awaken-runtime 0.4.0

//! CompactionPlugin, CompactionConfig, and compaction state tracking.

use serde::{Deserialize, Serialize};

use crate::plugins::{Plugin, PluginDescriptor, PluginRegistrar};
use crate::state::{MutationBatch, StateKey, StateKeyOptions};

/// Plugin ID for context compaction.
pub const CONTEXT_COMPACTION_PLUGIN_ID: &str = "context_compaction";

// ---------------------------------------------------------------------------
// CompactionConfig — configurable prompts and thresholds
// ---------------------------------------------------------------------------

/// Configuration for the compaction subsystem.
///
/// Controls summarizer prompts, model selection, and savings thresholds.
/// Stored in `AgentSpec.sections["compaction"]` and read via `PluginConfigKey`.
#[derive(Debug, Clone, Serialize, Deserialize, schemars::JsonSchema)]
pub struct CompactionConfig {
    /// System prompt for the summarizer LLM call.
    pub summarizer_system_prompt: String,
    /// User prompt template. `{messages}` is replaced with the conversation transcript.
    pub summarizer_user_prompt: String,
    /// Maximum tokens for the summary response.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub summary_max_tokens: Option<u32>,
    /// Model to use for summarization (if different from the agent's model).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub summary_model: Option<String>,
    /// Minimum token savings ratio to accept a compaction (0.0-1.0).
    pub min_savings_ratio: f64,
}

impl Default for CompactionConfig {
    fn default() -> Self {
        Self {
            summarizer_system_prompt: "You are a conversation summarizer. Preserve all key facts, decisions, tool results, and action items. Be concise but complete.".into(),
            summarizer_user_prompt: "Summarize the following conversation:\n\n{messages}".into(),
            summary_max_tokens: None,
            summary_model: None,
            min_savings_ratio: 0.3,
        }
    }
}

/// Plugin config key for [`CompactionConfig`].
pub struct CompactionConfigKey;

impl awaken_contract::registry_spec::PluginConfigKey for CompactionConfigKey {
    const KEY: &'static str = "compaction";
    type Config = CompactionConfig;
}

// ---------------------------------------------------------------------------
// Compaction boundary tracking
// ---------------------------------------------------------------------------

/// A recorded compaction boundary — snapshot of a single compaction event.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct CompactionBoundary {
    /// Summary text produced by the compaction pass.
    pub summary: String,
    /// Estimated tokens before compaction (in the compacted range).
    pub pre_tokens: usize,
    /// Estimated tokens after compaction (summary message tokens).
    pub post_tokens: usize,
    /// Timestamp of the compaction event (millis since UNIX epoch).
    pub timestamp_ms: u64,
}

/// Pointer to a single in-flight background compaction pass. Used as a
/// single-flight guard so the runtime never spawns a second compaction
/// while one is still summarizing.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct CompactionInFlight {
    /// Background task id of the running compaction.
    pub task_id: String,
    /// Stable message id of the boundary message at trigger time. Used
    /// to locate the cut point against the current message list when the
    /// summary lands — robust to messages appended during the window.
    pub boundary_message_id: String,
    /// Wall-clock millis when the task was spawned.
    pub started_at_ms: u64,
}

/// Durable state for context compaction tracking.
///
/// Stores a history of compaction boundaries so that load-time trimming
/// and plugin queries can identify already-summarized ranges, plus a
/// single-flight guard for background compaction passes.
#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq, Eq)]
pub struct CompactionState {
    /// Ordered list of compaction boundaries (most recent last).
    pub boundaries: Vec<CompactionBoundary>,
    /// Total number of compaction passes performed.
    pub total_compactions: u64,
    /// Currently running background compaction, if any.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub in_flight: Option<CompactionInFlight>,
}

