//! Pure state mutations on AppState.
//! These don't need channels, async, or PTY runtime.

use tracing::{info, warn};

use crate::detect::{Agent, AgentState};
use crate::events::AppEvent;
use crate::layout::{find_in_direction, NavDirection, PaneId};
use crate::pane::EffectiveStateChange;

use super::state::{AppState, Mode, ToastKind, ToastNotification};

fn is_background_completion_transition(prev_state: AgentState, new_state: AgentState) -> bool {
    matches!(new_state, AgentState::Idle)
        && matches!(prev_state, AgentState::Working | AgentState::Blocked)
}

pub fn notification_sound_for_state_change(
    is_active_tab: bool,
    prev_state: AgentState,
    new_state: AgentState,
) -> Option<crate::sound::Sound> {
    if new_state == prev_state {
        return None;
    }

    match new_state {
        AgentState::Blocked => Some(crate::sound::Sound::Request),
        AgentState::Idle
            if is_background_completion_transition(prev_state, new_state) && !is_active_tab =>
        {
            Some(crate::sound::Sound::Done)
        }
        _ => None,
    }
}

pub fn notification_toast_for_state_change(
    is_active_tab: bool,
    prev_state: AgentState,
    new_state: AgentState,
) -> Option<ToastKind> {
    if is_active_tab || new_state == prev_state {
        return None;
    }

    match new_state {
        AgentState::Blocked => Some(ToastKind::NeedsAttention),
        AgentState::Idle if is_background_completion_transition(prev_state, new_state) => {
            Some(ToastKind::Finished)
        }
        _ => None,
    }
}

fn toast_agent_label(agent_label: &str) -> &str {
    agent_label
}

pub fn notification_context(
    ws: &crate::workspace::Workspace,
    ws_idx: usize,
    pane_id: PaneId,
) -> String {
    let mut context = format!("{} · {}", ws.display_name(), ws_idx + 1);
    if ws.tabs.len() > 1 {
        if let Some(tab_idx) = ws.find_tab_index_for_pane(pane_id) {
            let tab = &ws.tabs[tab_idx];
            context.push_str(&format!(" · {}", tab.display_name()));
        }
    }
    context
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PaneStateUpdate {
    pub pane_id: PaneId,
    pub ws_idx: usize,
    pub previous_agent_label: Option<String>,
    pub previous_known_agent: Option<Agent>,
    pub previous_state: AgentState,
    pub agent_label: Option<String>,
    pub known_agent: Option<Agent>,
    pub state: AgentState,
}

// ---------------------------------------------------------------------------
// Workspace operations
// ---------------------------------------------------------------------------

impl AppState {
    pub(crate) fn pane_is_in_active_tab(&self, ws_idx: usize, pane_id: PaneId) -> bool {
        let Some(active_ws_idx) = self.active else {
            return false;
        };
        if active_ws_idx != ws_idx {
            return false;
        }
        self.workspaces[ws_idx]
            .find_tab_index_for_pane(pane_id)
            .is_some_and(|tab_idx| tab_idx == self.workspaces[ws_idx].active_tab)
    }

    pub fn switch_workspace(&mut self, idx: usize) {
        if idx < self.workspaces.len() {
            self.active = Some(idx);
            self.selected = idx;
            let workspace_id = self.workspaces[idx].id.clone();
            crate::logging::workspace_focused(&workspace_id);
            self.mark_session_dirty();
            if matches!(
                self.agent_panel_scope,
                crate::app::state::AgentPanelScope::CurrentWorkspace
            ) {
                self.agent_panel_scroll = 0;
            }
            self.ensure_workspace_visible(idx);
            if let Some(ws) = self.workspaces.get_mut(idx) {
                let active_tab = ws.active_tab;
                ws.switch_tab(active_tab);
                let tab_id = format!("{}:{}", workspace_id, active_tab + 1);
                crate::logging::tab_focused(&workspace_id, &tab_id);
            }
            self.tab_scroll_follow_active = true;
            self.refresh_tab_bar_view();
        }
    }

    pub(crate) fn ensure_workspace_visible(&mut self, idx: usize) {
        if self.sidebar_collapsed || idx >= self.workspaces.len() {
            return;
        }

