/*
    * 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.staticfiles.endpoint;
  
  import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
  import static javax.servlet.http.HttpServletResponse.SC_NO_CONTENT;
  import static org.opencastproject.util.doc.rest.RestParameter.Type.STRING;
  
  import org.opencastproject.security.api.SecurityService;
  import org.opencastproject.staticfiles.api.StaticFileService;
  import org.opencastproject.systems.OpencastConstants;
  import org.opencastproject.util.MimeTypes;
  import org.opencastproject.util.NotFoundException;
  import org.opencastproject.util.OsgiUtil;
  import org.opencastproject.util.ProgressInputStream;
  import org.opencastproject.util.RestUtil;
  import org.opencastproject.util.RestUtil.R;
  import org.opencastproject.util.UrlSupport;
  import org.opencastproject.util.data.Option;
  import org.opencastproject.util.doc.rest.RestParameter;
  import org.opencastproject.util.doc.rest.RestQuery;
  import org.opencastproject.util.doc.rest.RestResponse;
  import org.opencastproject.util.doc.rest.RestService;
  
  import org.apache.commons.fileupload.FileItemIterator;
  import org.apache.commons.fileupload.FileItemStream;
  import org.apache.commons.fileupload.servlet.ServletFileUpload;
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang3.BooleanUtils;
  import org.osgi.service.cm.ConfigurationException;
  import org.osgi.service.component.ComponentContext;
  import org.osgi.service.component.annotations.Component;
  import org.osgi.service.component.annotations.Reference;
  import org.osgi.service.jaxrs.whiteboard.propertytypes.JaxrsResource;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.beans.PropertyChangeEvent;
  import java.beans.PropertyChangeListener;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URI;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.ws.rs.Consumes;
  import javax.ws.rs.DELETE;
  import javax.ws.rs.GET;
  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.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.Status;
  
  /**
   * Stores and serves static files via HTTP.
   */
  @Path("/staticfiles")
  @RestService(
      name = "StaticResourceService",
      title = "Static Resources Service",
      abstractText = "This service allows the uploading of static resources such as videos and images.",
      notes = {
          "All paths above are relative to the REST endpoint base (something like http://your.server/files)",
          "If the service is down or not working it will return a status 503, this means the the "
              + "underlying service is not working and is either restarting or has failed",
          "A status code 500 means a general failure has occurred which is not recoverable and was "
              + "not anticipated. In other words, there is a bug! You should file an error report "
              + "with your server logs from the time when the error occurred: "
              + "<a href=\"https://github.com/opencast/opencast/issues\">Opencast Issue Tracker</a>"
      }
  )
  @Component(
      immediate = true,
      service = StaticFileRestService.class,
      property = {
         "service.description=Static File Service REST Endpoint",
         "opencast.service.type=org.opencastproject.staticfiles",
         "opencast.service.path=/staticfiles",
         "opencast.service.jobproducer=false"
     }
 )
 @JaxrsResource
 public class StaticFileRestService {
 
   /** The logging facility */
   private static final Logger logger = LoggerFactory.getLogger(StaticFileRestService.class);
 
   /** The default URL path of the static files */
   public static final String STATICFILES_URL_PATH = "staticfiles";
 
   /** The key to find whether the static file webserver is enabled or not. */
   public static final String STATICFILES_WEBSERVER_ENABLED_KEY = "org.opencastproject.staticfiles.webserver.enabled";
 
   /** The key to find the URL for where a webserver is hosting the static files. */
   public static final String STATICFILES_WEBSERVER_URL_KEY = "org.opencastproject.staticfiles.webserver.url";
 
   /** The key to find the maximum sized file to accept as an upload. */
   public static final String STATICFILES_UPLOAD_MAX_SIZE_KEY = "org.opencastproject.staticfiles.upload.max.size";
 
   /** The security service */
   private SecurityService securityService = null;
 
   /** The static file service */
   private StaticFileService staticFileService;
 
   /** The URL of the current server */
   private String serverUrl;
 
   /** The URL to serve static files from a webserver instead of Opencast. */
   private Option<String> webserverURL = Option.none();
 
   /** The maximum file size to allow to be uploaded in bytes, default 1GB */
   private long maxUploadSize = 1000000000;
 
   /**
    * Whether to provide urls to download the static files from a webserver
    * without organization and security protection, or use Opencast to provide
    * the files.
    */
   protected boolean useWebserver = false;
 
   /** OSGi callback to bind service instance. */
   @Reference
   public void setStaticFileService(StaticFileService staticFileService) {
     this.staticFileService = staticFileService;
   }
 
   /** OSGi callback to bind service instance. */
   @Reference
   public void setSecurityService(SecurityService securityService) {
     this.securityService = securityService;
   }
 
