/*
    * Copyright (C) 2023 B3Partners B.V.
    *
    * SPDX-License-Identifier: MIT
    */
   package org.tailormap.api.persistence.helper;
   
   import static org.tailormap.api.persistence.TMFeatureSource.Protocol.WFS;
   import static org.tailormap.api.persistence.json.GeoServiceProtocol.QUANTIZEDMESH;
  import static org.tailormap.api.persistence.json.GeoServiceProtocol.TILES3D;
  import static org.tailormap.api.persistence.json.GeoServiceProtocol.WMS;
  import static org.tailormap.api.persistence.json.GeoServiceProtocol.XYZ;
  
  import java.io.IOException;
  import java.lang.invoke.MethodHandles;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.nio.charset.StandardCharsets;
  import java.time.Instant;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.Set;
  import java.util.function.Predicate;
  import java.util.stream.Collectors;
  import org.apache.commons.lang3.StringUtils;
  import org.geotools.api.data.ServiceInfo;
  import org.geotools.data.ows.AbstractOpenWebService;
  import org.geotools.data.ows.Capabilities;
  import org.geotools.data.ows.OperationType;
  import org.geotools.http.HTTPClientFinder;
  import org.geotools.ows.wms.Layer;
  import org.geotools.ows.wms.WMSCapabilities;
  import org.geotools.ows.wms.WebMapServer;
  import org.geotools.ows.wmts.WebMapTileServer;
  import org.geotools.ows.wmts.model.WMTSLayer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.http.MediaType;
  import org.springframework.stereotype.Service;
  import org.springframework.util.CollectionUtils;
  import org.tailormap.api.configuration.TailormapConfig;
  import org.tailormap.api.geotools.ResponseTeeingHTTPClient;
  import org.tailormap.api.geotools.WMSServiceExceptionUtil;
  import org.tailormap.api.geotools.featuresources.WFSFeatureSourceHelper;
  import org.tailormap.api.geotools.wfs.SimpleWFSHelper;
  import org.tailormap.api.geotools.wfs.SimpleWFSLayerDescription;
  import org.tailormap.api.persistence.GeoService;
  import org.tailormap.api.persistence.TMFeatureSource;
  import org.tailormap.api.persistence.json.GeoServiceLayer;
  import org.tailormap.api.persistence.json.ServiceAuthentication;
  import org.tailormap.api.persistence.json.TMServiceCapabilitiesRequest;
  import org.tailormap.api.persistence.json.TMServiceCapabilitiesRequestGetFeatureInfo;
  import org.tailormap.api.persistence.json.TMServiceCapabilitiesRequestGetMap;
  import org.tailormap.api.persistence.json.TMServiceCaps;
  import org.tailormap.api.persistence.json.TMServiceCapsCapabilities;
  import org.tailormap.api.persistence.json.TMServiceInfo;
  import org.tailormap.api.persistence.json.WMSStyle;
  import org.tailormap.api.repository.FeatureSourceRepository;
  
  @Service
  public class GeoServiceHelper {
  
    private static final Logger logger =
        LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
    private final TailormapConfig tailormapConfig;
    private final FeatureSourceRepository featureSourceRepository;
  
    @Autowired
    public GeoServiceHelper(TailormapConfig tailormapConfig, FeatureSourceRepository featureSourceRepository) {
      this.tailormapConfig = tailormapConfig;
      this.featureSourceRepository = featureSourceRepository;
    }
  
    public org.tailormap.api.viewer.model.Service.ServerTypeEnum guessServerTypeFromUrl(String url) {
  
      if (StringUtils.isBlank(url)) {
        return org.tailormap.api.viewer.model.Service.ServerTypeEnum.GENERIC;
      }
      if (url.contains("/arcgis/")) {
        return org.tailormap.api.viewer.model.Service.ServerTypeEnum.GENERIC;
      }
      if (url.contains("/geoserver/")) {
        return org.tailormap.api.viewer.model.Service.ServerTypeEnum.GEOSERVER;
      }
      if (url.contains("/mapserv")) { // /cgi-bin/mapserv, /cgi-bin/mapserv.cgi, /cgi-bin/mapserv.fcgi
        return org.tailormap.api.viewer.model.Service.ServerTypeEnum.MAPSERVER;
      }
      return org.tailormap.api.viewer.model.Service.ServerTypeEnum.GENERIC;
    }
  
