cydonia 0.1.8

//! The projects sidebar: a folding heading per project, and every session,
//! article and table in it. The window's grid lives in [`crate::view::root`];
//! this draws on it.

use crate::{
    model::{session::ChatSession, settings::Features, update},
    view::{
        article::TogglePlainText,
        component::{
            menu::{self, Menu},
            transcript,
        },
        keymap::{self, Command},
        root::{self, CommitName, Cydonia, DismissName, NewSession, OpenProject, Pane},
        settings::Section,
    },
};
use bezel::ui::scroll as scrollbars;
use bezel::{
    agent::orbs::{OrbState, engine::Frame},
    gpui::{
        self, AnyElement, App, Bounds, Context, Div, Empty, Entity, Focusable as _, FontWeight,
        Hsla, MouseButton, Pixels, Point, ScrollStrategy, SharedString, Stateful,
        UniformListDecoration, Window, div, prelude::*, px, uniform_list,
    },
    theme::{TextStyle, Theme, Typeset},
    ui::{
        icons::{self, Icon},
        input::Case,
        menu::Item,
        popover,
        surface::Surfaced as _,
        tooltip::Tooltip,
        widgets::{Buttons, Content, Layout},
    },
};
use std::{cell::RefCell, cmp::Reverse, ops::Range, rc::Rc, time::Duration};

/// What the sidebar needs of a session to draw its row, read out of the model
/// before the row is built: a turn in flight puts a thinking orb in the mark's
/// place, and the orb leases the frame clock, which wants the app mutably.
struct SessionRow {
    project: usize,
    id: u64,
    label: String,
    icon: Option<Icon>,
    /// The turn in flight, as the orb needs it: which of the twelve, how long
    /// it has been running, and the buffer it paints into. `None` when nothing
    /// is in flight, which is what puts the agent's own mark back.
    working: Option<Working>,
    archived: bool,
}

/// A session's orb, read off the model with the row.
struct Working {
    state: OrbState,
    since: Duration,
    frame: Rc<RefCell<Frame>>,
}

/// One line of the sidebar. An address, not content: the label behind it is
/// read when the row is built, which [`uniform_list`] only does for the rows on
/// screen.
#[derive(Clone, Copy, PartialEq, Eq)]
pub(crate) enum Row {
    Project(usize),
    /// The line the archived entries are folded under.
    Archive(usize),
    Session {
        project: usize,
        id: u64,
    },
    Board {
        project: usize,
        ix: usize,
    },
    Article {
        project: usize,
        ix: usize,
    },
    Table {
        project: usize,
        ix: usize,
    },
}

/// Whether the kind a row names is switched on. Articles have no switch, and
/// neither do the two rows that are not entries — a project heading and the
/// line its archive folds under stand whatever is listed beneath them.
fn shown(row: Row, features: &Features) -> bool {
    match row {
        Row::Session { .. } => features.sessions,
        Row::Board { .. } => features.boards,
        Row::Table { .. } => features.tables,
        Row::Project(_) | Row::Archive(_) | Row::Article { .. } => true,
    }
}

/// What the sidebar's name field is attached to. One field for all of them,
/// because only one row can be being named at a time. Each entry is held by
/// what identifies it — a session, a table's key — never by an index: that
/// moves the moment a neighbour is made or dropped, and the field would follow
/// it onto whichever entry slid underneath.
///
/// No article here: its title is the first line of its own page, which is
/// where it is written — see [`crate::view::article`].
#[derive(Clone, PartialEq, Eq)]
pub(crate) enum Renaming {
    Session(u64),
    Table(String),
    /// A lane on the open board. The one entry here that no row in the sidebar
    /// stands for — the field is drawn in the column's own header instead,
    /// which works because only one thing is ever being named.
    Column(String),
}

/// What an entry's row is written in: the one on screen at full strength, one
/// put away a step back from the rest.
pub(crate) fn tint(selected: bool, archived: bool, theme: &Theme) -> Hsla {
    match (selected, archived) {
        (true, _) => theme.text,
        (false, true) => theme.text_faint,
        (false, false) => theme.text_muted,
    }
}

/// A project on its way to another place in the list. The index is safe to
/// carry: nothing reorders the list while a drag is in flight.
#[derive(Clone)]
pub(crate) struct ProjectDrag(usize);

/// What rides under the cursor while a project is being carried.
struct Carried(SharedString);

impl Render for Carried {
    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        let theme = Theme::of(cx).clone();
        popover::popover_card(&theme)
            .px(px(10.))
            .py(px(4.))
            .text_style(TextStyle::Callout)
            .text_color(theme.text)
            .child(self.0.clone())
    }
}

/// An entry's own name in the element tree: two rows must never share one.
fn key_of(entry: Row) -> String {
    match entry {
        Row::Project(ix) => format!("project-{ix}"),
        Row::Archive(ix) => format!("archive-{ix}"),
        Row::Session { project, id } => format!("session-{project}-{id}"),
        Row::Board { project, ix } => format!("board-{project}-{ix}"),
        Row::Article { project, ix } => format!("article-{project}-{ix}"),
        Row::Table { project, ix } => format!("table-{project}-{ix}"),
    }
}

/// The wash a row paints, and — with the 1px either side of it that used to be
/// the column's gap — the pitch the list lays every row out at. One height for
/// headings and rows alike, because [`uniform_list`] measures a single row and
/// gives every other one the same.
const ROW_PILL: f32 = 30.;
pub(crate) const ROW_HEIGHT: f32 = ROW_PILL + 2.;

/// How far the pinned heading's glass runs past the band it is seen in, and is
/// clipped away.
///
/// A lens bends what is behind it within [`bezel::theme::SurfaceSpec::rim`] of
/// its own edge, and lights the edge itself. On a bar one row tall that is the
/// whole of it: two bands and two hairlines, reading as a line ruled along the
/// top and the bottom. Run the glass out past the clip and only its middle —
/// the flat blur — is left in view.
const PINNED_BLEED: f32 = 20.;