   /**
    * OSGI callback for activating this component
    *
    * @param cc
    *          the osgi component context
    */
   public void activate(ComponentContext cc) throws ConfigurationException {
     logger.info("Static File REST Service started.");
     serverUrl = OsgiUtil.getContextProperty(cc, OpencastConstants.SERVER_URL_PROPERTY);
     useWebserver = BooleanUtils.toBoolean(OsgiUtil.getOptCfg(cc.getProperties(), STATICFILES_WEBSERVER_ENABLED_KEY)
             .getOrElse("false"));
     webserverURL = OsgiUtil.getOptCfg(cc.getProperties(), STATICFILES_WEBSERVER_URL_KEY);
 
     Option<String> cfgMaxUploadSize = OsgiUtil.getOptContextProperty(cc, STATICFILES_UPLOAD_MAX_SIZE_KEY);
     if (cfgMaxUploadSize.isSome()) {
       maxUploadSize = Long.parseLong(cfgMaxUploadSize.get());
     }
   }
 
   @GET
   @Path("{uuid}")
   @RestQuery(
       name = "getStaticFile",
       description = "Returns a static file resource",
       pathParameters = {
           @RestParameter(
               name = "uuid",
               description = "Static File Universal Unique Id",
               isRequired = true,
               type = RestParameter.Type.STRING
           )
       },
       responses = {
           @RestResponse(
               description = "Returns a static file resource",
               responseCode = HttpServletResponse.SC_OK
           ),
           @RestResponse(
               description = "No file by the given uuid found",
               responseCode = HttpServletResponse.SC_NOT_FOUND
           )
       },
       returnDescription = ""
   )
   public Response getStaticFile(@PathParam("uuid") String uuid) throws NotFoundException {
     try {
       final InputStream file = staticFileService.getFile(uuid);
       final String filename = staticFileService.getFileName(uuid);
       final Long length = staticFileService.getContentLength(uuid);
       // It is safe to pass the InputStream without closing it, JAX-RS takes care of that
       return RestUtil.R.ok(file, getMimeType(filename), Option.some(length), Option.some(filename));
     } catch (NotFoundException | IOException e) {
       return RestUtil.R.notFound();
     }
   }
 
   @POST
   @Consumes(MediaType.MULTIPART_FORM_DATA)
   @Produces(MediaType.TEXT_PLAIN)
   @Path("")
   @RestQuery(
       name = "postStaticFile",
       description = "Post a new static resource",
       bodyParameter = @RestParameter(
           description = "The static resource file",
           isRequired = true,
           name = "BODY",
           type = RestParameter.Type.FILE
       ),
       responses = {
           @RestResponse(
               description = "Returns the id of the uploaded static resource",
               responseCode = HttpServletResponse.SC_CREATED
           ),
           @RestResponse(
               description = "No filename or file to upload found",
               responseCode = HttpServletResponse.SC_BAD_REQUEST
           ),
           @RestResponse(
               description = "The upload size is too big",
               responseCode = HttpServletResponse.SC_BAD_REQUEST
           )
       },
       returnDescription = ""
   )
   public Response postStaticFile(@Context HttpServletRequest request) {
     if (maxUploadSize > 0 && request.getContentLength() > maxUploadSize) {
       logger.warn("Preventing upload of static file as its size {} is larger than the max size allowed {}",
               request.getContentLength(), maxUploadSize);
       return Response.status(Status.BAD_REQUEST).build();
     }
     ProgressInputStream inputStream = null;
     try {
       String filename = null;
       if (ServletFileUpload.isMultipartContent(request)) {
         boolean isDone = false;
         for (FileItemIterator iter = new ServletFileUpload().getItemIterator(request); iter.hasNext();) {
           FileItemStream item = iter.next();
           if (item.isFormField()) {
             continue;
           } else {
             logger.debug("Processing file item");
             filename = item.getName();
             inputStream = new ProgressInputStream(item.openStream());
             inputStream.addPropertyChangeListener(new PropertyChangeListener() {
               @Override
               public void propertyChange(PropertyChangeEvent evt) {
                 long totalNumBytesRead = (Long) evt.getNewValue();
                 if (totalNumBytesRead > maxUploadSize) {
                   logger.warn("Upload limit of {} bytes reached, returning a bad request.", maxUploadSize);
                   throw new WebApplicationException(Status.BAD_REQUEST);
                 }
               }
             });
             isDone = true;
           }
           if (isDone) {
             break;
           }
         }
       } else {
         logger.warn("Request is not multi part request, returning a bad request.");
         return Response.status(Status.BAD_REQUEST).build();
       }
 
       if (filename == null) {
         logger.warn("Request was missing the filename, returning a bad request.");
         return Response.status(Status.BAD_REQUEST).build();
       }
 
       if (inputStream == null) {
         logger.warn("Request was missing the file, returning a bad request.");
         return Response.status(Status.BAD_REQUEST).build();
       }
 
