/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.ide.eclipse.gltrace.state.transforms;

import com.android.ide.eclipse.gltrace.GLEnum;
import com.android.ide.eclipse.gltrace.state.GLIntegerProperty;
import com.android.ide.eclipse.gltrace.state.GLStateType;
import com.android.ide.eclipse.gltrace.state.IGLProperty;

/**
 * An {@link IGLPropertyAccessor} that retrieves the requested property in the
 * currently bound {@link GLEnum#GL_ARRAY_BUFFER} or {@link GLEnum#GL_ELEMENT_ARRAY_BUFFER}.
 */
public class CurrentVboPropertyAccessor implements IGLPropertyAccessor {
    private final int mContextId;
    private final IGLPropertyAccessor mVboBindingAccessor;
    private final GLStateType mVboProperty;

    public CurrentVboPropertyAccessor(int contextId, GLEnum target, GLStateType vboProperty) {
        mContextId = contextId;
        mVboProperty = vboProperty;

        GLStateType vboType;
        if (target == GLEnum.GL_ARRAY_BUFFER) {
            vboType = GLStateType.ARRAY_BUFFER_BINDING;
        } else {
            vboType = GLStateType.ELEMENT_ARRAY_BUFFER_BINDING;
        }

        mVboBindingAccessor = GLPropertyAccessor.makeAccessor(contextId,
                GLStateType.VERTEX_ARRAY_DATA,
                GLStateType.BUFFER_BINDINGS,
                vboType);
    }

    @Override
    public IGLProperty getProperty(IGLProperty state) {
        // obtain the current bound buffer
        IGLProperty currentBinding = mVboBindingAccessor.getProperty(state);
        if (!(currentBinding instanceof GLIntegerProperty)) {
            return null;
        }

        Integer buffer = (Integer) currentBinding.getValue();

        return GLPropertyAccessor.makeAccessor(mContextId,
                                               GLStateType.VERTEX_ARRAY_DATA,
                                               GLStateType.VBO,
                                               buffer,
                                               mVboProperty).getProperty(state);
    }

    @Override
    public String getPath() {
        return String.format("VERTEX_ARRAY_DATA/VBO/${currentBuffer}/%s", mVboProperty);
    }
}