rig-memvid 0.4.0

//! [`MemvidPersistHook`]: a [`PromptHook`] that persists every turn of an
//! agent conversation into a [`MemvidStore`].

use std::marker::PhantomData;
use std::sync::Arc;

use memvid_core::{MemoryCard, MemoryCardBuilder, PutOptions};
use rig::{
    agent::{HookAction, PromptHook},
    completion::{CompletionModel, CompletionResponse, Message},
};

use crate::store::MemvidStore;

/// A function that decides what (if anything) to persist for a single
/// message. Returning `None` skips the message.
///
/// Returning `Some("")` is treated identically to `None`: empty payloads
/// are never written to the archive.
pub type WriteTransform = Arc<dyn Fn(&Message) -> Option<String> + Send + Sync + 'static>;

/// Strategy for what to write into the memvid archive on each turn.
#[derive(Clone, Default)]
pub enum WritePolicy {
    /// Do not persist anything. The hook becomes a no-op (useful for toggling
    /// memory at runtime without removing the hook).
    Disabled,
    /// Persist the verbatim text of every user prompt and assistant response.
    #[default]
    Raw,
    /// Apply the supplied transform to each message and persist its result
    /// (or nothing, if the transform returns `None`).
    ///
    /// This is the extension point for caller-defined summarisation, PII
    /// redaction, or selective filtering.
    Custom(WriteTransform),
}

impl std::fmt::Debug for WritePolicy {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Disabled => f.write_str("WritePolicy::Disabled"),
            Self::Raw => f.write_str("WritePolicy::Raw"),
            Self::Custom(_) => f.write_str("WritePolicy::Custom(<fn>)"),
        }
    }
}

/// Callback type for [`WriteFailure::Custom`]. Receives the failing
/// phase plus the underlying [`crate::MemvidError`] and returns a
/// [`WriteFailureAction`] telling the hook whether to keep going or
/// halt the agent.
pub type WriteFailureCallback =
    Arc<dyn Fn(WriteFailurePhase, &crate::MemvidError) -> WriteFailureAction + Send + Sync>;

/// What the [`MemvidPersistHook`] does when a frame fails to write.
///
/// Defaults to [`WriteFailure::Warn`] so existing behaviour is preserved:
/// the failure is logged via `tracing::warn!` and the turn continues. Operators
/// who would rather halt the agent than silently lose memory writes can
/// switch to [`WriteFailure::Halt`]; advanced callers can install a
/// [`WriteFailure::Custom`] callback (e.g. to update a counter, page on
/// an SLO breach, or fall back to a sidecar log).
#[derive(Clone, Default)]
pub enum WriteFailure {
    /// Log the failure at `WARN` and continue the turn. Default — matches
    /// pre-0.2 behaviour.
    #[default]
    Warn,
    /// Log the failure at `ERROR`, emit a `tracing` event, and signal the
    /// agent to stop via `HookAction::Terminate` on the next return path.
    /// Useful when the agent's value is bounded by durable memory.
    Halt,
    /// Run a caller-provided callback with the failure phase and error.
    /// Returning [`WriteFailureAction::Continue`] keeps the turn alive;
    /// [`WriteFailureAction::Halt`] stops the agent.
    Custom(WriteFailureCallback),
}

impl std::fmt::Debug for WriteFailure {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Warn => f.write_str("WriteFailure::Warn"),
            Self::Halt => f.write_str("WriteFailure::Halt"),
            Self::Custom(_) => f.write_str("WriteFailure::Custom(<fn>)"),
        }
    }
}

/// Which stage of frame persistence raised the error.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum WriteFailurePhase {
    /// `put_text_uncommitted` failed; the frame text was not appended.
    Put,
    /// `put_memory_card` failed; the structured card was not appended.
    PutCard,
    /// `commit` failed; previously appended frames may or may not be flushed
    /// depending on the underlying memvid error.
    Commit,
}

/// Decision returned by a [`WriteFailure::Custom`] callback.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
#[non_exhaustive]
pub enum WriteFailureAction {
    /// Keep processing the turn (matches the default warn-and-continue path).
    Continue,
    /// Halt the agent on the next return point.
    Halt,
}

