/*
 *  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 cn.exlive.exbooter.configure;

import com.netflix.zuul.context.RequestContext;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.collections.keyvalue.DefaultKeyValue;
import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.netflix.zuul.filters.Route;
import org.springframework.cloud.netflix.zuul.filters.SimpleRouteLocator;
import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;

import java.net.URI;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Random;
import java.util.stream.Collectors;

/**
 * <pre>
 *
 * Created by zhenqin.
 * User: zhenqin
 * Date: 2022/4/25
 * Time: 下午7:12
 *
 * </pre>
 *
 * @author zhenqin
 */
@Slf4j
public class ApiRouteLocator extends SimpleRouteLocator {

    /**
     * zull 配置
     */
    final ZuulProperties properties;

    /**
     * 随机策略
     */
    final Random r = new Random();

    public ApiRouteLocator(String servletPath, ZuulProperties properties) {
        super(servletPath, properties);
        this.properties = properties;
    }

    @Override
    protected Route getRoute(ZuulProperties.ZuulRoute route, String path) {
        if (route == null) {
            return null;
        }
        RequestContext ctx = RequestContext.getCurrentContext();
        final String referer = ctx.getRequest().getHeader("Referer");
        final Map<String, List<String>> queryParams = Optional.ofNullable(ctx.getRequestQueryParams()).orElse(new HashMap<>());
        String clusterId = queryParams.get("clusterId") == null ? null : StringUtils.join(queryParams.get("clusterId"), ",");
        if (StringUtils.isBlank(clusterId) && StringUtils.isNotBlank(referer)) {
            // 如果 URL 中没有，从 Referer 中获取
            final String query = URI.create(referer).getQuery();
            final Map<String, String> kv = Arrays.stream(query.split("&")).filter(StringUtils::isNotBlank).map(it -> {
                final String[] split = it.split("=");
                return split.length > 1 ? new DefaultKeyValue(split[0], split[1]) : new DefaultKeyValue(split[0], "");
            }).collect(Collectors.toMap(e -> (String)e.getKey(), e -> (String)e.getValue()));
            clusterId = kv.get("clusterId");
        }
        log.info("clusterId: {} and referer: {}", clusterId, referer);
        String targetPath = path;
        String prefix = this.properties.getPrefix();
        if (prefix.endsWith("/")) {
            prefix = prefix.substring(0, prefix.length() - 1);
        }
        if (path.startsWith(prefix + "/") && this.properties.isStripPrefix()) {
            targetPath = path.substring(prefix.length());
        }
        if (route.isStripPrefix()) {
            int index = route.getPath().indexOf("*") - 1;
            if (index > 0) {
                String routePrefix = route.getPath().substring(0, index);
                targetPath = targetPath.replaceFirst(routePrefix, "");
                prefix = prefix + routePrefix;
            }
        }
        Boolean retryable = this.properties.getRetryable();
        if (route.getRetryable() != null) {
            retryable = route.getRetryable();
        }

        final HashMap<String, String> globalVariables = new HashMap<>();
        // cluster: 1 path: /damp/aaa/bbb match to: http://localhost:8083/damp
        log.info("cluster: {} path: {} match to: {}", clusterId, path, route.getLocation());
        // 如果包含逗号，说明有多个地址，需要负载均衡
        if (route.getLocation().contains(",")) {
            final String[] segs = route.getLocation().split(",");
            // 随机策略
            String loc = segs[r.nextInt(segs.length)];
            // 替换路由地址
            // loc = PlaceholderUtils.replacePlaceholders(loc, globalVariables, Constants.REGEX_VARIABLE);
            // log.info("loc->> " + loc);
            return new Route(route.getId(),
                    targetPath,
                    loc,
                    prefix,
                    retryable,
                    route.isCustomSensitiveHeaders() ? route.getSensitiveHeaders() : null,
                    route.isStripPrefix());
        }
        // 替换路由地址
        // String loc = PlaceholderUtils.replacePlaceholders(route.getLocation(), globalVariables, Constants.REGEX_VARIABLE);
        return new Route(route.getId(),
                targetPath,
                route.getLocation(),
                prefix,
                retryable,
                route.isCustomSensitiveHeaders() ? route.getSensitiveHeaders() : null,
                route.isStripPrefix());
    }

}