/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed 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 com.alibaba.csp.sentinel.dashboard.controller.gateway;

import com.alibaba.csp.sentinel.dashboard.auth.AuthAction;
import com.alibaba.csp.sentinel.dashboard.auth.AuthService;
import com.alibaba.csp.sentinel.dashboard.client.SentinelApiClient;
import com.alibaba.csp.sentinel.dashboard.datasource.entity.gateway.GatewayFlowRuleEntity;
import com.alibaba.csp.sentinel.dashboard.datasource.entity.gateway.GatewayParamFlowItemEntity;
import com.alibaba.csp.sentinel.dashboard.discovery.MachineInfo;
import com.alibaba.csp.sentinel.dashboard.domain.Result;
import com.alibaba.csp.sentinel.dashboard.domain.vo.gateway.rule.AddFlowRuleReqVo;
import com.alibaba.csp.sentinel.dashboard.domain.vo.gateway.rule.GatewayParamFlowItemVo;
import com.alibaba.csp.sentinel.dashboard.domain.vo.gateway.rule.UpdateFlowRuleReqVo;
import com.alibaba.csp.sentinel.dashboard.repository.gateway.InMemGatewayFlowRuleStore;
import com.alibaba.csp.sentinel.util.StringUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Arrays;
import java.util.Date;
import java.util.List;

import static com.alibaba.csp.sentinel.adapter.gateway.common.SentinelGatewayConstants.*;
import static com.alibaba.csp.sentinel.dashboard.datasource.entity.gateway.GatewayFlowRuleEntity.*;
import static com.alibaba.csp.sentinel.slots.block.RuleConstant.*;

/**
 * Gateway flow rule Controller for manage gateway flow rules.
 *
 * @author cdfive
 * @since 1.7.0
 */
@RestController
@RequestMapping(value = "/gateway/flow")
public class GatewayFlowRuleController {

	private final Logger logger = LoggerFactory.getLogger(GatewayFlowRuleController.class);

	@Autowired
	private InMemGatewayFlowRuleStore repository;

	@Autowired
	private SentinelApiClient sentinelApiClient;

	@GetMapping("/list.json")
	@AuthAction(AuthService.PrivilegeType.READ_RULE)
	public Result<List<GatewayFlowRuleEntity>> queryFlowRules(String app, String ip, Integer port) {

		if (StringUtil.isEmpty(app)) {
			return Result.ofFail(-1, "app can't be null or empty");
		}
		if (StringUtil.isEmpty(ip)) {
			return Result.ofFail(-1, "ip can't be null or empty");
		}
		if (port == null) {
			return Result.ofFail(-1, "port can't be null");
		}

		try {
			List<GatewayFlowRuleEntity> rules = sentinelApiClient.fetchGatewayFlowRules(app, ip, port).get();
			repository.saveAll(rules);
			return Result.ofSuccess(rules);
		}
		catch (Throwable throwable) {
			logger.error("query gateway flow rules error:", throwable);
			return Result.ofThrowable(-1, throwable);
		}
	}

	@PostMapping("/new.json")
	@AuthAction(AuthService.PrivilegeType.WRITE_RULE)
	public Result<GatewayFlowRuleEntity> addFlowRule(@RequestBody AddFlowRuleReqVo reqVo) {

		String app = reqVo.getApp();
		if (StringUtil.isBlank(app)) {
			return Result.ofFail(-1, "app can't be null or empty");
		}

		GatewayFlowRuleEntity entity = new GatewayFlowRuleEntity();
		entity.setApp(app.trim());

		String ip = reqVo.getIp();
		if (StringUtil.isBlank(ip)) {
			return Result.ofFail(-1, "ip can't be null or empty");
		}
		entity.setIp(ip.trim());

		Integer port = reqVo.getPort();
		if (port == null) {
			return Result.ofFail(-1, "port can't be null");
		}
		entity.setPort(port);

		// API类型, Route ID或API分组
		Integer resourceMode = reqVo.getResourceMode();
		if (resourceMode == null) {
			return Result.ofFail(-1, "resourceMode can't be null");
		}
		if (!Arrays.asList(RESOURCE_MODE_ROUTE_ID, RESOURCE_MODE_CUSTOM_API_NAME).contains(resourceMode)) {
			return Result.ofFail(-1, "invalid resourceMode: " + resourceMode);
		}
		entity.setResourceMode(resourceMode);

		// API名称
		String resource = reqVo.getResource();
		if (StringUtil.isBlank(resource)) {
			return Result.ofFail(-1, "resource can't be null or empty");
		}
		entity.setResource(resource.trim());

