lingxia_shell/

runtime.rs

use crate::{
    ResolvedShellSidebarAction, ShellError, ShellManager, ShellPin, ShellPinTarget, ShellResult,
    ShellSidebarAction,
};
use std::path::PathBuf;
use std::sync::{Arc, Mutex, OnceLock};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct SidebarActionIntent {
    pub id: String,
    pub generation: u64,
}

pub trait ShellHost: Send + Sync + 'static {
    fn resolve_sidebar_actions(
        &self,
        generation: u64,
        items: &[ShellSidebarAction],
    ) -> ShellResult<Vec<ResolvedShellSidebarAction>>;

    fn apply_sidebar_actions(&self, items: &[ResolvedShellSidebarAction]) -> ShellResult<()>;

    fn apply_pins(&self, items: &[ShellPin]) -> ShellResult<()>;

    fn activate(&self, intent: SidebarActionIntent) -> ShellResult<()>;
}

#[derive(Clone)]
struct ActiveShell {
    manager: Arc<ShellManager>,
    host: Arc<dyn ShellHost>,
}

fn active_slot() -> &'static Mutex<Option<ActiveShell>> {
    static ACTIVE: OnceLock<Mutex<Option<ActiveShell>>> = OnceLock::new();
    ACTIVE.get_or_init(|| Mutex::new(None))
}

pub fn initialize(root: impl Into<PathBuf>, host: Arc<dyn ShellHost>) -> ShellResult<()> {
    let manager = Arc::new(ShellManager::open(root)?);
    let mut active = active_slot()
        .lock()
        .map_err(|_| ShellError::Host("active shell state is poisoned".to_string()))?;
    *active = Some(ActiveShell { manager, host });
    Ok(())
}

pub fn manager() -> ShellResult<Arc<ShellManager>> {
    active_slot()
        .lock()
        .map_err(|_| ShellError::Host("active shell state is poisoned".to_string()))?
        .as_ref()
        .map(|active| active.manager.clone())
        .ok_or(ShellError::NotInitialized)
}

pub fn resolved_sidebar_actions() -> ShellResult<Vec<ResolvedShellSidebarAction>> {
    with_active(|active| {
        let snapshot = active.manager.snapshot();
        active.host.resolve_sidebar_actions(
            snapshot.sidebar_actions.generation(),
            snapshot.sidebar_actions.items(),
        )
    })
}

pub fn apply_current_sidebar_actions() -> ShellResult<Vec<ResolvedShellSidebarAction>> {
    with_active(|active| {
        let snapshot = active.manager.snapshot();
        let resolved = active.host.resolve_sidebar_actions(
            snapshot.sidebar_actions.generation(),
            snapshot.sidebar_actions.items(),
        )?;
        active.host.apply_sidebar_actions(&resolved)?;
        Ok(resolved)
    })
}

/// The sidebar state the user last settled on, or the expanded default when
/// the shell is not initialized.
pub fn sidebar_chrome() -> crate::SidebarChrome {
    manager()
        .map(|manager| manager.sidebar_chrome())
        .unwrap_or_default()
}

/// Record the user's own sidebar choice. Never call this for the adaptive
/// projection: a narrow window forcing a rail is not a choice, and writing it
/// down would make the next launch open as a rail on any window size.
pub fn set_sidebar_chrome(chrome: crate::SidebarChrome) -> ShellResult<()> {
    manager()?.set_sidebar_chrome(chrome)
}

pub fn window_frame() -> Option<crate::WindowFrame> {
    manager().ok().and_then(|manager| manager.window_frame())
}

pub fn set_window_frame(frame: crate::WindowFrame) -> ShellResult<()> {
    manager()?.set_window_frame(frame)
}

pub fn pins() -> ShellResult<Vec<ShellPin>> {
    Ok(manager()?.snapshot().pins.items)
}

pub fn apply_current_pins() -> ShellResult<Vec<ShellPin>> {
    with_active(|active| {
        let items = active.manager.snapshot().pins.items;
        active.host.apply_pins(&items)?;
        Ok(items)
    })
}

