package com.moon.server.helper;

import com.moon.server.entity.all.StaticData;
import com.moon.server.entity.sys.ResEntity;
import org.apache.http.*;
import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.entity.InputStreamEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicHeader;
import org.apache.http.message.BasicHttpEntityEnclosingRequest;
import org.apache.http.message.BasicHttpRequest;
import org.apache.http.message.HeaderGroup;
import org.apache.http.util.EntityUtils;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.HttpCookie;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import java.util.Enumeration;

/**
 * Http帮助类
 * @author WWW
 */
public class HttpHelper {
    private final static String HTTP_SLASH2 = "://";

    private final static String HTTP_SLASH = "/";

    private final static Integer THREE = 3;

    protected static final HeaderGroup HOP_HEADERS;

    static {
        HOP_HEADERS = new HeaderGroup();

        String[] headers = new String[]{
                "Connection", "Keep-Alive", "Proxy-Authenticate", "Proxy-Authorization",
                "TE", "Trailers", "Transfer-Encoding", "Upgrade",
                //"X-RateLimit-Burst-Capacity", "X-RateLimit-Remaining", "X-RateLimit-Replenish-Rate",
                "Access-Control-Allow-Origin", "Access-Control-Allow-Credentials", "Access-Control-Allow-Headers"};

        for (String header : headers) {
            HOP_HEADERS.addHeader(new BasicHeader(header, null));
        }
    }

    public void service(HttpServletRequest request, HttpServletResponse response, ResEntity entity, String url) throws ServletException, IOException {
        HttpRequest proxyRequest;
        if (request.getHeader(HttpHeaders.CONTENT_LENGTH) != null || request.getHeader(HttpHeaders.TRANSFER_ENCODING) != null) {
            proxyRequest = newProxyRequestWithEntity(request, url);
        } else {
            proxyRequest = new BasicHttpRequest(request.getMethod(), url);
        }

        HttpHost host = this.getTargetHost(url);
        // copyRequestHeaders(request, proxyRequest, host);
        //setXrForwardedForHeader(request, proxyRequest);

        // if (!StringHelper.isEmpty(cookie)) proxyRequest.addHeader("Cookie", cookie + "; ")

        CloseableHttpClient client = null;
        HttpResponse proxyResponse = null;
        try {
            client = this.createHttpClient();
            proxyResponse = client.execute(host, proxyRequest);

            int statusCode = proxyResponse.getStatusLine().getStatusCode();
            // response.setStatus(statusCode, proxyResponse.getStatusLine().getReasonPhrase())
            response.setStatus(statusCode);

            copyResponseHeaders(proxyResponse, request, response, url);

            if (statusCode == HttpServletResponse.SC_NOT_MODIFIED) {
                response.setIntHeader(HttpHeaders.CONTENT_LENGTH, 0);
            } else {
                copyResponseEntity(proxyResponse, request, response, entity);
            }
        } catch (Exception ex) {
            throw new ServletException(ex.getMessage());
        } finally {
            if (proxyResponse != null) {
                EntityUtils.consumeQuietly(proxyResponse.getEntity());
            }
            if (client != null) {
                client.close();
            }
        }
    }

    protected HttpRequest newProxyRequestWithEntity(HttpServletRequest request, String url) throws IOException {
        String method = request.getMethod();
        HttpEntityEnclosingRequest proxyRequest = new BasicHttpEntityEnclosingRequest(method, url);
        proxyRequest.setEntity(new InputStreamEntity(request.getInputStream(), getContentLength(request)));
        //String str = EntityUtils.toString(proxyRequest.getEntity(), "UTF-8")

        return proxyRequest;
    }

    private long getContentLength(HttpServletRequest request) {
        String contentLengthHeader = request.getHeader("Content-Length");
        if (contentLengthHeader != null) {
            return Long.parseLong(contentLengthHeader);
        }

        return -1L;
    }

    protected void copyRequestHeaders(HttpServletRequest request, HttpRequest proxyRequest, HttpHost host) {
        @SuppressWarnings("unchecked")
        Enumeration<String> enumerationOfHeaderNames = request.getHeaderNames();

        while (enumerationOfHeaderNames.hasMoreElements()) {
            String headerName = enumerationOfHeaderNames.nextElement();
            copyRequestHeader(request, proxyRequest, host, headerName);
        }
    }

    protected void copyRequestHeader(HttpServletRequest request, HttpRequest proxyRequest, HttpHost host, String headerName) {
        if (headerName.equalsIgnoreCase(HttpHeaders.CONTENT_LENGTH) || HOP_HEADERS.containsHeader(headerName)) {
            return;
        }

