/*
    * Copyright 2012-2025 CodeLibs Project and the Others.
    *
    * 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.
   */
  package org.codelibs.fess.app.web.go;
  
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.util.Map;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.codelibs.core.lang.StringUtil;
  import org.codelibs.core.net.URLUtil;
  import org.codelibs.fess.Constants;
  import org.codelibs.fess.app.web.base.FessSearchAction;
  import org.codelibs.fess.app.web.error.ErrorAction;
  import org.codelibs.fess.crawler.util.CharUtil;
  import org.codelibs.fess.helper.PathMappingHelper;
  import org.codelibs.fess.helper.SearchLogHelper;
  import org.codelibs.fess.helper.ViewHelper;
  import org.codelibs.fess.opensearch.log.exentity.ClickLog;
  import org.codelibs.fess.util.ComponentUtil;
  import org.codelibs.fess.util.DocumentUtil;
  import org.dbflute.util.DfTypeUtil;
  import org.lastaflute.web.Execute;
  import org.lastaflute.web.response.ActionResponse;
  import org.lastaflute.web.response.HtmlResponse;
  import org.lastaflute.web.response.StreamResponse;
  
  import jakarta.annotation.Resource;
  
  /**
   * Action class for handling document redirection requests.
   * This action processes "go" requests that redirect users to specific documents
   * while tracking click events and handling various URL types including file system paths.
   */
  public class GoAction extends FessSearchAction {
  
      /**
       * Default constructor for GoAction.
       */
      public GoAction() {
          super();
      }
  
      // ===================================================================================
      //                                                                            Constant
      //
      /** Logger for this class. */
      private static final Logger logger = LogManager.getLogger(GoAction.class);
  
      /** Helper for URL path mapping and transformation. */
      @Resource
      protected PathMappingHelper pathMappingHelper;
  
      // ===================================================================================
      //                                                                           Attribute
      //
  
      // ===================================================================================
      //                                                                               Hook
      //                                                                              ======
  
      // ===================================================================================
      //                                                                      Search Execute
      //                                                                      ==============
      /**
       * Handles document redirection requests.
       * Validates the document ID, logs click events if enabled, and redirects
       * to the target URL or serves file content directly if configured.
       *
       * @param form the go form containing document ID and tracking parameters
       * @return action response for redirection or content streaming
       * @throws IOException if an I/O error occurs during content retrieval
       */
      @Execute
      public ActionResponse index(final GoForm form) throws IOException {
          validate(form, messages -> {}, () -> asHtml(virtualHost(path_Error_ErrorJsp)));
          if (isLoginRequired()) {
              return redirectToLogin();
          }
  
          Map<String, Object> doc = null;
          try {
              doc = searchHelper
                      .getDocumentByDocId(form.docId, new String[] { fessConfig.getIndexFieldUrl(), fessConfig.getIndexFieldConfigId() },
                             getUserBean())
                     .orElse(null);
         } catch (final Exception e) {
             logger.warn("Failed to request: {}", form.docId, e);
         }
         if (doc == null) {
             saveError(messages -> messages.addErrorsDocidNotFound(GLOBAL, form.docId));
             return redirect(ErrorAction.class);
         }
         final String url = DocumentUtil.getValue(doc, fessConfig.getIndexFieldUrl(), String.class);
         if (url == null) {
             saveError(messages -> messages.addErrorsDocumentNotFound(GLOBAL, form.docId));
             return redirect(ErrorAction.class);
         }
 
         if (fessConfig.isSearchLog()) {
             final String userSessionId = userInfoHelper.getUserCode();
             if (userSessionId != null) {
                 final SearchLogHelper searchLogHelper = ComponentUtil.getSearchLogHelper();
                 final ClickLog clickLog = new ClickLog();
                 clickLog.setUrlId((String) doc.get(fessConfig.getIndexFieldId()));
                 clickLog.setUrl(url);
                 clickLog.setRequestedAt(systemHelper.getCurrentTimeAsLocalDateTime());
                 clickLog.setQueryRequestedAt(DfTypeUtil.toLocalDateTime(Long.parseLong(form.rt)));
                 clickLog.setUserSessionId(userSessionId);
                 clickLog.setDocId(form.docId);
                 clickLog.setQueryId(form.queryId);
                 if (form.order != null) {
                     clickLog.setOrder(form.order);
                 }
                 searchLogHelper.addClickLog(clickLog);
             }
         }
 
         final String targetUrl = pathMappingHelper.replaceUrl(url);
 
         String hash;
         if (StringUtil.isNotBlank(form.hash)) {
             final String value = URLUtil.decode(form.hash, Constants.UTF_8);
             if (targetUrl.indexOf('#') == -1) {
                 final StringBuilder buf = new StringBuilder(value.length() + 100);
                 for (final char c : value.toCharArray()) {
                     if (CharUtil.isUrlChar(c) || c == ' ') {
                         buf.append(c);
                     } else {
                         try {
                             buf.append(URLEncoder.encode(String.valueOf(c), Constants.UTF_8));
                         } catch (final UnsupportedEncodingException e) {
                             // NOP
                         }
                     }
                 }
                 hash = buf.toString();
             } else {
                 hash = StringUtil.EMPTY;
             }
         } else {
             hash = StringUtil.EMPTY;
         }
 
         if (!isFileSystemPath(targetUrl)) {
             if (isValidRedirectUrl(targetUrl)) {
                 return HtmlResponse.fromRedirectPathAsIs(DocumentUtil.encodeUrl(targetUrl + hash));
             } else {
                 logger.warn("Invalid redirect URL detected: {}", targetUrl);
                 saveError(messages -> messages.addErrorsDocumentNotFound(GLOBAL, form.docId));
                 return redirect(ErrorAction.class);
             }
         }
         if (!fessConfig.isSearchFileProxyEnabled()) {
             return HtmlResponse.fromRedirectPathAsIs(targetUrl + hash);
         }
         final ViewHelper viewHelper = ComponentUtil.getViewHelper();
         try {
             final StreamResponse response = viewHelper.asContentResponse(doc);
             if (response.getHttpStatus().orElse(200) == 404) {
                 logger.debug("Document not found: url={}", targetUrl);
                 saveError(messages -> messages.addErrorsNotFoundOnFileSystem(GLOBAL, targetUrl));
                 return redirect(ErrorAction.class);
             }
             return response;
         } catch (final Exception e) {
             logger.warn("Failed to load: {}", doc, e);
             saveError(messages -> messages.addErrorsNotLoadFromServer(GLOBAL, targetUrl));
             return redirect(ErrorAction.class);
         }
     }
 
     /**
      * Checks if the given URL represents a file system path.
      * Determines if the URL uses file system protocols that may require
      * special handling for content serving.
      *
      * @param url the URL to check
      * @return true if the URL is a file system path, false otherwise
      */
     protected boolean isFileSystemPath(final String url) {
         return ComponentUtil.getProtocolHelper().isFileSystemPath(url);
     }
 
     /**
      * Validates if the URL is safe for redirection.
      *
      * @param url the URL to validate
      * @return true if the URL is valid for redirection, false otherwise
      */
     protected boolean isValidRedirectUrl(final String url) {
         if (StringUtil.isBlank(url)) {
             return false;
         }
         final String lowerUrl = url.toLowerCase();
         if (lowerUrl.startsWith("http://") || lowerUrl.startsWith("https://")) {
             return true;
         }
         if (lowerUrl.startsWith("javascript:") || lowerUrl.startsWith("data:") || lowerUrl.startsWith("vbscript:")) {
             return false;
         }
         return true;
     }
 }