/*
 * 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.nacos.security.nacos.roles;

import com.alibaba.nacos.config.server.auth.PermissionInfo;
import com.alibaba.nacos.config.server.auth.PermissionPersistService;
import com.alibaba.nacos.config.server.auth.RoleInfo;
import com.alibaba.nacos.config.server.auth.RolePersistService;
import com.alibaba.nacos.config.server.model.Page;
import com.alibaba.nacos.security.nacos.NacosAuthConfig;
import com.alibaba.nacos.security.nacos.users.NacosUserDetailsServiceImpl;
import com.alibaba.nacos.core.auth.AuthConfigs;
import com.alibaba.nacos.core.auth.Permission;
import com.alibaba.nacos.core.utils.Loggers;
import io.jsonwebtoken.lang.Collections;
import org.apache.commons.lang3.StringUtils;
import org.apache.mina.util.ConcurrentHashSet;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Pattern;

/**
 * Nacos builtin role service.
 *
 * @author nkorange
 * @since 1.2.0
 */
@Service
public class NacosRoleServiceImpl {

	public static final String GLOBAL_ADMIN_ROLE = "ROLE_ADMIN";

	@Autowired
	private AuthConfigs authConfigs;

	@Autowired
	private RolePersistService rolePersistService;

	@Autowired
	private NacosUserDetailsServiceImpl userDetailsService;

	@Autowired
	private PermissionPersistService permissionPersistService;

	private volatile Set<String> roleSet = new ConcurrentHashSet<>();

	private volatile Map<String, List<RoleInfo>> roleInfoMap = new ConcurrentHashMap<>();

	private volatile Map<String, List<PermissionInfo>> permissionInfoMap = new ConcurrentHashMap<>();

	@Scheduled(initialDelay = 5000, fixedDelay = 15000)
	private void reload() {
		try {
			Page<RoleInfo> roleInfoPage = rolePersistService.getRolesByUserName(StringUtils.EMPTY, 1,
					Integer.MAX_VALUE);
			if (roleInfoPage == null) {
				return;
			}
			Set<String> tmpRoleSet = new HashSet<>(16);
			Map<String, List<RoleInfo>> tmpRoleInfoMap = new ConcurrentHashMap<>(16);
			for (RoleInfo roleInfo : roleInfoPage.getPageItems()) {
				if (!tmpRoleInfoMap.containsKey(roleInfo.getUsername())) {
					tmpRoleInfoMap.put(roleInfo.getUsername(), new ArrayList<>());
				}
				tmpRoleInfoMap.get(roleInfo.getUsername()).add(roleInfo);
				tmpRoleSet.add(roleInfo.getRole());
			}

			Map<String, List<PermissionInfo>> tmpPermissionInfoMap = new ConcurrentHashMap<>(16);
			for (String role : tmpRoleSet) {
				Page<PermissionInfo> permissionInfoPage = permissionPersistService.getPermissions(role, 1,
						Integer.MAX_VALUE);
				tmpPermissionInfoMap.put(role, permissionInfoPage.getPageItems());
			}

			roleSet = tmpRoleSet;
			roleInfoMap = tmpRoleInfoMap;
			permissionInfoMap = tmpPermissionInfoMap;
		}
		catch (Exception e) {
			Loggers.AUTH.warn("[LOAD-ROLES] load failed", e);
		}
	}

	/**
	 * Determine if the user has permission of the resource.
	 *
	 * <p>
	 * Note if the user has many roles, this method returns true if any one role of the
	 * user has the desired permission.
	 * @param username user info
	 * @param permission permission to auth
	 * @return true if granted, false otherwise
	 */
	public boolean hasPermission(String username, Permission permission) {

		List<RoleInfo> roleInfoList = getRoles(username);
		if (Collections.isEmpty(roleInfoList)) {
			return false;
		}

		// Global admin pass:
		for (RoleInfo roleInfo : roleInfoList) {
			if (GLOBAL_ADMIN_ROLE.equals(roleInfo.getRole())) {
				return true;
			}
		}