/// Reducer actions for [`CompactionState`].
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum CompactionAction {
    /// Record a new compaction boundary.
    RecordBoundary(CompactionBoundary),
    /// Mark a background compaction as in flight.
    SetInFlight(CompactionInFlight),
    /// Clear the in-flight marker (called on success and failure).
    ClearInFlight,
    /// Clear all tracked boundaries (e.g. on thread reset).
    Clear,
}

impl CompactionState {
    fn reduce(&mut self, action: CompactionAction) {
        match action {
            CompactionAction::RecordBoundary(boundary) => {
                self.boundaries.push(boundary);
                self.total_compactions += 1;
            }
            CompactionAction::SetInFlight(in_flight) => {
                self.in_flight = Some(in_flight);
            }
            CompactionAction::ClearInFlight => {
                self.in_flight = None;
            }
            CompactionAction::Clear => {
                self.boundaries.clear();
                self.total_compactions = 0;
                self.in_flight = None;
            }
        }
    }

    /// Latest compaction boundary, if any.
    pub fn latest_boundary(&self) -> Option<&CompactionBoundary> {
        self.boundaries.last()
    }

    /// True when a background compaction pass is already running.
    pub fn is_compacting(&self) -> bool {
        self.in_flight.is_some()
    }
}

/// State key for context compaction state.
pub struct CompactionStateKey;

impl StateKey for CompactionStateKey {
    const KEY: &'static str = "__context_compaction";
    type Value = CompactionState;
    type Update = CompactionAction;

    fn apply(value: &mut Self::Value, update: Self::Update) {
        value.reduce(update);
    }
}

// ---------------------------------------------------------------------------
// CompactionPlugin
// ---------------------------------------------------------------------------

/// Plugin that integrates context compaction state into the plugin system.
///
/// Registers the [`CompactionStateKey`] state key so that compaction boundaries
/// are tracked durably and available to other plugins and external observers.
/// Accepts an optional [`CompactionConfig`] for configurable prompts and thresholds.
#[derive(Debug, Clone, Default)]
pub struct CompactionPlugin {
    /// Compaction configuration (prompts, model, thresholds).
    pub config: CompactionConfig,
}

impl CompactionPlugin {
    /// Create with explicit config.
    pub fn new(config: CompactionConfig) -> Self {
        Self { config }
    }
}

impl Plugin for CompactionPlugin {
    fn descriptor(&self) -> PluginDescriptor {
        PluginDescriptor {
            name: CONTEXT_COMPACTION_PLUGIN_ID,
        }
    }

    fn register(&self, registrar: &mut PluginRegistrar) -> Result<(), awaken_contract::StateError> {
        registrar.register_key::<CompactionStateKey>(StateKeyOptions::default())?;
        Ok(())
    }

    fn on_activate(
        &self,
        _agent_spec: &awaken_contract::registry_spec::AgentSpec,
        _patch: &mut MutationBatch,
    ) -> Result<(), awaken_contract::StateError> {
        Ok(())
    }
}

// ---------------------------------------------------------------------------
// ContextTransformPlugin — registers the context truncation request transform
// ---------------------------------------------------------------------------

/// Plugin ID for context truncation transform.
pub const CONTEXT_TRANSFORM_PLUGIN_ID: &str = "context_transform";

/// Plugin that registers the built-in context truncation request transform.
///
/// Wraps a `ContextWindowPolicy` and registers a `ContextTransform` via
/// `register_request_transform()` during plugin registration. This ensures
/// the transform flows through the standard plugin mechanism (ADR-0001)
/// instead of being manually appended post-hoc.
pub struct ContextTransformPlugin {
    policy: awaken_contract::contract::inference::ContextWindowPolicy,
}

impl ContextTransformPlugin {
    pub fn new(policy: awaken_contract::contract::inference::ContextWindowPolicy) -> Self {
        Self { policy }
    }
}

impl Plugin for ContextTransformPlugin {
    fn descriptor(&self) -> PluginDescriptor {
        PluginDescriptor {
            name: CONTEXT_TRANSFORM_PLUGIN_ID,
        }
    }

    fn register(&self, registrar: &mut PluginRegistrar) -> Result<(), awaken_contract::StateError> {
        registrar.register_request_transform(
            CONTEXT_TRANSFORM_PLUGIN_ID,
            super::ContextTransform::new(self.policy.clone()),
        );
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::state::StateStore;
    use awaken_contract::contract::message::Message;