		// 针对请求属性
		GatewayParamFlowItemVo paramItem = reqVo.getParamItem();
		if (paramItem != null) {
			GatewayParamFlowItemEntity itemEntity = new GatewayParamFlowItemEntity();
			entity.setParamItem(itemEntity);

			// 参数属性 0-ClientIP 1-Remote Host 2-Header 3-URL参数 4-Cookie
			Integer parseStrategy = paramItem.getParseStrategy();
			if (!Arrays.asList(PARAM_PARSE_STRATEGY_CLIENT_IP, PARAM_PARSE_STRATEGY_HOST, PARAM_PARSE_STRATEGY_HEADER,
					PARAM_PARSE_STRATEGY_URL_PARAM, PARAM_PARSE_STRATEGY_COOKIE).contains(parseStrategy)) {
				return Result.ofFail(-1, "invalid parseStrategy: " + parseStrategy);
			}
			itemEntity.setParseStrategy(paramItem.getParseStrategy());

			// 当参数属性为2-Header 3-URL参数 4-Cookie时，参数名称必填
			if (Arrays.asList(PARAM_PARSE_STRATEGY_HEADER, PARAM_PARSE_STRATEGY_URL_PARAM, PARAM_PARSE_STRATEGY_COOKIE)
					.contains(parseStrategy)) {
				// 参数名称
				String fieldName = paramItem.getFieldName();
				if (StringUtil.isBlank(fieldName)) {
					return Result.ofFail(-1, "fieldName can't be null or empty");
				}
				itemEntity.setFieldName(paramItem.getFieldName());
			}

			String pattern = paramItem.getPattern();
			// 如果匹配串不为空，验证匹配模式
			if (StringUtil.isNotEmpty(pattern)) {
				itemEntity.setPattern(pattern);
				Integer matchStrategy = paramItem.getMatchStrategy();
				if (!Arrays
						.asList(PARAM_MATCH_STRATEGY_EXACT, PARAM_MATCH_STRATEGY_CONTAINS, PARAM_MATCH_STRATEGY_REGEX)
						.contains(matchStrategy)) {
					return Result.ofFail(-1, "invalid matchStrategy: " + matchStrategy);
				}
				itemEntity.setMatchStrategy(matchStrategy);
			}
		}

		// 阈值类型 0-线程数 1-QPS
		Integer grade = reqVo.getGrade();
		if (grade == null) {
			return Result.ofFail(-1, "grade can't be null");
		}
		if (!Arrays.asList(FLOW_GRADE_THREAD, FLOW_GRADE_QPS).contains(grade)) {
			return Result.ofFail(-1, "invalid grade: " + grade);
		}
		entity.setGrade(grade);

		// QPS阈值
		Double count = reqVo.getCount();
		if (count == null) {
			return Result.ofFail(-1, "count can't be null");
		}
		if (count < 0) {
			return Result.ofFail(-1, "count should be at lease zero");
		}
		entity.setCount(count);

		// 间隔
		Long interval = reqVo.getInterval();
		if (interval == null) {
			return Result.ofFail(-1, "interval can't be null");
		}
		if (interval <= 0) {
			return Result.ofFail(-1, "interval should be greater than zero");
		}
		entity.setInterval(interval);

		// 间隔单位
		Integer intervalUnit = reqVo.getIntervalUnit();
		if (intervalUnit == null) {
			return Result.ofFail(-1, "intervalUnit can't be null");
		}
		if (!Arrays.asList(INTERVAL_UNIT_SECOND, INTERVAL_UNIT_MINUTE, INTERVAL_UNIT_HOUR, INTERVAL_UNIT_DAY)
				.contains(intervalUnit)) {
			return Result.ofFail(-1, "Invalid intervalUnit: " + intervalUnit);
		}
		entity.setIntervalUnit(intervalUnit);

		// 流控方式 0-快速失败 2-匀速排队
		Integer controlBehavior = reqVo.getControlBehavior();
		if (controlBehavior == null) {
			return Result.ofFail(-1, "controlBehavior can't be null");
		}
		if (!Arrays.asList(CONTROL_BEHAVIOR_DEFAULT, CONTROL_BEHAVIOR_RATE_LIMITER).contains(controlBehavior)) {
			return Result.ofFail(-1, "invalid controlBehavior: " + controlBehavior);
		}
		entity.setControlBehavior(controlBehavior);