    public void loadServiceCapabilities(GeoService geoService) throws Exception {
  
      if (geoService.getProtocol() == XYZ) {
       setXyzCapabilities(geoService);
       return;
     }
 
     if (geoService.getProtocol() == TILES3D) {
       set3DTilesCapabilities(geoService);
       return;
     }
 
     if (geoService.getProtocol() == QUANTIZEDMESH) {
       setQuantizedMeshCapabilities(geoService);
       return;
     }
 
     ResponseTeeingHTTPClient client = new ResponseTeeingHTTPClient(
         HTTPClientFinder.createClient(), null, Set.of("Access-Control-Allow-Origin"));
 
     ServiceAuthentication auth = geoService.getAuthentication();
     if (auth != null && auth.getMethod() == ServiceAuthentication.MethodEnum.PASSWORD) {
       client.setUser(auth.getUsername());
       client.setPassword(auth.getPassword());
     }
 
     client.setReadTimeout(this.tailormapConfig.getTimeout());
     client.setConnectTimeout(this.tailormapConfig.getTimeout());
     client.setTryGzip(true);
 
     logger.info(
         "Get capabilities for {} {} from URL {}",
         geoService.getProtocol(),
         geoService.getId() == null ? "(new)" : "id " + geoService.getId(),
         geoService.getUrl());
 
     // TODO: micrometer met tags voor URL/id van service
 
     switch (geoService.getProtocol()) {
       case WMS:
         loadWMSCapabilities(geoService, client);
         break;
       case WMTS:
         loadWMTSCapabilities(geoService, client);
         break;
       default:
         throw new UnsupportedOperationException(
             "Unsupported geo service protocol: " + geoService.getProtocol());
     }
 
     if (geoService.getTitle() == null) {
       geoService.setTitle(Optional.ofNullable(geoService.getServiceCapabilities())
           .map(TMServiceCaps::getServiceInfo)
           .map(TMServiceInfo::getTitle)
           .orElse(null));
     }
 
     if (logger.isDebugEnabled()) {
       logger.debug("Loaded service layers: {}", geoService.getLayers());
     } else {
       logger.info(
           "Loaded service layers: {}",
           geoService.getLayers().stream()
               .filter(Predicate.not(GeoServiceLayer::getVirtual))
               .map(GeoServiceLayer::getName)
               .collect(Collectors.toList()));
     }
   }
 
   private static void setXyzCapabilities(GeoService geoService) {
     geoService.setLayers(List.of(new GeoServiceLayer()
         .id("0")
         .root(true)
         .name("xyz")
         .title(geoService.getTitle())
         .crs(Set.of(geoService.getSettings().getXyzCrs()))
         .virtual(false)
         .queryable(false)));
   }
 
   private static void set3DTilesCapabilities(GeoService geoService) {
     geoService.setLayers(List.of(new GeoServiceLayer()
         .id("0")
         .root(true)
         .name("tiles3d")
         .title(geoService.getTitle())
         .virtual(false)
         .queryable(false)));
   }
 
   private static void setQuantizedMeshCapabilities(GeoService geoService) {
     geoService.setLayers(List.of(new GeoServiceLayer()
         .id("0")
         .root(true)
         .name("quantizedmesh")
         .title(geoService.getTitle())
         .virtual(false)
         .queryable(false)));
   }
 
   private void setServiceInfo(
       GeoService geoService,
       ResponseTeeingHTTPClient client,
       AbstractOpenWebService<? extends Capabilities, Layer> ows) {
     geoService.setCapabilities(client.getLatestResponseCopy());
     geoService.setCapabilitiesContentType(MediaType.APPLICATION_XML_VALUE);
     // geoService.setCapabilitiesContentType(client.getResponse().getContentType());
     geoService.setCapabilitiesFetched(Instant.now());
 
     ServiceInfo info = ows.getInfo();
 
