Copyright (c) 2008, http://www.snakeyaml.org
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.
/**
 * Copyright (c) 2008, http://www.snakeyaml.org
 *
 * 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.yaml.snakeyaml.introspector;

import java.lang.annotation.Annotation;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.yaml.snakeyaml.error.YAMLException;

// TODO: decide priorities for get/set Read/Field/Delegate Write/Field/Delegate - is FIELD on the correct place ?
public class PropertySubstitute extends Property {

    final private static Logger log = Logger.getLogger(PropertySubstitute.class.getPackage()
            .getName());

    protected Class<?> targetType;
    private final String readMethod;
    private final String writeMethod;
    transient private Method read;
    transient private Method write;
    private Field field;
    protected Class<?>[] parameters;
    private Property delegate;
    private boolean filler;

    public PropertySubstitute(String name, Class<?> type, String readMethod, String writeMethod,
            Class<?>... params) {
        super(name, type);
        this.readMethod = readMethod;
        this.writeMethod = writeMethod;
        setActualTypeArguments(params);
        this.filler = false;
    }

    public PropertySubstitute(String name, Class<?> type, Class<?>... params) {
        this(name, type, null, null, params);
    }

    @Override
    public Class<?>[] getActualTypeArguments() {
        if (parameters == null && delegate != null) {
            return delegate.getActualTypeArguments();
        }
        return parameters;
    }

    public void setActualTypeArguments(Class<?>... args) {
        if (args != null && args.length > 0) {
            parameters = args;
        } else {
            parameters = null;
        }
    }

    @Override
    public void set(Object object, Object value) throws Exception {
        if (write != null) {
            if (!filler) {
                write.invoke(object, value);
            } else if (value != null) {
                if (value instanceof Collection<?>) {
                    Collection<?> collection = (Collection<?>) value;
                    for (Object val : collection) {
                        write.invoke(object, val);
                    }
                } else if (value instanceof Map<?, ?>) {
                    Map<?, ?> map = (Map<?, ?>) value;
                    for (Entry<?, ?> entry : map.entrySet()) {
                        write.invoke(object, entry.getKey(), entry.getValue());
                    }
                } else if (value.getClass().isArray()) { // TODO: maybe arrays
                                                         // need 2 fillers like
                                                         // SET(index, value)
                                                         // add ADD(value)
                    int len = Array.getLength(value);
                    for (int i = 0; i < len; i++) {
                        write.invoke(object, Array.get(value, i));
                    }
                }
            }
        } else if (field != null) {
            field.set(object, value);
        } else if (delegate != null) {
            delegate.set(object, value);
        } else {
            log.warning("No setter/delegate for '" + getName() + "' on object " + object);
        }
        // TODO: maybe throw YAMLException here
    }

    @Override
    public Object get(Object object) {
        try {
            if (read != null) {
                return read.invoke(object);
            } else if (field != null) {
                return field.get(object);
            }
        } catch (Exception e) {
            throw new YAMLException("Unable to find getter for property '" + getName()
                    + "' on object " + object + ":" + e);
        }

        if (delegate != null) {
            return delegate.get(object);
        }
        throw new YAMLException("No getter or delegate for property '" + getName() + "' on object "
                + object);
    }

    @Override
    public List<Annotation> getAnnotations() {
        Annotation[] annotations = null;
        if (read != null) {
            annotations = read.getAnnotations();
        } else if (field != null) {
            annotations = field.getAnnotations();
        }
        return annotations != null ? Arrays.asList(annotations) : delegate.getAnnotations();
    }

    @Override
    public <A extends Annotation> A getAnnotation(Class<A> annotationType) {
        A annotation;
        if (read != null) {
            annotation = read.getAnnotation(annotationType);
        } else if (field != null) {
            annotation = field.getAnnotation(annotationType);
        } else {
            annotation = delegate.getAnnotation(annotationType);
        }
        return annotation;
    }

    public void setTargetType(Class<?> targetType) {
        if (this.targetType != targetType) {
            this.targetType = targetType;

            final String name = getName();
            for (Class<?> c = targetType; c != null; c = c.getSuperclass()) {
                for (Field f : c.getDeclaredFields()) {
                    if (f.getName().equals(name)) {
                        int modifiers = f.getModifiers();
                        if (!Modifier.isStatic(modifiers) && !Modifier.isTransient(modifiers)) {
                            f.setAccessible(true);
                            field = f;
                        }
                        break;
                    }
                }
            }
            if (field == null && log.isLoggable(Level.FINE)) {
                log.fine(String.format("Failed to find field for %s.%s", targetType.getName(),
                        getName()));
            }

            // Retrieve needed info
            if (readMethod != null) {
                read = discoverMethod(targetType, readMethod);
            }
            if (writeMethod != null) {
                filler = false;
                write = discoverMethod(targetType, writeMethod, getType());
                if (write == null && parameters != null) {
                    filler = true;
                    write = discoverMethod(targetType, writeMethod, parameters);
                }
            }
        }
    }

    private Method discoverMethod(Class<?> type, String name, Class<?>... params) {
        for (Class<?> c = type; c != null; c = c.getSuperclass()) {
            for (Method method : c.getDeclaredMethods()) {
                if (name.equals(method.getName())) {
                    Class<?>[] parameterTypes = method.getParameterTypes();
                    if (parameterTypes.length != params.length) {
                        continue;
                    }
                    boolean found = true;
                    for (int i = 0; i < parameterTypes.length; i++) {
                        if (!parameterTypes[i].isAssignableFrom(params[i])) {
                            found = false;
                        }
                    }
                    if (found) {
                        method.setAccessible(true);
                        return method;
                    }
                }
            }
        }
        if (log.isLoggable(Level.FINE)) {
            log.fine(String.format("Failed to find [%s(%d args)] for %s.%s", name, params.length,
                    targetType.getName(), getName()));
        }
        return null;
    }

    @Override
    public String getName() {
        final String n = super.getName();
        if (n != null) {
            return n;
        }
        return delegate != null ? delegate.getName() : null;
    }

    @Override
    public Class<?> getType() {
        final Class<?> t = super.getType();
        if (t != null) {
            return t;
        }
        return delegate != null ? delegate.getType() : null;
    }

    @Override
    public boolean isReadable() {
        return (read != null) || (field != null) || (delegate != null && delegate.isReadable());
    }

    @Override
    public boolean isWritable() {
        return (write != null) || (field != null) || (delegate != null && delegate.isWritable());
    }

    public void setDelegate(Property delegate) {
        this.delegate = delegate;
        if (writeMethod != null && write == null && !filler) {
            filler = true;
            write = discoverMethod(targetType, writeMethod, getActualTypeArguments());
        }
    }
}