value)));
	}
	
	public JCExpression copyType(JavacTreeMaker treeMaker, JCVariableDecl fieldNode) {
		return fieldNode.type != null ? treeMaker.Type(fieldNode.type) : fieldNode.vartype;
	}
}