/// Configuration for [`MemvidPersistHook`].
///
/// `MemoryConfig` is `#[non_exhaustive]` so new fields can be added without a
/// SemVer-major bump; build instances through [`MemoryConfig::default`] +
/// field updates, or through [`MemoryConfig::builder`] for a fluent shape.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct MemoryConfig {
    /// What to persist on each turn.
    pub policy: WritePolicy,
    /// If `true`, call `commit()` after every turn so the new frames are
    /// immediately searchable. If `false`, the caller is responsible for
    /// committing periodically.
    pub commit_each_turn: bool,
    /// Tags applied to every persisted frame, useful for later filtering.
    pub default_tags: Vec<String>,
    /// Logical scope written into the frame's URI prefix. When set, every
    /// frame produced by this hook is stored with `PutOptions.uri = Some(scope)`,
    /// which makes `MemvidFilter::eq("scope", scope)` match those
    /// frames at query time (memvid's `scope` is a URI prefix filter).
    pub scope: Option<String>,
    /// Stable identity for the human side of the conversation.
    ///
    /// When set, user turns are lightly rewritten before memvid sees
    /// them so first-person pronouns resolve to this principal. For
    /// example, with `principal = Some("Alice".into())`, `I like
    /// espresso` is persisted as `Alice likes espresso`. This improves
    /// memvid's entity / slot / value extraction without requiring an
    /// LLM or a new runtime dependency.
    pub principal: Option<String>,
    /// If `true`, persist assistant responses as well as user turns.
    ///
    /// Defaults to `true` to preserve the full conversation transcript.
    /// Set to `false` when the archive is primarily used for user profile
    /// memory and assistant paraphrases would add noisy duplicate cards.
    pub persist_assistant: bool,
    /// Add small deterministic cards for principal-bound user turns when
    /// memvid's built-in triplet extractor misses common user-profile or
    /// relationship facts.
    ///
    /// Currently covers allergy / avoidance statements and simple
    /// manager / reporting statements after [`Self::principal`] has
    /// bound first-person pronouns to the stable entity. Defaults to
    /// `true`; it is a no-op when `principal` is `None`.
    pub supplemental_profile_cards: bool,
    /// Run memvid's auto-tagger over each persisted frame to attach
    /// extracted entity / topic tags. Defaults to `true`, mirroring
    /// [`memvid_core::PutOptions::default`].
    pub auto_tag: bool,
    /// Run memvid's date extractor over each persisted frame so dates
    /// mentioned in conversation become queryable. Defaults to `true`.
    pub extract_dates: bool,
    /// Extract Subject-Predicate-Object triplets from each persisted
    /// frame and store them as [`memvid_core::MemoryCard`]s on the
    /// memories track. Cards become queryable through
    /// [`crate::MemvidStore::entity_memories`],
    /// [`crate::MemvidStore::current_memory`],
    /// [`crate::MemvidStore::entity_preferences`], and the rest of the
    /// memory-card surface. Defaults to `true`.
    pub extract_triplets: bool,
    /// Conversation ID stamped on `rig_tap` events emitted by this
    /// hook (`memory.frame_written`). When `None`, the hook falls back to
    /// [`Self::scope`] and finally to `"default"` so existing consumers
    /// keep working, but explicitly setting this field is preferred: it
    /// decouples telemetry correlation from memvid's URI-prefix scope.
    /// No effect when the `observe` feature is off.
    pub observe_conversation_id: Option<String>,
    /// What to do when a frame fails to write. Defaults to
    /// [`WriteFailure::Warn`] (log + continue) to preserve pre-0.2
    /// behaviour. Switch to [`WriteFailure::Halt`] when durable memory is a
    /// hard requirement, or supply a [`WriteFailure::Custom`] callback to
    /// route the failure into your own metrics / alerting.
    pub on_write_failure: WriteFailure,
    /// Whether to rewrite first-person pronouns in user turns into the
    /// configured [`Self::principal`] (English-only heuristic). Defaults
    /// to `true`, but the rewrite is also a no-op when `principal` is
    /// `None`. Set to `false` to disable the heuristic entirely (e.g.
    /// for non-English transcripts or when callers already canonicalise
    /// text upstream).
    ///
    /// The rewrite also short-circuits on a per-text basis when the
    /// turn contains a triple-backtick code fence or a balanced
    /// double-quoted span containing the standalone token `I`; both are
    /// strong signals that the literal `I` is quoted speech or code and
    /// must not be rewritten.
    pub rewrite_principal_pronouns: bool,
}

impl Default for MemoryConfig {
    fn default() -> Self {
        Self {
            policy: WritePolicy::default(),
            commit_each_turn: true,
            default_tags: Vec::new(),
            scope: None,
            principal: None,
            persist_assistant: true,
            supplemental_profile_cards: true,
            auto_tag: true,
            extract_dates: true,
            extract_triplets: true,
            observe_conversation_id: None,
            on_write_failure: WriteFailure::default(),
            rewrite_principal_pronouns: true,
        }
    }
}

impl MemoryConfig {
    /// Start a [`MemoryConfigBuilder`] for fluent construction. Equivalent
    /// to `MemoryConfigBuilder::default()` but easier to discover.
    pub fn builder() -> MemoryConfigBuilder {
        MemoryConfigBuilder::default()
    }
}

/// Fluent builder for [`MemoryConfig`].
///
/// `MemoryConfig` is `#[non_exhaustive]` to keep adding fields
/// SemVer-additive. Prefer this builder over struct-literal construction
/// so future fields land transparently.
///
/// ```rust,no_run
/// use rig_memvid::{MemoryConfig, WritePolicy};
/// let config = MemoryConfig::builder()
///     .policy(WritePolicy::Raw)
///     .commit_each_turn(false)
///     .principal(Some("Alice".into()))
///     .persist_assistant(false)
///     .build();
/// # let _ = config;
/// ```
#[derive(Clone, Debug, Default)]
pub struct MemoryConfigBuilder {
    config: MemoryConfig,
}

