/**
 * Copyright 2013-2014 Guoqiang Chen, Shanghai, China. All rights reserved.
 *
 * Email: subchen@gmail.com
 * URL: http://subchen.github.io/
 *
 * 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 jetbrick.web.mvc.interceptor;

import java.util.List;
import jetbrick.web.mvc.*;
import jetbrick.web.mvc.action.ActionInfo;

/**
 * 依次执行所有的 Intercepter，完成后在执行 action
 */
public class InterceptorChainImpl implements InterceptorChain {
    private final List<Interceptor> interceptors;
    private final RequestContext ctx;
    private int currentIndex = 0;
    private ResultInfo result;

    public InterceptorChainImpl(List<Interceptor> interceptors, RequestContext ctx) {
        this.interceptors = interceptors;
        this.ctx = ctx;
    }

    @Override
    public void invoke() throws Exception {
        if (currentIndex < interceptors.size()) {
            Interceptor interceptor = interceptors.get(currentIndex++);
            interceptor.intercept(ctx, this);
        } else {
            executeAction(ctx);
        }
    }

    public ResultInfo getResult() {
        return result;
    }

    private void executeAction(RequestContext ctx) throws Exception {
        RouteInfo route = ctx.getRouteInfo();
        if (route == null || route == RouteInfo.NOT_FOUND) {
            throw new WebException("Action not found for URL: " + ctx.getPathInfo());
        }

        ActionInfo action = route.getAction();
        result = action.execute(ctx);
    }
}