/*

 *  Copyright 2009-present, Stephen Colebourne

 *

 *  Licensed under the Apache License, Version 2.0 (the "License");

 *  you may not use this file except in compliance with the License.

 *  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 *  Unless required by applicable law or agreed to in writing, software

 *  distributed under the License is distributed on an "AS IS" BASIS,

 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 *  See the License for the specific language governing permissions and

 *  limitations under the License.

 */

package org.joda.money;

import java.io.Externalizable;

import java.io.IOException;

import java.io.InvalidClassException;

import java.io.InvalidObjectException;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.io.StreamCorruptedException;

import java.math.BigDecimal;

import java.math.BigInteger;

/**

 * A package scoped class used to manage serialization efficiently.

 * <p>

 * This class is mutable and intended for use by a single thread.

 */

final class Ser implements Externalizable {

    /** Type for BigMoney. */

    static final byte BIG_MONEY = 'B';

    /** Type for Money. */

    static final byte MONEY = 'M';

    /** Type for CurrencyUnit. */

    static final byte CURRENCY_UNIT = 'C';  // not in use yet

    /** The type. */

    private byte type;

    /** The data object. */

    private Object object;

    /**

     * Constructor for serialization.

     */

    public Ser() {

    }

    /**

     * Constructor for package.

     *

     * @param type  the type

     * @param object  the object

     */

    Ser(byte type, Object object) {

        this.type = type;

        this.object = object;

    }

    //-----------------------------------------------------------------------

    /**

     * Outputs the data.

     *

     * @serialData One byte type code, then data specific to the type.

     * @param out  the output stream

     * @throws IOException if an error occurs

     */

    @Override

    public void writeExternal(ObjectOutput out) throws IOException {

        out.writeByte(type);

        switch (type) {

            case BIG_MONEY -> {

                var obj = (BigMoney) object;

                writeBigMoney(out, obj);

            }

            case MONEY -> {

                var obj = (Money) object;

                writeBigMoney(out, obj.toBigMoney());

            }

            case CURRENCY_UNIT -> {

                var obj = (CurrencyUnit) object;

                writeCurrency(out, obj);

            }

            default -> throw new InvalidClassException("Joda-Money bug: Serialization broken");

        }

    }

    private void writeBigMoney(ObjectOutput out, BigMoney obj) throws IOException {

        writeCurrency(out, obj.getCurrencyUnit());

        var bytes = obj.getAmount().unscaledValue().toByteArray();

        out.writeInt(bytes.length);

        out.write(bytes);

        out.writeInt(obj.getScale());

    }

    private void writeCurrency(ObjectOutput out, CurrencyUnit obj) throws IOException {

        out.writeUTF(obj.getCode());

        out.writeShort(obj.getNumericCode());

        out.writeShort(obj.getDecimalPlaces());

    }

    /**

     * Outputs the data.

     *

     * @param in  the input stream

     * @throws IOException if an error occurs

     */

    @Override

    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {

        type = in.readByte();

        switch (type) {

            case BIG_MONEY -> {

                object = readBigMoney(in);

            }

            case MONEY -> {

                object = new Money(readBigMoney(in));

            }

            case CURRENCY_UNIT -> {

                object = readCurrency(in);

            }

            default -> throw new StreamCorruptedException("Serialization input has invalid type");

        }

    }

    private BigMoney readBigMoney(ObjectInput in) throws IOException {

        var currency = readCurrency(in);

        var bytes = new byte[in.readInt()];

        in.readFully(bytes);

        var bd = new BigDecimal(new BigInteger(bytes), in.readInt());

        var bigMoney = new BigMoney(currency, bd);

        return bigMoney;

    }

    private CurrencyUnit readCurrency(ObjectInput in) throws IOException {

        var code = in.readUTF();

        var singletonCurrency = CurrencyUnit.of(code);

        if (singletonCurrency.getNumericCode() != in.readShort()) {

            throw new InvalidObjectException("Deserialization found a mismatch in the numeric code for currency " + code);

        }

        if (singletonCurrency.getDecimalPlaces() != in.readShort()) {

            throw new InvalidObjectException("Deserialization found a mismatch in the decimal places for currency " + code);

        }

        return singletonCurrency;

    }

    /**

     * Returns the object that will replace this one.

     *

     * @return the read object, should never be null

     */

    private Object readResolve() {

        return object;

    }

}