impl MemoryConfigBuilder {
    /// Set the [`WritePolicy`].
    pub fn policy(mut self, policy: WritePolicy) -> Self {
        self.config.policy = policy;
        self
    }
    /// Whether to `commit()` after every turn.
    pub fn commit_each_turn(mut self, commit_each_turn: bool) -> Self {
        self.config.commit_each_turn = commit_each_turn;
        self
    }
    /// Tags applied to every persisted frame.
    pub fn default_tags(mut self, tags: Vec<String>) -> Self {
        self.config.default_tags = tags;
        self
    }
    /// Logical scope (URI prefix) for every persisted frame.
    pub fn scope(mut self, scope: Option<String>) -> Self {
        self.config.scope = scope;
        self
    }
    /// Stable identity for the human side of the conversation.
    pub fn principal(mut self, principal: Option<String>) -> Self {
        self.config.principal = principal;
        self
    }
    /// Whether to persist assistant turns.
    pub fn persist_assistant(mut self, persist_assistant: bool) -> Self {
        self.config.persist_assistant = persist_assistant;
        self
    }
    /// Whether to add deterministic supplemental profile / relationship cards.
    pub fn supplemental_profile_cards(mut self, on: bool) -> Self {
        self.config.supplemental_profile_cards = on;
        self
    }
    /// Run memvid's auto-tagger over each persisted frame.
    pub fn auto_tag(mut self, on: bool) -> Self {
        self.config.auto_tag = on;
        self
    }
    /// Run memvid's date extractor over each persisted frame.
    pub fn extract_dates(mut self, on: bool) -> Self {
        self.config.extract_dates = on;
        self
    }
    /// Run memvid's triplet extractor over each persisted frame.
    pub fn extract_triplets(mut self, on: bool) -> Self {
        self.config.extract_triplets = on;
        self
    }
    /// Telemetry conversation ID for the `observe` feature.
    pub fn observe_conversation_id(mut self, id: Option<String>) -> Self {
        self.config.observe_conversation_id = id;
        self
    }
    /// Policy for frame-write failures.
    pub fn on_write_failure(mut self, policy: WriteFailure) -> Self {
        self.config.on_write_failure = policy;
        self
    }
    /// Enable or disable the English-only principal-pronoun rewrite.
    pub fn rewrite_principal_pronouns(mut self, on: bool) -> Self {
        self.config.rewrite_principal_pronouns = on;
        self
    }
    /// Finalise the builder and return a [`MemoryConfig`].
    pub fn build(self) -> MemoryConfig {
        self.config
    }
}

/// Hook that records every user prompt and assistant response into a
/// [`MemvidStore`].
///
/// The hook is generic over the [`CompletionModel`] so the same store can be
/// shared between agents that use different providers.
pub struct MemvidPersistHook<M> {
    store: MemvidStore,
    config: MemoryConfig,
    /// Set by [`MemvidPersistHook::write`] when [`WriteFailure::Halt`]
    /// (or a [`WriteFailure::Custom`] callback returning
    /// [`WriteFailureAction::Halt`]) fires. The next call into a
    /// `PromptHook` method observes this flag and returns
    /// [`HookAction::terminate`] so the agent loop terminates with the
    /// failure surfaced through `tracing::error!`.
    halt: Arc<std::sync::atomic::AtomicBool>,
    _model: PhantomData<fn() -> M>,
}

impl<M> Clone for MemvidPersistHook<M> {
    fn clone(&self) -> Self {
        Self {
            store: self.store.clone(),
            config: self.config.clone(),
            halt: self.halt.clone(),
            _model: PhantomData,
        }
    }
}

impl<M> std::fmt::Debug for MemvidPersistHook<M> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("MemvidPersistHook")
            .field("config", &self.config)
            .finish_non_exhaustive()
    }
}

impl<M> MemvidPersistHook<M> {
    /// Create a new hook persisting into `store` according to `config`.
    pub fn new(store: MemvidStore, config: MemoryConfig) -> Self {
        Self {
            store,
            config,
            halt: Arc::new(std::sync::atomic::AtomicBool::new(false)),
            _model: PhantomData,
        }
    }

    /// Convenience: build a hook with the default [`MemoryConfig`]
    /// ([`WritePolicy::Raw`], `commit_each_turn = true`).
    pub fn with_defaults(store: MemvidStore) -> Self {
        Self::new(store, MemoryConfig::default())
    }

    fn render(&self, msg: &Message) -> Option<String> {
        match &self.config.policy {
            WritePolicy::Disabled => None,
            WritePolicy::Raw => render_message_text(msg),
            WritePolicy::Custom(f) => f(msg),
        }
    }

    fn put_options(&self, chat_role: &str) -> PutOptions {
        let mut opts = PutOptions {
            tags: self.config.default_tags.clone(),
            auto_tag: self.config.auto_tag,
            extract_dates: self.config.extract_dates,
            extract_triplets: self.config.extract_triplets,
            ..PutOptions::default()
        };
        opts.extra_metadata
            .insert("chat_role".into(), chat_role.into());
        if let Some(scope) = self.config.scope.as_deref() {
            // Memvid's `scope` search filter matches against frame URIs by
            // prefix, so attach the scope as the URI. Also stash it under
            // `extra_metadata["scope"]` for ergonomic introspection by
            // tools that walk frames directly.
            opts.uri = Some(scope.to_string());
            opts.extra_metadata.insert("scope".into(), scope.into());
        }
        opts
    }

