Allow selecting options by line ID

Author: exoego

crates/bevy_plugin/assets/options.yarn

@@ -11,11 +11,11 @@ Ancient Reptilian Brain: Never ever.
 title: Hub0
 position: -43,-216
 ---
--> You: Never ever ever? <<if $never == false>>
+-> You: Never ever ever? <<if $never == false>> #line:x1
     Ancient Reptilian Brain: Never ever ever ever, baby!
     <<set $never to true>>
     <<jump Hub0>>
--> You: (Simply keep on non-existing.)
+-> You: (Simply keep on non-existing.) #line:x2
     Ancient Reptilian Brain: An inordinate amount of time passes. It is utterly void of struggle. No ex-wives are contained within it.
 
 <<set $great to false>>

crates/bevy_plugin/src/dialogue_runner.rs

@@ -102,6 +102,25 @@ impl DialogueRunner {
         Ok(self)
     }
 
+    /// If the dialogue is currently waiting for the user to select an option, this method will select the option with the given id.
+    /// Implies [`DialogueRunner::continue_in_next_update`].
+    pub fn select_option_by_line_id(&mut self, line: LineId) -> Result<&mut Self> {
+        if !self.is_running {
+            bail!(
+                "Can't select option of line id {line}: the dialogue is currently not running. Please call `DialogueRunner::continue_in_next_update()` only after receiving a `PresentOptionsEvent`."
+            )
+        }
+
+        let option = self
+            .inner_mut()
+            .0
+            .set_selected_option_by_line_id(line)
+            .map_err(Error::from)?;
+        self.last_selected_option.replace(option);
+        self.continue_in_next_update();
+        Ok(self)
+    }
+
     /// Returns whether the dialogue runner is currently running. Returns `false` if:
     /// - The dialogue has not yet been started via [`DialogueRunner::start_node`]
     /// - The dialogue has been stopped via [`DialogueRunner::stop`]

crates/bevy_plugin/tests/test_dialogue_runner_delivers_options.rs

@@ -57,6 +57,18 @@ fn errs_on_unexpected_selection_value() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn errs_on_unexpected_line_id() -> Result<()> {
+    let mut app = App::new();
+    app.setup_dialogue_runner().start_node("Start");
+    app.continue_dialogue_and_update_n_times(4);
+    app.dialogue_runner_mut()
+        .select_option_by_line_id(LineId("line:1".to_string()))
+        .unwrap_err();
+
+    Ok(())
+}
+
 #[test]
 fn option_selection_implies_continue() -> Result<()> {
     let mut app = App::new();
@@ -158,6 +170,35 @@ fn can_select_unavailable_choice() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn can_select_by_line_id() -> Result<()> {
+    let mut app = App::new();
+    let mut asserter = EventAsserter::new();
+    app.setup_dialogue_runner().start_node("Start");
+    app.continue_dialogue_and_update_n_times(4);
+    app.dialogue_runner_mut()
+        .select_option_by_line_id(LineId("line:x1".to_string()))?;
+    app.continue_dialogue_and_update();
+    asserter.clear_events(&mut app);
+
+    app.continue_dialogue_and_update();
+    assert_events!(asserter, app contains [
+        PresentLineEvent (n = 0),
+        PresentOptionsEvent with |event|
+            event.options.len() == 2
+            && event.options.iter().filter(|o| o.is_available).count() == 1
+            && event.options.iter().filter(|o| !o.is_available).all(|o| o.id == OptionId(0)),
+    ]);
+    app.dialogue_runner_mut().select_option(OptionId(0))?;
+    app.update();
+    assert_events!(asserter, app contains [
+        PresentLineEvent with |event| event.line.text == lines()[6],
+        PresentOptionsEvent (n = 0),
+    ]);
+
+    Ok(())
+}
+
 #[test]
 fn generates_files_in_dev_mode() -> Result<()> {
     let dir = tempdir()?;

crates/runtime/src/dialogue.rs

@@ -34,6 +34,10 @@ pub enum DialogueError {
         selected_option_id: OptionId,
         max_id: usize,
     },
+    InvalidLineIdError {
+        selected_line_id: LineId,
+        line_ids: Vec<LineId>,
+    },
     UnexpectedOptionSelectionError,
     ContinueOnOptionSelectionError,
     NoNodeSelectedOnContinue,
@@ -66,6 +70,10 @@ impl Display for DialogueError {
             MarkupParseError(e) => Display::fmt(e, f),
             LineProviderError { id, language_code } => write!(f, "Line ID \"{id}\" not found in line provider with language code {language_code:?}"),
             InvalidOptionIdError { selected_option_id, max_id } => write!(f, "{selected_option_id:?} is not a valid option ID (expected a number between 0 and {max_id}."),
+            InvalidLineIdError { selected_line_id, line_ids } => {
+                let line_ids = line_ids.iter().map(|id| id.0.clone()).collect::<Vec<_>>().join(", ");
+                write!(f, "{selected_line_id:?} is not a valid line ID of options (expected line ids: {line_ids}.")
+            },
             UnexpectedOptionSelectionError => f.write_str("An option was selected, but the dialogue wasn't waiting for a selection. This method should only be called after the Dialogue is waiting for the user to select an option."),
             ContinueOnOptionSelectionError => f.write_str("Dialogue was asked to continue running, but it is waiting for the user to select an option first."),
             NoNodeSelectedOnContinue => f.write_str("Cannot continue running dialogue. No node has been selected."),
@@ -475,6 +483,23 @@ impl Dialogue {
         Ok(self)
     }
 
+    /// Signals to the [`Dialogue`] that the user has selected a specified [`DialogueOption`].
+    ///
+    /// This makes dialogue replay more robust than [`self.set_selected_option`] when adding new options.
+    ///
+    /// The ID number that should be passed as the parameter to this method should be the id
+    /// of the [`line`] field in the [`DialogueOption`] that represents the user's selection.
+    ///
+    /// ## Panics
+    /// - If the Dialogue is not expecting an option to be selected.
+    /// - If the line ID is not found in the vector of [`DialogueOption`] provided by [`DialogueEvent::Options`].
+    ///
+    /// ## See Also
+    /// - [`Dialogue::continue_`]
+    pub fn set_selected_option_by_line_id(&mut self, selected_line_id: LineId) -> Result<OptionId> {
+        self.vm.set_selected_option_by_line_id(selected_line_id)
+    }
+
     /// Gets a value indicating whether the Dialogue is currently executing Yarn instructions.
     #[must_use]
     pub fn is_active(&self) -> bool {

crates/runtime/src/virtual_machine.rs

@@ -254,6 +254,36 @@ impl VirtualMachine {
         Ok(())
     }
 
+    pub(crate) fn set_selected_option_by_line_id(
+        &mut self,
+        selected_line_id: LineId,
+    ) -> Result<OptionId> {
+        if self.execution_state != ExecutionState::WaitingOnOptionSelection {
+            return Err(DialogueError::UnexpectedOptionSelectionError);
+        }
+        if let Some(selected_option) = self
+            .state
+            .current_options
+            .iter()
+            .find(|o| o.line.id == selected_line_id)
+        {
+            let selected_option_id = selected_option.id.clone();
+            self.set_selected_option(selected_option_id)
+                .map(|_| selected_option_id)
+        } else {
+            let line_ids = self
+                .state
+                .current_options
+                .iter()
+                .map(|o| o.line.id.clone())
+                .collect();
+            Err(DialogueError::InvalidLineIdError {
+                selected_line_id,
+                line_ids,
+            })
+        }
+    }
+
     pub(crate) fn is_active(&self) -> bool {
         self.execution_state != ExecutionState::Stopped
     }