/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2015 wcm.io
    * %%
    * Licensed 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.
   * #L%
   */
  package io.wcm.dam.assetservice.impl;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.commons.lang3.CharEncoding;
  import org.apache.sling.api.SlingHttpServletRequest;
  import org.apache.sling.api.SlingHttpServletResponse;
  import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
  import org.apache.sling.commons.json.JSONArray;
  import org.apache.sling.commons.json.JSONException;
  import org.apache.sling.commons.json.JSONObject;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import io.wcm.handler.media.Media;
  import io.wcm.handler.media.MediaHandler;
  import io.wcm.handler.media.Rendition;
  import io.wcm.wcm.commons.contenttype.ContentType;
  
  /**
   * Implements a simple REST interface that allows resolving DAM asset paths to URLs.
   * For image assets resolving to specific dimensions is supported.
   */
  @SuppressWarnings("deprecation")
  class AssetRequestServlet extends SlingSafeMethodsServlet {
    private static final long serialVersionUID = 1L;
  
    private final DamPathHandler damPathHandler;
  
    private static final Logger log = LoggerFactory.getLogger(AssetRequestServlet.class);
  
    AssetRequestServlet(DamPathHandler damPathHandler) {
      this.damPathHandler = damPathHandler;
    }
  
    @SuppressWarnings("null")
    @Override
    protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException, IOException {
      String assetPath = request.getResource().getPath();
  
      // check if asset path is valid
      if (!damPathHandler.isAllowedAssetPath(assetPath)) {
        log.debug("Asset path not allowed {}", assetPath);
        response.sendError(HttpServletResponse.SC_NOT_FOUND);
        return;
      }
  
      // get media handler
      MediaHandler mediaHandler = request.getResource().adaptTo(MediaHandler.class);
      if (mediaHandler == null) {
        log.debug("Unable to get media handler for {}", assetPath);
        response.sendError(HttpServletResponse.SC_NOT_FOUND);
        return;
      }
  
      // build list of asset service requests with optional input parameters
      List<AssetRequest> requests = AssetRequestParser.getAssetRequests(assetPath, request);
  
      // resolve asset service requests
      List<Media> mediaList = resolveMedia(requests, mediaHandler);
      if (mediaList.isEmpty()) {
        log.debug("No matching assets/renditions found for {}; requests: {}", assetPath, requests);
        response.sendError(HttpServletResponse.SC_NOT_FOUND);
        return;
      }
  
      // output result json
      try {
        JSONArray resultJson = toResultJson(mediaList);
        response.setContentType(ContentType.JSON);
        response.setCharacterEncoding(CharEncoding.UTF_8);
        response.getWriter().write(resultJson.toString());
      }
      catch (JSONException ex) {
        throw new ServletException("Unable to generate JSON.", ex);
     }
   }
 
   private List<Media> resolveMedia(List<AssetRequest> requests, MediaHandler mediaHandler) {
     List<Media> result = new ArrayList<>();
     for (AssetRequest request : requests) {
       Media media = request.resolve(mediaHandler);
       if (media.isValid()) {
         result.add(media);
       }
     }
     return result;
   }
 
   private JSONArray toResultJson(List<Media> mediaList) throws JSONException {
     JSONArray array = new JSONArray();
     for (Media media : mediaList) {
       Rendition rendition = media.getRendition();
       JSONObject mediaObject = new JSONObject();
       mediaObject.put("assetPath", media.getAsset().getPath());
       mediaObject.put("url", media.getUrl());
       if (rendition.getWidth() > 0 && rendition.getHeight() > 0) {
         mediaObject.put("width", rendition.getWidth());
         mediaObject.put("height", rendition.getHeight());
       }
       if (rendition.getFileSize() > 0) {
         mediaObject.put("fileSize", rendition.getFileSize());
       }
       mediaObject.putOpt("fileExtension", rendition.getFileExtension());
       mediaObject.putOpt("mimeType", rendition.getMimeType());
       array.put(mediaObject);
     }
     return array;
   }
 
 }