    #[test]
    fn compaction_state_record_boundary() {
        let mut state = CompactionState::default();
        assert_eq!(state.total_compactions, 0);
        assert!(state.boundaries.is_empty());

        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "User asked to implement feature X.".into(),
            pre_tokens: 5000,
            post_tokens: 200,
            timestamp_ms: 1234567890,
        }));

        assert_eq!(state.total_compactions, 1);
        assert_eq!(state.boundaries.len(), 1);
        assert_eq!(
            state.latest_boundary().unwrap().summary,
            "User asked to implement feature X."
        );
    }

    #[test]
    fn compaction_state_multiple_boundaries() {
        let mut state = CompactionState::default();

        for i in 0..3 {
            state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
                summary: format!("summary {i}"),
                pre_tokens: 1000 * (i + 1),
                post_tokens: 100 * (i + 1),
                timestamp_ms: 1000 + i as u64,
            }));
        }

        assert_eq!(state.total_compactions, 3);
        assert_eq!(state.boundaries.len(), 3);
        assert_eq!(state.latest_boundary().unwrap().summary, "summary 2");
    }

    #[test]
    fn compaction_state_clear() {
        let mut state = CompactionState {
            boundaries: vec![CompactionBoundary {
                summary: "old".into(),
                pre_tokens: 100,
                post_tokens: 10,
                timestamp_ms: 1,
            }],
            total_compactions: 1,
            in_flight: None,
        };

        state.reduce(CompactionAction::Clear);
        assert!(state.boundaries.is_empty());
        assert_eq!(state.total_compactions, 0);
    }

    #[test]
    fn compaction_state_latest_boundary_empty() {
        let state = CompactionState::default();
        assert!(state.latest_boundary().is_none());
    }

    #[test]
    fn compaction_state_serde_roundtrip() {
        let state = CompactionState {
            boundaries: vec![
                CompactionBoundary {
                    summary: "first".into(),
                    pre_tokens: 5000,
                    post_tokens: 200,
                    timestamp_ms: 1000,
                },
                CompactionBoundary {
                    summary: "second".into(),
                    pre_tokens: 3000,
                    post_tokens: 150,
                    timestamp_ms: 2000,
                },
            ],
            total_compactions: 2,
            in_flight: None,
        };

        let json = serde_json::to_string(&state).unwrap();
        let parsed: CompactionState = serde_json::from_str(&json).unwrap();
        assert_eq!(parsed, state);
    }

    #[test]
    fn compaction_plugin_registers_key() {
        let store = StateStore::new();
        store.install_plugin(CompactionPlugin::default()).unwrap();
        let registry = store.registry.lock();
        assert!(registry.keys_by_name.contains_key("__context_compaction"));
    }

    #[test]
    fn compaction_plugin_state_via_store() {
        let store = StateStore::new();
        store.install_plugin(CompactionPlugin::default()).unwrap();

        let mut patch = store.begin_mutation();
        patch.update::<CompactionStateKey>(super::super::record_compaction_boundary(
            CompactionBoundary {
                summary: "test summary".into(),
                pre_tokens: 4000,
                post_tokens: 180,
                timestamp_ms: 9999,
            },
        ));
        store.commit(patch).unwrap();

        let state = store.read::<CompactionStateKey>().unwrap();
        assert_eq!(state.total_compactions, 1);
        assert_eq!(state.boundaries[0].summary, "test summary");
    }

    #[test]
    fn record_compaction_boundary_constructor() {
        let action = super::super::record_compaction_boundary(CompactionBoundary {
            summary: "s".into(),
            pre_tokens: 100,
            post_tokens: 10,
            timestamp_ms: 0,
        });
        assert!(matches!(action, CompactionAction::RecordBoundary(_)));
    }

    #[test]
    fn compaction_state_record_then_clear_then_record() {
        let mut state = CompactionState::default();

        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "first".into(),
            pre_tokens: 1000,
            post_tokens: 100,
            timestamp_ms: 1,
        }));
        assert_eq!(state.total_compactions, 1);

        state.reduce(CompactionAction::Clear);
        assert_eq!(state.total_compactions, 0);
        assert!(state.boundaries.is_empty());
        assert!(state.latest_boundary().is_none());

