/*
 * 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;

import java.util.Date;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

import com.alibaba.csp.sentinel.dashboard.auth.AuthAction;
import com.alibaba.csp.sentinel.dashboard.client.CommandNotFoundException;
import com.alibaba.csp.sentinel.dashboard.client.SentinelApiClient;
import com.alibaba.csp.sentinel.dashboard.discovery.AppManagement;
import com.alibaba.csp.sentinel.dashboard.discovery.MachineInfo;
import com.alibaba.csp.sentinel.dashboard.auth.AuthService;
import com.alibaba.csp.sentinel.dashboard.auth.AuthService.PrivilegeType;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.util.StringUtil;
import com.alibaba.csp.sentinel.dashboard.datasource.entity.SentinelVersion;
import com.alibaba.csp.sentinel.dashboard.datasource.entity.rule.ParamFlowRuleEntity;
import com.alibaba.csp.sentinel.dashboard.domain.Result;
import com.alibaba.csp.sentinel.dashboard.repository.rule.RuleRepository;
import com.alibaba.csp.sentinel.dashboard.util.VersionUtils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author Eric Zhao
 * @since 0.2.1
 */
@RestController
@RequestMapping(value = "/paramFlow")
public class ParamFlowRuleController {

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

	@Autowired
	private SentinelApiClient sentinelApiClient;

	@Autowired
	private AppManagement appManagement;

	@Autowired
	private RuleRepository<ParamFlowRuleEntity, Long> repository;

	private boolean checkIfSupported(String app, String ip, int port) {
		try {
			return Optional.ofNullable(appManagement.getDetailApp(app)).flatMap(e -> e.getMachine(ip, port))
					.flatMap(m -> VersionUtils.parseVersion(m.getVersion()).map(v -> v.greaterOrEqual(version020)))
					.orElse(true);
			// If error occurred or cannot retrieve machine info, return true.
		}
		catch (Exception ex) {
			return true;
		}
	}

	@GetMapping("/rules")
	@AuthAction(PrivilegeType.READ_RULE)
	public Result<List<ParamFlowRuleEntity>> apiQueryAllRulesForMachine(@RequestParam String app,
			@RequestParam String ip, @RequestParam Integer port) {
		if (StringUtil.isEmpty(app)) {
			return Result.ofFail(-1, "app cannot be null or empty");
		}
		if (StringUtil.isEmpty(ip)) {
			return Result.ofFail(-1, "ip cannot be null or empty");
		}
		if (port == null || port <= 0) {
			return Result.ofFail(-1, "Invalid parameter: port");
		}
		if (!checkIfSupported(app, ip, port)) {
			return unsupportedVersion();
		}
		try {
			return sentinelApiClient.fetchParamFlowRulesOfMachine(app, ip, port).thenApply(repository::saveAll)
					.thenApply(Result::ofSuccess).get();
		}
		catch (ExecutionException ex) {
			logger.error("Error when querying parameter flow rules", ex.getCause());
			if (isNotSupported(ex.getCause())) {
				return unsupportedVersion();
			}
			else {
				return Result.ofThrowable(-1, ex.getCause());
			}
		}
		catch (Throwable throwable) {
			logger.error("Error when querying parameter flow rules", throwable);
			return Result.ofFail(-1, throwable.getMessage());
		}
	}

	private boolean isNotSupported(Throwable ex) {
		return ex instanceof CommandNotFoundException;
	}

	@PostMapping("/rule")
	@AuthAction(AuthService.PrivilegeType.WRITE_RULE)
	public Result<ParamFlowRuleEntity> apiAddParamFlowRule(@RequestBody ParamFlowRuleEntity entity) {
		Result<ParamFlowRuleEntity> checkResult = checkEntityInternal(entity);
		if (checkResult != null) {
			return checkResult;
		}
		if (!checkIfSupported(entity.getApp(), entity.getIp(), entity.getPort())) {
			return unsupportedVersion();
		}
		entity.setId(null);
		entity.getRule().setResource(entity.getResource().trim());
		Date date = new Date();
		entity.setGmtCreate(date);
		entity.setGmtModified(date);
		try {
			entity = repository.save(entity);
			publishRules(entity.getApp(), entity.getIp(), entity.getPort()).get();
			return Result.ofSuccess(entity);
		}
		catch (ExecutionException ex) {
			logger.error("Error when adding new parameter flow rules", ex.getCause());
			if (isNotSupported(ex.getCause())) {
				return unsupportedVersion();
			}
			else {
				return Result.ofThrowable(-1, ex.getCause());
			}
		}
		catch (Throwable throwable) {
			logger.error("Error when adding new parameter flow rules", throwable);
			return Result.ofFail(-1, throwable.getMessage());
		}
	}

