// Copyright (C) 2009 The Android Open Source Project
//
// 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 com.urswolfer.intellij.plugin.gerrit.util.safehtml;

// based on: https://gerrit.googlesource.com/gerrit/+/master/gerrit-gwtexpui/src/main/java/com/google/gwtexpui/safehtml/client/

/** Immutable string safely placed as HTML without further escaping. */
@SuppressWarnings("serial")
public abstract class SafeHtml {

  /** @return the existing HTML text, wrapped in a safe buffer. */
  public static SafeHtml asis(String htmlText) {
    return new SafeHtmlString(htmlText);
  }

  /** Convert bare http:// and https:// URLs into &lt;a href&gt; tags. */
  public SafeHtml linkify() {
    final String part = "(?:[a-zA-Z0-9$_+!*'%;:@=?#/~-]|&(?!lt;|gt;)|[.,](?!(?:\\s|$)))";
    return replaceAll(
        "(https?://" + part + "{2,}(?:[(]" + part + "*[)])*" + part + "*)",
        "<a href=\"$1\" target=\"_blank\" rel=\"nofollow\">$1</a>");
  }

  /**
   * Apply {@link #linkify()}, and "\n\n" to &lt;p&gt;.
   *
   * <p>Lines that start with whitespace are assumed to be preformatted.
   */
  public SafeHtml wikify() {
    final SafeHtmlBuilder r = new SafeHtmlBuilder();
    for (String p : linkify().asString().split("\n\n")) {
      if (isQuote(p)) {
        wikifyQuote(r, p);

      } else if (isPreFormat(p)) {
        r.openElement("p");
        for (String line : p.split("\n")) {
          r.openSpan();
          r.append(asis(line));
          r.closeSpan();
          r.br();
        }
        r.closeElement("p");

      } else if (isList(p)) {
        wikifyList(r, p);

      } else {
        r.openElement("p");
        r.append(asis(p));
        r.closeElement("p");
      }
    }
    return r.toSafeHtml();
  }

  private void wikifyList(SafeHtmlBuilder r, String p) {
    boolean in_ul = false;
    boolean in_p = false;
    for (String line : p.split("\n")) {
      if (line.startsWith("-") || line.startsWith("*")) {
        if (!in_ul) {
          if (in_p) {
            in_p = false;
            r.closeElement("p");
          }

          in_ul = true;
          r.openElement("ul");
        }
        line = line.substring(1).trim();

      } else if (!in_ul) {
        if (!in_p) {
          in_p = true;
          r.openElement("p");
        } else {
          r.append(' ');
        }
        r.append(asis(line));
        continue;
      }

      r.openElement("li");
      r.append(asis(line));
      r.closeElement("li");
    }

    if (in_ul) {
      r.closeElement("ul");
    } else if (in_p) {
      r.closeElement("p");
    }
  }

  private void wikifyQuote(SafeHtmlBuilder r, String p) {
    r.openElement("blockquote");
    if (p.startsWith("&gt; ")) {
      p = p.substring(5);
    } else if (p.startsWith(" &gt; ")) {
      p = p.substring(6);
    }
    p = p.replaceAll("\\n ?&gt; ", "\n");
    for (String e : p.split("\n\n")) {
      if (isQuote(e)) {
        SafeHtmlBuilder b = new SafeHtmlBuilder();
        wikifyQuote(b, e);
        r.append(b);
      } else {
        r.append(asis(e));
      }
    }
    r.closeElement("blockquote");
  }

  private static boolean isQuote(String p) {
    return p.startsWith("&gt; ") || p.startsWith(" &gt; ");
  }

  private static boolean isPreFormat(String p) {
    return p.contains("\n ") || p.contains("\n\t") || p.startsWith(" ") || p.startsWith("\t");
  }

  private static boolean isList(String p) {
    return p.contains("\n- ") || p.contains("\n* ") || p.startsWith("- ") || p.startsWith("* ");
  }

  /**
   * Replace first occurrence of {@code regex} with {@code repl} .
   *
   * <p><b>WARNING:</b> This replacement is being performed against an otherwise safe HTML string.
   * The caller must ensure that the replacement does not introduce cross-site scripting attack
   * entry points.
   *
   * @param regex regular expression pattern to match the substring with.
   * @param repl replacement expression. Capture groups within {@code regex} can be referenced with
   *     {@code $<i>n</i>}.
   * @return a new string, after the replacement has been made.
   */
  public SafeHtml replaceFirst(String regex, String repl) {
    return new SafeHtmlString(asString().replaceFirst(regex, repl));
  }

  /**
   * Replace each occurrence of {@code regex} with {@code repl} .
   *
   * <p><b>WARNING:</b> This replacement is being performed against an otherwise safe HTML string.
   * The caller must ensure that the replacement does not introduce cross-site scripting attack
   * entry points.
   *
   * @param regex regular expression pattern to match substrings with.
   * @param repl replacement expression. Capture groups within {@code regex} can be referenced with
   *     {@code $<i>n</i>}.
   * @return a new string, after the replacements have been made.
   */
  public SafeHtml replaceAll(String regex, String repl) {
    return new SafeHtmlString(asString().replaceAll(regex, repl));
  }

  /** @return a clean HTML string safe for inclusion in any context. */
  public abstract String asString();
}

@@ -1844,36 +1844,38 @@
 r.openElement(%22p
+re
 %22);%0A
-
         for (Str
@@ -1906,32 +1906,8 @@
 ) %7B%0A
-          r.openSpan();%0A
     
@@ -1938,33 +1938,8 @@
 ));%0A
-          r.closeSpan();%0A
     
@@ -1954,32 +1954,32 @@
 br();%0A        %7D%0A
-
         r.closeE
@@ -1983,24 +1983,26 @@
 seElement(%22p
+re
 %22);%0A%0A      %7D

fix pre-formatted blocks after sync of 'safehtml'