       String uuid = staticFileService.storeFile(filename, inputStream);
       try {
         return Response.created(getStaticFileURL(uuid)).entity(uuid).build();
       } catch (NotFoundException e) {
         logger.error("Previous stored file with uuid {} couldn't beren found:", uuid, e);
         return Response.serverError().build();
       }
     } catch (WebApplicationException e) {
       return e.getResponse();
     } catch (Exception e) {
       logger.error("Unable to store file", e);
       return Response.serverError().build();
     } finally {
       IOUtils.closeQuietly(inputStream);
     }
   }
 
   @POST
   @Path("{uuid}/persist")
   @RestQuery(
       name = "persistFile",
       description = "Persists a recently uploaded file to the permanent storage",
       pathParameters = {
           @RestParameter(description = "File UUID", isRequired = true, name = "uuid", type = RestParameter.Type.STRING)
       },
       responses = {
           @RestResponse(
               description = "The file has been persisted",
               responseCode = HttpServletResponse.SC_OK
           ),
           @RestResponse(
               description = "No file by the given UUID found",
               responseCode = HttpServletResponse.SC_NOT_FOUND
           )
       },
       returnDescription = ""
   )
   public Response persistFile(@PathParam("uuid") String uuid) throws NotFoundException {
     try {
       staticFileService.persistFile(uuid);
       return R.ok();
     } catch (IOException e) {
       logger.error("Unable to persist file '{}':", uuid, e);
       return R.serverError();
     }
   }
 
   @GET
   @Produces(MediaType.TEXT_PLAIN)
   @Path("{uuid}/url")
   @RestQuery(
       name = "getStaticFileUrl",
       description = "Returns a static file resource's URL",
       pathParameters = {
           @RestParameter(
               name = "uuid",
               description = "Static File Universal Unique Id",
               isRequired = true,
               type = RestParameter.Type.STRING
           )
       },
       responses = {
           @RestResponse(
               description = "Returns a static file resource's URL",
               responseCode = HttpServletResponse.SC_OK
           ),
           @RestResponse(
               description = "No file by the given uuid found",
               responseCode = HttpServletResponse.SC_NOT_FOUND
           )
       },
       returnDescription = ""
   )
   public Response getStaticFileUrl(@PathParam("uuid") String uuid) throws NotFoundException {
     try {
       return Response.ok(getStaticFileURL(uuid).toString()).build();
     } catch (NotFoundException e) {
       throw e;
     } catch (Exception e) {
       logger.error("Unable to retrieve static file URL from {}", uuid, e);
       return Response.serverError().build();
     }
   }
 
   @DELETE
   @Path("{uuid}")
   @RestQuery(
       name = "deleteStaticFile",
       description = "Remove the static file",
       returnDescription = "No content",
       pathParameters = {
           @RestParameter(
               name = "uuid",
               description = "Static File Universal Unique Id",
               isRequired = true,
               type = STRING
           )
       },
       responses = {
           @RestResponse(responseCode = SC_NO_CONTENT, description = "File deleted"),
           @RestResponse(responseCode = SC_NOT_FOUND, description = "No file by the given uuid found")
       }
   )
   public Response deleteStaticFile(@PathParam("uuid") String uuid) throws NotFoundException {
     try {
       staticFileService.deleteFile(uuid);
       return Response.noContent().build();
     } catch (NotFoundException e) {
       throw e;
     } catch (Exception e) {
       logger.error("Unable to delete static file {}", uuid, e);
       return Response.serverError().build();
     }
   }
 
   /**
    * Get the URI for a static file resource depending on whether to get it
    * direct from Opencast or from a webserver.
    *
    * @param uuid
    *          The unique identifier for the static file.
    * @return The URL for the static file resource.
    * @throws NotFoundException
    *           if the resource couldn't been found
    */
   public URI getStaticFileURL(String uuid) throws NotFoundException {
     if (useWebserver && webserverURL.isSome()) {
       return URI.create(UrlSupport.concat(webserverURL.get(), securityService.getOrganization().getId(), uuid,
               staticFileService.getFileName(uuid)));
     } else {
       return URI.create(UrlSupport.concat(serverUrl, STATICFILES_URL_PATH, uuid));
     }
   }
 
   private Option<String> getMimeType(final String filename) {
     Option<String> mimeType;
     try {
       mimeType = Option.some(MimeTypes.fromString(filename).toString());
     } catch (Exception e) {
       logger.warn("Unable to detect the mime type of file {}", filename);
       mimeType = Option.<String> none();
     }
     return mimeType;
   }
 
 }