        let mut cards = crate::ui::compute_workspace_card_areas(self, self.view.sidebar_rect);
        if cards.is_empty() {
            self.workspace_scroll = idx;
            return;
        }

        let first_idx = cards.first().map(|card| card.ws_idx).unwrap_or(0);
        if idx < first_idx {
            self.workspace_scroll = idx;
            return;
        }

        while cards.last().map(|card| card.ws_idx).unwrap_or(idx) < idx {
            let previous_scroll = self.workspace_scroll;
            self.workspace_scroll = self.workspace_scroll.saturating_add(1);
            if self.workspace_scroll == previous_scroll {
                break;
            }
            cards = crate::ui::compute_workspace_card_areas(self, self.view.sidebar_rect);
            if cards.is_empty() {
                break;
            }
        }
    }

    pub fn switch_tab(&mut self, idx: usize) {
        if let Some(ws_idx) = self.active {
            let Some(ws) = self.workspaces.get_mut(ws_idx) else {
                return;
            };
            ws.switch_tab(idx);
            let workspace_id = ws.id.clone();
            let tab_id = format!("{}:{}", workspace_id, idx + 1);
            crate::logging::tab_focused(&workspace_id, &tab_id);
            self.mark_session_dirty();
            self.tab_scroll_follow_active = true;
            self.refresh_tab_bar_view();
        }
    }

    pub fn next_workspace(&mut self) {
        if !self.workspaces.is_empty() {
            let current = self.active.unwrap_or(self.selected);
            let next = (current + 1) % self.workspaces.len();
            self.switch_workspace(next);
        }
    }

    pub fn previous_workspace(&mut self) {
        if !self.workspaces.is_empty() {
            let current = self.active.unwrap_or(self.selected);
            let prev = if current == 0 {
                self.workspaces.len() - 1
            } else {
                current - 1
            };
            self.switch_workspace(prev);
        }
    }

    pub fn move_workspace(&mut self, source_idx: usize, insert_idx: usize) {
        if source_idx >= self.workspaces.len() || insert_idx > self.workspaces.len() {
            return;
        }

        self.mark_session_dirty();

        let active_id = self.active.map(|idx| self.workspaces[idx].id.clone());
        let selected_id = self
            .workspaces
            .get(self.selected)
            .map(|workspace| workspace.id.clone());

        let workspace = self.workspaces.remove(source_idx);
        let target_idx = if source_idx < insert_idx {
            insert_idx.saturating_sub(1)
        } else {
            insert_idx
        }
        .min(self.workspaces.len());
        self.workspaces.insert(target_idx, workspace);

        self.active = active_id.and_then(|id| self.workspaces.iter().position(|ws| ws.id == id));
        self.selected = selected_id
            .and_then(|id| self.workspaces.iter().position(|ws| ws.id == id))
            .unwrap_or(0);
        self.ensure_workspace_visible(self.selected);
    }

    pub fn scroll_tabs_left(&mut self) {
        self.tab_scroll_follow_active = false;
        self.tab_scroll = self.tab_scroll.saturating_sub(1);
        self.refresh_tab_bar_view();
    }

    pub fn scroll_tabs_right(&mut self) {
        self.tab_scroll_follow_active = false;
        self.tab_scroll = self.tab_scroll.saturating_add(1);
        self.refresh_tab_bar_view();
    }

    pub fn move_tab(&mut self, source_idx: usize, insert_idx: usize) {
        if let Some(ws) = self.active.and_then(|i| self.workspaces.get_mut(i)) {
            if ws.move_tab(source_idx, insert_idx) {
                self.mark_session_dirty();
                self.tab_scroll_follow_active = true;
                self.refresh_tab_bar_view();
            }
        }
    }

    pub fn next_tab(&mut self) {
        if let Some(ws) = self.active.and_then(|i| self.workspaces.get(i)) {
            if !ws.tabs.is_empty() {
                let next = (ws.active_tab + 1) % ws.tabs.len();
                self.switch_tab(next);
            }
        }
    }

    pub fn previous_tab(&mut self) {
        if let Some(ws) = self.active.and_then(|i| self.workspaces.get(i)) {
            if !ws.tabs.is_empty() {
                let prev = if ws.active_tab == 0 {
                    ws.tabs.len() - 1
                } else {
                    ws.active_tab - 1
                };
                self.switch_tab(prev);
            }
        }
    }

