/*
    * Copyright (C) 2023 B3Partners B.V.
    *
    * SPDX-License-Identifier: MIT
    */
   package org.tailormap.api.controller;
   
   import static org.springframework.web.bind.annotation.RequestMethod.GET;
   import static org.springframework.web.bind.annotation.RequestMethod.POST;
  import static org.tailormap.api.persistence.helper.TMFeatureTypeHelper.getConfiguredAttributes;
  import static org.tailormap.api.util.HttpProxyUtil.passthroughResponseHeaders;
  
  import io.micrometer.core.annotation.Counted;
  import io.micrometer.core.annotation.Timed;
  import jakarta.servlet.http.HttpServletRequest;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Serializable;
  import java.lang.invoke.MethodHandles;
  import java.net.URI;
  import java.net.http.HttpResponse;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import org.geotools.api.feature.type.AttributeDescriptor;
  import org.geotools.data.wfs.WFSDataStore;
  import org.geotools.data.wfs.WFSDataStoreFactory;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Value;
  import org.springframework.core.io.InputStreamResource;
  import org.springframework.http.HttpStatus;
  import org.springframework.http.ResponseEntity;
  import org.springframework.transaction.annotation.Transactional;
  import org.springframework.util.CollectionUtils;
  import org.springframework.util.LinkedMultiValueMap;
  import org.springframework.util.MultiValueMap;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.ModelAttribute;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RequestParam;
  import org.springframework.web.server.ResponseStatusException;
  import org.tailormap.api.annotation.AppRestController;
  import org.tailormap.api.geotools.PreventLocalAllowNestedJarEntityResolver;
  import org.tailormap.api.geotools.wfs.SimpleWFSHelper;
  import org.tailormap.api.geotools.wfs.SimpleWFSLayerDescription;
  import org.tailormap.api.geotools.wfs.WFSProxy;
  import org.tailormap.api.persistence.Application;
  import org.tailormap.api.persistence.GeoService;
  import org.tailormap.api.persistence.TMFeatureSource;
  import org.tailormap.api.persistence.TMFeatureType;
  import org.tailormap.api.persistence.json.AppLayerSettings;
  import org.tailormap.api.persistence.json.AppTreeLayerNode;
  import org.tailormap.api.persistence.json.GeoServiceLayer;
  import org.tailormap.api.persistence.json.GeoServiceProtocol;
  import org.tailormap.api.persistence.json.ServiceAuthentication;
  import org.tailormap.api.repository.FeatureSourceRepository;
  import org.tailormap.api.viewer.model.LayerExportCapabilities;
  
  @AppRestController
  @RequestMapping(path = "${tailormap-api.base-path}/{viewerKind}/{viewerName}/layer/{appLayerId}/export/")
  public class LayerExportController {
    private static final Logger logger =
        LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    @Value("#{'${tailormap-api.export.allowed-outputformats}'.split(',')}")
    private List<String> allowedOutputFormats;
  
    private final FeatureSourceRepository featureSourceRepository;
    private final WFSProxy wfsProxy = new WFSProxy();
  
    public LayerExportController(FeatureSourceRepository featureSourceRepository) {
      this.featureSourceRepository = featureSourceRepository;
    }
  
    @Transactional
    @GetMapping(path = "capabilities")
    @Timed(value = "export_get_capabilities", description = "Get layer export capabilities")
    public ResponseEntity<Serializable> capabilities(
        @ModelAttribute GeoService service, @ModelAttribute GeoServiceLayer layer) {
  
      final LayerExportCapabilities capabilities = new LayerExportCapabilities().exportable(false);
  
