/**
    * 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.hadoop.hbase.quotas;
  
  import java.io.IOException;
  import java.util.HashSet;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.DoNotRetryIOException;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.MetaTableAccessor;
  import org.apache.hadoop.hbase.NamespaceDescriptor;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.master.MasterServices;
  import org.apache.hadoop.hbase.master.procedure.CreateTableProcedure;
  import org.apache.hadoop.hbase.namespace.NamespaceAuditor;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.SetQuotaRequest;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.SetQuotaResponse;
  import org.apache.hadoop.hbase.protobuf.generated.QuotaProtos.Quotas;
  import org.apache.hadoop.hbase.protobuf.generated.QuotaProtos.Throttle;
  import org.apache.hadoop.hbase.protobuf.generated.QuotaProtos.ThrottleRequest;
  import org.apache.hadoop.hbase.protobuf.generated.QuotaProtos.TimedQuota;
  
  /**
   * Master Quota Manager.
   * It is responsible for initialize the quota table on the first-run and
   * provide the admin operations to interact with the quota table.
   *
   * TODO: FUTURE: The master will be responsible to notify each RS of quota changes
   * and it will do the "quota aggregation" when the QuotaScope is CLUSTER.
   */
  @InterfaceAudience.Private
  @InterfaceStability.Evolving
  public class MasterQuotaManager implements RegionStateListener {
    private static final Log LOG = LogFactory.getLog(MasterQuotaManager.class);
  
    private final MasterServices masterServices;
    private NamedLock<String> namespaceLocks;
    private NamedLock<TableName> tableLocks;
    private NamedLock<String> userLocks;
    private boolean enabled = false;
    private NamespaceAuditor namespaceQuotaManager;
  
    public MasterQuotaManager(final MasterServices masterServices) {
      this.masterServices = masterServices;
    }
  
    public void start() throws IOException {
      // If the user doesn't want the quota support skip all the initializations.
      if (!QuotaUtil.isQuotaEnabled(masterServices.getConfiguration())) {
        LOG.info("Quota support disabled");
        return;
      }
  
      // Create the quota table if missing
      if (!MetaTableAccessor.tableExists(masterServices.getConnection(),
            QuotaUtil.QUOTA_TABLE_NAME)) {
        LOG.info("Quota table not found. Creating...");
        createQuotaTable();
      }
  
      LOG.info("Initializing quota support");
      namespaceLocks = new NamedLock<String>();
      tableLocks = new NamedLock<TableName>();
      userLocks = new NamedLock<String>();
  
      namespaceQuotaManager = new NamespaceAuditor(masterServices);
      namespaceQuotaManager.start();
      enabled = true;
    }
  
    public void stop() {
    }
  
    public boolean isQuotaEnabled() {
      return enabled && namespaceQuotaManager.isInitialized();
    }
  
    /* ==========================================================================
    *  Admin operations to manage the quota table
    */
   public SetQuotaResponse setQuota(final SetQuotaRequest req)
       throws IOException, InterruptedException {
     checkQuotaSupport();
 
     if (req.hasUserName()) {
       userLocks.lock(req.getUserName());
       try {
         if (req.hasTableName()) {
           setUserQuota(req.getUserName(), ProtobufUtil.toTableName(req.getTableName()), req);
         } else if (req.hasNamespace()) {
           setUserQuota(req.getUserName(), req.getNamespace(), req);
         } else {
           setUserQuota(req.getUserName(), req);
         }
       } finally {
         userLocks.unlock(req.getUserName());
       }
     } else if (req.hasTableName()) {
       TableName table = ProtobufUtil.toTableName(req.getTableName());
       tableLocks.lock(table);
       try {
         setTableQuota(table, req);
       } finally {
         tableLocks.unlock(table);
       }
     } else if (req.hasNamespace()) {
       namespaceLocks.lock(req.getNamespace());
       try {
         setNamespaceQuota(req.getNamespace(), req);
       } finally {
         namespaceLocks.unlock(req.getNamespace());
       }
     } else {
       throw new DoNotRetryIOException(
         new UnsupportedOperationException("a user, a table or a namespace must be specified"));
     }
     return SetQuotaResponse.newBuilder().build();
   }
 
   public void setUserQuota(final String userName, final SetQuotaRequest req)
       throws IOException, InterruptedException {
     setQuota(req, new SetQuotaOperations() {
       @Override
       public Quotas fetch() throws IOException {
         return QuotaUtil.getUserQuota(masterServices.getConnection(), userName);
       }
       @Override
       public void update(final Quotas quotas) throws IOException {
         QuotaUtil.addUserQuota(masterServices.getConnection(), userName, quotas);
       }
       @Override
       public void delete() throws IOException {
         QuotaUtil.deleteUserQuota(masterServices.getConnection(), userName);
       }
       @Override
       public void preApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().preSetUserQuota(userName, quotas);
       }
       @Override
       public void postApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().postSetUserQuota(userName, quotas);
       }
     });
   }
 