    pub fn close_selected_workspace(&mut self) {
        if self.workspaces.is_empty() {
            return;
        }
        self.mark_session_dirty();
        let workspace_id = self.workspaces[self.selected].id.clone();
        crate::logging::workspace_closed(&workspace_id);
        self.workspaces.remove(self.selected);
        if self.workspaces.is_empty() {
            self.active = None;
            self.selected = 0;
            self.workspace_scroll = 0;
            self.tab_scroll = 0;
            self.tab_scroll_follow_active = true;
        } else {
            if self.selected >= self.workspaces.len() {
                self.selected = self.workspaces.len() - 1;
            }
            self.active = Some(self.selected);
            self.workspace_scroll = self
                .workspace_scroll
                .min(self.workspaces.len().saturating_sub(1));
            self.ensure_workspace_visible(self.selected);
            self.tab_scroll_follow_active = true;
            self.refresh_tab_bar_view();
        }
    }

    fn refresh_tab_bar_view(&mut self) {
        let area = self.view.tab_bar_rect;
        let Some(ws) = self.active.and_then(|idx| self.workspaces.get(idx)) else {
            self.tab_scroll = 0;
            self.view.tab_hit_areas.clear();
            self.view.tab_scroll_left_hit_area = ratatui::layout::Rect::default();
            self.view.tab_scroll_right_hit_area = ratatui::layout::Rect::default();
            self.view.new_tab_hit_area = ratatui::layout::Rect::default();
            return;
        };

        let layout = crate::ui::compute_tab_bar_view(
            ws,
            area,
            self.tab_scroll,
            self.tab_scroll_follow_active,
        );
        self.tab_scroll = layout.scroll;
        self.view.tab_hit_areas = layout.tab_hit_areas;
        self.view.tab_scroll_left_hit_area = layout.scroll_left_hit_area;
        self.view.tab_scroll_right_hit_area = layout.scroll_right_hit_area;
        self.view.new_tab_hit_area = layout.new_tab_hit_area;
    }
}

// ---------------------------------------------------------------------------
// Pane operations
// ---------------------------------------------------------------------------

impl AppState {
    pub fn navigate_pane(&mut self, direction: NavDirection) {
        let panes = &self.view.pane_infos;
        if let Some(focused) = panes.iter().find(|p| p.is_focused) {
            if let Some(target) = find_in_direction(focused, direction, panes) {
                if let Some(tab) = self
                    .active
                    .and_then(|i| self.workspaces.get_mut(i))
                    .and_then(|ws| ws.active_tab_mut())
                {
                    tab.layout.focus_pane(target);
                    self.mark_session_dirty();
                }
            }
        }
    }

    pub fn resize_pane(&mut self, direction: NavDirection) {
        if let Some(first) = self.view.pane_infos.first() {
            let area = self
                .view
                .pane_infos
                .iter()
                .fold(first.rect, |acc, p| acc.union(p.rect));
            if let Some(tab) = self
                .active
                .and_then(|i| self.workspaces.get_mut(i))
                .and_then(|ws| ws.active_tab_mut())
            {
                tab.layout.resize_focused(direction, 0.05, area);
                self.mark_session_dirty();
            }
        }
    }

    pub fn cycle_pane(&mut self, reverse: bool) {
        if let Some(tab) = self
            .active
            .and_then(|i| self.workspaces.get_mut(i))
            .and_then(|ws| ws.active_tab_mut())
        {
            if reverse {
                tab.layout.focus_prev();
            } else {
                tab.layout.focus_next();
            }
            self.mark_session_dirty();
        }
    }

    pub fn toggle_fullscreen(&mut self) {
        if let Some(tab) = self
            .active
            .and_then(|i| self.workspaces.get_mut(i))
            .and_then(|ws| ws.active_tab_mut())
        {
            if tab.layout.pane_count() > 1 {
                tab.zoomed = !tab.zoomed;
                self.mark_session_dirty();
            }
        }
    }

    pub fn close_pane(&mut self) {
        self.mark_session_dirty();
        let should_close_workspace = self
            .active
            .and_then(|i| self.workspaces.get_mut(i))
            .is_some_and(|ws| ws.close_focused());
        if should_close_workspace {
            self.close_selected_workspace();
        }
    }