    fn write(&self, text: &str, chat_role: &str) {
        if text.is_empty() {
            return;
        }
        let text = if chat_role == "user" && self.config.rewrite_principal_pronouns {
            self.config
                .principal
                .as_deref()
                .map(|principal| bind_principal(text, principal))
                .unwrap_or_else(|| text.to_string())
        } else {
            text.to_string()
        };
        let opts = self.put_options(chat_role);
        let scope = self.config.scope.clone();
        let frame_id = match self.store.put_text_uncommitted(&text, opts) {
            Ok(frame_id) => frame_id,
            Err(err) => {
                self.handle_write_failure(WriteFailurePhase::Put, chat_role, &err);
                return;
            }
        };
        #[cfg(feature = "observe")]
        rig_tap::emit_kind(
            self.config
                .observe_conversation_id
                .as_deref()
                .or(scope.as_deref())
                .unwrap_or("default"),
            rig_tap::EventKind::MemoryFrameWritten {
                frame_kind: "turn".to_string(),
                // memvid does not expose a cheap cumulative frame count
                // from this hot path.
                frame_count_after: None,
                bytes_written: text.len(),
            },
        );

        if chat_role == "user"
            && self.config.supplemental_profile_cards
            && let Some(principal) = self.config.principal.as_deref()
        {
            for card in supplemental_memory_cards(&text, principal, frame_id, scope.clone()) {
                if let Err(err) = self.store.put_memory_card(card) {
                    self.handle_write_failure(WriteFailurePhase::PutCard, chat_role, &err);
                }
            }
        }

        if self.config.commit_each_turn
            && let Err(err) = self.store.commit()
        {
            self.handle_write_failure(WriteFailurePhase::Commit, chat_role, &err);
        }
    }

    /// Apply the configured [`WriteFailure`] policy to a single failure.
    /// Always logs through `tracing`; may also flip `self.halt` so the next
    /// trait method returns [`HookAction::terminate`].
    fn handle_write_failure(
        &self,
        phase: WriteFailurePhase,
        chat_role: &str,
        err: &crate::MemvidError,
    ) {
        let phase_str = match phase {
            WriteFailurePhase::Put => "put",
            WriteFailurePhase::PutCard => "put_card",
            WriteFailurePhase::Commit => "commit",
        };
        match &self.config.on_write_failure {
            WriteFailure::Warn => {
                tracing::warn!(
                    target: "rig_memvid::hook",
                    error = %err,
                    role = chat_role,
                    phase = phase_str,
                    "failed to persist into memvid",
                );
            }
            WriteFailure::Halt => {
                tracing::error!(
                    target: "rig_memvid::hook",
                    error = %err,
                    role = chat_role,
                    phase = phase_str,
                    "failed to persist into memvid; halting agent per WriteFailure::Halt",
                );
                self.halt.store(true, std::sync::atomic::Ordering::SeqCst);
            }
            WriteFailure::Custom(callback) => {
                let action = (callback)(phase, err);
                if matches!(action, WriteFailureAction::Halt) {
                    tracing::error!(
                        target: "rig_memvid::hook",
                        error = %err,
                        role = chat_role,
                        phase = phase_str,
                        "failed to persist into memvid; halting agent per WriteFailure::Custom",
                    );
                    self.halt.store(true, std::sync::atomic::Ordering::SeqCst);
                } else {
                    tracing::warn!(
                        target: "rig_memvid::hook",
                        error = %err,
                        role = chat_role,
                        phase = phase_str,
                        "failed to persist into memvid (Custom policy: continue)",
                    );
                }
            }
        }
    }

    /// Whether the hook has been asked to halt the agent (latched after a
    /// write failure under [`WriteFailure::Halt`] or a Custom callback
    /// returning [`WriteFailureAction::Halt`]). Visible to tests and to the
    /// `PromptHook` impl below.
    fn should_halt(&self) -> bool {
        self.halt.load(std::sync::atomic::Ordering::SeqCst)
    }
}

fn supplemental_memory_cards(
    text: &str,
    principal: &str,
    frame_id: u64,
    source_uri: Option<String>,
) -> Vec<MemoryCard> {
    let mut cards = Vec::new();
    if let Some(value) = allergy_value(text)
        && let Some(card) = profile_card(
            &principal.to_lowercase(),
            "allergy",
            &value,
            frame_id,
            source_uri.clone(),
        )
    {
        cards.push(card);
    }
    cards.extend(relationship_cards(text, principal, frame_id, source_uri));
    cards
}

fn profile_card(
    entity: &str,
    slot: &str,
    value: &str,
    frame_id: u64,
    source_uri: Option<String>,
) -> Option<MemoryCard> {
    MemoryCardBuilder::new()
        .profile()
        .entity(normalize_entity(entity))
        .slot(slot)
        .value(value.trim())
        .source(frame_id, source_uri)
        .engine("rig-memvid:principal-rules", "2")
        .confidence(1.0)
        .build(0)
        .ok()
}

