/*
 * Copyright (C) 2015-2020 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.eclipse.handlers;

import static lombok.eclipse.handlers.EclipseHandlerUtil.*;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.jdt.internal.compiler.ast.ASTNode;
import org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration;
import org.eclipse.jdt.internal.compiler.ast.Annotation;
import org.eclipse.jdt.internal.compiler.ast.Argument;
import org.eclipse.jdt.internal.compiler.ast.Block;
import org.eclipse.jdt.internal.compiler.ast.ConditionalExpression;
import org.eclipse.jdt.internal.compiler.ast.EqualExpression;
import org.eclipse.jdt.internal.compiler.ast.Expression;
import org.eclipse.jdt.internal.compiler.ast.FieldDeclaration;
import org.eclipse.jdt.internal.compiler.ast.FieldReference;
import org.eclipse.jdt.internal.compiler.ast.IfStatement;
import org.eclipse.jdt.internal.compiler.ast.IntLiteral;
import org.eclipse.jdt.internal.compiler.ast.MessageSend;
import org.eclipse.jdt.internal.compiler.ast.NullLiteral;
import org.eclipse.jdt.internal.compiler.ast.OperatorIds;
import org.eclipse.jdt.internal.compiler.ast.ParameterizedQualifiedTypeReference;
import org.eclipse.jdt.internal.compiler.ast.ParameterizedSingleTypeReference;
import org.eclipse.jdt.internal.compiler.ast.QualifiedTypeReference;
import org.eclipse.jdt.internal.compiler.ast.Reference;
import org.eclipse.jdt.internal.compiler.ast.ReturnStatement;
import org.eclipse.jdt.internal.compiler.ast.SingleNameReference;
import org.eclipse.jdt.internal.compiler.ast.SingleTypeReference;
import org.eclipse.jdt.internal.compiler.ast.Statement;
import org.eclipse.jdt.internal.compiler.ast.ThisReference;
import org.eclipse.jdt.internal.compiler.ast.TypeReference;
import org.eclipse.jdt.internal.compiler.ast.Wildcard;
import org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
import org.eclipse.jdt.internal.compiler.lookup.TypeConstants;
import org.eclipse.jdt.internal.compiler.lookup.TypeIds;

import lombok.AccessLevel;
import lombok.core.LombokImmutableList;
import lombok.core.SpiLoadUtil;
import lombok.core.TypeLibrary;
import lombok.core.configuration.CheckerFrameworkVersion;
import lombok.eclipse.EclipseNode;
import lombok.eclipse.handlers.HandleBuilder.BuilderJob;

public class EclipseSingularsRecipes {
	public interface TypeReferenceMaker {
		TypeReference make();
	}
	
	public interface StatementMaker {
		Statement make();
	}
	
	private static final EclipseSingularsRecipes INSTANCE = new EclipseSingularsRecipes();
	private final Map<String, EclipseSingularizer> singularizers = new HashMap<String, EclipseSingularizer>();
	private final TypeLibrary singularizableTypes = new TypeLibrary();
	
	private EclipseSingularsRecipes() {
		try {
			loadAll(singularizableTypes, singularizers);
			singularizableTypes.lock();
		} catch (IOException e) {
			System.err.println("Lombok's @Singularizable feature is broken due to misconfigured SPI files: " + e);
		}
	}
	
	private static void loadAll(TypeLibrary library, Map<String, EclipseSingularizer> map) throws IOException {
		for (EclipseSingularizer handler : SpiLoadUtil.findServices(EclipseSingularizer.class, EclipseSingularizer.class.getClassLoader())) {
			for (String type : handler.getSupportedTypes()) {
				EclipseSingularizer existingSingularizer = map.get(type);
				if (existingSingularizer != null) {
					EclipseSingularizer toKeep = existingSingularizer.getClass().getName().compareTo(handler.getClass().getName()) > 0 ? handler : existingSingularizer;
					System.err.println("Multiple singularizers found for type " + type + "; the alphabetically first class is used: " + toKeep.getClass().getName());
					map.put(type, toKeep);
				} else {
					map.put(type, handler);
					library.addType(type);
				}
			}
		}
	}
	
