/*
 * 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 org.apache.kafka.clients.admin.internals;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;

import org.apache.kafka.clients.admin.ConsumerGroupDescription;
import org.apache.kafka.clients.admin.MemberAssignment;
import org.apache.kafka.clients.admin.MemberDescription;
import org.apache.kafka.clients.consumer.ConsumerPartitionAssignor.Assignment;
import org.apache.kafka.clients.consumer.internals.ConsumerProtocol;
import org.apache.kafka.common.ConsumerGroupState;
import org.apache.kafka.common.Node;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.acl.AclOperation;
import org.apache.kafka.common.message.DescribeGroupsRequestData;
import org.apache.kafka.common.message.DescribeGroupsResponseData.DescribedGroup;
import org.apache.kafka.common.message.DescribeGroupsResponseData.DescribedGroupMember;
import org.apache.kafka.common.protocol.Errors;
import org.apache.kafka.common.requests.AbstractResponse;
import org.apache.kafka.common.requests.DescribeGroupsRequest;
import org.apache.kafka.common.requests.DescribeGroupsResponse;
import org.apache.kafka.common.requests.FindCoordinatorRequest;
import org.apache.kafka.common.requests.MetadataResponse;
import org.apache.kafka.common.requests.FindCoordinatorRequest.CoordinatorType;
import org.apache.kafka.common.utils.LogContext;
import org.apache.kafka.common.utils.Utils;
import org.slf4j.Logger;

public class DescribeConsumerGroupsHandler implements AdminApiHandler<CoordinatorKey, ConsumerGroupDescription> {

    private final boolean includeAuthorizedOperations;
    private final Logger log;
    private final AdminApiLookupStrategy<CoordinatorKey> lookupStrategy;

    public DescribeConsumerGroupsHandler(
        boolean includeAuthorizedOperations,
        LogContext logContext
    ) {
        this.includeAuthorizedOperations = includeAuthorizedOperations;
        this.log = logContext.logger(DescribeConsumerGroupsHandler.class);
        this.lookupStrategy = new CoordinatorStrategy(CoordinatorType.GROUP, logContext);
    }

    private static Set<CoordinatorKey> buildKeySet(Collection<String> groupIds) {
        return groupIds.stream()
            .map(CoordinatorKey::byGroupId)
            .collect(Collectors.toSet());
    }

    public static AdminApiFuture.SimpleAdminApiFuture<CoordinatorKey, ConsumerGroupDescription> newFuture(
        Collection<String> groupIds
    ) {
        return AdminApiFuture.forKeys(buildKeySet(groupIds));
    }

    @Override
    public String apiName() {
        return "describeGroups";
    }

    @Override
    public AdminApiLookupStrategy<CoordinatorKey> lookupStrategy() {
        return lookupStrategy;
    }

    @Override
    public DescribeGroupsRequest.Builder buildRequest(int coordinatorId, Set<CoordinatorKey> keys) {
        List<String> groupIds = keys.stream().map(key -> {
            if (key.type != FindCoordinatorRequest.CoordinatorType.GROUP) {
                throw new IllegalArgumentException("Invalid transaction coordinator key " + key +
                    " when building `DescribeGroups` request");
            }
            return key.idValue;
        }).collect(Collectors.toList());
        DescribeGroupsRequestData data = new DescribeGroupsRequestData()
            .setGroups(groupIds)
            .setIncludeAuthorizedOperations(includeAuthorizedOperations);
        return new DescribeGroupsRequest.Builder(data);
    }