        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "after clear".into(),
            pre_tokens: 2000,
            post_tokens: 150,
            timestamp_ms: 2,
        }));
        assert_eq!(state.total_compactions, 1);
        assert_eq!(state.latest_boundary().unwrap().summary, "after clear");
    }

    #[test]
    fn compaction_state_key_properties() {
        assert_eq!(CompactionStateKey::KEY, "__context_compaction");
    }

    #[test]
    fn compaction_state_key_apply() {
        let mut state = CompactionState::default();
        CompactionStateKey::apply(
            &mut state,
            CompactionAction::RecordBoundary(CompactionBoundary {
                summary: "via apply".into(),
                pre_tokens: 500,
                post_tokens: 50,
                timestamp_ms: 42,
            }),
        );
        assert_eq!(state.total_compactions, 1);
        assert_eq!(state.boundaries[0].summary, "via apply");
    }

    #[test]
    fn compaction_plugin_descriptor_name() {
        let plugin = CompactionPlugin::default();
        assert_eq!(plugin.descriptor().name, CONTEXT_COMPACTION_PLUGIN_ID);
    }

    #[test]
    fn compaction_plugin_new_with_config() {
        let config = CompactionConfig {
            min_savings_ratio: 0.8,
            ..Default::default()
        };
        let plugin = CompactionPlugin::new(config);
        assert!((plugin.config.min_savings_ratio - 0.8).abs() < f64::EPSILON);
    }

    #[test]
    fn compaction_boundary_equality() {
        let a = CompactionBoundary {
            summary: "s".into(),
            pre_tokens: 100,
            post_tokens: 10,
            timestamp_ms: 0,
        };
        let b = a.clone();
        assert_eq!(a, b);
    }

    #[test]
    fn compaction_boundary_serde_roundtrip() {
        let boundary = CompactionBoundary {
            summary: "test summary".into(),
            pre_tokens: 3000,
            post_tokens: 200,
            timestamp_ms: 1234567890,
        };
        let json = serde_json::to_string(&boundary).unwrap();
        let parsed: CompactionBoundary = serde_json::from_str(&json).unwrap();
        assert_eq!(parsed, boundary);
    }

    // -----------------------------------------------------------------------
    // Migrated from uncarve: additional compaction state tests
    // -----------------------------------------------------------------------

    #[test]
    fn compaction_state_default_is_empty() {
        let state = CompactionState::default();
        assert!(state.boundaries.is_empty());
        assert_eq!(state.total_compactions, 0);
        assert!(state.latest_boundary().is_none());
    }

    #[test]
    fn compaction_state_boundary_ordering_preserved() {
        let mut state = CompactionState::default();
        for i in 0..5 {
            state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
                summary: format!("boundary_{i}"),
                pre_tokens: 1000,
                post_tokens: 100,
                timestamp_ms: i as u64,
            }));
        }
        assert_eq!(state.boundaries.len(), 5);
        assert_eq!(state.total_compactions, 5);
        for (i, b) in state.boundaries.iter().enumerate() {
            assert_eq!(b.summary, format!("boundary_{i}"));
            assert_eq!(b.timestamp_ms, i as u64);
        }
    }

    #[test]
    fn compaction_state_clear_twice_is_idempotent() {
        let mut state = CompactionState::default();
        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "s".into(),
            pre_tokens: 1,
            post_tokens: 1,
            timestamp_ms: 0,
        }));
        state.reduce(CompactionAction::Clear);
        state.reduce(CompactionAction::Clear);
        assert!(state.boundaries.is_empty());
        assert_eq!(state.total_compactions, 0);
    }

    #[test]
    fn compaction_config_default_has_sane_values() {
        let config = CompactionConfig::default();
        assert!(!config.summarizer_system_prompt.is_empty());
        assert!(config.summarizer_user_prompt.contains("{messages}"));
        assert!(config.min_savings_ratio > 0.0);
        assert!(config.min_savings_ratio < 1.0);
        assert!(config.summary_max_tokens.is_none());
        assert!(config.summary_model.is_none());
    }