/// Shared row styling keeps selection backgrounds full-width when indented.
pub(crate) fn row(
    id: impl Into<gpui::ElementId>,
    group: &'static str,
    selected: bool,
    indent: bool,
    theme: &Theme,
) -> Stateful<Div> {
    div()
        .id(id)
        .group(group)
        .h(px(ROW_PILL))
        .ml(px(root::SIDEBAR_GUTTER))
        .mr(px(root::SIDEBAR_GUTTER))
        .px(px(root::SIDEBAR_GUTTER))
        .when(indent, |el| el.pl(px(root::SIDEBAR_GUTTER + 14.)))
        .flex()
        .flex_row()
        .items_center()
        .gap(px(8.))
        .rounded(px(Theme::control_radius()))
        .cursor_pointer()
        .when(selected, |el| el.bg(theme.element_active))
        // Only off the open row: the hover wash is the weaker rung, and
        // painting it over the selection would dim what the pointer is on.
        .when(!selected, |el| el.hover(|el| el.bg(theme.element_hover)))
}

/// A row's name. The line height is what the field pins itself to: left to
/// gpui's default the label's box is φ×13, and renaming would resize the row
/// under the name being typed.
fn row_label(name: String, tint: Hsla) -> AnyElement {
    div()
        .flex_1()
        .min_w_0()
        .truncate()
        .text_style(TextStyle::Body)
        .line_height(px(18.))
        .text_color(tint)
        .child(name)
        .into_any_element()
}

/// The heading of the project whose entries are under the scroll, held at the
/// top of the list while they pass beneath it.
///
/// A decoration rather than a child of the column, because this is the one
/// place the scroll offset for the frame being drawn is known. Read off the
/// handle in `render` it would be the offset of the frame before, and the
/// heading would lag the rows it belongs to by one.
struct PinnedHead(Entity<Cydonia>);

impl UniformListDecoration for PinnedHead {
    fn compute(
        &self,
        visible: Range<usize>,
        _bounds: Bounds<Pixels>,
        scroll: Point<Pixels>,
        item_height: Pixels,
        _count: usize,
        _window: &mut Window,
        cx: &mut App,
    ) -> AnyElement {
        self.0.update(cx, |this, cx| {
            this.pinned_head(visible.start, scroll.y, item_height, cx)
        })
    }
}

impl Cydonia {
    fn sidebar_hover(&mut self, menu: Menu, hovered: bool, cx: &mut Context<Self>) {
        if hovered {
            if self.sidebar_hovered.as_ref() == Some(&menu) {
                return;
            }
            self.sidebar_hovered = Some(menu);
        } else if self.sidebar_hovered.as_ref() == Some(&menu) {
            self.sidebar_hovered = None;
        } else {
            return;
        }
        cx.notify();
    }

    pub(crate) fn sidebar(&self, cx: &mut Context<Self>) -> impl IntoElement + use<> {
        let theme = Theme::of(cx).clone();
        // Taken here, where the workspace is already open, because the two
        // tooltips below are built inside closures that outlive this borrow.
        let shortcuts = &self.workspace.read(cx).settings.shortcuts;
        let settings_chord = keymap::label(Command::OpenSettings, shortcuts);
        let open_chord = keymap::label(Command::OpenProject, shortcuts);
        let rows = self.rows(cx);
        let count = rows.len();
        div()
            .flex_none()
            .w(px(self.sidebar_width))
            .h_full()
            .bg(root::sidebar_bg(&theme))
            .flex()
            .flex_col()
            // The fold out at the trailing edge: the lights float in the
            // leading half of the strip, which is what leaves nothing there to
            // pad them clear of.
            .child(
                div()
                    .flex_none()
                    .h(px(root::HEADER_HEIGHT))
                    .pr(px(8.))
                    .flex()
                    .flex_row()
                    .items_center()
                    .justify_end()
                    .child(self.fold_toggle(theme.text_faint, cx)),
            )
            .child(
                div()
                    .relative()
                    .flex_1()
                    .min_h_0()
                    .child(
                        uniform_list(
                            "project-list",
                            count,
                            cx.processor(move |this, range: Range<usize>, _, cx| {
                                range.map(|ix| this.sidebar_row(rows[ix], cx)).collect()
                            }),
                        )
                        .track_scroll(&self.rail)
                        .with_decoration(PinnedHead(cx.entity()))
                        .size_full(),
                    )
                    .child(
                        scrollbars::Overlay::new(
                            "sidebar-bar",
                            &self.rail.0.borrow().base_handle,
                            bezel::gpui::Axis::Vertical,
                        )
                        .visibility(
                            self.workspace
                                .read(cx)
                                .settings
                                .appearance
                                .sidebar_scrollbars
                                .into(),
                        ),
                    ),
            )
            .children(self.restart_notice(cx))
            .child(
                div()
                    .flex_none()
                    .mx(px(8.))
                    .mb(px(8.))
                    .flex()
                    .flex_row()
                    .items_center()
                    .justify_between()
                    .child(
                        theme
                            .ghost("settings")
                            .px(px(8.))
                            .py(px(6.))
                            // The mark alone, like every other control on this
                            // line. What it opens is said in the tooltip, which
                            // is where the two beside it say theirs.
                            // The chord read off the table the keymap was
                            // built from rather than typed beside the label:
                            // it is the reader's to move, and a tooltip naming
                            // the one it used to be is a lie nothing catches.
                            .tooltip(move |window, cx| match settings_chord.clone() {
                                Some(chord) => {
                                    Tooltip::with_keystroke("Settings", chord, window, cx)
                                }
                                None => Tooltip::text("Settings", window, cx),
                            })
                            .child(
                                icons::icon(icons::account::Settings)
                                    .size(px(13.))
                                    .text_color(theme.text_faint),
                            )
                            .on_click(cx.listener(|this, _, _, cx| {
                                this.open_settings(Section::General, cx)
                            })),
                    )
                    .child(
                        div().flex().flex_row().items_center().gap(px(2.)).child(
                            theme
                                .ghost("open-project")
                                .px(px(8.))
                                .py(px(6.))
                                .tooltip(move |window, cx| match open_chord.clone() {
                                    Some(chord) => {
                                        Tooltip::with_keystroke("Open project", chord, window, cx)
                                    }
                                    None => Tooltip::text("Open project", window, cx),
                                })
                                .child(
                                    icons::icon(icons::files::FolderPlus)
                                        .size(px(13.))
                                        .text_color(theme.text_faint),
                                )
                                .on_click(cx.listener(|this, _, window, cx| {
                                    this.open_project_action(&OpenProject, window, cx);
                                })),
                        ),
                    ),
            )
    }