      TMFeatureType tmft = service.findFeatureTypeForLayer(layer, featureSourceRepository);
  
      if (tmft != null) {
        WFSTypeNameDescriptor wfsTypeNameDescriptor = findWFSFeatureType(service, layer, tmft);
  
        if (wfsTypeNameDescriptor != null) {
          try {
            List<String> outputFormats = SimpleWFSHelper.getOutputFormats(
                wfsTypeNameDescriptor.wfsUrl(),
                wfsTypeNameDescriptor.typeName(),
                wfsTypeNameDescriptor.username(),
                wfsTypeNameDescriptor.password());
            capabilities.setOutputFormats(outputFormats);
          } catch (Exception e) {
           String msg = "Error getting capabilities for WFS \"%s\"".formatted(wfsTypeNameDescriptor.wfsUrl());
           if (logger.isTraceEnabled()) {
             logger.trace(msg, e);
           } else {
             logger.warn("{}: {}: {}", msg, e.getClass(), e.getMessage());
           }
           capabilities.setOutputFormats(null);
         }
       }
       capabilities.setExportable(capabilities.getOutputFormats() != null
           && !capabilities.getOutputFormats().isEmpty());
     }
 
     return ResponseEntity.status(HttpStatus.OK).body(capabilities);
   }
 
   @Transactional
   @RequestMapping(
       path = "download",
       method = {GET, POST})
   @Counted(value = "export_download", description = "Count of layer downloads")
   public ResponseEntity<?> download(
       @ModelAttribute GeoService service,
       @ModelAttribute GeoServiceLayer layer,
       @ModelAttribute Application application,
       @ModelAttribute AppTreeLayerNode appTreeLayerNode,
       @RequestParam String outputFormat,
       @RequestParam(required = false) Set<String> attributes,
       @RequestParam(required = false) String filter,
       @RequestParam(required = false) String sortBy,
       @RequestParam(required = false) String sortOrder,
       @RequestParam(required = false) String crs,
       HttpServletRequest request) {
 
     // Validate outputFormat
     if (!allowedOutputFormats.contains(outputFormat)) {
       logger.warn("Invalid output format requested: {}", outputFormat);
       return ResponseEntity.status(HttpStatus.BAD_REQUEST).body("Invalid output format");
     }
 
     TMFeatureType tmft = service.findFeatureTypeForLayer(layer, featureSourceRepository);
     AppLayerSettings appLayerSettings = application.getAppLayerSettings(appTreeLayerNode);
 
     if (tmft == null) {
       logger.debug("Layer export requested for layer without feature type");
       throw new ResponseStatusException(HttpStatus.NOT_FOUND);
     }
 
     // Find a WFS feature type either because it is configured in Tailormap or by a SLD
     // DescribeLayer request
     WFSTypeNameDescriptor wfsTypeNameDescriptor = findWFSFeatureType(service, layer, tmft);
 
     if (wfsTypeNameDescriptor == null) {
       throw new ResponseStatusException(
           HttpStatus.SERVICE_UNAVAILABLE, "No suitable WFS available for layer export");
     }
 
     if (attributes == null) {
       attributes = new HashSet<>();
     }
 
     // Get attributes in configured or original order
     Set<String> nonHiddenAttributes =
         getConfiguredAttributes(tmft, appLayerSettings).keySet();
 
     if (!attributes.isEmpty()) {
       // Only export non-hidden property names
       if (!nonHiddenAttributes.containsAll(attributes)) {
         throw new ResponseStatusException(
             HttpStatus.BAD_REQUEST,
             "One or more requested attributes are not available on the feature type");
       }
     } else if (!tmft.getSettings().getHideAttributes().isEmpty()) {
       // Only specify specific propNames if there are hidden attributes. Having no propNames
       // request parameter to request all propNames is less error-prone than specifying the ones
       // we have saved in the feature type
       attributes = new HashSet<>(nonHiddenAttributes);
     }
 
     // Empty attributes means we won't specify propNames in the GetFeature request. However, if we do select only
     // some property names, we need the geometry attribute which is not in the 'attributes' request param so spatial
     // export formats don't have the geometry missing.
     if (!attributes.isEmpty() && tmft.getDefaultGeometryAttribute() != null) {
       attributes.add(tmft.getDefaultGeometryAttribute());
     }
 