    @Override
    public ApiResult<CoordinatorKey, ConsumerGroupDescription> handleResponse(
        Node coordinator,
        Set<CoordinatorKey> groupIds,
        AbstractResponse abstractResponse
    ) {
        final DescribeGroupsResponse response = (DescribeGroupsResponse) abstractResponse;
        final Map<CoordinatorKey, ConsumerGroupDescription> completed = new HashMap<>();
        final Map<CoordinatorKey, Throwable> failed = new HashMap<>();
        final Set<CoordinatorKey> groupsToUnmap = new HashSet<>();

        for (DescribedGroup describedGroup : response.data().groups()) {
            CoordinatorKey groupIdKey = CoordinatorKey.byGroupId(describedGroup.groupId());
            Errors error = Errors.forCode(describedGroup.errorCode());
            if (error != Errors.NONE) {
                handleError(groupIdKey, error, failed, groupsToUnmap);
                continue;
            }
            final String protocolType = describedGroup.protocolType();
            if (protocolType.equals(ConsumerProtocol.PROTOCOL_TYPE) || protocolType.isEmpty()) {
                final List<DescribedGroupMember> members = describedGroup.members();
                final List<MemberDescription> memberDescriptions = new ArrayList<>(members.size());
                final Set<AclOperation> authorizedOperations = validAclOperations(describedGroup.authorizedOperations());
                for (DescribedGroupMember groupMember : members) {
                    Set<TopicPartition> partitions = Collections.emptySet();
                    if (groupMember.memberAssignment().length > 0) {
                        final Assignment assignment = ConsumerProtocol.
                            deserializeAssignment(ByteBuffer.wrap(groupMember.memberAssignment()));
                        partitions = new HashSet<>(assignment.partitions());
                    }
                    memberDescriptions.add(new MemberDescription(
                        groupMember.memberId(),
                        Optional.ofNullable(groupMember.groupInstanceId()),
                        groupMember.clientId(),
                        groupMember.clientHost(),
                        new MemberAssignment(partitions)));
                }
                final ConsumerGroupDescription consumerGroupDescription =
                    new ConsumerGroupDescription(groupIdKey.idValue, protocolType.isEmpty(),
                        memberDescriptions,
                        describedGroup.protocolData(),
                        ConsumerGroupState.parse(describedGroup.groupState()),
                        coordinator,
                        authorizedOperations);
                completed.put(groupIdKey, consumerGroupDescription);
            } else {
                failed.put(groupIdKey, new IllegalArgumentException(
                    String.format("GroupId %s is not a consumer group (%s).",
                        groupIdKey.idValue, protocolType)));
            }
        }

        return new ApiResult<>(completed, failed, new ArrayList<>(groupsToUnmap));
    }

    private void handleError(
        CoordinatorKey groupId,
        Errors error,
        Map<CoordinatorKey, Throwable> failed,
        Set<CoordinatorKey> groupsToUnmap
    ) {
        switch (error) {
            case GROUP_AUTHORIZATION_FAILED:
                log.debug("`DescribeGroups` request for group id {} failed due to error {}", groupId.idValue, error);
                failed.put(groupId, error.exception());
                break;

            case COORDINATOR_LOAD_IN_PROGRESS:
                // If the coordinator is in the middle of loading, then we just need to retry
                log.debug("`DescribeGroups` request for group id {} failed because the coordinator " +
                    "is still in the process of loading state. Will retry", groupId.idValue);
                break;

            case COORDINATOR_NOT_AVAILABLE:
            case NOT_COORDINATOR:
                // If the coordinator is unavailable or there was a coordinator change, then we unmap
                // the key so that we retry the `FindCoordinator` request
                log.debug("`DescribeGroups` request for group id {} returned error {}. " +
                    "Will attempt to find the coordinator again and retry", groupId.idValue, error);
                groupsToUnmap.add(groupId);
                break;

            default:
                log.error("`DescribeGroups` request for group id {} failed due to unexpected error {}", groupId.idValue, error);
                failed.put(groupId, error.exception());
        }
    }

    private Set<AclOperation> validAclOperations(final int authorizedOperations) {
        if (authorizedOperations == MetadataResponse.AUTHORIZED_OPERATIONS_OMITTED) {
            return null;
        }
        return Utils.from32BitField(authorizedOperations)
            .stream()
            .map(AclOperation::fromCode)
            .filter(operation -> operation != AclOperation.UNKNOWN
                && operation != AclOperation.ALL
                && operation != AclOperation.ANY)
            .collect(Collectors.toSet());
    }

}
