package com.destroystokyo.paper.antixray;

import io.netty.buffer.ByteBuf;

public class DataBitsWriter {

    private ByteBuf dataBits; // Akarin
    private int bitsPerValue;
    private long mask;
    private int longInDataBitsIndex;
    private int bitInLongIndex;
    private long current;
    private boolean dirty;

    public void setDataBits(ByteBuf dataBits) { // Akarin
        this.dataBits = dataBits;
    }

    public void setBitsPerValue(int bitsPerValue) {
        this.bitsPerValue = bitsPerValue;
        mask = (1 << bitsPerValue) - 1;
    }

    public void setIndex(int index) {
        this.longInDataBitsIndex = index;
        bitInLongIndex = 0;
        init();
    }

    private void init() {
        if (dataBits.capacity() > longInDataBitsIndex + 7) { // Akarin
            // Akarin start
            current = dataBits.getLong(longInDataBitsIndex);
            /*
            current = ((((long) dataBits[longInDataBitsIndex]) << 56)
                    | (((long) dataBits[longInDataBitsIndex + 1] & 0xff) << 48)
                    | (((long) dataBits[longInDataBitsIndex + 2] & 0xff) << 40)
                    | (((long) dataBits[longInDataBitsIndex + 3] & 0xff) << 32)
                    | (((long) dataBits[longInDataBitsIndex + 4] & 0xff) << 24)
                    | (((long) dataBits[longInDataBitsIndex + 5] & 0xff) << 16)
                    | (((long) dataBits[longInDataBitsIndex + 6] & 0xff) << 8)
                    | (((long) dataBits[longInDataBitsIndex + 7] & 0xff)));
            */ // Akarin end
        }

        dirty = false;
    }

    public void finish() {
        if (dirty && dataBits.capacity() > longInDataBitsIndex + 7) { // Akarin
            // Akarin start
            dataBits.setLong(longInDataBitsIndex, current);
            /*
            dataBits[longInDataBitsIndex] = (byte) (current >> 56 & 0xff);
            dataBits[longInDataBitsIndex + 1] = (byte) (current >> 48 & 0xff);
            dataBits[longInDataBitsIndex + 2] = (byte) (current >> 40 & 0xff);
            dataBits[longInDataBitsIndex + 3] = (byte) (current >> 32 & 0xff);
            dataBits[longInDataBitsIndex + 4] = (byte) (current >> 24 & 0xff);
            dataBits[longInDataBitsIndex + 5] = (byte) (current >> 16 & 0xff);
            dataBits[longInDataBitsIndex + 6] = (byte) (current >> 8 & 0xff);
            dataBits[longInDataBitsIndex + 7] = (byte) (current & 0xff);
            */ // Akarin end
        }
    }

    public void write(int value) {
        current = current & ~(mask << bitInLongIndex) | (value & mask) << bitInLongIndex;
        dirty = true;
        bitInLongIndex += bitsPerValue;

        if (bitInLongIndex > 63) {
            finish();
            bitInLongIndex -= 64;
            longInDataBitsIndex += 8;
            init();

            if (bitInLongIndex > 0) {
                current = current & ~(mask >>> bitsPerValue - bitInLongIndex) | (value & mask) >>> bitsPerValue - bitInLongIndex;
                dirty = true;
            }
        }
    }

    public void skip() {
        bitInLongIndex += bitsPerValue;

        if (bitInLongIndex > 63) {
            finish();
            bitInLongIndex -= 64;
            longInDataBitsIndex += 8;
            init();
        }
    }
}