/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
/*
 *
 * @author Toni Kalajainen
 */
package org.simantics.g2d.canvas.impl;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import org.simantics.g2d.canvas.SGDesignation;
import org.simantics.scenegraph.g2d.G2DParentNode;


public class SGNodeReflection {

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.METHOD)
    public static @interface SGInit {
        SGDesignation designation() default SGDesignation.CANVAS;
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.METHOD)
    public static @interface SGCleanup {
    }

    /**
     * Scans an object with reflection for all painter methods and returns
     * an array of ICanvasPainters and priorities.
     * <p>
     * The corresponding class of obj must contain methods that meet the following
     * criteria:
     *  1) no return value
     *  2) 1 argument, which is Graphics2D
     *  3) has annotation Painter
     *  4) may not throw any Exception
     *  5) method must be accessible
     * <p>
     * Example:
     *
     * 	@Painter(priority = Integer.MIN_VALUE)
     *  public void prePaint(GraphicsContext gc) {
     *  }
     *
     * @param obj object to scan
     * @return an array of painters and their priorities
     */
    public static CanvasSGNodeDefinition[] getSGHandlers(final Object obj)
    {
        List<CanvasSGNodeDefinition> result = new ArrayList<CanvasSGNodeDefinition>();
        Class<?> clazz = obj.getClass();

        for (final Method m : clazz.getMethods()) {
            SGInit initAnno = m.getAnnotation(SGInit.class);
            if (initAnno==null) continue;

            SGDesignation initDesignation = initAnno.designation();

            Class<?> returnType = m.getReturnType();
            if (!returnType.equals(void.class))
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" return type is invalid");

            @SuppressWarnings("rawtypes")
            Class[] argTypes = m.getParameterTypes();
            if (argTypes.length!=1 || !argTypes[0].equals(G2DParentNode.class))
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" invalid arguments");

            @SuppressWarnings("rawtypes")
            Class[] exceptionTypes = m.getExceptionTypes();
            if (exceptionTypes.length!=0)
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" invalid exceptions");

            try {
                m.setAccessible(true);
            } catch (Throwable t)
            {
                t.printStackTrace();
                throw new Error(t);
            }

            CanvasSGNodeDefinition def = new CanvasSGNodeDefinition(m, initDesignation, null, obj);
            result.add(def);
        }

        for (final Method m : clazz.getMethods()) {
            SGCleanup cleanupAnno = m.getAnnotation(SGCleanup.class);
            if (cleanupAnno==null) continue;

            Class<?> returnType = m.getReturnType();
            if (!returnType.equals(void.class))
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" return type is invalid");

            @SuppressWarnings("rawtypes")
            Class[] argTypes = m.getParameterTypes();
            if (argTypes.length!=0)
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" invalid arguments");

            @SuppressWarnings("rawtypes")
            Class[] exceptionTypes = m.getExceptionTypes();
            if (exceptionTypes.length!=0)
                throw new RuntimeException(clazz.getName()+"."+m.getName()+" invalid exceptions");

            try {
                m.setAccessible(true);
            } catch (Throwable t)
            {
                t.printStackTrace();
                throw new Error(t);
            }

            CanvasSGNodeDefinition def = new CanvasSGNodeDefinition(null, null, m, obj);
            result.add(def);
        }

        return result.toArray(new CanvasSGNodeDefinition[0]);
    }

    public static class CanvasSGNodeDefinition { // FIXME: own classes for init and cleanup
        public final Method initMethod;
        public final SGDesignation initDesignation;
        public final Method cleanupMethod;
        public final Object obj;

        public void init(G2DParentNode parent) {
            if(initMethod == null) return;
            try {
                initMethod.invoke(obj, parent);
            } catch (IllegalArgumentException e) {
                throw new Error(e);
            } catch (IllegalAccessException e) {
                throw new Error(e);
            } catch (InvocationTargetException e) {
                throw new RuntimeException(e.getCause());
            }
        }
        public void cleanup() {
            if(cleanupMethod == null) return;
            try {
                cleanupMethod.invoke(obj);
            } catch (IllegalArgumentException e) {
                throw new Error(e);
            } catch (IllegalAccessException e) {
                throw new Error(e);
            } catch (InvocationTargetException e) {
                throw new RuntimeException(e.getCause());
            }
        }
        public CanvasSGNodeDefinition(Method initMethod, SGDesignation initDesignation, Method cleanupMethod, Object obj) {
            this.initMethod = initMethod;
            this.initDesignation = initDesignation;
            this.cleanupMethod = cleanupMethod;
            this.obj = obj;
        }
        @Override
        public String toString() {
            return String.format("%s %s %s %s",
                    obj.getClass().getSimpleName(),
                    initMethod != null ? initMethod.getName() : "no init method",
                    initDesignation != null ? initDesignation.toString() : "no init designation",
                    cleanupMethod != null ? cleanupMethod.getName() : "no cleanup method");
        }
    }
}