     // Remove attributes which the WFS does not expose. This can be the case when using the
     // 'customize attributes' feature in GeoServer but when TM has been configured with a JDBC
     // feature type with all the attributes. Requesting a non-existing attribute will return an
     // error.
     try {
       List<String> wfsAttributeNames = getWFSAttributeNames(wfsTypeNameDescriptor);
       attributes.retainAll(wfsAttributeNames);
       // SSRF prevention: only allow known-safe attribute names
       attributes.removeIf(attr -> !attr.matches("^[A-Za-z0-9_]+$"));
       if (!CollectionUtils.isEmpty(attributes)
           && attributes.stream().anyMatch(attr -> !wfsAttributeNames.contains(attr))) {
         logger.warn("Download request contained illegal attribute(s)");
         return ResponseEntity.status(HttpStatus.BAD_REQUEST).body("Invalid attribute selection");
       }
     } catch (IOException e) {
       logger.error("Error getting WFS feature type", e);
       return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Error getting WFS feature type");
     }
 
     return downloadFromWFS(
         wfsTypeNameDescriptor, outputFormat, attributes, filter, sortBy, sortOrder, crs, request);
   }
 
   private ResponseEntity<?> downloadFromWFS(
       WFSTypeNameDescriptor wfsTypeName,
       String outputFormat,
       Set<String> attributes,
       String filter,
       String sortBy,
       String sortOrder,
       String crs,
       HttpServletRequest request) {
 
     MultiValueMap<String, String> getFeatureParameters = new LinkedMultiValueMap<>();
     // A layer could have more than one featureType as source, currently we assume it's just one
     getFeatureParameters.add("typeNames", wfsTypeName.typeName());
     getFeatureParameters.add("outputFormat", outputFormat);
     if (filter != null) {
       // GeoServer vendor-specific
       // https://docs.geoserver.org/latest/en/user/services/wfs/vendor.html#cql-filters
       getFeatureParameters.add("cql_filter", filter);
     }
     if (crs != null) {
       getFeatureParameters.add("srsName", crs);
     }
     if (!CollectionUtils.isEmpty(attributes)) {
       getFeatureParameters.add("propertyName", String.join(",", attributes));
     }
     if (sortBy != null) {
       getFeatureParameters.add("sortBy", sortBy + ("asc".equals(sortOrder) ? " A" : " D"));
     }
     URI wfsGetFeature = SimpleWFSHelper.getWFSRequestURL(wfsTypeName.wfsUrl(), "GetFeature", getFeatureParameters);
 
     logger.info("Layer download, proxying WFS GetFeature request {}", wfsGetFeature);
     try {
       // TODO: close JPA connection before proxying
       HttpResponse<InputStream> response =
           wfsProxy.proxyWfsRequest(wfsGetFeature, wfsTypeName.username(), wfsTypeName.password(), request);
 
       logger.info(
           "Layer download response code: {}, content type: {}, disposition: {}",
           response.statusCode(),
           response.headers()
               .firstValue("Content-Type")
               .map(Object::toString)
               .orElse("<none>"),
           response.headers()
               .firstValue("Content-Disposition")
               .map(Object::toString)
               .orElse("<none>"));
 
       InputStreamResource body = new InputStreamResource(response.body());
 
       org.springframework.http.HttpHeaders headers =
           passthroughResponseHeaders(response.headers(), Set.of("Content-Type", "Content-Disposition"));
 
       // TODO: record response size and time with micrometer
       return ResponseEntity.status(response.statusCode()).headers(headers).body(body);
     } catch (Exception e) {
       return ResponseEntity.status(HttpStatus.BAD_GATEWAY).body("Bad Gateway");
     }
   }
 
   private record WFSTypeNameDescriptor(String wfsUrl, String typeName, String username, String password) {}
 
   private WFSTypeNameDescriptor findWFSFeatureType(GeoService service, GeoServiceLayer layer, TMFeatureType tmft) {
 
     String wfsUrl = null;
     String typeName = null;
     String username = null;
     String password = null;
     ServiceAuthentication auth = null;
 
     if (tmft != null) {
       TMFeatureSource featureSource = tmft.getFeatureSource();
 
       if (featureSource.getProtocol() == TMFeatureSource.Protocol.WFS) {
         wfsUrl = featureSource.getUrl();
         typeName = tmft.getName();
         auth = featureSource.getAuthentication();
       }
     }
 
     if ((wfsUrl == null || typeName == null) && service.getProtocol() == GeoServiceProtocol.WMS) {
       // Try to find out the WFS by doing a DescribeLayer request (from OGC SLD spec)
       auth = service.getAuthentication();
 