   public void setUserQuota(final String userName, final TableName table,
       final SetQuotaRequest req) throws IOException, InterruptedException {
     setQuota(req, new SetQuotaOperations() {
       @Override
       public Quotas fetch() throws IOException {
         return QuotaUtil.getUserQuota(masterServices.getConnection(), userName, table);
       }
       @Override
       public void update(final Quotas quotas) throws IOException {
         QuotaUtil.addUserQuota(masterServices.getConnection(), userName, table, quotas);
       }
       @Override
       public void delete() throws IOException {
         QuotaUtil.deleteUserQuota(masterServices.getConnection(), userName, table);
       }
       @Override
       public void preApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().preSetUserQuota(userName, table, quotas);
       }
       @Override
       public void postApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().postSetUserQuota(userName, table, quotas);
       }
     });
   }
 
   public void setUserQuota(final String userName, final String namespace,
       final SetQuotaRequest req) throws IOException, InterruptedException {
     setQuota(req, new SetQuotaOperations() {
       @Override
       public Quotas fetch() throws IOException {
         return QuotaUtil.getUserQuota(masterServices.getConnection(), userName, namespace);
       }
       @Override
       public void update(final Quotas quotas) throws IOException {
         QuotaUtil.addUserQuota(masterServices.getConnection(), userName, namespace, quotas);
       }
       @Override
       public void delete() throws IOException {
         QuotaUtil.deleteUserQuota(masterServices.getConnection(), userName, namespace);
       }
       @Override
       public void preApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().preSetUserQuota(userName, namespace, quotas);
       }
       @Override
       public void postApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().postSetUserQuota(userName, namespace, quotas);
       }
     });
   }
 
   public void setTableQuota(final TableName table, final SetQuotaRequest req)
       throws IOException, InterruptedException {
     setQuota(req, new SetQuotaOperations() {
       @Override
       public Quotas fetch() throws IOException {
         return QuotaUtil.getTableQuota(masterServices.getConnection(), table);
       }
       @Override
       public void update(final Quotas quotas) throws IOException {
         QuotaUtil.addTableQuota(masterServices.getConnection(), table, quotas);
       }
       @Override
       public void delete() throws IOException {
         QuotaUtil.deleteTableQuota(masterServices.getConnection(), table);
       }
       @Override
       public void preApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().preSetTableQuota(table, quotas);
       }
       @Override
       public void postApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().postSetTableQuota(table, quotas);
       }
     });
   }
 
   public void setNamespaceQuota(final String namespace, final SetQuotaRequest req)
       throws IOException, InterruptedException {
     setQuota(req, new SetQuotaOperations() {
       @Override
       public Quotas fetch() throws IOException {
         return QuotaUtil.getNamespaceQuota(masterServices.getConnection(), namespace);
       }
       @Override
       public void update(final Quotas quotas) throws IOException {
         QuotaUtil.addNamespaceQuota(masterServices.getConnection(), namespace, quotas);
       }
       @Override
       public void delete() throws IOException {
         QuotaUtil.deleteNamespaceQuota(masterServices.getConnection(), namespace);
       }
       @Override
       public void preApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().preSetNamespaceQuota(namespace, quotas);
       }
       @Override
       public void postApply(final Quotas quotas) throws IOException {
         masterServices.getMasterCoprocessorHost().postSetNamespaceQuota(namespace, quotas);
       }
     });
   }
 
   public void setNamespaceQuota(NamespaceDescriptor desc) throws IOException {
     if (enabled) {
       this.namespaceQuotaManager.addNamespace(desc);
     }
   }
 
   public void removeNamespaceQuota(String namespace) throws IOException {
     if (enabled) {
       this.namespaceQuotaManager.deleteNamespace(namespace);
     }
   }
 
   private void setQuota(final SetQuotaRequest req, final SetQuotaOperations quotaOps)
       throws IOException, InterruptedException {
     if (req.hasRemoveAll() && req.getRemoveAll() == true) {
       quotaOps.preApply(null);
       quotaOps.delete();
       quotaOps.postApply(null);
       return;
     }
 
     // Apply quota changes
     Quotas quotas = quotaOps.fetch();
     quotaOps.preApply(quotas);
 
     Quotas.Builder builder = (quotas != null) ? quotas.toBuilder() : Quotas.newBuilder();
     if (req.hasThrottle()) applyThrottle(builder, req.getThrottle());
     if (req.hasBypassGlobals()) applyBypassGlobals(builder, req.getBypassGlobals());
 
     // Submit new changes
     quotas = builder.build();
     if (QuotaUtil.isEmptyQuota(quotas)) {
       quotaOps.delete();
     } else {
       quotaOps.update(quotas);
     }
     quotaOps.postApply(quotas);
   }
 
   public void checkNamespaceTableAndRegionQuota(TableName tName, int regions) throws IOException {
     if (enabled) {
       namespaceQuotaManager.checkQuotaToCreateTable(tName, regions);
     }
   }
   
   public void checkAndUpdateNamespaceRegionQuota(TableName tName, int regions) throws IOException {
     if (enabled) {
       namespaceQuotaManager.checkQuotaToUpdateRegion(tName, regions);
     }
   }
 
   public void onRegionMerged(HRegionInfo hri) throws IOException {
     if (enabled) {
       namespaceQuotaManager.updateQuotaForRegionMerge(hri);
     }
   }
 
   public void onRegionSplit(HRegionInfo hri) throws IOException {
     if (enabled) {
       namespaceQuotaManager.checkQuotaToSplitRegion(hri);
     }
   }
 