    pub fn close_tab(&mut self) {
        self.mark_session_dirty();
        let should_close_workspace = self
            .active
            .and_then(|i| self.workspaces.get(i))
            .is_some_and(|ws| ws.tabs.len() <= 1);
        if should_close_workspace {
            self.close_selected_workspace();
            return;
        }
        if let Some(ws_idx) = self.active {
            let Some(ws) = self.workspaces.get_mut(ws_idx) else {
                return;
            };
            let workspace_id = ws.id.clone();
            let closing_tab_id = format!("{}:{}", workspace_id, ws.active_tab + 1);
            ws.close_active_tab();
            crate::logging::tab_closed(&workspace_id, &closing_tab_id);
            self.tab_scroll_follow_active = true;
            self.refresh_tab_bar_view();
        }
    }
}

// ---------------------------------------------------------------------------
// Selection
// ---------------------------------------------------------------------------

impl AppState {
    pub fn clear_selection(&mut self) {
        self.selection = None;
    }

    pub fn copy_selection(&mut self) {
        let text = {
            let sel = match self.selection.as_mut() {
                Some(s) => {
                    if !s.finish() {
                        self.selection = None;
                        return;
                    }
                    s
                }
                None => return,
            };

            let ws = match self.active.and_then(|i| self.workspaces.get(i)) {
                Some(ws) => ws,
                None => {
                    self.selection = None;
                    return;
                }
            };

            let rt = match ws.runtime(sel.pane_id) {
                Some(r) => r,
                None => {
                    self.selection = None;
                    return;
                }
            };

            rt.extract_selection(sel)
        };

        if let Some(text) = text {
            if !text.is_empty() {
                self.request_clipboard_write = Some(text.into_bytes());
                info!("copied selection to clipboard");
            }
        }

        self.selection = None;
    }
}

// ---------------------------------------------------------------------------
// Event handling
// ---------------------------------------------------------------------------

impl AppState {
    pub fn handle_app_event(&mut self, event: AppEvent) -> Vec<PaneStateUpdate> {
        match event {
            AppEvent::PaneDied { pane_id } => {
                self.handle_pane_died(pane_id);
                Vec::new()
            }
            AppEvent::UpdateReady { version } => {
                self.update_available = Some(version.clone());
                self.latest_release_notes_available = true;
                self.update_dismissed = true;
                if matches!(
                    self.toast_config.delivery,
                    crate::config::ToastDelivery::Herdr
                ) {
                    self.toast = Some(ToastNotification {
                        kind: ToastKind::UpdateInstalled,
                        title: format!("v{version} available"),
                        context: "detach, then run `herdr update`".to_string(),
                    });
                }
                Vec::new()
            }
            AppEvent::StateChanged {
                pane_id,
                agent,
                state,
            } => self
                .update_pane_state(pane_id, |pane| pane.set_detected_state(agent, state))
                .into_iter()
                .collect(),
            AppEvent::HookStateReported {
                pane_id,
                source,
                agent_label,
                state,
                message,
            } => self
                .update_pane_state(pane_id, |pane| {
                    pane.set_hook_authority(source, agent_label, state, message)
                })
                .into_iter()
                .collect(),
            AppEvent::HookAuthorityCleared { pane_id, source } => self
                .update_pane_state(pane_id, |pane| pane.clear_hook_authority(source.as_deref()))
                .into_iter()
                .collect(),
            AppEvent::HookAgentReleased {
                pane_id,
                source,
                agent_label,
                ..
            } => self
                .update_pane_state(pane_id, |pane| pane.release_agent(&source, &agent_label))
                .into_iter()
                .collect(),
            // Intercepted in App::handle_internal_event before reaching this
            // dispatch; never touches AppState.
            AppEvent::ClipboardWrite { .. } => Vec::new(),
        }
    }