		if (CONTROL_BEHAVIOR_DEFAULT == controlBehavior) {
			// 0-快速失败, 则Burst size必填
			Integer burst = reqVo.getBurst();
			if (burst == null) {
				return Result.ofFail(-1, "burst can't be null");
			}
			if (burst < 0) {
				return Result.ofFail(-1, "invalid burst: " + burst);
			}
			entity.setBurst(burst);
		}
		else if (CONTROL_BEHAVIOR_RATE_LIMITER == controlBehavior) {
			// 1-匀速排队, 则超时时间必填
			Integer maxQueueingTimeoutMs = reqVo.getMaxQueueingTimeoutMs();
			if (maxQueueingTimeoutMs == null) {
				return Result.ofFail(-1, "maxQueueingTimeoutMs can't be null");
			}
			if (maxQueueingTimeoutMs < 0) {
				return Result.ofFail(-1, "invalid maxQueueingTimeoutMs: " + maxQueueingTimeoutMs);
			}
			entity.setMaxQueueingTimeoutMs(maxQueueingTimeoutMs);
		}

		Date date = new Date();
		entity.setGmtCreate(date);
		entity.setGmtModified(date);

		try {
			entity = repository.save(entity);
		}
		catch (Throwable throwable) {
			logger.error("add gateway flow rule error:", throwable);
			return Result.ofThrowable(-1, throwable);
		}

		if (!publishRules(app, ip, port)) {
			logger.warn("publish gateway flow rules fail after add");
		}

		return Result.ofSuccess(entity);
	}

	@PostMapping("/save.json")
	@AuthAction(AuthService.PrivilegeType.WRITE_RULE)
	public Result<GatewayFlowRuleEntity> updateFlowRule(@RequestBody UpdateFlowRuleReqVo reqVo) {

		String app = reqVo.getApp();
		if (StringUtil.isBlank(app)) {
			return Result.ofFail(-1, "app can't be null or empty");
		}

		Long id = reqVo.getId();
		if (id == null) {
			return Result.ofFail(-1, "id can't be null");
		}

		GatewayFlowRuleEntity entity = repository.findById(id);
		if (entity == null) {
			return Result.ofFail(-1, "gateway flow rule does not exist, id=" + id);
		}

		// 针对请求属性
		GatewayParamFlowItemVo paramItem = reqVo.getParamItem();
		if (paramItem != null) {
			GatewayParamFlowItemEntity itemEntity = new GatewayParamFlowItemEntity();
			entity.setParamItem(itemEntity);

			// 参数属性 0-ClientIP 1-Remote Host 2-Header 3-URL参数 4-Cookie
			Integer parseStrategy = paramItem.getParseStrategy();
			if (!Arrays.asList(PARAM_PARSE_STRATEGY_CLIENT_IP, PARAM_PARSE_STRATEGY_HOST, PARAM_PARSE_STRATEGY_HEADER,
					PARAM_PARSE_STRATEGY_URL_PARAM, PARAM_PARSE_STRATEGY_COOKIE).contains(parseStrategy)) {
				return Result.ofFail(-1, "invalid parseStrategy: " + parseStrategy);
			}
			itemEntity.setParseStrategy(paramItem.getParseStrategy());

			// 当参数属性为2-Header 3-URL参数 4-Cookie时，参数名称必填
			if (Arrays.asList(PARAM_PARSE_STRATEGY_HEADER, PARAM_PARSE_STRATEGY_URL_PARAM, PARAM_PARSE_STRATEGY_COOKIE)
					.contains(parseStrategy)) {
				// 参数名称
				String fieldName = paramItem.getFieldName();
				if (StringUtil.isBlank(fieldName)) {
					return Result.ofFail(-1, "fieldName can't be null or empty");
				}
				itemEntity.setFieldName(paramItem.getFieldName());
			}

			String pattern = paramItem.getPattern();
			// 如果匹配串不为空，验证匹配模式
			if (StringUtil.isNotEmpty(pattern)) {
				itemEntity.setPattern(pattern);
				Integer matchStrategy = paramItem.getMatchStrategy();
				if (!Arrays
						.asList(PARAM_MATCH_STRATEGY_EXACT, PARAM_MATCH_STRATEGY_CONTAINS, PARAM_MATCH_STRATEGY_REGEX)
						.contains(matchStrategy)) {
					return Result.ofFail(-1, "invalid matchStrategy: " + matchStrategy);
				}
				itemEntity.setMatchStrategy(matchStrategy);
			}
		}
		else {
			entity.setParamItem(null);
		}

