/*
    * 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.eclipse.aether.internal.impl.synccontext.named;
  
  import java.util.ArrayDeque;
  import java.util.Collection;
  import java.util.Deque;
  import java.util.concurrent.TimeUnit;
  import java.util.stream.Collectors;
  
  import org.eclipse.aether.ConfigurationProperties;
  import org.eclipse.aether.RepositorySystemSession;
  import org.eclipse.aether.SyncContext;
  import org.eclipse.aether.artifact.Artifact;
  import org.eclipse.aether.metadata.Metadata;
  import org.eclipse.aether.named.NamedLock;
  import org.eclipse.aether.named.NamedLockFactory;
  import org.eclipse.aether.named.NamedLockKey;
  import org.eclipse.aether.named.providers.FileLockNamedLockFactory;
  import org.eclipse.aether.util.ConfigUtils;
  import org.eclipse.aether.util.artifact.ArtifactIdUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Adapter to adapt {@link NamedLockFactory} and {@link NamedLock} to {@link SyncContext}.
   */
  public final class NamedLockFactoryAdapter {
      public static final String CONFIG_PROPS_PREFIX = ConfigurationProperties.PREFIX_SYNC_CONTEXT + "named.";
  
      /**
       * The maximum of time amount to be blocked to obtain lock.
       *
       * @since 1.7.0
       * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
       * @configurationType {@link java.lang.Long}
       * @configurationDefaultValue {@link #DEFAULT_TIME}
       */
      public static final String CONFIG_PROP_TIME = CONFIG_PROPS_PREFIX + "time";
  
      public static final long DEFAULT_TIME = 900L;
  
      /**
       * The unit of maximum time amount to be blocked to obtain lock. Use TimeUnit enum names.
       *
       * @since 1.7.0
       * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
       * @configurationType {@link java.lang.String}
       * @configurationDefaultValue {@link #DEFAULT_TIME_UNIT}
       */
      public static final String CONFIG_PROP_TIME_UNIT = CONFIG_PROPS_PREFIX + "time.unit";
  
      public static final String DEFAULT_TIME_UNIT = "SECONDS";
  
      /**
       * The amount of retries on time-out.
       *
       * @since 1.7.0
       * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
       * @configurationType {@link java.lang.Integer}
       * @configurationDefaultValue {@link #DEFAULT_RETRY}
       */
      public static final String CONFIG_PROP_RETRY = CONFIG_PROPS_PREFIX + "retry";
  
      public static final int DEFAULT_RETRY = 1;
  
      /**
       * The amount of milliseconds to wait between retries on time-out.
       *
       * @since 1.7.0
       * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
       * @configurationType {@link java.lang.Long}
       * @configurationDefaultValue {@link #DEFAULT_RETRY_WAIT}
       */
      public static final String CONFIG_PROP_RETRY_WAIT = CONFIG_PROPS_PREFIX + "retry.wait";
  
      public static final long DEFAULT_RETRY_WAIT = 200L;
  
      private final NameMapper nameMapper;
  
      private final NamedLockFactory namedLockFactory;
 
     public NamedLockFactoryAdapter(final NameMapper nameMapper, final NamedLockFactory namedLockFactory) {
         this.nameMapper = requireNonNull(nameMapper);
         this.namedLockFactory = requireNonNull(namedLockFactory);
         // TODO: this is ad-hoc "validation", experimental and likely to change
         if (this.namedLockFactory instanceof FileLockNamedLockFactory && !this.nameMapper.isFileSystemFriendly()) {
             throw new IllegalArgumentException(
                     "Misconfiguration: FileLockNamedLockFactory lock factory requires FS friendly NameMapper");
         }
     }
 
     public SyncContext newInstance(final RepositorySystemSession session, final boolean shared) {
         return new AdaptedLockSyncContext(session, shared, nameMapper, namedLockFactory);
     }
 
     /**
      * @since 1.9.1
      */
     public NameMapper getNameMapper() {
         return nameMapper;
     }
 
     /**
      * @since 1.9.1
      */
     public NamedLockFactory getNamedLockFactory() {
         return namedLockFactory;
     }
 
     public String toString() {
         return getClass().getSimpleName()
                 + "(nameMapper=" + nameMapper
                 + ", namedLockFactory=" + namedLockFactory
                 + ")";
     }
 
     private static class AdaptedLockSyncContext implements SyncContext {
         private static final Logger LOGGER = LoggerFactory.getLogger(AdaptedLockSyncContext.class);
 
         private final RepositorySystemSession session;
 
         private final boolean shared;
 
         private final NameMapper lockNaming;
 
         private final NamedLockFactory namedLockFactory;
 
         private final long time;
 
         private final TimeUnit timeUnit;
 
         private final int retry;
 
         private final long retryWait;
 
         private final Deque<NamedLock> locks;
 
         private AdaptedLockSyncContext(
                 final RepositorySystemSession session,
                 final boolean shared,
                 final NameMapper lockNaming,
                 final NamedLockFactory namedLockFactory) {
             this.session = session;
             this.shared = shared;
             this.lockNaming = lockNaming;
             this.namedLockFactory = namedLockFactory;
             this.time = getTime(session, DEFAULT_TIME, CONFIG_PROP_TIME);
             this.timeUnit = getTimeUnit(session);
             this.retry = getRetry(session);
             this.retryWait = getRetryWait(session);
             this.locks = new ArrayDeque<>();
 
