package example.com.velezguiatour;

import android.graphics.Bitmap;
import android.util.Log;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;

public class MemoryCache
{

    private static final String TAG = "MemoryCache";
    private Map<String, Bitmap> cache=Collections.synchronizedMap(
            new LinkedHashMap<String, Bitmap>(10,1.5f,true));//Last argument true for LRU ordering
    private long size=0;//current allocated size
    private long limit=1000000;//max memory in bytes

    public MemoryCache()
    {
        //use 25% of available heap size
        setLimit(Runtime.getRuntime().maxMemory()/4);
    }
    
    public void setLimit(long new_limit)
    {
        limit = new_limit;
        Log.i(TAG, "MemoryCache will use up to "+limit/1024./1024.+"MB");
    }

    public Bitmap get(String id)
    {
        try
        {
            if(!cache.containsKey(id))
            {
            	return null;
            }
            //NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
            return cache.get(id);
        }
        catch(NullPointerException ex)
        {
            ex.printStackTrace();
            return null;
        }
    }

    public void put(String id, Bitmap bitmap)
    {
        try
        {
            if(cache.containsKey(id))
            {
            	size-=getSizeInBytes(cache.get(id));
            }
            cache.put(id, bitmap);
            size+=getSizeInBytes(bitmap);
            checkSize();
        }
        catch(Throwable th)
        {
            th.printStackTrace();
        }
    }
    
    private void checkSize()
    {
        Log.i(TAG, "cache size="+size+" length="+cache.size());
        if(size>limit)
        {
            Iterator<Entry<String, Bitmap>> iter=cache.entrySet().iterator();//least recently accessed item will be the first one iterated  
            while(iter.hasNext())
            {
                Entry<String, Bitmap> entry=iter.next();
                size-=getSizeInBytes(entry.getValue());
                iter.remove();
                if(size <= limit)
                {
                	break;
                }
            }
            Log.i(TAG, "Clean cache. New size "+cache.size());
        }
    }

    public void clear()
    {
        try
        {
            //NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
            cache.clear();
            size = 0;
        }
        catch(NullPointerException ex)
        {
            ex.printStackTrace();
        }
    }

    long getSizeInBytes(Bitmap bitmap)
    {
        if(bitmap == null)
        {
        	return 0;
        }
        return bitmap.getRowBytes() * bitmap.getHeight();
    }

}