/*
 * Copyright (C) 2010-2021 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.eclipse.handlers;

import static lombok.core.handlers.HandlerUtil.handleFlagUsage;
import static lombok.eclipse.handlers.EclipseHandlerUtil.*;

import lombok.ConfigurationKeys;
import lombok.val;
import lombok.var;
import lombok.core.HandlerPriority;
import lombok.eclipse.DeferUntilPostDiet;
import lombok.eclipse.Eclipse;
import lombok.eclipse.EclipseASTAdapter;
import lombok.eclipse.EclipseASTVisitor;
import lombok.eclipse.EclipseNode;
import lombok.spi.Provides;

import org.eclipse.jdt.internal.compiler.ast.ASTNode;
import org.eclipse.jdt.internal.compiler.ast.ArrayInitializer;
import org.eclipse.jdt.internal.compiler.ast.ForStatement;
import org.eclipse.jdt.internal.compiler.ast.ForeachStatement;
import org.eclipse.jdt.internal.compiler.ast.LocalDeclaration;
import org.eclipse.jdt.internal.compiler.ast.NullLiteral;
import org.eclipse.jdt.internal.compiler.ast.SingleTypeReference;
import org.eclipse.jdt.internal.compiler.ast.TypeReference;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;

/*
 * Java 1-9: This class just handles 3 basic error cases. The real meat of eclipse 'val' support is in {@code PatchVal} and {@code PatchValEclipse}.
 * Java 10+: Lombok uses the native 'var' support and transforms 'val' to 'final var'.
 */
@Provides(EclipseASTVisitor.class)
@DeferUntilPostDiet
@HandlerPriority(65536) // 2^16; resolution needs to work, so if the RHS expression is i.e. a call to a generated getter, we have to run after that getter has been generated.
public class HandleVal extends EclipseASTAdapter {
	@Override public void visitLocal(EclipseNode localNode, LocalDeclaration local) {
		TypeReference type = local.type;
		boolean isVal = typeMatches(val.class, localNode, type);
		boolean isVar = typeMatches(var.class, localNode, type);
		if (!(isVal || isVar)) return;
		
		if (isVal) handleFlagUsage(localNode, ConfigurationKeys.VAL_FLAG_USAGE, "val");
		if (isVar) handleFlagUsage(localNode, ConfigurationKeys.VAR_FLAG_USAGE, "var");
		
		boolean variableOfForEach = false;
		
		if (localNode.directUp().get() instanceof ForeachStatement) {
			ForeachStatement fs = (ForeachStatement) localNode.directUp().get();
			variableOfForEach = fs.elementVariable == local;
		}
		
		String annotation = isVal ? "val" : "var";
		if (local.initialization == null && !variableOfForEach) {
			localNode.addError("'" + annotation + "' on a local variable requires an initializer expression");
			return;
		}
		
		if (local.initialization instanceof ArrayInitializer) {
			localNode.addError("'" + annotation + "' is not compatible with array initializer expressions. Use the full form (new int[] { ... } instead of just { ... })");
			return;
		}
		
		ASTNode parentRaw = localNode.directUp().get();
		
		if (isVal && parentRaw instanceof ForStatement) {
			localNode.addError("'val' is not allowed in old-style for loops");
			return;
		}
		
		if (parentRaw instanceof ForStatement && ((ForStatement) parentRaw).initializations != null && ((ForStatement) parentRaw).initializations.length > 1) {
			localNode.addError("'var' is not allowed in old-style for loops if there is more than 1 initializer");
			return;
		}
		
		if (local.initialization != null && local.initialization.getClass().getName().equals("org.eclipse.jdt.internal.compiler.ast.LambdaExpression")) {
			localNode.addError("'" + annotation + "' is not allowed with lambda expressions.");
			return;
		}
		
		if(isVar && local.initialization instanceof NullLiteral) {
			localNode.addError("variable initializer is 'null'");
			return;
		}
		
		// For Java >= 10 we use native support
		if (localNode.getSourceVersion() >= 10) {
			if (isVal) {
				TypeReference originalType = local.type;
				local.type = new SingleTypeReference("var".toCharArray(), Eclipse.pos(local.type));
				local.modifiers |= ClassFileConstants.AccFinal;
				local.annotations = addAnnotation(local.type, local.annotations, originalType.getTypeName());
			}
			return;
		}
	}
}