agentty 0.10.4

use std::io;

use crossterm::event::{self, KeyCode, KeyEvent};
use ratatui::Terminal;
use ratatui::backend::Backend;
use tracing::warn;

use crate::app::session::{SessionTaskService, remote_branch_name_from_upstream_ref};
use crate::app::{
    self, App, AppEvent, ReviewCacheEntry, diff_content_hash, is_review_loading_status_message,
    review_loading_message,
};
use crate::domain::agent::AgentModel;
use crate::domain::input::InputState;
use crate::domain::session::{FollowUpTaskAction, PublishBranchAction, SessionId, Status};
use crate::domain::transcript_notice::TranscriptNotice;
use crate::runtime::EventResult;
use crate::runtime::mode::confirmation::DEFAULT_OPTION_INDEX;
use crate::runtime::mode::input_key::is_insertable_char_key;
use crate::ui::component::session_output::SessionOutputLineContext;
use crate::ui::page::session_chat::SessionChatPage;
use crate::ui::state::app_mode::{
    AppMode, ConfirmationIntent, ConfirmationViewMode, DiffRightPanel, HelpContext,
};
use crate::ui::state::help_action::{self, ViewSessionState};
use crate::ui::state::prompt::{PromptAttachmentState, PromptHistoryState};

#[derive(Clone)]
struct ViewContext {
    review_status_message: Option<String>,
    review_text: Option<String>,
    scroll_offset: Option<u16>,
    session_id: SessionId,
    session_index: usize,
}

#[derive(Clone, Copy)]
struct ViewMetrics {
    total_lines: u16,
    view_height: u16,
}

/// Pending review and scroll updates produced by one key event in session-view
/// mode.
struct ViewPendingUpdate {
    review_status_message: Option<String>,
    review_text: Option<String>,
    scroll_offset: Option<u16>,
}

impl ViewPendingUpdate {
    /// Builds update state seeded from the current view mode values.
    fn from_context(view_context: &ViewContext) -> Self {
        Self {
            review_status_message: view_context.review_status_message.clone(),
            review_text: view_context.review_text.clone(),
            scroll_offset: view_context.scroll_offset,
        }
    }
}

/// Borrowed per-key context used while processing one session-view key event.
struct ViewKeyContext<'a> {
    context: &'a ViewContext,
    metrics: ViewMetrics,
    session_snapshot: &'a ViewSessionSnapshot,
}

/// Snapshot of session-derived state used by view-mode key handling.
struct ViewSessionSnapshot {
    can_continue_terminal_session: bool,
    can_open_worktree: bool,
    can_start_staged_session: bool,
    follow_up_task_action: Option<FollowUpTaskAction>,
    publish_pull_request_action: Option<PublishBranchAction>,
    session_state: ViewSessionState,
    session_status: Status,
}

impl ViewSessionSnapshot {
    /// Returns whether the active session can enter the merge queue from view
    /// mode.
    fn can_merge_session(&self) -> bool {
        is_view_action_allowed(self.session_status)
            && self.session_state != ViewSessionState::StackedDraft
    }

    /// Returns whether the active session can start a rebase from view mode.
    fn can_rebase_session(&self) -> bool {
        is_view_rebase_allowed(self.session_status)
            && self.session_state != ViewSessionState::StackedDraft
    }
}

/// Fallback copy shown when a review-ready session has no diff to inspect.
const REVIEW_NO_DIFF_MESSAGE: &str = "No diff changes found for review.";

/// Processes view-mode key presses and keeps shortcut availability aligned with
/// session status (`o` disabled outside editable/review-ready local
/// worktrees, and diff/review available for review-ready statuses).
pub(crate) async fn handle<B: Backend>(
    app: &mut App,
    terminal: &mut Terminal<B>,
    key: KeyEvent,
) -> io::Result<EventResult>
where
    B::Error: std::error::Error + Send + Sync + 'static,
{
    let Some(view_context) = view_context(app) else {
        return Ok(EventResult::Continue);
    };
    let view_metrics = view_metrics(app, terminal, &view_context)?;
    let mut pending_update = ViewPendingUpdate::from_context(&view_context);

    let Some(view_session_snapshot) = view_session_snapshot(app, &view_context) else {
        return Ok(EventResult::Continue);
    };
    let view_key_context = ViewKeyContext {
        context: &view_context,
        metrics: view_metrics,
        session_snapshot: &view_session_snapshot,
    };

    if !handle_view_key(app, key, view_key_context, &mut pending_update).await {
        return Ok(EventResult::Continue);
    }

    apply_view_scroll_and_output_mode(
        app,
        pending_update.review_status_message,
        pending_update.review_text,
        pending_update.scroll_offset,
    );

    Ok(EventResult::Continue)
}

/// Applies one view-mode key press and updates pending output/scroll state.
///
/// Returns `false` when key handling already transitioned mode and should skip
/// applying pending view updates.
async fn handle_view_key(
    app: &mut App,
    key: KeyEvent,
    view_key_context: ViewKeyContext<'_>,
    pending_update: &mut ViewPendingUpdate,
) -> bool {
    let view_context = view_key_context.context;
    let view_metrics = view_key_context.metrics;
    let view_session_snapshot = view_key_context.session_snapshot;

    if let Some(should_apply_pending_update) = handle_primary_view_key(
        app,
        key,
        view_context,
        view_session_snapshot,
        pending_update,
    )
    .await
    {
        return should_apply_pending_update;
    }

    if handle_scroll_key(key, view_metrics, pending_update) {
        return true;
    }

    if let Some(should_apply_pending_update) = handle_workflow_view_key(
        app,
        key,
        view_context,
        view_session_snapshot,
        pending_update,
    )
    .await
    {
        return should_apply_pending_update;
    }

    true
}

/// Handles primary session-view actions that do not need diff/review routing.
async fn handle_primary_view_key(
    app: &mut App,
    key: KeyEvent,
    view_context: &ViewContext,
    view_session_snapshot: &ViewSessionSnapshot,
    pending_update: &ViewPendingUpdate,
) -> Option<bool> {
    match key.code {
        KeyCode::Char('q') => {
            app.mode = AppMode::List;
        }
        KeyCode::Char('o') if view_session_snapshot.can_open_worktree => {
            open_worktree_for_view_session(app, view_context).await;
        }
        KeyCode::Char('l') if view_session_snapshot.follow_up_task_action.is_some() => {
            if let Err(error) = app
                .launch_or_open_selected_follow_up_task(&view_context.session_id)
                .await
            {
                app.append_output_for_session(
                    &view_context.session_id,
                    &TranscriptNotice::FollowUpTaskError.format(error),
                )
                .await;
            }

            return Some(false);
        }
        KeyCode::Char('s') if view_session_snapshot.can_start_staged_session => {
            if let Err(error) = app.start_staged_session(&view_context.session_id).await {
                app.append_output_for_session(
                    &view_context.session_id,
                    &TranscriptNotice::StartError.format(error),
                )
                .await;
            }

            return Some(false);
        }
        KeyCode::Char('c')
            if key.modifiers == event::KeyModifiers::NONE
                && view_session_snapshot.can_continue_terminal_session =>
        {
            open_continue_confirmation(app, view_context);

            return Some(false);
        }
        KeyCode::Char('[') if app.has_multiple_follow_up_tasks(&view_context.session_id) => {
            app.select_previous_follow_up_task(&view_context.session_id);
        }
        KeyCode::Char(']') if app.has_multiple_follow_up_tasks(&view_context.session_id) => {
            app.select_next_follow_up_task(&view_context.session_id);
        }
        KeyCode::Enter if is_view_chat_allowed(view_session_snapshot.session_status) => {
            switch_view_to_prompt(
                app,
                view_context,
                PromptHistoryState::new(session_prompt_history_entries(
                    app.sessions.session_at(view_context.session_index)?,
                )),
                InputState::default(),
                pending_update.scroll_offset,
            );
        }
        KeyCode::Char('/')
            if is_view_action_allowed(view_session_snapshot.session_status)
                && is_insertable_char_key(key) =>
        {
            switch_view_to_prompt(
                app,
                view_context,
                PromptHistoryState::new(session_prompt_history_entries(
                    app.sessions.session_at(view_context.session_index)?,
                )),
                InputState::with_text("/".to_string()),
                pending_update.scroll_offset,
            );
        }
        _ => return None,
    }

    Some(true)
}

/// Handles scroll-only keys in session view.
fn handle_scroll_key(
    key: KeyEvent,
    view_metrics: ViewMetrics,
    pending_update: &mut ViewPendingUpdate,
) -> bool {
    match key.code {
        KeyCode::Char('j') | KeyCode::Down => {
            pending_update.scroll_offset =
                scroll_offset_down(pending_update.scroll_offset, view_metrics, 1);
        }
        KeyCode::Char('k') | KeyCode::Up => {
            pending_update.scroll_offset = Some(scroll_offset_up(
                pending_update.scroll_offset,
                view_metrics,
                1,
            ));
        }
        KeyCode::Char('g') => pending_update.scroll_offset = Some(0),
        KeyCode::Char('G') => pending_update.scroll_offset = None,
        KeyCode::Char('d') if key.modifiers.contains(event::KeyModifiers::CONTROL) => {
            pending_update.scroll_offset =
                scroll_offset_half_page_down(pending_update.scroll_offset, view_metrics);
        }
        KeyCode::Char('u') if key.modifiers.contains(event::KeyModifiers::CONTROL) => {
            pending_update.scroll_offset = Some(scroll_offset_half_page_up(
                pending_update.scroll_offset,
                view_metrics,
            ));
        }
        _ => return false,
    }

    true
}

/// Handles workflow actions in session view such as diff, publish, review,
/// merge, rebase, cancellation, and help.
async fn handle_workflow_view_key(
    app: &mut App,
    key: KeyEvent,
    view_context: &ViewContext,
    view_session_snapshot: &ViewSessionSnapshot,
    pending_update: &mut ViewPendingUpdate,
) -> Option<bool> {
    match key.code {
        KeyCode::Char('d')
            if !key.modifiers.contains(event::KeyModifiers::CONTROL)
                && is_view_diff_allowed(view_session_snapshot.session_status) =>
        {
            show_diff_for_view_session(app, view_context).await;
        }
        KeyCode::Char(character)
            if character.eq_ignore_ascii_case(&'p')
                && !key.modifiers.contains(event::KeyModifiers::CONTROL)
                && view_session_snapshot.publish_pull_request_action.is_some() =>
        {
            let Some(publish_pull_request_action) =
                view_session_snapshot.publish_pull_request_action
            else {
                return Some(true);
            };
            open_publish_branch_input(app, view_context, publish_pull_request_action);

            return Some(false);
        }
        KeyCode::Char(character)
            if character.eq_ignore_ascii_case(&'f')
                && !key.modifiers.contains(event::KeyModifiers::CONTROL)
                && is_view_review_allowed(view_session_snapshot.session_status) =>
        {
            open_or_regenerate_review(app, view_context, pending_update).await;
        }
        KeyCode::Char('m') if view_session_snapshot.can_merge_session() => {
            open_merge_confirmation(app, view_context);
        }
        KeyCode::Char('r') if view_session_snapshot.can_rebase_session() => {
            rebase_view_session(app, &view_context.session_id).await;
        }
        KeyCode::Char('c')
            if key.modifiers.contains(event::KeyModifiers::CONTROL)
                && view_session_snapshot.session_status == Status::InProgress =>
        {
            end_in_progress_turn(app, &view_context.session_id).await;

            return Some(false);
        }
        KeyCode::Char('?') => {
            open_view_help_overlay(app, view_context, view_session_snapshot);
            return Some(false);
        }
        _ => return None,
    }

