lernie 0.1.65

//! **What the window holds between frames** — the struct, and nothing else.
//!
//! Split from [`super`] at the 300-line cap on the seam that module's own doc
//! draws: [`super`] is the module list and the re-export surface, and this is
//! the snapshot a frame reads. Nothing here paints and nothing here dials, so
//! every rule for changing it is a pure function a test reads back as a value.
//!
//! **The questions asked of it are [`asked`]**, split off at the same cap when
//! the drag added the second of them: a field is what a pane learned to hold,
//! and a question is what two panes turned out to need one answer to.

/// The two questions asked of the model that no pane owns.
mod asked;

use super::{
    Aim, Asking, Authoring, Bindings, Chunk, Columns, Configuring, Diagnosis, Dragged, Engines,
    Enrolling, Fill, Fleet, Forking, Hits, Listing, Login, Lookup, Notice, Pages, Posted, Records,
    Start, Trail, Tuning, Unmaking,
};
use crate::reply::convs::ConvRow;
use crate::reply::stream::Stream;
use crate::reply::transcript::Transcript;

/// Everything the window holds between frames.
#[derive(Debug, Clone, Default)]
pub struct Model {
    /// Every channel's workspaces, in the order the channels were asked.
    pub roster: Vec<Chunk>,
    /// The aimed wall's conversations.
    pub convs: Vec<ConvRow>,
    /// **Which wall [`Self::convs`] is the ANSWER to**, or `None` while the aim
    /// has not been answered about at all (bl-f780).
    ///
    /// It rides beside the rows rather than being derived, because emptiness
    /// cannot tell the two apart: a wall that answered zero conversations and a
    /// wall nobody has asked about yet hold the same `Vec`, and painting *"no
    /// conversations here"* over the second states a definite fact about a wall
    /// nobody looked at — the same thing `crate::ui::convs::UNCERTAIN` refuses
    /// to do one level down, on a conversation nobody could take a reading of.
    ///
    /// It is set and cleared at exactly the two places `convs` is, and nowhere
    /// else.
    pub answered: Option<Aim>,
    /// **What the aimed wall's roles are set to**, or `None` while nobody has
    /// been answered about them — one field where [`Self::convs`] needs a pair,
    /// because here the option carries the whole distinction (`tuning`).
    pub roles: Option<Vec<crate::reply::roles::RoleRow>>,
    /// **The tuning pane, while it is open** — the second pane in this window
    /// that covers the conversation ([`Tuning`]).
    pub tuning: Option<Tuning>,
    /// **Which of the three LISTING panes is standing**, if any — the records
    /// pane, the decision queue, or the clients pane (`listing`). One field
    /// rather than a flag each: they hold nothing of their own, no two ever
    /// stand together, and three bools would make *two of them open at once* a
    /// state only the derivation order resolves — the reframe clippy's
    /// `struct_excessive_bools` names, taken rather than suppressed.
    pub listing: Option<Listing>,
    /// **The machines registered in the aimed wall's workspace**, or `None`
    /// while nobody has been answered about it — the one-option reading
    /// [`Self::roles`] gets, one noun over (`clients`).
    pub machines: Option<Vec<crate::reply::clients::ClientRow>>,
    /// **The config pane, while it is open** — the eleventh covering pane, and
    /// the fourth whose subject is the aimed wall (`config`; DESIGN §4.30). A
    /// struct rather than a flag because it holds one question of its own:
    /// which file it is pointed at.
    pub configuring: Option<Configuring>,
    /// **One config file's bytes and the settings its schema found**, or
    /// `None` while nobody has been answered about the file the pane points at
    /// — the one-option reading [`Self::roles`] gets (`config`).
    pub config: Option<crate::reply::config::Config>,
    /// **The aimed wall's config lineages**, on the same standing (`config`).
    pub lineages: Option<Vec<crate::reply::lineages::Lineage>>,
    /// **What a reviewer has staged for it**, on the same standing (bl-a1d6).