    /// The one place outside settings that says a release is in hand: a line at
    /// the foot of the sidebar, over the controls, that restarts into it.
    ///
    /// Here rather than in the header because it is news and not a control for
    /// what is on screen — and the foot of this column is already where the
    /// things that are about the app itself live. It takes a row rather than
    /// floating over one, so nothing it appears in front of is ever covered.
    ///
    /// Nothing shows here until a bundle is staged and verified, which on most
    /// days is never — see [`crate::model::update`], and the Developer section
    /// for the switch that puts it on screen without one.
    fn restart_notice(&self, cx: &mut Context<Self>) -> Option<impl IntoElement + use<>> {
        let updater = update::of(cx)?;
        let version = updater.read(cx).ready()?;
        let theme = Theme::of(cx).clone();
        let ready = SharedString::from(format!("cydonia {version} is ready"));
        Some(
            theme
                .ghost("restart-to-update")
                .flex_none()
                .mx(px(8.))
                .mb(px(8.))
                .px(px(8.))
                .py(px(6.))
                .gap(px(6.))
                // No plate under it: `ghost` paints one on hover, and anything
                // at rest would have to be quieter than that to leave the hover
                // anything to say. What gives the line its weight is the mark,
                // which is the only accent-coloured thing in the column.
                .tooltip(move |window, cx| Tooltip::text(ready.clone(), window, cx))
                .child(
                    icons::icon(icons::development::CircleFadingArrowUp)
                        .size(px(13.))
                        .flex_none()
                        .text_color(theme.accent),
                )
                .child(
                    div()
                        .flex_1()
                        .min_w_0()
                        .truncate()
                        .text_style(TextStyle::Footnote)
                        .child("Restart to update"),
                )
                .child(theme.badge(version))
                .on_click(cx.listener(move |_, _, _, cx| {
                    updater.update(cx, |updater, cx| updater.restart(cx));
                })),
        )
    }

    /// The control that folds the sidebar away and brings it back. It belongs
    /// to whichever column runs along the window's left edge, so it changes
    /// strip across the collapse — and takes that strip's tone with it.
    pub(crate) fn fold_toggle(
        &self,
        tint: Hsla,
        cx: &mut Context<Self>,
    ) -> impl IntoElement + use<> {
        let theme = Theme::of(cx).clone();
        let label = if self.sidebar_open {
            "Hide sidebar"
        } else {
            "Show sidebar"
        };
        theme
            .ghost("toggle-sidebar")
            .p(px(4.))
            .tooltip(move |window, cx| Tooltip::text(label, window, cx))
            .child(
                icons::icon(if self.sidebar_open {
                    icons::layout::PanelLeftClose
                } else {
                    icons::layout::PanelLeftOpen
                })
                .size(px(14.))
                .text_color(tint),
            )
            .on_click(cx.listener(|this, _, _, cx| this.toggle_sidebar(cx)))
    }

    /// The heading held at the top of the list, and where to hold it.
    ///
    /// Measured in the list's own space — the decoration is laid out over the
    /// whole run of rows, so `y` here is counted from the first of them rather
    /// than from the top of what is on screen.
    fn pinned_head(
        &self,
        first: usize,
        scroll: Pixels,
        item_height: Pixels,
        cx: &mut Context<Self>,
    ) -> AnyElement {
        let rows = self.rows(cx);
        let head = |row: &Row| matches!(row, Row::Project(_));
        let Some(at) = rows
            .get(..=first)
            .and_then(|above| above.iter().rposition(head))
        else {
            return Empty.into_any_element();
        };
        let Row::Project(ix) = rows[at] else {
            return Empty.into_any_element();
        };
        // The next heading pushes this one out rather than sliding under it,
        // which is what keeps two of them from ever reading as one block.
        let next = rows[at + 1..]
            .iter()
            .position(head)
            .map(|after| item_height * (at + 1 + after) - item_height);
        let rest = item_height * at;
        let y = next.map_or(-scroll, |limit| (-scroll).min(limit));
        // Above its own place there is nothing to hold: the row itself is on
        // screen, in the list, where it belongs.
        if y <= rest {
            return Empty.into_any_element();
        }
        div()
            .size_full()
            .relative()
            .child(
                // Stateful, and so an id scope of its own: the copy inside
                // carries the same ids as the row it stands for.
                //
                // The band the glass is seen in, and what clips it to one row.
                div()
                    .id("pinned-head")
                    .absolute()
                    .top(y)
                    .left_0()
                    .w_full()
                    .h(px(ROW_HEIGHT))
                    .overflow_hidden()
                    .child(self.project_head(ix, true, cx)),
            )
            .into_any_element()
    }