        @SuppressWarnings("unchecked")
        Enumeration<String> headers = request.getHeaders(headerName);
        while (headers.hasMoreElements()) {
            String headerValue = headers.nextElement();
            if (headerName.equalsIgnoreCase(HttpHeaders.HOST)) {
                headerValue = host.getHostName();
                if (host.getPort() != -1) {
                    headerValue += ":" + host.getPort();
                }
            } else if (headerName.equalsIgnoreCase(org.apache.http.cookie.SM.COOKIE)) {
                headerValue = getRealCookie(headerValue);
            }

            proxyRequest.addHeader(headerName, headerValue);
        }
    }

    protected HttpHost getTargetHost(String url) throws ServletException {
        try {
            URI uri = new URI(url);

            return URIUtils.extractHost(uri);
        } catch (URISyntaxException ex) {
            throw new ServletException(ex.getMessage());
        }
    }

    protected String getRealCookie(String cookieValue) {
        StringBuilder escapedCookie = new StringBuilder();

        String[] cookies = cookieValue.split("[;,]");
        for (String cookie : cookies) {
            String[] cookieSplit = cookie.split("=");
            if (cookieSplit.length == 2) {
                String cookieName = cookieSplit[0].trim();
                if (cookieName.startsWith(cookieName)) {
                    cookieName = cookieName.substring(cookieName.length());
                    if (escapedCookie.length() > 0) {
                        escapedCookie.append("; ");
                    }
                    escapedCookie.append(cookieName).append("=").append(cookieSplit[1].trim());
                }
            }
        }

        return escapedCookie.toString();
    }

    private void setXrForwardedForHeader(HttpServletRequest request, HttpRequest proxyRequest) {
        String forHeaderName = "X-Forwarded-For";
        String forHeader = request.getRemoteAddr();
        String existingForHeader = request.getHeader(forHeaderName);
        if (existingForHeader != null) {
            forHeader = existingForHeader + ", " + forHeader;
        }
        proxyRequest.setHeader(forHeaderName, forHeader);

        String protoHeaderName = "X-Forwarded-Proto";
        String protoHeader = request.getScheme();
        proxyRequest.setHeader(protoHeaderName, protoHeader);
    }

    protected CloseableHttpClient createHttpClient() {
        RequestConfig requestConfig = RequestConfig.custom()
                .setRedirectsEnabled(false)
                .setCookieSpec(CookieSpecs.IGNORE_COOKIES)
                .setConnectTimeout(-1)
                .setSocketTimeout(-1)
                .build();

        // return HttpClientBuilder.create().setDefaultRequestConfig(requestConfig).build()
        return HttpClients.custom()
                .setDefaultRequestConfig(requestConfig)
                .build();
    }

    protected void copyResponseHeaders(HttpResponse proxyResponse, HttpServletRequest request, HttpServletResponse response, String url) {
        for (Header header : proxyResponse.getAllHeaders()) {
            copyResponseHeader(request, response, header, url);
        }
    }

    protected void copyResponseHeader(HttpServletRequest request, HttpServletResponse response, Header header, String url) {
        String headerName = header.getName();
        if (HOP_HEADERS.containsHeader(headerName)) {
            return;
        }

        String headerValue = header.getValue();
        if (headerName.equalsIgnoreCase(org.apache.http.cookie.SM.SET_COOKIE) || headerName.equalsIgnoreCase(org.apache.http.cookie.SM.SET_COOKIE2)) {
            copyProxyCookie(request, response, headerValue);
        } else if (headerName.equalsIgnoreCase(HttpHeaders.LOCATION)) {
            response.addHeader(headerName, rewriteUrlFromResponse(request, url, headerValue));
        } else {
            response.addHeader(headerName, headerValue);
        }
    }

    protected void copyProxyCookie(HttpServletRequest request, HttpServletResponse response, String headerValue) {
        String path = request.getContextPath() + request.getServletPath();
        if (path.isEmpty()) {
            path = "/";
        }

        for (HttpCookie cookie : HttpCookie.parse(headerValue)) {
            Cookie servletCookie = new Cookie(cookie.getName(), cookie.getValue());
            servletCookie.setComment(cookie.getComment());
            servletCookie.setMaxAge((int) cookie.getMaxAge());
            servletCookie.setPath(path);

            servletCookie.setSecure(cookie.getSecure());
            servletCookie.setVersion(cookie.getVersion());
            response.addCookie(servletCookie);
        }
    }