pub fn is_pinned(target: &ShellPinTarget) -> ShellResult<bool> {
    Ok(manager()?.snapshot().pins.is_pinned(target))
}

pub fn set_pinned(target: ShellPinTarget, pinned: bool) -> ShellResult<crate::PinMutation> {
    let _mutation = pin_mutation_lock()
        .lock()
        .map_err(|_| ShellError::Host("shell Pin mutation state is poisoned".to_string()))?;
    with_active(|active| {
        let previous = active.manager.snapshot().pins;
        let (mutation, snapshot) = if pinned {
            active.manager.pin(target)?
        } else {
            active.manager.unpin(&target)?
        };
        if mutation == crate::PinMutation::Changed
            && let Err(error) = active.host.apply_pins(&snapshot.pins.items)
        {
            let _ = active.manager.commit_pins(&snapshot.pins, previous.clone());
            let _ = active.host.apply_pins(&previous.items);
            return Err(error);
        }
        Ok(mutation)
    })
}

pub fn reorder_pins(items: Vec<ShellPin>) -> ShellResult<crate::PinMutation> {
    let _mutation = pin_mutation_lock()
        .lock()
        .map_err(|_| ShellError::Host("shell Pin mutation state is poisoned".to_string()))?;
    with_active(|active| {
        let previous = active.manager.snapshot().pins;
        let mut next = previous.clone();
        let mutation = next.reorder(items)?;
        if mutation == crate::PinMutation::Unchanged {
            return Ok(mutation);
        }
        let snapshot = active.manager.commit_pins(&previous, next)?;
        if let Err(error) = active.host.apply_pins(&snapshot.pins.items) {
            active
                .manager
                .commit_pins(&snapshot.pins, previous.clone())?;
            let _ = active.host.apply_pins(&previous.items);
            return Err(error);
        }
        Ok(mutation)
    })
}

fn pin_mutation_lock() -> &'static Mutex<()> {
    static MUTATION: OnceLock<Mutex<()>> = OnceLock::new();
    MUTATION.get_or_init(|| Mutex::new(()))
}

pub fn activate_sidebar_action(mut intent: SidebarActionIntent) -> ShellResult<()> {
    let id = intent.id.trim().to_string();
    if id.is_empty() {
        return Err(ShellError::EmptySidebarActionId);
    }
    intent.id = id.clone();
    with_active(|active| {
        let snapshot = active.manager.snapshot();
        let current_generation = snapshot.sidebar_actions.generation();
        if intent.generation != current_generation {
            // Chrome can be one replace() behind: the same stable id is still
            // live, so retarget rather than drop the click. A recycled or
            // cleared id still fails.
            let still_live = snapshot
                .sidebar_actions
                .items()
                .iter()
                .any(|item| item.id == id);
            if still_live {
                intent.generation = current_generation;
            } else {
                return Err(ShellError::StaleSidebarActionIntent {
                    generation: intent.generation,
                    current: current_generation,
                });
            }
        }
        let Some(item) = snapshot
            .sidebar_actions
            .items()
            .iter()
            .find(|item| item.id == id)
        else {
            return Err(ShellError::SidebarActionNotFound { id: id.to_string() });
        };
        if item.disabled {
            return Err(ShellError::SidebarActionDisabled { id: id.to_string() });
        }
        active.host.activate(intent)
    })
}

fn with_active<T>(run: impl FnOnce(&ActiveShell) -> ShellResult<T>) -> ShellResult<T> {
    let active = {
        let slot = active_slot()
            .lock()
            .map_err(|_| ShellError::Host("active shell state is poisoned".to_string()))?;
        slot.clone().ok_or(ShellError::NotInitialized)?
    };
    run(&active)
}

#[cfg(test)]
pub(crate) fn reset_for_test() {
    *active_slot().lock().unwrap() = None;
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::sync::atomic::{AtomicBool, Ordering};

    fn test_guard() -> std::sync::MutexGuard<'static, ()> {
        static TEST_LOCK: Mutex<()> = Mutex::new(());
        TEST_LOCK.lock().unwrap_or_else(|error| error.into_inner())
    }

