/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.assetmanager.impl.endpoint;
  
  import static javax.servlet.http.HttpServletResponse.SC_BAD_REQUEST;
  import static javax.servlet.http.HttpServletResponse.SC_CREATED;
  import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
  import static javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
  import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
  import static javax.servlet.http.HttpServletResponse.SC_NOT_MODIFIED;
  import static javax.servlet.http.HttpServletResponse.SC_NO_CONTENT;
  import static javax.servlet.http.HttpServletResponse.SC_OK;
  import static org.opencastproject.assetmanager.api.AssetManager.DEFAULT_OWNER;
  import static org.opencastproject.systems.OpencastConstants.WORKFLOW_PROPERTIES_NAMESPACE;
  import static org.opencastproject.util.RestUtil.R.badRequest;
  import static org.opencastproject.util.RestUtil.R.forbidden;
  import static org.opencastproject.util.RestUtil.R.noContent;
  import static org.opencastproject.util.RestUtil.R.notFound;
  import static org.opencastproject.util.RestUtil.R.ok;
  import static org.opencastproject.util.doc.rest.RestParameter.Type.STRING;
  
  import org.opencastproject.assetmanager.api.AssetManager;
  import org.opencastproject.assetmanager.api.Property;
  import org.opencastproject.assetmanager.api.PropertyId;
  import org.opencastproject.assetmanager.api.Value;
  import org.opencastproject.mediapackage.MediaPackage;
  import org.opencastproject.mediapackage.MediaPackageImpl;
  import org.opencastproject.rest.AbstractJobProducerEndpoint;
  import org.opencastproject.security.api.UnauthorizedException;
  import org.opencastproject.util.Checksum;
  import org.opencastproject.util.ChecksumType;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.doc.rest.RestParameter;
  import org.opencastproject.util.doc.rest.RestParameter.Type;
  import org.opencastproject.util.doc.rest.RestQuery;
  import org.opencastproject.util.doc.rest.RestResponse;
  import org.opencastproject.util.doc.rest.RestService;
  
  import com.google.gson.Gson;
  import com.google.gson.reflect.TypeToken;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Optional;
  
  import javax.ws.rs.DELETE;
  import javax.ws.rs.FormParam;
  import javax.ws.rs.GET;
  import javax.ws.rs.HeaderParam;
  import javax.ws.rs.POST;
  import javax.ws.rs.Path;
  import javax.ws.rs.PathParam;
  import javax.ws.rs.Produces;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  
  /**
   * A base REST endpoint for the {@link AssetManager}.
   * <p>
   * The endpoint provides assets over http (see {@link org.opencastproject.assetmanager.impl.HttpAssetProvider}).
   * <p>
   * No @Path annotation here since this class cannot be created by JAX-RS. Put it on the concrete implementations.
   */
  @RestService(name = "assetManager", title = "AssetManager",
      notes = {
          "All paths are relative to the REST endpoint base (something like http://your.server/files)",
          "If you notice that this service is not working as expected, there might be a bug! "
              + "You should file an error report with your server logs from the time when the error occurred: "
              + "<a href=\"http://github.com/opencast/opencast/issues\">Opencast Issue Tracker</a>"
      },
      abstractText = "This service indexes and queries available (distributed) episodes.")
  public abstract class AbstractAssetManagerRestEndpoint extends AbstractJobProducerEndpoint {
    protected static final Logger logger = LoggerFactory.getLogger(AbstractAssetManagerRestEndpoint.class);
  
    private final Gson gson = new Gson();
  
   private final java.lang.reflect.Type stringMapType = new TypeToken<Map<String, String>>() { }.getType();
 
   public abstract AssetManager getAssetManager();
 
   /**
    * @deprecated use {@link #snapshot} instead
    */
   @POST
   @Path("add")
   @RestQuery(
       name = "add",
       description = "Adds a media package to the asset manager. This method is deprecated in "
           + "favor of method POST 'snapshot'.",
       restParameters = {
           @RestParameter(
               name = "mediapackage",
               isRequired = true,
               type = Type.TEXT,
               description = "The media package to add to the search index.")},
       responses = {
           @RestResponse(
               description = "The media package was added, no content to return.",
               responseCode = SC_NO_CONTENT),
           @RestResponse(
               description = "Not allowed to add a media package.",
               responseCode = SC_FORBIDDEN),
           @RestResponse(
               description = "There has been an internal error and the media package could not be added",
               responseCode = SC_INTERNAL_SERVER_ERROR)},
       returnDescription = "No content is returned.")
   @Deprecated
   public Response add(@FormParam("mediapackage") final MediaPackageImpl mediaPackage) {
     return snapshot(mediaPackage);
   }
 