    protected String rewriteUrlFromResponse(HttpServletRequest request, String targetUri, String theUrl) {
        if (theUrl.startsWith(targetUri)) {
            StringBuffer curUrl = request.getRequestURL();

            int pos;
            if ((pos = curUrl.indexOf(HTTP_SLASH2)) >= 0) {
                if ((pos = curUrl.indexOf(HTTP_SLASH, pos + THREE)) >= 0) {
                    curUrl.setLength(pos);
                }
            }

            curUrl.append(request.getContextPath());
            curUrl.append(request.getServletPath());
            curUrl.append(theUrl, targetUri.length(), theUrl.length());

            return curUrl.toString();
        }

        return theUrl;
    }

    protected void copyResponseEntity(HttpResponse proxyResponse, HttpServletRequest request, HttpServletResponse response, ResEntity res) throws IOException {
        HttpEntity entity = proxyResponse.getEntity();
        if (null == entity) {
            return;
        }

        switch (res.getCategory()) {
            case 2:
                copeGeoService(proxyResponse, request, response, res);
                break;
            case 3:
                copeSjService(proxyResponse, request, response, res);
                break;
            default:
                entity.writeTo(response.getOutputStream());
                break;
        }
    }

    private void copeGeoService(HttpResponse proxyResponse, HttpServletRequest request, HttpServletResponse response, ResEntity res) throws IOException {
        if (!StaticData.GET_CAPABILITIES.equals(res.getBak())) {
            proxyResponse.getEntity().writeTo(response.getOutputStream());
            return;
        }

        String str = EntityUtils.toString(proxyResponse.getEntity(), "UTF-8");
        String proxyUrl = res.getProxy().replace("{token}", response.getHeader("token"));
        proxyUrl = request.getRequestURL().substring(0, request.getRequestURL().indexOf(proxyUrl) + proxyUrl.length());
        str = str.replace(res.getUrl(), proxyUrl);

        int index = str.indexOf(StaticData.QUERYABLE);
        while (index > -1) {
            int start = str.indexOf("<Name>", index) + StaticData.I6;
            int end = str.indexOf("</Layer>", index) + StaticData.I8;

            String name = ":" + str.substring(start, str.indexOf("</Name>", start));
            if (!res.getTab().contains(name)) {
                // index = str.lastIndexOf(">", index)
                end = str.indexOf("<", end);
                str = str.substring(0, index) + str.substring(end);
                index = str.indexOf(StaticData.QUERYABLE, index);
            } else {
                index = str.indexOf(StaticData.QUERYABLE, end);
            }
        }

        byte[] bytes = str.getBytes(StandardCharsets.UTF_8);
        response.setContentLength(bytes.length);
        response.getOutputStream().write(bytes);
    }

    private void copeSjService(HttpResponse proxyResponse, HttpServletRequest request, HttpServletResponse response, ResEntity res) throws IOException {
        Header[] headers = proxyResponse.getHeaders("content-type");
        if (null != headers && headers.length > 0 && headers[0].getValue().contains(StaticData.TEXT_XML)) {
            String str = filterStr(request, response, res, EntityUtils.toString(proxyResponse.getEntity(), "UTF-8"));
            byte[] bytes = str.getBytes(StandardCharsets.UTF_8);
            response.setContentLength(bytes.length);
            response.getOutputStream().write(bytes);
        } else {
            proxyResponse.getEntity().writeTo(response.getOutputStream());
        }
    }

    private String filterStr(HttpServletRequest request, HttpServletResponse response, ResEntity res, String str) {
        if (str.contains(res.getUrl())) {
            String proxyUrl = res.getProxy().replace("{token}", response.getHeader("token"));
            proxyUrl = request.getRequestURL().substring(0, request.getRequestURL().indexOf(proxyUrl) + proxyUrl.length());
            str = str.replace(res.getUrl(), proxyUrl);

            if (!StringHelper.isEmpty(res.getArgs())) {
                // str = str.replace("?" + res.getArgs(), "").replace("&amp;" + res.getArgs(), "")
                str = str.replace("?" + res.getArgs() + "\"", "\"").replace("&amp;" + res.getArgs() + "\"", "\"")
                        .replace("?" + res.getArgs() + "&amp;", "?").replace("&amp;" + res.getArgs() + "&amp;", "&amp;");
            }

            if (StaticData.I3 == res.getCategory() && str.contains(StaticData.REST_LAYER)) {
                str = str.replace(res.getUrl().replace("/v6/wmts/", StaticData.REST_LAYER), proxyUrl.replace("/proxy/", "/proxy/rest/"));
            }
        }

        return str;
    }
}