supercode-harness 0.4.4

//! Acceptance tests for SPEC.md A7 (agent-loop-integrated reversible
//! tool-output truncation), A9 (image/base64 redaction through the agent
//! write-through), and A10 (old-turn clearing; re-founded `maybe_compact`).
//!
//! `reduce_projection.rs` covers `project()`/`project_messages()` as pure
//! functions in isolation; this file covers the two things that only show up
//! once an `Agent` is driving the loop: (1) the request view is built from
//! the *projected* history, not raw history, and (2) `maybe_compact` no
//! longer performs destructive surgery once a `ReductionPolicy` is active.

use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::{Arc, Mutex};

use async_trait::async_trait;
use supercode_harness::reduce::{
    invert, project, project_messages, reduction_id, ReductionKind, ReductionLog, ReductionPolicy,
    REDUCTION_SENTINEL,
};
use supercode_harness::session::Session;
use supercode_harness::sidecar::SidecarWriter;
use supercode_harness::{
    Agent, ChatMessage, ChatRequest, Config, FunctionCall, Provider, Role, ToolCall, Usage,
};

fn fixture(name: &str) -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR"))
        .join("tests/fixtures")
        .join(name)
}

fn load_codex() -> Session {
    Session::from_codex(fixture("codex_session.jsonl")).unwrap()
}

fn tool_indices(session: &Session) -> Vec<usize> {
    session
        .messages
        .iter()
        .enumerate()
        .filter(|(_, m)| m.role == Role::Tool)
        .map(|(i, _)| i)
        .collect()
}

/// Overwrite the `ordinal`-th tool result's content with a deterministic,
/// all-ASCII filler string of exactly `target_len` bytes (same idiom as
/// `reduce_projection.rs::pad_tool_output`).
fn pad_tool_output(session: &mut Session, ordinal: usize, target_len: usize) {
    let idx = tool_indices(session)[ordinal];
    let filler: String = (0..target_len)
        .map(|i| (b'a' + (i % 26) as u8) as char)
        .collect();
    session.messages[idx].content = Some(filler);
}

/// `,`-thousands-separated formatting, matching the stub grammar's style
/// (mirrors the private `reduce::format_commas`).
fn comma(n: usize) -> String {
    let digits = n.to_string();
    let bytes = digits.as_bytes();
    let mut out = String::with_capacity(bytes.len() + bytes.len() / 3);
    for (i, b) in bytes.iter().enumerate() {
        if i > 0 && (bytes.len() - i) % 3 == 0 {
            out.push(',');
        }
        out.push(*b as char);
    }
    out
}

/// Total wire bytes of a message slice — the same "serialized wire bytes"
/// basis D12's token estimator uses.
fn wire_bytes(msgs: &[ChatMessage]) -> usize {
    serde_json::to_string(msgs).unwrap().len()
}

fn temp_dir(tag: &str) -> PathBuf {
    let dir = std::env::temp_dir().join(format!(
        "supercode-reduce-loop-{tag}-{}",
        std::process::id()
    ));
    std::fs::create_dir_all(&dir).unwrap();
    dir
}

// ---------------------------------------------------------------------------
// A7(b): tool_truncation_largest_first_and_reversible
// ---------------------------------------------------------------------------

#[test]
fn tool_truncation_largest_first_and_reversible() {
    let mut session = load_codex();
    pad_tool_output(&mut session, 0, 200_000); // the older tool result
    pad_tool_output(&mut session, 1, 50_000); // the newer tool result

    // ---- one-reduction case: a trigger strictly between 50 KB and 200 KB
    // captures ONLY the largest output as a candidate. ----
    let policy_one = ReductionPolicy {
        tool_output_keep_bytes: 4096,
        tool_output_trigger_bytes: 60_000,
        protect_last_n_tool_results: 0,
        ..ReductionPolicy::default()
    };
    let (_, log_one) = project(&session, &policy_one, &ReductionLog::default());
    assert_eq!(
        log_one.reductions.len(),
        1,
        "only the 200KB output should cross a 60KB trigger"
    );
    match log_one.reductions[0].kind {
        ReductionKind::ToolOutputTruncated { original_bytes, .. } => {
            assert_eq!(
                original_bytes, 200_000,
                "the captured candidate must be the 200KB output"
            )
        }
        ref other => panic!("expected ToolOutputTruncated, got {other:?}"),
    }