		// Old global admin can pass resource 'console/':
		if (permission.getResource().startsWith(NacosAuthConfig.CONSOLE_RESOURCE_NAME_PREFIX)) {
			return false;
		}

		// For other roles, use a pattern match to decide if pass or not.
		for (RoleInfo roleInfo : roleInfoList) {
			List<PermissionInfo> permissionInfoList = getPermissions(roleInfo.getRole());
			if (Collections.isEmpty(permissionInfoList)) {
				continue;
			}
			for (PermissionInfo permissionInfo : permissionInfoList) {
				String permissionResource = permissionInfo.getResource().replaceAll("\\*", ".*");
				String permissionAction = permissionInfo.getAction();
				if (permissionAction.contains(permission.getAction())
						&& Pattern.matches(permissionResource, permission.getResource())) {
					return true;
				}
			}
		}
		return false;
	}

	public List<RoleInfo> getRoles(String username) {
		List<RoleInfo> roleInfoList = roleInfoMap.get(username);
		if (!authConfigs.isCachingEnabled()) {
			Page<RoleInfo> roleInfoPage = getRolesFromDatabase(username, 1, Integer.MAX_VALUE);
			if (roleInfoPage != null) {
				roleInfoList = roleInfoPage.getPageItems();
			}
		}
		return roleInfoList;
	}

	public Page<RoleInfo> getRolesFromDatabase(String userName, int pageNo, int pageSize) {
		Page<RoleInfo> roles = rolePersistService.getRolesByUserName(userName, pageNo, pageSize);
		if (roles == null) {
			return new Page<>();
		}
		return roles;
	}

	public List<PermissionInfo> getPermissions(String role) {
		List<PermissionInfo> permissionInfoList = permissionInfoMap.get(role);
		if (!authConfigs.isCachingEnabled()) {
			Page<PermissionInfo> permissionInfoPage = getPermissionsFromDatabase(role, 1, Integer.MAX_VALUE);
			if (permissionInfoPage != null) {
				permissionInfoList = permissionInfoPage.getPageItems();
			}
		}
		return permissionInfoList;
	}

	public Page<PermissionInfo> getPermissionsByRoleFromDatabase(String role, int pageNo, int pageSize) {
		return permissionPersistService.getPermissions(role, pageNo, pageSize);
	}

	/**
	 * Add role.
	 * @param role role name
	 * @param username user name
	 */
	public void addRole(String role, String username) {
		if (userDetailsService.getUserFromDatabase(username) == null) {
			throw new IllegalArgumentException("user '" + username + "' not found!");
		}
		if (GLOBAL_ADMIN_ROLE.equals(role)) {
			throw new IllegalArgumentException("role '" + GLOBAL_ADMIN_ROLE + "' is not permitted to create!");
		}
		rolePersistService.addRole(role, username);
		roleSet.add(role);
	}

	public void deleteRole(String role, String userName) {
		rolePersistService.deleteRole(role, userName);
	}

	public void deleteRole(String role) {
		rolePersistService.deleteRole(role);
		roleSet.remove(role);
	}

	public Page<PermissionInfo> getPermissionsFromDatabase(String role, int pageNo, int pageSize) {
		Page<PermissionInfo> pageInfo = permissionPersistService.getPermissions(role, pageNo, pageSize);
		if (pageInfo == null) {
			return new Page<>();
		}
		return pageInfo;
	}

	/**
	 * Add permission.
	 * @param role role name
	 * @param resource resource
	 * @param action action
	 */
	public void addPermission(String role, String resource, String action) {
		if (!roleSet.contains(role)) {
			throw new IllegalArgumentException("role " + role + " not found!");
		}
		permissionPersistService.addPermission(role, resource, action);
	}

	public void deletePermission(String role, String resource, String action) {
		permissionPersistService.deletePermission(role, resource, action);
	}

}