    /// One project's heading: it folds, and its `+` opens what can be made in
    /// the project.
    ///
    /// `pinned` is the copy [`Cydonia::pinned_head`] holds at the top of the
    /// list. It gives up the pill for the column's full width, and takes the
    /// glass the floating cluster below it is cut from — a heading with rows
    /// running under it has to be read against whatever is passing.
    fn project_head(&self, ix: usize, pinned: bool, cx: &mut Context<Self>) -> AnyElement {
        let theme = Theme::of(cx).clone();
        let (name, expanded) = match self.workspace.read(cx).projects.get(ix) {
            Some(project) => (project.name(), project.expanded),
            None => return Empty.into_any_element(),
        };
        let carried = SharedString::from(name.clone());
        let head = div()
            .id(("project", ix))
            .group("project-head")
            .on_hover(cx.listener(move |this, hovered: &bool, _, cx| {
                this.sidebar_hover(Menu::Add(ix), *hovered, cx);
            }))
            // Pinned it runs edge to edge, and past the band it shows in at
            // the top and the bottom — see [`PINNED_BLEED`]. The label keeps
            // the x the pill's own margin and padding put it at.
            .when(pinned, |el| {
                el.absolute()
                    .top(px(-PINNED_BLEED))
                    .left_0()
                    .right_0()
                    .h(px(ROW_HEIGHT + 2. * PINNED_BLEED))
                    .px(px(8. + 6.))
            })
            .when(!pinned, |el| {
                el.relative()
                    .mx(px(8.))
                    .px(px(6.))
                    .h(px(ROW_PILL))
                    .rounded(px(Theme::control_radius()))
            })
            .flex()
            .flex_row()
            .items_center()
            .gap(px(6.))
            .cursor_pointer()
            // On the head, not the label: a name's colour is fixed when
            // its text is laid out, and only this div is stateful enough
            // to carry the hover that far.
            .text_color(theme.text_faint)
            .hover(|el| el.text_color(theme.text))
            .child(
                theme
                    .ghost(("project-fold", ix))
                    .flex_none()
                    .p(px(2.))
                    .child(
                        icons::icon(match expanded {
                            true => icons::files::FolderOpen,
                            false => icons::files::Folder,
                        })
                        .size(px(14.))
                        .text_color(theme.text_faint)
                        .group_hover("project-head", |el| el.text_color(theme.text)),
                    )
                    .on_click(cx.listener(move |this, _, _, cx| {
                        cx.stop_propagation();
                        this.toggle_project(ix, cx);
                    })),
            )
            .child(
                div()
                    .flex_1()
                    .min_w_0()
                    .truncate()
                    .text_style(TextStyle::Callout)
                    .font_weight(FontWeight::MEDIUM)
                    .child(name),
            )
            .child(
                self.menu_button(
                    ("project-add", ix),
                    Some("project-head"),
                    icons::icon(icons::math::Plus)
                        .size(px(12.))
                        .text_color(theme.text_faint)
                        .group_hover("project-head", |el| el.text_color(theme.text)),
                    Menu::Add(ix),
                    cx,
                )
                .children(self.add_menu(ix, cx)),
            )
            .children(self.project_menu(ix, cx))
            .on_mouse_down(
                MouseButton::Right,
                cx.listener(move |this, _, _, cx| this.toggle_menu(Menu::Project(ix), cx)),
            )
            // A press on the copy is a press on where it came from: the list
            // goes back to the heading it is standing in for, rather than
            // folding away the project you are reading. Its own folder mark
            // still folds — that press stops before it reaches here.
            .on_click(cx.listener(move |this, _, _, cx| match pinned {
                true => this.scroll_to_project(ix, cx),
                false => this.toggle_project(ix, cx),
            }))
            // Carried by its heading, and dropped on the heading it is to sit
            // in front of. Nothing else in the column is draggable: what the
            // entries are ordered by is when they were last written.
            .on_drag(ProjectDrag(ix), move |_, _, _, cx| {
                let carried = carried.clone();
                cx.new(|_| Carried(carried))
            })
            .drag_over::<ProjectDrag>(move |style, _, _, cx| style.bg(Theme::of(cx).element_active))
            .on_drop(cx.listener(move |this, drag: &ProjectDrag, _, cx| {
                this.move_project(drag.0, ix, cx);
            }));
        // Its own menu opens on the press rather than the click, so the note
        // has to be here too — read stale, a right press would swallow.
        let head = self.menu_press(head, Menu::Project(ix), cx);
        match pinned {
            // The same token the cluster at the foot of the column mounts on,
            // so the two glasses in the sidebar move together.
            true => head
                .surface(&theme, theme.popover_surface)
                .into_any_element(),
            false => head.into_any_element(),
        }
    }

    /// Entries ordered by last user submission for sessions, last edit otherwise.
    ///
    /// One list rather than four: the kinds are told apart by their marks, and
    /// grouping by kind buries the table you are working in under every article
    /// you are not. Only the addresses are ordered — each kind's own list keeps
    /// the indices these carry.
    pub(crate) fn entries(&self, project: usize, cx: &App) -> Vec<Row> {
        let workspace = self.workspace.read(cx);
        let Some(open) = workspace.projects.get(project) else {
            return Vec::new();
        };
        let features = &workspace.settings.features;
        let sessions = open.sessions.iter().map(|chat| {
            (
                chat.closed,
                chat.touched(),
                Row::Session {
                    project,
                    id: chat.id,
                },
            )
        });
        let boards = open
            .boards
            .iter()
            .enumerate()
            .map(|(ix, board)| (board.archived, board.touched, Row::Board { project, ix }));
        let articles = open.articles.iter().enumerate().map(|(ix, article)| {
            (
                article.archived,
                article.touched,
                Row::Article { project, ix },
            )
        });
        // The store keeps seconds; every other stamp here is milliseconds.
        let tables = open.tables.iter().enumerate().map(|(ix, table)| {
            let at = table.updated_at.unwrap_or(table.created_at).max(0) as u128;
            (table.archived, at * 1000, Row::Table { project, ix })
        });
        let mut entries: Vec<(bool, u128, Row)> = sessions
            .chain(boards)
            .chain(articles)
            .chain(tables)
            .collect();
        // A project is read off disk whole whatever is switched on, so what a
        // switch hides it hides here — the entries stay in the project and in
        // memory, and turning it back on lists them again with nothing to
        // rescan.
        entries.retain(|(_, _, row)| shown(*row, features));
        // Archived entries sink; each half follows the entry's recency stamp.
        entries.sort_by_key(|(archived, touched, _)| (*archived, Reverse(*touched)));
        let split = entries.iter().position(|(archived, ..)| *archived);
        let mut rows: Vec<Row> = entries
            .iter()
            .take(split.unwrap_or(entries.len()))
            .map(|(_, _, row)| *row)
            .collect();
        if let Some(split) = split {
            rows.push(Row::Archive(project));
            if open.archive_open {
                rows.extend(entries[split..].iter().map(|(_, _, row)| *row));
            }
        }
        rows
    }

    /// Every line the sidebar shows, in order. Addresses only: a project with a
    /// thousand articles costs a thousand `Row`s here and reads a title for
    /// none of them.
    pub(crate) fn rows(&self, cx: &Context<Self>) -> Vec<Row> {
        let mut rows = Vec::new();
        for p in 0..self.workspace.read(cx).projects.len() {
            rows.push(Row::Project(p));
            if self.workspace.read(cx).projects[p].expanded {
                rows.extend(self.entries(p, cx));
            }
        }
        rows
    }

