package codechicken.lib.asm;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import org.objectweb.asm.tree.ClassNode;

import cpw.mods.fml.common.asm.transformers.deobf.FMLDeobfuscatingRemapper;

import net.minecraft.launchwrapper.IClassTransformer;
import net.minecraft.launchwrapper.LaunchClassLoader;

/**
 * This is added as a class transformer if CodeChickenCore is installed. Adding it as a class transformer will speed evaluation up slightly by automatically caching superclasses when they are first loaded.
 */
public class ClassHeirachyManager implements IClassTransformer
{
    public static class SuperCache
    {
        String superclass;
        public HashSet<String> parents = new HashSet<String>();
        private boolean flattened;
        
        public void add(String parent)
        {
            parents.add(parent);
        }
        
        public void flatten()
        {
            if(flattened)
                return;
            
            for(String s : new ArrayList<String>(parents))
            {
                SuperCache c = declareClass(s);
                if(c != null)
                {
                    c.flatten();
                    parents.addAll(c.parents);
                }
            }
            flattened = true;
        }
    }
    
    public static HashMap<String, SuperCache> superclasses = new HashMap<String, SuperCache>();
    private static LaunchClassLoader cl = (LaunchClassLoader)ClassHeirachyManager.class.getClassLoader();
    
    static
    {
        cl.addTransformerExclusion("codechicken.lib.asm");
    }
    
    public static String toKey(String name)
    {
        if(ObfMapping.obfuscated)
            name = FMLDeobfuscatingRemapper.INSTANCE.map(name.replace('.', '/')).replace('/', '.');
        return name;
    }
    
    public static String unKey(String name)
    {
        if(ObfMapping.obfuscated)
            name = FMLDeobfuscatingRemapper.INSTANCE.unmap(name.replace('.', '/')).replace('/', '.');
        return name;
    }
    
    /**
     * Returns true if clazz extends, either directly or indirectly, superclass.
     * @param name The class in question
     * @param superclass The class being extended
     * @param bytes The bytes for the class. Only needed if not already defined.
     * @return
     */
    public static boolean classExtends(String name, String superclass)
    {
        name = toKey(name);
        superclass = toKey(superclass);
        
        if(name.equals(superclass))
            return true;
        
        SuperCache cache = declareClass(name);
        if(cache == null)//just can't handle this
            return false;
        
        cache.flatten();
        return cache.parents.contains(superclass);
    }

    private static SuperCache declareClass(String name) 
    {
        name = toKey(name);
        SuperCache cache = superclasses.get(name);
        
        if(cache != null)
            return cache;
        
        try
        {
            byte[] bytes = cl.getClassBytes(unKey(name));
            if(bytes != null)
                cache = declareASM(bytes);
        }
        catch(Exception e)
        {
        }

        if(cache != null)
            return cache;

        
        try
        {
            cache = declareReflection(name);
        }
        catch(ClassNotFoundException e)
        {
        }
        
        return cache;
    }

    private static SuperCache declareReflection(String name) throws ClassNotFoundException
    {
        Class<?> aclass = Class.forName(name);
        
        SuperCache cache = getOrCreateCache(name);
        if(aclass.isInterface())
            cache.superclass = "java.lang.Object";
        else if(name.equals("java.lang.Object"))
            return cache;
        else
            cache.superclass = toKey(aclass.getSuperclass().getName());
        
        cache.add(cache.superclass);
        for(Class<?> iclass : aclass.getInterfaces())
            cache.add(toKey(iclass.getName()));
        
        return cache;
    }

    private static SuperCache declareASM(byte[] bytes)
    {
        ClassNode node = ASMHelper.createClassNode(bytes);
        String name = toKey(node.name);
        
        SuperCache cache = getOrCreateCache(name);
        cache.superclass = toKey(node.superName.replace('/', '.'));
        cache.add(cache.superclass);
        for(String iclass : node.interfaces)
            cache.add(toKey(iclass.replace('/', '.')));
        
        return cache;
    }

    @Override
    public byte[] transform(String name, String tname, byte[] bytes)
    {
        if (bytes == null)
            return null;
        
        if(!superclasses.containsKey(tname))
            declareASM(bytes);
        
        return bytes;
    }
    
    public static SuperCache getOrCreateCache(String name)
    {
        SuperCache cache = superclasses.get(name);
        if(cache == null)
            superclasses.put(name, cache = new SuperCache());
        return cache;
    }

    public static String getSuperClass(String name, boolean runtime) 
    {
        name = toKey(name);
        SuperCache cache = declareClass(name);
        if(cache == null)
            return "java.lang.Object";
        
        cache.flatten();
        String s = cache.superclass;
        if(!runtime)
            s = FMLDeobfuscatingRemapper.INSTANCE.unmap(s);
        return s;
    }
}