/*
 * Copyright (C) 2015-2018 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.handlers;

import static lombok.javac.Javac.*;
import static lombok.javac.handlers.JavacHandlerUtil.*;

import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCTypeParameter;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import lombok.ConfigurationKeys;
import lombok.core.LombokImmutableList;
import lombok.core.SpiLoadUtil;
import lombok.core.TypeLibrary;
import lombok.core.handlers.HandlerUtil;
import lombok.javac.JavacNode;
import lombok.javac.JavacTreeMaker;

import com.sun.source.tree.Tree.Kind;
import com.sun.tools.javac.code.BoundKind;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCModifiers;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.tree.JCTree.JCWildcard;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Name;

public class JavacSingularsRecipes {
	public interface ExpressionMaker {
		JCExpression make();
	}
	
	public interface StatementMaker {
		JCStatement make();
	}
	
	private static final JavacSingularsRecipes INSTANCE = new JavacSingularsRecipes();
	private final Map<String, JavacSingularizer> singularizers = new HashMap<String, JavacSingularizer>();
	private final TypeLibrary singularizableTypes = new TypeLibrary();
	
	private JavacSingularsRecipes() {
		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, JavacSingularizer> map) throws IOException {
		for (JavacSingularizer handler : SpiLoadUtil.findServices(JavacSingularizer.class, JavacSingularizer.class.getClassLoader())) {
			for (String type : handler.getSupportedTypes()) {
				JavacSingularizer existingSingularizer = map.get(type);
				if (existingSingularizer != null) {
					JavacSingularizer 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 JavacSingularsRecipes get() {
		return INSTANCE;
	}
	
	public String toQualified(String typeReference) {
		return singularizableTypes.toQualified(typeReference);
	}
	
	public JavacSingularizer getSingularizer(String fqn, JavacNode node) {
		final JavacSingularizer singularizer = singularizers.get(fqn);
		final boolean useGuavaInstead = Boolean.TRUE.equals(node.getAst().readConfiguration(ConfigurationKeys.SINGULAR_USE_GUAVA));
		return useGuavaInstead ? singularizer.getGuavaInstead(node) : singularizer;
	}
	
	public static final class SingularData {
		private final JavacNode annotation;
		private final Name singularName;
		private final Name pluralName;
		private final List<JCExpression> typeArgs;
		private final String targetFqn;
		private final JavacSingularizer singularizer;
		
		public SingularData(JavacNode annotation, Name singularName, Name pluralName, List<JCExpression> typeArgs, String targetFqn, JavacSingularizer singularizer) {
			this.annotation = annotation;
			this.singularName = singularName;
			this.pluralName = pluralName;
			this.typeArgs = typeArgs;
			this.targetFqn = targetFqn;
			this.singularizer = singularizer;
		}
		
		public JavacNode getAnnotation() {
			return annotation;
		}
		
		public Name getSingularName() {
			return singularName;
		}
		
		public Name getPluralName() {
			return pluralName;
		}
		
		public List<JCExpression> getTypeArgs() {
			return typeArgs;
		}
		
		public String getTargetFqn() {
			return targetFqn;
		}
		
		public JavacSingularizer getSingularizer() {
			return singularizer;
		}
		
		public String getTargetSimpleType() {
			int idx = targetFqn.lastIndexOf(".");
			return idx == -1 ? targetFqn : targetFqn.substring(idx + 1);
		}
	}
	
	public static abstract class JavacSingularizer {
		public abstract LombokImmutableList<String> getSupportedTypes();

		protected JavacSingularizer getGuavaInstead(JavacNode node) {
			return this;
		}
		
		protected JCModifiers makeMods(JavacTreeMaker maker, JavacNode node, boolean deprecate) {
			if (deprecate) return maker.Modifiers(Flags.PUBLIC, List.<JCAnnotation>of(maker.Annotation(genJavaLangTypeRef(node, "Deprecated"), List.<JCExpression>nil())));
			return maker.Modifiers(Flags.PUBLIC);
		}
		