    fn update_pane_state<F>(&mut self, pane_id: PaneId, update: F) -> Option<PaneStateUpdate>
    where
        F: FnOnce(&mut crate::pane::PaneState) -> Option<EffectiveStateChange>,
    {
        let ws_idx = self
            .workspaces
            .iter()
            .position(|ws| ws.pane_state(pane_id).is_some())?;
        let change = {
            let pane = self.workspaces[ws_idx]
                .tabs
                .iter_mut()
                .find_map(|tab| tab.panes.get_mut(&pane_id))?;
            update(pane)?
        };
        let update = PaneStateUpdate {
            pane_id,
            ws_idx,
            previous_agent_label: change.previous_agent_label.clone(),
            previous_known_agent: change.previous_known_agent,
            previous_state: change.previous_state,
            agent_label: change.agent_label.clone(),
            known_agent: change.known_agent,
            state: change.state,
        };
        self.apply_pane_state_change(ws_idx, pane_id, &change);
        Some(update)
    }

    fn apply_pane_state_change(
        &mut self,
        ws_idx: usize,
        pane_id: PaneId,
        change: &EffectiveStateChange,
    ) {
        let is_active_tab = self.pane_is_in_active_tab(ws_idx, pane_id);
        let Some(pane) = self.workspaces[ws_idx]
            .tabs
            .iter_mut()
            .find_map(|tab| tab.panes.get_mut(&pane_id))
        else {
            return;
        };

        if is_background_completion_transition(change.previous_state, change.state)
            && !is_active_tab
        {
            pane.seen = false;
        }

        if self.sound.allows(change.known_agent) {
            if let Some(sound) = notification_sound_for_state_change(
                is_active_tab,
                change.previous_state,
                change.state,
            ) {
                crate::sound::play(sound, &self.sound);
            }
        }

        if matches!(
            self.toast_config.delivery,
            crate::config::ToastDelivery::Herdr
        ) {
            if let (Some(agent_label), Some(kind)) = (
                change.agent_label.as_deref(),
                notification_toast_for_state_change(
                    is_active_tab,
                    change.previous_state,
                    change.state,
                ),
            ) {
                let event_text = match kind {
                    ToastKind::NeedsAttention => "needs attention",
                    ToastKind::Finished => "finished",
                    ToastKind::UpdateInstalled => "updated",
                };
                let context = notification_context(&self.workspaces[ws_idx], ws_idx, pane_id);
                self.toast = Some(ToastNotification {
                    kind,
                    title: format!("{} {}", toast_agent_label(agent_label), event_text),
                    context,
                });
            }
        }
    }

    fn handle_pane_died(&mut self, pane_id: PaneId) {
        let ws_idx = self
            .workspaces
            .iter()
            .position(|ws| ws.find_tab_index_for_pane(pane_id).is_some());

        let Some(ws_idx) = ws_idx else {
            warn!(pane = pane_id.raw(), "PaneDied for unknown pane");
            return;
        };

        let should_close_workspace = {
            let ws = &mut self.workspaces[ws_idx];
            ws.remove_pane(pane_id)
        };
        self.mark_session_dirty();

        if should_close_workspace {
            self.workspaces.remove(ws_idx);
            if self.workspaces.is_empty() {
                self.active = None;
                self.selected = 0;
                if self.mode == Mode::Terminal {
                    self.mode = Mode::Navigate;
                }
            } else {
                if let Some(active) = self.active {
                    if active >= self.workspaces.len() {
                        self.active = Some(self.workspaces.len() - 1);
                    }
                }
                if self.selected >= self.workspaces.len() {
                    self.selected = self.workspaces.len() - 1;
                }
            }
        }
    }
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

#[cfg(test)]
mod tests {
    use super::*;
    use crate::detect::{Agent, AgentState};
    use crate::workspace::Workspace;
    use ratatui::layout::Direction;

    fn app_with_workspaces(names: &[&str]) -> AppState {
        let mut state = AppState::test_new();
        for name in names {
            let ws = Workspace::test_new(name);
            state.workspaces.push(ws);
        }
        if !state.workspaces.is_empty() {
            state.active = Some(0);
            state.mode = Mode::Terminal;
        }
        state
    }

    #[test]
    fn update_ready_sets_explicit_upgrade_toast() {
        let mut state = AppState::test_new();
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;

        let updates = state.handle_app_event(crate::events::AppEvent::UpdateReady {
            version: "0.5.0".into(),
        });

        assert!(updates.is_empty());
        assert_eq!(state.update_available.as_deref(), Some("0.5.0"));
        assert!(state.latest_release_notes_available);
        let toast = state.toast.as_ref().expect("update toast");
        assert_eq!(toast.title, "v0.5.0 available");
        assert_eq!(toast.context, "detach, then run `herdr update`");
    }