     TMServiceCaps caps = new TMServiceCaps();
     geoService.setServiceCapabilities(caps);
 
     caps.setCorsAllowOrigin(client.getLatestResponse().getResponseHeader("Access-Control-Allow-Origin"));
 
     if (info != null) {
       if (StringUtils.isBlank(geoService.getTitle())) {
         geoService.setTitle(info.getTitle());
       }
 
       caps.serviceInfo(new TMServiceInfo()
           .keywords(info.getKeywords())
           .description(info.getDescription())
           .title(info.getTitle())
           .publisher(info.getPublisher())
           .schema(info.getSchema())
           .source(info.getSource()));
 
       geoService.setAdvertisedUrl(info.getSource().toString());
     } else if (ows.getCapabilities() != null && ows.getCapabilities().getService() != null) {
       org.geotools.data.ows.Service service = ows.getCapabilities().getService();
 
       if (StringUtils.isBlank(geoService.getTitle())) {
         geoService.setTitle(service.getTitle());
       }
       caps.setServiceInfo(new TMServiceInfo().keywords(Set.copyOf(List.of(service.getKeywordList()))));
     }
   }
 
   private GeoServiceLayer toGeoServiceLayer(Layer l, List<? extends Layer> layers) {
     return new GeoServiceLayer()
         .id(String.valueOf(layers.indexOf(l)))
         .name(l.getName())
         .root(l.getParent() == null)
         .title(l.getTitle())
         .maxScale(Double.isNaN(l.getScaleDenominatorMax()) ? null : l.getScaleDenominatorMax())
         .minScale(Double.isNaN(l.getScaleDenominatorMin()) ? null : l.getScaleDenominatorMin())
         .virtual(l.getName() == null)
         .crs(l.getSrs())
         .latLonBoundingBox(GeoToolsHelper.boundsFromCRSEnvelope(l.getLatLonBoundingBox()))
         .styles(l.getStyles().stream()
             .map(gtStyle -> {
               WMSStyle style = new WMSStyle()
                   .name(gtStyle.getName())
                   .title(Optional.ofNullable(gtStyle.getTitle())
                       .map(Objects::toString)
                       .orElse(null))
                   .abstractText(Optional.ofNullable(gtStyle.getAbstract())
                       .map(Objects::toString)
                       .orElse(null));
               try {
                 List<?> legendURLs = gtStyle.getLegendURLs();
                 // GeoTools will replace invalid URLs with null in legendURLs
                 if (legendURLs != null && !legendURLs.isEmpty() && legendURLs.get(0) != null) {
                   style.legendURL(new URI((String) legendURLs.get(0)));
                 }
               } catch (URISyntaxException ignored) {
                 // Won't occur because GeoTools would have already returned null on
                 // invalid URL
               }
               return style;
             })
             .collect(Collectors.toList()))
         .queryable(l.isQueryable())
         .abstractText(l.get_abstract())
         .children(l.getLayerChildren().stream()
             .map(layers::indexOf)
             .map(String::valueOf)
             .collect(Collectors.toList()));
   }
 
   private void addLayerRecursive(
       GeoService geoService, List<? extends Layer> layers, Layer layer, Set<String> parentCrs) {
     GeoServiceLayer geoServiceLayer = toGeoServiceLayer(layer, layers);
     // Crses are inherited from the parent and this is applied by GeoTools so Layer.getSrs() has all
     // supported crses, but to save space we reverse that by only saving new crses for child layers
     // -- just like the original WMS capabilities.
     geoServiceLayer.getCrs().removeAll(parentCrs);
     geoService.getLayers().add(geoServiceLayer);
     for (Layer l : layer.getLayerChildren()) {
       addLayerRecursive(geoService, layers, l, layer.getSrs());
     }
   }
 
   void loadWMSCapabilities(GeoService geoService, ResponseTeeingHTTPClient client) throws Exception {
     WebMapServer wms;
     try {
       wms = new WebMapServer(new URL(geoService.getUrl()), client);
     } catch (ClassCastException | IllegalStateException e) {
       // The gt-wms module tries to cast the XML unmarshalling result expecting capabilities, but a
       // WMS 1.0.0/1.1.0 ServiceException may have been unmarshalled which leads to a
       // ClassCastException.
 