fn relationship_card(
    entity: &str,
    slot: &str,
    value: &str,
    frame_id: u64,
    source_uri: Option<String>,
) -> Option<MemoryCard> {
    MemoryCardBuilder::new()
        .relationship()
        .entity(normalize_entity(entity))
        .slot(slot)
        .value(value.trim())
        .source(frame_id, source_uri)
        .engine("rig-memvid:principal-rules", "2")
        .confidence(1.0)
        .build(0)
        .ok()
}

fn fact_card(
    entity: &str,
    slot: &str,
    value: &str,
    frame_id: u64,
    source_uri: Option<String>,
) -> Option<MemoryCard> {
    MemoryCardBuilder::new()
        .fact()
        .entity(normalize_entity(entity))
        .slot(slot)
        .value(value.trim())
        .source(frame_id, source_uri)
        .engine("rig-memvid:principal-rules", "2")
        .confidence(1.0)
        .build(0)
        .ok()
}

fn relationship_cards(
    text: &str,
    principal: &str,
    frame_id: u64,
    source_uri: Option<String>,
) -> Vec<MemoryCard> {
    let mut cards = Vec::new();
    let Some(manager) = manager_subject(text, principal) else {
        return cards;
    };

    if let Some(card) =
        relationship_card(principal, "manager", &manager, frame_id, source_uri.clone())
    {
        cards.push(card);
    }

    if let Some(employer) = manager_employer(text, principal)
        && let Some(card) = fact_card(
            &manager,
            "employer",
            &employer,
            frame_id,
            source_uri.clone(),
        )
    {
        cards.push(card);
    }

    if let Some(report) = reports_to(text, &manager) {
        if let Some(card) = relationship_card(
            &manager,
            "reports_to",
            &report.manager,
            frame_id,
            source_uri.clone(),
        ) {
            cards.push(card);
        }
        if let Some(title) = report.manager_title
            && let Some(card) = profile_card(
                &report.manager,
                "title",
                &title,
                frame_id,
                source_uri.clone(),
            )
        {
            cards.push(card);
        }
    }

    cards
}

fn manager_subject(text: &str, principal: &str) -> Option<String> {
    let lower = text.to_lowercase();
    let marker = format!(" is {}'s manager", principal.to_lowercase());
    let idx = lower.find(&marker)?;
    let before = text.get(..idx)?.trim();
    last_name(before)
}

fn manager_employer(text: &str, principal: &str) -> Option<String> {
    let lower = text.to_lowercase();
    let marker = format!(" is {}'s manager at ", principal.to_lowercase());
    let idx = lower.find(&marker)? + marker.len();
    let raw = text.get(idx..)?;
    clean_clause(raw, &['.', '!', '?', ';', ',', '\n'])
}

struct ReportsTo {
    manager: String,
    manager_title: Option<String>,
}

fn reports_to(text: &str, subject: &str) -> Option<ReportsTo> {
    let lower = text.to_lowercase();
    let subject_marker = format!("{} reports to ", subject.to_lowercase());
    let start = if let Some(idx) = lower.find(&subject_marker) {
        idx + subject_marker.len()
    } else if let Some(idx) = lower.find(" he reports to ") {
        idx + " he reports to ".len()
    } else if let Some(idx) = lower.find(" she reports to ") {
        idx + " she reports to ".len()
    } else {
        return None;
    };
    let raw = text.get(start..)?;
    let sentence = clean_clause(raw, &['.', '!', '?', ';', '\n'])?;
    let mut parts = sentence.splitn(2, ',');
    let manager = clean_name(parts.next()?)?;
    let manager_title = parts.next().and_then(clean_title);
    Some(ReportsTo {
        manager,
        manager_title,
    })
}

fn last_name(text: &str) -> Option<String> {
    text.split_whitespace().rev().find_map(clean_name)
}

fn clean_name(text: &str) -> Option<String> {
    let value = text
        .trim()
        .trim_matches(|c: char| !c.is_alphanumeric() && c != '_' && c != '-' && c != '\'')
        .trim();
    (!value.is_empty()).then(|| value.to_string())
}

fn clean_title(text: &str) -> Option<String> {
    let value = text
        .trim()
        .strip_prefix("the ")
        .unwrap_or_else(|| text.trim())
        .trim()
        .trim_matches(|c: char| !c.is_alphanumeric() && c != ' ' && c != '_' && c != '-')
        .trim();
    (!value.is_empty()).then(|| value.to_string())
}

fn clean_clause(text: &str, delimiters: &[char]) -> Option<String> {
    let value = text
        .split(|c| delimiters.contains(&c))
        .next()?
        .trim()
        .trim_matches(|c: char| !c.is_alphanumeric() && c != ' ' && c != '_' && c != '-')
        .trim();
    // L2: strip common corporate-entity suffixes so an extractor seeing
    // `Acme Corp.` or `Initech, LLC` materialises a card whose value is
    // just `Acme` / `Initech`, matching what downstream relationship
    // queries (and humans) actually look for. Order matters: longest
    // suffix first so `Corporation` strips before `Corp`.
    const CORP_SUFFIXES: &[&str] = &[
        " incorporated",
        " corporation",
        " company",
        " limited",
        " inc",
        " corp",
        " llc",
        " ltd",
        " co",
    ];
    let lowered = value.to_lowercase();
    let stripped = CORP_SUFFIXES
        .iter()
        .find_map(|suffix| lowered.strip_suffix(suffix).map(|head| head.len()))
        .and_then(|head_len| value.get(..head_len))
        .map(str::trim)
        .unwrap_or(value);
    (!stripped.is_empty()).then(|| stripped.to_string())
}

