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 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 */
package org.codehaus.groovy.control.customizers

import groovy.transform.AutoFinal
import groovy.transform.CompilationUnitAware
import org.codehaus.groovy.ast.ASTNode
import org.codehaus.groovy.ast.AnnotationNode
import org.codehaus.groovy.ast.ClassHelper
import org.codehaus.groovy.ast.ClassNode
import org.codehaus.groovy.ast.expr.Expression
import org.codehaus.groovy.classgen.GeneratorContext
import org.codehaus.groovy.control.CompilationUnit
import org.codehaus.groovy.control.CompilePhase
import org.codehaus.groovy.control.SourceUnit
import org.codehaus.groovy.transform.ASTTransformation
import org.codehaus.groovy.transform.GroovyASTTransformation
import org.codehaus.groovy.transform.GroovyASTTransformationClass

import java.lang.annotation.Annotation

import static org.codehaus.groovy.ast.tools.GeneralUtils.classX
import static org.codehaus.groovy.ast.tools.GeneralUtils.constX
import static org.codehaus.groovy.ast.tools.GeneralUtils.listX
import static org.codehaus.groovy.ast.tools.GeneralUtils.propX

/**
 * This customizer allows applying an AST transformation to a source unit with
 * several strategies.
 *
 * Creating a customizer with the {@link ASTTransformationCustomizer#ASTTransformationCustomizer(Class)
 * class constructor} will trigger an AST transformation for
 * each class node of a source unit. However, you cannot pass parameters to the annotation so the default values
 * will be used. Writing :
 * <pre>
 *     def configuration = new CompilerConfiguration()
 *     configuration.addCompilationCustomizers(new ASTTransformationCustomizer(Log))
 *     def shell = new GroovyShell(configuration)
 *     shell.evaluate("""
 *        class MyClass {
 *
 *        }""")
 * </pre>
 *
 * is equivalent to :
 *
 * <pre>
 *     def shell = new GroovyShell()
 *     shell.evaluate("""
 *        &#64;Log
 *        class MyClass {
 *
 *        }""")
 * </pre>
 *
 * The class passed as a constructor parameter must be an AST transformation annotation.
 *
 * Alternatively, you can apply a global AST transformation by calling the
 * {@link ASTTransformationCustomizer#ASTTransformationCustomizer(ASTTransformation) AST transformation
 * constructor}. In that case, the transformation is applied once for the whole source unit.
 *
 * Unlike a global AST transformation declared in the META-INF/services/org.codehaus.groovy.transform.ASTTransformation
 * file, which are applied if the file is in the classpath, using this customizer you'll have the choice to apply
 * your transformation selectively. It can also be useful to debug global AST transformations without having to
 * package your annotation in a jar file.
 *
 * @since 1.8.0
 * 
 */
@AutoFinal
class ASTTransformationCustomizer extends CompilationCustomizer implements CompilationUnitAware {

    private boolean applied // global xforms
    protected CompilationUnit compilationUnit
    private final AnnotationNode annotationNode
            final ASTTransformation transformation

    /**
     * Creates an AST transformation customizer using the specified annotation. The transformation classloader can
     * be used if the transformation class cannot be loaded from the same class loader as the annotation class.
     * It's assumed that the annotation is not annotated with {@code GroovyASTTransformationClass} and so the
     * second argument supplies the link to the ASTTransformation class that should be used.
     * @param transformationAnnotation
     * @param astTransformationClassName
     * @param transformationClassLoader
     */
    ASTTransformationCustomizer(Class<? extends Annotation> transformationAnnotation, String astTransformationClassName, ClassLoader transformationClassLoader) {
        super(findPhase(transformationAnnotation, astTransformationClassName, transformationClassLoader))
        Class<ASTTransformation> clazz = findASTTransformationClass(transformationAnnotation, astTransformationClassName, transformationClassLoader)
        this.transformation = clazz.newInstance()
        this.annotationNode = new AnnotationNode(ClassHelper.make(transformationAnnotation))
    }

    /**
     * Creates an AST transformation customizer using the specified annotation. It's assumed that the annotation
     * is not annotated with {@code GroovyASTTransformationClass} and so the second argument supplies the link to
     * the ASTTransformation class that should be used.
     * @param transformationAnnotation
     * @param astTransformationClassName
     */
    ASTTransformationCustomizer(Class<? extends Annotation> transformationAnnotation, String astTransformationClassName) {
        this(transformationAnnotation, astTransformationClassName, transformationAnnotation.classLoader)
    }

