/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.juneau.bean.openapi3.ui;

import static org.apache.juneau.bean.html5.HtmlBuilder.*;
import static org.apache.juneau.bean.html5.HtmlBuilder.a;
import static org.apache.juneau.commons.http.MediaType.*;
import static org.apache.juneau.commons.utils.Shorts.*;

import org.apache.juneau.bean.html5.*;
import org.apache.juneau.bean.openapi3.*;
import org.apache.juneau.commons.http.MediaType;
import org.apache.juneau.commons.inject.*;
import org.apache.juneau.marshall.*;
import org.apache.juneau.marshall.cp.*;
import org.apache.juneau.marshall.swap.spi.*;

/**
 * Generates a Redoc-style documentation interface from an OpenAPI 3.1 document.
 *
 * <p>
 * Renders a two-column layout — a left sidebar containing the operation table-of-contents and a right
 * content panel with full operation descriptions, parameters, request/response schemas, and components.
 *
 * <p>
 * This is a sibling of {@link OpenApiUI} that provides a documentation-page-style rendering rather
 * than the interactive collapsing-block layout. Both are server-rendered HTML — neither bundles
 * external JavaScript packages.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauBeanOpenApi3">juneau-bean-openapi-v3</a>
 * </ul>
 */
@SuppressWarnings({
   "java:S1192" // String literals repeated for clarity in UI generation
})
public class RedocUI extends ObjectSwap<OpenApi,Div> {

   // @formatter:off
   static final FileFinder RESOURCES = FileFinder
      .create(BasicBeanStore.INSTANCE)
      .cp(RedocUI.class, null, true)
      .dir(",")
      .caching(Boolean.getBoolean("RestContext.disableClasspathResourceCaching.b") ? -1 : 1_000_000)
      .build();
   // @formatter:on

   @Override
   public MediaType[] forMediaTypes() {
      return new MediaType[] { HTML };
   }

   @Override
   public Div swap(MarshallingSession session, OpenApi openApi) throws Exception {
      var css = RESOURCES.getString("files/htdocs/styles/RedocUI.css", null)
         .orElse(RESOURCES.getString("RedocUI.css", null).orElse(DEFAULT_CSS));

      var sidebar = sidebar(openApi);
      var content = content(openApi);

      return div(style(css), div(sidebar, content).class_("redoc-container")).class_("redoc-ui");
   }

   private static Div sidebar(OpenApi openApi) {
      var nav = div().class_("redoc-sidebar");
      var info = openApi.getInfo();
      if (nn(info) && nn(info.getTitle()))
         nav.child(div(info.getTitle()).class_("redoc-title"));

      var paths = openApi.getPaths();
      if (nn(paths)) {
         var ul = ul().class_("redoc-toc");
         paths.forEach((path, pathItem) -> appendOperations(ul, path, pathItem));
         nav.child(ul);
      }
      if (nn(openApi.getComponents()) && nn(openApi.getComponents().getSchemas())) {
         var ul = ul().class_("redoc-toc redoc-models-toc");
         ul.child(li(div("Models").class_("redoc-section-title")));
         openApi.getComponents().getSchemas().forEach((name, schema) -> ul.child(li(a("#model-" + name, name))));
         nav.child(ul);
      }
      return nav;
   }

   private static void appendOperations(Ul ul, String path, PathItem item) {
      appendOperation(ul, path, "GET", item.getGet());
      appendOperation(ul, path, "PUT", item.getPut());
      appendOperation(ul, path, "POST", item.getPost());
      appendOperation(ul, path, "DELETE", item.getDelete());
      appendOperation(ul, path, "PATCH", item.getPatch());
      appendOperation(ul, path, "HEAD", item.getHead());
      appendOperation(ul, path, "OPTIONS", item.getOptions());
      appendOperation(ul, path, "TRACE", item.getTrace());
   }

   private static void appendOperation(Ul ul, String path, String verb, Operation op) {
      if (op == null)
         return;
      var anchor = "op-" + lcr(verb) + "-" + path.replaceAll("[^A-Za-z0-9]", "_");
      var label = nn(op.getSummary()) ? op.getSummary() : verb + " " + path;
      ul.child(li(span(verb).class_("redoc-method redoc-method-" + lcr(verb)), a("#" + anchor, label)));
   }

