/*
 * 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.shardingsphere.ui.servcie.impl;

import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import org.apache.shardingsphere.governance.core.registry.RegistryCenterNodeStatus;
import org.apache.shardingsphere.governance.core.yaml.config.YamlConfigurationConverter;
import org.apache.shardingsphere.infra.config.RuleConfiguration;
import org.apache.shardingsphere.readwrite.splitting.api.ReadWriteSplittingRuleConfiguration;
import org.apache.shardingsphere.readwrite.splitting.api.rule.ReadWriteSplittingDataSourceRuleConfiguration;
import org.apache.shardingsphere.ui.common.dto.InstanceDTO;
import org.apache.shardingsphere.ui.common.dto.ReadDataSourceDTO;
import org.apache.shardingsphere.ui.servcie.GovernanceService;
import org.apache.shardingsphere.ui.servcie.RegistryCenterService;
import org.apache.shardingsphere.ui.servcie.ShardingSchemaService;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;

/**
 * Implementation of governance operation service.
 */
@Service
public final class GovernanceServiceImpl implements GovernanceService {
    
    @Resource
    private RegistryCenterService registryCenterService;
    
    @Resource
    private ShardingSchemaService shardingSchemaService;
    
    @Override
    public Collection<InstanceDTO> getALLInstance() {
        List<String> instanceIds = registryCenterService.getActivatedRegistryCenter().getChildrenKeys(getInstancesNodeFullRootPath());
        Collection<InstanceDTO> result = new ArrayList<>(instanceIds.size());
        for (String instanceId : instanceIds) {
            String value = registryCenterService.getActivatedRegistryCenter().get(registryCenterService.getActivatedStateNode().getProxyNodePath(instanceId));
            result.add(new InstanceDTO(instanceId, !RegistryCenterNodeStatus.DISABLED.toString().equalsIgnoreCase(value)));
        }
        return result;
    }
    
    @Override
    public void updateInstanceStatus(final String instanceId, final boolean enabled) {
        String value = enabled ? "" : RegistryCenterNodeStatus.DISABLED.toString();
        registryCenterService.getActivatedRegistryCenter().persist(registryCenterService.getActivatedStateNode().getProxyNodePath(instanceId), value);
    }
    
    @Override
    public Collection<ReadDataSourceDTO> getAllReadDataSource() {
        Collection<ReadDataSourceDTO> result = new ArrayList<>();
        for (String schemaName : shardingSchemaService.getAllSchemaNames()) {
            String configData = shardingSchemaService.getRuleConfiguration(schemaName);
            if (StringUtils.isEmpty(configData)) {
                continue;
            }
            if (configData.contains("!SHARDING")) {
                handleShardingRuleConfiguration(result, configData, schemaName);
            } else if (configData.contains("!READ_WRITE_SPLITTING")) {
                handleMasterSlaveRuleConfiguration(result, configData, schemaName);
            }
        }
        return result;
    }
    
    @Override
    public void updateReadDataSourceStatus(final String schemaNames, final String readDataSourceName, final boolean enabled) {
        String value = enabled ? "" : RegistryCenterNodeStatus.DISABLED.toString();
        registryCenterService.getActivatedRegistryCenter().persist(registryCenterService.getActivatedStateNode().getDataSourcePath(schemaNames, readDataSourceName), value);
    }
    
    private String getInstancesNodeFullRootPath() {
        String result = registryCenterService.getActivatedStateNode().getProxyNodePath("");
        return result.substring(0, result.length() - 1);
    }
    
    private void handleShardingRuleConfiguration(final Collection<ReadDataSourceDTO> readDataSourceDTOS, final String configData, final String schemaName) {
        Collection<RuleConfiguration> configurations = YamlConfigurationConverter.convertRuleConfigurations(configData);
        Collection<ReadWriteSplittingRuleConfiguration> readWriteSplittingRuleConfigurations = configurations.stream().filter(
            config -> config instanceof ReadWriteSplittingRuleConfiguration).map(config -> (ReadWriteSplittingRuleConfiguration) config).collect(Collectors.toList());
        for (ReadWriteSplittingRuleConfiguration readWriteSplittingRuleConfiguration : readWriteSplittingRuleConfigurations) {
            addSlaveDataSource(readDataSourceDTOS, readWriteSplittingRuleConfiguration, schemaName);
        }
    }
    
    private void handleMasterSlaveRuleConfiguration(final Collection<ReadDataSourceDTO> readDataSourceDTOS, final String configData, final String schemaName) {
        ReadWriteSplittingRuleConfiguration readWriteSplittingRuleConfiguration = loadPrimaryReadRuleConfiguration(configData);
        addSlaveDataSource(readDataSourceDTOS, readWriteSplittingRuleConfiguration, schemaName);
    }
    
    private ReadWriteSplittingRuleConfiguration loadPrimaryReadRuleConfiguration(final String configData) {
        Collection<RuleConfiguration> ruleConfigurations = YamlConfigurationConverter.convertRuleConfigurations(configData);
        Optional<ReadWriteSplittingRuleConfiguration> result = ruleConfigurations.stream().filter(
                each -> each instanceof ReadWriteSplittingRuleConfiguration).map(ruleConfiguration -> (ReadWriteSplittingRuleConfiguration) ruleConfiguration).findFirst();
        Preconditions.checkState(result.isPresent());
        return result.get();
    }
    
    private void addSlaveDataSource(final Collection<ReadDataSourceDTO> readDataSourceDTOS, final ReadWriteSplittingRuleConfiguration readWriteSplittingRuleConfiguration, final String schemaName) {
        Collection<String> disabledSchemaDataSourceNames = getDisabledSchemaDataSourceNames();
        for (ReadWriteSplittingDataSourceRuleConfiguration each : readWriteSplittingRuleConfiguration.getDataSources()) {
            readDataSourceDTOS.addAll(getReadDataSourceDTOS(schemaName, disabledSchemaDataSourceNames, each));
        }
    }
    
    private Collection<ReadDataSourceDTO> getReadDataSourceDTOS(final String schemaName, final Collection<String> disabledSchemaDataSourceNames, final ReadWriteSplittingDataSourceRuleConfiguration group) {
        Collection<ReadDataSourceDTO> result = new LinkedList<>();
        for (String each : group.getReadDataSourceNames()) {
            result.add(new ReadDataSourceDTO(schemaName, group.getWriteDataSourceName(), each, !disabledSchemaDataSourceNames.contains(schemaName + "." + each)));
        }
        return result;
    }
    
    private Collection<String> getDisabledSchemaDataSourceNames() {
        List<String> result = new ArrayList<>();
        List<String> schemaNames = registryCenterService.getActivatedRegistryCenter().getChildrenKeys(registryCenterService.getActivatedStateNode().getDataNodesPath());
        for (String schemaName : schemaNames) {
            List<String> dataSourceNames = registryCenterService.getActivatedRegistryCenter().getChildrenKeys(registryCenterService.getActivatedStateNode().getSchemaPath(schemaName));
            for (String dataSourceName : dataSourceNames) {
                String value = registryCenterService.getActivatedRegistryCenter().get(registryCenterService.getActivatedStateNode().getDataSourcePath(schemaName, dataSourceName));
                if (RegistryCenterNodeStatus.DISABLED.toString().equalsIgnoreCase(value)) {
                    result.add(Joiner.on(".").join(schemaName, dataSourceName));
                }
            }
        }
        return result;
    }
}