    /// Open what a row points at — what a keyboard step does with its landing.
    /// The pointer never comes through here: each row carries its own
    /// `on_click`, which needs no [`Row`] to know what it is.
    pub(crate) fn open_row(&mut self, row: Row, window: &mut Window, cx: &mut Context<Self>) {
        match row {
            Row::Project(ix) => self.select_project(ix, cx),
            Row::Archive(ix) => self.toggle_archive(ix, cx),
            Row::Session { id, .. } => self.select_session(id, cx),
            Row::Board { project, ix } => self.open_board(project, ix, cx),
            Row::Article { project, ix } => self.open_article(project, ix, window, cx),
            Row::Table { project, ix } => self.open_table(project, ix, cx),
        }
    }

    /// Take the list back to where a project starts, heading and all.
    fn scroll_to_project(&mut self, ix: usize, cx: &mut Context<Self>) {
        let Some(at) = self
            .rows(cx)
            .iter()
            .position(|row| *row == Row::Project(ix))
        else {
            return;
        };
        self.rail.scroll_to_item(at, ScrollStrategy::Top);
        cx.notify();
    }

    /// Scroll the rail to a row, if it is not already on screen. `Nearest`
    /// rather than `Top`: a step to the neighbour below should move the list by
    /// a row, not throw the one you came from off the top of it.
    pub(crate) fn reveal(&mut self, row: Row, cx: &Context<Self>) {
        if let Some(ix) = self.rows(cx).iter().position(|at| *at == row) {
            self.rail.scroll_to_item(ix, ScrollStrategy::Nearest);
        }
    }

    /// One line, built when the list scrolls it into view. The box around it is
    /// what holds the pitch: the row inside paints the wash, and the pixel
    /// either side of it is the gap between two.
    fn sidebar_row(&self, row: Row, cx: &mut Context<Self>) -> AnyElement {
        let workspace = self.workspace.read(cx);
        let inner = match row {
            Row::Project(ix) => self.project_head(ix, false, cx),
            Row::Archive(ix) => self.archive_divider(ix, cx),
            Row::Session { project, id } => match self.session_of(project, id, cx) {
                Some(session) => self.session_row(session, cx),
                None => Empty.into_any_element(),
            },
            Row::Board { project, ix } => {
                match workspace
                    .projects
                    .get(project)
                    .and_then(|open| open.boards.get(ix).map(|board| board.label().to_owned()))
                {
                    Some(name) => self.board_row(project, ix, name, cx),
                    None => Empty.into_any_element(),
                }
            }
            Row::Article { project, ix } => {
                match workspace.projects.get(project).and_then(|open| {
                    open.articles
                        .get(ix)
                        .map(|article| article.label().to_owned())
                }) {
                    Some(title) => self.article_row(project, ix, title, cx).into_any_element(),
                    None => Empty.into_any_element(),
                }
            }
            Row::Table { project, ix } => {
                match workspace
                    .projects
                    .get(project)
                    .and_then(|open| open.tables.get(ix).map(|table| table.name.clone()))
                {
                    Some(name) => self.table_row(project, ix, name, cx).into_any_element(),
                    None => Empty.into_any_element(),
                }
            }
        };
        div()
            .id(SharedString::from(format!("sidebar-hover-{}", key_of(row))))
            .when(!matches!(row, Row::Project(_) | Row::Archive(_)), |el| {
                el.on_hover(cx.listener(move |this, hovered: &bool, _, cx| {
                    this.sidebar_hover(Menu::Entry(row), *hovered, cx);
                }))
            })
            .h(px(ROW_HEIGHT))
            .py(px(1.))
            .child(inner)
            .into_any_element()
    }

    /// What the sidebar needs of a session, read when its row comes on screen.
    fn session_of(&self, project: usize, id: u64, cx: &Context<Self>) -> Option<SessionRow> {
        let workspace = self.workspace.read(cx);
        let chat = workspace.projects.get(project)?.session(id)?;
        Some(SessionRow {
            project,
            id: chat.id,
            label: chat.label(),
            icon: workspace.agent_icon(&chat.entry.name),
            working: chat.streaming.then(|| Working {
                state: transcript::orb_of(chat),
                since: chat.elapsed().unwrap_or_default(),
                frame: chat.transcript.mark.clone(),
            }),
            archived: chat.closed,
        })
    }

    /// The line the archive folds under: what is put away is still listed, a
    /// step below everything still in hand.
    fn archive_divider(&self, project: usize, cx: &mut Context<Self>) -> AnyElement {
        let theme = Theme::of(cx).clone();
        let open = self
            .workspace
            .read(cx)
            .projects
            .get(project)
            .is_some_and(|open| open.archive_open);
        row(
            ("archive", project),
            "archive-row",
            false,
            self.workspace.read(cx).indent_project_rows,
            &theme,
        )
        .child(theme.disclosure(open).text_color(theme.text_faint))
        .child(
            div()
                .flex_none()
                .text_style(TextStyle::Callout)
                .text_color(theme.text_faint)
                .child("Archived"),
        )
        .child(div().flex_1().h(px(1.)).bg(theme.border))
        .on_click(cx.listener(move |this, _, _, cx| this.toggle_archive(project, cx)))
        .into_any_element()
    }

    fn toggle_archive(&mut self, project: usize, cx: &mut Context<Self>) {
        self.commit(cx);
        self.workspace.update(cx, |workspace, cx| {
            if let Some(open) = workspace.projects.get_mut(project) {
                open.archive_open = !open.archive_open;
            }
            cx.notify();
        });
    }

    /// Menus address a project by its place in the list, so the one open when
    /// it moves would be pointing at whichever project slid underneath.
    fn move_project(&mut self, from: usize, to: usize, cx: &mut Context<Self>) {
        self.menu = None;
        self.workspace
            .update(cx, |workspace, cx| workspace.move_project(from, to, cx));
    }

    fn toggle_project(&mut self, ix: usize, cx: &mut Context<Self>) {
        self.commit(cx);
        self.workspace
            .update(cx, |workspace, cx| workspace.toggle_project(ix, cx));
    }