   @POST
   @Path("snapshot")
   @RestQuery(name = "snapshot", description = "Take a versioned snapshot of a media package.",
       restParameters = {
           @RestParameter(
               name = "mediapackage",
               isRequired = true,
               type = Type.TEXT,
               description = "The media package to take a snapshot from.")},
       responses = {
           @RestResponse(
               description = "A snapshot of the media package has been taken, no content to return.",
               responseCode = SC_NO_CONTENT),
           @RestResponse(
               description = "Not allowed to take a snapshot.",
               responseCode = SC_FORBIDDEN),
           @RestResponse(
               description = "There has been an internal error and no snapshot could be taken.",
               responseCode = SC_INTERNAL_SERVER_ERROR)},
       returnDescription = "No content is returned.")
   public Response snapshot(@FormParam("mediapackage") final MediaPackageImpl mediaPackage) {
     try {
       getAssetManager().takeSnapshot(DEFAULT_OWNER, mediaPackage);
       return noContent();
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @POST
   @Path("updateIndex")
   @RestQuery(name = "updateIndex",
       description = "Trigger search index update for event. The usage of this is limited to global administrators.",
       restParameters = {
           @RestParameter(
               name = "id",
               isRequired = true,
               type = STRING,
               description = "The event ID to trigger an index update for.")},
       responses = {
           @RestResponse(
               description = "Update successfully triggered.",
               responseCode = SC_NO_CONTENT),
           @RestResponse(
               description = "Not allowed to trigger update.",
               responseCode = SC_FORBIDDEN),
           @RestResponse(
               description = "No such event found.",
               responseCode = SC_NOT_FOUND)},
       returnDescription = "No content is returned.")
   public Response indexUpdate(@FormParam("id") final String id) {
     try {
       getAssetManager().triggerIndexUpdate(id);
       return noContent();
     } catch (UnauthorizedException e) {
       return forbidden();
     } catch (NotFoundException e) {
       return notFound();
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @DELETE
   @Path("delete/{id}")
   @RestQuery(name = "deleteSnapshots",
       description = "Removes snapshots of an episode, owned by the default owner from the asset manager.",
       pathParameters = {
           @RestParameter(
               name = "id",
               isRequired = true,
               type = Type.STRING,
               description = "The media package ID of the episode whose snapshots shall be removed"
                   + " from the asset manager.")},
       responses = {
           @RestResponse(
               description = "Snapshots have been removed, no content to return.",
               responseCode = SC_NO_CONTENT),
           @RestResponse(
               description = "The episode does either not exist or no snapshots are owned by the default owner.",
               responseCode = SC_NOT_FOUND),
           @RestResponse(
               description = "Not allowed to delete this episode.",
               responseCode = SC_FORBIDDEN),
           @RestResponse(
               description = "There has been an internal error and the episode could not be deleted.",
               responseCode = SC_INTERNAL_SERVER_ERROR)},
       returnDescription = "No content is returned.")
   public Response delete(@PathParam("id") final String mediaPackageId) {
     if (StringUtils.isEmpty(mediaPackageId)) {
       return notFound();
     }
     try {
       if (getAssetManager().deleteSnapshots(mediaPackageId) > 0) {
         return noContent();
       }
       return notFound();
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @GET
   @Produces(MediaType.TEXT_XML)
   @Path("episode/{mediaPackageID}")
   @RestQuery(name = "getLatestEpisode",
       description = "Get the media package from the last snapshot of an episode.",
       returnDescription = "The media package",
       pathParameters = {
           @RestParameter(
               name = "mediaPackageID",
               description = "the media package ID",
               isRequired = true,
               type = STRING)
       },
       responses = {
           @RestResponse(responseCode = SC_OK, description = "Media package returned"),
           @RestResponse(responseCode = SC_NOT_FOUND, description = "Not found"),
           @RestResponse(responseCode = SC_FORBIDDEN, description = "Not allowed to read media package."),
           @RestResponse(responseCode = SC_INTERNAL_SERVER_ERROR, description = "There has been an internal error.")
       })
   public Response getMediaPackage(@PathParam("mediaPackageID") final String mediaPackageId) {
 
