yog 0.0.2

//! The line's **per-verb** argument builders (§8.5) — one small function per
//! grammar that is more than a bare tail, split out of [`super::parse`] at
//! §12's per-file budget. The seam is real: [`super::parse`] holds the verb
//! table and the higher-order help rule, this holds what each verb makes of
//! its words, and [`super::args`] the total helpers they all share.

use super::{Context, args};
use crate::boundary::{Action, Gesture};
use crate::monitor::Verb;
use crate::start::{BallSpec, Payload};
use std::path::PathBuf;

/// `/seen` — the §6 queue's answer. The seat's own selection is the item,
/// exactly as it is for `/message`: answering and acknowledging aim alike, so
/// the line names neither and the context supplies both.
pub(super) fn seen(tail: &str, ctx: &Context, verb: &str) -> Result<Gesture, String> {
    args::none(tail, verb)?;
    Ok(act(Action::MarkSeen {
        workspace: args::workspace(ctx, verb)?,
        agent: args::agent(ctx, verb)?,
    }))
}

/// `/answer pass|hold|refuse` — the §4.11 capability answer. The conversation
/// is the seat's, like `/seen`'s; the held `tool_use` id is derived at fire
/// time, so the only word a line can carry is the verdict — and it is
/// required, because an answer with a default verdict would be yog deciding.
pub(super) fn answer(tail: &str, ctx: &Context, verb: &str) -> Result<Gesture, String> {
    let word = args::required(tail, verb, "pass, hold or refuse")?;
    let ruling = crate::control::judge::Ruling::of(word.trim())
        .ok_or_else(|| format!("/{verb}: unknown verdict {word:?}; usage: {ANSWER_USAGE}"))?;
    Ok(act(Action::AnswerHold {
        workspace: args::workspace(ctx, verb)?,
        agent: args::agent(ctx, verb)?,
        ruling,
    }))
}

/// `/answer`'s usage, said once — the refusal above and the help page below
/// read this one string.
pub const ANSWER_USAGE: &str = "/answer pass | hold | refuse";

/// `/revoke` and `/restore` — VISION §4.9's fifth rung over the §4.11 fold.
/// Neither names anything but itself: the conversation is the seat's own, as
/// `/answer`'s and `/flag`'s are, and the direction is the verb rather than a
/// word after it, because raising and lowering are two instructions and a
/// gesture is never read out of an absence.
pub(super) fn floor(verb: &str, tail: &str, ctx: &Context) -> Result<Gesture, String> {
    args::none(tail, verb)?;
    Ok(act(Action::Floor {
        workspace: args::workspace(ctx, verb)?,
        agent: args::agent(ctx, verb)?,
        raised: verb == "revoke",
    }))
}

/// `/ops` with no count: the tail an operator means by "what just happened".
const OPS_DEFAULT: usize = 50;

fn act(action: Action) -> Gesture {
    Gesture::Act(action)
}

/// `/stop [children]` — the cascade is a word, not a flag: it is the checkbox
/// beside the button, and a checkbox spells as the thing being checked.
pub(super) fn children(tail: &str) -> Result<bool, String> {
    match tail.trim() {
        "" => Ok(false),
        "children" => Ok(true),
        other => Err(format!(
            "/stop: unexpected {other:?}; usage: /stop [children]"
        )),
    }
}

/// The ball an id-taking verb acts on: the typed word, else the focused ball.
pub(super) fn id(tail: &str, ctx: &Context, verb: &str) -> Result<String, String> {
    args::ball_id(args::optional_word(tail, verb)?, ctx, verb)
}

/// `/move [id] <to>` — one word is the destination for the focused ball, two
/// are the ball and its destination. `from` is the seat's own §3.2 stamp.
pub(super) fn moved(tail: &str, ctx: &Context, verb: &str) -> Result<Gesture, String> {
    let (ball, to) = match tail.split_whitespace().collect::<Vec<_>>().as_slice() {
        [to] => (args::ball_id(None, ctx, verb)?, (*to).to_owned()),
        [id, to] => ((*id).to_owned(), (*to).to_owned()),
        _ => return Err(format!("/{verb}: usage: /move [id] <to>")),
    };
    Ok(act(Action::Move {
        project: args::project(ctx, verb)?,
        id: ball,
        from: args::name(ctx, verb)?,
        to,
    }))
}

/// `/create <title…> [--body <text…>]`.
pub(super) fn create(tail: &str, ctx: &Context, verb: &str) -> Result<Gesture, String> {
    let (title, flags) = args::split_flags(tail);
    args::only(&flags, &["body"], verb)?;
    Ok(act(Action::Create {
        project: args::project(ctx, verb)?,
        title: args::required(&title, verb, "a title")?,
        name: args::name(ctx, verb)?,
        body: args::flag(&flags, "body", verb)?,
    }))
}

/// `/update [id] [--title T] [--body B] [--note N]` — at least one field, or
/// the line asked for nothing and the refusal says so.
pub(super) fn update(tail: &str, ctx: &Context, verb: &str) -> Result<Gesture, String> {
    let (positional, flags) = args::split_flags(tail);
    args::only(&flags, &["title", "body", "note"], verb)?;
    let (title, body, note) = (
        args::flag(&flags, "title", verb)?,
        args::flag(&flags, "body", verb)?,
        args::flag(&flags, "note", verb)?,
    );
    if title.is_none() && body.is_none() && note.is_none() {
        return Err(format!(
            "/{verb}: nothing to change; usage: /update [id] [--title T] [--body B] [--note N]"
        ));
    }
    Ok(act(Action::Update {
        project: args::project(ctx, verb)?,
        id: id(&positional, ctx, verb)?,
        name: args::name(ctx, verb)?,
        title,
        body,
        note,
    }))
}

