/*
 * Copyright 2009-2016 the original author or authors.
 *
 * Licensed 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.jdt.groovy.internal.compiler.ast;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import groovy.lang.GroovyClassLoader;

import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.classgen.GeneratorContext;
import org.codehaus.groovy.control.CompilationFailedException;
import org.codehaus.groovy.control.CompilationUnit.PrimaryClassNodeOperation;
import org.codehaus.groovy.control.SourceUnit;

// Andys version of GrailsAwareInjectionOperation
// FIXASC ensure we have a grails nature and a way to determine grails level
/**
 * In Grails 1.1 an extra compiler phase is added to the compiler by grails. During compilation this phase operation adds properties
 * like 'identity' to domain objects, based upon whether they are in the directory grails-app/domain. Under Grails 1.2 this is a
 * global ast transform, but in order for things to work properly under 1.1, we have this injector operation. Without a grails
 * nature (which we may have shortly), the decision about whether this injector should be added to any compiler is based upon with a
 * grails-app folder exists in the project (crude, but it works). Once added it will try and access the real grails injector via
 * reflection - caching results to try and limit performance issues. If anything goes wrong it moves to a broken state and no longer
 * attempts anything. This is probably likely to happen for users on Grails 1.2 since the signature of the method will have changed.
 * For M2 we should determine what level of grails a project is and created the nature.
 *
 * @author Andy Clement
 * @since 2.0
 */
public class GrailsInjector extends PrimaryClassNodeOperation {

    private GroovyClassLoader groovyClassLoader;

    // If true then some part of the reflection has broken down so avoid trying again
    private boolean broken = false;

    private Class<?> /* DefaultGrailsDomainClassInjector */injectorClazz;
    private Object/* DefaultGrailsDomainClassInjector */injectorInstance;
    private Method injectorMethod;

    public GrailsInjector(GroovyClassLoader groovyClassLoader) {
        this.groovyClassLoader = groovyClassLoader;
    }

    @Override
    public void call(SourceUnit sourceUnit, GeneratorContext context, ClassNode classNode) throws CompilationFailedException {
        if (broken) {
            return;
        }
        if (injectorClazz == null) {
            // Attempt to load the grails class
            try {
                injectorClazz = groovyClassLoader
                        .loadClass("org.codehaus.groovy.grails.compiler.injection.DefaultGrailsDomainClassInjector");
                injectorInstance = injectorClazz.newInstance();
            } catch (Throwable t) {
                broken = true;
                System.err
                        .println("GrailsInjector: Unable to load and create 'org.codehaus.groovy.grails.compiler.injection.DefaultGrailsDomainClassInjector'");
                t.printStackTrace();
                return;
            }
            try {
                // retrieve the method we want
                injectorMethod = injectorClazz.getDeclaredMethod("performInjection", new Class[] { SourceUnit.class,
                        GeneratorContext.class, ClassNode.class });
            } catch (SecurityException se) {
                broken = true;
                System.err
                        .println("GrailsInjector: Cannot find correct performInjection method on 'org.codehaus.groovy.grails.compiler.injection.DefaultGrailsDomainClassInjector'");
                se.printStackTrace();
                return;
            } catch (NoSuchMethodException nsme) {
                broken = true;
                System.err
                        .println("GrailsInjector: Cannot find correct performInjection method on 'org.codehaus.groovy.grails.compiler.injection.DefaultGrailsDomainClassInjector'");
                nsme.printStackTrace();
                return;
            }
            if (injectorMethod == null) {
                broken = true;
                return;
            }
        }

        try {
            // Check if it should be run - rather crude check but will cover the basics I think
            if (sourceUnit.getName().indexOf("grails-app/domain/") != -1) {
                injectorMethod.invoke(injectorInstance, sourceUnit, context, classNode);
            }
        } catch (IllegalArgumentException iae) {
            System.err.println("GrailsInjector: Problem invoking performInjection");
            iae.printStackTrace();
        } catch (IllegalAccessException iae) {
            System.err.println("GrailsInjector: Problem invoking performInjection");
            iae.printStackTrace();
        } catch (InvocationTargetException e) {
            System.err.println("GrailsInjector: Problem invoking performInjection");
            e.printStackTrace();
        }
    }
}