    // ---- both-reduced case: trigger=8192 keep=4096 protect_last=0 ----
    let policy = ReductionPolicy {
        tool_output_keep_bytes: 4096,
        tool_output_trigger_bytes: 8192,
        protect_last_n_tool_results: 0,
        ..ReductionPolicy::default()
    };
    let (view, log) = project(&session, &policy, &ReductionLog::default());
    assert_eq!(
        log.reductions.len(),
        2,
        "both padded outputs exceed the 8KB trigger"
    );

    // Largest wins first (#6 "largest wins").
    let sizes: Vec<usize> = log
        .reductions
        .iter()
        .map(|r| match r.kind {
            ReductionKind::ToolOutputTruncated { original_bytes, .. } => original_bytes,
            _ => 0,
        })
        .collect();
    assert_eq!(
        sizes,
        vec![200_000, 50_000],
        "the largest tool output must be reduced first"
    );

    // The placeholder contains the sentinel, the id, and both byte counts
    // (comma-formatted).
    for r in &log.reductions {
        assert!(
            r.placeholder.starts_with(REDUCTION_SENTINEL),
            "{}",
            r.placeholder
        );
        assert!(r.placeholder.contains(&r.id), "{}", r.placeholder);
        let (original_bytes, kept_bytes) = match r.kind {
            ReductionKind::ToolOutputTruncated {
                original_bytes,
                kept_bytes,
            } => (original_bytes, kept_bytes),
            _ => unreachable!(),
        };
        assert!(
            r.placeholder.contains(&comma(original_bytes)),
            "{}",
            r.placeholder
        );
        assert!(
            r.placeholder.contains(&comma(kept_bytes)),
            "{}",
            r.placeholder
        );
    }

    // Both-reduced case inverts to the exact originals (A6).
    let inverted = invert(&view, &log, &session).unwrap();
    assert_eq!(inverted.len(), session.messages.len());
    for (a, b) in inverted.iter().zip(&session.messages) {
        assert_eq!(a.role, b.role);
        assert_eq!(a.content, b.content);
    }

    // Reduced-view total bytes < 10% of full-view bytes for this constructed
    // case.
    let full_bytes = wire_bytes(&session.messages);
    let reduced_bytes = wire_bytes(&view);
    assert!(
        (reduced_bytes as f64) < 0.10 * (full_bytes as f64),
        "reduced {reduced_bytes} should be < 10% of full {full_bytes}"
    );
}

// ---------------------------------------------------------------------------
// A7 loop test (extends A3's `agent_records_full_fidelity_while_capping_view`)
// ---------------------------------------------------------------------------

/// A tool whose output is comfortably over a small `tool_output_trigger_bytes`
/// but well under the agent's `max_tool_output_bytes` safety net — so
/// `cap_tool_output` never intervenes and the FULL output reaches `history`;
/// only the projection layer shrinks it at request-build time.
struct BigOutputTool;
#[async_trait]
impl supercode_harness::tools::Tool for BigOutputTool {
    fn name(&self) -> &str {
        "list_dir"
    }
    fn description(&self) -> &str {
        "x"
    }
    fn parameters(&self) -> serde_json::Value {
        serde_json::json!({"type": "object"})
    }
    async fn execute(
        &self,
        _a: serde_json::Value,
        _c: &supercode_harness::tools::ToolContext,
    ) -> supercode_harness::Result<String> {
        Ok("Q".repeat(20_000))
    }
}

/// Turn 0: call the tool. Turn 1: capture the exact request the model sees
/// (before answering) so the test can inspect the wire body directly.
struct BigOutputThenCapture {
    calls: AtomicUsize,
    captured: Arc<Mutex<Option<Vec<ChatMessage>>>>,
}
#[async_trait]
impl Provider for BigOutputThenCapture {
    async fn complete(
        &self,
        req: &ChatRequest,
        _on_delta: &(dyn for<'a> Fn(&'a str) + Send + Sync),
    ) -> supercode_harness::Result<(ChatMessage, Usage)> {
        let n = self.calls.fetch_add(1, Ordering::SeqCst);
        if n == 0 {
            let call = ChatMessage {
                role: Role::Assistant,
                content: None,
                content_parts: None,
                tool_calls: Some(vec![ToolCall {
                    id: "c1".into(),
                    kind: "function".into(),
                    function: FunctionCall {
                        name: "list_dir".into(),
                        arguments: "{}".into(),
                    },
                }]),
                tool_call_id: None,
                name: None,
                metadata: Default::default(),
            };
            Ok((call, Usage::default()))
        } else {
            *self.captured.lock().unwrap() = Some(req.messages.clone());
            Ok((ChatMessage::assistant("done"), Usage::default()))
        }
    }
}

