/*******************************************************************************
 * 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
 *******************************************************************************/
package org.simantics.browsing.ui.swt;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.eclipse.core.runtime.IAdaptable;
import org.simantics.db.layer0.SelectionHints;
import org.simantics.ui.selection.WorkbenchSelectionContentType;
import org.simantics.ui.selection.WorkbenchSelectionElement;
import org.simantics.utils.ObjectUtils;
import org.simantics.utils.datastructures.hints.IHintContext;
import org.simantics.utils.datastructures.hints.IHintListener;
import org.simantics.utils.threads.IThreadWorkQueue;

/**
 * A custom internal hint context implementation that does not support
 * notifications to achieve a more space-optimized implementation.
 * 
 * @author Tuukka Lehtonen
 */
public class AdaptableHintContext implements IHintContext, IAdaptable, WorkbenchSelectionElement {

    private final Key[]              keysToTry;
    protected final Map<Key, Object> hints;

    public AdaptableHintContext() {
        this(SelectionHints.STD_KEYS);
    }

    public AdaptableHintContext(Key... keys) {
        this(new HashMap<Key, Object>(4), keys);
    }

    public AdaptableHintContext(Map<Key, Object> hints, Key... keys) {
        if (hints == null)
            throw new NullPointerException("null hints");
        this.keysToTry = keys;
        this.hints = hints;
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    @Override
    public Object getAdapter(Class adapter) {
        for (Key key : keysToTry) {
            Object o = getHint(key);
            if (adapter.isAssignableFrom(o.getClass()))
                return o;
            if (o instanceof IAdaptable) {
                Object adapted = ((IAdaptable) o).getAdapter(adapter);
                if (adapted != null) {
                    return adapted;
                }
            }
        }
        return null;
    }

    @Override
    public String toString() {
        return super.toString() + getHints();
    }

    @Override
    public void clearWithoutNotification() {
        hints.clear();
    }

    @Override
    public boolean containsHint(Key key) {
        return hints.get(key) != null;
    }

    @SuppressWarnings("unchecked")
    @Override
    public <E> E getHint(Key key) {
        if (key == null)
            throw new IllegalArgumentException("key is null");
        synchronized (this) {
            return (E) hints.get(key);
        }
    }

    @Override
    public synchronized Map<Key, Object> getHints() {
        return new HashMap<Key, Object>(hints);
    }

    @Override
    public Map<Key, Object> getHintsUnsafe() {
        return hints;
    }

    @SuppressWarnings("unchecked")
    @Override
    public <E extends Key> Map<E, Object> getHintsOfClass(Class<E> clazz) {
        Map<E, Object> result = null;
        for (Entry<Key, Object> e : hints.entrySet()) {
            Key key = e.getKey();
            if (clazz.isAssignableFrom(key.getClass())) {
                if (result == null)
                    result = new HashMap<E, Object>(4);
                result.put((E) key, e.getValue());
            }
        }
        return result;
    }

    @Override
    public void setHint(Key key, Object value) {
        if (key == null)
            throw new IllegalArgumentException("key is null");
        if (value == null)
            throw new IllegalArgumentException("value is null");
        if (!key.isValueAccepted(value))
            throw new RuntimeException("Value \"" + value + "\" is not accepted with key " + key.getClass().getName());

        synchronized (this) {
            hints.put(key, value);
        }
    }

    @Override
    public void setHints(Map<Key, Object> hints) {
        synchronized (this) {
            for (Entry<Key, Object> e : hints.entrySet()) {
                Key key = e.getKey();
                Object value = e.getValue();
                if (value == null)
                    throw new IllegalArgumentException("a value is null for key " + e.getKey());
                this.hints.put(key, value);
            }
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public <E> E removeHint(Key key) {
        if (key == null)
            throw new IllegalArgumentException("key is null");

        Object oldValue = null;
        synchronized (this) {
            oldValue = hints.remove(key);
        }
        if (oldValue == null)
            return null;
        return (E) oldValue;
    }

    @Override
    public void addHintListener(IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void removeHintListener(IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void addKeyHintListener(Key key, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void removeKeyHintListener(Key key, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void addHintListener(IThreadWorkQueue threadAccess, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void removeHintListener(IThreadWorkQueue threadAccess, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void addKeyHintListener(IThreadWorkQueue threadAccess, Key key, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public void removeKeyHintListener(IThreadWorkQueue threadAccess, Key key, IHintListener listener) {
        throw new UnsupportedOperationException();
    }

    @Override
    public int hashCode() {
        return ((hints.hashCode() * 31) + Arrays.hashCode(keysToTry)) * 31;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        AdaptableHintContext other = (AdaptableHintContext) obj;
        return Arrays.equals(keysToTry, other.keysToTry) && ObjectUtils.objectEquals(hints, other.hints);
    }

	@Override
	public <T> T getContent(WorkbenchSelectionContentType<T> contentType) {
		return null;
	}

}