Merge branch 'master' into jgrpp

# Conflicts:
#	cmake/SourceList.cmake
#	src/build_vehicle_gui.cpp
#	src/company_gui.cpp
#	src/console_cmds.cpp
#	src/depot_base.h
#	src/elrail.cpp
#	src/network/core/udp.cpp
#	src/network/network_admin.cpp
#	src/network/network_chat_gui.cpp
#	src/network/network_gui.cpp
#	src/network/network_server.cpp
#	src/newgrf.cpp
#	src/newgrf_engine.cpp
#	src/newgrf_railtype.cpp
#	src/newgrf_railtype.h
#	src/newgrf_storage.h
#	src/os/unix/crashlog_unix.cpp
#	src/rail.h
#	src/rail_cmd.cpp
#	src/rail_gui.cpp
#	src/road_cmd.cpp
#	src/road_map.h
#	src/saveload/labelmaps_sl.cpp
#	src/settings_gui.cpp
#	src/settings_type.h
#	src/sl/oldloader_sl.cpp
#	src/station_cmd.cpp
#	src/station_gui.cpp
#	src/table/settings/world_settings.ini
#	src/tests/test_script_admin.cpp
#	src/textfile_gui.cpp
#	src/toolbar_gui.cpp
#	src/train_cmd.cpp
#	src/tunnelbridge_cmd.cpp
#	src/vehicle_gui.cpp
#	src/widget.cpp
#	src/window.cpp
#	src/window_gui.h
#	src/window_type.h

src/textfile_gui.h

@@ -29,9 +29,6 @@ struct TextfileWindow : public Window, MissingGlyphSearcher {
 	TextfileType file_type;          ///< Type of textfile to view.
 	Scrollbar *vscroll;              ///< Vertical scrollbar.
 	Scrollbar *hscroll;              ///< Horizontal scrollbar.
-	uint search_iterator;            ///< Iterator for the font check search.
-
-	uint max_length;                 ///< Maximum length of unwrapped text line.
 
 	TextfileWindow(TextfileType file_type);
 
@@ -40,33 +37,86 @@ struct TextfileWindow : public Window, MissingGlyphSearcher {
 	void DrawWidget(const Rect &r, int widget) const override;
 	void OnResize() override;
 	void OnInvalidateData(int data = 0, bool gui_scope = true) override;
+	void OnDropdownSelect(int widget, int index) override;
 
 	void Reset() override;
 	FontSize DefaultSize() override;
 	std::optional<std::string_view> NextString() override;
 	bool Monospace() override;
 	void SetFontNames(FontCacheSettings *settings, const char *font_name, const void *os_data) override;
+	void ScrollToLine(size_t line);
 
 	virtual void LoadTextfile(const char *textfile, Subdirectory dir);
 
-protected:
-	void LoadText(std::string_view buf);
+	inline void LoadTextfile(const std::string &textfile, Subdirectory dir)
+	{
+		this->LoadTextfile(textfile.c_str(), dir);
+	}
 
-private:
+protected:
 	struct Line {
-		int top;               ///< Top scroll position.
-		int bottom;            ///< Bottom scroll position.
-		std::string_view text; ///< Pointer to text buffer.
+		int top{0};                  ///< Top scroll position in visual lines.
+		int bottom{0};               ///< Bottom scroll position in visual lines.
+		std::string text{};          ///< Contents of the line.
+		TextColour colour{TC_WHITE}; ///< Colour to render text line in.
 
 		Line(int top, std::string_view text) : top(top), bottom(top + 1), text(text) {}
+		Line() {}
 	};
 
-	std::string text;                ///< Lines of text from the NewGRF's textfile.
-	std::vector<Line> lines;         ///< #text, split into lines in a table with lines.
+	struct Hyperlink {
+		size_t line;             ///< Which line the link is on.
+		size_t begin;            ///< Character position on line the link begins.
+		size_t end;              ///< Character position on line the link end.
+		std::string destination; ///< Destination for the link.
+	};
+
+	struct HistoryEntry {
+		std::string filepath;    ///< File the history entry is in.
+		int scrollpos;           ///< Scrolling position the file was at at navigation time.
+	};
+
+	std::string filename{};              ///< Filename of the textfile.
+	std::string filepath{};              ///< Full path to the filename.
+
+	std::vector<Line> lines;             ///< #text, split into lines in a table with lines.
+	std::vector<size_t> jumplist;        ///< Table of contents list, line numbers.
+	std::vector<Hyperlink> links;        ///< Clickable links in lines.
+	std::vector<Hyperlink> link_anchors; ///< Anchor names of headings that can be linked to.
+	std::vector<HistoryEntry> history;   ///< Browsing history in this window.
+	size_t history_pos{0};               ///< Position in browsing history (for forward movement).
+	bool trusted{false};                 ///< Whether the content is trusted (read: not from content like NewGRFs, etc).
+
+	void LoadText(std::string_view buf);
+	void FindHyperlinksInMarkdown(Line &line, size_t line_index);
+
+	/**
+	 * Handle the clicking on a hyperlink.
+	 *
+	 * @param link The link that is clicked on.
+	 */
+	virtual void OnHyperlinkClick(const Hyperlink &link);
+
+	/**
+	 * Post-processing after the text is loaded.
+	 */
+	virtual void AfterLoadText();
+
+	void NavigateToFile(std::string newfile, size_t line);
+	void AppendHistory(const std::string &filepath);
+	void UpdateHistoryScrollpos();
+	void NavigateHistory(int delta);
+
+private:
+	uint search_iterator{0};     ///< Iterator for the font check search.
+	uint max_length{0};          ///< Maximum length of unwrapped text line.
 
 	uint ReflowContent();
 	uint GetContentHeight();
 	void SetupScrollbars(bool force_reflow);
+	void CheckHyperlinkClick(Point pt);
+
+	void AfterLoadMarkdown();
 };
 
 #endif /* TEXTFILE_GUI_H */