#[tokio::test]
async fn loop_next_request_carries_reduced_view_not_full_output() {
    let dir = temp_dir("nextreq");
    let sidecar_path = dir.join("sess.sidecar.jsonl");

    // Default `max_tool_output_bytes` (100 KB) never trips for a 20 KB
    // output — it flows uncapped into `history`; the reduction layer's own
    // (much smaller) trigger is what shrinks the NEXT request's view.
    let config = Config::builder().cwd(dir.clone()).build();
    let mut reg = supercode_harness::tools::ToolRegistry::new();
    reg.register(BigOutputTool);
    let captured = Arc::new(Mutex::new(None));
    let mut agent = Agent::with_parts(
        config,
        Box::new(BigOutputThenCapture {
            calls: AtomicUsize::new(0),
            captured: captured.clone(),
        }),
        reg,
    );

    let empty_session = Session::from_claude_code_str("").unwrap();
    let writer = SidecarWriter::create(&sidecar_path, &empty_session).unwrap();
    agent.set_recorder(writer);
    agent.set_reduction_policy(ReductionPolicy {
        tool_output_keep_bytes: 4096,
        tool_output_trigger_bytes: 8192,
        protect_last_n_tool_results: 0,
        ..ReductionPolicy::default()
    });

    let reply = agent.send("go").await.unwrap();
    assert_eq!(reply, "done");

    // (i) `history` kept the FULL, uncapped tool output — cap_tool_output's
    // hard safety net never tripped for 20 KB.
    let full_in_history = agent
        .history()
        .iter()
        .rev()
        .find(|m| m.role == Role::Tool)
        .and_then(|m| m.content.clone())
        .unwrap();
    assert_eq!(full_in_history.len(), 20_000);

    // (ii) the NEXT request's wire body carries the placeholder, not the full
    // output, and no `metadata`/`sc.` bookkeeping ever reaches the wire.
    let captured_msgs = captured.lock().unwrap().clone().unwrap();
    let body = serde_json::to_string(&captured_msgs).unwrap();
    assert!(
        body.contains(REDUCTION_SENTINEL),
        "wire body missing reduction stub: {body}"
    );
    assert!(
        !body.contains(&"Q".repeat(20_000)),
        "wire body must not contain the full tool output"
    );
    assert!(
        !body.contains("\"metadata\""),
        "wire body must never carry the metadata key: {body}"
    );
    assert!(
        !body.contains("sc."),
        "wire body must never carry an sc.* pointer: {body}"
    );

    std::fs::remove_dir_all(&dir).ok();
}

// ---------------------------------------------------------------------------
// A10(b): turn_clearing_reversible_and_supersedes_compaction
// ---------------------------------------------------------------------------

/// Always answers with plain text (no tool calls, so `send` returns after one
/// model turn) — and records every request's message vector it was given, so
/// the test can inspect how the view evolved turn over turn.
struct PlainAnswerCapturing {
    calls: AtomicUsize,
    requests: Arc<Mutex<Vec<Vec<ChatMessage>>>>,
}
#[async_trait]
impl Provider for PlainAnswerCapturing {
    async fn complete(
        &self,
        req: &ChatRequest,
        _on_delta: &(dyn for<'a> Fn(&'a str) + Send + Sync),
    ) -> supercode_harness::Result<(ChatMessage, Usage)> {
        let n = self.calls.fetch_add(1, Ordering::SeqCst);
        self.requests.lock().unwrap().push(req.messages.clone());
        Ok((
            ChatMessage::assistant(format!("reply {n}")),
            Usage::default(),
        ))
    }
}

