/*
    * Copyright 2023 LINE Corporation
    *
    * LINE Corporation 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:
    *
    *   https://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.linecorp.centraldogma.server.internal.storage.repository;
  
  import static com.google.common.base.MoreObjects.firstNonNull;
  import static java.util.Objects.requireNonNull;
  
  import java.net.URI;
  import java.util.List;
  import java.util.Optional;
  import java.util.ServiceLoader;
  
  import javax.annotation.Nullable;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.cronutils.model.Cron;
  import com.cronutils.model.CronType;
  import com.cronutils.model.definition.CronDefinitionBuilder;
  import com.cronutils.parser.CronParser;
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
  import com.fasterxml.jackson.annotation.JsonInclude;
  import com.fasterxml.jackson.annotation.JsonInclude.Include;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.google.common.base.MoreObjects;
  import com.google.common.collect.ImmutableList;
  import com.google.common.collect.Streams;
  
  import com.linecorp.centraldogma.server.mirror.Mirror;
  import com.linecorp.centraldogma.server.mirror.MirrorContext;
  import com.linecorp.centraldogma.server.mirror.MirrorCredential;
  import com.linecorp.centraldogma.server.mirror.MirrorDirection;
  import com.linecorp.centraldogma.server.mirror.MirrorProvider;
  import com.linecorp.centraldogma.server.storage.project.Project;
  
  // ignoreUnknown = true for backward compatibility since `type` field is removed.
  @JsonIgnoreProperties(ignoreUnknown = true)
  @JsonInclude(Include.NON_NULL)
  public final class MirrorConfig {
  
      private static final Logger logger = LoggerFactory.getLogger(MirrorConfig.class);
  
      private static final String DEFAULT_SCHEDULE = "0 * * * * ?"; // Every minute
  
      private static final CronParser CRON_PARSER = new CronParser(
              CronDefinitionBuilder.instanceDefinitionFor(CronType.QUARTZ));
  
      private static final List<MirrorProvider> MIRROR_PROVIDERS;
  
      static {
          MIRROR_PROVIDERS = ImmutableList.copyOf(ServiceLoader.load(MirrorProvider.class));
          logger.debug("Available {}s: {}", MirrorProvider.class.getSimpleName(), MIRROR_PROVIDERS);
      }
  
      private final boolean enabled;
      private final MirrorDirection direction;
      @Nullable
      private final String localRepo;
      private final String localPath;
      private final URI remoteUri;
      @Nullable
      private final String gitignore;
      @Nullable
      private final String credentialId;
      private final Cron schedule;
  
      @JsonCreator
      public MirrorConfig(@JsonProperty("enabled") @Nullable Boolean enabled,
                          @JsonProperty("schedule") @Nullable String schedule,
                          @JsonProperty(value = "direction", required = true) MirrorDirection direction,
                          @JsonProperty(value = "localRepo", required = true) String localRepo,
                          @JsonProperty("localPath") @Nullable String localPath,
                          @JsonProperty(value = "remoteUri", required = true) URI remoteUri,
                          @JsonProperty("gitignore") @Nullable Object gitignore,
                          @JsonProperty("credentialId") @Nullable String credentialId) {
          this.enabled = firstNonNull(enabled, true);
          this.schedule = CRON_PARSER.parse(firstNonNull(schedule, DEFAULT_SCHEDULE));
          this.direction = requireNonNull(direction, "direction");
          this.localRepo = requireNonNull(localRepo, "localRepo");
          this.localPath = firstNonNull(localPath, "/");
          this.remoteUri = requireNonNull(remoteUri, "remoteUri");
          if (gitignore != null) {
             if (gitignore instanceof Iterable &&
                 Streams.stream((Iterable<?>) gitignore).allMatch(String.class::isInstance)) {
                 this.gitignore = String.join("\n", (Iterable<String>) gitignore);
             } else if (gitignore instanceof String) {
                 this.gitignore = (String) gitignore;
             } else {
                 throw new IllegalArgumentException(
                         "gitignore: " + gitignore + " (expected: either a string or an array of strings)");
             }
         } else {
             this.gitignore = null;
         }
         this.credentialId = credentialId;
     }
 
     @Nullable
     Mirror toMirror(Project parent, Iterable<MirrorCredential> credentials) {
         if (!enabled || localRepo == null || !parent.repos().exists(localRepo)) {
             return null;
         }
 
         final MirrorContext mirrorContext = new MirrorContext(
                 schedule, direction, findCredential(credentials, remoteUri, credentialId),
                 parent.repos().get(localRepo), localPath, remoteUri, gitignore);
         for (MirrorProvider mirrorProvider : MIRROR_PROVIDERS) {
             final Mirror mirror = mirrorProvider.newMirror(mirrorContext);
             if (mirror != null) {
                 return mirror;
             }
         }
 
         throw new IllegalArgumentException("could not find a mirror provider for " + mirrorContext);
     }
 
     private static MirrorCredential findCredential(Iterable<MirrorCredential> credentials, URI remoteUri,
                                                    @Nullable String credentialId) {
         if (credentialId != null) {
             // Find by credential ID.
             for (MirrorCredential c : credentials) {
                 final Optional<String> id = c.id();
                 if (id.isPresent() && credentialId.equals(id.get())) {
                     return c;
                 }
             }
         } else {
             // Find by host name.
             for (MirrorCredential c : credentials) {
                 if (c.matches(remoteUri)) {
                     return c;
                 }
             }
         }
 
         return MirrorCredential.FALLBACK;
     }
 
     @JsonProperty("enabled")
     public boolean enabled() {
         return enabled;
     }
 
     @JsonProperty("direction")
     public MirrorDirection direction() {
         return direction;
     }
 
     @Nullable
     @JsonProperty("localRepo")
     public String localRepo() {
         return localRepo;
     }
 
     @JsonProperty("localPath")
     public String localPath() {
         return localPath;
     }
 
     @JsonProperty("remoteUri")
     public String remoteUri() {
         return remoteUri.toString();
     }
 
     @JsonProperty("gitignore")
     @Nullable
     public String gitignore() {
         return gitignore;
     }
 
     @Nullable
     @JsonProperty("credentialId")
     public String credentialId() {
         return credentialId;
     }
 
     @JsonProperty("schedule")
     public String schedule() {
         return schedule.asString();
     }
 
     @Override
     public String toString() {
         return MoreObjects.toStringHelper(this).omitNullValues()
                           .add("enabled", enabled)
                           .add("direction", direction)
                           .add("localRepo", localRepo)
                           .add("localPath", localPath)
                           .add("remoteUri", remoteUri)
                           .add("gitignore", gitignore)
                           .add("credentialId", credentialId)
                           .add("schedule", schedule)
                           .toString();
     }
 }