    Some(true)
}

/// Opens a merge confirmation overlay for the active view session.
///
/// The body text asks whether the current session should be added to the
/// merge queue.
fn open_merge_confirmation(app: &mut App, view_context: &ViewContext) {
    app.mode = AppMode::Confirmation {
        confirmation_intent: ConfirmationIntent::MergeSession,
        confirmation_message: "Add this session to merge queue?".to_string(),
        confirmation_title: "Confirm Merge".to_string(),
        restore_view: Some(confirmation_view_mode(view_context)),
        session_id: Some(view_context.session_id.clone()),
        selected_confirmation_index: DEFAULT_OPTION_INDEX,
    };
}

/// Opens a continuation confirmation overlay for one terminal session.
///
/// The confirmation explains that Agentty will create a new draft session
/// seeded with initial context so the user can add more notes before starting
/// it.
fn open_continue_confirmation(app: &mut App, view_context: &ViewContext) {
    app.mode = AppMode::Confirmation {
        confirmation_intent: ConfirmationIntent::ContinueSession,
        confirmation_message: "Create a new draft session with initial context from this session?"
            .to_string(),
        confirmation_title: "Confirm Continue".to_string(),
        restore_view: Some(confirmation_view_mode(view_context)),
        session_id: Some(view_context.session_id.clone()),
        selected_confirmation_index: DEFAULT_OPTION_INDEX,
    };
}

/// Opens the viewed session worktree directly or shows a command selector when
/// multiple open commands are configured.
async fn open_worktree_for_view_session(app: &mut App, view_context: &ViewContext) {
    let open_commands = app.configured_open_commands();
    if open_commands.len() > 1 {
        app.mode = AppMode::OpenCommandSelector {
            commands: open_commands,
            restore_view: confirmation_view_mode(view_context),
            selected_command_index: 0,
        };

        return;
    }

    let selected_open_command = open_commands.first().map(String::as_str);

    app.open_session_worktree_in_tmux_with_command(selected_open_command)
        .await;
}

/// Builds the view-mode snapshot used to restore chat context when a merge
/// confirmation is dismissed.
fn confirmation_view_mode(view_context: &ViewContext) -> ConfirmationViewMode {
    ConfirmationViewMode {
        review_status_message: view_context.review_status_message.clone(),
        review_text: view_context.review_text.clone(),
        scroll_offset: view_context.scroll_offset,
        session_id: view_context.session_id.clone(),
    }
}

/// Opens focused review or shows a regeneration confirmation popup.
///
/// When a review result (or error) is already present, shows a confirmation
/// popup before regenerating. If a generation is already in flight (loading),
/// the press is ignored to avoid spawning duplicate background tasks.
/// Otherwise, loads or starts focused review output and resets scroll to
/// bottom-aligned mode.
async fn open_or_regenerate_review(
    app: &mut App,
    view_context: &ViewContext,
    pending_update: &mut ViewPendingUpdate,
) {
    let is_loading = pending_update
        .review_status_message
        .as_deref()
        .is_some_and(is_review_loading_status_message);
    if is_loading {
        return;
    }

    if pending_update.review_text.is_some() || pending_update.review_status_message.is_some() {
        app.mode = AppMode::Confirmation {
            confirmation_intent: ConfirmationIntent::RegenerateReview,
            confirmation_message: "Regenerate focused review?".to_string(),
            confirmation_title: "Confirm Regenerate".to_string(),
            restore_view: Some(confirmation_view_mode(view_context)),
            session_id: Some(view_context.session_id.clone()),
            selected_confirmation_index: DEFAULT_OPTION_INDEX,
        };

        return;
    }

    open_review_output_mode(
        app,
        view_context,
        &mut pending_update.review_status_message,
        &mut pending_update.review_text,
    )
    .await;

    pending_update.scroll_offset = None;
}

/// Collects session-specific values used by `handle()` from the active view
/// row.
fn view_session_snapshot(app: &App, view_context: &ViewContext) -> Option<ViewSessionSnapshot> {
    let session = app.sessions.session_at(view_context.session_index)?;
    let session_status = session.status;
    let can_open_worktree = is_view_worktree_open_allowed(session_status)
        && *app
            .sessions
            .session_worktree_availability()
            .get(view_context.session_id.as_str())
            .unwrap_or(&false);

    Some(ViewSessionSnapshot {
        can_continue_terminal_session: session.allows_terminal_continuation(),
        can_open_worktree,
        can_start_staged_session: session.can_start_staged_session(),
        follow_up_task_action: app.selected_follow_up_task_action(&view_context.session_id),
        publish_pull_request_action: session.publish_pull_request_action(),
        session_state: help_action::session_view_state(session),
        session_status,
    })
}

/// Applies in-place updates for active view review status/text and scroll
/// position.
fn apply_view_scroll_and_output_mode(
    app: &mut App,
    review_status_message: Option<String>,
    review_text: Option<String>,
    scroll_offset: Option<u16>,
) {
    if let AppMode::View {
        review_status_message: view_review_status_message,
        review_text: view_review_text,
        scroll_offset: view_scroll_offset,
        ..
    } = &mut app.mode
    {
        *view_review_status_message = review_status_message;
        *view_review_text = review_text;
        *view_scroll_offset = scroll_offset;
    }
}

/// Returns whether `o` can access the session worktree.
fn is_view_worktree_open_allowed(status: Status) -> bool {
    !matches!(
        status,
        Status::Done
            | Status::Canceled
            | Status::InProgress
            | Status::Rebasing
            | Status::Merging
            | Status::Queued
    )
}

/// Returns whether non-navigation view shortcuts are available.
///
/// This covers `m` and the `/` slash-command shortcut.
fn is_view_action_allowed(status: Status) -> bool {
    !matches!(
        status,
        Status::Done
            | Status::InProgress
            | Status::Rebasing
            | Status::Merging
            | Status::Queued
            | Status::Canceled
    )
}

/// Returns whether `Enter` can open the chat composer.
///
/// Allowing `Enter` during `InProgress` lets users queue follow-up chat
/// messages without waiting for the running turn to return to `Review`.
/// Slash-command shortcuts and other action keys still require
/// [`is_view_action_allowed`] so terminal or rebasing sessions are not
/// accidentally re-driven.
fn is_view_chat_allowed(status: Status) -> bool {
    is_view_action_allowed(status) || matches!(status, Status::InProgress)
}

/// Returns whether the `d` shortcut can open the diff view.
fn is_view_diff_allowed(status: Status) -> bool {
    status.allows_review_actions()
}

/// Returns whether the `f` shortcut can open review content.
fn is_view_review_allowed(status: Status) -> bool {
    status.allows_review_actions()
}

/// Returns whether the `r` shortcut can start a session rebase from view
/// mode.
fn is_view_rebase_allowed(status: Status) -> bool {
    is_view_action_allowed(status) && status != Status::AgentReview
}

/// Handles `Ctrl+C` while a session is `InProgress` with a per-press policy.
///
/// Each press first tries to retract the most recently queued chat message on
/// [`SessionHandles::queued_messages`] (LIFO `pop_back`) so the user can undo
/// queue entries one-by-one in the reverse order they were added, without
/// interrupting the running turn. The running turn keeps streaming, status
/// stays `InProgress`, and no cancellation token, database status update, or
/// auto-review suppression runs while a queued message is being dropped.
/// When the queue is already empty, the press falls through to
/// [`cancel_in_progress_turn`] which performs the existing
/// cancel-and-return-to-`Review` flow.
async fn end_in_progress_turn(app: &mut App, session_id: &str) {
    if pop_last_queued_chat_message_if_any(app, session_id).await {
        return;
    }

    cancel_in_progress_turn(app, session_id).await;
}

/// Pops the most recently queued chat message (LIFO) from the session's
/// handles and re-syncs the snapshot from the post-pop handle state,
/// returning `true` when one queued message was retracted.
///
/// Pops the entry from the shared [`SessionHandles::queued_messages`] deque
/// via `pop_back`. The handle is the source of truth: the worker may have
/// already drained the oldest entry via `pop_front` between snapshot
/// refreshes, so a position-based snapshot pop could remove the wrong
/// transcript row and leave a phantom queued message visible. The snapshot
/// is then re-projected from the handle through
/// [`SessionState::sync_session_from_handle`], so no additional manual
/// `queued_messages` mutation is needed here. Releases any local image
/// attachments owned by the popped prompt through
/// [`App::cleanup_prompt_attachment_files`] so retracted messages do not
/// leak temp files under `AGENTTY_ROOT/tmp/`, then emits
/// [`AppEvent::SessionUpdated`] so list and chat views redraw without paying
/// for a full DB-backed `RefreshSessions` reload. Leaves the cancellation
/// token, persisted status, and auto-review suppression untouched so the
/// running turn can keep streaming.
async fn pop_last_queued_chat_message_if_any(app: &mut App, session_id: &str) -> bool {
    let popped_prompt = app
        .sessions
        .session_handles()
        .get(session_id)
        .and_then(|handles| handles.queued_messages.lock().ok()?.pop_back());

    let Some(popped_prompt) = popped_prompt else {
        return false;
    };

    app.sessions.sync_session_from_handle(session_id);

    app.cleanup_prompt_attachment_files(&popped_prompt).await;

    app.services.emit_app_event(AppEvent::SessionUpdated {
        session_id: session_id.into(),
        version: SessionTaskService::next_session_update_version(
            &app.services.session_update_versions(),
            session_id,
        ),
    });

    true
}

/// Interrupts the active turn of a running `InProgress` session and returns it
/// to `Review`.
///
/// Cancels queued operations in the database, then fires the per-turn
/// [`CancellationToken`] so the worker's `select!` branch triggers
/// graceful channel shutdown. The worker owns process termination:
/// CLI channels receive `SIGTERM` inside the cancellation branch
/// (where the child is guaranteed alive because `run_turn` has not
/// returned yet), and app-server channels shut down through
/// `shutdown_session`. Both paths converge on the worker returning a
/// `[Stopped]` error. After signalling, the persisted status is updated to
/// `Review`, the in-memory snapshot and shared handle are refreshed, and UI
/// events are emitted so the user can inspect or continue the session instead
/// of treating it as canceled.
async fn cancel_in_progress_turn(app: &mut App, session_id: &str) {
    let timestamp_seconds =
        app::session::unix_timestamp_from_system_time(app.services.clock().now_system_time());

    if let Err(error) = app
        .services
        .db()
        .operations()
        .request_cancel_for_session_operations(session_id)
        .await
    {
        warn!(
            session_id = session_id,
            error = %error,
            "failed to request cancellation for queued session operations"
        );
    }

    if let Some(handles) = app.sessions.session_handles().get(session_id) {
        // Cancel the current turn's token so the worker's `select!`
        // branch fires and triggers graceful channel shutdown. The
        // worker sends SIGTERM to CLI child processes inside the
        // cancellation path where the PID is guaranteed valid.
        match handles.cancel_token.lock() {
            Ok(cancel_token) => cancel_token.cancel(),
            Err(error) => {
                warn!(
                    session_id = session_id,
                    error = %error,
                    "failed to lock session cancel token"
                );
            }
        }
    }

    if let Err(error) = app
        .services
        .db()
        .sessions()
        .update_session_status_with_timing_at(
            session_id,
            &Status::Review.to_string(),
            timestamp_seconds,
        )
        .await
    {
        warn!(
            session_id = session_id,
            error = %error,
            "failed to persist review status after interrupting session turn"
        );

        return;
    }

    if let Some(handles) = app.sessions.session_handles().get(session_id)
        && let Ok(mut handle_status) = handles.status.lock()
    {
        *handle_status = Status::Review;
    }

    if let Some(session) = app
        .sessions
        .sessions_mut()
        .iter_mut()
        .find(|session| session.id == session_id)
    {
        session.status = Status::Review;
    }

    suppress_auto_review_for_stopped_turn(app, session_id);

    app.services.emit_app_event(AppEvent::SessionUpdated {
        session_id: session_id.into(),
        version: SessionTaskService::next_session_update_version(
            &app.services.session_update_versions(),
            session_id,
        ),
    });
    app.services.emit_session_and_project_refresh_events();
}