/// The §3.4 payload rung, said outright: nothing is the bare rung, `dir <path>`
/// the path rung, `ball` the focused ball (or `--new <title…>` for one this
/// line mints). The rung is never inferred from what happens to be selected —
/// a start that silently picked a different rung is the one mistake this whole
/// grammar exists to make impossible.
pub(super) fn payload(tail: &str, ctx: &Context, verb: &str) -> Result<Payload, String> {
    let (rung, rest) = args::first_word(tail);
    match rung.as_str() {
        "" => Ok(Payload::Bare),
        "dir" => Ok(Payload::Path {
            dir: PathBuf::from(args::required(&rest, verb, "a work directory")?),
        }),
        "ball" => Ok(Payload::Ball {
            project: args::project(ctx, verb)?,
            ball: spec(&rest, ctx, verb)?,
        }),
        other => Err(format!(
            "/{verb}: unknown rung {other:?}; usage: /prepare | /prepare dir <path> | /prepare ball [--new <title…>]"
        )),
    }
}

/// The ball a `/prepare ball` starts from: the focused one, or a new one this
/// line names. An **existing** ball carries roster facts (title, body, its §3.5
/// join) that no line can state, so it comes from the seat's selection or not
/// at all — a seat holding no roster spells this gesture as an envelope.
fn spec(rest: &str, ctx: &Context, verb: &str) -> Result<BallSpec, String> {
    let (positional, flags) = args::split_flags(rest);
    args::only(&flags, &["new", "body"], verb)?;
    args::none(&positional, verb)?;
    match args::flag(&flags, "new", verb)? {
        Some(title) => Ok(BallSpec::New {
            title,
            body: args::flag(&flags, "body", verb)?.unwrap_or_default(),
        }),
        None => ctx.ball.clone().ok_or_else(|| {
            format!("/{verb}: no ball is selected — select one, or say --new <title…>")
        }),
    }
}

/// `/work-diff [<ball> <path>]` — the file a patch read names, or nothing at
/// all for the listing.
pub(super) fn work_file(
    tail: &str,
    verb: &str,
) -> Result<Option<crate::workdiff::WorkFile>, String> {
    match tail.split_whitespace().collect::<Vec<_>>().as_slice() {
        [] => Ok(None),
        [ball, path] => Ok(Some(crate::workdiff::WorkFile {
            ball: (*ball).to_owned(),
            path: (*path).to_owned(),
        })),
        _ => Err(format!("/{verb}: usage: /work-diff [<ball> <path>]")),
    }
}

/// `/ops [n]` — how deep to read the trail.
pub(super) fn max(tail: &str) -> Result<usize, String> {
    match args::optional_word(tail, "ops")? {
        None => Ok(OPS_DEFAULT),
        Some(word) => word
            .parse()
            .map_err(|_| format!("/ops: {word:?} is not a row count")),
    }
}

/// The VISION §4.9 monitor's three, read as one family (they are one boundary
/// variant). `/arm <model>` — the model pin is arming's whole parameter, with
/// no default: it decides what every check costs, and guessing it would spend
/// the operator's money on yog's opinion. `/disarm` names nothing at all — its
/// own verb rather than an arm with no pin, because it is its own instruction.
/// `/flag <why…>` requires its reason: an attention item with nothing behind it
/// is a light the operator reading the trail tomorrow pays for.
pub(super) fn monitor(verb: &str, tail: &str, ctx: &Context) -> Result<Gesture, String> {
    let workspace = args::workspace(ctx, verb)?;
    let gesture = match verb {
        "arm" => Verb::Arm {
            workspace,
            model: args::required(tail, verb, "the model to check with")?,
        },
        "disarm" => {
            args::none(tail, verb)?;
            Verb::Disarm { workspace }
        }
        _ => Verb::Flag {
            workspace,
            agent: args::agent(ctx, verb)?,
            reason: args::required(tail, verb, "why")?,
        },
    };
    Ok(act(Action::Monitor(gesture)))
}

/// The VISION §4.3 loop's two, read as one family (they are one boundary
/// variant). `/fleet <cap>` — the cap is arming's whole typed parameter, with
/// no default: it decides how many drones this workspace may run at once, and
/// guessing it would spend the operator's money on yog's opinion. The project
/// it takes work from is the seat's own, like every other `bl`-family target.
/// `/disband` names nothing at all — its own verb rather than a `/fleet 0`,
/// because a zero cap is an armed loop that still reaps and is a different
/// instruction.
pub(super) fn fleet(verb: &str, tail: &str, ctx: &Context) -> Result<Gesture, String> {
    let workspace = args::workspace(ctx, verb)?;
    let gesture = if verb == crate::boundary::codec::FLEET_ARM {
        let word = args::required(tail, verb, "the cap — how many balls at once")?;
        crate::fleet::Verb::Arm {
            workspace,
            project: args::project(ctx, verb)?,
            cap: word
                .parse()
                .map_err(|_| format!("/{verb}: {word:?} is not a cap"))?,
        }
    } else {
        args::none(tail, verb)?;
        crate::fleet::Verb::Disarm { workspace }
    };
    Ok(act(Action::Fleet(gesture)))
}