#[tokio::test]
async fn turn_clearing_reversible_and_supersedes_compaction() {
    let dir = temp_dir("turnclear");
    let sidecar_path = dir.join("sess.sidecar.jsonl");

    let requests = Arc::new(Mutex::new(Vec::new()));
    let config = Config::builder()
        .cwd(dir.clone())
        .compact_after_messages(8)
        .build();
    let mut agent = Agent::with_provider(
        config,
        Box::new(PlainAnswerCapturing {
            calls: AtomicUsize::new(0),
            requests: requests.clone(),
        }),
    );

    let empty_session = Session::from_claude_code_str("").unwrap();
    let writer = SidecarWriter::create(&sidecar_path, &empty_session).unwrap();
    agent.set_recorder(writer);
    // Tool-output knobs irrelevant here (no tool calls in this scenario);
    // only `clear_turns_older_than` (derived by `maybe_compact` from
    // `compact_after_messages`) matters.
    agent.set_reduction_policy(ReductionPolicy::default());

    for i in 0..12 {
        agent.send(format!("turn {i}")).await.unwrap();
    }

    // (ii) `agent.history()` length never decreases — it only ever grows:
    // the synthetic system prompt, plus one (user, assistant) pair per turn.
    assert_eq!(agent.history().len(), 1 + 12 * 2);

    let reqs = requests.lock().unwrap().clone();
    let placeholder_counts: Vec<usize> = reqs
        .iter()
        .map(|msgs| msgs.iter().filter(|m| reduction_id(m).is_some()).count())
        .collect();

    // (i) request views shrink after the trigger and contain exactly one
    // `TurnsCleared` placeholder — never zero-after-triggering, never more
    // than one (it is a singleton reduction, A10).
    assert!(
        placeholder_counts.contains(&1),
        "no request ever carried the TurnsCleared placeholder: {placeholder_counts:?}"
    );
    assert!(
        placeholder_counts.iter().all(|&c| c <= 1),
        "a request carried more than one TurnsCleared placeholder: {placeholder_counts:?}"
    );
    let last_req = reqs.last().unwrap();
    assert!(
        last_req.len() < agent.history().len(),
        "the final request view ({}) should be smaller than full history ({})",
        last_req.len(),
        agent.history().len()
    );

    // (iii) sidecar reload yields all 12 turns (every message, full
    // fidelity) — clearing only ever shrinks the projected VIEW, never
    // `history` or the sidecar.
    let raw = std::fs::read_to_string(&sidecar_path).unwrap();
    let reloaded = Session::from_native_str(&raw).unwrap();
    assert_eq!(
        reloaded.messages.len(),
        agent.history().len() - 1,
        "sidecar must retain every turn, uncleared"
    );

    // (iv) `invert` of the final projected view (reconstructed via
    // `project_messages` over `history[1..]` with the final log) is
    // identical to `history[1..]`.
    let policy = agent.reduction_policy().unwrap().clone();
    let (final_view, final_log) =
        project_messages(&agent.history()[1..], &policy, agent.reduction_log());
    assert_eq!(
        &final_log,
        agent.reduction_log(),
        "re-projecting the final state with its own log must not invent new reductions"
    );
    let inverted = invert(&final_view, &final_log, &reloaded).unwrap();
    assert_eq!(inverted.len(), agent.history().len() - 1);
    for (a, b) in inverted.iter().zip(&agent.history()[1..]) {
        assert_eq!(a.role, b.role);
        assert_eq!(a.content, b.content);
    }

    // (v) with no policy at all, `maybe_compact`'s legacy in-place-surgery
    // behavior is unchanged — covered by the pre-existing
    // `agent_loop.rs::slash_prompt_expansion_and_compaction` test, which
    // still passes byte-identically (D6: this file changes nothing about
    // the no-policy path).

    std::fs::remove_dir_all(&dir).ok();
}

// ---------------------------------------------------------------------------
// Determinism (A5's contract, exercised through the loop-facing entry point)
// ---------------------------------------------------------------------------

#[test]
fn project_messages_is_byte_identical_across_repeated_calls() {
    let mut session = load_codex();
    pad_tool_output(&mut session, 0, 100_000);
    let policy = ReductionPolicy {
        tool_output_keep_bytes: 4096,
        tool_output_trigger_bytes: 8192,
        protect_last_n_tool_results: 0,
        clear_turns_older_than: Some(4),
        ..ReductionPolicy::default()
    };
    let prior = ReductionLog::default();

    let (view1, log1) = project_messages(&session.messages, &policy, &prior);
    let (view2, log2) = project_messages(&session.messages, &policy, &prior);

    let wire1 = serde_json::to_string(&view1).unwrap();
    let wire2 = serde_json::to_string(&view2).unwrap();
    assert_eq!(
        wire1, wire2,
        "identical inputs must produce a byte-identical view"
    );
    assert_eq!(
        log1, log2,
        "identical inputs must produce a byte-identical log"
    );
}