		
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(JavacNode builderType, SingularData data) {
			for (JavacNode child : builderType.down()) {
				switch (child.getKind()) {
				case FIELD: {
					JCVariableDecl field = (JCVariableDecl) child.get();
					Name name = field.name;
					if (name == null) break;
					if (getGeneratedBy(field) != null) continue;
					for (Name fieldToBeGenerated : listFieldsToBeGenerated(data, builderType)) {
						if (!fieldToBeGenerated.equals(name)) 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: {
					JCMethodDecl method = (JCMethodDecl) child.get();
					Name name = method.name;
					if (name == null) break;
					if (getGeneratedBy(method) != null) continue;
					for (Name methodToBeGenerated : listMethodsToBeGenerated(data, builderType)) {
						if (!methodToBeGenerated.equals(name)) 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 java.util.List<Name> listFieldsToBeGenerated(SingularData data, JavacNode builderType) {
			return Collections.singletonList(data.pluralName);
		}
		
		public java.util.List<Name> listMethodsToBeGenerated(SingularData data, JavacNode builderType) {
			Name p = data.pluralName;
			Name s = data.singularName;
			if (p.equals(s)) return Collections.singletonList(p);
			return Arrays.asList(p, s);
		}
		
		public abstract java.util.List<JavacNode> generateFields(SingularData data, JavacNode builderType, JCTree source);
		
		
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(SingularData, boolean, JavacNode, JCTree, boolean, ExpressionMaker, StatementMaker). /**
		 * 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, JavacNode, JCTree, boolean, ExpressionMaker, StatementMaker)}.
		 */
		public void generateMethods(SingularData data, boolean deprecate, final JavacNode builderType, JCTree source, boolean fluent, final boolean chain) {
			final JavacTreeMaker maker = builderType.getTreeMaker();
			
			ExpressionMaker returnTypeMaker = new ExpressionMaker() { @Override public JCExpression make() {
				return chain ? 
					cloneSelfType(builderType) : 
					maker.Type(createVoidType(builderType.getSymbolTable(), CTC_VOID));
			}};
			
			StatementMaker returnStatementMaker = new StatementMaker() { @Override public JCStatement make() {
				return chain ? maker.Return(maker.Ident(builderType.toName("this"))) : null;
			}};
			
			generateMethods(data, deprecate, builderType, source, fluent, returnTypeMaker, returnStatementMaker);
		}
		
		
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(SingularData data, boolean deprecate, JavacNode builderType, JCTree source, boolean fluent, ExpressionMaker returnTypeMaker, StatementMaker returnStatementMaker);

		protected void doGenerateMethods(SingularData data, boolean deprecate, JavacNode builderType, JCTree source, boolean fluent, ExpressionMaker returnTypeMaker, StatementMaker returnStatementMaker) {
			JavacTreeMaker maker = builderType.getTreeMaker();
			generateSingularMethod(deprecate, maker, returnTypeMaker.make(), returnStatementMaker.make(), data, builderType, source, fluent);
			generatePluralMethod(deprecate, maker, returnTypeMaker.make(), returnStatementMaker.make(), data, builderType, source, fluent);
			generateClearMethod(deprecate, maker, returnTypeMaker.make(), returnStatementMaker.make(), data, builderType, source);
		}

		private void finishAndInjectMethod(JavacTreeMaker maker, JCExpression returnType, JCStatement returnStatement, SingularData data, JavacNode builderType, JCTree source, boolean deprecate, ListBuffer<JCStatement> statements, Name methodName, List<JCVariableDecl> jcVariableDecls) {
			if (returnStatement != null) statements.append(returnStatement);
			JCBlock body = maker.Block(0, statements.toList());
			JCModifiers mods = makeMods(maker, builderType, deprecate);
			List<JCTypeParameter> typeParams = List.nil();
			List<JCExpression> thrown = List.nil();
			JCMethodDecl method = maker.MethodDef(mods, methodName, returnType, typeParams, jcVariableDecls, thrown, body, null);
			recursiveSetGeneratedBy(method, source, builderType.getContext());
			injectMethod(builderType, method);
		}

		private void generateClearMethod(boolean deprecate, JavacTreeMaker maker, JCExpression returnType, JCStatement returnStatement, SingularData data, JavacNode builderType, JCTree source) {
			JCStatement clearStatement = generateClearStatements(maker, data, builderType);
			ListBuffer<JCStatement> statements = new ListBuffer<JCStatement>();
			statements.add(clearStatement);

			Name methodName = builderType.toName(HandlerUtil.buildAccessorName("clear", data.getPluralName().toString()));
			finishAndInjectMethod(maker, returnType, returnStatement, data, builderType, source, deprecate, statements, methodName, List.<JCVariableDecl>nil());
		}

		protected abstract JCStatement generateClearStatements(JavacTreeMaker maker, SingularData data, JavacNode builderType);

		private void generateSingularMethod(boolean deprecate, JavacTreeMaker maker, JCExpression returnType, JCStatement returnStatement, SingularData data, JavacNode builderType, JCTree source, boolean fluent) {
			ListBuffer<JCStatement> statements = generateSingularMethodStatements(maker, data, builderType, source);
			List<JCVariableDecl> params = generateSingularMethodParameters(maker, data, builderType, source);
			Name name = data.getSingularName();
			if (!fluent) name = builderType.toName(HandlerUtil.buildAccessorName(getAddMethodName(), name.toString()));