    /// What the `+` starts here. Session first: it is what the sidebar is for.
    ///
    /// With more than one agent installed the session row asks which, since
    /// the one `⌘N` would pick is whoever the project last talked to — which
    /// leaves every other agent with no way in.
    fn add_menu(&self, ix: usize, cx: &mut Context<Self>) -> Option<AnyElement> {
        if self.menu != Some(Menu::Add(ix)) {
            return None;
        }
        let workspace = self.workspace.read(cx);
        let features = &workspace.settings.features;
        let (sessions, boards, tables) = (features.sessions, features.boards, features.tables);
        let agents: Vec<(String, Option<Icon>)> = workspace
            .settings
            .agents
            .iter()
            .map(|entry| (entry.name.clone(), workspace.agent_icon(&entry.name)))
            .collect();
        let mut rows = Vec::new();
        if sessions && agents.len() > 1 {
            let picks = agents
                .into_iter()
                .enumerate()
                .map(|(at, (name, icon))| {
                    let icon = icon.unwrap_or_else(|| icons::social::MessageCircle.into());
                    menu::row(Item::action(name).with_icon(icon), move |this, _, cx| {
                        this.select_project(ix, cx);
                        this.pick_agent(at, cx);
                    })
                })
                .collect();
            rows.push(menu::submenu(
                "New session",
                icons::social::MessageCirclePlus,
                picks,
            ));
        } else if sessions {
            rows.push(menu::row(
                Item::action("New session").with_icon(icons::social::MessageCirclePlus),
                move |this, window, cx| {
                    this.select_project(ix, cx);
                    this.new_session_action(&NewSession, window, cx);
                },
            ));
        }
        if boards {
            rows.push(menu::row(
                Item::action("New board").with_icon(icons::development::SquareKanban),
                move |this, window, cx| this.ask_new_board(ix, window, cx),
            ));
        }
        rows.push(menu::row(
            Item::action("New article").with_icon(icons::files::FilePlus),
            move |this, window, cx| this.new_article(ix, window, cx),
        ));
        if tables {
            rows.push(menu::row(
                Item::action("New table").with_icon(icons::files::Table2),
                move |this, _, cx| this.new_table(ix, cx),
            ));
        }
        let id = SharedString::from(format!("add-menu-{ix}"));
        Some(popover::anchored_menu_below(
            id.clone(),
            self.menu_card(id, rows, cx),
            None,
        ))
    }

    /// What a press on the heading opens. Removing closes the tab — the
    /// directory and everything in it stays where it is.
    fn project_menu(&self, ix: usize, cx: &mut Context<Self>) -> Option<AnyElement> {
        if self.menu != Some(Menu::Project(ix)) {
            return None;
        }
        let rows = vec![menu::row(
            Item::action("Remove project").with_icon(icons::files::FolderMinus),
            move |this, _, cx| this.close_project(ix, cx),
        )];
        let id = SharedString::from(format!("project-menu-{ix}"));
        Some(popover::anchored_menu_below(
            id.clone(),
            self.menu_card(id, rows, cx),
            None,
        ))
    }

    /// One session: its mark and its name.
    fn session_row(&self, session: SessionRow, cx: &mut Context<Self>) -> AnyElement {
        let entry = Row::Session {
            project: session.project,
            id: session.id,
        };
        let theme = Theme::of(cx).clone();
        let id = session.id;
        let selected =
            self.showing(cx) == Some(Pane::Chat) && self.workspace.read(cx).active_id() == Some(id);
        let tint = tint(selected, session.archived, &theme);
        // The agent's own mark, in the label's colour rather than any of its
        // own: every icon the registry publishes is a `currentColor` glyph, so
        // tinting is the only colour it will ever have. While a turn is in
        // flight the orb stands in its place — the same one the transcript
        // works under.
        let mark = if let Some(working) = session.working {
            // Wider than the slot it sits in, and left to spill: the orb is a
            // sphere where the marks around it are glyphs, and widening the
            // column for it would move every label in the sidebar to make room
            // for a row that is only sometimes working.
            transcript::orb(working.state, working.since, &working.frame, cx)
        } else {
            match session.icon {
                Some(icon) => icons::icon(icon)
                    .size(px(14.))
                    .text_color(tint)
                    .into_any_element(),
                None => Empty.into_any_element(),
            }
        };

        // The band draws the field when it is showing this entry — see
        // [`Cydonia::header_renaming`], which is what keeps one field from
        // being claimed by two places at once.
        let label = match self.renaming == Some(Renaming::Session(id))
            && self.header_renaming(cx).is_none()
        {
            true => self.name_field(cx),
            false => row_label(session.label, tint),
        };

        row(
            ("session", id),
            "session-row",
            selected,
            self.workspace.read(cx).indent_project_rows,
            &theme,
        )
        .child(
            div()
                .flex_none()
                .size(px(14.))
                .flex()
                .items_center()
                .justify_center()
                .child(mark),
        )
        .child(label)
        .child(self.archive_button(("session-archive", id), entry, session.archived, cx))
        .on_click(cx.listener(move |this, _, _, cx| {
            this.select_session(id, cx);
        }))
        .into_any_element()
    }

    /// One board: its mark and its name.
    fn board_row(
        &self,
        project: usize,
        ix: usize,
        name: String,
        cx: &mut Context<Self>,
    ) -> AnyElement {
        let theme = Theme::of(cx).clone();
        let workspace = self.workspace.read(cx);
        let selected = self.showing(cx) == Some(Pane::Board)
            && workspace.active == Some(project)
            && workspace
                .projects
                .get(project)
                .is_some_and(|open| open.board == Some(ix));
        let entry = Row::Board { project, ix };
        let board = workspace
            .projects
            .get(project)
            .and_then(|open| open.boards.get(ix));
        let archived = board.is_some_and(|board| board.archived);
        let tint = tint(selected, archived, &theme);
        // No inline field on a board's row, ever: a board is named by its panel
        // — see [`Self::rename_entry`].
        let label = row_label(name, tint);

        row(
            SharedString::from(format!("board-{project}-{ix}")),
            "board-row",
            selected,
            workspace.indent_project_rows,
            &theme,
        )
        .child(
            icons::icon(icons::development::SquareKanban)
                .size(px(14.))
                .flex_none()
                .text_color(tint),
        )
        .child(label)
        .child(self.archive_button(
            SharedString::from(format!("board-archive-{project}-{ix}")),
            entry,
            archived,
            cx,
        ))
        .on_click(cx.listener(move |this, _, _, cx| this.open_board(project, ix, cx)))
        .into_any_element()
    }

