/*
    * 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.api;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.collect.ImmutableList.toImmutableList;
  import static com.linecorp.centraldogma.server.internal.mirror.DefaultMirroringServicePlugin.mirrorConfig;
  import static com.linecorp.centraldogma.server.internal.storage.repository.DefaultMetaRepository.mirrorFile;
  import static com.linecorp.centraldogma.server.mirror.MirrorUtil.validateMirrorId;
  
  import java.net.URI;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.TimeUnit;
  
  import javax.annotation.Nullable;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.cronutils.model.Cron;
  import com.google.common.collect.ImmutableList;
  import com.google.common.collect.ImmutableMap;
  
  import com.linecorp.armeria.server.annotation.ConsumesJson;
  import com.linecorp.armeria.server.annotation.Delete;
  import com.linecorp.armeria.server.annotation.Get;
  import com.linecorp.armeria.server.annotation.Param;
  import com.linecorp.armeria.server.annotation.Post;
  import com.linecorp.armeria.server.annotation.ProducesJson;
  import com.linecorp.armeria.server.annotation.Put;
  import com.linecorp.armeria.server.annotation.StatusCode;
  import com.linecorp.armeria.server.annotation.decorator.RequestTimeout;
  import com.linecorp.centraldogma.common.Author;
  import com.linecorp.centraldogma.common.Change;
  import com.linecorp.centraldogma.common.Markup;
  import com.linecorp.centraldogma.common.ProjectRole;
  import com.linecorp.centraldogma.common.RepositoryRole;
  import com.linecorp.centraldogma.common.Revision;
  import com.linecorp.centraldogma.internal.api.v1.MirrorDto;
  import com.linecorp.centraldogma.internal.api.v1.MirrorRequest;
  import com.linecorp.centraldogma.internal.api.v1.PushResultDto;
  import com.linecorp.centraldogma.server.CentralDogmaConfig;
  import com.linecorp.centraldogma.server.ZoneConfig;
  import com.linecorp.centraldogma.server.command.Command;
  import com.linecorp.centraldogma.server.command.CommandExecutor;
  import com.linecorp.centraldogma.server.internal.api.auth.RequiresProjectRole;
  import com.linecorp.centraldogma.server.internal.api.auth.RequiresRepositoryRole;
  import com.linecorp.centraldogma.server.internal.mirror.MirrorRunner;
  import com.linecorp.centraldogma.server.internal.mirror.MirrorSchedulingService;
  import com.linecorp.centraldogma.server.internal.storage.project.ProjectApiManager;
  import com.linecorp.centraldogma.server.metadata.User;
  import com.linecorp.centraldogma.server.mirror.Mirror;
  import com.linecorp.centraldogma.server.mirror.MirrorAccessController;
  import com.linecorp.centraldogma.server.mirror.MirrorListener;
  import com.linecorp.centraldogma.server.mirror.MirrorResult;
  import com.linecorp.centraldogma.server.mirror.MirroringServicePluginConfig;
  import com.linecorp.centraldogma.server.storage.repository.MetaRepository;
  import com.linecorp.centraldogma.server.storage.repository.Repository;
  
  /**
   * Annotated service object for managing mirroring service.
   */
  @ProducesJson
  public class MirroringServiceV1 extends AbstractService {
  
      private static final Logger logger = LoggerFactory.getLogger(MirroringServiceV1.class);
  
      // TODO(ikhoon):
      //  - Write documentation for the REST API specification
      //  - Add Java APIs to the CentralDogma client
  
      private final ProjectApiManager projectApiManager;
      private final MirrorRunner mirrorRunner;
      private final Map<String, Object> mirrorZoneConfig;
      @Nullable
      private final ZoneConfig zoneConfig;
      private final MirrorAccessController accessController;
  
      public MirroringServiceV1(ProjectApiManager projectApiManager, CommandExecutor executor,
                                MirrorRunner mirrorRunner, CentralDogmaConfig config,
                                MirrorAccessController accessController) {
          super(executor);
          this.projectApiManager = projectApiManager;
         this.mirrorRunner = mirrorRunner;
         zoneConfig = config.zone();
         mirrorZoneConfig = mirrorZoneConfig(config);
         this.accessController = accessController;
     }
 
     private static Map<String, Object> mirrorZoneConfig(CentralDogmaConfig config) {
         final MirroringServicePluginConfig mirrorConfig = mirrorConfig(config);
         final ImmutableMap.Builder<String, Object> builder = ImmutableMap.builderWithExpectedSize(2);
         final boolean zonePinned = mirrorConfig != null && mirrorConfig.zonePinned();
         builder.put("zonePinned", zonePinned);
         final ZoneConfig zone = config.zone();
         if (zone != null) {
             builder.put("zone", zone);
         }
         return builder.build();
     }
 