			statements.prepend(createConstructBuilderVarIfNeeded(maker, data, builderType, source));
			finishAndInjectMethod(maker, returnType, returnStatement, data, builderType, source, deprecate, statements, name, params);
		}

		protected JCVariableDecl generateSingularMethodParameter(int typeIndex, JavacTreeMaker maker, SingularData data, JavacNode builderType, JCTree source, Name name) {
			long flags = JavacHandlerUtil.addFinalIfNeeded(Flags.PARAMETER, builderType.getContext());
			JCExpression type = cloneParamType(typeIndex, maker, data.getTypeArgs(), builderType, source);
			List<JCAnnotation> typeUseAnns = getTypeUseAnnotations(type);
			type = removeTypeUseAnnotations(type);
			JCModifiers mods = typeUseAnns.isEmpty() ? maker.Modifiers(flags) : maker.Modifiers(flags, typeUseAnns);
			return maker.VarDef(mods, name, type, null);
		}

		protected JCStatement generateSingularMethodAddStatement(JavacTreeMaker maker, JavacNode builderType, Name argumentName, String builderFieldName) {
			JCExpression thisDotFieldDotAdd = chainDots(builderType, "this", builderFieldName, "add");
			JCExpression invokeAdd = maker.Apply(List.<JCExpression>nil(), thisDotFieldDotAdd, List.<JCExpression>of(maker.Ident(argumentName)));
			return maker.Exec(invokeAdd);
		}

		protected abstract ListBuffer<JCStatement> generateSingularMethodStatements(JavacTreeMaker maker, SingularData data, JavacNode builderType, JCTree source);

		protected abstract List<JCVariableDecl> generateSingularMethodParameters(JavacTreeMaker maker, SingularData data, JavacNode builderType, JCTree source);

		private void generatePluralMethod(boolean deprecate, JavacTreeMaker maker, JCExpression returnType, JCStatement returnStatement, SingularData data, JavacNode builderType, JCTree source, boolean fluent) {
			ListBuffer<JCStatement> statements = generatePluralMethodStatements(maker, data, builderType, source);
			Name name = data.getPluralName();
			if (!fluent) name = builderType.toName(HandlerUtil.buildAccessorName(getAddMethodName() + "All", name.toString()));
			JCExpression paramType = getPluralMethodParamType(builderType);
			paramType = addTypeArgs(getTypeArgumentsCount(), true, builderType, paramType, data.getTypeArgs(), source);
			long paramFlags = JavacHandlerUtil.addFinalIfNeeded(Flags.PARAMETER, builderType.getContext());
			JCVariableDecl param = maker.VarDef(maker.Modifiers(paramFlags), data.getPluralName(), paramType, null);
			statements.prepend(createConstructBuilderVarIfNeeded(maker, data, builderType, source));
			finishAndInjectMethod(maker, returnType, returnStatement, data, builderType, source, deprecate, statements, name, List.of(param));
		}

		protected ListBuffer<JCStatement> generatePluralMethodStatements(JavacTreeMaker maker, SingularData data, JavacNode builderType, JCTree source) {
			JCExpression thisDotFieldDotAdd = chainDots(builderType, "this", data.getPluralName().toString(), getAddMethodName() + "All");
			JCExpression invokeAdd = maker.Apply(List.<JCExpression>nil(), thisDotFieldDotAdd, List.<JCExpression>of(maker.Ident(data.getPluralName())));
			return new ListBuffer<JCStatement>().append(maker.Exec(invokeAdd));
		}

		protected abstract JCExpression getPluralMethodParamType(JavacNode builderType);

		protected abstract JCStatement createConstructBuilderVarIfNeeded(JavacTreeMaker maker, SingularData data, JavacNode builderType, JCTree source);

		public abstract void appendBuildCode(SingularData data, JavacNode builderType, JCTree source, ListBuffer<JCStatement> statements, Name targetVariableName, String builderVariable);
		
		public boolean requiresCleaning() {
			try {
				return !getClass().getMethod("appendCleaningCode", SingularData.class, JavacNode.class, JCTree.class, ListBuffer.class).getDeclaringClass().equals(JavacSingularizer.class);
			} catch (NoSuchMethodException e) {
				return false;
			}
		}
		
		public void appendCleaningCode(SingularData data, JavacNode builderType, JCTree source, ListBuffer<JCStatement> statements) {
		}
		
