// Copyright (c) Corporation for National Research Initiatives
package org.python.core;

import java.util.List;

import org.python.util.Generic;

public class PyCompoundCallable extends PyObject implements Traverseproc {

    private List<PyObject> callables = Generic.list();

    private PySystemState systemState = Py.getSystemState();

    public void append(PyObject callable) {
        callables.add(callable);
    }

    public void clear() {
        callables.clear();
    }

    public PyObject __call__(PyObject[] args, String[] keywords) {
        // Set the system state to handle callbacks from java threads
        Py.setSystemState(systemState);
        for (PyObject callable : callables) {
            callable.__call__(args, keywords);
        }
        return Py.None;
    }

    public String toString() {
        return "<CompoundCallable with " + callables.size() + " callables>";
    }


    /* Traverseproc implementation */
    @Override
    public int traverse(Visitproc visit, Object arg) {
        int retValue;
        if (systemState != null) {
        	retValue = visit.visit(systemState, arg);
	        if (retValue != 0) {
	            return retValue;
	        }
        }
        if (callables != null) {
	        for (PyObject ob: callables) {
	            retValue = visit.visit(ob, arg);
	            if (retValue != 0) {
	                return retValue;
	            }
	        }
        }
        return 0;
    }

    @Override
    public boolean refersDirectlyTo(PyObject ob) {
        return ob != null && (ob == systemState || callables.contains(ob));
    }
}