     /**
      * GET /projects/{projectName}/mirrors
      *
      * <p>Returns the list of the mirrors in the project.
      */
     @RequiresProjectRole(ProjectRole.OWNER)
     @Get("/projects/{projectName}/mirrors")
     public CompletableFuture<List<MirrorDto>> listProjectMirrors(@Param String projectName) {
         final CompletableFuture<List<Mirror>> future = metaRepo(projectName).mirrors(true);
         return convertToMirrorDtos(projectName, future);
     }
 
     /**
      * GET /projects/{projectName}/repos/{repoName}/mirrors
      *
      * <p>Returns the list of the mirrors in the repository.
      */
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     @Get("/projects/{projectName}/repos/{repoName}/mirrors")
     public CompletableFuture<List<MirrorDto>> listRepoMirrors(@Param String projectName,
                                                               Repository repository) {
         final CompletableFuture<List<Mirror>> future = metaRepo(projectName).mirrors(repository.name(), true);
         return convertToMirrorDtos(projectName, future);
     }
 
     /**
      * GET /projects/{projectName}/repos/{repoName}/mirrors/{id}
      *
      * <p>Returns the mirror of the ID in the project mirror list.
      */
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     @Get("/projects/{projectName}/repos/{repoName}/mirrors/{id}")
     public CompletableFuture<MirrorDto> getMirror(@Param String projectName,
                                                   Repository repository,
                                                   @Param String id) {
         return metaRepo(projectName).mirror(repository.name(), id).thenCompose(mirror -> {
             return accessController.isAllowed(mirror.remoteRepoUri()).thenApply(allowed -> {
                 return convertToMirrorDto(projectName, mirror, allowed);
             });
         });
     }
 
     /**
      * POST /projects/{projectName}/repos/{repoName}/mirrors
      *
      * <p>Creates a new mirror.
      */
     @Post("/projects/{projectName}/repos/{repoName}/mirrors")
     @ConsumesJson
     @StatusCode(201)
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     public CompletableFuture<PushResultDto> createMirror(@Param String projectName,
                                                          Repository repository,
                                                          MirrorRequest newMirror,
                                                          Author author, User user) {
         validateMirrorId(newMirror.id());
         return createOrUpdate(projectName, repository.name(), newMirror, author, user, false);
     }
 
     /**
      * PUT /projects/{projectName}/repos/{repoName}/mirrors
      *
      * <p>Update the exising mirror.
      */
     @ConsumesJson
     @Put("/projects/{projectName}/repos/{repoName}/mirrors/{id}")
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     public CompletableFuture<PushResultDto> updateMirror(@Param String projectName,
                                                          Repository repository,
                                                          MirrorRequest mirror,
                                                          @Param String id, Author author, User user) {
         checkArgument(id.equals(mirror.id()), "The mirror ID (%s) can't be updated", id);
         return createOrUpdate(projectName, repository.name(), mirror, author, user, true);
     }
 
     /**
      * DELETE /projects/{projectName}/repos/{repoName}/mirrors/{id}
      *
      * <p>Delete the existing mirror.
      */
     @Delete("/projects/{projectName}/repos/{repoName}/mirrors/{id}")
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     public CompletableFuture<Void> deleteMirror(@Param String projectName,
                                                 Repository repository,
                                                 @Param String id, Author author) {
         final MetaRepository metaRepository = metaRepo(projectName);
         final String repoName = repository.name();
         return metaRepository.mirror(repoName, id).thenCompose(mirror -> {
             // mirror exists.
             final Command<Revision> command =
                     Command.push(author, projectName, metaRepository.name(),
                                  Revision.HEAD, "Delete mirror: " + id + " in " + repoName, "",
                                  Markup.PLAINTEXT, Change.ofRemoval(mirrorFile(repoName, id)));
             return executor().execute(command).thenApply(result -> null);
         });
     }
 