       SimpleWFSLayerDescription wfsLayerDescription = getWFSLayerDescriptionForWMS(service, layer.getName());
       if (wfsLayerDescription != null
           && wfsLayerDescription.wfsUrl() != null
           && wfsLayerDescription.getFirstTypeName() != null) {
         wfsUrl = wfsLayerDescription.wfsUrl();
         // Ignores possibly multiple feature types associated with the layer (a group layer for
         // instance)
         typeName = wfsLayerDescription.getFirstTypeName();
         auth = service.getAuthentication();
       }
     }
 
     if (auth != null && auth.getMethod() == ServiceAuthentication.MethodEnum.PASSWORD) {
       username = auth.getUsername();
       password = auth.getPassword();
     }
 
     if (wfsUrl != null && typeName != null) {
       return new WFSTypeNameDescriptor(wfsUrl, typeName, username, password);
     } else {
       return null;
     }
   }
 
   private SimpleWFSLayerDescription getWFSLayerDescriptionForWMS(GeoService wmsService, String layerName) {
     String username = null;
     String password = null;
     if (wmsService.getAuthentication() != null
         && wmsService.getAuthentication().getMethod() == ServiceAuthentication.MethodEnum.PASSWORD) {
       username = wmsService.getAuthentication().getUsername();
       password = wmsService.getAuthentication().getPassword();
     }
     SimpleWFSLayerDescription wfsLayerDescription =
         SimpleWFSHelper.describeWMSLayer(wmsService.getUrl(), username, password, layerName);
     if (wfsLayerDescription != null && !wfsLayerDescription.typeNames().isEmpty()) {
       logger.info(
           "WMS described layer \"{}\" with typeNames \"{}\" of WFS \"{}\" for WMS \"{}\"",
           layerName,
           wfsLayerDescription.typeNames(),
           wfsLayerDescription.wfsUrl(),
           wmsService.getUrl());
 
       return wfsLayerDescription;
     }
     return null;
   }
 
   /**
    * Get the (exposed) attribute names of the WFS feature type.
    *
    * @param wfsTypeNameDescriptor provides the WFS feature type to get the attribute names for
    * @return a list of attribute names for the WFS feature type
    * @throws IOException if there were any problems setting up (creating or connecting) the datasource.
    */
   private static List<String> getWFSAttributeNames(WFSTypeNameDescriptor wfsTypeNameDescriptor) throws IOException {
     Map<String, Object> connectionParameters = new HashMap<>();
     connectionParameters.put(
         WFSDataStoreFactory.ENTITY_RESOLVER.key, PreventLocalAllowNestedJarEntityResolver.INSTANCE);
     connectionParameters.put(
         WFSDataStoreFactory.URL.key,
         SimpleWFSHelper.getWFSRequestURL(wfsTypeNameDescriptor.wfsUrl(), "GetCapabilities")
             .toURL());
     connectionParameters.put(WFSDataStoreFactory.PROTOCOL.key, false);
     connectionParameters.put(WFSDataStoreFactory.WFS_STRATEGY.key, "geoserver");
     connectionParameters.put(WFSDataStoreFactory.LENIENT.key, true);
     connectionParameters.put(WFSDataStoreFactory.TIMEOUT.key, SimpleWFSHelper.TIMEOUT);
     if (wfsTypeNameDescriptor.username() != null) {
       connectionParameters.put(WFSDataStoreFactory.USERNAME.key, wfsTypeNameDescriptor.username());
       connectionParameters.put(WFSDataStoreFactory.PASSWORD.key, wfsTypeNameDescriptor.password());
     }
 
     WFSDataStore wfs = new WFSDataStoreFactory().createDataStore(connectionParameters);
     List<String> attributeNames =
         wfs.getFeatureSource(wfsTypeNameDescriptor.typeName()).getSchema().getAttributeDescriptors().stream()
             .map(AttributeDescriptor::getLocalName)
             .toList();
 
     wfs.dispose();
     return attributeNames;
   }
 }