    /// The button every sidebar row carries in place of a menu: one press puts
    /// the entry away, or takes it back out. Rename and delete are the header's
    /// — see [`Self::entry_menu`].
    ///
    /// Shown only while the pointer is on the row, resolved from
    /// `sidebar_hovered` during render: GPUI can resolve a hover style
    /// differently in prepaint and paint.
    pub(crate) fn archive_button(
        &self,
        id: impl Into<gpui::ElementId>,
        entry: Row,
        archived: bool,
        cx: &Context<Self>,
    ) -> Stateful<Div> {
        let theme = Theme::of(cx).clone();
        let mark = match archived {
            true => icons::files::ArchiveRestore,
            false => icons::files::Archive,
        };
        theme
            .ghost(id)
            .flex_none()
            .when(
                self.sidebar_hovered.as_ref() != Some(&Menu::Entry(entry)),
                |el| el.hidden(),
            )
            .p(px(3.))
            .child(icons::icon(mark).size(px(14.)).text_color(theme.text_faint))
            .tooltip(move |window, cx| {
                Tooltip::text(
                    match archived {
                        true => "Unarchive",
                        false => "Archive",
                    },
                    window,
                    cx,
                )
            })
            .on_click(cx.listener(move |this, _, _, cx| {
                cx.stop_propagation();
                this.archive_entry(entry, !archived, cx);
            }))
    }

    /// The `···` in the band: everything for the entry filling the window.
    ///
    /// Delete is offered here and not from a sidebar row. In the sidebar you
    /// are running a pointer down a list and the row under it is whichever one
    /// you stopped on; in the header there is one thing it could mean, and it
    /// is the thing filling the window. A row carries archive alone — see
    /// [`Self::archive_button`].
    pub(crate) fn entry_menu(
        &self,
        at: Menu,
        entry: Row,
        archived: bool,
        cx: &mut Context<Self>,
    ) -> Option<AnyElement> {
        if self.menu.as_ref() != Some(&at) {
            return None;
        }
        let put = match archived {
            true => Item::action("Unarchive").with_icon(icons::files::ArchiveRestore),
            false => Item::action("Archive").with_icon(icons::files::Archive),
        };
        // `../desktop`'s rule for what a `···` may carry: only commands with no
        // affordance on the object. An article's title is the head of its own
        // page and a board's name in the band opens its identity panel, so
        // neither is offered a second route here. Everywhere else the name is
        // display-only and this is the way.
        let named = !matches!(entry, Row::Article { .. } | Row::Board { .. });
        let mut rows = vec![menu::row(put, move |this, _, cx| {
            this.archive_entry(entry, !archived, cx)
        })];
        if named {
            rows.insert(
                0,
                menu::row(
                    Item::action("Rename").with_icon(icons::text::SquarePen),
                    move |this, window, cx| this.rename_entry(entry, window, cx),
                ),
            );
        }
        // A page's measure. An article is never `named`, so nothing it could
        // sit above is here.
        if matches!(entry, Row::Article { .. }) {
            let workspace = self.workspace.read(cx);
            let plain_chord = keymap::label(Command::PlainText, &workspace.settings.shortcuts)
                .unwrap_or_default();
            let held = workspace
                .active_article()
                .and_then(|article| article.full_width);
            let wide = held.unwrap_or(workspace.wide_pages);
            // Only for a page carrying a measure of its own. On every other
            // page it is already what is happening, and a row that undoes
            // nothing is a row nobody can read the point of.
            if held.is_some() {
                rows.insert(
                    0,
                    menu::row(
                        Item::action("Use default width").with_icon(icons::layout::Columns2),
                        move |this, _, cx| this.set_full_width(None, cx),
                    ),
                );
            }
            rows.insert(
                0,
                menu::row(
                    Item::action("Full width")
                        .with_icon(icons::layout::UnfoldHorizontal)
                        .checked(wide),
                    move |this, _, cx| this.set_full_width(Some(!wide), cx),
                ),
            );
            // The markdown itself, for the times the document is in the way of
            // it. Above the width, which is about the page rather than what is
            // being edited on it.
            rows.insert(
                0,
                menu::row(
                    Item::action("Plain text")
                        .with_icon(icons::text::Code)
                        .with_keystroke(plain_chord)
                        .checked(self.plain_text(cx).unwrap_or_default()),
                    move |this, window, cx| this.toggle_plain_text(&TogglePlainText, window, cx),
                ),
            );
        }
        rows.push(menu::row(
            Item::action("Delete").with_icon(icons::files::Trash),
            move |this, _, cx| this.ask_delete(entry, cx),
        ));
        let id = SharedString::from("header-menu-card");
        Some(popover::anchored_menu_below(
            id.clone(),
            self.menu_card(id, rows, cx),
            None,
        ))
    }

    /// Drop an entry, file and all. Deleting the session on screen lands on
    /// the first remaining entry in the sidebar's displayed order.
    pub(crate) fn delete_entry(&mut self, entry: Row, window: &mut Window, cx: &mut Context<Self>) {
        let landing_project = match entry {
            Row::Session { project, id }
                if self.showing(cx) == Some(Pane::Chat)
                    && self.workspace.read(cx).active == Some(project)
                    && self.workspace.read(cx).active_id() == Some(id) =>
            {
                Some(project)
            }
            _ => None,
        };
        self.commit(cx);
        self.workspace.update(cx, |workspace, cx| match entry {
            Row::Session { id, .. } => workspace.close_session(id, cx),
            Row::Board { project, ix } => workspace.delete_board(project, ix, cx),
            Row::Article { project, ix } => workspace.delete_article(project, ix, cx),
            Row::Table { project, ix } => workspace.delete_table(project, ix, cx),
            Row::Project(_) | Row::Archive(_) => {}
        });
        if let Some(project) = landing_project
            && let Some(landing) = self
                .entries(project, cx)
                .into_iter()
                .find(|row| !matches!(row, Row::Archive(_)))
        {
            self.open_row(landing, window, cx);
            self.reveal(landing, cx);
        }
        cx.notify();
    }