		// 阈值类型 0-线程数 1-QPS
		Integer grade = reqVo.getGrade();
		if (grade == null) {
			return Result.ofFail(-1, "grade can't be null");
		}
		if (!Arrays.asList(FLOW_GRADE_THREAD, FLOW_GRADE_QPS).contains(grade)) {
			return Result.ofFail(-1, "invalid grade: " + grade);
		}
		entity.setGrade(grade);

		// QPS阈值
		Double count = reqVo.getCount();
		if (count == null) {
			return Result.ofFail(-1, "count can't be null");
		}
		if (count < 0) {
			return Result.ofFail(-1, "count should be at lease zero");
		}
		entity.setCount(count);

		// 间隔
		Long interval = reqVo.getInterval();
		if (interval == null) {
			return Result.ofFail(-1, "interval can't be null");
		}
		if (interval <= 0) {
			return Result.ofFail(-1, "interval should be greater than zero");
		}
		entity.setInterval(interval);

		// 间隔单位
		Integer intervalUnit = reqVo.getIntervalUnit();
		if (intervalUnit == null) {
			return Result.ofFail(-1, "intervalUnit can't be null");
		}
		if (!Arrays.asList(INTERVAL_UNIT_SECOND, INTERVAL_UNIT_MINUTE, INTERVAL_UNIT_HOUR, INTERVAL_UNIT_DAY)
				.contains(intervalUnit)) {
			return Result.ofFail(-1, "Invalid intervalUnit: " + intervalUnit);
		}
		entity.setIntervalUnit(intervalUnit);

		// 流控方式 0-快速失败 2-匀速排队
		Integer controlBehavior = reqVo.getControlBehavior();
		if (controlBehavior == null) {
			return Result.ofFail(-1, "controlBehavior can't be null");
		}
		if (!Arrays.asList(CONTROL_BEHAVIOR_DEFAULT, CONTROL_BEHAVIOR_RATE_LIMITER).contains(controlBehavior)) {
			return Result.ofFail(-1, "invalid controlBehavior: " + controlBehavior);
		}
		entity.setControlBehavior(controlBehavior);

		if (CONTROL_BEHAVIOR_DEFAULT == controlBehavior) {
			// 0-快速失败, 则Burst size必填
			Integer burst = reqVo.getBurst();
			if (burst == null) {
				return Result.ofFail(-1, "burst can't be null");
			}
			if (burst < 0) {
				return Result.ofFail(-1, "invalid burst: " + burst);
			}
			entity.setBurst(burst);
		}
		else if (CONTROL_BEHAVIOR_RATE_LIMITER == controlBehavior) {
			// 2-匀速排队, 则超时时间必填
			Integer maxQueueingTimeoutMs = reqVo.getMaxQueueingTimeoutMs();
			if (maxQueueingTimeoutMs == null) {
				return Result.ofFail(-1, "maxQueueingTimeoutMs can't be null");
			}
			if (maxQueueingTimeoutMs < 0) {
				return Result.ofFail(-1, "invalid maxQueueingTimeoutMs: " + maxQueueingTimeoutMs);
			}
			entity.setMaxQueueingTimeoutMs(maxQueueingTimeoutMs);
		}

		Date date = new Date();
		entity.setGmtModified(date);

		try {
			entity = repository.save(entity);
		}
		catch (Throwable throwable) {
			logger.error("update gateway flow rule error:", throwable);
			return Result.ofThrowable(-1, throwable);
		}

		if (!publishRules(app, entity.getIp(), entity.getPort())) {
			logger.warn("publish gateway flow rules fail after update");
		}

		return Result.ofSuccess(entity);
	}

	@PostMapping("/delete.json")
	@AuthAction(AuthService.PrivilegeType.DELETE_RULE)
	public Result<Long> deleteFlowRule(Long id) {

		if (id == null) {
			return Result.ofFail(-1, "id can't be null");
		}

		GatewayFlowRuleEntity oldEntity = repository.findById(id);
		if (oldEntity == null) {
			return Result.ofSuccess(null);
		}

		try {
			repository.delete(id);
		}
		catch (Throwable throwable) {
			logger.error("delete gateway flow rule error:", throwable);
			return Result.ofThrowable(-1, throwable);
		}

		if (!publishRules(oldEntity.getApp(), oldEntity.getIp(), oldEntity.getPort())) {
			logger.warn("publish gateway flow rules fail after delete");
		}

		return Result.ofSuccess(id);
	}

	private boolean publishRules(String app, String ip, Integer port) {
		List<GatewayFlowRuleEntity> rules = repository.findAllByMachine(MachineInfo.of(app, ip, port));
		return sentinelApiClient.modifyGatewayFlowRules(app, ip, port, rules);
	}

}