     try {
       Optional<MediaPackage> mp = getAssetManager().getMediaPackage(mediaPackageId);
 
       if (mp.isPresent()) {
         return ok(mp.get());
       } else {
         return notFound();
       }
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @GET
   @Path("assets/{mediaPackageID}/{mediaPackageElementID}/{version}/{filename}")
   @RestQuery(name = "getAsset",
       description = "Get an asset",
       returnDescription = "The file",
       pathParameters = {
           @RestParameter(
               name = "mediaPackageID",
               description = "the media package identifier",
               isRequired = true,
               type = STRING),
           @RestParameter(
               name = "mediaPackageElementID",
               description = "the media package element identifier",
               isRequired = true,
               type = STRING),
           @RestParameter(
               name = "version",
               description = "the media package version",
               isRequired = true,
               type = STRING),
           @RestParameter(
               name = "filename",
               description = "a descriptive filename used as the download filename",
               isRequired = false,
               type = STRING)},
       responses = {
           @RestResponse(
               responseCode = SC_OK,
               description = "File returned"),
           @RestResponse(
               responseCode = SC_NOT_FOUND,
               description = "Not found"),
           @RestResponse(
               responseCode = SC_NOT_MODIFIED,
               description = "If file not modified"),
           @RestResponse(
               description = "Not allowed to read assets of this snapshot.",
               responseCode = SC_FORBIDDEN),
           @RestResponse(
               description = "There has been an internal error.",
               responseCode = SC_INTERNAL_SERVER_ERROR)})
   public Response getAsset(@PathParam("mediaPackageID") final String mediaPackageID,
                            @PathParam("mediaPackageElementID") final String mediaPackageElementID,
                            @PathParam("version") final String version,
                            @PathParam("filename") String fileName,
                            @HeaderParam("If-None-Match") String ifNoneMatch) {
 
     try {
       final var v = getAssetManager().toVersion(version);
       if (v.isPresent()) {
         var assetOpt = getAssetManager().getAsset(v.get(), mediaPackageID, mediaPackageElementID);
         if (assetOpt.isPresent()) {
           var asset = assetOpt.get();
 
           if (StringUtils.isNotBlank(ifNoneMatch)) {
             Checksum checksum = asset.getChecksum();
 
             if (checksum != null && checksum.getType().equals(ChecksumType.DEFAULT_TYPE)) {
               String md5 = checksum.getValue();
 
               if (md5.equals(ifNoneMatch)) {
                 return Response.notModified(md5).build();
               }
             }
             else {
               logger.warn("Checksum of asset {} of media package {} is of incorrect type or missing",
                       mediaPackageElementID, mediaPackageID);
             }
           }
 
           if (StringUtils.isBlank(fileName)) {
             String suffix = "unknown";
             if (asset.getMimeType().isPresent()) {
               var mimetype = asset.getMimeType().get();
               if (mimetype.getSuffix().isPresent()) {
                 suffix = mimetype.getSuffix().get();
               }
             }
             fileName = mediaPackageElementID
                 .concat(".")
                 .concat(suffix);
           }
 
           // Write the file contents back
           Optional<Long> length = asset.getSize() > 0 ? Optional.of(asset.getSize()) : Optional.empty();
           return ok(asset.getInputStream(),
                   asset.getMimeType().isPresent()
                       ? Optional.of(asset.getMimeType().get().toString())
                       : Optional.empty(),
                   length,
                   Optional.of(fileName));
         }
         // none
         return notFound();
       }
       // cannot parse version
       return badRequest("malformed version");
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @GET
   @Produces(MediaType.APPLICATION_JSON)
   @Path("{mediaPackageID}/properties.json")
   @RestQuery(name = "getProperties",
       description = "Get stored properties for an episode.",
       returnDescription = "Properties as JSON",
       pathParameters = {
           @RestParameter(
               name = "mediaPackageID",
               description = "the media package ID",
               isRequired = true,
               type = STRING)
       }, restParameters = {
           @RestParameter(
               name = "namespace",
               description = "property namespace",
               isRequired = false,
               type = STRING)
       },
       responses = {
           @RestResponse(responseCode = SC_OK, description = "Media package returned"),
           @RestResponse(responseCode = SC_NOT_FOUND, description = "Not found"),
           @RestResponse(responseCode = SC_FORBIDDEN, description = "Not allowed to read media package."),
           @RestResponse(responseCode = SC_INTERNAL_SERVER_ERROR, description = "There has been an internal error.")
       })
   public Response getProperties(@PathParam("mediaPackageID") final String mediaPackageId,
           @FormParam("namespace") final String namespace) {
     try {
       getAssetManager().selectProperties(mediaPackageId, namespace);
 
