package luan.impl;

import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.HashMap;
import luan.LuanFunction;
import luan.LuanState;
import luan.LuanException;
import luan.LuanTable;
import luan.LuanJava;
import luan.modules.JavaLuan;
import luan.modules.PackageLuan;


public final class LuanCompiler {
	private static final Map<String,WeakReference<Class>> map = new HashMap<String,WeakReference<Class>>();

	public static LuanFunction compile(String sourceText,String sourceName,LuanTable env) throws LuanException {
		Class fnClass = env==null ? getClass(sourceText,sourceName) : getClass(sourceText,sourceName,env);
		LuanJava java;
		if( env == null ) {
			java = new LuanJava();
		} else {
			java = env.java;
			if( java == null ) {
				java = new LuanJava();
				env.java = java;
			}
		}
		Closure closure;
		try {
			closure = (Closure)fnClass.getConstructor(LuanJava.class).newInstance(java);
		} catch(NoSuchMethodException e) {
			throw new RuntimeException(e);
		} catch(InstantiationException e) {
			throw new RuntimeException(e);
		} catch(IllegalAccessException e) {
			throw new RuntimeException(e);
		} catch(InvocationTargetException e) {
			throw new RuntimeException(e);
		}
		closure.upValues[0].o = JavaLuan.javaFn;
		closure.upValues[1].o = PackageLuan.requireFn;
		if( env != null )  closure.upValues[2].o = env;
		return closure;
	}

	private static synchronized Class getClass(String sourceText,String sourceName) throws LuanException {
		String key = sourceName + "~~~" + sourceText;
		WeakReference<Class> ref = map.get(key);
		if( ref != null ) {
			Class cls = ref.get();
			if( cls != null )
				return cls;
		}
		Class cls = getClass(sourceText,sourceName,null);
		map.put(key,new WeakReference<Class>(cls));
		return cls;
	}

	private static Class getClass(String sourceText,String sourceName,LuanTable env) throws LuanException {
		LuanParser parser = new LuanParser(sourceText,sourceName);
		parser.addVar( "java" );
		parser.addVar( "require" );
		if( env != null )  parser.addVar( "_ENV" );
		try {
			return parser.RequiredModule();
		} catch(ParseException e) {
//e.printStackTrace();
			throw new LuanException( e.getFancyMessage() );
		}
	}

	public static String toJava(String sourceText,String sourceName) throws LuanException {
		LuanParser parser = new LuanParser(sourceText,sourceName);
		parser.addVar( "java" );
		parser.addVar( "require" );
		try {
			return parser.RequiredModuleSource();
		} catch(ParseException e) {
			throw new LuanException( e.getFancyMessage() );
		}
	}

	private LuanCompiler() {}  // never
}