package speiger.src.coreengine.assets.impl;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import speiger.src.coreengine.assets.AssetLocation;
import speiger.src.coreengine.assets.IAsset;
import speiger.src.coreengine.assets.IAssetPackage;
import speiger.src.coreengine.utils.collections.iterators.IterableWrapper;

public class ZipAssetPackage implements IAssetPackage
{
	public static final int ASSET_OFFSET = "assets/".length();
	File file;
	ZipFile cache = null;
	AtomicInteger usedReferences = new AtomicInteger();
	
	public ZipAssetPackage(File file)
	{
		this.file = file;
	}
	
	protected ZipFile getReference() throws IOException
	{
		usedReferences.getAndIncrement();
		if(cache == null) cache = new ZipFile(file);
		return cache;
	}
	
	protected void onReferenceClosed()
	{
		int left = usedReferences.decrementAndGet();
		if(left == 0 && cache != null)
		{
			try
			{
				cache.close();
			}
			catch(Exception e) {e.printStackTrace();}
			cache = null;
		}
		else if(left < 0)
		{
			usedReferences.set(0);
		}
	}
	
	@Override
	public List<String> getDomains()
	{
		try
		{
			List<String> result = new ArrayList<String>();
			ZipFile zip = new ZipFile(file);
			for(ZipEntry entry : IterableWrapper.wrap(zip.entries()))
			{
				String name = entry.getName();
				if(isPathValid(name))
				{
					result.add(name.substring(ASSET_OFFSET, name.length() - 1));
				}
			}
			zip.close();
			return result;
		}
		catch(IOException e)
		{
			e.printStackTrace();
			return Collections.emptyList();
		}
	}
	
	private boolean isPathValid(String input)
	{
		if(input.startsWith("assets/"))
		{
			int index = input.indexOf("/", ASSET_OFFSET);
			if(index != -1 && input.length() - index <= 1)
			{
				return true;
			}
		}
		return false; 
	}
	
	@Override
	public IAsset getAsset(AssetLocation location)
	{
		try
		{
			ZipFile zip = getReference();
			ZipEntry entry = zip.getEntry(location.getActualLocation());
			if(entry != null)
			{
				return new ZipAsset(zip, entry, location, this::onReferenceClosed);
			}
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		onReferenceClosed();
		return null;
	}
}