workshop-rs 1.19.0

//! Canonical Workshop name lookup: display names, near spellings, and
//! settings paths resolve to the catalog entries, preset strings, enum
//! members, and settings definitions the parser and emitter accept.
//!
//! [`Catalog::lookup`] answers in canonical Workshop terms: which identity a
//! display name or guess refers to, which parameters and argument domains an
//! action or value declares, which members an enum domain accepts, and which
//! settings keys, kinds, and value forms a path or display name selects.
//! Every answer derives from the same catalog and settings table that drive
//! parsing and emission, so lookup results cannot drift from the accepted
//! vocabulary. Consumers compose and present the matches; this module owns
//! no data of its own.

use crate::catalog::{Catalog, CatalogEntry, EnumDomain, Kind, Locale};
use crate::core::error::{Result, WorkshopError};
use crate::core::suggest;
use crate::settings::{self, PathPart, SettingDefinition, SettingValueDomain, table};

const INLINE_MEMBER_LIMIT: usize = 32;

/// One canonical construct matching a [`Catalog::lookup`] query.
#[derive(Debug, Clone, PartialEq)]
#[non_exhaustive]
pub enum LookupMatch {
    /// A catalog builtin: structural keyword, action, value, event, or
    /// operator.
    Builtin {
        /// The entry's catalog kind.
        kind: Kind,
        /// The canonical identity (`createHudText`, `global`).
        id: String,
        /// The display name in the requested locale, when mapped.
        display_name: Option<String>,
        /// The call signature, for actions and values.
        signature: Option<Signature>,
    },
    /// A member of a canonical enum domain (`Team.ALL`, `Hero.SOLDIER_76`).
    EnumMember {
        /// The canonical domain name.
        domain: String,
        /// The canonical member id.
        member: String,
        /// The member's display name in the requested locale, when mapped.
        display_name: Option<String>,
    },
    /// A canonical enum domain and the members it accepts.
    EnumDomain {
        /// The canonical domain name.
        domain: String,
        /// The domain's display name in the requested locale, when mapped.
        display_name: Option<String>,
        /// Every member the domain accepts.
        members: Vec<LookupEnumMember>,
    },
    /// A reviewed settings-table definition: a valid key with its path,
    /// kind, and value forms.
    Setting {
        /// The canonical semantic definition.
        definition: SettingDefinition,
        /// The display name in the requested locale, or the English name
        /// when the locale has no mapping.
        display_name: String,
    },
    /// A parameter of a scoped callable, in call order. Returned only by
    /// [`Catalog::lookup_within`]; an unscoped [`Catalog::lookup`] never
    /// answers parameters.
    Parameter {
        /// The callable's canonical id.
        callable: String,
        /// The parameter's position in call order.
        position: usize,
        /// Whether the position must be supplied.
        required: bool,
        /// The parameter facts: name, declared type, domain, and default.
        param: SignatureParam,
        /// The enum domain this parameter accepts, with the members it
        /// accepts, when the parameter is enum-typed.
        domain: Option<SignatureDomain>,
    },
    /// The next path segment below a scoped settings prefix — an
    /// intermediate selector such as `<team>` or `general`, not a leaf
    /// key. Returned only by [`Catalog::lookup_within`].
    SettingPath {
        /// The full child path under the scoped prefix (`heroes.<team>`).
        path: String,
        /// The segment text (`<team>`, `general`).
        segment: String,
    },
    /// A preset localized string identity from the catalog's
    /// `localizedStrings` table — the id a `{"localizedString": id}`
    /// rule-content node or a `Value::LocalizedString` carries.
    LocalizedString {
        /// The canonical id (`hello`, `goodbye`).
        id: String,
        /// The display name in the requested locale, when mapped — the
        /// spelling the emitter writes for that locale.
        display_name: Option<String>,
    },
}

/// A canonical enum member reported by a lookup.
#[derive(Debug, Clone, PartialEq)]
#[non_exhaustive]
pub struct LookupEnumMember {
    /// The canonical member id (`SOLDIER_76`, `ALL`).
    pub id: String,
    /// The member's display name in the requested locale, when mapped.
    pub display_name: Option<String>,
}

