package luan;

import java.util.List;
import luan.modules.BasicLuan;
import luan.impl.LuanCompiler;


public final class Luan {

	public static void main(String[] args) throws LuanException {
		LuanState luan = new LuanState();
		LuanFunction standalone = (LuanFunction)BasicLuan.load_file(luan,"classpath:luan/cmd_line.luan");
		standalone.call(luan,args);
	}

	public static Object first(Object obj) {
		if( !(obj instanceof Object[]) )
			return obj;
		Object[] a = (Object[])obj;
		return a.length==0 ? null : a[0];
	}

	public static Object[] array(Object obj) {
		return obj instanceof Object[] ? (Object[])obj : new Object[]{obj};
	}

	public static String type(Object obj) {
		if( obj == null )
			return "nil";
		if( obj instanceof String )
			return "string";
		if( obj instanceof Boolean )
			return "boolean";
		if( obj instanceof Number )
			return "number";
		if( obj instanceof LuanTable )
			return "table";
		if( obj instanceof LuanFunction )
			return "function";
		if( obj instanceof byte[] )
			return "binary";
		return "java";
	}

	public static String toString(Number n) {
		if( n instanceof Integer )
			return n.toString();
		int i = n.intValue();
		if( i == n.doubleValue() )
			return Integer.toString(i);
		String s = n.toString();
		int iE = s.indexOf('E');
		String ending  = null;
		if( iE != -1 ) {
			ending = s.substring(iE);
			s = s.substring(0,iE);
		}
		if( s.endsWith(".0") )
			s = s.substring(0,s.length()-2);
		if( ending != null )
			s += ending;
		return s;
	}

	public static Integer asInteger(Object obj) {
		if( obj instanceof Integer )
			return (Integer)obj;
		if( !(obj instanceof Number) )
			return null;
		Number n = (Number)obj;
		int i = n.intValue();
		return i==n.doubleValue() ? Integer.valueOf(i) : null;
	}

	public static String stringEncode(String s) {
		s = s.replace("\\","\\\\");
		s = s.replace("\u0007","\\a");
		s = s.replace("\b","\\b");
		s = s.replace("\f","\\f");
		s = s.replace("\n","\\n");
		s = s.replace("\r","\\r");
		s = s.replace("\t","\\t");
		s = s.replace("\u000b","\\v");
		s = s.replace("\"","\\\"");
		s = s.replace("\'","\\'");
		return s;
	}


	// from LuanState

	public static Boolean checkBoolean(Object obj) throws LuanException {
		if( obj instanceof Boolean )
			return (Boolean)obj;
		throw new LuanException("attempt to use a " + Luan.type(obj) + " value as a boolean" );
	}

	public static String checkString(Object obj) throws LuanException {
		if( obj instanceof String )
			return (String)obj;
		throw new LuanException("attempt to use a " + Luan.type(obj) + " value as a string" );
	}

	public static LuanFunction checkFunction(Object obj) throws LuanException {
		if( obj instanceof LuanFunction )
			return (LuanFunction)obj;
		throw new LuanException("attempt to call a " + Luan.type(obj) + " value" );
	}

	public static boolean isLessThan(LuanState luan,Object o1,Object o2) throws LuanException {
		if( o1 instanceof Number && o2 instanceof Number ) {
			Number n1 = (Number)o1;
			Number n2 = (Number)o2;
			return n1.doubleValue() < n2.doubleValue();
		}
		if( o1 instanceof String && o2 instanceof String ) {
			String s1 = (String)o1;
			String s2 = (String)o2;
			return s1.compareTo(s2) < 0;
		}
		LuanFunction fn = getBinHandler("__lt",o1,o2);
		if( fn != null )
			return checkBoolean( Luan.first(fn.call(luan,new Object[]{o1,o2})) );
		throw new LuanException( "attempt to compare " + Luan.type(o1) + " with " + Luan.type(o2) );
	}

	public static LuanFunction getBinHandler(String op,Object o1,Object o2) throws LuanException {
		if( o1 instanceof LuanTable ) {
			LuanFunction f1 = getHandlerFunction(op,(LuanTable)o1);
			if( f1 != null )
				return f1;
		}
		return o2 instanceof LuanTable ? getHandlerFunction(op,(LuanTable)o2) : null;
	}

	public static LuanFunction getHandlerFunction(String op,LuanTable t) throws LuanException {
		Object f = t.getHandler(op);
		if( f == null )
			return null;
		return checkFunction(f);
	}

	public static LuanFunction load(String text,String sourceName,LuanTable env)
		throws LuanException
	{
		return LuanCompiler.compile(text,sourceName,env);
	}

	public static LuanFunction load(String text,String sourceName)
		throws LuanException
	{
		return load(text,sourceName,null);
	}


	private Luan() {}  // never
}