/// Marks automatic focused review as suppressed after a user stops one active
/// turn.
///
/// The session remains review-ready, but the reducer's automatic focused
/// review pass should not immediately start an agent review for the partially
/// stopped turn. The marker is intentionally inserted without loading a diff so
/// `Ctrl+C` returns to the event loop quickly; the next submitted turn clears
/// the cache, and pressing `f` still starts manual focused review because
/// view-mode review handling replaces suppressed entries.
fn suppress_auto_review_for_stopped_turn(app: &mut App, session_id: &str) {
    app.review_cache.insert(
        SessionId::from(session_id),
        ReviewCacheEntry::Suppressed { diff_hash: 0 },
    );
}

/// Switches the TUI mode from session view to the prompt input.
///
/// Focused-review output/status is copied into prompt mode so canceling the
/// composer returns to the same session transcript state. The caller supplies
/// the initial composer buffer so session-view shortcuts like `/` can open the
/// prompt with prefilled slash-command text.
fn switch_view_to_prompt(
    app: &mut App,
    view_context: &ViewContext,
    history_state: PromptHistoryState,
    input: InputState,
    scroll_offset: Option<u16>,
) {
    app.mode = AppMode::Prompt {
        at_mention_state: None,
        attachment_state: PromptAttachmentState::default(),
        history_state,
        review_status_message: view_context.review_status_message.clone(),
        review_text: view_context.review_text.clone(),
        slash_state: app.prompt_slash_state(),
        session_id: view_context.session_id.clone(),
        input,
        scroll_offset,
    };
}

/// Opens the help overlay while preserving the currently viewed session state.
fn open_view_help_overlay(
    app: &mut App,
    view_context: &ViewContext,
    view_session_snapshot: &ViewSessionSnapshot,
) {
    app.mode = AppMode::Help {
        context: HelpContext::View {
            can_open_worktree: view_session_snapshot.can_open_worktree,
            review_status_message: view_context.review_status_message.clone(),
            review_text: view_context.review_text.clone(),
            publish_pull_request_action: view_session_snapshot.publish_pull_request_action,
            session_id: view_context.session_id.clone(),
            session_state: view_session_snapshot.session_state,
            scroll_offset: view_context.scroll_offset,
        },
        scroll_offset: 0,
    };
}

/// Opens the session-view publish popup and preserves the current view state
/// for cancel or submit.
fn open_publish_branch_input(
    app: &mut App,
    view_context: &ViewContext,
    publish_branch_action: PublishBranchAction,
) {
    let Some(session) = app.sessions.session_at(view_context.session_index) else {
        return;
    };
    let default_branch_name = crate::app::session::session_branch(&session.id);
    let locked_upstream_ref = session.published_upstream_ref.clone();
    let input = locked_upstream_ref
        .as_deref()
        .map(remote_branch_name_from_upstream_ref)
        .map(InputState::with_text)
        .unwrap_or_default();

    app.mode = AppMode::PublishBranchInput {
        default_branch_name,
        input,
        locked_upstream_ref,
        publish_branch_action,
        restore_view: confirmation_view_mode(view_context),
    };
}

fn view_context(app: &mut App) -> Option<ViewContext> {
    let (review_status_message, review_text, session_id, scroll_offset) = match &app.mode {
        AppMode::View {
            review_status_message,
            review_text,
            session_id,
            scroll_offset,
        } => (
            review_status_message.clone(),
            review_text.clone(),
            session_id.clone(),
            *scroll_offset,
        ),
        _ => return None,
    };

    let Some(session_index) = app.session_index_for_id(&session_id) else {
        app.mode = AppMode::List;

        return None;
    };

    Some(ViewContext {
        review_status_message,
        review_text,
        scroll_offset,
        session_id,
        session_index,
    })
}

fn view_metrics<B: Backend>(
    app: &App,
    terminal: &Terminal<B>,
    view_context: &ViewContext,
) -> io::Result<ViewMetrics>
where
    B::Error: std::error::Error + Send + Sync + 'static,
{
    let terminal_size = terminal.size().map_err(crate::runtime::backend_err)?;
    let view_height = terminal_size.height.saturating_sub(5);
    let output_width = terminal_size.width.saturating_sub(2);
    let total_lines = view_total_lines(
        app,
        &view_context.session_id,
        view_context.session_index,
        view_context.review_status_message.as_deref(),
        view_context.review_text.as_deref(),
        output_width,
    );

    Ok(ViewMetrics {
        total_lines,
        view_height,
    })
}

fn view_total_lines(
    app: &App,
    session_id: &str,
    session_index: usize,
    review_status_message: Option<&str>,
    review_text: Option<&str>,
    output_width: u16,
) -> u16 {
    let active_progress = app.session_progress_message(session_id);
    let active_prompt_output = app
        .sessions
        .active_prompt_outputs()
        .get(session_id)
        .map(std::string::String::as_str);

    app.sessions.session_at(session_index).map_or(0, |session| {
        SessionChatPage::rendered_output_line_count(
            session,
            output_width,
            SessionOutputLineContext {
                active_prompt_output,
                active_progress,
                review_model: app.settings.default_review_model,
                review_status_message,
                review_text,
                session_update_version: app.session_update_version(session_id),
            },
            app.markdown_render_cache(),
            app.session_output_layout_cache(),
        )
    })
}

/// Extracts user prompt history entries from persisted session output text.
///
/// The parser accepts both legacy multiline prompts (raw continuation lines)
/// and the current continuation-prefixed format where follow-up lines start
/// with three spaces.
fn prompt_history_entries(output: &str) -> Vec<String> {
    let mut entries = Vec::new();
    let mut output_lines = output.lines().peekable();

    while let Some(line) = output_lines.next() {
        let Some(first_prompt_line) = line.strip_prefix(" › ") else {
            continue;
        };

        let mut prompt = first_prompt_line.to_string();

        while let Some(next_line) = output_lines.peek().copied() {
            if next_line.is_empty() {
                break;
            }

            let prompt_line = next_line.strip_prefix("   ").unwrap_or(next_line);
            prompt.push('\n');
            prompt.push_str(prompt_line);
            // Advance past the consumed continuation line.
            let _ = output_lines.next();
        }

        entries.push(prompt);
    }

    entries
}

/// Returns prompt-history entries for the session-view prompt composer.
///
/// Draft sessions use the staged prompt stored in `prompt` directly because
/// they have not yet written user prompts into the persisted transcript.
fn session_prompt_history_entries(session: &crate::domain::session::Session) -> Vec<String> {
    if session.status == Status::Draft && session.is_draft_session() {
        return vec![session.prompt.clone()];
    }

    prompt_history_entries(&session.output)
}

fn scroll_offset_down(scroll_offset: Option<u16>, metrics: ViewMetrics, step: u16) -> Option<u16> {
    let current_offset = scroll_offset?;

    let next_offset = current_offset.saturating_add(step.max(1));
    if next_offset >= metrics.total_lines.saturating_sub(metrics.view_height) {
        return None;
    }

    Some(next_offset)
}

fn scroll_offset_up(scroll_offset: Option<u16>, metrics: ViewMetrics, step: u16) -> u16 {
    let current_offset =
        scroll_offset.unwrap_or_else(|| metrics.total_lines.saturating_sub(metrics.view_height));

    current_offset.saturating_sub(step.max(1))
}

/// Computes the next scroll offset for half-page downward navigation.
fn scroll_offset_half_page_down(scroll_offset: Option<u16>, metrics: ViewMetrics) -> Option<u16> {
    scroll_offset_down(scroll_offset, metrics, half_page_scroll_step(metrics))
}

/// Computes the next scroll offset for half-page upward navigation.
fn scroll_offset_half_page_up(scroll_offset: Option<u16>, metrics: ViewMetrics) -> u16 {
    scroll_offset_up(scroll_offset, metrics, half_page_scroll_step(metrics))
}

/// Returns the number of lines used for half-page scroll shortcuts.
fn half_page_scroll_step(metrics: ViewMetrics) -> u16 {
    metrics.view_height / 2
}

/// Opens review mode and serves cached review or loading status.
///
/// Reviews are auto-generated when sessions transition to `Review`. When the
/// user presses `f` and no cached review exists yet, Agentty computes the
/// current diff, starts background generation, and shows a loading message
/// immediately. The resulting review is appended into the normal session
/// output panel instead of replacing it, and successful review text is
/// persisted for restart hydration.
async fn open_review_output_mode(
    app: &mut App,
    view_context: &ViewContext,
    review_status_message: &mut Option<String>,
    review_text: &mut Option<String>,
) {
    let review_is_loading = review_status_message
        .as_deref()
        .is_some_and(is_review_loading_status_message);
    if review_text.is_some() || review_is_loading {
        return;
    }

    if let Some(cached) = app.review_cache.get(view_context.session_id.as_str()) {
        match cached {
            ReviewCacheEntry::Loading { .. } => {
                let review_model = review_assist_model(app);
                *review_status_message = Some(review_loading_message(review_model));
                *review_text = None;
            }
            ReviewCacheEntry::Ready { text, .. } => {
                *review_status_message = None;
                *review_text = Some(text.clone());
            }
            ReviewCacheEntry::Failed { error, .. } => {
                *review_status_message =
                    Some(format!("Review assist unavailable: {}", error.trim()));
                *review_text = None;
            }
            ReviewCacheEntry::Suppressed { .. } => {}
        }

        if !matches!(cached, ReviewCacheEntry::Suppressed { .. }) {
            return;
        }
    }

    let Some(session) = app.sessions.session_at(view_context.session_index) else {
        *review_status_message = None;
        *review_text = Some(String::new());

        return;
    };
    let session_folder = session.folder.clone();
    let session_summary = session.summary.clone();
    let diff = load_view_session_diff(app, view_context).await;
    if diff.trim().is_empty() {
        *review_status_message = None;
        *review_text = Some(REVIEW_NO_DIFF_MESSAGE.to_string());

        return;
    }

    if diff.starts_with("Failed to run git diff:") {
        *review_status_message = None;
        *review_text = Some(diff);

        return;
    }

    let diff_hash = diff_content_hash(&diff);
    let review_model = review_assist_model(app);
    app.review_cache.insert(
        view_context.session_id.clone(),
        ReviewCacheEntry::Loading { diff_hash },
    );
    let _ = app
        .services
        .db()
        .sessions()
        .update_session_focused_review(&view_context.session_id, None, None)
        .await;
    *review_status_message = Some(review_loading_message(review_model));
    *review_text = None;
    app.start_review_assist(
        &view_context.session_id,
        &session_folder,
        diff_hash,
        &diff,
        session_summary.as_deref(),
    );
}