       // A WMS 1.3.0 ServiceExceptionReport leads to an IllegalStateException because of a call to
       // Throwable.initCause() on a SAXException that already has a cause.
 
       // In these cases, try to extract a message from the HTTP response
 
       String contentType = client.getLatestResponse().getContentType();
       if (contentType != null && contentType.contains("text/xml")) {
         String wmsException =
             WMSServiceExceptionUtil.tryGetServiceExceptionMessage(client.getLatestResponseCopy());
         throw new Exception("Error loading WMS capabilities: "
             + (wmsException != null
                 ? wmsException
                 : new String(client.getLatestResponseCopy(), StandardCharsets.UTF_8)));
       } else {
         throw e;
       }
     } catch (IOException e) {
       // This tries to match a HttpURLConnection (which the default GeoTools SimpleHTTPClient uses)
       // exception message. In a container environment the JVM is always in English so never
       // localized.
       if (e.getMessage().contains("Server returned HTTP response code: 401 for URL:")) {
         throw new Exception(
             "Error loading WMS, got 401 unauthorized response (credentials may be required or invalid)");
       } else {
         throw e;
       }
     }
 
     OperationType getMap = wms.getCapabilities().getRequest().getGetMap();
     OperationType getFeatureInfo = wms.getCapabilities().getRequest().getGetFeatureInfo();
 
     if (getMap == null) {
       throw new Exception("Service does not support GetMap");
     }
 
     setServiceInfo(geoService, client, wms);
 
     WMSCapabilities wmsCapabilities = wms.getCapabilities();
 
     // TODO Jackson annotations op GeoTools classes of iets anders slims?
 
     geoService
         .getServiceCapabilities()
         .capabilities(new TMServiceCapsCapabilities()
             .version(wmsCapabilities.getVersion())
             .updateSequence(wmsCapabilities.getUpdateSequence())
             .abstractText(wmsCapabilities.getService().get_abstract())
             .request(new TMServiceCapabilitiesRequest()
                 .getMap(new TMServiceCapabilitiesRequestGetMap()
                     .formats(Set.copyOf(getMap.getFormats())))
                 .getFeatureInfo(
                     getFeatureInfo == null
                         ? null
                         : new TMServiceCapabilitiesRequestGetFeatureInfo()
                             .formats(Set.copyOf(getFeatureInfo.getFormats())))
                 .describeLayer(
                     wms.getCapabilities().getRequest().getDescribeLayer() != null)));
 
     if (logger.isDebugEnabled()) {
       logger.debug("Loaded capabilities, service capabilities: {}", geoService.getServiceCapabilities());
     } else {
       logger.info(
           "Loaded capabilities from \"{}\", title: \"{}\"",
           geoService.getUrl(),
           geoService.getServiceCapabilities() != null
                   && geoService.getServiceCapabilities().getServiceInfo() != null
               ? geoService
                   .getServiceCapabilities()
                   .getServiceInfo()
                   .getTitle()
               : "(none)");
     }
     geoService.setLayers(new ArrayList<>());
     addLayerRecursive(
         geoService,
         wms.getCapabilities().getLayerList(),
         wms.getCapabilities().getLayer(),
         Collections.emptySet());
   }
 
   void loadWMTSCapabilities(GeoService geoService, ResponseTeeingHTTPClient client) throws Exception {
     WebMapTileServer wmts = new WebMapTileServer(new URL(geoService.getUrl()), client);
     setServiceInfo(geoService, client, wmts);
 
     // TODO set capabilities if we need something from it
 
     List<WMTSLayer> layers = wmts.getCapabilities().getLayerList();
     geoService.setLayers(
         layers.stream().map(l -> toGeoServiceLayer(l, layers)).collect(Collectors.toList()));
   }
 
   public Map<String, SimpleWFSLayerDescription> findRelatedWFS(GeoService geoService) {
     // TODO: report back progress
 
     if (CollectionUtils.isEmpty(geoService.getLayers())) {
       return Collections.emptyMap();
     }
 
     // Do one DescribeLayer request for all layers in a WMS. This is faster than one request per
     // layer, but when one layer has an error this prevents describing valid layers. But that's a
     // problem with the WMS / GeoServer.
     // For now at least ignore layers with space in the name because GeoServer chokes out invalid
     // XML for those.
 
