/*
 * 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.console.freemarker;

import static org.apache.juneau.commons.utils.Shorts.*;

import java.io.*;
import java.util.*;

import org.apache.juneau.rest.server.view.freemarker.*;

import freemarker.core.*;
import freemarker.template.*;

/**
 * The {@code <@page>} shared FreeMarker directive: capture the nested body into {@link PageCapture}, resolve the
 * {@code toolkit=} packs, then include the consumer chrome template. A child {@code .ftlh} file <i>is</i> the page
 * call &mdash; it needs no leading include.
 *
 * <p>
 * {@code <@page>} is the outermost console directive; it must not be nested or repeated. The chrome template it
 * includes is expected to render exactly one {@code <@console>}, which in turn renders the page contract.
 *
 * @since 10.0.0
 */
public final class PageDirectiveModel implements TemplateDirectiveModel {

   /** The shared-variable name this directive registers under. */
   public static final String NAME = "page";

   static final Set<String> ATTRS = Set.of("tab", "init", "css", "toolkit");

   private final String chromeTemplate;
   private final ToolkitPackRegistry packs;

   PageDirectiveModel(String chromeTemplate, ToolkitPackRegistry packs) {
      this.chromeTemplate = chromeTemplate;
      this.packs = packs;
   }

   @Override
   @SuppressWarnings({
      "unchecked" // FreeMarker passes the directive params as a raw Map; it is assigned to Map<String,TemplateModel>, the type FreeMarker documents for them
   })
   public void execute(Environment env, @SuppressWarnings("rawtypes") Map params, TemplateModel[] loopVars,
         TemplateDirectiveBody body) throws TemplateException, IOException {
      Map<String, TemplateModel> p = params;
      if (p.containsKey("format"))
         throw FtlAttrLists.reject("<@page> has no format= attribute.");
      FtlAttrLists.rejectUnknown(p, NAME, ATTRS);
      if (n(body))
         throw FtlAttrLists.reject("<@page> requires a nested body.");

      var cap = PageCapture.of(env);
      if (cap.pageOpen || cap.consoleOpen || cap.consoleDone)
         throw FtlAttrLists.reject("<@page> must be the outermost console directive; it cannot be nested or repeated.");

      var toolkit = FtlAttrLists.list(p, NAME, "toolkit");
      try {
         packs.requireKnown(toolkit, "<@page toolkit=>");  // Fail fast on an unknown pack, before the body renders.
      } catch (IllegalArgumentException e) {
         throw FtlAttrLists.reject(e.getMessage());
      }
      cap.mergeTab(FtlAttrLists.scalar(p, "tab"));
      cap.mergeToolkit(toolkit);
      cap.mergeCss(FtlAttrLists.list(p, NAME, "css"));
      cap.mergeInit(FtlAttrLists.list(p, NAME, "init"));

      cap.pageOpen = true;
      try {
         body.render(cap.pageBuffer());
      } finally {
         cap.pageOpen = false;
      }
      cap.flushSegment();

      resolveAssets(env, cap, packs);

      env.include(env.getConfiguration().getTemplate(chromeTemplate));

      if (! cap.consoleDone)
         throw FtlAttrLists.reject(f(
            "<@page> chrome template '%s' rendered no <@console>; the legacy chrome was removed in 10.0.0.", chromeTemplate));
   }

   /**
    * Resolves the page's toolkit and card-required packs into the capture's script and link tags.
    *
    * <p>
    * Called after the page body (so the card requirements are known) against the merged toolkit list, so a pack named
    * only by a {@link PageSpec} still has its assets emitted.  Shared with {@code <@console>}, which runs it for a
    * page that never reached {@code <@page>} (a built page rendered straight through the chrome).
    *
    * <p>
    * On the built-page path the template name used in diagnostics is the chrome template, not the page template.
    */
   static void resolveAssets(Environment env, PageCapture cap, ToolkitPackRegistry packs) throws TemplateException {
      var roots = new java.util.ArrayList<>(cap.toolkits());
      roots.addAll(cap.requiredPacks());
      try {
         var pageUrls = new java.util.ArrayList<String>(cap.initScripts());
         pageUrls.addAll(cap.cssHrefs());
         cap.toolkitAssets(packs.resolve(roots, FreemarkerRenderScope.request(), pageUrls, env.getMainTemplate().getName()));
      } catch (IllegalArgumentException | IllegalStateException e) {
         throw FtlAttrLists.reject(e.getMessage());
      }
   }
}