/// An enum domain referenced by a [`Signature`] parameter, with the members
/// it accepts.
#[derive(Debug, Clone, PartialEq)]
#[non_exhaustive]
pub struct SignatureDomain {
    /// The canonical domain name.
    pub domain: String,
    /// Every member the domain accepts.
    pub members: Vec<LookupEnumMember>,
}

/// A compact signature for a catalog action or value.
#[derive(Debug, Clone, PartialEq)]
#[non_exhaustive]
pub struct Signature {
    /// The signature rendered in the requested locale's call syntax:
    /// parameters appear in call order, a parameter without a declared
    /// default reads `name: Type`, a parameter with a declared default reads
    /// `name=default` or `name?` when the default is null, and an enum-typed
    /// parameter without a default reads `name: Domain(members)` listing the
    /// domain's members once per signature when it has at most
    /// 32 members, or `name: Domain(count members)` for a larger domain.
    pub text: String,
    /// Parameters in call order.
    pub params: Vec<SignatureParam>,
    /// The argument count a call must supply: positions below this index
    /// cannot be omitted; declared defaults only make the suffix optional.
    pub required_params: usize,
    /// Whether the final parameter repeats for extra arguments.
    pub variadic: bool,
    /// The source-backed return type for values, when declared.
    pub return_type: Option<String>,
    /// The enum domains referenced by parameters, each with the members it
    /// accepts, for follow-up inspection of large domains.
    pub domains: Vec<SignatureDomain>,
}

/// One parameter of a [`Signature`].
#[derive(Debug, Clone, PartialEq)]
#[non_exhaustive]
pub struct SignatureParam {
    /// The semantic parameter name, or the catalog parameter name.
    pub name: String,
    /// The source-backed semantic type, when declared.
    pub param_type: Option<String>,
    /// The canonical enum domain expected at this position, when declared.
    pub domain: Option<String>,
    /// The declared default applied when the argument is omitted. `None`
    /// marks a parameter with no declared default; a declared default before
    /// another required position does not make this position omittable (see
    /// [`Signature::required_params`]).
    pub default: Option<String>,
}