    #[test]
    fn compaction_config_serde_roundtrip() {
        let config = CompactionConfig {
            summarizer_system_prompt: "custom system".into(),
            summarizer_user_prompt: "custom user: {messages}".into(),
            summary_max_tokens: Some(512),
            summary_model: Some("claude-3-haiku".into()),
            min_savings_ratio: 0.5,
        };
        let json = serde_json::to_string(&config).unwrap();
        let parsed: CompactionConfig = serde_json::from_str(&json).unwrap();
        assert_eq!(
            parsed.summarizer_system_prompt,
            config.summarizer_system_prompt
        );
        assert_eq!(parsed.summary_max_tokens, Some(512));
        assert_eq!(parsed.summary_model.as_deref(), Some("claude-3-haiku"));
    }

    #[test]
    fn compaction_state_pre_post_tokens_preserved() {
        let mut state = CompactionState::default();
        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "test".into(),
            pre_tokens: 10_000,
            post_tokens: 500,
            timestamp_ms: 99,
        }));
        let b = state.latest_boundary().unwrap();
        assert_eq!(b.pre_tokens, 10_000);
        assert_eq!(b.post_tokens, 500);
        assert_eq!(b.timestamp_ms, 99);
    }

    #[test]
    fn context_transform_plugin_descriptor_name() {
        let policy = awaken_contract::contract::inference::ContextWindowPolicy::default();
        let plugin = ContextTransformPlugin::new(policy);
        assert_eq!(plugin.descriptor().name, CONTEXT_TRANSFORM_PLUGIN_ID);
    }

    // -----------------------------------------------------------------------
    // Additional compaction tests
    // -----------------------------------------------------------------------

    #[test]
    fn compaction_fires_at_threshold() {
        // Verify savings ratio check: only accept compaction when savings >= min_savings_ratio
        let config = CompactionConfig {
            min_savings_ratio: 0.5,
            ..Default::default()
        };
        let boundary_good = CompactionBoundary {
            summary: "good".into(),
            pre_tokens: 1000,
            post_tokens: 400, // 60% savings > 50% threshold
            timestamp_ms: 1,
        };
        let savings_good =
            1.0 - (boundary_good.post_tokens as f64 / boundary_good.pre_tokens as f64);
        assert!(
            savings_good >= config.min_savings_ratio,
            "60% savings should meet 50% threshold"
        );

        let boundary_bad = CompactionBoundary {
            summary: "bad".into(),
            pre_tokens: 1000,
            post_tokens: 600, // 40% savings < 50% threshold
            timestamp_ms: 2,
        };
        let savings_bad = 1.0 - (boundary_bad.post_tokens as f64 / boundary_bad.pre_tokens as f64);
        assert!(
            savings_bad < config.min_savings_ratio,
            "40% savings should not meet 50% threshold"
        );
    }

    #[test]
    fn compaction_state_tracks_across_multiple_rounds() {
        let mut state = CompactionState::default();
        // Simulate 5 compaction rounds with increasing pre-token counts
        for round in 1..=5u64 {
            state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
                summary: format!("round {round}"),
                pre_tokens: 1000 * round as usize,
                post_tokens: 100 * round as usize,
                timestamp_ms: round * 1000,
            }));
            assert_eq!(state.total_compactions, round);
            assert_eq!(state.boundaries.len(), round as usize);
        }
        // Latest boundary should be the last round
        assert_eq!(state.latest_boundary().unwrap().summary, "round 5");
        assert_eq!(state.latest_boundary().unwrap().pre_tokens, 5000);
    }

    #[test]
    fn compaction_config_serialization_omits_none_fields() {
        let config = CompactionConfig::default();
        let json = serde_json::to_value(&config).unwrap();
        // summary_max_tokens and summary_model are None, should be omitted via skip_serializing_if
        assert!(
            !json.as_object().unwrap().contains_key("summary_max_tokens"),
            "None fields should be omitted"
        );
        assert!(
            !json.as_object().unwrap().contains_key("summary_model"),
            "None fields should be omitted"
        );
    }