    /**
     * Creates an AST transformation customizer using the specified annotation. The transformation classloader can
     * be used if the transformation class cannot be loaded from the same class loader as the annotation class.
     * Additionally, you can pass a map of parameters that will be used to parameterize the annotation.
     * It's assumed that the annotation is not annotated with {@code GroovyASTTransformationClass} and so the
     * second argument supplies the link to the ASTTransformation class that should be used.
     * @param transformationAnnotation
     * @param astTransformationClassName
     * @param transformationClassLoader
     */
    ASTTransformationCustomizer(Map annotationParams, Class<? extends Annotation> transformationAnnotation, String astTransformationClassName, ClassLoader transformationClassLoader) {
        super(findPhase(transformationAnnotation, astTransformationClassName, transformationClassLoader))
        Class<ASTTransformation> clazz = findASTTransformationClass(transformationAnnotation, astTransformationClassName, transformationClassLoader)
        this.transformation = clazz.newInstance()
        this.annotationNode = new AnnotationNode(ClassHelper.make(transformationAnnotation))
        this.annotationParameters = annotationParams
    }

    ASTTransformationCustomizer(Map annotationParams, Class<? extends Annotation> transformationAnnotation, String astTransformationClassName) {
        this(annotationParams, transformationAnnotation, transformationAnnotation.classLoader)
    }

    /**
     * Creates an AST transformation customizer using the specified annotation. The transformation classloader can
     * be used if the transformation class cannot be loaded from the same class loader as the annotation class.
     * @param transformationAnnotation
     * @param transformationClassLoader
     */
    ASTTransformationCustomizer(Class<? extends Annotation> transformationAnnotation, ClassLoader transformationClassLoader) {
        super(findPhase(transformationAnnotation, transformationClassLoader))
        Class<ASTTransformation> clazz = findASTTransformationClass(transformationAnnotation, transformationClassLoader)
        this.transformation = clazz.newInstance()
        this.annotationNode = new AnnotationNode(ClassHelper.make(transformationAnnotation))
    }

    /**
     * Creates an AST transformation customizer using the specified annotation.
     * @param transformationAnnotation
     */
    ASTTransformationCustomizer(Class<? extends Annotation> transformationAnnotation) {
        this(transformationAnnotation, transformationAnnotation.classLoader)
    }

    /**
     * Creates an AST transformation customizer using the specified transformation.
     */
    ASTTransformationCustomizer(ASTTransformation transformation) {
        super(findPhase(transformation))
        this.transformation = transformation
        this.annotationNode = null
    }

    /**
     * Creates an AST transformation customizer using the specified annotation. The transformation classloader can
     * be used if the transformation class cannot be loaded from the same class loader as the annotation class.
     * Additionally, you can pass a map of parameters that will be used to parameterize the annotation.
     * @param transformationAnnotation
     * @param transformationClassLoader
     */
    ASTTransformationCustomizer(Map annotationParams, Class<? extends Annotation> transformationAnnotation, ClassLoader transformationClassLoader) {
        super(findPhase(transformationAnnotation, transformationClassLoader))
        Class<ASTTransformation> clazz = findASTTransformationClass(transformationAnnotation, transformationClassLoader)
        this.transformation = clazz.newInstance()
        this.annotationNode = new AnnotationNode(ClassHelper.make(transformationAnnotation))
        this.annotationParameters = annotationParams
    }

    ASTTransformationCustomizer(Map annotationParams, Class<? extends Annotation> transformationAnnotation) {
        this(annotationParams, transformationAnnotation, transformationAnnotation.classLoader)
    }

    ASTTransformationCustomizer(Map annotationParams, ASTTransformation transformation) {
        this(transformation)
        this.annotationParameters = annotationParams
    }

    void setCompilationUnit(CompilationUnit unit) {
        compilationUnit = unit
    }

    @SuppressWarnings('ClassForName')
    private static Class<ASTTransformation> findASTTransformationClass(Class<? extends Annotation> anAnnotationClass, ClassLoader transformationClassLoader) {
        GroovyASTTransformationClass annotation = anAnnotationClass.getAnnotation(GroovyASTTransformationClass)
        if (annotation == null) throw new IllegalArgumentException("Provided class doesn't look like an AST @interface")