fn normalize_entity(entity: &str) -> String {
    entity.trim().to_lowercase()
}

fn allergy_value(text: &str) -> Option<String> {
    let lower = text.to_lowercase();
    let start = if let Some(idx) = lower.find(" allergic to ") {
        idx + " allergic to ".len()
    } else if let Some(idx) = lower.find(" allergy to ") {
        idx + " allergy to ".len()
    } else if let Some(idx) = lower.find(" cannot have ") {
        idx + " cannot have ".len()
    } else if let Some(idx) = lower.find(" can't have ") {
        idx + " can't have ".len()
    } else {
        return None;
    };
    let raw = text.get(start..)?;
    let value = raw
        .split(['.', '!', '?', ';', ',', '\n'])
        .next()?
        .trim()
        .trim_matches(|c: char| matches!(c, '.' | '!' | '?' | ';' | ',' | ':' | ' '));
    (!value.is_empty()).then(|| value.to_string())
}

/// Returns `true` if `text` contains a balanced ASCII double-quoted span
/// (`"..."`) whose contents include the standalone token `I`. Used by
/// [`bind_principal`] to refuse rewriting quoted speech.
fn quoted_span_contains_first_person(text: &str) -> bool {
    let mut in_quote = false;
    let mut span_start: usize = 0;
    for (idx, ch) in text.char_indices() {
        if ch != '"' {
            continue;
        }
        if !in_quote {
            in_quote = true;
            span_start = idx + ch.len_utf8();
        } else {
            in_quote = false;
            if let Some(span) = text.get(span_start..idx) {
                for tok in span.split_whitespace() {
                    let core = tok.trim_matches(|c: char| !c.is_alphanumeric() && c != '\'');
                    if core == "I" {
                        return true;
                    }
                }
            }
        }
    }
    false
}

fn bind_principal(text: &str, principal: &str) -> String {
    let principal = principal.trim();
    if principal.is_empty() {
        return text.to_string();
    }

    // Safety short-circuits: if the turn contains a triple-backtick code
    // fence, or a balanced double-quoted span containing the standalone
    // token `I`, refuse to rewrite. Quoted speech / code routinely
    // contains literal `I` that does not refer to the speaker.
    if text.contains("```") || quoted_span_contains_first_person(text) {
        return text.to_string();
    }

    let lower = text.to_lowercase();
    let name_prefix = format!("my name is {} and i ", principal.to_lowercase());
    if lower.starts_with(&name_prefix)
        && let Some(rest) = text.get(name_prefix.len() - "i ".len()..)
    {
        return bind_principal(rest, principal);
    }

    let mut output = Vec::new();
    let mut tokens = text.split_whitespace().peekable();
    while let Some(token) = tokens.next() {
        let core = token_core_lower(token);
        if core != "i" {
            output.push(bind_token(token, principal));
            continue;
        }

        if let Some(next) = tokens.peek() {
            let next_core = token_core_lower(next);
            if next_core == "really" {
                let really = tokens.next();
                if let (Some(really_token), Some(verb_token)) = (really, tokens.peek()) {
                    let verb_core = token_core_lower(verb_token);
                    if let Some(verb) = principal_verb(&verb_core) {
                        let suffix = token_suffix(verb_token);
                        let _ = tokens.next();
                        output.push(format!("{principal} {really_token} {verb}{suffix}"));
                        continue;
                    }
                }
                output.push(principal.to_string());
                if let Some(really_token) = really {
                    output.push(really_token.to_string());
                }
                continue;
            }
            if let Some(verb) = principal_verb(&next_core) {
                let suffix = token_suffix(next);
                let _ = tokens.next();
                output.push(format!("{principal} {verb}{suffix}"));
                continue;
            }
        }
        // Bare standalone `I` with no recognised verb follower: leave it
        // alone. This avoids misrewriting Roman numerals (`World War I`),
        // section headers, or any other context where `I` is not a
        // first-person pronoun. Recognised pronoun forms (`my`, `me`,
        // `I'm`, etc.) are handled by the `core != "i"` branch above.
        output.push(token.to_string());
    }
    output.join(" ")
}

fn token_core_lower(token: &str) -> String {
    token
        .trim_matches(|c: char| !c.is_alphanumeric() && c != '\'')
        .to_lowercase()
}

fn token_suffix(token: &str) -> String {
    token
        .chars()
        .rev()
        .take_while(|c| !c.is_alphanumeric() && *c != '\'')
        .collect::<Vec<_>>()
        .into_iter()
        .rev()
        .collect()
}

fn principal_verb(core: &str) -> Option<&'static str> {
    match core {
        "like" => Some("likes"),
        "dislike" => Some("dislikes"),
        "live" => Some("lives"),
        "work" => Some("works"),
        "grew" => Some("grew"),
        "prefer" => Some("prefers"),
        "love" => Some("loves"),
        "hate" => Some("hates"),
        "want" => Some("wants"),
        "need" => Some("needs"),
        "am" => Some("is"),
        "have" => Some("has"),
        _ => None,
    }
}

