Spreadsheet: Allow the user to format Identity cells via JS expressions

Also add some hints as to what the format field expects as it would be
very confusing otherwise.

Userland/Applications/Spreadsheet/CellType/Date.cpp

@@ -37,4 +37,11 @@ JS::ThrowCompletionOr<JS::Value> DateCell::js_value(Cell& cell, const CellTypeMe
     return JS::Value(value / 1000); // Turn it to seconds
 }
 
+String DateCell::metadata_hint(MetadataName metadata) const
+{
+    if (metadata == MetadataName::Format)
+        return "Date format string as supported by `strftime'";
+    return {};
+}
+
 }

Userland/Applications/Spreadsheet/CellType/Date.h

@@ -18,6 +18,7 @@ public:
     virtual ~DateCell() override = default;
     virtual JS::ThrowCompletionOr<String> display(Cell&, const CellTypeMetadata&) const override;
     virtual JS::ThrowCompletionOr<JS::Value> js_value(Cell&, const CellTypeMetadata&) const override;
+    String metadata_hint(MetadataName) const override;
 };
 
 }

Userland/Applications/Spreadsheet/CellType/Identity.cpp

@@ -15,9 +15,13 @@ IdentityCell::IdentityCell()
 {
 }
 
-JS::ThrowCompletionOr<String> IdentityCell::display(Cell& cell, const CellTypeMetadata&) const
+JS::ThrowCompletionOr<String> IdentityCell::display(Cell& cell, const CellTypeMetadata& metadata) const
 {
-    return cell.js_data().to_string(cell.sheet().global_object());
+    auto data = cell.js_data();
+    if (!metadata.format.is_empty())
+        data = TRY(cell.sheet().evaluate(metadata.format, &cell));
+
+    return data.to_string(cell.sheet().global_object());
 }
 
 JS::ThrowCompletionOr<JS::Value> IdentityCell::js_value(Cell& cell, const CellTypeMetadata&) const
@@ -25,4 +29,14 @@ JS::ThrowCompletionOr<JS::Value> IdentityCell::js_value(Cell& cell, const CellTy
     return cell.js_data();
 }
 
+String IdentityCell::metadata_hint(MetadataName metadata) const
+{
+    if (metadata == MetadataName::Length)
+        return "Ignored";
+    if (metadata == MetadataName::Format)
+        return "JavaScript expression, `value' refers to the cell's value";
+
+    return {};
+}
+
 }

Userland/Applications/Spreadsheet/CellType/Identity.h

@@ -17,6 +17,7 @@ public:
     virtual ~IdentityCell() override = default;
     virtual JS::ThrowCompletionOr<String> display(Cell&, const CellTypeMetadata&) const override;
     virtual JS::ThrowCompletionOr<JS::Value> js_value(Cell&, const CellTypeMetadata&) const override;
+    String metadata_hint(MetadataName) const override;
 };
 
 }

Userland/Applications/Spreadsheet/CellType/Numeric.cpp

@@ -41,4 +41,12 @@ JS::ThrowCompletionOr<JS::Value> NumericCell::js_value(Cell& cell, const CellTyp
     });
 }
 
+String NumericCell::metadata_hint(MetadataName metadata) const
+{
+    if (metadata == MetadataName::Format)
+        return "Format string as accepted by `printf', all numeric formats refer to the same value (the cell's value)";
+
+    return {};
+}
+
 }

Userland/Applications/Spreadsheet/CellType/Numeric.h

@@ -28,6 +28,7 @@ public:
     virtual ~NumericCell() override = default;
     virtual JS::ThrowCompletionOr<String> display(Cell&, const CellTypeMetadata&) const override;
     virtual JS::ThrowCompletionOr<JS::Value> js_value(Cell&, const CellTypeMetadata&) const override;
+    String metadata_hint(MetadataName) const override;
 };
 
 }

Userland/Applications/Spreadsheet/CellType/String.cpp

@@ -30,4 +30,11 @@ JS::ThrowCompletionOr<JS::Value> StringCell::js_value(Cell& cell, const CellType
     return JS::js_string(cell.sheet().interpreter().heap(), string);
 }
 
+String StringCell::metadata_hint(MetadataName metadata) const
+{
+    if (metadata == MetadataName::Format)
+        return "Ignored";
+    return {};
+}
+
 }

Userland/Applications/Spreadsheet/CellType/String.h

@@ -17,6 +17,7 @@ public:
     virtual ~StringCell() override = default;
     virtual JS::ThrowCompletionOr<String> display(Cell&, const CellTypeMetadata&) const override;
     virtual JS::ThrowCompletionOr<JS::Value> js_value(Cell&, const CellTypeMetadata&) const override;
+    String metadata_hint(MetadataName) const override;
 };
 
 }

Userland/Applications/Spreadsheet/CellType/Type.h

@@ -23,6 +23,13 @@ struct CellTypeMetadata {
     Format static_format;
 };
 
+enum class MetadataName {
+    Length,
+    Format,
+    Alignment,
+    StaticFormat,
+};
+
 class CellType {
 public:
     static const CellType* get_by_name(StringView);
@@ -30,6 +37,7 @@ public:
 
     virtual JS::ThrowCompletionOr<String> display(Cell&, const CellTypeMetadata&) const = 0;
     virtual JS::ThrowCompletionOr<JS::Value> js_value(Cell&, const CellTypeMetadata&) const = 0;
+    virtual String metadata_hint(MetadataName) const { return {}; }
     virtual ~CellType() = default;
 
     const String& name() const { return m_name; }

Userland/Applications/Spreadsheet/CellTypeDialog.cpp

@@ -153,6 +153,8 @@ void CellTypeDialog::setup_tabs(GUI::TabWidget& tabs, const Vector<Position>& po
             }
 
             m_type = CellType::get_by_name(g_types.at(index.row()));
+            if (auto* editor = right_side.find_descendant_of_type_named<GUI::TextEditor>("format_editor"))
+                editor->set_tooltip(m_type->metadata_hint(MetadataName::Format));
         };
 
         {
@@ -179,6 +181,7 @@ void CellTypeDialog::setup_tabs(GUI::TabWidget& tabs, const Vector<Position>& po
             auto& checkbox = right_side.add<GUI::CheckBox>("Override display format");
             auto& editor = right_side.add<GUI::TextEditor>();
             checkbox.set_checked(!m_format.is_empty());
+            editor.set_name("format_editor");
             editor.set_should_hide_unnecessary_scrollbars(true);
             editor.set_enabled(!m_format.is_empty());
             editor.set_text(m_format);