    pub proposals: Option<crate::reply::proposals::Proposals>,
    /// **The login pane, while it is open** — the eighth covering pane, and
    /// the second whose subject is the aimed wall (`login`; DESIGN §4.24). A
    /// struct rather than a flag because it holds two questions of its own:
    /// which row a sign-in is being followed on, and which was asked what it
    /// offers.
    pub login: Option<Login>,
    /// **What the aimed wall can sign in to**, or `None` while nobody has been
    /// answered about it — the one-option reading [`Self::roles`] gets, and
    /// filed here rather than on the pane because the rows are the engine's.
    pub providers: Option<Vec<crate::reply::providers::ProviderRow>>,
    /// **What the last row asked answered with** — the posted read's answer,
    /// dropped by the act that asks another (`login`). Which row it is about
    /// is the pane's `asking`, because the reply carries no name.
    pub offered: Option<Vec<String>>,
    /// **The sign-in run this seat is following**, as the lane has folded it —
    /// the login pane's held read, and [`Self::live`]'s shape one noun over
    /// (`login`).
    pub signin: Option<crate::reply::login::Signin>,
    /// **Which of the window's own three panes is standing**, if any — the
    /// sixth, seventh and tenth covering panes, and the three whose subject is
    /// every channel and which are opened from the roster's own ops row
    /// (`window`, `trail`; bl-40ec, bl-4c48). One field rather than three
    /// flags, because no two panes ever stand together and a set of bools
    /// would make *all three* representable — which is also the reframe
    /// clippy's `struct_excessive_bools` asks for by name, taken rather than
    /// suppressed.
    ///
    /// It is a second field beside [`Self::listing`] and not one with it,
    /// because the two name different axes: these three are the WINDOW's own —
    /// reached from the ops row, about every channel, and one of them holds a
    /// needle — while a listing is a pane about one thing on the glass that
    /// holds nothing at all. DESIGN §4.28 records the fold that would make
    /// them one.
    pub lookup: Option<Lookup>,
    /// **An unmaking, while it stands** — the fifth covering pane, and the only
    /// one this window has whose act cannot be undone by doing the other thing
    /// (`unmake`; DESIGN §4.20). It carries the wall it was opened on rather
    /// than following the aim, because the roster stays live under it.
    pub unmaking: Option<Unmaking>,
    /// **What each channel last said is asking for the operator**, one section
    /// per channel and the union across them. A `Vec` rather than an option
    /// because the emptiness that matters is per channel: nothing here at all
    /// is nobody answered yet, and a section holding no row is an engine that
    /// answered and holds nothing waiting (`queue`).
    pub waiting: Vec<Asking>,
    /// **What each channel last said has crossed its boundary** — the same
    /// per-channel reading, one noun over (`trail`; bl-4c48).
    pub trails: Vec<Trail>,
    /// **What each channel last said its board is** — every live ball in its
    /// column and the loops running them, on the trail's own per-channel
    /// reading (`board`; bl-d2af).
    pub columns: Vec<Columns>,
    /// **What each channel last said its ball⇄workspace bindings are**, on the
    /// same terms (`board`).
    pub bindings: Vec<Bindings>,
    /// **What the aimed wall last said it holds**, or `None` while nobody has
    /// been answered about it — the one-option reading [`Self::roles`] gets,
    /// and retired with the aim for the same reason (`board`).
    pub holding: Option<Vec<crate::reply::balls::BoundBall>>,
    /// **The branch the aimed wall tracks its tasks on**, on the same standing
    /// (`board`).
    pub marks: Option<String>,
    /// **A ball's text being authored, while the block is open** (`board::
    /// acts`; DESIGN §4.35, bl-f7ae). A struct rather than a flag because it
    /// holds the wall it was opened on and the name that wall's engine knows
    /// it by, and because one block serves two subjects — a ball that does not
    /// exist yet, and one this wall holds.
    pub authoring: Option<Authoring>,
    /// **The fleet pane, while it is open** — the thirteenth covering pane,
    /// and the fifth whose subject is the aimed wall (`fleet`; DESIGN §4.33).