fn bind_token(token: &str, principal: &str) -> String {
    let suffix = token_suffix(token);
    let core = token_core_lower(token);
    let replacement = match core.as_str() {
        "i" => Some(principal.to_string()),
        "me" | "myself" => Some(principal.to_string()),
        "my" | "mine" => Some(format!("{principal}'s")),
        "i'm" | "im" => Some(format!("{principal} is")),
        "i've" | "ive" => Some(format!("{principal} has")),
        "i'd" | "id" => Some(format!("{principal} would")),
        "i'll" | "ill" => Some(format!("{principal} will")),
        _ => None,
    };
    match replacement {
        Some(mut value) => {
            value.push_str(&suffix);
            value
        }
        None => token.to_string(),
    }
}

/// Pull a textual representation out of a [`Message`].
///
/// `Message::rag_text` is `pub(crate)` in rig-core, so we re-implement the
/// equivalent walk here over the public content enums.
pub(crate) fn render_message_text(msg: &Message) -> Option<String> {
    use rig::completion::message::{
        AssistantContent, Message as Msg, ReasoningContent, UserContent,
    };

    match msg {
        Msg::System { content } => Some(content.clone()),
        Msg::User { content } => {
            let mut buf = String::new();
            for item in content.iter() {
                if let UserContent::Text(text) = item {
                    if !buf.is_empty() {
                        buf.push('\n');
                    }
                    buf.push_str(&text.text);
                }
            }
            (!buf.is_empty()).then_some(buf)
        }
        Msg::Assistant { content, .. } => {
            let mut buf = String::new();
            for item in content.iter() {
                match item {
                    AssistantContent::Text(text) => {
                        if !buf.is_empty() {
                            buf.push('\n');
                        }
                        buf.push_str(&text.text);
                    }
                    AssistantContent::Reasoning(reasoning) => {
                        for entry in reasoning.content.iter() {
                            if let ReasoningContent::Text { text, .. } = entry {
                                if !buf.is_empty() {
                                    buf.push('\n');
                                }
                                buf.push_str(text);
                            }
                        }
                    }
                    AssistantContent::ToolCall(_) | AssistantContent::Image(_) => {}
                }
            }
            (!buf.is_empty()).then_some(buf)
        }
    }
}

impl<M> PromptHook<M> for MemvidPersistHook<M>
where
    M: CompletionModel,
{
    async fn on_completion_call(&self, prompt: &Message, _history: &[Message]) -> HookAction {
        if let Some(text) = self.render(prompt) {
            self.write(&text, "user");
        }
        if self.should_halt() {
            return HookAction::terminate(
                "rig-memvid: persistence failed under WriteFailure::Halt",
            );
        }
        HookAction::cont()
    }

    async fn on_completion_response(
        &self,
        _prompt: &Message,
        response: &CompletionResponse<M::Response>,
    ) -> HookAction {
        if !self.config.persist_assistant {
            return HookAction::cont();
        }
        for content in response.choice.iter() {
            let synthetic = Message::Assistant {
                id: None,
                content: rig::OneOrMany::one(content.clone()),
            };
            if let Some(text) = self.render(&synthetic) {
                self.write(&text, "assistant");
            }
        }
        if self.should_halt() {
            return HookAction::terminate(
                "rig-memvid: persistence failed under WriteFailure::Halt",
            );
        }
        HookAction::cont()
    }
}

#[cfg(test)]
mod tests {
    use super::{allergy_value, bind_principal, supplemental_memory_cards};

    #[test]
    fn bind_principal_rewrites_first_person_tokens() {
        let rewritten = bind_principal(
            "My name is Alice. I'm allergic to peanuts, and I like espresso.",
            "Alice",
        );
        assert_eq!(
            rewritten,
            "Alice's name is Alice. Alice is allergic to peanuts, and Alice likes espresso."
        );
    }

    #[test]
    fn bind_principal_rewrites_common_verbs_after_adverbs() {
        assert_eq!(
            bind_principal("I really dislike instant coffee.", "Alice"),
            "Alice really dislikes instant coffee."
        );
    }

    #[test]
    fn bind_principal_collapses_name_intro_before_verbs() {
        assert_eq!(
            bind_principal(
                "My name is Alice and I work at Acme as a staff engineer.",
                "Alice",
            ),
            "Alice works at Acme as a staff engineer."
        );
    }

    #[test]
    fn bind_principal_ignores_empty_principal() {
        assert_eq!(bind_principal("I like rust", "  "), "I like rust");
    }

    #[test]
    fn bind_principal_is_idempotent() {
        let once = bind_principal("I like espresso and I dislike tea.", "Alice");
        let twice = bind_principal(&once, "Alice");
        assert_eq!(once, twice);
    }

    #[test]
    fn bind_principal_skips_quoted_speech() {
        // Quoted `I` belongs to the speaker being quoted, not the principal.
        let input = "Bob said \"I love hiking\" yesterday.";
        assert_eq!(bind_principal(input, "Alice"), input);
    }