    #[derive(Default)]
    struct TestHost {
        activated: Mutex<Vec<SidebarActionIntent>>,
        applied: Mutex<Vec<Vec<ResolvedShellSidebarAction>>>,
        applied_pins: Mutex<Vec<Vec<ShellPin>>>,
        reject_pins: AtomicBool,
    }

    impl ShellHost for TestHost {
        fn resolve_sidebar_actions(
            &self,
            generation: u64,
            items: &[ShellSidebarAction],
        ) -> ShellResult<Vec<ResolvedShellSidebarAction>> {
            Ok(items
                .iter()
                .map(|item| ResolvedShellSidebarAction {
                    generation,
                    id: item.id.clone(),
                    placement: item.placement,
                    label: item.label.clone(),
                    icon_path: Some(item.icon.clone()),
                    disabled: item.disabled,
                })
                .collect())
        }

        fn apply_sidebar_actions(&self, items: &[ResolvedShellSidebarAction]) -> ShellResult<()> {
            self.applied.lock().unwrap().push(items.to_vec());
            Ok(())
        }

        fn apply_pins(&self, items: &[ShellPin]) -> ShellResult<()> {
            self.applied_pins.lock().unwrap().push(items.to_vec());
            if self.reject_pins.load(Ordering::Relaxed) {
                return Err(ShellError::Host("rejected Pins".to_string()));
            }
            Ok(())
        }

        fn activate(&self, intent: SidebarActionIntent) -> ShellResult<()> {
            self.activated.lock().unwrap().push(intent);
            Ok(())
        }
    }

    #[test]
    fn stable_id_activation_routes_the_current_generation() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        manager()
            .unwrap()
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "sync".to_string(),
                placement: crate::SidebarActionPlacement::Footer,
                label: "Sync".to_string(),
                icon: "icons/sync.svg".to_string(),
                disabled: false,
            }])
            .unwrap();

        activate_sidebar_action(SidebarActionIntent {
            id: "sync".to_string(),
            generation: 1,
        })
        .unwrap();

        assert_eq!(
            host.activated.lock().unwrap().as_slice(),
            &[SidebarActionIntent {
                id: "sync".to_string(),
                generation: 1,
            }]
        );
        assert!(host.applied.lock().unwrap().is_empty());
    }

    #[test]
    fn settings_shaped_runtime_action_stays_on_the_generic_host_channel() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        manager()
            .unwrap()
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "settings".to_string(),
                placement: crate::SidebarActionPlacement::Footer,
                label: "Settings".to_string(),
                icon: "settings".to_string(),
                disabled: false,
            }])
            .unwrap();

        activate_sidebar_action(SidebarActionIntent {
            id: "settings".to_string(),
            generation: 1,
        })
        .unwrap();

        assert_eq!(
            host.activated.lock().unwrap().as_slice(),
            &[SidebarActionIntent {
                id: "settings".to_string(),
                generation: 1,
            }]
        );
    }

    #[test]
    fn disabled_items_never_reach_the_host() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        manager()
            .unwrap()
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "chat".to_string(),
                placement: crate::SidebarActionPlacement::Footer,
                label: "Chat".to_string(),
                icon: "icons/chat.svg".to_string(),
                disabled: true,
            }])
            .unwrap();

        assert_eq!(
            activate_sidebar_action(SidebarActionIntent {
                id: "chat".to_string(),
                generation: 1,
            }),
            Err(ShellError::SidebarActionDisabled {
                id: "chat".to_string()
            })
        );
        assert!(host.activated.lock().unwrap().is_empty());
    }