    /// A struct rather than a flag because three of its five acts carry a word
    /// nothing on the glass can derive, and because it holds the wall it was
    /// opened on rather than following the aim.
    pub fleet: Option<Fleet>,
    /// **The aimed wall's delivery attempts**, or `None` while nobody has been
    /// answered — the one-option reading [`Self::roles`] gets (`fleet`).
    pub attempts: Option<Vec<crate::reply::science::Attempt>>,
    /// **What its agents changed**, on the same standing (`fleet`).
    pub work: Option<Vec<crate::reply::diff::Diff>>,
    /// **What each channel last said it answers to** — the same per-channel
    /// reading, one noun over (`window`; bl-40ec).
    pub pages: Vec<Pages>,
    /// **What each channel last found**, on the same terms (`window`).
    pub found: Vec<Hits>,
    /// **What each channel said about its own wiring** (`doctor`; bl-9bbb).
    pub diagnoses: Vec<Diagnosis>,
    /// **What to look for.** A box the find pane holds and does not spend on
    /// firing, because refining a needle is the common act — unlike the
    /// composer's draft, which was sent (`window`).
    pub needle: String,
    /// **The draft a fork is composed from** (`spine`): the role and the goal,
    /// beside the `from` each control carries off its own notch. A bare field
    /// and not an option, exactly as the composer's two parameter boxes are —
    /// the boxes are on the glass whenever the spine is.
    pub forking: Forking,
    /// **The arming for the cascade** (`crate::ui::records::cascade`): the
    /// conversation's own name typed back, which is what admits the
    /// conversations under it into a stop. It is this seat's own enablement
    /// and not a wire field — `stop` carries a boolean flag and no `typed` —
    /// so it is never sent, only read (DESIGN §4.20's amended scope rule).
    pub cascade: String,
    /// **What the records pane has been answered** — its seven reads, held
    /// together because they are one pane's questions about one subject and
    /// they are retired together when that subject moves (`records`).
    ///
    /// A struct rather than seven fields, on `listing`'s own reasoning one
    /// layer over: seven options on this struct would be seven places to
    /// remember when a selection moves, and forgetting one paints a
    /// conversation's records under another's name.
    pub records: Records,
    /// The selected conversation, as committed.
    pub transcript: Transcript,
    /// The live tail as this seat has accumulated it. It **replaces**, never
    /// accretes — and since PROTOCOL 2 that is a statement about where the
    /// accretion happens rather than whether it does: a follow frame is an
    /// append (REMOTE §5.5), so `crate::offframe::follow` absorbs each frame
    /// onto the read's own fold and what reaches here is already whole. The
    /// fold's lifetime is one read, which is what keeps two reads of one
    /// conversation from running into each other.
    pub live: Option<Stream>,
    /// What the seat last heard that was not content.
    pub notice: Option<Notice>,
    /// Which wall the window is aimed at.
    pub aim: Option<Aim>,
    /// **The edges the operator has dragged** (`dragged`; DESIGN §4.39). One
    /// field rather than three, because the three are one fact — what this
    /// seat holds of its own layout — and they are written down together
    /// (`crate::place`).
    pub dragged: Dragged,
    /// **How the engines are arranged** (DESIGN §4.39, `engines`): which one
    /// is open, when each was last opened here, and the wall last aimed under
    /// each. One field rather than three, because the three are one subject
    /// and they are written down together ([`crate::place`]).
    pub engines: Engines,
    /// **Which engine row the roster's walk is standing on**, or `None` where
    /// the cursor is on a wall.