    #[test]
    fn switch_workspace_updates_active_and_selected() {
        let mut state = app_with_workspaces(&["a", "b", "c"]);
        state.switch_workspace(2);
        assert_eq!(state.active, Some(2));
        assert_eq!(state.selected, 2);
    }

    #[test]
    fn switch_workspace_keeps_selected_visible_in_scrolled_sidebar() {
        let mut state = app_with_workspaces(&["a", "b", "c", "d", "e", "f", "g", "h"]);
        crate::ui::compute_view(&mut state, ratatui::layout::Rect::new(0, 0, 26, 14));

        state.switch_workspace(7);
        crate::ui::compute_view(&mut state, ratatui::layout::Rect::new(0, 0, 26, 14));

        assert!(state
            .view
            .workspace_card_areas
            .iter()
            .any(|card| card.ws_idx == 7));
    }

    #[test]
    fn switch_workspace_marks_panes_seen() {
        let mut state = app_with_workspaces(&["a", "b"]);
        // Mark a pane in workspace 1 as unseen
        let id = *state.workspaces[1].panes.keys().next().unwrap();
        state.workspaces[1].panes.get_mut(&id).unwrap().seen = false;

        state.switch_workspace(1);
        assert!(state.workspaces[1].panes.get(&id).unwrap().seen);
    }

    #[test]
    fn switch_workspace_out_of_bounds_is_noop() {
        let mut state = app_with_workspaces(&["a"]);
        state.switch_workspace(5);
        assert_eq!(state.active, Some(0));
    }

    #[test]
    fn move_workspace_reorders_without_changing_logical_selection() {
        let mut state = app_with_workspaces(&["a", "b", "c"]);
        let active_id = state.workspaces[1].id.clone();
        let selected_id = state.workspaces[2].id.clone();
        state.active = Some(1);
        state.selected = 2;

        state.move_workspace(1, 0);

        let names: Vec<_> = state
            .workspaces
            .iter()
            .map(|ws| ws.display_name())
            .collect();
        assert_eq!(names, vec!["b", "a", "c"]);
        assert_eq!(state.active, Some(0));
        assert_eq!(state.selected, 2);
        assert_eq!(state.workspaces[state.active.unwrap()].id, active_id);
        assert_eq!(state.workspaces[state.selected].id, selected_id);
    }

    #[test]
    fn move_workspace_accepts_insert_at_end() {
        let mut state = app_with_workspaces(&["a", "b", "c"]);

        state.move_workspace(0, state.workspaces.len());

        let names: Vec<_> = state
            .workspaces
            .iter()
            .map(|ws| ws.display_name())
            .collect();
        assert_eq!(names, vec!["b", "c", "a"]);
    }

    #[test]
    fn close_workspace_adjusts_indices() {
        let mut state = app_with_workspaces(&["a", "b", "c"]);
        state.selected = 1;
        state.active = Some(1);

        state.close_selected_workspace();

        assert_eq!(state.workspaces.len(), 2);
        assert_eq!(state.selected, 1);
        assert_eq!(state.active, Some(1));
        assert_eq!(state.workspaces[1].custom_name.as_deref(), Some("c"));
    }

    #[test]
    fn close_last_workspace_clears_active() {
        let mut state = app_with_workspaces(&["only"]);
        state.selected = 0;
        state.close_selected_workspace();

        assert!(state.workspaces.is_empty());
        assert_eq!(state.active, None);
        assert_eq!(state.selected, 0);
    }

    #[test]
    fn close_workspace_at_end_adjusts_selected() {
        let mut state = app_with_workspaces(&["a", "b"]);
        state.selected = 1;
        state.active = Some(1);

        state.close_selected_workspace();

        assert_eq!(state.workspaces.len(), 1);
        assert_eq!(state.selected, 0);
        assert_eq!(state.active, Some(0));
    }

    #[test]
    fn pane_died_last_pane_removes_workspace() {
        let mut state = app_with_workspaces(&["a", "b"]);
        let pane_id = *state.workspaces[0].panes.keys().next().unwrap();

        state.handle_pane_died(pane_id);

        assert_eq!(state.workspaces.len(), 1);
        assert_eq!(state.workspaces[0].custom_name.as_deref(), Some("b"));
    }

