/**
 * Copyright (c) 2014, University of Warsaw
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package pl.edu.mimuw.cloudatlas.model;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import pl.edu.mimuw.cloudatlas.model.TypeCollection;
import pl.edu.mimuw.cloudatlas.model.Value;
import pl.edu.mimuw.cloudatlas.model.ValueSet;

/**
 * A value representing a set of values of the specified type. Implements <code>Set</code> interface.
 * <p>
 * All constructors take a type of elements stored in this set. This type is checked when adding elements to the set and
 * an <code>IllegalArgumentException</code> is thrown in case of a mismatch.
 *
 * @see java.util.Set
 */
public class ValueSet extends ValueSimple<Set<Value>> implements Set<Value> {
    private TypeCollection type;

    /**
     * Creates a new <code>ValueSet</code> containing all the elements in the specified set.
     *
     * @param value a set which content will be copied to this value
     * @param elementType type of elements stored in this set
     */
    public ValueSet(Set<Value> value, Type elementType) {
        this(elementType);
        if(value != null)
            setValue(value);
    }

    /* Kryo needs a no-args constructor */
    private ValueSet() {
    }

    /**
     * Creates an empty set.
     *
     * @param elementType type of elements stored in this set
     */
    public ValueSet(Type elementType) {
        super(new HashSet<Value>());
        type = new TypeCollection(Type.PrimaryType.SET, elementType);
    }

    @Override
    public Type getType() {
        return type;
    }

    @Override
    public Value getDefaultValue() {
        return new ValueSet(((TypeCollection)this.getType()).getElementType());
    }

    /**
     * Gets a <code>Set</code> containing all the objects stored in this value. Modifying the returned list will cause an
     * exception.
     */
    @Override
    public Set<Value> getValue() {
        return getSet() == null? null : Collections.unmodifiableSet(getSet());
    }

    @Override
    public ValueSet addValue(Value value) {
        sameTypesOrThrow(value, Operation.ADD);
        if(isNull() || value.isNull())
            return new ValueSet(null, ((TypeCollection)getType()).getElementType());
        Set<Value> result = new HashSet<Value>(getValue());
        result.addAll(((ValueSet)value).getValue());
        return new ValueSet(result, ((TypeCollection)getType()).getElementType());
    }

    @Override
    public ValueInt valueSize() {
        return new ValueInt((getSet() == null? null : (long)getSet().size()));
    }

    @Override
    public void setValue(Set<Value> set) {
        if(set == null)
            super.setValue(null);
        else {
            super.setValue(new HashSet<Value>());
            for(Value e : set)
                add(e);
        }
    }

    private Set<Value> getSet() {
        return super.getValue();
    }

    private void checkElement(Value element) {
        if(element == null)
            throw new IllegalArgumentException("If you want to use null, create an object containing null instead.");
        if(!type.getElementType().isCompatible(element.getType()))
            throw new IllegalArgumentException("This set contains elements of type " + type.getElementType().toString()
                    + " only. Incompatible with elements of type: " + element.getType().toString());
    }

    @Override
    public boolean add(Value e) {
        checkElement(e);
        return getSet().add(e);
    }

    @Override
    public boolean addAll(Collection<? extends Value> c) {
        for(Value e : c)
            checkElement(e);
        return getSet().addAll(c);
    }

    @Override
    public void clear() {
        getSet().clear();
    }

    @Override
    public boolean contains(Object o) {
        return getSet().contains(o);
    }

    @Override
    public boolean containsAll(Collection<?> c) {
        return getSet().containsAll(c);
    }

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

    @Override
    public Iterator<Value> iterator() {
        return getSet().iterator();
    }

    @Override
    public boolean remove(Object o) {
        return getSet().remove(o);
    }

    @Override
    public boolean removeAll(Collection<?> c) {
        return getSet().removeAll(c);
    }

    @Override
    public boolean retainAll(Collection<?> c) {
        return getSet().retainAll(c);
    }

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

    @Override
    public Object[] toArray() {
        return getSet().toArray();
    }

    @Override
    public <U> U[] toArray(U[] a) {
        return getSet().toArray(a);
    }

    @Override
    public Value convertTo(Type type) {
        switch(type.getPrimaryType()) {
            case SET:
                if(getType().isCompatible(type))
                    return this;
                throw new UnsupportedConversionException(getType(), type);
            case LIST:
                if(this.type.getElementType().isCompatible(((TypeCollection)type).getElementType())) {
                    if(this.isNull())
                        return new ValueList(null, this.type.getElementType());
                    List<Value> list = new ArrayList<Value>();
                    list.addAll(this);
                    return new ValueList(list, this.type.getElementType());
                }
                throw new UnsupportedConversionException(getType(), type);
            case STRING:
                if(getValue() == null)
                    return ValueString.NULL_STRING;
                StringBuilder sb = new StringBuilder();
                sb.append("{");
                boolean notFirst = false;
                for(Value v : getValue()) {
                    if(notFirst) {
                        sb.append(", ");
                    } else
                        notFirst = true;
                    sb.append(v.toString());
                }
                sb.append("}");
                return new ValueString(sb.toString());
            default:
                throw new UnsupportedConversionException(getType(), type);
        }
    }
}