	public static EclipseSingularsRecipes get() {
		return INSTANCE;
	}
	
	public String toQualified(String typeReference) {
		List<String> q = singularizableTypes.toQualifieds(typeReference);
		if (q.isEmpty()) return null;
		return q.get(0);
	}
	
	public EclipseSingularizer getSingularizer(String fqn) {
		return singularizers.get(fqn);
	}
	
	public static final class SingularData {
		private final EclipseNode annotation;
		private final char[] singularName;
		private final char[] pluralName;
		private final char[] setterPrefix;
		private final List<TypeReference> typeArgs;
		private final String targetFqn;
		private final EclipseSingularizer singularizer;
		private final boolean ignoreNullCollections;
		private final ASTNode source;
		
		public SingularData(EclipseNode annotation, char[] singularName, char[] pluralName, List<TypeReference> typeArgs, String targetFqn, EclipseSingularizer singularizer, ASTNode source, boolean ignoreNullCollections) {
			this(annotation, singularName, pluralName, typeArgs, targetFqn, singularizer, source, ignoreNullCollections, new char[0]);
		}
		
		public SingularData(EclipseNode annotation, char[] singularName, char[] pluralName, List<TypeReference> typeArgs, String targetFqn, EclipseSingularizer singularizer, ASTNode source, boolean ignoreNullCollections, char[] setterPrefix) {
			this.annotation = annotation;
			this.singularName = singularName;
			this.pluralName = pluralName;
			this.typeArgs = typeArgs;
			this.targetFqn = targetFqn;
			this.singularizer = singularizer;
			this.source = source;
			this.ignoreNullCollections = ignoreNullCollections;
			this.setterPrefix = setterPrefix;
		}
		
		public void setGeneratedByRecursive(ASTNode target) {
			SetGeneratedByVisitor visitor = new SetGeneratedByVisitor(source);
			
			if (target instanceof AbstractMethodDeclaration) {
				((AbstractMethodDeclaration) target).traverse(visitor, (ClassScope) null);
			} else if (target instanceof FieldDeclaration) {
				((FieldDeclaration) target).traverse(visitor, (MethodScope) null);
			} else {
				target.traverse(visitor, null);
			}
		}
		
		public ASTNode getSource() {
			return source;
		}
		
		public EclipseNode getAnnotation() {
			return annotation;
		}
		
		public char[] getSingularName() {
			return singularName;
		}
		
		public char[] getPluralName() {
			return pluralName;
		}
		
		public char[] getSetterPrefix() {
			return setterPrefix;
		}
		
		public List<TypeReference> getTypeArgs() {
			return typeArgs;
		}
		
		public String getTargetFqn() {
			return targetFqn;
		}
		
		public EclipseSingularizer getSingularizer() {
			return singularizer;
		}
		
		public boolean isIgnoreNullCollections() {
			return ignoreNullCollections;
		}
		
		public String getTargetSimpleType() {
			int idx = targetFqn.lastIndexOf(".");
			return idx == -1 ? targetFqn : targetFqn.substring(idx + 1);
		}
	}
	
	public static abstract class EclipseSingularizer {
		protected static final long[] NULL_POSS = {0L};
		public abstract LombokImmutableList<String> getSupportedTypes();
		
		
Checks if any of the to-be-generated nodes (fields, methods) already exist. If so, errors on these (singulars don't support manually writing some of it, and returns true). /** Checks if any of the to-be-generated nodes (fields, methods) already exist. If so, errors on these (singulars don't support manually writing some of it, and returns true). */
		public boolean checkForAlreadyExistingNodesAndGenerateError(EclipseNode builderType, SingularData data) {
			for (EclipseNode child : builderType.down()) {
				switch (child.getKind()) {
				case FIELD: {
					FieldDeclaration fd = (FieldDeclaration) child.get();
					char[] name = fd.name;
					if (name == null) continue;
					if (getGeneratedBy(fd) != null) continue;
					for (char[] fieldToBeGenerated : listFieldsToBeGenerated(data, builderType)) {
						if (!Arrays.equals(name, fieldToBeGenerated)) continue;
						child.addError("Manually adding a field that @Singular @Builder would generate is not supported. If you want to manually manage the builder aspect for this field/parameter, don't use @Singular.");
						return true;
					}
					break;
				}
				case METHOD: {
					AbstractMethodDeclaration method = (AbstractMethodDeclaration) child.get();
					char[] name = method.selector;
					if (name == null) continue;
					if (getGeneratedBy(method) != null) continue;
					for (char[] methodToBeGenerated : listMethodsToBeGenerated(data, builderType)) {
						if (!Arrays.equals(name, methodToBeGenerated)) continue;
						child.addError("Manually adding a method that @Singular @Builder would generate is not supported. If you want to manually manage the builder aspect for this field/parameter, don't use @Singular.");
						return true;
					}
					break;
				}}
			}
			