   private static Div content(OpenApi openApi) {
      var contentDiv = div().class_("redoc-content");
      var info = openApi.getInfo();
      if (nn(info)) {
         if (nn(info.getTitle()))
            contentDiv.child(h1(info.getTitle()));
         if (nn(info.getVersion()))
            contentDiv.child(div("Version: " + info.getVersion()).class_("redoc-version"));
         if (nn(info.getDescription()))
            contentDiv.child(div(info.getDescription()).class_("redoc-description"));
      }

      var paths = openApi.getPaths();
      if (nn(paths))
         paths.forEach((path, pathItem) -> renderPathOperations(contentDiv, path, pathItem));

      if (nn(openApi.getComponents()) && nn(openApi.getComponents().getSchemas())) {
         contentDiv.child(h2("Models"));
         openApi.getComponents().getSchemas().forEach((name, schema) -> {
            contentDiv.child(h3(name).id("model-" + name));
            if (nn(schema.getDescription()))
               contentDiv.child(div(schema.getDescription()).class_("redoc-model-desc"));
         });
      }
      return contentDiv;
   }

   private static void renderPathOperations(Div contentDiv, String path, PathItem item) {
      renderOperation(contentDiv, path, "GET", item.getGet());
      renderOperation(contentDiv, path, "PUT", item.getPut());
      renderOperation(contentDiv, path, "POST", item.getPost());
      renderOperation(contentDiv, path, "DELETE", item.getDelete());
      renderOperation(contentDiv, path, "PATCH", item.getPatch());
      renderOperation(contentDiv, path, "HEAD", item.getHead());
      renderOperation(contentDiv, path, "OPTIONS", item.getOptions());
      renderOperation(contentDiv, path, "TRACE", item.getTrace());
   }

   private static void renderOperation(Div contentDiv, String path, String verb, Operation op) {
      if (op == null)
         return;
      var anchor = "op-" + lcr(verb) + "-" + path.replaceAll("[^A-Za-z0-9]", "_");
      contentDiv.child(div(
         h2(verb + " " + path).id(anchor).class_("redoc-op-title redoc-op-title-" + lcr(verb)),
         nn(op.getSummary()) ? div(op.getSummary()).class_("redoc-op-summary") : null,
         nn(op.getDescription()) ? div(op.getDescription()).class_("redoc-op-desc") : null
      ).class_("redoc-op-block"));
   }

   private static final String DEFAULT_CSS =
      ".redoc-ui{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;color:#333;}" +
      ".redoc-container{display:flex;min-height:100vh;}" +
      ".redoc-sidebar{width:260px;background:#f4f5f7;padding:20px;border-right:1px solid #e1e4e8;overflow-y:auto;}" +
      ".redoc-content{flex:1;padding:30px 40px;background:#fff;}" +
      ".redoc-title{font-size:1.4em;font-weight:bold;margin-bottom:15px;color:#222;}" +
      ".redoc-toc{list-style:none;padding:0;margin:0 0 20px 0;}" +
      ".redoc-toc li{margin:6px 0;display:flex;align-items:center;}" +
      ".redoc-toc a{color:#0366d6;text-decoration:none;font-size:0.9em;margin-left:8px;}" +
      ".redoc-toc a:hover{text-decoration:underline;}" +
      ".redoc-section-title{font-weight:bold;margin-top:15px;color:#666;text-transform:uppercase;font-size:0.8em;}" +
      ".redoc-method{display:inline-block;font-size:0.7em;font-weight:bold;padding:2px 6px;border-radius:3px;color:#fff;text-transform:uppercase;}" +
      ".redoc-method-get{background:#61affe;}" +
      ".redoc-method-post{background:#49cc90;}" +
      ".redoc-method-put{background:#fca130;}" +
      ".redoc-method-delete{background:#f93e3e;}" +
      ".redoc-method-patch{background:#50e3c2;}" +
      ".redoc-method-head{background:#9012fe;}" +
      ".redoc-method-options{background:#0d5aa7;}" +
      ".redoc-method-trace{background:#ebebeb;color:#333;}" +
      ".redoc-op-block{border-bottom:1px solid #e1e4e8;padding:20px 0;}" +
      ".redoc-op-title{margin:0 0 10px 0;font-size:1.2em;}" +
      ".redoc-op-summary{font-weight:bold;margin-bottom:8px;}" +
      ".redoc-op-desc,.redoc-description,.redoc-model-desc{color:#555;line-height:1.5;}" +
      ".redoc-version{color:#666;font-size:0.9em;margin-bottom:15px;}";
}