    #[test]
    fn stale_generation_retargets_when_the_id_is_still_live() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        let manager = manager().unwrap();
        manager
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "brand".to_string(),
                placement: crate::SidebarActionPlacement::Footer,
                label: "Brand".to_string(),
                icon: "icons/brand.svg".to_string(),
                disabled: false,
            }])
            .unwrap();
        manager
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "brand".to_string(),
                placement: crate::SidebarActionPlacement::Footer,
                label: "Brand 2".to_string(),
                icon: "icons/brand.svg".to_string(),
                disabled: false,
            }])
            .unwrap();

        activate_sidebar_action(SidebarActionIntent {
            id: "brand".to_string(),
            generation: 1,
        })
        .unwrap();

        assert_eq!(
            host.activated.lock().unwrap().as_slice(),
            &[SidebarActionIntent {
                id: "brand".to_string(),
                generation: 2,
            }]
        );
    }

    #[test]
    fn stale_generation_never_retargets_a_replaced_action() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        let manager = manager().unwrap();
        manager
            .replace_sidebar_actions(vec![ShellSidebarAction {
                id: "settings".to_string(),
                placement: crate::SidebarActionPlacement::Header,
                label: "Settings".to_string(),
                icon: "icons/settings.svg".to_string(),
                disabled: false,
            }])
            .unwrap();
        manager.clear_sidebar_actions().unwrap();

        assert_eq!(
            activate_sidebar_action(SidebarActionIntent {
                id: "settings".to_string(),
                generation: 1,
            }),
            Err(ShellError::StaleSidebarActionIntent {
                generation: 1,
                current: 2,
            })
        );
        assert!(host.activated.lock().unwrap().is_empty());
    }

    #[test]
    fn pin_mutations_apply_one_mixed_order_and_reject_ninth() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        for index in 0..crate::MAX_SHELL_PINS {
            let target = if index % 2 == 0 {
                ShellPinTarget::Lxapp {
                    key: format!("app.{index}"),
                }
            } else {
                ShellPinTarget::Bookmark {
                    key: format!("bookmark-{index}"),
                }
            };
            set_pinned(target, true).unwrap();
        }

        assert_eq!(host.applied_pins.lock().unwrap().len(), 8);
        assert_eq!(
            set_pinned(
                ShellPinTarget::Lxapp {
                    key: "app.overflow".to_string(),
                },
                true,
            ),
            Err(ShellError::LimitReached {
                max: crate::MAX_SHELL_PINS,
            })
        );
        assert_eq!(host.applied_pins.lock().unwrap().len(), 8);
    }

    #[test]
    fn reorder_persists_mixed_order_and_rolls_back_rejected_projection() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        set_pinned(ShellPinTarget::Lxapp { key: "chat".into() }, true).unwrap();
        set_pinned(ShellPinTarget::Bookmark { key: "site".into() }, true).unwrap();
        let original = pins().unwrap();
        let reversed: Vec<_> = original.iter().rev().cloned().collect();
        reorder_pins(reversed.clone()).unwrap();
        assert_eq!(pins().unwrap(), reversed);
        assert_eq!(
            ShellManager::open(dir.path())
                .unwrap()
                .snapshot()
                .pins
                .items,
            reversed
        );
        host.reject_pins.store(true, Ordering::Relaxed);
        assert!(reorder_pins(original).is_err());
        assert_eq!(pins().unwrap(), reversed);
        assert_eq!(
            ShellManager::open(dir.path())
                .unwrap()
                .snapshot()
                .pins
                .items,
            reversed
        );
    }

    #[test]
    fn failed_pin_apply_rolls_back_memory_and_disk() {
        let _guard = test_guard();
        reset_for_test();
        let dir = tempfile::tempdir().unwrap();
        let host = Arc::new(TestHost::default());
        initialize(dir.path(), host.clone()).unwrap();
        host.reject_pins.store(true, Ordering::Relaxed);

        assert_eq!(
            set_pinned(
                ShellPinTarget::Lxapp {
                    key: "app.chat".to_string(),
                },
                true,
            ),
            Err(ShellError::Host("rejected Pins".to_string()))
        );
        assert!(manager().unwrap().snapshot().pins.items.is_empty());
        assert!(
            ShellManager::open(dir.path())
                .unwrap()
                .snapshot()
                .pins
                .items
                .is_empty()
        );
    }
}