//! Saved Scenario navigation is presentation state, never a document edit.
use super::*;
use crate::behavior::scenario_layout::{Representation, presentation::checked_owner};

impl App {
    pub(super) fn enter_scenario_representation(&mut self, representation: Representation) -> bool {
        let Some(owner) = checked_owner(self.project(), representation) else {
            self.status =
                "This Scenario view is no longer available or has an incompatible owner.".into();
            return false;
        };
        self.layer = self.project().elements[&owner].layer();
        self.page = Page::Behavior;
        self.behavior.active_owner = Some(owner);
        match representation {
            Representation::Saved { diagram } => self.active_diagram = Some(diagram),
            Representation::Derived { .. } => {
                if self
                    .active_diagram
                    .is_some_and(|id| self.saved_scenario_diagram(id))
                {
                    self.active_diagram = None;
                }
            }
        }
        self.selected_node = None;
        if self
            .behavior
            .scenario
            .enter_representation(self.canvas_document, owner, representation)
        {
            self.canvas_epoch = self.canvas_epoch.wrapping_add(1);
        }
        true
    }

    /// Reconcile after navigation/adoption without selecting or applying a draft.
    /// A retained invalid Saved identity remains unavailable; it must not silently
    /// turn into a different automatic Scenario or another saved arrangement.
    pub(super) fn reconcile_scenario_workspace(&mut self) {
        if self.page == Page::Diagram
            && !self.behavior.has_pending()
            && let Some(diagram) = self
                .active_diagram
                .filter(|id| self.saved_scenario_diagram(*id))
        {
            self.enter_scenario_representation(Representation::Saved { diagram });
        }
        if self.page != Page::Behavior {
            self.behavior.scenario.leave();
            return;
        }
        if let Some(rep @ Representation::Saved { diagram }) =
            self.behavior.scenario.representation()
        {
            // The requested view is authoritative until explicit navigation
            // retires it. This also recovers the same view when Undo restores it.
            if let Some(owner) = checked_owner(self.project(), rep) {
                self.active_diagram = Some(diagram);
                self.layer = self.project().elements[&owner].layer();
                self.behavior.active_owner = Some(owner);
                self.behavior
                    .scenario
                    .enter_representation(self.canvas_document, owner, rep);
            } else if let Some(owner) = self.behavior.scenario.owner() {
                self.behavior
                    .scenario
                    .enter_representation(self.canvas_document, owner, rep);
            }
            return;
        }
        let Some(owner) = behavior::selected_owner(self) else {
            self.behavior.scenario.leave();
            return;
        };
        if self
            .project()
            .elements
            .get(&owner)
            .is_some_and(|e| e.kind() == Kind::Scenario)
        {
            self.behavior.scenario.enter(self.canvas_document, owner);
        } else {
            self.behavior.scenario.leave();
        }
    }
}

#[cfg(test)]
mod tests;

#[cfg(test)]
mod adoption_tests;

#[cfg(test)]
mod owner_navigation_tests;