			return false;
		}
		
		public List<char[]> listFieldsToBeGenerated(SingularData data, EclipseNode builderType) {
			return Collections.singletonList(data.pluralName);
		}
		
		public List<char[]> listMethodsToBeGenerated(SingularData data, EclipseNode builderType) {
			char[] p = data.pluralName;
			char[] s = data.singularName;
			if (Arrays.equals(p, s)) return Collections.singletonList(p);
			return Arrays.asList(p, s);
		}
		
		public abstract List<EclipseNode> generateFields(SingularData data, EclipseNode builderType);
		
		
Generates the singular, plural, and clear methods for the given SingularData. Uses the given builderType as return type if chain == true, void otherwise. If you need more control over the return type and value, use generateMethods(CheckerFrameworkVersion, SingularData, boolean, EclipseNode, boolean, TypeReferenceMaker). /**
		 * Generates the singular, plural, and clear methods for the given {@link SingularData}.
		 * Uses the given {@code builderType} as return type if {@code chain == true}, {@code void} otherwise.
		 * If you need more control over the return type and value, use
		 * {@link #generateMethods(SingularData, boolean, EclipseNode, boolean, TypeReferenceMaker, StatementMaker)}.
		 */
		public void generateMethods(final BuilderJob job, SingularData data, boolean deprecate) {
			TypeReferenceMaker returnTypeMaker = new TypeReferenceMaker() {
				@Override public TypeReference make() {
					return job.oldChain ? cloneSelfType(job.builderType) : TypeReference.baseTypeReference(TypeIds.T_void, 0);
				}
			};
			
			StatementMaker returnStatementMaker = new StatementMaker() {
				@Override public ReturnStatement make() {
					return job.oldChain ? new ReturnStatement(new ThisReference(0, 0), 0, 0) : null;
				}
			};
			
			generateMethods(job.checkerFramework, data, deprecate, job.builderType, job.oldFluent, returnTypeMaker, returnStatementMaker, job.accessInners);
		}
		
		
Generates the singular, plural, and clear methods for the given SingularData. Uses the given returnTypeMaker and returnStatementMaker for the generated methods. /**
		 * Generates the singular, plural, and clear methods for the given {@link SingularData}.
		 * Uses the given {@code returnTypeMaker} and {@code returnStatementMaker} for the generated methods.
		 */
		public abstract void generateMethods(CheckerFrameworkVersion cfv, SingularData data, boolean deprecate, EclipseNode builderType, boolean fluent, TypeReferenceMaker returnTypeMaker, StatementMaker returnStatementMaker, AccessLevel access);
		
		public abstract void appendBuildCode(SingularData data, EclipseNode builderType, List<Statement> statements, char[] targetVariableName, String builderVariable);
		
		public boolean shadowedDuringBuild() {
			return true;
		}
		
		public boolean requiresCleaning() {
			try {
				return !getClass().getMethod("appendCleaningCode", SingularData.class, EclipseNode.class, List.class).getDeclaringClass().equals(EclipseSingularizer.class);
			} catch (NoSuchMethodException e) {
				return false;
			}
		}
		
		public void appendCleaningCode(SingularData data, EclipseNode builderType, List<Statement> statements) {
		}
		
		// -- Utility methods --
		
		protected Annotation[] generateSelfReturnAnnotations(boolean deprecate, CheckerFrameworkVersion cfv, ASTNode source) {
			Annotation deprecated = deprecate ? generateDeprecatedAnnotation(source) : null;
			Annotation returnsReceiver = cfv.generateReturnsReceiver() ? generateNamedAnnotation(source, CheckerFrameworkVersion.NAME__RETURNS_RECEIVER) : null;
			if (deprecated == null && returnsReceiver == null) return null;
			if (deprecated == null) return new Annotation[] {returnsReceiver};
			if (returnsReceiver == null) return new Annotation[] {deprecated};
			return new Annotation[] {deprecated, returnsReceiver};
		}
		