/// Opens diff mode only when the viewed session has actual worktree changes.
///
/// Returns `true` when diff mode was opened and `false` when the session diff
/// is empty, which keeps the view page in place so the `d` shortcut behaves as
/// unavailable for unchanged review sessions.
async fn show_diff_for_view_session(app: &mut App, view_context: &ViewContext) -> bool {
    let diff = load_view_session_diff(app, view_context).await;
    if diff.trim().is_empty() {
        return false;
    }

    app.mode = AppMode::Diff {
        diff,
        file_explorer_selected_index: 0,
        restore_question: None,
        right_panel: DiffRightPanel::Diff,
        scroll_cache: None,
        session_id: view_context.session_id.clone(),
        scroll_offset: 0,
    };

    true
}

/// Returns the configured model used for review assist generation.
fn review_assist_model(app: &App) -> AgentModel {
    app.settings.default_review_model
}

/// Loads the session worktree diff against its base branch.
async fn load_view_session_diff(app: &App, view_context: &ViewContext) -> String {
    let Some(session) = app.sessions.session_at(view_context.session_index) else {
        return String::new();
    };

    let session_folder = session.folder.clone();
    let base_branch = session.base_branch.clone();

    match app
        .services
        .git_client()
        .diff(session_folder, base_branch)
        .await
    {
        Ok(diff) => diff,
        Err(error) => {
            warn!(
                session_id = %view_context.session_id,
                error = %error,
                "failed to load session diff for view mode"
            );

            format!("Failed to run git diff: {error}")
        }
    }
}

async fn rebase_view_session(app: &mut App, session_id: &str) {
    if let Err(error) = app.rebase_session(session_id).await {
        app.append_output_for_session(session_id, &TranscriptNotice::RebaseError.format(error))
            .await;
    }
}

#[cfg(test)]
mod tests {
    use std::path::Path;
    use std::process::Command;
    use std::sync::Arc;

    use crossterm::event::KeyModifiers;
    use mockall::predicate::eq;
    use tempfile::tempdir;

    use super::*;
    use crate::app::AppClients;
    use crate::db::Database;
    use crate::infra::app_server;
    use crate::infra::tmux::{MockTmuxClient, TmuxClient};

    /// Returns a mock app-server client wrapped in `Arc` for test injection.
    fn mock_app_server() -> std::sync::Arc<dyn app_server::AppServerClient> {
        std::sync::Arc::new(app_server::MockAppServerClient::new())
    }

    /// Builds one client bundle with deterministic agent availability for
    /// test app startup.
    fn test_app_clients() -> AppClients {
        AppClients::new().with_agent_availability_probe(Arc::new(
            crate::infra::agent::StaticAgentAvailabilityProbe {
                available_agent_kinds: crate::domain::agent::AgentKind::ALL.to_vec(),
            },
        ))
    }

    /// Builds one test app with an injected tmux boundary.
    async fn new_test_app_with_tmux_client(
        tmux_client: Arc<dyn TmuxClient>,
    ) -> (App, tempfile::TempDir) {
        let base_dir = tempdir().expect("failed to create temp dir");
        let base_path = base_dir.path().to_path_buf();
        let database = Database::open_in_memory()
            .await
            .expect("failed to open in-memory db");
        let clients = test_app_clients()
            .with_app_server_client_override(mock_app_server())
            .with_tmux_client(tmux_client);
        let app = App::new_with_clients(base_path.clone(), base_path, None, database, clients)
            .await
            .expect("failed to build app");

        (app, base_dir)
    }

    /// Builds one test app with a strict mocked tmux boundary.
    async fn new_test_app() -> (App, tempfile::TempDir) {
        new_test_app_with_tmux_client(Arc::new(MockTmuxClient::new())).await
    }

    fn setup_test_git_repo(path: &Path) {
        Command::new("git")
            .args(["init"])
            .current_dir(path)
            .output()
            .expect("git init failed");
        Command::new("git")
            .args(["config", "user.name", "Test"])
            .current_dir(path)
            .output()
            .expect("git config failed");
        Command::new("git")
            .args(["config", "user.email", "test@test.com"])
            .current_dir(path)
            .output()
            .expect("git config failed");
        std::fs::write(path.join("README.md"), "test").expect("write failed");
        Command::new("git")
            .args(["add", "."])
            .current_dir(path)
            .output()
            .expect("git add failed");
        Command::new("git")
            .args(["commit", "-m", "Initial commit"])
            .current_dir(path)
            .output()
            .expect("git commit failed");
        Command::new("git")
            .args(["branch", "-M", "main"])
            .current_dir(path)
            .output()
            .expect("git branch failed");
    }

    /// Builds one git-backed test app with an injected tmux boundary.
    async fn new_test_app_with_git_and_tmux_client(
        tmux_client: Arc<dyn TmuxClient>,
    ) -> (App, tempfile::TempDir) {
        let base_dir = tempdir().expect("failed to create temp dir");
        let base_path = base_dir.path().to_path_buf();
        setup_test_git_repo(base_dir.path());
        let database = Database::open_in_memory()
            .await
            .expect("failed to open in-memory db");
        let clients = test_app_clients()
            .with_app_server_client_override(mock_app_server())
            .with_tmux_client(tmux_client);
        let app = App::new_with_clients(
            base_path.clone(),
            base_path,
            Some("main".to_string()),
            database,
            clients,
        )
        .await
        .expect("failed to build app");

        (app, base_dir)
    }

    /// Builds one git-backed test app with one created session and an
    /// injected tmux boundary.
    async fn new_test_app_with_session_and_tmux_client(
        tmux_client: Arc<dyn TmuxClient>,
    ) -> (App, tempfile::TempDir, String) {
        let (mut app, base_dir) = new_test_app_with_git_and_tmux_client(tmux_client).await;
        let session_id = app
            .create_session()
            .await
            .expect("failed to create session");

        (app, base_dir, session_id)
    }

    /// Builds one git-backed test app with one created session and a strict
    /// mocked tmux boundary.
    async fn new_test_app_with_session() -> (App, tempfile::TempDir, String) {
        new_test_app_with_session_and_tmux_client(Arc::new(MockTmuxClient::new())).await
    }

    /// Builds one minimal session snapshot for pure view-state tests.
    fn session_fixture(status: Status, is_draft: bool) -> crate::domain::session::Session {
        crate::domain::session::tests::SessionFixtureBuilder::new()
            .status(status)
            .draft(is_draft)
            .folder(std::env::temp_dir())
            .project_name("")
            .build()
    }

    #[test]
    fn test_is_view_worktree_open_allowed_returns_false_for_canceled() {
        // Arrange
        let status = Status::Canceled;

        // Act
        let can_open = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!can_open);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_returns_false_for_in_progress() {
        // Arrange
        let status = Status::InProgress;

        // Act
        let can_open = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!can_open);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_returns_false_for_rebasing() {
        // Arrange
        let status = Status::Rebasing;

        // Act
        let can_open = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!can_open);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_returns_false_for_merge_queue_statuses() {
        // Arrange
        let merge_queue_statuses = [Status::Queued, Status::Merging];

        // Act
        let can_open_for_statuses: Vec<bool> = merge_queue_statuses
            .iter()
            .map(|status| is_view_worktree_open_allowed(*status))
            .collect();

        // Assert
        assert!(can_open_for_statuses.iter().all(|can_open| !can_open));
    }

    #[test]
    fn test_is_view_action_allowed_only_for_non_done_non_in_progress_status() {
        // Arrange
        let canceled_status = Status::Canceled;
        let review_status = Status::Review;
        let in_progress_status = Status::InProgress;
        let done_status = Status::Done;

        // Act
        let canceled_allowed = is_view_action_allowed(canceled_status);
        let review_allowed = is_view_action_allowed(review_status);
        let in_progress_allowed = is_view_action_allowed(in_progress_status);
        let done_allowed = is_view_action_allowed(done_status);

        // Assert
        assert!(!canceled_allowed);
        assert!(review_allowed);
        assert!(!in_progress_allowed);
        assert!(!done_allowed);
    }

    #[test]
    fn test_is_view_diff_allowed_only_for_review_status() {
        // Arrange
        let review_status = Status::Review;
        let new_status = Status::Draft;
        let in_progress_status = Status::InProgress;

        // Act
        let review_allowed = is_view_diff_allowed(review_status);
        let new_allowed = is_view_diff_allowed(new_status);
        let in_progress_allowed = is_view_diff_allowed(in_progress_status);

        // Assert
        assert!(review_allowed);
        assert!(!new_allowed);
        assert!(!in_progress_allowed);
    }

    #[test]
    fn test_is_view_review_allowed_only_for_review_status() {
        // Arrange
        let review_status = Status::Review;
        let agent_review_status = Status::AgentReview;
        let done_status = Status::Done;
        let in_progress_status = Status::InProgress;

        // Act
        let review_allowed = is_view_review_allowed(review_status);
        let agent_review_allowed = is_view_review_allowed(agent_review_status);
        let done_allowed = is_view_review_allowed(done_status);
        let in_progress_allowed = is_view_review_allowed(in_progress_status);

        // Assert
        assert!(review_allowed);
        assert!(agent_review_allowed);
        assert!(!done_allowed);
        assert!(!in_progress_allowed);
    }

    #[test]
    fn test_is_view_rebase_allowed_blocks_agent_review() {
        // Arrange
        let review_status = Status::Review;
        let agent_review_status = Status::AgentReview;

        // Act
        let review_allowed = is_view_rebase_allowed(review_status);
        let agent_review_allowed = is_view_rebase_allowed(agent_review_status);

        // Assert
        assert!(review_allowed);
        assert!(!agent_review_allowed);
    }

    #[tokio::test]
    async fn test_view_context_returns_none_for_non_view_mode() {
        // Arrange
        let (mut app, _base_dir) = new_test_app().await;
        app.mode = AppMode::List;

        // Act
        let context = view_context(&mut app);

        // Assert
        assert!(context.is_none());
        assert!(matches!(app.mode, AppMode::List));
    }

    #[tokio::test]
    async fn test_view_context_falls_back_to_list_when_session_is_missing() {
        // Arrange
        let (mut app, _base_dir) = new_test_app().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: "missing-session".into(),
            scroll_offset: Some(2),
        };

        // Act
        let context = view_context(&mut app);

        // Assert
        assert!(context.is_none());
        assert!(matches!(app.mode, AppMode::List));
    }

    #[tokio::test]
    async fn test_view_context_returns_existing_session_details() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(4),
        };

        // Act
        let context = view_context(&mut app);

        // Assert
        assert!(context.is_some());
        let context = context.expect("expected view context");
        assert_eq!(context.session_id, session_id);
        assert_eq!(context.scroll_offset, Some(4));
        assert_eq!(context.session_index, 0);
    }

    #[tokio::test]
    async fn test_view_session_snapshot_disables_actions_for_done_session() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::Done;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        let snapshot = view_session_snapshot(&app, &context).expect("expected view snapshot");

        // Assert
        assert!(snapshot.can_continue_terminal_session);
        assert!(!snapshot.can_open_worktree);
        assert_eq!(snapshot.session_state, ViewSessionState::Done);
        assert_eq!(snapshot.session_status, Status::Done);
    }

    #[tokio::test]
    async fn test_view_session_snapshot_disables_continue_for_canceled_session() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::Canceled;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        let snapshot = view_session_snapshot(&app, &context).expect("expected view snapshot");

