package org.bukkit.craftbukkit.util;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.BitSet;

import net.minecraft.server.Chunk;

public class TickQueue {
    public BitSet blockCache = new BitSet(32768);
    public BitSet columnCache = new BitSet(256);
    public LongHeap heap = new LongHeap();

    /**
     * Each long has on the inside:
     * 32bit time
     *  1bit isColumn
     *  4bit x
     *  4bit z
     *  7bit y
     * 16bit data
     */

    public synchronized void insert(long entry) {
        int coord = (int) ((entry >> 16) & 0xFFFF);

        BitSet cache = blockCache;
        int cacheEntry = coord & 0x7FFF;

        // isColumn
        if (((entry >> 31) & 0x1) == 1) {
            cache = columnCache;
            cacheEntry = (coord >> 7) & 0xFF;
        }

        if (cache.get(cacheEntry)) {
            heap.removeByCoord(coord);
        } else {
            cache.set(cacheEntry);
        }

        heap.insert(entry);
    }

    public synchronized long pop() {
        long entry = heap.popHead();

        // isColumn
        if (((entry >> 31) & 0x1) == 1) {
            columnCache.clear((int) ((entry >> 7) & 0xFF));
        } else {
            blockCache.clear((int) ((entry >> 16) & 0x7FFF));
        }

        return entry;
    }

    public long peek() {
        if (heap.isEmpty()) return Long.MAX_VALUE;
        return heap.peekHead();
    }

    public void fromByteArray(byte[] data, boolean hasRestarted, int deltaTime) {
        long value;
        int newTime;
        ByteArrayInputStream bis = new ByteArrayInputStream(data);
        DataInputStream dis = new DataInputStream(bis);

        try {
            while(dis.available() > 0) {
                value = dis.readLong();
                newTime = (int) (value >>> 32);
                if (hasRestarted) {
                    newTime += deltaTime;
                    if (newTime < 0) newTime = 0;

                    value = (value & 0xFFFFFFFF) | (((long) newTime) << 32);
                }

                // Due to an early bug; only queue stuff that is supposed to happen within the next hour
                if (newTime < 20 * 60 * 60)
                    this.insert(value);
            }
        } catch (IOException e) {
            // yeah blah memory, i dont care.
        } finally {
            try {
                dis.close();
                bis.close();
            } catch (IOException e) {
            }
        }
    }

    public byte[] toByteArray() {
        return heap.toByteArray();
    }
}