Spreadsheet: Add support for example views and hyperlinks in the docs

Now the functions can actually be demonstrated by small examples,
embedded right inside the documentation via:
spreadsheet://example/<page>#<example_name>

Also allows pages to link to each other via the same scheme:
spreadsheet://doc/<page>

Applications/Spreadsheet/HelpWindow.cpp

@@ -25,9 +25,12 @@
  */
 
 #include "HelpWindow.h"
+#include "SpreadsheetWidget.h"
+#include <AK/LexicalPath.h>
 #include <LibGUI/BoxLayout.h>
 #include <LibGUI/Frame.h>
 #include <LibGUI/ListView.h>
+#include <LibGUI/MessageBox.h>
 #include <LibGUI/Model.h>
 #include <LibGUI/Splitter.h>
 #include <LibMarkdown/Document.h>
@@ -97,18 +100,63 @@ HelpWindow::HelpWindow(GUI::Window* parent)
     m_listview->set_model(HelpListModel::create());
 
     m_webview = splitter.add<Web::OutOfProcessWebView>();
+    m_webview->on_link_click = [this](auto& url, auto&, auto&&) {
+        ASSERT(url.protocol() == "spreadsheet");
+        if (url.host() == "example") {
+            auto entry = LexicalPath(url.path()).basename();
+            auto doc_option = m_docs.get(entry);
+            if (!doc_option.is_object()) {
+                GUI::MessageBox::show_error(this, String::formatted("No documentation entry found for '{}'", url.path()));
+                return;
+            }
+            auto& doc = doc_option.as_object();
+            const auto& name = url.fragment();
+
+            auto example_data_value = doc.get_or("example_data", JsonObject {});
+            if (!example_data_value.is_object()) {
+                GUI::MessageBox::show_error(this, String::formatted("No example data found for '{}'", url.path()));
+                return;
+            }
+
+            auto& example_data = example_data_value.as_object();
+            auto value = example_data.get(name);
+            if (!value.is_object()) {
+                GUI::MessageBox::show_error(this, String::formatted("Example '{}' not found for '{}'", name, url.path()));
+                return;
+            }
+
+            auto dialog = GUI::Window::construct(this);
+            dialog->resize(size());
+            dialog->set_icon(icon());
+            dialog->set_title(String::formatted("Spreadsheet Help - Example {} for {}", name, entry));
+            auto& widget = dialog->set_main_widget<SpreadsheetWidget>(NonnullRefPtrVector<Sheet> {}, false);
+            auto sheet = Sheet::from_json(value.as_object(), widget.workbook());
+            if (!sheet) {
+                GUI::MessageBox::show_error(this, String::formatted("Corrupted example '{}' in '{}'", name, url.path()));
+                return;
+            }
+
+            widget.add_sheet(sheet.release_nonnull());
+            dialog->show();
+        } else if (url.host() == "doc") {
+            auto entry = LexicalPath(url.path()).basename();
+            m_webview->load(URL::create_with_data("text/html", render(entry)));
+        } else {
+            dbgln("Invalid spreadsheet action domain '{}'", url.host());
+        }
+    };
 
     m_listview->on_activation = [this](auto& index) {
         if (!m_webview)
             return;
 
-        m_webview->load(URL::create_with_data("text/html", render(index)));
+        auto key = static_cast<HelpListModel*>(m_listview->model())->key(index);
+        m_webview->load(URL::create_with_data("text/html", render(key)));
     };
 }
 
-String HelpWindow::render(const GUI::ModelIndex& index)
+String HelpWindow::render(const StringView& key)
 {
-    auto key = static_cast<HelpListModel*>(m_listview->model())->key(index);
     auto doc_option = m_docs.get(key);
     ASSERT(doc_option.is_object());
 
@@ -158,6 +206,7 @@ String HelpWindow::render(const GUI::ModelIndex& index)
     if (!examples.is_empty()) {
         markdown_builder.append("# EXAMPLES\n");
         examples.for_each_member([&](auto& text, auto& description_value) {
+            dbgln("- {}\n\n```js\n{}\n```\n", description_value.to_string(), text);
             markdown_builder.appendff("- {}\n\n```js\n{}\n```\n", description_value.to_string(), text);
         });
     }
@@ -176,5 +225,4 @@ void HelpWindow::set_docs(JsonObject&& docs)
 HelpWindow::~HelpWindow()
 {
 }
-
 }

Applications/Spreadsheet/HelpWindow.h

@@ -51,7 +51,7 @@ public:
 
 private:
     static RefPtr<HelpWindow> s_the;
-    String render(const GUI::ModelIndex&);
+    String render(const StringView& key);
     HelpWindow(GUI::Window* parent = nullptr);
 
     JsonObject m_docs;

Applications/Spreadsheet/Spreadsheet.h

@@ -100,6 +100,8 @@ public:
     Cell*& current_evaluated_cell() { return m_current_cell_being_evaluated; }
     bool has_been_visited(Cell* cell) const { return m_visited_cells_in_update.contains(cell); }
 
+    const Workbook& workbook() const { return m_workbook; }
+
 private:
     explicit Sheet(Workbook&);
     explicit Sheet(const StringView& name, Workbook&);

Applications/Spreadsheet/SpreadsheetWidget.cpp

@@ -186,10 +186,18 @@ void SpreadsheetWidget::add_sheet()
     name.append("Sheet");
     name.appendff(" {}", m_workbook->sheets().size() + 1);
 
-    auto& sheet = m_workbook->add_sheet(name.string_view());
+    NonnullRefPtrVector<Sheet> new_sheets;
+    new_sheets.append(m_workbook->add_sheet(name.string_view()));
+    setup_tabs(move(new_sheets));
+}
+
+void SpreadsheetWidget::add_sheet(NonnullRefPtr<Sheet>&& sheet)
+{
+    ASSERT(m_workbook == &sheet->workbook());
 
     NonnullRefPtrVector<Sheet> new_sheets;
-    new_sheets.append(sheet);
+    new_sheets.append(move(sheet));
+    m_workbook->sheets().append(new_sheets);
     setup_tabs(new_sheets);
 }
 

Applications/Spreadsheet/SpreadsheetWidget.h

@@ -42,11 +42,15 @@ public:
     void save(const StringView& filename);
     void load(const StringView& filename);
     void add_sheet();
+    void add_sheet(NonnullRefPtr<Sheet>&&);
 
     const String& current_filename() const { return m_workbook->current_filename(); }
     const Sheet& current_worksheet() const { return m_selected_view->sheet(); }
     void set_filename(const String& filename);
 
+    Workbook& workbook() { return *m_workbook; }
+    const Workbook& workbook() const { return *m_workbook; }
+
 private:
     explicit SpreadsheetWidget(NonnullRefPtrVector<Sheet>&& sheets = {}, bool should_add_sheet_if_empty = true);