package org.nutz.mvc.view;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.nutz.lang.Lang;
import org.nutz.mvc.View;

/**
 * 返回特定的响应码
 * <p/>
 * <b>注意,400或以上,会调用resp.sendError,而非resp.setStatus.这样做的原因是
 * errorPage的配置,只有resp.sendError会触发,且绝大多数情况下,只会配置400或以上</b>
 * 
 * @author MingMing
 * 
 */
public class HttpStatusView implements View {

    public static final View HTTP_404 = new HttpStatusView(404);
    // public static final View HTTP_400 = new HttpStatusView(400);
    public static final View HTTP_500 = new HttpStatusView(500);
    public static final View HTTP_502 = new HttpStatusView(502);

    /**
     * 这个异常用于，在某个入口函数,如果你声明了 `@Fail("http:500")` 但是你真正的返回值想根据运行时决定。 <br>
     * 那么，你就直接抛这个异常好了
     * 
     * @author zozoh(zozohtnt@gmail.com)
     */
    public static class HttpStatusException extends RuntimeException {

        private static final long serialVersionUID = 4035188583429445028L;

        private int status;

        public int getStatus() {
            return status;
        }

        public void setStatus(int status) {
            this.status = status;
        }

        public HttpStatusException(int status) {
            this.status = status;
        }

        public HttpStatusException(int status, String fmt, Object... args) {
            super(String.format(fmt, args));
            this.status = status;
        }

    }

    private int statusCode;

    public HttpStatusView(int statusCode) {
        this.statusCode = statusCode;
    }

    public void render(HttpServletRequest req,
                       HttpServletResponse resp,
                       Object obj) {
        int code = this.statusCode;
        if (obj != null && obj instanceof HttpStatusException) {
            code = ((HttpStatusException) obj).getStatus();
        }

        if (code >= 400)
            try {
                resp.sendError(code);
            }
            catch (IOException e) {
                throw Lang.wrapThrow(e);
            }
        else
            resp.setStatus(code);
    }

}