    #[test]
    fn pane_died_last_workspace_enters_navigate() {
        let mut state = app_with_workspaces(&["only"]);
        state.mode = Mode::Terminal;
        let pane_id = *state.workspaces[0].panes.keys().next().unwrap();

        state.handle_pane_died(pane_id);

        assert!(state.workspaces.is_empty());
        assert_eq!(state.mode, Mode::Navigate);
    }

    #[test]
    fn pane_died_multi_pane_keeps_workspace() {
        let mut state = app_with_workspaces(&["test"]);
        let second_id = state.workspaces[0].test_split(Direction::Horizontal);

        state.handle_pane_died(second_id);

        assert_eq!(state.workspaces.len(), 1);
        assert_eq!(state.workspaces[0].panes.len(), 1);
    }

    #[test]
    fn pane_died_unknown_pane_is_noop() {
        let mut state = app_with_workspaces(&["test"]);
        let fake_id = PaneId::from_raw(9999);

        state.handle_pane_died(fake_id);

        assert_eq!(state.workspaces.len(), 1);
    }

    #[test]
    fn state_changed_updates_pane() {
        let mut state = app_with_workspaces(&["test"]);
        let pane_id = *state.workspaces[0].panes.keys().next().unwrap();

        state.handle_app_event(AppEvent::StateChanged {
            pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Working,
        });

        let pane = state.workspaces[0].panes.get(&pane_id).unwrap();
        assert_eq!(pane.state, AgentState::Working);
        assert_eq!(pane.detected_agent, Some(Agent::Pi));
    }

    #[test]
    fn state_changed_idle_in_background_marks_unseen() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        let bg_pane_id = *state.workspaces[1].panes.keys().next().unwrap();

        // First set it to Working
        state.workspaces[1]
            .panes
            .get_mut(&bg_pane_id)
            .unwrap()
            .state = AgentState::Working;

        // Now transition to Idle while in background
        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Idle,
        });

        let pane = state.workspaces[1].panes.get(&bg_pane_id).unwrap();
        assert!(!pane.seen);
    }

    #[test]
    fn initial_idle_in_background_stays_seen() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        let bg_pane_id = *state.workspaces[1].panes.keys().next().unwrap();

        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Idle,
        });

        let pane = state.workspaces[1].panes.get(&bg_pane_id).unwrap();
        assert!(pane.seen);
    }

    #[test]
    fn waiting_sound_plays_even_in_active_workspace() {
        assert_eq!(
            notification_sound_for_state_change(true, AgentState::Working, AgentState::Blocked),
            Some(crate::sound::Sound::Request)
        );
    }

    #[test]
    fn done_sound_only_plays_in_background() {
        assert_eq!(
            notification_sound_for_state_change(false, AgentState::Working, AgentState::Idle),
            Some(crate::sound::Sound::Done)
        );
        assert_eq!(
            notification_sound_for_state_change(true, AgentState::Working, AgentState::Idle),
            None
        );
        assert_eq!(
            notification_sound_for_state_change(false, AgentState::Unknown, AgentState::Idle),
            None
        );
    }

    #[test]
    fn background_waiting_sets_attention_toast() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        let bg_pane_id = *state.workspaces[1].panes.keys().next().unwrap();

        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Blocked,
        });

        let toast = state.toast.as_ref().unwrap();
        assert_eq!(toast.kind, ToastKind::NeedsAttention);
        assert_eq!(toast.title, "pi needs attention");
        assert_eq!(toast.context, "background · 2");
    }

    #[test]
    fn hook_reported_unknown_agent_sets_toast_title_from_label() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        let bg_pane_id = *state.workspaces[1].panes.keys().next().unwrap();

        state.handle_app_event(AppEvent::HookStateReported {
            pane_id: bg_pane_id,
            source: "custom:hermes".into(),
            agent_label: "hermes".into(),
            state: AgentState::Blocked,
            message: None,
        });

        let toast = state.toast.as_ref().unwrap();
        assert_eq!(toast.kind, ToastKind::NeedsAttention);
        assert_eq!(toast.title, "hermes needs attention");
        assert_eq!(toast.context, "background · 2");
    }

