sprawling-runtime 0.0.10

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.
// Copyright (c) 2026 2youg1 and the sprawling contributors

//! What a completed turn hands the run loop, and the frozen `[model]`
//! section the call is shaped by.

use kernel::{AxCode, AxError, Ceiling, ContentBlock, ModelUsage, StopReason};

use super::Entry;

/// What a completed turn hands the run loop. `assistant` and
/// `wave_results` are the window-folding material — the turn's
/// exchange, compacted at the closing boundary of `record`. The records
/// are what the compaction works from: `model_returned.data.content`
/// keeps the reply whole, and each `tool_result` is the payload the
/// window text was printed from. `runtime::fork` rebuilds both from
/// those records through the same compaction at the same boundary, so a
/// rebuild and a live fold still share one source.
#[derive(Debug, Clone, PartialEq)]
pub struct TurnReport {
    pub(super) redacted: u32,
    pub(super) model_returned: Entry,
    pub(super) calls_made: usize,
    pub(super) assistant: Vec<ContentBlock>,
    pub(super) wave_results: Vec<ContentBlock>,
    pub(super) usage: Option<ModelUsage>,
    pub(super) stop: Option<StopReason>,
}

impl TurnReport {
    /// What the provider counted for this call, when it said. The
    /// context gauge reads `input_tokens` from here and nowhere else.
    pub fn usage(&self) -> Option<&ModelUsage> {
        self.usage.as_ref()
    }

    /// How many secret-shaped spans this turn replaced before its model
    /// and tool events reached the ledger. A diagnostic line can say
    /// this number without saying what was found.
    pub fn redacted(&self) -> u32 {
        self.redacted
    }

    /// The in-window evidence candidate for `Completion::Done`, by its
    /// place among the run's lines: `HeldLines::durable` gives its ref
    /// once a barrier has carried it (runtime D36).
    pub fn model_returned(&self) -> Entry {
        self.model_returned
    }

    pub fn calls_made(&self) -> usize {
        self.calls_made
    }

    pub fn assistant(&self) -> &[ContentBlock] {
        &self.assistant
    }

    pub fn wave_results(&self) -> &[ContentBlock] {
        &self.wave_results
    }

    /// Why the provider stopped, when it said. A reply that stopped at
    /// the ceiling is a reply that was cut off, and the run loop reads
    /// that here rather than inferring it from what the reply contains.
    pub fn stop(&self) -> Option<StopReason> {
        self.stop
    }
}

/// Which model this run calls, how much it may say, and how hard it may
/// think — the frozen `[model]` config section as the turn sees it.
/// `effort` comes from [`kernel::FrozenConfig`] and cannot change within
/// the run: the provider renders it into the cached prompt prefix.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct CallShape {
    pub model: String,
    /// The model's own ceiling, from the endpoint book. `None` when no
    /// catalogue row states one: the request then carries no ceiling and
    /// the wire that requires one refuses the call.
    pub max_tokens: Option<Ceiling>,
    pub effort: Option<kernel::Effort>,
    /// The model's window, from the endpoint book. Zero when the book
    /// does not say, in which case the context reminder stays silent.
    pub context_tokens: u64,
}

impl CallShape {
    /// Refuses a shape that differs from the one a session froze.
    ///
    /// The model, its output ceiling and its effort are the fields that
    /// reach the provider's wire; changing any of them mid-session
    /// invalidates the message cache breakpoints the frozen prefix is
    /// paid for, which is why they freeze with the session rather than
    /// with a form. `context_tokens` is not one of them: it sizes this
    /// machine's own reminder and never leaves it.
    ///
    /// This is the runtime's half of the interception the dispatch face
    /// owes: `Command::Dispatch { effort }` writes a room's effort, and
    /// whoever lets that write through asks here first.
    ///
    /// # Errors
    /// `ConfigInvalid`, naming the field that moved and the two ways
    /// out.
    pub fn verified_against(&self, frozen: &CallShape) -> Result<(), AxError> {
        if self.model != frozen.model {
            return Err(shape_moved(format!(
                "the model changed from `{}` to `{}`",
                frozen.model, self.model
            )));
        }
        if self.effort != frozen.effort {
            return Err(shape_moved(format!(
                "the effort changed from {:?} to {:?}",
                frozen.effort, self.effort
            )));
        }
        if self.max_tokens != frozen.max_tokens {
            return Err(shape_moved("the output ceiling changed".to_owned()));
        }
        Ok(())
    }
}

/// The refusal a call shape that moved under a running session earns.
///
/// The recovery names what a person can do from the page in front of
/// them: put the field the subject names back, or leave this session
/// by addressing another room. The second way out is spelled in one
/// place (`prefix::segment::ANOTHER_ADDRESS`), so no refusal here can
/// name a verb the wire does not carry.
fn shape_moved(subject: String) -> AxError {
    AxError::failure(AxCode::ConfigInvalid, "dispatch a turn", subject).with_recovery(format!(
        "put the field the subject names back to what this session froze, or \
         {}: the model, its ceiling and its effort freeze with the session, \
         and a mid-run change would invalidate the prefix the run is paying to cache",
        crate::prefix::ANOTHER_ADDRESS
    ))
}