/*
 * This file is part of OCaml-Java runtime.
 * Copyright (C) 2007-2013 Xavier Clerc.
 *
 * OCaml-Java runtime is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * OCaml-Java runtime is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.ocamljava.runtime.wrappers;

import org.ocamljava.runtime.values.Value;

/**
 * The {@code OCamlOption} class is the wrapper class for OCaml values of
 * type {@code 'a * 'b}.
 *
 * @author <a href="mailto:xclerc@ocamljava.org">Xavier Clerc</a>
 * @version 2.0
 * @since 2.0
 */
public final class OCamlTuple2<T0 extends OCamlValue,
                               T1 extends OCamlValue> extends OCamlValue {

    /** Wrapper for nested value. */
    private final Wrapper<T0> wrapper0;

    /** Wrapper for nested value. */
    private final Wrapper<T1> wrapper1;

    /**
     * Constructs a new instance wrapping the passed value.
     * @param w0 wrapper for nested value - should not be {@code null}
     * @param w1 wrapper for nested value - should not be {@code null}
     * @param v value to wrap - should not be {@code null}
     */
    private OCamlTuple2(final Wrapper<T0> w0,
                        final Wrapper<T1> w1,
                        final Value v) {
        super(v);
        assert w0 != null : "null w0";
        assert w1 != null : "null w1";
        this.wrapper0 = w0;
        this.wrapper1 = w1;
    } // end constructor(Wrapper<T0>, Wrapper<T1>, Value)

    /**
     * {@inheritDoc}
     */
    @Override
    public Wrapper<? extends OCamlTuple2<T0, T1>> getWrapper() {
        return OCamlTuple2.wrapper(this.wrapper0,
                                   this.wrapper1);
    } // end method 'getWrapper()'

    /**
     * {@inheritDoc}
     */
    @Override
    public Wrapper<? extends OCamlValue> getWrapper(final int idx) {
        switch (idx) {
        case 0: return this.wrapper0;
        case 1: return this.wrapper1;
        default: return OCamlUnit.WRAPPER;
        } // end switch
    } // end method 'getWrapper(int)'

    /**
     * Returns the first element of the wrapped value.
     * @return the first element of the wrapped value
     */
    public T0 get0() {
        return this.wrapper0.wrap(this.value.get0());
    } // end method 'get0()'

    /**
     * Returns the second element of the wrapped value.
     * @return the second element of the wrapped value
     */
    public T1 get1() {
        return this.wrapper1.wrap(this.value.get1());
    } // end method 'get1()'

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode() {
        return this.value.get0().hashCode()
            + this.value.get1().hashCode();
    } // end method 'hashCode()'

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals(final Object obj) {
        if (obj instanceof OCamlTuple2) {
            final OCamlTuple2<?, ?> that = (OCamlTuple2) obj;
            return this.value.get0().equals(that.value.get0())
                && this.value.get1().equals(that.value.get1());
        } else {
            return false;
        } // end if/else
    } // end method 'equals(Object)'

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append("OCamlTuple2(");
        sb.append(this.wrapper0.wrap(this.value.get0()).toString());
        sb.append(", ");
        sb.append(this.wrapper1.wrap(this.value.get1()).toString());
        sb.append(")");
        return sb.toString();
    } // end method 'toString()'

    /**
     * Constructs a new {@code 'a * 'b} value, and wraps it.
     * @param v0 first element of value to wrap - should not be {@code null}
     * @param v1 second element of value to wrap - should not be {@code null}
     * @return a new {@code OCamlTuple2} instance wrapping the passed values
     */
    @SuppressWarnings("unchecked")
    public static <T0 extends OCamlValue,
                   T1 extends OCamlValue>
        OCamlTuple2<T0, T1> create(final T0 v0,
                                   final T1 v1) {
        assert v0 != null : "null v0";
        assert v1 != null : "null v1";
        return new OCamlTuple2<T0, T1>((Wrapper<T0>) v0.getWrapper(),
                                       (Wrapper<T1>) v1.getWrapper(),
                                       Value.createBlock(0,
                                                         v0.value(),
                                                         v1.value()));
    } // end method 'create(T0, T1)'

    /**
     * Wraps the passed value.
     * @param w0 wrapper for nested value - should not be {@code null}
     * @param w1 wrapper for nested value - should not be {@code null}
     * @param v value to wrap - should not be {@code null}
     * @return a new {@code OCamlTuple2} instance wrapping the passed value
     */
    public static <T0 extends OCamlValue,
                   T1 extends OCamlValue>
        OCamlTuple2<T0, T1> wrap(final Wrapper<T0> w0,
                                 final Wrapper<T1> w1,
                                 final Value v) {
        assert w0 != null : "null w0";
        assert w1 != null : "null w1";
        assert v != null : "null v";
        return new OCamlTuple2<T0, T1>(w0, w1, v);
    } // end method 'wrap(Wrapper<T0>, Wrapper<T1>, Value)'

    /**
     * Returns a wrapper for {@code OCamlOption} values.
     * @param w0 wrapper for nested value - should not be {@code null}
     * @param w1 wrapper for nested value - should not be {@code null}
     * @return a wrapper for {@code OCamlOption} values
     */
    @SuppressWarnings("unchecked")
    public static <T0 extends OCamlValue,
                   T1 extends OCamlValue>
        Wrapper<? extends OCamlTuple2<T0, T1>> wrapper(final Wrapper<T0> w0,
                                                       final Wrapper<T1> w1) {
        return new ComposedWrapper<OCamlTuple2<T0, T1>>(w0, w1) {
            /**
             * {@inheritDoc}
             */
            @Override
                public OCamlTuple2<T0, T1> wrap(final Value v) {
                return new OCamlTuple2<T0, T1>(w0, w1, v);
            } // end method 'wrap(Value)'
        }; // end anonymous inner-class
    } // end method 'wrapper(Wrapper<T0>, Wrapper<T1>)'

} // end class 'OCamlTuple2'