    /// Put the name field on an entry's row, for the kinds named that way.
    /// Each is addressed by what identifies it, so the field cannot slide onto
    /// its neighbour if the list reorders under it.
    ///
    /// A board is named by two things at once, so it opens its identity panel
    /// instead — which lives under the band, so the board is brought to the
    /// front first. One way to name a board, wherever you asked from.
    fn rename_entry(&mut self, entry: Row, window: &mut Window, cx: &mut Context<Self>) {
        if let Row::Board { project, ix } = entry {
            let id = self
                .workspace
                .read(cx)
                .projects
                .get(project)
                .and_then(|open| open.boards.get(ix))
                .map(|board| board.id.clone());
            if let Some(id) = id {
                self.open_board(project, ix, cx);
                self.open_info(&id, window, cx);
            }
            return;
        }
        let workspace = self.workspace.read(cx);
        let what = match entry {
            Row::Session { id, .. } => Some(Renaming::Session(id)),
            Row::Table { project, ix } => workspace
                .projects
                .get(project)
                .and_then(|open| open.tables.get(ix))
                .map(|table| Renaming::Table(table.key.clone())),
            // An article is named in its own page, and the two that are not
            // entries have no name to take.
            Row::Article { .. } | Row::Board { .. } | Row::Project(_) | Row::Archive(_) => None,
        };
        if let Some(what) = what {
            self.start_rename(what, window, cx);
        }
    }

    /// Put an entry away, or bring it back. Where the flag lives is each
    /// kind's own business — a board's file, an article's properties, a row in
    /// the store — and the sidebar asks for it the same way.
    fn archive_entry(&mut self, entry: Row, archived: bool, cx: &mut Context<Self>) {
        self.workspace.update(cx, |workspace, cx| match entry {
            Row::Session { id, .. } => workspace.archive_session(id, archived, cx),
            Row::Board { project, ix } => {
                if let Some(id) = workspace
                    .projects
                    .get(project)
                    .and_then(|open| open.boards.get(ix))
                    .map(|board| board.id.clone())
                {
                    workspace.archive_board(&id, archived, cx);
                }
            }
            Row::Article { project, ix } => {
                if let Some(path) = workspace
                    .projects
                    .get(project)
                    .and_then(|open| open.articles.get(ix))
                    .map(|article| article.path.clone())
                {
                    workspace.archive_article(&path, archived, cx);
                }
            }
            Row::Table { project, ix } => {
                if let Some(key) = workspace
                    .projects
                    .get(project)
                    .and_then(|open| open.tables.get(ix))
                    .map(|table| table.key.clone())
                {
                    workspace.archive_table(&key, archived, cx);
                }
            }
            Row::Project(_) | Row::Archive(_) => {}
        });
    }

    /// The field, in the row's place. It carries its own press: `TextField`
    /// does not focus itself, and a press that reached the row would open what
    /// is being named out from under the name.
    pub(crate) fn name_field(&self, cx: &mut Context<Self>) -> AnyElement {
        div()
            .flex_1()
            .min_w_0()
            .on_mouse_down(
                MouseButton::Left,
                cx.listener(|this, _, window, cx| {
                    cx.stop_propagation();
                    window.focus(&this.name_field.read(cx).focus_handle(cx), cx);
                }),
            )
            // Pressing anywhere else is finishing, not abandoning — the name
            // typed is the name meant. `escape` is what discards.
            .on_mouse_down_out(cx.listener(|this, _, window, cx| {
                this.commit_name(&CommitName, window, cx);
            }))
            .child(self.name_field.clone())
            .into_any_element()
    }

    pub(crate) fn start_rename(
        &mut self,
        what: Renaming,
        window: &mut Window,
        cx: &mut Context<Self>,
    ) {
        let workspace = self.workspace.read(cx);
        let label = match &what {
            Renaming::Session(id) => workspace
                .session(*id)
                .map(ChatSession::label)
                .unwrap_or_default(),
            Renaming::Table(key) => workspace
                .projects
                .iter()
                .flat_map(|open| open.tables.iter())
                .find(|table| table.key == *key)
                .map(|table| table.name.clone())
                .unwrap_or_default(),
            Renaming::Column(id) => workspace
                .active_board()
                .and_then(|board| board.column(id))
                .map(|column| column.name.clone())
                .unwrap_or_default(),
        };
        // A lane is named in one case — see [`artifact::board::column::heading`]
        // — and the field is put in it before the name lands, so what is typed
        // and what is stored are the same string.
        let case = match &what {
            Renaming::Column(_) => Case::Upper,
            _ => Case::Mixed,
        };
        self.name_field.update(cx, |field, cx| {
            field.set_case(case);
            field.set_content(label, cx);
        });
        // See [`Cydonia::open_info`] — the other way round.
        self.info = None;
        self.renaming = Some(what);
        window.focus(&self.name_field.read(cx).focus_handle(cx), cx);
        cx.notify();
    }

    pub(crate) fn commit_name(&mut self, _: &CommitName, _: &mut Window, cx: &mut Context<Self>) {
        let Some(what) = self.renaming.take() else {
            return;
        };
        let name = self.name_field.read(cx).content().to_string();
        self.workspace.update(cx, |workspace, cx| match what {
            Renaming::Session(id) => workspace.rename_session(id, name, cx),
            Renaming::Table(key) => workspace.rename_table(&key, name, cx),
            Renaming::Column(id) => workspace.rename_column(&id, name, cx),
        });
        cx.notify();
    }

    pub(crate) fn dismiss_name(&mut self, _: &DismissName, _: &mut Window, cx: &mut Context<Self>) {
        self.renaming = None;
        cx.notify();
    }
}