		
Adds the requested number of type arguments to the provided type, copying each argument in typeArgs. If typeArgs is too long, the extra elements are ignored. If typeArgs is null or too short, java.lang.Object will be substituted for each missing type argument. 
Params:
count – The number of type arguments requested.
addExtends – If true, all bounds are either '? extends X' or just '?'. If false, the reverse is applied, and '? extends Foo' is converted to Foo, '?' to Object, etc.
node – Some node in the same AST. Just used to obtain makers and contexts and such.
type – The type to add generics to.
typeArgs – the list of type args to clone.
source – The source annotation that is the root cause of this code generation./**
		 * Adds the requested number of type arguments to the provided type, copying each argument in {@code typeArgs}. If typeArgs is too long, the extra elements are ignored.
		 * If {@code typeArgs} is null or too short, {@code java.lang.Object} will be substituted for each missing type argument.
		 * 
		 * @param count The number of type arguments requested.
		 * @param addExtends If {@code true}, all bounds are either '? extends X' or just '?'. If false, the reverse is applied, and '? extends Foo' is converted to Foo, '?' to Object, etc.
		 * @param node Some node in the same AST. Just used to obtain makers and contexts and such.
		 * @param type The type to add generics to.
		 * @param typeArgs the list of type args to clone.
		 * @param source The source annotation that is the root cause of this code generation.
		 */
		protected TypeReference addTypeArgs(int count, boolean addExtends, EclipseNode node, TypeReference type, List<TypeReference> typeArgs) {
			TypeReference[] clonedAndFixedArgs = createTypeArgs(count, addExtends, node, typeArgs);
			if (type instanceof SingleTypeReference) {
				type = new ParameterizedSingleTypeReference(((SingleTypeReference) type).token, clonedAndFixedArgs, 0, 0L);
			} else if (type instanceof QualifiedTypeReference) {
				QualifiedTypeReference qtr = (QualifiedTypeReference) type;
				TypeReference[][] trs = new TypeReference[qtr.tokens.length][];
				trs[qtr.tokens.length - 1] = clonedAndFixedArgs;
				type = new ParameterizedQualifiedTypeReference(((QualifiedTypeReference) type).tokens, trs, 0, NULL_POSS);
			} else {
				node.addError("Don't know how to clone-and-parameterize type: " + type);
			}
			
			return type;
		}
		
		protected TypeReference[] createTypeArgs(int count, boolean addExtends, EclipseNode node, List<TypeReference> typeArgs) {
			if (count < 0) throw new IllegalArgumentException("count is negative");
			if (count == 0) return null;
			List<TypeReference> arguments = new ArrayList<TypeReference>();
			
			if (typeArgs != null) for (TypeReference orig : typeArgs) {
				Wildcard wildcard = orig instanceof Wildcard ? (Wildcard) orig : null;
				if (!addExtends) {
					if (wildcard != null && (wildcard.kind == Wildcard.UNBOUND || wildcard.kind == Wildcard.SUPER)) {
						arguments.add(new QualifiedTypeReference(TypeConstants.JAVA_LANG_OBJECT, NULL_POSS));
					} else if (wildcard != null && wildcard.kind == Wildcard.EXTENDS) {
						try {
							arguments.add(copyType(wildcard.bound));
						} catch (Exception e) {
							arguments.add(new QualifiedTypeReference(TypeConstants.JAVA_LANG_OBJECT, NULL_POSS));
						}
					} else {
						arguments.add(copyType(orig));
					}
				} else {
					if (wildcard != null && (wildcard.kind == Wildcard.UNBOUND || wildcard.kind == Wildcard.SUPER)) {
						Wildcard w = new Wildcard(Wildcard.UNBOUND);
						arguments.add(w);
					} else if (wildcard != null && wildcard.kind == Wildcard.EXTENDS) {
						arguments.add(copyType(orig));
					} else {
						Wildcard w = new Wildcard(Wildcard.EXTENDS);
						w.bound = copyType(orig);
						arguments.add(w);
					}
				}
				if (--count == 0) break;
			}
			
			while (count-- > 0) {
				if (addExtends) {
					arguments.add(new Wildcard(Wildcard.UNBOUND));
				} else {
					arguments.add(new QualifiedTypeReference(TypeConstants.JAVA_LANG_OBJECT, NULL_POSS));
				}
			}
			
			if (arguments.isEmpty()) return null;
			return arguments.toArray(new TypeReference[0]);
		}
		
		private static final char[] SIZE_TEXT = new char[] {'s', 'i', 'z', 'e'};
		
