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package net.dongliu.commons.bean;

import net.dongliu.commons.collection.Iterators;
import net.dongliu.commons.collection.MoreCollections;
import net.dongliu.commons.collection.Pair;
import net.dongliu.commons.concurrent.WeakCache;
import net.dongliu.commons.exception.Throwables;

import javax.annotation.Nonnull;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.util.*;

/**
 * Wrap bean as immutable map
 *
 * @author Liu Dong
 */
class BeanMap implements Map {

    private final Object bean;
    private final Map map;

    private static final WeakCache, Map> cache =
            WeakCache.create(BeanMap::getPropertyMap);

    public BeanMap(Object bean) {
        this.bean = Objects.requireNonNull(bean);
        this.map = cache.get(bean.getClass());
    }

    @Nonnull
    private static Map getPropertyMap(Class cls) {
        Map map = new HashMap<>();
        for (PropertyDescriptor descriptor : Beans.getProperties(cls)) {
            if (descriptor.getReadMethod() != null) {
                String name = descriptor.getName();
                map.put(name, descriptor);
            }
        }
        return map;
    }

    @Override
    public int size() {
        return map.size();
    }

    @Override
    public boolean isEmpty() {
        return map.isEmpty();
    }

    @Override
    public boolean containsKey(Object key) {
        return map.containsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
        for (String key : map.keySet()) {
            PropertyDescriptor descriptor = map.get(key);
            Object v = getValue(descriptor);
            if (Objects.equals(value, v)) {
                return true;
            }
        }
        return false;
    }

    private Object getValue(PropertyDescriptor descriptor) {
        try {
            return descriptor.getReadMethod().invoke(bean);
        } catch (IllegalAccessException | InvocationTargetException e) {
            throw Throwables.throwAny(e);
        }
    }

    @Override
    public Object get(Object key) {
        PropertyDescriptor descriptor = map.get(key);
        if (descriptor == null) {
            return null;
        }
        return getValue(descriptor);
    }

    @Override
    public Object put(String key, Object value) {
        throw new UnsupportedOperationException();
    }

    @Override
    public Object remove(Object key) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void putAll(Map m) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void clear() {
        throw new UnsupportedOperationException();
    }

    @Override
    @Nonnull
    public Set keySet() {
        return map.keySet();
    }

    @Override
    @Nonnull
    public Collection