package shadersmodcore.transform;

import java.util.Iterator;

import org.lwjgl.opengl.GL11;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import static org.objectweb.asm.Opcodes.*;
import org.objectweb.asm.commons.Remapper;
import org.objectweb.asm.tree.MethodNode;


import net.minecraft.launchwrapper.IClassTransformer;

public class SMCCTItemRenderer implements IClassTransformer {

	@Override
	public byte[] transform(String par1, String par2, byte[] par3) {
		SMCLog.fine("transforming %s %s",par1,par2);
		ClassReader cr = new ClassReader(par3);
		ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS);
		CVTransform cv = new CVTransform(cw);
		cr.accept(cv,0);
		return cw.toByteArray();
	}

	private static class CVTransform extends ClassVisitor
	{
		String classname;
		public CVTransform(ClassVisitor cv)
		{
			super(Opcodes.ASM4, cv);		
		}

		Names.Meth renderItemIrt = new Names.Meth(Names.itemRenderer_,"renderItem","("+Names.entityLivingBase_.desc+Names.itemStack_.desc+"ILnet/minecraftforge/client/IItemRenderer$ItemRenderType;)V");
		
		@Override
		public void visit(int version, int access, String name,
				String signature, String superName, String[] interfaces) {
			classname = name;
			//SMCLog.info(" class %s",name);
			cv.visit(version, access, name, signature, superName, interfaces);
		}

		@Override
		public MethodVisitor visitMethod(int access, String name, String desc,
				String signature, String[] exceptions) 
		{
			//SMCLog.info("  method %s.%s%s",classname,name,desc);
			if (Names.itemRenderer_updateEquipped.equalsNameDesc(name, desc))
			{
				SMCLog.finer("  patch method %s.%s%s",classname,name,desc);
				return new MVupdate(cv.visitMethod(access, name, desc, signature, exceptions));
			} else if (Names.itemRenderer_renderItem.equalsNameDesc(name, desc))
			{
				SMCLog.finer("  patch method %s.%s%s",classname,name,desc);
				return new MVrenderItem(cv.visitMethod(access, name, desc, signature, exceptions));
			} else if (renderItemIrt.equalsNameDesc(name, desc))
			{
				SMCLog.finer("  patch method %s.%s%s",classname,name,desc);
				return new MVrenderItem(cv.visitMethod(access, name, desc, signature, exceptions));
			}
			return cv.visitMethod(access, name, desc, signature, exceptions);
		}
		
	}

	private static class MVupdate extends MethodVisitor
	{
		public MVupdate(MethodVisitor mv) {
			super(Opcodes.ASM4, mv);
		}

		@Override
		public void visitFieldInsn(int opcode, String owner, String name, String desc) {
			if (opcode==PUTFIELD && Names.itemRenderer_itemToRender.equals(owner, name, desc)) {
				mv.visitInsn(DUP);
				mv.visitFieldInsn(PUTSTATIC, "shadersmodcore/client/Shaders", "itemToRender", Names.itemStack_.desc);
			}
			mv.visitFieldInsn(opcode, owner, name, desc);
		}
		
	}

	private static class MVrenderItem extends MethodVisitor
	{
		public MVrenderItem(MethodVisitor mv) {
			super(Opcodes.ASM4, mv);
		}
		
		int state = 0;

		@Override
		public void visitInsn(int opcode) {
			if (state==1) {
				if (opcode==ICONST_0) {
					++state;
					opcode = ICONST_1;
				}
			}
			mv.visitInsn(opcode);
		}
		
		@Override
		public void visitIntInsn(int opcode, int operand) {
			if (state==0) {
				if (opcode==SIPUSH && operand==GL11.GL_BLEND) {
					++state;
				}
			}
			mv.visitIntInsn(opcode, operand);
		}
	}
}