/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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 org.apache.asyncweb.server.errorReporting;

import java.io.UnsupportedEncodingException;

import org.apache.mina.common.IoBuffer;
import org.apache.asyncweb.common.MutableHttpResponse;
import org.apache.asyncweb.common.HttpResponseStatus.Category;
import org.apache.asyncweb.common.HttpRequest;
import org.apache.asyncweb.common.HttpResponseStatus;
import org.apache.asyncweb.server.util.StringBundle;

public class StandardResponseFormatter implements ErrorResponseFormatter {

    private static final StringBundle bundle = StringBundle
            .getBundle(StandardResponseFormatter.class.getPackage().getName());

    public void formatResponse(HttpRequest request, MutableHttpResponse response) {
        if (shouldFormat(response)) {
            doFormat(request, response);
            response.addHeader("content-type", "text/html");
        }
    }

    private boolean shouldFormat(MutableHttpResponse response) {
        boolean shouldFormat = false;
        if (!response.getContent().hasRemaining()) {
            HttpResponseStatus status = response.getStatus();
            HttpResponseStatus.Category category = response.getStatus()
                    .getCategory();
            shouldFormat = status.allowsMessageBody()
                    && (category == Category.CLIENT_ERROR || category == Category.SERVER_ERROR);
        }
        return shouldFormat;
    }

    private void doFormat( HttpRequest request, MutableHttpResponse response) {
        StringBuilder html = new StringBuilder(1024);
        html.append("<html><head><title>");
        html.append("AsyncWeb Server - ");
        html.append(bundle.getString("errorMessage"));
        html.append("</title><style><!--");
        CSS.appendTo(html).append("--></style>");
        html.append("</head>");
        html.append("<h1>");
        html.append(bundle.getString("errorTitle"));
        html.append("</h1>");
        response.getStatusReasonPhrase();
        String code = String.valueOf(response.getStatus().getCode());
        html.append("<h1>");
        html.append(bundle.getString("statusInfo", code));
        html.append("</h1>");
        html.append("<HR size=\"1\" noshade=\"noshade\">");

        html.append("<p><table cellpadding=\"5\">");
        appendInfo("statusCode",
                String.valueOf(response.getStatus().getCode()), html);
        appendInfo("description", getErrorMessage(response), html);
        appendInfo("requestMethod", request.getMethod().toString(), html);
        html.append("</table></p>");

        html.append("<HR size=\"1\" noshade=\"noshade\">");
        html.append("<H2>AsyncWeb Server</H2></body></html>");

        IoBuffer out = IoBuffer.allocate(html.length());

        // TODO: Need to sort this out when we start dealing with character encodings
        try {
            byte[] bytes = html.toString().getBytes("US-ASCII");
            out.put(bytes);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }

        out.flip();
        response.setContent(out);
    }

    private void appendInfo(String title, String info, StringBuilder html) {
        html.append("<tr><th>").append(bundle.getString(title)).append("</th>");
        html.append("<td>").append(info).append("</td>");
    }

    private String getErrorMessage( MutableHttpResponse response) {
        int responseCode = response.getStatus().getCode();
        String errorMessage = response.getStatusReasonPhrase();
        if (errorMessage == null) {
            errorMessage = "";
        }
        return bundle.getString("http." + responseCode, errorMessage);
    }

}