        // Assert
        assert!(!snapshot.can_continue_terminal_session);
        assert!(!snapshot.can_open_worktree);
        assert_eq!(snapshot.session_state, ViewSessionState::Canceled);
        assert_eq!(snapshot.session_status, Status::Canceled);
    }

    #[tokio::test]
    async fn test_view_session_snapshot_hides_worktree_open_for_unstarted_draft_session() {
        // Arrange
        let (mut app, _base_dir) =
            new_test_app_with_git_and_tmux_client(Arc::new(MockTmuxClient::new())).await;
        let session_id = app
            .create_draft_session()
            .await
            .expect("failed to create draft session");
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        let snapshot = view_session_snapshot(&app, &context).expect("expected view snapshot");

        // Assert
        assert!(!snapshot.can_open_worktree);
        assert_eq!(snapshot.session_state, ViewSessionState::NewSession);
    }

    #[tokio::test]
    async fn test_view_session_snapshot_hides_workflow_actions_for_stacked_draft() {
        // Arrange
        let (mut app, _base_dir) =
            new_test_app_with_git_and_tmux_client(Arc::new(MockTmuxClient::new())).await;
        let session_id = app
            .create_draft_session()
            .await
            .expect("failed to create draft session");
        let session = app
            .sessions
            .sessions_mut()
            .iter_mut()
            .find(|session| session.id == session_id)
            .expect("expected draft session");
        session.parent_session_id = Some("parent-session".into());
        session.prompt = "staged child draft".to_string();
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        let snapshot = view_session_snapshot(&app, &context).expect("expected view snapshot");

        // Assert
        assert_eq!(snapshot.session_state, ViewSessionState::StackedDraft);
        assert!(!snapshot.can_start_staged_session);
        assert!(!snapshot.can_merge_session());
        assert!(!snapshot.can_rebase_session());
    }

    #[tokio::test]
    async fn test_view_session_snapshot_reads_cached_worktree_availability() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions
            .set_session_worktree_available(&session_id, false);
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        let snapshot = view_session_snapshot(&app, &context).expect("expected view snapshot");

        // Assert
        assert!(!snapshot.can_open_worktree);
    }

    #[tokio::test]
    async fn test_view_session_snapshot_returns_none_for_stale_session_index() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(1),
        };
        let mut context = view_context(&mut app).expect("expected view context");
        context.session_index = 99;

        // Act
        let snapshot = view_session_snapshot(&app, &context);

        // Assert
        assert!(snapshot.is_none());
    }

    #[tokio::test]
    async fn test_view_total_lines_counts_wrapped_output_lines() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].output = "word ".repeat(40);
        let raw_line_count =
            u16::try_from(app.sessions.sessions()[0].output.lines().count()).unwrap_or(u16::MAX);

        // Act
        let total_lines = view_total_lines(&app, &session_id, 0, None, None, 20);

        // Assert
        assert!(total_lines > raw_line_count);
    }

    #[test]
    fn test_prompt_history_entries_extracts_user_prompts() {
        // Arrange
        let output = " › first\n\nassistant\n\n › second\n\n";

        // Act
        let entries = prompt_history_entries(output);

        // Assert
        assert_eq!(entries, vec!["first".to_string(), "second".to_string()]);
    }

    #[test]
    fn test_prompt_history_entries_keeps_multiline_prompts() {
        // Arrange
        let output = " › first line\n   second line\n\nassistant\n\n";

        // Act
        let entries = prompt_history_entries(output);

        // Assert
        assert_eq!(entries, vec!["first line\nsecond line".to_string()]);
    }

    #[test]
    fn test_prompt_history_entries_keeps_multiple_blank_lines_in_prompts() {
        // Arrange
        let output = " › first line\n   \n   \n   after gap\n\nassistant\n\n";

        // Act
        let entries = prompt_history_entries(output);

        // Assert
        assert_eq!(entries, vec!["first line\n\n\nafter gap".to_string()]);
    }

    #[test]
    fn test_prompt_history_entries_ignores_non_prompt_lines() {
        // Arrange
        let output = "assistant line\n\n";

        // Act
        let entries = prompt_history_entries(output);

        // Assert
        assert!(entries.is_empty());
    }

    #[tokio::test]
    async fn test_scroll_offset_down_does_not_jump_to_bottom_for_wrapped_output() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].output = "word ".repeat(60);
        let metrics = ViewMetrics {
            total_lines: view_total_lines(&app, &session_id, 0, None, None, 20),
            view_height: 5,
        };

        // Act
        let next_offset = scroll_offset_down(Some(0), metrics, 1);

        // Assert
        assert_eq!(next_offset, Some(1));
    }

    #[test]
    fn test_scroll_offset_down_returns_none_at_end_of_content() {
        // Arrange
        let metrics = ViewMetrics {
            total_lines: 20,
            view_height: 10,
        };

        // Act
        let next_offset = scroll_offset_down(Some(9), metrics, 1);

        // Assert
        assert_eq!(next_offset, None);
    }

    #[test]
    fn test_scroll_offset_up_uses_bottom_when_scroll_is_unset() {
        // Arrange
        let metrics = ViewMetrics {
            total_lines: 30,
            view_height: 10,
        };

        // Act
        let next_offset = scroll_offset_up(None, metrics, 5);

        // Assert
        assert_eq!(next_offset, 15);
    }

    #[tokio::test]
    async fn test_apply_view_scroll_and_output_mode_updates_review_state() {
        // Arrange
        let (mut app, _base_dir, expected_session_id) = new_test_app_with_session().await;
        let expected_status_message = review_loading_message(AgentModel::Gpt55);
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: expected_session_id.clone().into(),
            scroll_offset: Some(3),
        };

        // Act
        apply_view_scroll_and_output_mode(
            &mut app,
            Some(expected_status_message.clone()),
            None,
            Some(1),
        );

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::View {
                review_status_message: Some(ref actual_status_message),
                review_text: None,
                ref session_id,
                scroll_offset: Some(1),
            } if session_id == &expected_session_id
                && actual_status_message == &expected_status_message
        ));
    }

    #[test]
    fn test_is_review_loading_status_message_matches_model_aware_message() {
        // Arrange
        let status_message = review_loading_message(AgentModel::ClaudeOpus48);

        // Act
        let is_loading = is_review_loading_status_message(&status_message);

        // Assert
        assert!(is_loading);
    }

    #[test]
    fn test_is_review_loading_status_message_rejects_unrelated_message() {
        // Arrange
        let status_message = "Review complete.";

        // Act
        let is_loading = is_review_loading_status_message(status_message);

        // Assert
        assert!(!is_loading);
    }

    #[tokio::test]
    async fn test_review_assist_model_returns_default_review_model_setting() {
        // Arrange
        let (mut app, _base_dir, _session_id) = new_test_app_with_session().await;
        app.settings.default_review_model = AgentModel::ClaudeOpus48;

        // Act
        let review_model = review_assist_model(&app);

        // Assert
        assert_eq!(review_model, AgentModel::ClaudeOpus48);
    }

    #[tokio::test]
    async fn test_view_total_lines_uses_default_review_model_for_loading_fallback() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.settings.default_review_model = AgentModel::ClaudeHaiku4520251001;
        app.sessions.sessions_mut()[0].model = AgentModel::Gpt55;
        app.sessions.sessions_mut()[0].status = Status::AgentReview;
        let output_width = 14;
        let session = &app.sessions.sessions()[0];
        let expected = SessionChatPage::rendered_output_line_count(
            session,
            output_width,
            SessionOutputLineContext {
                active_prompt_output: None,
                active_progress: None,
                review_model: AgentModel::ClaudeHaiku4520251001,
                review_status_message: None,
                review_text: None,
                session_update_version: app.session_update_version(&session_id),
            },
            app.markdown_render_cache(),
            app.session_output_layout_cache(),
        );

        // Act
        let total_lines = view_total_lines(&app, &session_id, 0, None, None, output_width);

        // Assert
        assert_eq!(total_lines, expected);
    }

    #[tokio::test]
    async fn test_open_review_output_mode_reuses_cached_review_text() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut next_review_status_message = None;
        let mut next_review_text = Some("Cached review".to_string());

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(next_review_status_message, None);
        assert_eq!(next_review_text.as_deref(), Some("Cached review"));
    }

    #[tokio::test]
    async fn test_open_review_output_mode_starts_loading_when_diff_exists() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.settings.default_review_model = AgentModel::ClaudeOpus48;
        app.sessions.sessions_mut()[0].status = Status::Review;
        let session_folder = app.sessions.sessions()[0].folder.clone();
        std::fs::write(session_folder.join("README.md"), "review test content\n")
            .expect("failed to update readme");
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut next_review_status_message = None;
        let mut next_review_text = None;

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(
            next_review_status_message,
            Some(review_loading_message(AgentModel::ClaudeOpus48))
        );
        assert_eq!(next_review_text, None);
        assert_eq!(app.sessions.sessions()[0].status, Status::AgentReview);
        assert!(matches!(
            app.review_cache.get(&view_context.session_id),
            Some(ReviewCacheEntry::Loading { .. })
        ));
    }

    #[tokio::test]
    async fn test_open_review_output_mode_shows_no_diff_message_when_diff_empty() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut next_review_status_message = None;
        let mut next_review_text = None;

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(next_review_status_message, None);
        assert_eq!(next_review_text.as_deref(), Some(REVIEW_NO_DIFF_MESSAGE));
        assert!(!app.review_cache.contains_key(&view_context.session_id));
    }

    #[tokio::test]
    async fn test_open_review_output_mode_clears_stale_session_selection() {
        // Arrange
        let (app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 99,
        };
        let mut app = app;
        let mut next_review_status_message = None;
        let mut next_review_text = None;

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(next_review_status_message, None);
        assert_eq!(next_review_text, Some(String::new()));
    }

    #[tokio::test]
    async fn test_show_diff_for_view_session_switches_mode_to_diff() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let session_folder = app.sessions.sessions()[0].folder.clone();
        std::fs::write(session_folder.join("README.md"), "updated content")
            .expect("failed to write diff fixture");
        let context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(0),
            session_id: session_id.clone().into(),
            session_index: 0,
        };

        // Act
        let opened = show_diff_for_view_session(&mut app, &context).await;

        // Assert
        assert!(opened);
        assert!(matches!(
            app.mode,
            AppMode::Diff {
                ref session_id,
            scroll_offset: 0,
                ..
            } if session_id == &context.session_id
        ));
    }

    #[tokio::test]
    async fn test_show_diff_for_view_session_keeps_view_mode_when_diff_is_empty() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(0),
        };
        let context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(0),
            session_id: session_id.clone().into(),
            session_index: 0,
        };

        // Act
        let opened = show_diff_for_view_session(&mut app, &context).await;

        // Assert
        assert!(!opened);
        assert!(matches!(
            app.mode,
            AppMode::View {
                ref session_id,
            scroll_offset: Some(0),
                ..
            } if session_id == &context.session_id
        ));
    }

    #[tokio::test]
    async fn test_show_diff_for_view_session_uses_error_message_outside_git_repo() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let non_git_dir = tempdir().expect("failed to create non-git dir");
        app.sessions.sessions_mut()[0].folder = non_git_dir.path().to_path_buf();
        let context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(0),
            session_id: session_id.clone().into(),
            session_index: 0,
        };

        // Act
        let opened = show_diff_for_view_session(&mut app, &context).await;