		
Generates 'this.name.size()' as an expression; if nullGuard is true, it's this.name == null ? 0 : this.name.size(). /** Generates 'this.<em>name</em>.size()' as an expression; if nullGuard is true, it's this.name == null ? 0 : this.name.size(). */
		protected Expression getSize(EclipseNode builderType, char[] name, boolean nullGuard, String builderVariable) {
			MessageSend invoke = new MessageSend();
			Reference thisRef = getBuilderReference(builderVariable);
			FieldReference thisDotName = new FieldReference(name, 0L);
			thisDotName.receiver = thisRef;
			invoke.receiver = thisDotName;
			invoke.selector = SIZE_TEXT;
			if (!nullGuard) return invoke;
			
			Reference cdnThisRef = getBuilderReference(builderVariable);
			FieldReference cdnThisDotName = new FieldReference(name, 0L);
			cdnThisDotName.receiver = cdnThisRef;
			NullLiteral nullLiteral = new NullLiteral(0, 0);
			EqualExpression isNull = new EqualExpression(cdnThisDotName, nullLiteral, OperatorIds.EQUAL_EQUAL);
			IntLiteral zeroLiteral = makeIntLiteral(new char[] {'0'}, null);
			ConditionalExpression conditional = new ConditionalExpression(isNull, zeroLiteral, invoke);
			return conditional;
		}
		
		protected TypeReference cloneParamType(int index, List<TypeReference> typeArgs, EclipseNode builderType) {
			if (typeArgs != null && typeArgs.size() > index) {
				TypeReference originalType = typeArgs.get(index);
				if (originalType instanceof Wildcard) {
					Wildcard wOriginalType = (Wildcard) originalType;
					if (wOriginalType.kind == Wildcard.EXTENDS) {
						try {
							return copyType(wOriginalType.bound);
						} catch (Exception e) {
							// fallthrough
						}
					}
				} else {
					return copyType(originalType);
				}
			}
			
			return new QualifiedTypeReference(TypeConstants.JAVA_LANG_OBJECT, NULL_POSS);
		}
		
		
Returns:
a SingleNameReference to the builder in the variable builderVariable. If {@ code builderVariable == "this"}, a ThisReference is returned./** @return a {@code SingleNameReference} to the builder in the variable <code>builderVariable</code>. If {@ code builderVariable == "this"}, a {@code ThisReference} is returned. */
		protected static Reference getBuilderReference(String builderVariable) {
			if ("this".equals(builderVariable)) {
				return new ThisReference(0, 0);
			} else {
				return new SingleNameReference(builderVariable.toCharArray(), 0);
			}
		}
		
		protected void nullBehaviorize(EclipseNode typeNode, SingularData data, List<Statement> statements, Argument arg) {
			boolean ignoreNullCollections = data.isIgnoreNullCollections();
			
			if (ignoreNullCollections) {
				Expression isNotNull = new EqualExpression(new SingleNameReference(data.getPluralName(), 0L), new NullLiteral(0, 0), OperatorIds.NOT_EQUAL);
				Block b = new Block(0);
				b.statements = statements.toArray(new Statement[statements.size()]);
				statements.clear();
				statements.add(new IfStatement(isNotNull, b, 0, 0));
				EclipseHandlerUtil.createRelevantNullableAnnotation(typeNode, arg);
				return;
			}
			
			EclipseHandlerUtil.createRelevantNonNullAnnotation(typeNode, arg);
			Statement nullCheck = EclipseHandlerUtil.generateNullCheck(null, data.getPluralName(), typeNode, "%s cannot be null");
			statements.add(0, nullCheck);
		}
		
		protected abstract char[][] getEmptyMakerReceiver(String targetFqn);
		protected abstract char[] getEmptyMakerSelector(String targetFqn);
	}
}