        Class[] classes = annotation.classes()
        String[] classesAsStrings = annotation.value()
        if (classes.length + classesAsStrings.length > 1) {
            throw new IllegalArgumentException("AST transformation customizer doesn't support AST transforms with multiple classes")
        }
        classes ? classes[0] : Class.forName(classesAsStrings[0], true, transformationClassLoader ?: anAnnotationClass.classLoader)
    }

    @SuppressWarnings('ClassForName')
    private static Class<ASTTransformation> findASTTransformationClass(Class<? extends Annotation> anAnnotationClass, String astTransformationClassName, ClassLoader transformationClassLoader) {
        Class.forName(astTransformationClassName, true, transformationClassLoader ?: anAnnotationClass.classLoader) as Class<ASTTransformation>
    }

    private static CompilePhase findPhase(ASTTransformation transformation) {
        if (transformation == null) throw new IllegalArgumentException('Provided transformation must not be null')
        Class<?> clazz = transformation.class
        GroovyASTTransformation annotation = clazz.getAnnotation(GroovyASTTransformation)
        if (annotation == null) throw new IllegalArgumentException("Provided ast transformation is not annotated with $GroovyASTTransformation.name")

        annotation.phase()
    }

    private static CompilePhase findPhase(Class<? extends Annotation> annotationClass, ClassLoader transformationClassLoader) {
        Class<ASTTransformation> clazz = findASTTransformationClass(annotationClass, transformationClassLoader)

        findPhase(clazz.newInstance())
    }

    private static CompilePhase findPhase(Class<? extends Annotation> annotationClass, String astTransformationClassName, ClassLoader transformationClassLoader) {
        Class<ASTTransformation> clazz = findASTTransformationClass(annotationClass, astTransformationClassName, transformationClassLoader)

        findPhase(clazz.newInstance())
    }

    /**
     * Specify annotation parameters. For example, if the annotation is:
     * <pre>@Log(value='logger')</pre>
     * You could create an AST transformation customizer and specify the "value" parameter thanks to this method:
     * <pre>annotationParameters = [value: 'logger']</pre>
     *
     * Note that you cannot specify annotation closure values directly. If the annotation you want to add takes
     * a closure as an argument, you will have to set a {@link ClosureExpression} instead. This can be done by either
     * creating a custom {@link ClosureExpression} from code, or using the {@link org.codehaus.groovy.ast.builder.AstBuilder}.
     * <p>
     * Here is an example:
     * <pre>
     * // add @Contract({distance >= 0 })
     * def customizer = new ASTTransformationCustomizer(Contract)
     * def expression = new AstBuilder().buildFromCode(CompilePhase.CONVERSION) { ->
     *    distance >= 0
     * }.expression[0]
     * customizer.annotationParameters = [value: expression]</pre>
     *
     * @param params the annotation parameters
     *
     * @since 1.8.1
     */
    void setAnnotationParameters(Map<String, Object> params) {
        if (annotationNode == null || params == null || params.isEmpty()) return
        params.each { name, value ->
            if (!annotationNode.classNode.getMethod(name)) {
                throw new IllegalArgumentException("${annotationNode.classNode.name} does not accept any [$name] parameter")
            }
            if (value instanceof Closure) {
                throw new IllegalArgumentException('Direct usage of closure is not supported by the AST compilation customizer. Please use ClosureExpression instead.')
            }

            Expression valueExpression

            if (value instanceof Expression) {
                valueExpression = value
                // avoid NPEs due to missing source code
                value.lineNumber = 0; value.lastLineNumber = 0
            } else if (value instanceof Class) {
                valueExpression = classX(value)
            } else if (value instanceof Enum) {
                valueExpression = propX(classX(ClassHelper.make(value.getClass())), value.toString())
            } else if (value instanceof List || value.getClass().isArray()) {
                valueExpression = listX(value.collect { it instanceof Class ? classX(it) : constX(it) })
            } else {
                valueExpression = constX(value)
            }

            annotationNode.addMember(name, valueExpression)
        }
    }

    @Override
    void call(SourceUnit source, GeneratorContext context, ClassNode classNode) {
        if (transformation instanceof CompilationUnitAware) {
            transformation.compilationUnit = compilationUnit
        }
        if (annotationNode != null) {
            // this is a local ast transformation which is applied on every class node
            annotationNode.sourcePosition = classNode
            transformation.visit([annotationNode, classNode] as ASTNode[], source)
        } else {
            // this is a global AST transformation
            if (!applied) transformation.visit(null, source)
        }
        applied = true
    }
}