		// -- Utility methods --
		
		
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 JCExpression addTypeArgs(int count, boolean addExtends, JavacNode node, JCExpression type, List<JCExpression> typeArgs, JCTree source) {
			JavacTreeMaker maker = node.getTreeMaker();
			List<JCExpression> clonedAndFixedTypeArgs = createTypeArgs(count, addExtends, node, typeArgs, source);
			
			return maker.TypeApply(type, clonedAndFixedTypeArgs);
		}
		
		protected List<JCExpression> createTypeArgs(int count, boolean addExtends, JavacNode node, List<JCExpression> typeArgs, JCTree source) {
			JavacTreeMaker maker = node.getTreeMaker();
			Context context = node.getContext();
			
			if (count < 0) throw new IllegalArgumentException("count is negative");
			if (count == 0) return List.nil();
			ListBuffer<JCExpression> arguments = new ListBuffer<JCExpression>();
			
			if (typeArgs != null) for (JCExpression orig : typeArgs) {
				if (!addExtends) {
					if (orig.getKind() == Kind.UNBOUNDED_WILDCARD || orig.getKind() == Kind.SUPER_WILDCARD) {
						arguments.append(genJavaLangTypeRef(node, "Object"));
					} else if (orig.getKind() == Kind.EXTENDS_WILDCARD) {
						JCExpression inner;
						try {
							inner = (JCExpression) ((JCWildcard) orig).inner;
						} catch (Exception e) {
							inner = genJavaLangTypeRef(node, "Object");
						}
						arguments.append(cloneType(maker, inner, source, context));
					} else {
						arguments.append(cloneType(maker, orig, source, context));
					}
				} else {
					if (orig.getKind() == Kind.UNBOUNDED_WILDCARD || orig.getKind() == Kind.SUPER_WILDCARD) {
						arguments.append(maker.Wildcard(maker.TypeBoundKind(BoundKind.UNBOUND), null));
					} else if (orig.getKind() == Kind.EXTENDS_WILDCARD) {
						arguments.append(cloneType(maker, orig, source, context));
					} else {
						arguments.append(maker.Wildcard(maker.TypeBoundKind(BoundKind.EXTENDS), cloneType(maker, orig, source, context)));
					}
				}
				if (--count == 0) break;
			}
			
			while (count-- > 0) {
				if (addExtends) {
					arguments.append(maker.Wildcard(maker.TypeBoundKind(BoundKind.UNBOUND), null));
				} else {
					arguments.append(genJavaLangTypeRef(node, "Object"));
				}
			}
			
			return arguments.toList();
		}
		
		
Generates 'builderVariable.name.size()' as an expression; if nullGuard is true, it's this.name == null ? 0 : this.name.size(). /** Generates '<em>builderVariable</em>.<em>name</em>.size()' as an expression; if nullGuard is true, it's this.name == null ? 0 : this.name.size(). */
		protected JCExpression getSize(JavacTreeMaker maker, JavacNode builderType, Name name, boolean nullGuard, boolean parens, String builderVariable) {
			Name thisName = builderType.toName(builderVariable);
			JCExpression fn = maker.Select(maker.Select(maker.Ident(thisName), name), builderType.toName("size"));
			JCExpression sizeInvoke = maker.Apply(List.<JCExpression>nil(), fn, List.<JCExpression>nil());
			if (nullGuard) {
				JCExpression isNull = maker.Binary(CTC_EQUAL, maker.Select(maker.Ident(thisName), name), maker.Literal(CTC_BOT, 0));
				JCExpression out = maker.Conditional(isNull, maker.Literal(CTC_INT, 0), sizeInvoke);
				if (parens) return maker.Parens(out);
				return out;
			}
			return sizeInvoke;
		}
		
		protected JCExpression cloneParamType(int index, JavacTreeMaker maker, List<JCExpression> typeArgs, JavacNode builderType, JCTree source) {
			if (typeArgs == null || typeArgs.size() <= index) {
				return genJavaLangTypeRef(builderType, "Object");
			} else {
				JCExpression originalType = typeArgs.get(index);
				if (originalType.getKind() == Kind.UNBOUNDED_WILDCARD || originalType.getKind() == Kind.SUPER_WILDCARD) {
					return genJavaLangTypeRef(builderType, "Object");
				} else if (originalType.getKind() == Kind.EXTENDS_WILDCARD) {
					try {
						return cloneType(maker, (JCExpression) ((JCWildcard) originalType).inner, source, builderType.getContext());
					} catch (Exception e) {
						return genJavaLangTypeRef(builderType, "Object");
					}
				} else {
					return cloneType(maker, originalType, source, builderType.getContext());
				}
			}
		}

		protected abstract String getAddMethodName();

		protected abstract int getTypeArgumentsCount();
	}
}