       // build map from properties
       HashMap<String, HashMap<String, String>> properties = new HashMap<>();
       for (final Property property : getAssetManager().selectProperties(mediaPackageId, namespace)) {
         final String key = property.getId().getNamespace() + "." + property.getId().getName();
         final HashMap<String, String> val = new HashMap<>();
         val.put("type", property.getValue().getType().getClass().getSimpleName());
         val.put("value", property.getValue().get().toString());
         properties.put(key, val);
       }
       return ok(gson.toJson(properties));
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
   @GET
   @Produces(MediaType.APPLICATION_JSON)
   @Path("{mediaPackageID}/workflowProperties.json")
   @RestQuery(name = "getWorkflowProperties",
       description = "Get stored workflow properties for an episode.",
       returnDescription = "Properties as JSON",
       pathParameters = {
           @RestParameter(
               name = "mediaPackageID",
               description = "the media package ID",
               isRequired = true,
               type = STRING)
       },
       responses = {
           @RestResponse(responseCode = SC_OK, description = "Media package returned"),
           @RestResponse(responseCode = SC_OK, description = "Invalid parameters"),
           @RestResponse(responseCode = SC_NOT_FOUND, description = "Not found"),
           @RestResponse(responseCode = SC_FORBIDDEN, description = "Not allowed to read media package."),
           @RestResponse(responseCode = SC_INTERNAL_SERVER_ERROR, description = "There has been an internal error.")
       })
   public Response getWorkflowProperties(@PathParam("mediaPackageID") final String mediaPackageId) {
     try {
       // build map from properties
       HashMap<String, String> properties = new HashMap<>();
       for (final Property property
           : getAssetManager().selectProperties(mediaPackageId, WORKFLOW_PROPERTIES_NAMESPACE)) {
         properties.put(property.getId().getName(), property.getValue().get(Value.STRING));
       }
       return ok(gson.toJson(properties));
     } catch (Exception e) {
       return handleException(e);
     }
   }
 
 
   @POST
   @Path("{mediaPackageID}/workflowProperties")
   @RestQuery(name = "setWorkflowProperties",
       description = "Set additional workflow properties",
       pathParameters = {
           @RestParameter(
               name = "mediaPackageID",
               description = "the media package ID",
               isRequired = true,
               type = STRING)
       },
       restParameters = {
           @RestParameter(
               name = "properties",
               isRequired = true,
               type = STRING,
               description = "JSON object containing new properties")
       },
       responses = {
           @RestResponse(description = "Properties successfully set", responseCode = SC_CREATED),
           @RestResponse(description = "Invalid data", responseCode = SC_BAD_REQUEST),
           @RestResponse(description = "Internal error", responseCode = SC_INTERNAL_SERVER_ERROR) },
       returnDescription = "Returned status code indicates success")
   public Response setWorkflowProperties(@PathParam("mediaPackageID") final String mediaPackageId,
           @FormParam("properties") final String propertiesJSON) {
     Map<String, String> properties;
     try {
       properties = gson.fromJson(propertiesJSON, stringMapType);
     } catch (Exception e) {
       return badRequest();
     }
     for (final Map.Entry<String, String> entry : properties.entrySet()) {
       final PropertyId propertyId = PropertyId.mk(mediaPackageId, WORKFLOW_PROPERTIES_NAMESPACE, entry.getKey());
       final Property property = Property.mk(propertyId, Value.mk(entry.getValue()));
       if (!getAssetManager().setProperty(property)) {
         return notFound();
       }
     }
     return noContent();
   }
 
   /** Unify exception handling. */
   public static Response handleException(Exception e) {
     logger.debug("Error calling REST method", e);
     Throwable cause = e;
     if (e.getCause() != null) {
       cause = e.getCause();
     }
     if (cause instanceof UnauthorizedException) {
       return forbidden();
     }
 
     throw new WebApplicationException(e, Response.Status.INTERNAL_SERVER_ERROR);
   }
 }