    #[test]
    fn compaction_config_serialization_includes_some_fields() {
        let config = CompactionConfig {
            summary_max_tokens: Some(1024),
            summary_model: Some("claude-3-sonnet".into()),
            ..Default::default()
        };
        let json = serde_json::to_value(&config).unwrap();
        assert_eq!(json["summary_max_tokens"], 1024);
        assert_eq!(json["summary_model"], "claude-3-sonnet");
    }

    #[test]
    fn compaction_with_tool_messages_records_correctly() {
        // Simulate compaction that includes tool messages in the summarized range
        let store = StateStore::new();
        store.install_plugin(CompactionPlugin::default()).unwrap();

        // Record a boundary representing a range that included tool messages
        let mut patch = store.begin_mutation();
        patch.update::<CompactionStateKey>(super::super::record_compaction_boundary(
            CompactionBoundary {
                summary: "User asked to search files. Tool search returned 3 results. Assistant presented findings.".into(),
                pre_tokens: 8000,
                post_tokens: 200,
                timestamp_ms: 1000,
            },
        ));
        store.commit(patch).unwrap();

        let state = store.read::<CompactionStateKey>().unwrap();
        assert_eq!(state.total_compactions, 1);
        assert!(state.boundaries[0].summary.contains("Tool search"));
        assert_eq!(state.boundaries[0].pre_tokens, 8000);
    }

    #[test]
    fn context_transform_plugin_registers_transform() {
        use crate::plugins::PluginRegistrar;
        let policy = awaken_contract::contract::inference::ContextWindowPolicy::default();
        let plugin = ContextTransformPlugin::new(policy);
        let mut registrar = PluginRegistrar::new();
        plugin.register(&mut registrar).unwrap();
        assert_eq!(
            registrar.request_transforms.len(),
            1,
            "should have registered one transform"
        );
        assert_eq!(
            registrar.request_transforms[0].plugin_id,
            CONTEXT_TRANSFORM_PLUGIN_ID
        );
    }

    #[test]
    fn transform_ordering_compaction_then_context() {
        use crate::plugins::PluginRegistrar;
        // Compaction plugin should register no transforms
        let mut reg_compaction = PluginRegistrar::new();
        CompactionPlugin::default()
            .register(&mut reg_compaction)
            .unwrap();
        assert!(
            reg_compaction.request_transforms.is_empty(),
            "CompactionPlugin should not register request transforms"
        );
        // ContextTransformPlugin should register exactly one transform
        let policy = awaken_contract::contract::inference::ContextWindowPolicy::default();
        let mut reg_transform = PluginRegistrar::new();
        ContextTransformPlugin::new(policy)
            .register(&mut reg_transform)
            .unwrap();
        assert_eq!(reg_transform.request_transforms.len(), 1);
    }

    #[test]
    fn token_count_estimation_for_various_content_types() {
        use awaken_contract::contract::transform::estimate_message_tokens;

        // Text message
        let text_msg = Message::user("Hello, this is a test message with some content.");
        let text_tokens = estimate_message_tokens(&text_msg);
        assert!(
            text_tokens > 4,
            "text message should have tokens beyond overhead"
        );

        // Empty content message
        let empty_msg = Message::user("");
        let empty_tokens = estimate_message_tokens(&empty_msg);
        assert_eq!(
            empty_tokens, 4,
            "empty message should have only overhead tokens"
        );

        // Very long message
        let long_msg = Message::user("x".repeat(4000));
        let long_tokens = estimate_message_tokens(&long_msg);
        assert!(
            long_tokens >= 1000,
            "4000-char message should estimate >= 1000 tokens, got {long_tokens}"
        );
    }

    #[test]
    fn enable_prompt_cache_flag_in_policy() {
        let policy_cached = awaken_contract::contract::inference::ContextWindowPolicy {
            enable_prompt_cache: true,
            ..Default::default()
        };
        assert!(policy_cached.enable_prompt_cache);

        let policy_uncached = awaken_contract::contract::inference::ContextWindowPolicy {
            enable_prompt_cache: false,
            ..Default::default()
        };
        assert!(!policy_uncached.enable_prompt_cache);