    #[test]
    fn background_idle_sets_finished_toast() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        let bg_pane_id = *state.workspaces[1].panes.keys().next().unwrap();
        state.workspaces[1]
            .panes
            .get_mut(&bg_pane_id)
            .unwrap()
            .state = AgentState::Working;

        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Droid),
            state: AgentState::Idle,
        });

        let toast = state.toast.as_ref().unwrap();
        assert_eq!(toast.kind, ToastKind::Finished);
        assert_eq!(toast.title, "droid finished");
        assert_eq!(toast.context, "background · 2");
    }

    #[test]
    fn background_toast_includes_tab_name_when_workspace_has_multiple_tabs() {
        let mut state = app_with_workspaces(&["active", "background"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        state.workspaces[1].tabs[0].set_custom_name("main".into());
        let second_tab = state.workspaces[1].test_add_tab(Some("logs"));
        let bg_pane_id = state.workspaces[1].tabs[second_tab].root_pane;

        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Blocked,
        });

        let toast = state.toast.as_ref().unwrap();
        assert_eq!(toast.kind, ToastKind::NeedsAttention);
        assert_eq!(toast.title, "pi needs attention");
        assert_eq!(toast.context, "background · 2 · logs");
    }

    #[test]
    fn background_tab_in_active_workspace_still_sets_toast() {
        let mut state = app_with_workspaces(&["active"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        state.workspaces[0].tabs[0].set_custom_name("main".into());
        let second_tab = state.workspaces[0].test_add_tab(Some("logs"));
        let bg_pane_id = state.workspaces[0].tabs[second_tab].root_pane;

        state.handle_app_event(AppEvent::StateChanged {
            pane_id: bg_pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Blocked,
        });

        let toast = state.toast.as_ref().unwrap();
        assert_eq!(toast.kind, ToastKind::NeedsAttention);
        assert_eq!(toast.title, "pi needs attention");
        assert_eq!(toast.context, "active · 1 · logs");
    }

    #[test]
    fn active_workspace_active_tab_does_not_set_toast() {
        let mut state = app_with_workspaces(&["active"]);
        state.active = Some(0);
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;
        let pane_id = *state.workspaces[0].panes.keys().next().unwrap();

        state.handle_app_event(AppEvent::StateChanged {
            pane_id,
            agent: Some(Agent::Pi),
            state: AgentState::Blocked,
        });

        assert!(state.toast.is_none());
    }

    #[test]
    fn update_ready_sets_manual_update_toast() {
        let mut state = AppState::test_new();
        state.toast_config.delivery = crate::config::ToastDelivery::Herdr;

        let updates = state.handle_app_event(AppEvent::UpdateReady {
            version: "0.5.0".into(),
        });

        assert!(updates.is_empty());
        assert_eq!(state.update_available.as_deref(), Some("0.5.0"));
        assert!(state.latest_release_notes_available);
        assert!(state.update_dismissed);
        let toast = state.toast.as_ref().expect("update toast");
        assert_eq!(toast.kind, ToastKind::UpdateInstalled);
        assert_eq!(toast.title, "v0.5.0 available");
        assert_eq!(toast.context, "detach, then run `herdr update`");
    }

    #[test]
    fn toggle_fullscreen_works() {
        let mut state = app_with_workspaces(&["test"]);
        state.workspaces[0].test_split(Direction::Horizontal);

        assert!(!state.workspaces[0].zoomed);
        state.toggle_fullscreen();
        assert!(state.workspaces[0].zoomed);
        state.toggle_fullscreen();
        assert!(!state.workspaces[0].zoomed);
    }

    #[test]
    fn toggle_fullscreen_single_pane_noop() {
        let mut state = app_with_workspaces(&["test"]);
        state.toggle_fullscreen();
        assert!(!state.workspaces[0].zoomed);
    }

    #[test]
    fn close_pane_removes_from_workspace() {
        let mut state = app_with_workspaces(&["test"]);
        state.workspaces[0].test_split(Direction::Horizontal);
        assert_eq!(state.workspaces[0].panes.len(), 2);

        state.close_pane();
        assert_eq!(state.workspaces[0].panes.len(), 1);
    }
}