        // Assert
        assert!(opened);
        assert!(matches!(
            app.mode,
            AppMode::Diff {
                ref session_id,
                ref diff,
                scroll_offset: 0,
                ..
            } if session_id == &context.session_id && diff.contains("Failed to run git diff:")
        ));
    }

    /// Verifies diff loading returns an empty string when the viewed session
    /// disappears before diff generation starts.
    #[tokio::test]
    async fn test_load_view_session_diff_returns_empty_string_for_stale_session_index() {
        // Arrange
        let (app, _base_dir, session_id) = new_test_app_with_session().await;
        let context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(0),
            session_id: session_id.into(),
            session_index: 99,
        };

        // Act
        let diff = load_view_session_diff(&app, &context).await;

        // Assert
        assert!(diff.is_empty());
    }

    #[tokio::test]
    async fn test_append_output_for_session_appends_text() {
        // Arrange
        let (app, _base_dir, session_id) = new_test_app_with_session().await;
        let mut app = app;

        // Act
        app.append_output_for_session(&session_id, "line one").await;

        // Assert
        app.sessions.sync_from_handles();
        let output = app.sessions.sessions()[0].output.clone();
        assert_eq!(output, "line one");
    }

    #[tokio::test]
    async fn test_open_merge_confirmation_sets_confirmation_mode_with_view_restore_state() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: Some(review_loading_message(AgentModel::Gpt55)),
            review_text: Some("Critical finding".to_string()),
            session_id: session_id.clone().into(),
            scroll_offset: Some(5),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        open_merge_confirmation(&mut app, &context);

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::Confirmation {
                confirmation_intent: ConfirmationIntent::MergeSession,
                ref confirmation_message,
                ref confirmation_title,
                restore_view: Some(ConfirmationViewMode {
                    review_status_message: Some(ref status_message),
                    review_text: Some(ref review_text),
                    scroll_offset: Some(5),
                    session_id: ref restored_session_id,
                }),
                session_id: Some(ref mode_session_id),
                selected_confirmation_index: DEFAULT_OPTION_INDEX,
            } if confirmation_title == "Confirm Merge"
                && confirmation_message == "Add this session to merge queue?"
                && restored_session_id == &session_id
                && mode_session_id == &session_id
                && status_message == &review_loading_message(AgentModel::Gpt55)
                && review_text == "Critical finding"
        ));
    }

    #[tokio::test]
    async fn test_open_worktree_for_view_session_opens_command_selector_for_multiple_commands() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.settings.open_command = "cargo test\nnpm run dev".to_string();
        app.mode = AppMode::View {
            review_status_message: Some(review_loading_message(AgentModel::Gpt55)),
            review_text: Some("Critical finding".to_string()),
            session_id: session_id.clone().into(),
            scroll_offset: Some(4),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        open_worktree_for_view_session(&mut app, &context).await;

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::OpenCommandSelector {
                ref commands,
                restore_view:
                    ConfirmationViewMode {
                        review_status_message: Some(ref status_message),
                        review_text: Some(ref review_text),
                        session_id: ref restored_session_id,
            scroll_offset: Some(4),
                    },
                selected_command_index: 0,
            } if commands == &vec!["cargo test".to_string(), "npm run dev".to_string()]
                && restored_session_id == &session_id
                && status_message == &review_loading_message(AgentModel::Gpt55)
                && review_text == "Critical finding"
        ));
    }

    #[tokio::test]
    async fn test_open_worktree_for_view_session_keeps_view_mode_for_single_command() {
        // Arrange
        let mut mock_tmux_client = MockTmuxClient::new();
        mock_tmux_client
            .expect_open_window_for_folder()
            .times(1)
            .returning(|_| Box::pin(async { Some("@42".to_string()) }));
        mock_tmux_client
            .expect_run_command_in_window()
            .with(eq("@42".to_string()), eq("cargo test".to_string()))
            .times(1)
            .returning(|_, _| Box::pin(async {}));
        let (mut app, _base_dir, session_id) =
            new_test_app_with_session_and_tmux_client(Arc::new(mock_tmux_client)).await;
        app.settings.open_command = "cargo test".to_string();
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let context = view_context(&mut app).expect("expected view context");

        // Act
        open_worktree_for_view_session(&mut app, &context).await;

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::View {
                review_status_message: None,
                review_text: None,
                session_id: ref mode_session_id,
            scroll_offset: Some(2),
            } if mode_session_id == &session_id
        ));
    }

    #[tokio::test]
    async fn test_rebase_view_session_appends_error_output_without_review_status() {
        // Arrange
        let (app, _base_dir, session_id) = new_test_app_with_session().await;
        let mut app = app;

        // Act
        rebase_view_session(&mut app, &session_id).await;

        // Assert
        app.sessions.sync_from_handles();
        let output = app.sessions.sessions()[0].output.clone();
        assert!(output.contains("[Rebase Error]"));
    }

    #[tokio::test]
    async fn test_open_view_help_overlay_preserves_view_context() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: Some(review_loading_message(AgentModel::Gpt55)),
            review_text: Some("Critical finding".to_string()),
            scroll_offset: Some(3),
            session_id: session_id.clone().into(),
            session_index: 0,
        };
        let view_session_snapshot = ViewSessionSnapshot {
            can_continue_terminal_session: false,
            can_open_worktree: true,
            can_start_staged_session: false,
            follow_up_task_action: None,
            publish_pull_request_action: Some(PublishBranchAction::PublishPullRequest),
            session_state: ViewSessionState::Review,
            session_status: Status::Review,
        };

        // Act
        open_view_help_overlay(&mut app, &view_context, &view_session_snapshot);

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::Help {
                context: HelpContext::View {
                    can_open_worktree: true,
                    review_status_message: Some(ref status_message),
                    review_text: Some(ref review_text),
                    publish_pull_request_action: Some(PublishBranchAction::PublishPullRequest),
                    session_id: ref session_id_in_mode,
                    session_state: ViewSessionState::Review,
                    scroll_offset: Some(3),
                    ..
                },
                scroll_offset: 0,
            } if session_id_in_mode == &session_id
                && status_message == &review_loading_message(AgentModel::Gpt55)
                && review_text == "Critical finding"
        ));
    }

    #[tokio::test]
    async fn test_open_publish_branch_input_preserves_view_context() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: Some(review_loading_message(AgentModel::Gpt55)),
            review_text: Some("Critical finding".to_string()),
            scroll_offset: Some(5),
            session_id: session_id.clone().into(),
            session_index: 0,
        };

        // Act
        open_publish_branch_input(
            &mut app,
            &view_context,
            PublishBranchAction::PublishPullRequest,
        );

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::PublishBranchInput {
                ref default_branch_name,
                input: ref input_state,
                locked_upstream_ref: None,
                publish_branch_action: PublishBranchAction::PublishPullRequest,
                restore_view:
                    ConfirmationViewMode {
                        review_status_message: Some(ref status_message),
                        review_text: Some(ref review_text),
                        session_id: ref restored_session_id,
            scroll_offset: Some(5),
                    },
            } if default_branch_name == &crate::app::session::session_branch(&session_id)
                && input_state.cursor == 0
                && input_state.text().is_empty()
                && restored_session_id == &session_id
                && status_message == &review_loading_message(AgentModel::Gpt55)
                && review_text == "Critical finding"
        ));
    }

    #[tokio::test]
    async fn test_open_publish_branch_input_locks_existing_upstream_branch_name() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].published_upstream_ref =
            Some("origin/review/custom".to_string());
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(1),
            session_id: session_id.into(),
            session_index: 0,
        };

        // Act
        open_publish_branch_input(
            &mut app,
            &view_context,
            PublishBranchAction::PublishPullRequest,
        );

        // Assert
        assert!(matches!(
            app.mode,
            AppMode::PublishBranchInput {
                input: ref input_state,
                locked_upstream_ref: Some(ref upstream_ref),
                ..
            } if upstream_ref == "origin/review/custom"
                && input_state.text() == "review/custom"
        ));
    }

    #[test]
    fn test_is_view_worktree_open_allowed_disables_canceled_state() {
        // Arrange
        let status = Status::Canceled;

        // Act
        let result = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!result);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_disables_done_state() {
        // Arrange
        let status = Status::Done;

        // Act
        let result = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!result);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_disables_queued_state() {
        // Arrange
        let status = Status::Queued;

        // Act
        let result = is_view_worktree_open_allowed(status);

        // Assert
        assert!(!result);
    }

    #[test]
    fn test_is_view_worktree_open_allowed_enables_review_state() {
        // Arrange
        let status = Status::Review;

        // Act
        let result = is_view_worktree_open_allowed(status);

        // Assert
        assert!(result);
    }

    #[test]
    fn test_view_session_state_maps_merge_queue_statuses() {
        // Arrange
        let merge_queue_statuses = [Status::Queued, Status::Merging];

        // Act
        let mapped_states: Vec<ViewSessionState> = merge_queue_statuses
            .iter()
            .map(|status| help_action::session_view_state(&session_fixture(*status, false)))
            .collect();

        // Assert
        assert!(
            mapped_states
                .iter()
                .all(|state| *state == ViewSessionState::MergeQueue)
        );
    }

    #[test]
    fn test_view_session_state_maps_rebasing_status() {
        // Arrange
        let status = Status::Rebasing;
        let session = session_fixture(status, false);

        // Act
        let state = help_action::session_view_state(&session);

        // Assert
        assert_eq!(state, ViewSessionState::Rebasing);
    }

    #[test]
    fn test_view_session_state_maps_stacked_draft_status() {
        // Arrange
        let session = crate::domain::session::tests::SessionFixtureBuilder::new()
            .status(Status::Draft)
            .draft(true)
            .parent_session_id(Some("parent-session".into()))
            .folder(std::env::temp_dir())
            .project_name("")
            .build();

        // Act
        let state = help_action::session_view_state(&session);

        // Assert
        assert_eq!(state, ViewSessionState::StackedDraft);
    }

    #[test]
    fn test_view_session_state_maps_canceled_status() {
        // Arrange
        let status = Status::Canceled;
        let session = session_fixture(status, false);

        // Act
        let state = help_action::session_view_state(&session);

        // Assert
        assert_eq!(state, ViewSessionState::Canceled);
    }
    #[tokio::test]
    async fn test_open_review_output_mode_uses_ready_cache_entry() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let cached_text = "## Review\nCached review from auto-generation.";
        app.review_cache.insert(
            session_id.clone().into(),
            ReviewCacheEntry::Ready {
                diff_hash: 123,
                text: cached_text.to_string(),
            },
        );
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut next_review_status_message = None;
        let mut next_review_text = None;

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(next_review_status_message, None);
        assert_eq!(next_review_text.as_deref(), Some(cached_text));
    }

    #[tokio::test]
    async fn test_open_review_output_mode_shows_loading_for_cache_loading_entry() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.settings.default_review_model = AgentModel::ClaudeOpus48;
        app.review_cache.insert(
            session_id.clone().into(),
            ReviewCacheEntry::Loading { diff_hash: 456 },
        );
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: None,
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut next_review_status_message = None;
        let mut next_review_text = None;

        // Act
        open_review_output_mode(
            &mut app,
            &view_context,
            &mut next_review_status_message,
            &mut next_review_text,
        )
        .await;

        // Assert
        assert_eq!(
            next_review_status_message,
            Some(review_loading_message(AgentModel::ClaudeOpus48))
        );
        assert_eq!(next_review_text, None);
    }

