/*
 * 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 OCamlString} class is the wrapper class for OCaml values of
 * type {@code string}.
 *
 * @author <a href="mailto:xclerc@ocamljava.org">Xavier Clerc</a>
 * @version 2.0
 * @since 2.0
 */
public final class OCamlString extends OCamlValue implements CharSequence {

    /** Wrapper for {@code OCamlString} values. */
    public static final Wrapper<OCamlString> WRAPPER = new SimpleWrapper<OCamlString>() {

        /**
         * {@inheritDoc}
         */
        @Override
        public OCamlString wrap(final Value v) {
            return new OCamlString(v);
        } // end method 'wrap(Value)'

    }; // end anonymous inner-class

    /**
     * Constructs a new instance wrapping the passed value.
     * @param v value to wrap - should not be {@code null}
     */
    private OCamlString(final Value v) {
        super(v);
    } // end constructor(Value)

    /**
     * {@inheritDoc}
     */
    @Override
    public Wrapper<? extends OCamlString> getWrapper() {
        return OCamlString.WRAPPER;
    } // end method 'getWrapper()'

    /**
     * {@inheritDoc}
     */
    @Override
    public Wrapper<? extends OCamlValue> getWrapper(final int idx) {
        return OCamlUnit.WRAPPER;
    } // end method 'getWrapper(int)'

    /**
     * Returns the wrapped value as a {@code String}.
     * @return the wrapped value, converted to a {@code String}
     */
    public String stringValue() {
        return this.value.asString();
    } // end method 'stringValue()'

    /**
     * Returns the {@code byte} value at the specified index.
     * @param idx index of {@code byte} value
     * @return the {@code byte} value at the specified index
     */
    public byte byteAt(final int idx) {
        return this.value.getByte(idx);
    } // end method 'byteAt(int)'

    /**
     * {@inheritDoc}
     */
    @Override
    public char charAt(final int idx) {
        return (char) this.value.getUnsignedByte(idx);
    } // end method 'charAt(int)'

    /**
     * Changes the {@code byte} value at the specified index.
     * @param idx index of {@code byte} value to modify
     * @param b new value
     */
    public void setByteAt(final int idx, final byte b) {
        this.value.setByte(idx, b);
    } // end method 'setByteAt(int, byte)'

    /**
     * Changes the {@code char} value at the specified index.
     * @param idx index of {@code char} value to modify
     * @param c new value
     */
    public void setCharAt(final int idx, final char c) {
        this.value.setUnsignedByte(idx, c);
    } // end method 'setCharAt(int)'

    /**
     * {@inheritDoc}
     */
    @Override
    public int length() {
        return (int) this.value.sizeBytes();
    } // end method 'length()'

    /**
     * {@inheritDoc}
     */
    @Override
    public CharSequence subSequence(final int start, final int end) {
        return this.value.asString().subSequence(start, end);
    } // end method 'subSequence(int, int)'

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode() {
        return this.value.asString().hashCode(); // XXX Value.hashBytes() ?
    } // end method 'hashCode()'

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals(final Object obj) {
        if (obj instanceof OCamlString) {
            final OCamlString that = (OCamlString) obj;
            return this.value.asString().equals(that.value.asString()); // XXX Value.equalStrings(-) ?
        } else {
            return false;
        } // end if/else
    } // end method 'equals(Object)'

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append("OCamlString(");
        sb.append(this.value.asString());
        sb.append(")");
        return sb.toString();
    } // end method 'toString()'

    /**
     * Constructs a new {@code string} value, and wraps it.
     * @param v value to wrap
     * @return a new {@code OCamlString} instance wrapping the passed value
     */
    public static OCamlString create(final String v) {
        return new OCamlString(Value.createString(v));
    } // end method 'create(String)'

    /**
     * Wraps the passed value.
     * @param v value to wrap - should not be {@code null}
     * @return a new {@code OCamlString} instance wrapping the passed value
     */
    public static OCamlString wrap(final Value v) {
        assert v != null : "null v";
        return new OCamlString(v);
    } // end method 'wrap(Value)'

    /**
     * Returns a wrapper for {@code OCamlString} values.
     * @return a wrapper for {@code OCamlString} values
     */
    public static Wrapper<? extends OCamlString> wrapper() {
        return OCamlString.WRAPPER;
    } // end method 'wrapper()'

} // end class 'OCamlString'