   /**
    * Remove table from namespace quota.
    *
    * @param tName - The table name to update quota usage.
    * @throws IOException Signals that an I/O exception has occurred.
    */
   public void removeTableFromNamespaceQuota(TableName tName) throws IOException {
     if (enabled) {
       namespaceQuotaManager.removeFromNamespaceUsage(tName);
     }
   }
 
   public NamespaceAuditor getNamespaceQuotaManager() {
     return this.namespaceQuotaManager;
   }
 
   private static interface SetQuotaOperations {
     Quotas fetch() throws IOException;
     void delete() throws IOException;
     void update(final Quotas quotas) throws IOException;
     void preApply(final Quotas quotas) throws IOException;
     void postApply(final Quotas quotas) throws IOException;
   }
 
   /* ==========================================================================
    *  Helpers to apply changes to the quotas
    */
   private void applyThrottle(final Quotas.Builder quotas, final ThrottleRequest req)
       throws IOException {
     Throttle.Builder throttle;
 
     if (req.hasType() && (req.hasTimedQuota() || quotas.hasThrottle())) {
       // Validate timed quota if present
       if (req.hasTimedQuota()) validateTimedQuota(req.getTimedQuota());
 
       // apply the new settings
       throttle = quotas.hasThrottle() ? quotas.getThrottle().toBuilder() : Throttle.newBuilder();
 
       switch (req.getType()) {
         case REQUEST_NUMBER:
           if (req.hasTimedQuota()) {
             throttle.setReqNum(req.getTimedQuota());
           } else {
             throttle.clearReqNum();
           }
           break;
         case REQUEST_SIZE:
           if (req.hasTimedQuota()) {
             throttle.setReqSize(req.getTimedQuota());
           } else {
             throttle.clearReqSize();
           }
           break;
         case WRITE_NUMBER:
           if (req.hasTimedQuota()) {
             throttle.setWriteNum(req.getTimedQuota());
           } else {
             throttle.clearWriteNum();
           }
           break;
         case WRITE_SIZE:
           if (req.hasTimedQuota()) {
             throttle.setWriteSize(req.getTimedQuota());
           } else {
             throttle.clearWriteSize();
           }
           break;
         case READ_NUMBER:
           if (req.hasTimedQuota()) {
             throttle.setReadNum(req.getTimedQuota());
           } else {
             throttle.clearReqNum();
           }
           break;
         case READ_SIZE:
           if (req.hasTimedQuota()) {
             throttle.setReadSize(req.getTimedQuota());
           } else {
             throttle.clearReadSize();
           }
           break;
       }
       quotas.setThrottle(throttle.build());
     } else {
       quotas.clearThrottle();
     }
   }
 
   private void applyBypassGlobals(final Quotas.Builder quotas, boolean bypassGlobals) {
     if (bypassGlobals) {
       quotas.setBypassGlobals(bypassGlobals);
     } else {
       quotas.clearBypassGlobals();
     }
   }
 
   private void validateTimedQuota(final TimedQuota timedQuota) throws IOException {
     if (timedQuota.getSoftLimit() < 1) {
       throw new DoNotRetryIOException(new UnsupportedOperationException(
           "The throttle limit must be greater then 0, got " + timedQuota.getSoftLimit()));
     }
   }
 
   /* ==========================================================================
    *  Helpers
    */
 
   private void checkQuotaSupport() throws IOException {
     if (!enabled) {
       throw new DoNotRetryIOException(
         new UnsupportedOperationException("quota support disabled"));
     }
   }
 
   private void createQuotaTable() throws IOException {
     HRegionInfo newRegions[] = new HRegionInfo[] {
       new HRegionInfo(QuotaUtil.QUOTA_TABLE_NAME)
     };
 
     masterServices.getMasterProcedureExecutor()
       .submitProcedure(new CreateTableProcedure(
           masterServices.getMasterProcedureExecutor().getEnvironment(),
           QuotaUtil.QUOTA_TABLE_DESC,
           newRegions));
   }
 
   private static class NamedLock<T> {
     private HashSet<T> locks = new HashSet<T>();
 
     public void lock(final T name) throws InterruptedException {
       synchronized (locks) {
         while (locks.contains(name)) {
           locks.wait();
         }
         locks.add(name);
       }
     }
 
     public void unlock(final T name) {
       synchronized (locks) {
         locks.remove(name);
         locks.notifyAll();
       }
     }
   }
 
   @Override
   public void onRegionSplitReverted(HRegionInfo hri) throws IOException {
     if (enabled) {
       this.namespaceQuotaManager.removeRegionFromNamespaceUsage(hri);
     }
   }
 }