             if (time < 0L) {
                 throw new IllegalArgumentException(CONFIG_PROP_TIME + " value cannot be negative");
             }
             if (retry < 0L) {
                 throw new IllegalArgumentException(CONFIG_PROP_RETRY + " value cannot be negative");
             }
             if (retryWait < 0L) {
                 throw new IllegalArgumentException(CONFIG_PROP_RETRY_WAIT + " value cannot be negative");
             }
         }
 
         private long getTime(final RepositorySystemSession session, long defaultValue, String... keys) {
             return ConfigUtils.getLong(session, defaultValue, keys);
         }
 
         private TimeUnit getTimeUnit(final RepositorySystemSession session) {
             return TimeUnit.valueOf(ConfigUtils.getString(session, DEFAULT_TIME_UNIT, CONFIG_PROP_TIME_UNIT));
         }
 
         private int getRetry(final RepositorySystemSession session) {
             return ConfigUtils.getInteger(session, DEFAULT_RETRY, CONFIG_PROP_RETRY);
         }
 
         private long getRetryWait(final RepositorySystemSession session) {
             return ConfigUtils.getLong(session, DEFAULT_RETRY_WAIT, CONFIG_PROP_RETRY_WAIT);
         }
 
         @Override
         public void acquire(Collection<? extends Artifact> artifacts, Collection<? extends Metadata> metadatas) {
             Collection<NamedLockKey> keys = lockNaming.nameLocks(session, artifacts, metadatas);
             if (keys.isEmpty()) {
                 return;
             }
 
             final String timeStr = time + " " + timeUnit;
             final String lockKind = shared ? "shared" : "exclusive";
             final NamedLock namedLock = namedLockFactory.getLock(keys);
             if (LOGGER.isTraceEnabled()) {
                 LOGGER.trace(
                         "Need {} lock for {} from {}",
                         lockKind,
                         namedLock.key().resources(),
                         namedLock.key().name());
             }
 
             final int attempts = retry + 1;
             for (int attempt = 1; attempt <= attempts; attempt++) {
                 if (LOGGER.isTraceEnabled()) {
                     LOGGER.trace(
                             "Attempt {}: Acquire {} lock from {}",
                             attempt,
                             lockKind,
                             namedLock.key().name());
                 }
                 try {
                     if (attempt > 1) {
                         Thread.sleep(retryWait);
                     }
                     boolean locked;
                     if (shared) {
                         locked = namedLock.lockShared(time, timeUnit);
                     } else {
                         locked = namedLock.lockExclusively(time, timeUnit);
                     }
 
                     if (locked) {
                         // we are done, get out
                         locks.push(namedLock);
                         return;
                     }
 
                     // we failed; retry
                     if (LOGGER.isTraceEnabled()) {
                         LOGGER.trace(
                                 "Failed to acquire {} lock for '{}' in {}",
                                 lockKind,
                                 namedLock.key().name(),
                                 timeStr);
                     }
                 } catch (InterruptedException e) {
                     // if we are here, means we were interrupted: fail
                     close();
                     Thread.currentThread().interrupt();
                     throw new RuntimeException(e);
                 }
             }
             // if we are here, means all attempts were unsuccessful: fail
             close();
             String message = "Could not acquire " + lockKind + " lock for "
                     + lockSubjects(artifacts, metadatas) + " in " + timeStr
                     + "; consider using '" + CONFIG_PROP_TIME
                     + "' property to increase lock timeout to a value that fits your environment";
             FailedToAcquireLockException ex = new FailedToAcquireLockException(shared, message);
             throw namedLockFactory.onFailure(ex);
         }
 
         private String lockSubjects(
                 Collection<? extends Artifact> artifacts, Collection<? extends Metadata> metadatas) {
             StringBuilder builder = new StringBuilder();
             if (artifacts != null && !artifacts.isEmpty()) {
                 builder.append("artifacts: ")
                         .append(artifacts.stream().map(ArtifactIdUtils::toId).collect(Collectors.joining(", ")));
             }
             if (metadatas != null && !metadatas.isEmpty()) {
                 if (builder.length() != 0) {
                     builder.append("; ");
                 }
                 builder.append("metadata: ")
                         .append(metadatas.stream().map(this::metadataSubjects).collect(Collectors.joining(", ")));
             }
             return builder.toString();
         }
 
         private String metadataSubjects(Metadata metadata) {
             String name = "";
             if (!metadata.getGroupId().isEmpty()) {
                 name += metadata.getGroupId();
                 if (!metadata.getArtifactId().isEmpty()) {
                     name += ":" + metadata.getArtifactId();
                     if (!metadata.getVersion().isEmpty()) {
                         name += ":" + metadata.getVersion();
                     }
                 }
             }
             if (!metadata.getType().isEmpty()) {
                 name += (name.isEmpty() ? "" : ":") + metadata.getType();
             }
             return name;
         }
 
         @Override
         public void close() {
             while (!locks.isEmpty()) {
                 try (NamedLock namedLock = locks.pop()) {
                     namedLock.unlock();
                     if (LOGGER.isTraceEnabled()) {
                         LOGGER.trace(
                                 "Unlocked and closed {} lock of {}", shared ? "shared" : "exclusive", namedLock.key());
                     }
                 }
             }
         }
     }
 }