    #[tokio::test]
    async fn test_open_or_regenerate_review_opens_when_review_output_is_missing() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: None,
            review_text: None,
            scroll_offset: Some(5),
            session_id: session_id.into(),
            session_index: 0,
        };
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);

        // Act
        open_or_regenerate_review(&mut app, &view_context, &mut pending_update).await;

        // Assert
        assert_eq!(pending_update.scroll_offset, None);
    }

    #[tokio::test]
    async fn test_open_or_regenerate_shows_confirmation_when_review_output_exists() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.review_cache.insert(
            session_id.clone().into(),
            ReviewCacheEntry::Ready {
                text: "Old review".to_string(),
                diff_hash: 123,
            },
        );
        let view_context = ViewContext {
            review_status_message: None,
            review_text: Some("Old review".to_string()),
            scroll_offset: None,
            session_id: session_id.clone().into(),
            session_index: 0,
        };
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);

        // Act
        open_or_regenerate_review(&mut app, &view_context, &mut pending_update).await;

        // Assert — confirmation popup is shown instead of direct regeneration
        assert!(matches!(
            app.mode,
            AppMode::Confirmation {
                confirmation_intent: ConfirmationIntent::RegenerateReview,
                ..
            }
        ));
        // Cache is preserved until user confirms
        assert!(app.review_cache.contains_key(session_id.as_str()));
    }

    #[tokio::test]
    async fn test_open_or_regenerate_skips_when_loading_in_progress() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.review_cache.insert(
            session_id.clone().into(),
            ReviewCacheEntry::Loading { diff_hash: 42 },
        );
        let loading_message = review_loading_message(app.settings.default_review_model);
        let view_context = ViewContext {
            review_status_message: Some(loading_message.clone()),
            review_text: None,
            scroll_offset: None,
            session_id: session_id.clone().into(),
            session_index: 0,
        };
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);

        // Act
        open_or_regenerate_review(&mut app, &view_context, &mut pending_update).await;

        // Assert — cache and loading state are preserved, no duplicate spawned
        assert!(matches!(
            app.review_cache.get(session_id.as_str()),
            Some(ReviewCacheEntry::Loading { diff_hash: 42 })
        ));
        assert_eq!(pending_update.review_status_message, Some(loading_message));
    }

    #[tokio::test]
    async fn test_handle_view_key_ignores_diff_for_non_review_status() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let view_context = view_context(&mut app).expect("expected view context");
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);
        let view_session_snapshot = ViewSessionSnapshot {
            can_continue_terminal_session: false,
            can_open_worktree: false,
            can_start_staged_session: false,
            follow_up_task_action: None,
            publish_pull_request_action: None,
            session_state: ViewSessionState::Done,
            session_status: Status::Done,
        };
        let view_key_context = ViewKeyContext {
            context: &view_context,
            metrics: ViewMetrics {
                total_lines: 10,
                view_height: 5,
            },
            session_snapshot: &view_session_snapshot,
        };

        // Act
        let should_apply = handle_view_key(
            &mut app,
            KeyEvent::new(KeyCode::Char('d'), KeyModifiers::NONE),
            view_key_context,
            &mut pending_update,
        )
        .await;

        // Assert
        assert!(should_apply);
        assert!(matches!(
            app.mode,
            AppMode::View {
                ref session_id,
            scroll_offset: Some(2),
                ..
            } if session_id == &view_context.session_id
        ));
        assert_eq!(pending_update.scroll_offset, Some(2));
    }

    #[tokio::test]
    async fn test_handle_launch_follow_up_task_key_opens_linked_sibling_session() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let sibling_session_id = app
            .create_session()
            .await
            .expect("failed to create sibling session");
        let source_session = app
            .sessions
            .sessions_mut()
            .iter_mut()
            .find(|session| session.id == session_id)
            .expect("expected source session in session list");
        source_session.follow_up_tasks = vec![crate::domain::session::SessionFollowUpTask {
            id: 1,
            launched_session_id: Some(sibling_session_id.clone().into()),
            position: 0,
            text: "Open the sibling session.".to_string(),
        }];
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.into(),
            scroll_offset: Some(0),
        };
        let backend = ratatui::backend::TestBackend::new(120, 30);
        let mut terminal = ratatui::Terminal::new(backend).expect("failed to create terminal");

        // Act
        let result = handle(
            &mut app,
            &mut terminal,
            KeyEvent::new(KeyCode::Char('l'), KeyModifiers::NONE),
        )
        .await
        .expect("launch/open key should be handled");

        // Assert
        assert!(matches!(result, EventResult::Continue));
        assert_eq!(
            app.selected_session().map(|session| session.id.as_str()),
            Some(sibling_session_id.as_str())
        );
        assert!(matches!(
            app.mode,
            AppMode::View {
                ref session_id,
                ..
            } if session_id == &sibling_session_id
        ));
    }

    #[tokio::test]
    async fn test_handle_continue_key_opens_confirmation_for_done_session() {
        // Arrange
        let (mut app, _base_dir, source_session_id) = new_test_app_with_session().await;
        let source_session = app
            .sessions
            .sessions_mut()
            .iter_mut()
            .find(|session| session.id == source_session_id)
            .expect("expected source session in session list");
        source_session.status = Status::Done;
        source_session.summary = Some("# Summary\n\nKeep going.".to_string());
        source_session.title = Some("Done source".to_string());
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: source_session_id.clone().into(),
            scroll_offset: Some(0),
        };
        let backend = ratatui::backend::TestBackend::new(120, 30);
        let mut terminal = ratatui::Terminal::new(backend).expect("failed to create terminal");

        // Act
        let result = handle(
            &mut app,
            &mut terminal,
            KeyEvent::new(KeyCode::Char('c'), KeyModifiers::NONE),
        )
        .await
        .expect("continue key should be handled");

        // Assert
        assert!(matches!(result, EventResult::Continue));
        assert!(matches!(
            app.mode,
            AppMode::Confirmation {
                confirmation_intent: ConfirmationIntent::ContinueSession,
                ref confirmation_title,
                ref confirmation_message,
                ref restore_view,
                ref session_id,
                ..
            } if confirmation_title == "Confirm Continue"
                && confirmation_message
                    == "Create a new draft session with initial context from this session?"
                && matches!(restore_view, Some(restore_view) if restore_view.session_id == source_session_id)
                && matches!(session_id, Some(session_id) if session_id.as_str() == source_session_id)
        ));
    }

    #[tokio::test]
    async fn test_handle_continue_key_does_not_open_confirmation_for_canceled_session() {
        // Arrange
        let (mut app, _base_dir, source_session_id) = new_test_app_with_session().await;
        app.sessions
            .sessions_mut()
            .iter_mut()
            .find(|session| session.id == source_session_id)
            .expect("expected source session")
            .status = Status::Canceled;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: source_session_id.clone().into(),
            scroll_offset: Some(0),
        };
        let backend = ratatui::backend::TestBackend::new(120, 30);
        let mut terminal = ratatui::Terminal::new(backend).expect("failed to create terminal");

        // Act
        let result = handle(
            &mut app,
            &mut terminal,
            KeyEvent::new(KeyCode::Char('c'), KeyModifiers::NONE),
        )
        .await
        .expect("c key should be handled");

        // Assert
        assert!(matches!(result, EventResult::Continue));
        assert!(matches!(
            app.mode,
            AppMode::View {
                ref session_id,
                ..
            } if session_id.as_str() == source_session_id
        ));
    }

    #[tokio::test]
    async fn test_handle_view_key_slash_opens_prompt_with_prefilled_slash() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: Some("Review loading".to_string()),
            review_text: Some("Focused review".to_string()),
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let view_context = view_context(&mut app).expect("expected view context");
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);
        let view_session_snapshot = ViewSessionSnapshot {
            can_continue_terminal_session: false,
            can_open_worktree: true,
            can_start_staged_session: false,
            follow_up_task_action: None,
            publish_pull_request_action: None,
            session_state: ViewSessionState::Review,
            session_status: Status::Review,
        };
        let view_key_context = ViewKeyContext {
            context: &view_context,
            metrics: ViewMetrics {
                total_lines: 10,
                view_height: 5,
            },
            session_snapshot: &view_session_snapshot,
        };

        // Act
        let should_apply = handle_view_key(
            &mut app,
            KeyEvent::new(KeyCode::Char('/'), KeyModifiers::NONE),
            view_key_context,
            &mut pending_update,
        )
        .await;

        // Assert
        assert!(should_apply);
        assert!(matches!(
            app.mode,
            AppMode::Prompt {
                ref input,
                ref review_status_message,
                ref review_text,
                ref session_id,
            scroll_offset: Some(2),
                ..
            } if input.text() == "/"
                && input.cursor == 1
                && review_status_message.as_deref() == Some("Review loading")
                && review_text.as_deref() == Some("Focused review")
                && session_id == &view_context.session_id
        ));
    }

    #[tokio::test]
    async fn test_handle_view_key_p_opens_review_request_publish_input() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let view_context = view_context(&mut app).expect("expected view context");
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);
        let view_session_snapshot = ViewSessionSnapshot {
            can_continue_terminal_session: false,
            can_open_worktree: true,
            can_start_staged_session: false,
            follow_up_task_action: None,
            publish_pull_request_action: Some(PublishBranchAction::PublishPullRequest),
            session_state: ViewSessionState::Review,
            session_status: Status::Review,
        };
        let view_key_context = ViewKeyContext {
            context: &view_context,
            metrics: ViewMetrics {
                total_lines: 10,
                view_height: 5,
            },
            session_snapshot: &view_session_snapshot,
        };

        // Act
        let should_apply = handle_view_key(
            &mut app,
            KeyEvent::new(KeyCode::Char('p'), KeyModifiers::NONE),
            view_key_context,
            &mut pending_update,
        )
        .await;

        // Assert
        assert!(!should_apply);
        assert!(matches!(
            app.mode,
            AppMode::PublishBranchInput {
                publish_branch_action: PublishBranchAction::PublishPullRequest,
                ref restore_view,
                ..
            } if restore_view.session_id == session_id
        ));
    }

    #[tokio::test]
    async fn test_handle_view_key_shift_p_opens_review_request_publish_input() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let view_context = view_context(&mut app).expect("expected view context");
        let mut pending_update = ViewPendingUpdate::from_context(&view_context);
        let view_session_snapshot = ViewSessionSnapshot {
            can_continue_terminal_session: false,
            can_open_worktree: true,
            can_start_staged_session: false,
            follow_up_task_action: None,
            publish_pull_request_action: Some(PublishBranchAction::PublishPullRequest),
            session_state: ViewSessionState::Review,
            session_status: Status::Review,
        };
        let view_key_context = ViewKeyContext {
            context: &view_context,
            metrics: ViewMetrics {
                total_lines: 10,
                view_height: 5,
            },
            session_snapshot: &view_session_snapshot,
        };

        // Act
        let should_apply = handle_view_key(
            &mut app,
            KeyEvent::new(KeyCode::Char('P'), KeyModifiers::SHIFT),
            view_key_context,
            &mut pending_update,
        )
        .await;

        // Assert
        assert!(!should_apply);
        assert!(matches!(
            app.mode,
            AppMode::PublishBranchInput {
                publish_branch_action: PublishBranchAction::PublishPullRequest,
                ref restore_view,
                ..
            } if restore_view.session_id == session_id
        ));
    }