    ///
    /// It is the one place in this window where the cursor is NOT the
    /// selection, and DESIGN §4.39 says why: opening an engine is an act, so a
    /// walk that moved through a closed engine would open every engine it
    /// passed. So the walk stands on the row, the row takes the keyboard, and
    /// Enter or Space fires the same click a pointer fires. It rides here and
    /// not on `Engines`, because it is a cursor and nothing durable.
    pub standing: Option<String>,
    /// **Which column is on the glass in the narrow shape** — a navigation the
    /// operator performed, so it is the one thing here no other fact can be
    /// asked for. The broad shape never reads it, because every column is on
    /// the glass there (`crate::ui::shell::policy`).
    pub column: crate::ui::Column,
    /// **Whether the list owes its selection a place on the glass**, set by a
    /// keyboard walk and taken by the pane that paints it
    /// ([`Model::revealing`]).
    ///
    /// The keyboard is the only surface that can move a selection out of view:
    /// a click names a row the operator is already looking at, and a scroll IS
    /// the operator deciding what to look at — so a pane that revealed on every
    /// frame would drag the glass back every time they scrolled away.
    pub reveal: bool,
    /// The selected conversation's id.
    pub conversation: Option<String>,
    /// **Which conversations have had their subtree opened** (`subtree`;
    /// bl-00f5).
    ///
    /// A set of what is OPEN rather than of what is folded, so the default
    /// costs no state at all: a seat that has never been told otherwise shows
    /// the conversations and not the machinery under them. It is a navigation
    /// the operator performed, which is the one class of thing on this struct
    /// no other fact can be asked for — [`Self::column`]'s own standing.
    pub opened: std::collections::BTreeSet<String>,
    /// What the operator has typed and not yet sent.
    pub draft: String,
    /// **The arming for the unmaking** (`crate::ui::composer::acts`): the name
    /// typed back, which is what admits a conversation's descendants into its
    /// deletion. Empty is the bare form and deletes the one conversation, so
    /// this is not a second control's enablement — it is the gesture's own
    /// third parameter, held where the box that fills it is.
    pub typed: String,
    /// **Which of the two boxes above a row menu asked for the cursor in**, or
    /// `None` where nobody has asked (`fill`; bl-dbc9). A conversation row's
    /// menu cannot hold either box, so the item that would need one goes to it
    /// instead — and this is the request, taken by the frame that paints it.
    pub fill: Option<Fill>,
    /// **The words a flag is raised with** (`crate::ui::composer::acts`). The
    /// wire requires them — a flag with nothing in it is a row nobody can
    /// triage — so the control is disabled until there are any, and the box is
    /// SPENT on firing: what a flag says is said, exactly as a deposit is.
    pub reason: String,
    /// **Whether the next conversation is born on the planner role** (DESIGN
    /// §4.39; REMOTE §9.21, PROTOCOL 18) — the one parameter a start has, and
    /// the whole of what the composer's start-mode row carries
    /// (`crate::ui::composer::offers`).
    ///
    /// It is held here and not with the start itself because it is stated
    /// **between** the stage and the fire: the frame that absorbs `prepare`'s
    /// receipt is what writes the field onto the body it hands back
    /// (`start::Model::fire`), and that frame reads the window, not the
    /// gesture. A bool rather than the role's own name, because the name is
    /// `crate::verbs::start::PLANNER` and a second copy of it here would be a
    /// second place for the wire's word to live.
    pub plan: bool,
    /// **A start, while it is happening** — the one thing this window holds
    /// across a round trip, because starting is two acts and the second is
    /// composed from the first's answer ([`Start`]).
    pub start: Option<Start>,
    /// **An enrollment, while it is happening** — the second thing this window
    /// holds across a round trip, and the only thing it ever holds that is a
    /// secret. It is dropped by a control and written down nowhere
    /// ([`Enrolling`]).
    pub enroll: Option<Enrolling>,
    /// **The gestures this frame composed**, for whoever can send them. A frame
    /// that posted its own would be a frame that waits.
    ///
    /// Each carries whether it is an ACT, said by the control that composed it,
    /// because a lost reply means opposite things for the two ([`Posted`]).
    pub outbox: Vec<Posted>,
}