     List<String> layers = geoService.getLayers().stream()
         .filter(l -> !l.getVirtual())
         .map(GeoServiceLayer::getName)
         .filter(n -> {
           // filter out white-space (non-greedy regex)
           boolean noWhitespace = !n.contains("(.*?)\\s(.*?)");
           if (!noWhitespace) {
             logger.warn(
                 "Not doing WFS DescribeLayer request for layer name with space: \"{}\" of WMS {}",
                 n,
                 geoService.getUrl());
           }
           return noWhitespace;
         })
         .collect(Collectors.toList());
 
     // TODO: add authentication
     Map<String, SimpleWFSLayerDescription> descriptions =
         SimpleWFSHelper.describeWMSLayers(geoService.getUrl(), null, null, layers);
 
     for (Map.Entry<String, SimpleWFSLayerDescription> entry : descriptions.entrySet()) {
       String layerName = entry.getKey();
       SimpleWFSLayerDescription description = entry.getValue();
       if (description.typeNames().size() == 1 && layerName.equals(description.getFirstTypeName())) {
         logger.info(
             "layer \"{}\" linked to feature type with same name of WFS {}",
             layerName,
             description.wfsUrl());
       } else {
         logger.info(
             "layer \"{}\" -> feature type(s) {} of WFS {}",
             layerName,
             description.typeNames(),
             description.wfsUrl());
       }
     }
     return descriptions;
   }
 
   public void findAndSaveRelatedWFS(GeoService geoService) {
     if (geoService.getProtocol() != WMS) {
       throw new IllegalArgumentException();
     }
 
     // TODO: report back progress
 
     Map<String, SimpleWFSLayerDescription> wfsByLayer = this.findRelatedWFS(geoService);
 
     wfsByLayer.values().stream()
         .map(SimpleWFSLayerDescription::wfsUrl)
         .distinct()
         .forEach(url -> {
           TMFeatureSource fs = featureSourceRepository.findByUrl(url);
           if (fs == null) {
             fs = new TMFeatureSource()
                 .setProtocol(WFS)
                 .setUrl(url)
                 .setTitle("WFS for " + geoService.getTitle())
                 .setLinkedService(geoService);
             try {
               new WFSFeatureSourceHelper().loadCapabilities(fs, tailormapConfig.getTimeout());
             } catch (IOException e) {
               String msg = String.format(
                   "Error loading WFS from URL %s: %s: %s", url, e.getClass(), e.getMessage());
               if (logger.isTraceEnabled()) {
                 logger.error(msg, e);
               } else {
                 logger.error(msg);
               }
             }
             featureSourceRepository.save(fs);
           }
         });
   }
 
   /**
    * Try to extract the legend url from the styles of the layer. This works by getting all styles for the layer and
    * then removing any styles attached to other (parent) layers from the list of all styles. What remains is/are the
    * legend url(s) for the layer. <i>NOTE: when a layer has more than one -not an inherited style- style the first
    * style is used.</i>
    *
    * @param service the service that has the layer
    * @param serviceLayer the layer to get the legend url for
    * @return a URI to the legend image or null if not found
    */
   public static URI getLayerLegendUrlFromStyles(GeoService service, GeoServiceLayer serviceLayer) {
     if (serviceLayer.getRoot()) {
       // if this is a root layer, there are no parent layers, return the first style we find for
       // this layer, if any
       return serviceLayer.getStyles().stream()
           .findFirst()
           .map(WMSStyle::getLegendURL)
           .orElse(null);
     }
 
     final List<WMSStyle> allOurLayersStyles = serviceLayer.getStyles();
     if (allOurLayersStyles.size() == 1) {
       return allOurLayersStyles.get(0).getLegendURL();
     }
     // remove the styles from all the other layer(s) from the list of all our layers styles
     service.getLayers().stream()
         .filter(layer -> !layer.equals(serviceLayer))
         .forEach(layer -> allOurLayersStyles.removeAll(layer.getStyles()));
 
     return allOurLayersStyles.stream()
         .findFirst()
         .map(WMSStyle::getLegendURL)
         .orElse(null);
   }
 }