package org.simantics.scl.compiler.constants.generic;

import org.cojen.classfile.TypeDesc;
import org.objectweb.asm.Label;
import org.simantics.scl.compiler.internal.codegen.references.Val;
import org.simantics.scl.compiler.internal.codegen.utils.LocalVariable;
import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
import org.simantics.scl.compiler.internal.codegen.utils.PreparationStep;
import org.simantics.scl.compiler.internal.codegen.utils.SCLContextPreparationStep;
import org.simantics.scl.compiler.top.SCLCompilerConfiguration;

public class ThreadLocalStackItem implements StackItem, PreparationStep<LocalVariable> {
    
    private static final TypeDesc THREAD_LOCAL = 
            TypeDesc.forClass(ThreadLocal.class);
    
    String variableName;
    TypeDesc type;
    
    public ThreadLocalStackItem(String variableName, TypeDesc type) {
        this.variableName = variableName;
        this.type = type;
    }

    @Override
    public void push(MethodBuilder mb, Val[] parameters) {
        mb.loadLocal(mb.getPreparation(this));
    }

    @Override
    public void prepare(MethodBuilder mb) {
        LocalVariable var = mb.getPreparation(this);
        if(var == null) {
            var = mb.createLocalVariable("context", type);
            LocalVariable sclContext = SCLContextPreparationStep.getCurrent(mb);
            mb.loadLocal(sclContext);
            mb.loadConstant(variableName);
            mb.invokeVirtual("gnu/trove/map/hash/THashMap", "get", 
                    TypeDesc.OBJECT, new TypeDesc[] {TypeDesc.OBJECT});
            mb.checkCast(type);
            mb.storeLocal(var);
            
            if(SCLCompilerConfiguration.NULL_CHECK_THREAD_LOCAL_VARIABLES) {
                Label exit = mb.createLabel();
                mb.loadLocal(var);
                mb.ifNullBranch(exit, false);

                // This code should me redundant because of static type caughts the problem
                mb.newObject(TypeDesc.forClass(IllegalStateException.class));
                mb.dup();
                mb.loadConstant("Thread local variable missing");
                mb.invokeConstructor(TypeDesc.forClass(IllegalStateException.class), 
                        new TypeDesc[] {TypeDesc.STRING});
                mb.throwObject();

                mb.setLocation(exit);
            }
            
            mb.addPreparation(this, var);
        }
    }

    @Override
    public int hashCode() {
        return 234234 + type.hashCode() + 31*variableName.hashCode();
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        ThreadLocalStackItem other = (ThreadLocalStackItem) obj;
        return variableName.equals(other.variableName)
                && type.equals(other.type); 
    }    
    
}