    /// Verifies session-view action keys are ignored when the current session
    /// status does not allow those actions.
    #[tokio::test]
    async fn test_handle_view_key_ignores_status_gated_actions() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.mode = AppMode::View {
            review_status_message: None,
            review_text: None,
            session_id: session_id.clone().into(),
            scroll_offset: Some(2),
        };
        let view_context = view_context(&mut app).expect("expected view context");
        let view_metrics = ViewMetrics {
            total_lines: 10,
            view_height: 5,
        };

        // Act
        for key in [
            KeyEvent::new(KeyCode::Char('o'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('/'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('m'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('r'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('f'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('p'), KeyModifiers::NONE),
            KeyEvent::new(KeyCode::Char('P'), KeyModifiers::SHIFT),
        ] {
            let mut pending_update = ViewPendingUpdate::from_context(&view_context);
            let view_session_snapshot = ViewSessionSnapshot {
                can_continue_terminal_session: false,
                can_open_worktree: false,
                can_start_staged_session: false,
                follow_up_task_action: None,
                publish_pull_request_action: None,
                session_state: ViewSessionState::Done,
                session_status: Status::Done,
            };
            let view_key_context = ViewKeyContext {
                context: &view_context,
                metrics: view_metrics,
                session_snapshot: &view_session_snapshot,
            };
            let should_apply =
                handle_view_key(&mut app, key, view_key_context, &mut pending_update).await;

            // Assert
            assert!(should_apply);
            assert!(matches!(
                app.mode,
                AppMode::View {
                    ref session_id,
            scroll_offset: Some(2),
                    ..
                } if session_id == &view_context.session_id
            ));
            assert_eq!(pending_update.scroll_offset, Some(2));
        }
    }

    #[tokio::test]
    async fn test_q_always_transitions_to_list() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        let view_context = ViewContext {
            review_status_message: None,
            review_text: Some("review text".to_string()),
            scroll_offset: Some(10),
            session_id: session_id.into(),
            session_index: 0,
        };
        let pending_update = ViewPendingUpdate::from_context(&view_context);

        // Act — q always returns to list without mutating pending review state.
        app.mode = AppMode::List;

        // Assert
        assert!(matches!(app.mode, AppMode::List));
        assert_eq!(pending_update.review_text.as_deref(), Some("review text"));
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_transitions_session_to_review() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        app.sessions.session_handles_mut().insert(
            session_id.clone().into(),
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress),
        );

        // Act
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert
        assert_eq!(app.sessions.sessions()[0].status, Status::Review);
        let handle_status = *app
            .sessions
            .session_handles()
            .get(session_id.as_str())
            .expect("handles missing")
            .status
            .lock()
            .expect("lock failed");
        assert_eq!(handle_status, Status::Review);
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_does_not_send_sigterm_directly() {
        // Arrange — spawn a child and store its PID in the handles.
        // SIGTERM is now sent by the worker's cancellation path, not
        // `end_in_progress_turn`, so the child should remain alive.
        let mut child = tokio::process::Command::new("sleep")
            .arg("60")
            .spawn()
            .expect("failed to spawn sleep");
        let child_pid = child.id().expect("child has no pid");

        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        if let Ok(mut guard) = handles.child_pid.lock() {
            *guard = Some(child_pid);
        }
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);

        // Act
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — child is still alive because the UI no longer sends
        // SIGTERM; the worker owns process termination.
        assert!(
            child.try_wait().expect("try_wait failed").is_none(),
            "child should still be running — UI must not send SIGTERM"
        );

        // Cleanup
        child.kill().await.expect("failed to kill child");
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_cancels_token() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        let cancel_token = std::sync::Arc::clone(&handles.cancel_token);
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);

        // Act
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — the token must be cancelled so the worker's `select!`
        // branch fires.
        let is_cancelled = cancel_token
            .lock()
            .expect("cancel token lock")
            .is_cancelled();
        assert!(
            is_cancelled,
            "cancel_token should be cancelled by end_in_progress_turn"
        );
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_keeps_review_session_review_ready() {
        // Arrange
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::Review;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::Review.to_string(), 0)
            .await;
        app.sessions.session_handles_mut().insert(
            session_id.clone().into(),
            crate::domain::session::SessionHandles::new(String::new(), Status::Review),
        );

        // Act
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert
        assert_eq!(app.sessions.sessions()[0].status, Status::Review);
        let handle_status = *app
            .sessions
            .session_handles()
            .get(session_id.as_str())
            .expect("handles missing")
            .status
            .lock()
            .expect("lock failed");
        assert_eq!(handle_status, Status::Review);
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_first_press_with_queue_pops_last_queued_message() {
        // Arrange — seed an InProgress session with two queued chat messages
        // so the LIFO pop is observable (the older entry must remain).
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        let cancel_token = std::sync::Arc::clone(&handles.cancel_token);
        let queued_messages = std::sync::Arc::clone(&handles.queued_messages);
        {
            let mut queued = queued_messages.lock().expect("queued_messages lock");
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from("first queued"));
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from(
                "second queued",
            ));
        }
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);
        app.sessions.sessions_mut()[0].queued_messages =
            vec!["first queued".to_string(), "second queued".to_string()];

        // Act — first Ctrl+C while the queue is non-empty.
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — the most recently queued message is popped (LIFO), the
        // older message remains, status stays InProgress, and the cancel
        // token is untouched so the running turn keeps streaming.
        let remaining_handle_queue: Vec<String> = queued_messages
            .lock()
            .expect("queued_messages lock")
            .iter()
            .map(crate::domain::turn_prompt::TurnPrompt::transcript_text)
            .collect();
        assert_eq!(
            remaining_handle_queue,
            vec!["first queued".to_string()],
            "only the most recently queued chat message should be popped on first Ctrl+C"
        );
        assert_eq!(
            app.sessions.sessions()[0].queued_messages,
            vec!["first queued".to_string()],
            "snapshot queued_messages should mirror the handle after LIFO pop"
        );
        assert_eq!(
            app.sessions.sessions()[0].status,
            Status::InProgress,
            "status should stay InProgress while only a queued message is popped"
        );
        let handle_status = *app
            .sessions
            .session_handles()
            .get(session_id.as_str())
            .expect("handles missing")
            .status
            .lock()
            .expect("lock failed");
        assert_eq!(handle_status, Status::InProgress);
        assert!(
            !cancel_token
                .lock()
                .expect("cancel token lock")
                .is_cancelled(),
            "cancel_token must not be cancelled when only a queued message is popped"
        );
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_drains_queue_one_press_at_a_time_then_cancels() {
        // Arrange — InProgress session with two queued chat messages so we
        // can observe LIFO drain across consecutive presses before falling
        // through to the cancel path.
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        let cancel_token = std::sync::Arc::clone(&handles.cancel_token);
        let queued_messages = std::sync::Arc::clone(&handles.queued_messages);
        {
            let mut queued = queued_messages.lock().expect("queued_messages lock");
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from("first queued"));
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from(
                "second queued",
            ));
        }
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);
        app.sessions.sessions_mut()[0].queued_messages =
            vec!["first queued".to_string(), "second queued".to_string()];

        // Act — first press pops "second queued".
        end_in_progress_turn(&mut app, &session_id).await;
        // Act — second press pops "first queued".
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — queue is empty after two presses, but the running turn
        // still has not been cancelled yet.
        assert!(
            queued_messages
                .lock()
                .expect("queued_messages lock")
                .is_empty(),
            "queue should be drained after one press per queued message"
        );
        assert!(
            app.sessions.sessions()[0].queued_messages.is_empty(),
            "snapshot queued_messages should be empty after LIFO drain"
        );
        assert_eq!(app.sessions.sessions()[0].status, Status::InProgress);
        assert!(
            !cancel_token
                .lock()
                .expect("cancel token lock")
                .is_cancelled(),
            "cancel_token must not be cancelled while queued messages are still being drained"
        );

        // Act — third press, with empty queue, falls through to cancel.
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — cancel path engages and the session returns to Review.
        assert!(
            cancel_token
                .lock()
                .expect("cancel token lock")
                .is_cancelled(),
            "cancel_token must be cancelled once the queue is drained"
        );
        assert_eq!(app.sessions.sessions()[0].status, Status::Review);
    }

    #[tokio::test]
    async fn test_end_in_progress_turn_second_press_after_empty_queue_cancels_turn() {
        // Arrange — InProgress session with an empty queue, mirroring the
        // state after the first press has already drained queued messages.
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        let cancel_token = std::sync::Arc::clone(&handles.cancel_token);
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);

        // Act — second Ctrl+C now that the queue is empty.
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — falls through to the cancel path: cancel token fires and
        // the session transitions to Review.
        assert!(
            cancel_token
                .lock()
                .expect("cancel token lock")
                .is_cancelled(),
            "cancel_token must be cancelled when the queue is empty"
        );
        assert_eq!(app.sessions.sessions()[0].status, Status::Review);
        let handle_status = *app
            .sessions
            .session_handles()
            .get(session_id.as_str())
            .expect("handles missing")
            .status
            .lock()
            .expect("lock failed");
        assert_eq!(handle_status, Status::Review);
    }

    #[tokio::test]
    /// Regression: when the worker has already drained the oldest queued
    /// prompt via `pop_front` but the deferred `RefreshSessions` reducer
    /// has not yet rebuilt the snapshot, a `Ctrl+C` press must still align
    /// the snapshot with the current handle state instead of removing the
    /// snapshot's last entry positionally and leaving a phantom queued row.
    async fn test_pop_last_queued_chat_message_resyncs_snapshot_after_worker_drain() {
        // Arrange — two prompts queued; simulate the worker popping the
        // oldest entry off the handle without yet refreshing the snapshot.
        let (mut app, _base_dir, session_id) = new_test_app_with_session().await;
        app.sessions.sessions_mut()[0].status = Status::InProgress;
        let _ = app
            .services
            .db()
            .sessions()
            .update_session_status_with_timing_at(&session_id, &Status::InProgress.to_string(), 0)
            .await;
        let handles =
            crate::domain::session::SessionHandles::new(String::new(), Status::InProgress);
        let queued_messages = std::sync::Arc::clone(&handles.queued_messages);
        {
            let mut queued = queued_messages.lock().expect("queued_messages lock");
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from("first queued"));
            queued.push_back(crate::domain::turn_prompt::TurnPrompt::from(
                "second queued",
            ));
        }
        app.sessions
            .session_handles_mut()
            .insert(session_id.clone().into(), handles);
        app.sessions.sessions_mut()[0].queued_messages =
            vec!["first queued".to_string(), "second queued".to_string()];

        // Simulate the worker `pop_front` draining the oldest entry before
        // the snapshot has been refreshed.
        {
            let mut queued = queued_messages.lock().expect("queued_messages lock");
            queued.pop_front();
        }

        // Act — Ctrl+C while the handle has [second] but the snapshot still
        // reads [first, second].
        end_in_progress_turn(&mut app, &session_id).await;

        // Assert — handle is now empty (the user retracted "second"), and
        // the snapshot reflects the post-pop handle state instead of
        // positionally dropping the snapshot's last entry (which would
        // leave a phantom "first queued" row pointing at a turn the worker
        // is already running).
        assert!(
            queued_messages
                .lock()
                .expect("queued_messages lock")
                .is_empty(),
            "handle queue should be empty after retracting the only remaining entry"
        );
        assert!(
            app.sessions.sessions()[0].queued_messages.is_empty(),
            "snapshot must rebuild from the handle state and not show a phantom row for a prompt \
             the worker is already executing"
        );
    }
}