        // Both should create valid transform plugins
        let _ = ContextTransformPlugin::new(policy_cached);
        let _ = ContextTransformPlugin::new(policy_uncached);
    }

    #[test]
    fn autocompact_threshold_check() {
        use awaken_contract::contract::transform::estimate_tokens;

        let policy_with_threshold = awaken_contract::contract::inference::ContextWindowPolicy {
            autocompact_threshold: Some(500),
            ..Default::default()
        };

        // Simulate checking if messages exceed autocompact threshold
        let messages = vec![Message::user("short"), Message::assistant("reply")];
        let total = estimate_tokens(&messages);
        assert!(
            total < policy_with_threshold.autocompact_threshold.unwrap(),
            "short conversation should be under threshold"
        );

        // Longer conversation should exceed threshold
        let long_messages: Vec<Message> = (0..100)
            .map(|i| Message::user(format!("message {i} with some filler text to add tokens")))
            .collect();
        let long_total = estimate_tokens(&long_messages);
        assert!(
            long_total > policy_with_threshold.autocompact_threshold.unwrap(),
            "100-message conversation should exceed threshold of 500, got {long_total}"
        );
    }

    #[test]
    fn in_flight_set_and_clear_round_trip() {
        let mut state = CompactionState::default();
        assert!(!state.is_compacting());

        state.reduce(CompactionAction::SetInFlight(CompactionInFlight {
            task_id: "bg_42".into(),
            boundary_message_id: "01HZ-msg-01".into(),
            started_at_ms: 100,
        }));
        let live = state.in_flight.as_ref().expect("in-flight set");
        assert_eq!(live.task_id, "bg_42");
        assert_eq!(live.boundary_message_id, "01HZ-msg-01");
        assert!(state.is_compacting());

        state.reduce(CompactionAction::ClearInFlight);
        assert!(state.in_flight.is_none());
        assert!(!state.is_compacting());
    }

    #[test]
    fn clear_action_resets_in_flight_too() {
        let mut state = CompactionState::default();
        state.reduce(CompactionAction::SetInFlight(CompactionInFlight {
            task_id: "bg_1".into(),
            boundary_message_id: "msg-id".into(),
            started_at_ms: 1,
        }));
        state.reduce(CompactionAction::Clear);
        assert!(state.in_flight.is_none());
        assert!(state.boundaries.is_empty());
    }

    #[test]
    fn record_boundary_does_not_touch_in_flight() {
        let mut state = CompactionState::default();
        state.reduce(CompactionAction::SetInFlight(CompactionInFlight {
            task_id: "bg_99".into(),
            boundary_message_id: "msg".into(),
            started_at_ms: 1,
        }));
        state.reduce(CompactionAction::RecordBoundary(CompactionBoundary {
            summary: "s".into(),
            pre_tokens: 10,
            post_tokens: 1,
            timestamp_ms: 2,
        }));
        // RecordBoundary alone does not clear the marker — the inbox
        // event router is responsible for the explicit ClearInFlight.
        assert!(state.is_compacting());
        assert_eq!(state.boundaries.len(), 1);
    }

    #[test]
    fn compaction_action_serde_roundtrip() {
        let actions = vec![
            CompactionAction::RecordBoundary(CompactionBoundary {
                summary: "s".into(),
                pre_tokens: 1,
                post_tokens: 1,
                timestamp_ms: 0,
            }),
            CompactionAction::Clear,
        ];
        for action in actions {
            let json = serde_json::to_string(&action).unwrap();
            let parsed: CompactionAction = serde_json::from_str(&json).unwrap();
            // Verify the action type roundtrips
            match (&action, &parsed) {
                (CompactionAction::Clear, CompactionAction::Clear) => {}
                (CompactionAction::RecordBoundary(a), CompactionAction::RecordBoundary(b)) => {
                    assert_eq!(a.summary, b.summary);
                }
                _ => panic!("action type mismatch after serde roundtrip"),
            }
        }
    }
}