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/*
 * Copyright (c) 2020 Richard Hauswald - https://quantummaid.de/.
 *
 * 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 de.quantummaid.httpmaid.servlet;

import de.quantummaid.httpmaid.HttpMaid;
import de.quantummaid.httpmaid.endpoint.RawHttpRequest;
import de.quantummaid.httpmaid.endpoint.RawHttpRequestBuilder;
import de.quantummaid.httpmaid.http.Headers;
import de.quantummaid.httpmaid.http.HeadersBuilder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;

import static java.util.Optional.ofNullable;

public final class ServletHandling {

    private ServletHandling() {
    }

    public static void handle(final HttpMaid httpMaid,
                              final HttpServletRequest request,
                              final HttpServletResponse response) {
        httpMaid.handleRequest(() -> {
            final RawHttpRequestBuilder builder = extractMetaDataFromHttpServletRequest(request);
            final InputStream body = request.getInputStream();
            builder.withBody(body);
            return builder.build();
        }, rawResponse -> {
            rawResponse.setHeaders(response::addHeader);
            final int responseStatus = rawResponse.status();
            response.setStatus(responseStatus);
            final OutputStream outputStream = response.getOutputStream();
            rawResponse.streamBodyToOutputStream(outputStream);
        });
    }

    public static RawHttpRequestBuilder extractMetaDataFromHttpServletRequest(final HttpServletRequest request) {
        final RawHttpRequestBuilder builder = RawHttpRequest.rawHttpRequestBuilder();
        final String path = request.getPathInfo();
        builder.withPath(path);
        final String method = request.getMethod();
        builder.withMethod(method);
        final Headers headers = extractHeaders(request);
        builder.withHeaders(headers);
        final String queryString = ofNullable(request.getQueryString()).orElse("");
        builder.withQueryString(queryString);
        return builder;
    }

    private static Headers extractHeaders(final HttpServletRequest request) {
        final HeadersBuilder headersBuilder = HeadersBuilder.headersBuilder();
        final Enumeration headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            final String headerName = headerNames.nextElement();
            final Enumeration values = request.getHeaders(headerName);
            while (values.hasMoreElements()) {
                final String value = values.nextElement();
                headersBuilder.withAdditionalHeader(headerName, value);
            }
        }
        return headersBuilder.build();
    }
}