// ---------------------------------------------------------------------------
// A9(b): data_url_image_redacted_and_inverted
// ---------------------------------------------------------------------------

/// Always answers `"described"` with no tool calls — just enough of a
/// provider to let `send_with_images` complete one loop iteration.
struct SaysDescribed;
#[async_trait]
impl Provider for SaysDescribed {
    async fn complete(
        &self,
        _req: &ChatRequest,
        _on_delta: &(dyn for<'a> Fn(&'a str) + Send + Sync),
    ) -> supercode_harness::Result<(ChatMessage, Usage)> {
        Ok((ChatMessage::assistant("described"), Usage::default()))
    }
}

#[tokio::test]
async fn data_url_image_redacted_and_inverted() {
    let dir = temp_dir("images");
    let sidecar_path = dir.join("sess.sidecar.jsonl");

    // A ~400KB `data:` URL image, as SPEC.md A9(b) calls for.
    let big_image = format!("data:image/png;base64,{}", "A".repeat(400_000));

    let config = Config::builder().cwd(dir.clone()).build();
    let mut agent = Agent::with_provider(config, Box::new(SaysDescribed));

    let empty_session = Session::from_claude_code_str("").unwrap();
    let writer = SidecarWriter::create(&sidecar_path, &empty_session).unwrap();
    agent.set_recorder(writer);
    agent.set_reduction_policy(ReductionPolicy {
        redact_images: true,
        ..ReductionPolicy::default()
    });

    let reply = agent
        .send_with_images("caption", std::slice::from_ref(&big_image))
        .await
        .unwrap();
    assert_eq!(reply, "described");

    // Reload the full-fidelity sidecar (A3 write-through) — the ONE canonical
    // model `project`/`invert` operate against.
    let raw = std::fs::read_to_string(&sidecar_path).unwrap();
    let sidecar_session = Session::from_native_str(&raw).unwrap();
    assert_eq!(
        sidecar_session.messages.len(),
        2,
        "sidecar records the multimodal user turn and the assistant reply"
    );
    let user_idx = sidecar_session
        .messages
        .iter()
        .position(|m| m.role == Role::User)
        .unwrap();
    assert!(
        sidecar_session.messages[user_idx].content_parts.is_some(),
        "the recorded user message must keep its full-fidelity image part"
    );

    let policy = agent.reduction_policy().unwrap().clone();
    let (view, log) = project(&sidecar_session, &policy, &ReductionLog::default());

    assert_eq!(
        log.reductions.len(),
        1,
        "exactly one ImageRedacted reduction for the single over-threshold image"
    );
    assert!(matches!(
        log.reductions[0].kind,
        ReductionKind::ImageRedacted { .. }
    ));

    // The reduced message's content_parts carries the caption text part plus
    // the redaction stub — never the original image.
    let parts = view[user_idx].content_parts.as_ref().unwrap();
    assert_eq!(parts.len(), 2, "caption text part + redaction stub");
    assert_eq!(parts[0]["type"], "text");
    assert_eq!(parts[0]["text"], "caption");
    assert_eq!(parts[1]["type"], "text");
    let stub_text = parts[1]["text"].as_str().unwrap();
    assert!(stub_text.starts_with(REDUCTION_SENTINEL), "{stub_text}");
    assert!(stub_text.contains("image/png"), "{stub_text}");

    // No `data:` substring anywhere in the serialized reduced request body
    // (system prompt + projected view — the exact shape `build_request_messages`
    // assembles).
    let mut request_body = vec![agent.history()[0].clone()];
    request_body.extend(view.clone());
    let body = serde_json::to_string(&request_body).unwrap();
    assert!(
        !body.contains("data:"),
        "reduced request body must never carry the raw data: URL: {body}"
    );

    // Invert restores the part byte-identically.
    let inverted = invert(&view, &log, &sidecar_session).unwrap();
    assert_eq!(
        inverted[user_idx].content_parts, sidecar_session.messages[user_idx].content_parts,
        "invert must restore the original image part byte-identically"
    );

    std::fs::remove_dir_all(&dir).ok();
}