    #[test]
    fn bind_principal_skips_code_fences() {
        // Code fences may contain literal `I` identifiers that must not be
        // rewritten.
        let input = "Try this:\n```\nlet I = 1;\n```\nthen rerun.";
        assert_eq!(bind_principal(input, "Alice"), input);
    }

    #[test]
    fn bind_principal_leaves_roman_numeral_alone() {
        // `I` here is a Roman numeral, not a pronoun; no verb in
        // `principal_verb` follows, so the rewrite must be a no-op.
        let input = "World War I ended in 1918.";
        assert_eq!(bind_principal(input, "Alice"), input);
    }

    #[test]
    fn allergy_value_extracts_common_forms() {
        assert_eq!(
            allergy_value("Alice is allergic to peanuts."),
            Some("peanuts".to_string())
        );
        assert_eq!(
            allergy_value("Alice cannot have shellfish, thanks"),
            Some("shellfish".to_string())
        );
    }

    #[test]
    fn supplemental_cards_build_allergy_profile() {
        let cards = supplemental_memory_cards(
            "Alice is allergic to peanuts.",
            "Alice",
            42,
            Some("scope".to_string()),
        );
        assert_eq!(cards.len(), 1);
        for card in &cards {
            assert_eq!(card.kind, memvid_core::MemoryKind::Profile);
            assert_eq!(card.entity, "alice");
            assert_eq!(card.slot, "allergy");
            assert_eq!(card.value, "peanuts");
            assert_eq!(card.source_frame_id, 42);
        }
    }

    #[test]
    fn supplemental_cards_build_manager_relationships() {
        let cards = supplemental_memory_cards(
            "Bob is Alice's manager at Acme. He reports to Carol, the VP.",
            "Alice",
            42,
            Some("scope".to_string()),
        );
        assert!(cards.iter().any(|card| {
            card.kind == memvid_core::MemoryKind::Relationship
                && card.entity == "alice"
                && card.slot == "manager"
                && card.value == "Bob"
        }));
        assert!(cards.iter().any(|card| {
            card.kind == memvid_core::MemoryKind::Relationship
                && card.entity == "bob"
                && card.slot == "reports_to"
                && card.value == "Carol"
        }));
        assert!(cards.iter().any(|card| {
            card.kind == memvid_core::MemoryKind::Fact
                && card.entity == "bob"
                && card.slot == "employer"
                && card.value == "Acme"
        }));
        assert!(cards.iter().any(|card| {
            card.kind == memvid_core::MemoryKind::Profile
                && card.entity == "carol"
                && card.slot == "title"
                && card.value == "VP"
        }));
    }

    #[test]
    fn builder_matches_default() {
        let from_default = super::MemoryConfig::default();
        let from_builder = super::MemoryConfig::builder().build();
        // Spot-check every field the builder is supposed to default.
        assert_eq!(from_builder.commit_each_turn, from_default.commit_each_turn);
        assert_eq!(from_builder.default_tags, from_default.default_tags);
        assert_eq!(from_builder.scope, from_default.scope);
        assert_eq!(from_builder.principal, from_default.principal);
        assert_eq!(
            from_builder.persist_assistant,
            from_default.persist_assistant
        );
        assert_eq!(
            from_builder.supplemental_profile_cards,
            from_default.supplemental_profile_cards
        );
        assert_eq!(from_builder.auto_tag, from_default.auto_tag);
        assert_eq!(from_builder.extract_dates, from_default.extract_dates);
        assert_eq!(from_builder.extract_triplets, from_default.extract_triplets);
        assert_eq!(
            from_builder.observe_conversation_id,
            from_default.observe_conversation_id
        );
        assert!(matches!(
            from_builder.on_write_failure,
            super::WriteFailure::Warn
        ));
        assert_eq!(
            from_builder.rewrite_principal_pronouns,
            from_default.rewrite_principal_pronouns
        );
        assert!(from_default.rewrite_principal_pronouns);
    }

    #[test]
    fn builder_overrides_each_field() {
        let cfg = super::MemoryConfig::builder()
            .commit_each_turn(false)
            .default_tags(vec!["t1".into()])
            .scope(Some("scope".into()))
            .principal(Some("Alice".into()))
            .persist_assistant(false)
            .supplemental_profile_cards(false)
            .auto_tag(false)
            .extract_dates(false)
            .extract_triplets(false)
            .observe_conversation_id(Some("conv-1".into()))
            .on_write_failure(super::WriteFailure::Halt)
            .rewrite_principal_pronouns(false)
            .build();
        assert!(!cfg.commit_each_turn);
        assert_eq!(cfg.default_tags, vec!["t1".to_string()]);
        assert_eq!(cfg.scope.as_deref(), Some("scope"));
        assert_eq!(cfg.principal.as_deref(), Some("Alice"));
        assert!(!cfg.persist_assistant);
        assert!(!cfg.supplemental_profile_cards);
        assert!(!cfg.auto_tag);
        assert!(!cfg.extract_dates);
        assert!(!cfg.extract_triplets);
        assert_eq!(cfg.observe_conversation_id.as_deref(), Some("conv-1"));
        assert!(matches!(cfg.on_write_failure, super::WriteFailure::Halt));
        assert!(!cfg.rewrite_principal_pronouns);
    }
}