package com.sk89q.jnbt;

import java.io.Closeable;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import java.util.zip.GZIPOutputStream;
import com.sk89q.jnbt.ByteArrayTag;
import com.sk89q.jnbt.ByteTag;
import com.sk89q.jnbt.CompoundTag;
import com.sk89q.jnbt.DoubleTag;
import com.sk89q.jnbt.EndTag;
import com.sk89q.jnbt.FloatTag;
import com.sk89q.jnbt.IntTag;
import com.sk89q.jnbt.ListTag;
import com.sk89q.jnbt.LongTag;
import com.sk89q.jnbt.NBTConstants;
import com.sk89q.jnbt.NBTUtils;
import com.sk89q.jnbt.ShortTag;
import com.sk89q.jnbt.StringTag;
import com.sk89q.jnbt.Tag;

/*
 * JNBT License
 * 
 * Copyright (c) 2010 Graham Edgecombe
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *       
 *     * 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.
 *       
 *     * Neither the name of the JNBT team nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 * 
 * 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. 
 */

/**
 * <p>
 * This class writes <strong>NBT</strong>, or <strong>Named Binary Tag</strong>
 * <code>Tag</code> objects to an underlying <code>OutputStream</code>.
 * </p>
 * 
 * <p>
 * The NBT format was created by Markus Persson, and the specification may be
 * found at <a href="http://www.minecraft.net/docs/NBT.txt">
 * http://www.minecraft.net/docs/NBT.txt</a>.
 * </p>
 * 
 * @author Graham Edgecombe
 * 
 */
public final class NBTOutputStream implements Closeable {

    /**
     * The output stream.
     */
    private final DataOutputStream os;

    /**
     * Creates a new <code>NBTOutputStream</code>, which will write data to the
     * specified underlying output stream.
     * 
     * @param os
     *            The output stream.
     * @throws IOException
     *             if an I/O error occurs.
     */
    public NBTOutputStream(OutputStream os) throws IOException {
        this.os = new DataOutputStream(new GZIPOutputStream(os));
    }

    /**
     * Writes a tag.
     * 
     * @param tag
     *            The tag to write.
     * @throws IOException
     *             if an I/O error occurs.
     */
    public void writeTag(Tag tag) throws IOException {
        int type = NBTUtils.getTypeCode(tag.getClass());
        String name = tag.getName();
        byte[] nameBytes = name.getBytes(NBTConstants.CHARSET);

        os.writeByte(type);
        os.writeShort(nameBytes.length);
        os.write(nameBytes);

        if (type == NBTConstants.TYPE_END) {
            throw new IOException("Named TAG_End not permitted.");
        }

        writeTagPayload(tag);
    }

    /**
     * Writes tag payload.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeTagPayload(Tag tag) throws IOException {
        int type = NBTUtils.getTypeCode(tag.getClass());
        switch (type) {
        case NBTConstants.TYPE_END:
            writeEndTagPayload((EndTag) tag);
            break;
        case NBTConstants.TYPE_BYTE:
            writeByteTagPayload((ByteTag) tag);
            break;
        case NBTConstants.TYPE_SHORT:
            writeShortTagPayload((ShortTag) tag);
            break;
        case NBTConstants.TYPE_INT:
            writeIntTagPayload((IntTag) tag);
            break;
        case NBTConstants.TYPE_LONG:
            writeLongTagPayload((LongTag) tag);
            break;
        case NBTConstants.TYPE_FLOAT:
            writeFloatTagPayload((FloatTag) tag);
            break;
        case NBTConstants.TYPE_DOUBLE:
            writeDoubleTagPayload((DoubleTag) tag);
            break;
        case NBTConstants.TYPE_BYTE_ARRAY:
            writeByteArrayTagPayload((ByteArrayTag) tag);
            break;
        case NBTConstants.TYPE_STRING:
            writeStringTagPayload((StringTag) tag);
            break;
        case NBTConstants.TYPE_LIST:
            writeListTagPayload((ListTag) tag);
            break;
        case NBTConstants.TYPE_COMPOUND:
            writeCompoundTagPayload((CompoundTag) tag);
            break;
        default:
            throw new IOException("Invalid tag type: " + type + ".");
        }
    }

    /**
     * Writes a <code>TAG_Byte</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeByteTagPayload(ByteTag tag) throws IOException {
        os.writeByte(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Byte_Array</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeByteArrayTagPayload(ByteArrayTag tag) throws IOException {
        byte[] bytes = tag.getValue();
        os.writeInt(bytes.length);
        os.write(bytes);
    }

    /**
     * Writes a <code>TAG_Compound</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeCompoundTagPayload(CompoundTag tag) throws IOException {
        for (Tag childTag : tag.getValue().values()) {
            writeTag(childTag);
        }
        os.writeByte((byte) 0); // end tag - better way?
    }

    /**
     * Writes a <code>TAG_List</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeListTagPayload(ListTag tag) throws IOException {
        Class<? extends Tag> clazz = tag.getType();
        List<Tag> tags = tag.getValue();
        int size = tags.size();

        os.writeByte(NBTUtils.getTypeCode(clazz));
        os.writeInt(size);
        for (int i = 0; i < size; i++) {
            writeTagPayload(tags.get(i));
        }
    }

    /**
     * Writes a <code>TAG_String</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeStringTagPayload(StringTag tag) throws IOException {
        byte[] bytes = tag.getValue().getBytes(NBTConstants.CHARSET);
        os.writeShort(bytes.length);
        os.write(bytes);
    }

    /**
     * Writes a <code>TAG_Double</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeDoubleTagPayload(DoubleTag tag) throws IOException {
        os.writeDouble(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Float</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeFloatTagPayload(FloatTag tag) throws IOException {
        os.writeFloat(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Long</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeLongTagPayload(LongTag tag) throws IOException {
        os.writeLong(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Int</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeIntTagPayload(IntTag tag) throws IOException {
        os.writeInt(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Short</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeShortTagPayload(ShortTag tag) throws IOException {
        os.writeShort(tag.getValue());
    }

    /**
     * Writes a <code>TAG_Empty</code> tag.
     * 
     * @param tag
     *            The tag.
     * @throws IOException
     *             if an I/O error occurs.
     */
    private void writeEndTagPayload(EndTag tag) {
        /* empty */
    }

    public void close() throws IOException {
        os.close();
    }

}