     private CompletableFuture<PushResultDto> createOrUpdate(
             String projectName, String repoName, MirrorRequest newMirror,
             Author author, User user, boolean update) {
         final MetaRepository metaRepo = metaRepo(projectName);
 
         return metaRepo.createMirrorPushCommand(repoName, newMirror, author, zoneConfig, update).thenCompose(
                 command -> {
                     return executor().execute(command).thenApply(revision -> {
                         metaRepo.mirror(repoName, newMirror.id(), revision)
                                 .handle((mirror, cause) -> {
                                     if (cause != null) {
                                         // This should not happen in normal cases.
                                         logger.warn("Failed to get the mirror: {}", newMirror.id(), cause);
                                         return null;
                                     }
                                     return notifyMirrorEvent(mirror, user, update);
                                 });
                         return new PushResultDto(revision, command.timestamp());
                     });
                 });
     }
 
     private Void notifyMirrorEvent(Mirror mirror, User user, boolean update) {
         try {
             final MirrorListener listener = MirrorSchedulingService.mirrorListener();
             if (update) {
                 listener.onUpdate(mirror, user, accessController);
             } else {
                 listener.onCreate(mirror, user, accessController);
             }
         } catch (Throwable ex) {
             logger.warn("Failed to notify the mirror listener. (mirror: {})", mirror, ex);
         }
         return null;
     }
 
     /**
      * POST /projects/{projectName}/repos/{repoName}/mirrors/{mirrorId}/run
      *
      * <p>Runs the mirroring task immediately.
      */
     // Mirroring may be a long-running task, so we need to increase the timeout.
     @RequestTimeout(value = 5, unit = TimeUnit.MINUTES)
     @Post("/projects/{projectName}/repos/{repoName}/mirrors/{mirrorId}/run")
     @RequiresRepositoryRole(RepositoryRole.ADMIN)
     public CompletableFuture<MirrorResult> runMirror(@Param String projectName,
                                                      Repository repository,
                                                      @Param String mirrorId,
                                                      User user) throws Exception {
         return mirrorRunner.run(projectName, repository.name(), mirrorId, user);
     }
 
     /**
      * GET /mirror/config
      *
      * <p>Returns the configuration of the mirroring service.
      */
     @Get("/mirror/config")
     public Map<String, Object> config() {
         // TODO(ikhoon): Add more configurations if necessary.
         return mirrorZoneConfig;
     }
 
     private CompletableFuture<List<MirrorDto>> convertToMirrorDtos(
             String projectName, CompletableFuture<List<Mirror>> future) {
         return future.thenCompose(mirrors -> {
             final ImmutableList<String> remoteUris = mirrors.stream().map(
                     mirror -> mirror.remoteRepoUri().toString()).collect(
                     toImmutableList());
             return accessController.isAllowed(remoteUris).thenApply(acl -> {
                 return mirrors.stream()
                               .map(mirror -> convertToMirrorDto(projectName, mirror, acl))
                               .collect(toImmutableList());
             });
         });
     }
 
     private static MirrorDto convertToMirrorDto(String projectName, Mirror mirror, Map<String, Boolean> acl) {
         final boolean allowed = acl.get(mirror.remoteRepoUri().toString());
         return convertToMirrorDto(projectName, mirror, allowed);
     }
 
     private static MirrorDto convertToMirrorDto(String projectName, Mirror mirror, boolean allowed) {
         final URI remoteRepoUri = mirror.remoteRepoUri();
         final Cron schedule = mirror.schedule();
         final String scheduleStr = schedule != null ? schedule.asString() : null;
         return new MirrorDto(mirror.id(),
                              mirror.enabled(), projectName,
                              scheduleStr,
                              mirror.direction().name(),
                              mirror.localRepo().name(),
                              mirror.localPath(),
                              remoteRepoUri.getScheme(),
                              remoteRepoUri.getAuthority() + remoteRepoUri.getPath(),
                              mirror.remotePath(),
                              mirror.remoteBranch(),
                              mirror.gitignore(),
                              mirror.credential().name(), mirror.zone(), allowed);
     }
 
     private MetaRepository metaRepo(String projectName) {
         return projectApiManager.getProject(projectName).metaRepo();
     }
 }