	private <R> Result<R> checkEntityInternal(ParamFlowRuleEntity entity) {
		if (entity == null) {
			return Result.ofFail(-1, "bad rule body");
		}
		if (StringUtil.isBlank(entity.getApp())) {
			return Result.ofFail(-1, "app can't be null or empty");
		}
		if (StringUtil.isBlank(entity.getIp())) {
			return Result.ofFail(-1, "ip can't be null or empty");
		}
		if (entity.getPort() == null || entity.getPort() <= 0) {
			return Result.ofFail(-1, "port can't be null");
		}
		if (entity.getRule() == null) {
			return Result.ofFail(-1, "rule can't be null");
		}
		if (StringUtil.isBlank(entity.getResource())) {
			return Result.ofFail(-1, "resource name cannot be null or empty");
		}
		if (entity.getCount() < 0) {
			return Result.ofFail(-1, "count should be valid");
		}
		if (entity.getGrade() != RuleConstant.FLOW_GRADE_QPS) {
			return Result.ofFail(-1, "Unknown mode (blockGrade) for parameter flow control");
		}
		if (entity.getParamIdx() == null || entity.getParamIdx() < 0) {
			return Result.ofFail(-1, "paramIdx should be valid");
		}
		if (entity.getDurationInSec() <= 0) {
			return Result.ofFail(-1, "durationInSec should be valid");
		}
		if (entity.getControlBehavior() < 0) {
			return Result.ofFail(-1, "controlBehavior should be valid");
		}
		return null;
	}

	@PutMapping("/rule/{id}")
	@AuthAction(AuthService.PrivilegeType.WRITE_RULE)
	public Result<ParamFlowRuleEntity> apiUpdateParamFlowRule(@PathVariable("id") Long id,
			@RequestBody ParamFlowRuleEntity entity) {
		if (id == null || id <= 0) {
			return Result.ofFail(-1, "Invalid id");
		}
		ParamFlowRuleEntity oldEntity = repository.findById(id);
		if (oldEntity == null) {
			return Result.ofFail(-1, "id " + id + " does not exist");
		}

		Result<ParamFlowRuleEntity> checkResult = checkEntityInternal(entity);
		if (checkResult != null) {
			return checkResult;
		}
		if (!checkIfSupported(entity.getApp(), entity.getIp(), entity.getPort())) {
			return unsupportedVersion();
		}
		entity.setId(id);
		Date date = new Date();
		entity.setGmtCreate(oldEntity.getGmtCreate());
		entity.setGmtModified(date);
		try {
			entity = repository.save(entity);
			publishRules(entity.getApp(), entity.getIp(), entity.getPort()).get();
			return Result.ofSuccess(entity);
		}
		catch (ExecutionException ex) {
			logger.error("Error when updating parameter flow rules, id=" + id, ex.getCause());
			if (isNotSupported(ex.getCause())) {
				return unsupportedVersion();
			}
			else {
				return Result.ofThrowable(-1, ex.getCause());
			}
		}
		catch (Throwable throwable) {
			logger.error("Error when updating parameter flow rules, id=" + id, throwable);
			return Result.ofFail(-1, throwable.getMessage());
		}
	}

	@DeleteMapping("/rule/{id}")
	@AuthAction(PrivilegeType.DELETE_RULE)
	public Result<Long> apiDeleteRule(@PathVariable("id") Long id) {
		if (id == null) {
			return Result.ofFail(-1, "id cannot be null");
		}
		ParamFlowRuleEntity oldEntity = repository.findById(id);
		if (oldEntity == null) {
			return Result.ofSuccess(null);
		}

		try {
			repository.delete(id);
			publishRules(oldEntity.getApp(), oldEntity.getIp(), oldEntity.getPort()).get();
			return Result.ofSuccess(id);
		}
		catch (ExecutionException ex) {
			logger.error("Error when deleting parameter flow rules", ex.getCause());
			if (isNotSupported(ex.getCause())) {
				return unsupportedVersion();
			}
			else {
				return Result.ofThrowable(-1, ex.getCause());
			}
		}
		catch (Throwable throwable) {
			logger.error("Error when deleting parameter flow rules", throwable);
			return Result.ofFail(-1, throwable.getMessage());
		}
	}

	private CompletableFuture<Void> publishRules(String app, String ip, Integer port) {
		List<ParamFlowRuleEntity> rules = repository.findAllByMachine(MachineInfo.of(app, ip, port));
		return sentinelApiClient.setParamFlowRuleOfMachine(app, ip, port, rules);
	}

	private <R> Result<R> unsupportedVersion() {
		return Result.ofFail(4041,
				"Sentinel client not supported for parameter flow control (unsupported version or dependency absent)");
	}

	private final SentinelVersion version020 = new SentinelVersion().setMinorVersion(2);

}
