From a8bf9dd5b45f7dbd1fcc0f715faabdc4026a413b Mon Sep 17 00:00:00 2001
From: Emmanuel Engelhart <kelson@kiwix.org>
Date: Mon, 18 Jan 2021 11:18:53 +0100
Subject: [PATCH] Better Kiwix Serve Taskbar insertion (after charset
 definition)

---
 include/tools/regexTools.h |  3 +++
 src/server/response.cpp    |  4 ++--
 src/tools/regexTools.cpp   | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/tools/regexTools.h b/include/tools/regexTools.h
index ef7a3a52b..50ce28647 100644
--- a/include/tools/regexTools.h
+++ b/include/tools/regexTools.h
@@ -29,5 +29,8 @@ std::string replaceRegex(const std::string& content,
 std::string appendToFirstOccurence(const std::string& content,
                                    const std::string& regex,
                                    const std::string& replacement);
+std::string prependToFirstOccurence(const std::string& content,
+                                    const std::string& regex,
+                                    const std::string& replacement);
 
 #endif
diff --git a/src/server/response.cpp b/src/server/response.cpp
index fbb3728db..a25f107d9 100644
--- a/src/server/response.cpp
+++ b/src/server/response.cpp
@@ -203,9 +203,9 @@ void ContentResponse::introduce_taskbar()
   data.set("title", m_bookTitle);
   data.set("withlibrarybutton", m_withLibraryButton);
   auto head_content = render_template(RESOURCE::templates::head_part_html, data);
-  m_content = appendToFirstOccurence(
+  m_content = prependToFirstOccurence(
     m_content,
-    "<head[^>]*>",
+    "</head[^>]*>",
     head_content);
 
   auto taskbar_part = render_template(RESOURCE::templates::taskbar_part_html, data);
diff --git a/src/tools/regexTools.cpp b/src/tools/regexTools.cpp
index 1b70198f1..72fc29aa8 100644
--- a/src/tools/regexTools.cpp
+++ b/src/tools/regexTools.cpp
@@ -95,3 +95,22 @@ std::string appendToFirstOccurence(const std::string& content,
 
   return content;
 }
+
+std::string prependToFirstOccurence(const std::string& content,
+                                   const std::string& regex,
+                                   const std::string& replacement)
+{
+  ucnv_setDefaultName("UTF-8");
+  icu::UnicodeString ucontent(content.c_str());
+  icu::UnicodeString ureplacement(replacement.c_str());
+  auto matcher = buildMatcher(regex, ucontent);
+  if (matcher->find()) {
+    UErrorCode status = U_ZERO_ERROR;
+    ucontent.insert(matcher->start(status), ureplacement);
+    std::string tmp;
+    ucontent.toUTF8String(tmp);
+    return tmp;
+  }
+
+  return content;
+}