impl Catalog {
    /// Find canonical constructs matching `query` under `locale`.
    ///
    /// `query` may be a display name in `locale`, a primary-locale display
    /// name, a canonical id, a near spelling or guess, or a settings path
    /// prefix (`gamemodes.control`, `heroes.<team>.<hero>`). Matches rank
    /// exact spellings first, then near spellings, token prefixes, and
    /// substring guesses; ties keep catalog and table order. All matches are
    /// canonical constructs the parser and emitter accept, with the display
    /// name in `locale` and, for actions and values, the compact signature.
    ///
    /// An empty result reports that nothing matched. `Err` reports a query
    /// the catalog cannot answer: a locale the catalog does not declare.
    ///
    /// ```
    /// use workshop_rs::catalog::{Catalog, Locale};
    /// use workshop_rs::lookup::LookupMatch;
    ///
    /// let catalog = Catalog::builtin().unwrap();
    /// let matches = catalog.lookup(&Locale::new("en-US"), "create hud txt").unwrap();
    /// assert!(matches.iter().any(|m| matches!(
    ///     m,
    ///     LookupMatch::Builtin { id, .. } if id == "createHudText"
    /// )));
    /// ```
    pub fn lookup(&self, locale: &Locale, query: &str) -> Result<Vec<LookupMatch>> {
        self.check_locale(locale)?;
        let primary = self.primary_locale();
        let distinct_locale = locale != primary;
        let prepared = PreparedQuery::new(query);
        let query_segments: Vec<&str> = query.split('.').collect();
        let mut matches: Vec<(u32, LookupMatch)> = Vec::new();
        for entry in &self.entries {
            let primary_spellings: &[String] = if distinct_locale {
                entry.spellings(primary)
            } else {
                &[]
            };
            let score = std::iter::once(entry.id.as_str())
                .chain(entry.spellings(locale).iter().map(String::as_str))
                .chain(primary_spellings.iter().map(String::as_str))
                .filter_map(|text| prepared.name_score(text))
                .min();
            if let Some(score) = score {
                matches.push((score, self.builtin_match(entry, locale)));
            }
        }
        for entry in &self.localized_strings {
            let primary_spellings: &[String] = if distinct_locale {
                entry.spellings(primary)
            } else {
                &[]
            };
            let score = std::iter::once(entry.id.as_str())
                .chain(entry.spellings(locale).iter().map(String::as_str))
                .chain(primary_spellings.iter().map(String::as_str))
                .filter_map(|text| prepared.name_score(text))
                .min();
            if let Some(score) = score {
                matches.push((
                    score,
                    LookupMatch::LocalizedString {
                        id: entry.id.clone(),
                        display_name: entry.spelling(locale).map(String::from),
                    },
                ));
            }
        }
        for domain in self.enum_domains() {
            let score = std::iter::once(domain.domain.as_str())
                .chain(domain.spelling(locale))
                .chain(domain.spelling(primary).filter(|_| distinct_locale))
                .filter_map(|text| prepared.name_score(text))
                .min();
            if let Some(score) = score {
                matches.push((score, self.enum_domain_match(domain, locale)));
            }
        }
        for domain in self.enum_domains() {
            for member in &domain.members {
                let qualified = format!("{}.{}", domain.domain, member.member);
                let primary_spellings: &[String] = if distinct_locale {
                    member.spellings(primary)
                } else {
                    &[]
                };
                let score = std::iter::once(member.member.as_str())
                    .chain(std::iter::once(qualified.as_str()))
                    .chain(member.spellings(locale).iter().map(String::as_str))
                    .chain(primary_spellings.iter().map(String::as_str))
                    .filter_map(|text| prepared.name_score(text))
                    .min();
                if let Some(score) = score {
                    matches.push((
                        score,
                        LookupMatch::EnumMember {
                            domain: domain.domain.clone(),
                            member: member.member.clone(),
                            display_name: self
                                .enum_spelling(&domain.domain, locale, &member.member)
                                .map(String::from),
                        },
                    ));
                }
            }
        }
        for definition in settings::definitions() {
            let name_texts = [
                Some(definition.path().rsplit('.').next().unwrap_or_default()),
                Some(definition.presentation().english_name),
                definition.presentation().localized_name(locale.as_str()),
                definition.id().map(|id| id.as_str()),
                Some(definition.path()),
            ];
            let score = name_texts
                .into_iter()
                .flatten()
                .filter_map(|text| prepared.name_score(text))
                .min()
                .into_iter()
                .chain(path_prefix_score(&query_segments, definition.path()))
                .min();
            if let Some(score) = score {
                matches.push((
                    score,
                    LookupMatch::Setting {
                        display_name: definition
                            .presentation()
                            .localized_name(locale.as_str())
                            .unwrap_or(definition.presentation().english_name)
                            .to_string(),
                        definition,
                    },
                ));
            }
        }
        matches.sort_by_key(|(score, _)| *score);
        Ok(matches.into_iter().map(|(_, lookup)| lookup).collect())
    }

    /// The entries `within` contains under `locale` — the members of an
    /// enum domain, the parameters of a callable, or the settings keys
    /// and segments under a path prefix — optionally filtered and ranked
    /// by `query` with the same matcher an unscoped [`Catalog::lookup`]
    /// uses.
    ///
    /// `within` resolves in a fixed order: an enum domain (catalog or
    /// settings-table), an action or value id or `locale` spelling, then
    /// a settings path prefix. Template segments (`<team>`, `<hero>`)
    /// accept their own template spelling or a canonical team/hero key
    /// the settings table recognizes — never an arbitrary value — so a
    /// literal path stays literal (`heroes.general` lists only the
    /// `general` group's children). With no `query`, or an
    /// empty one, children keep the scope's own order — domain order for
    /// members, call order for parameters, table order for settings — and
    /// a non-empty query filters and ranks them by the same scoring an
    /// unscoped lookup applies to its candidates.
    ///
    /// `Err` reports a locale the catalog does not declare or a `within`
    /// naming no known scope; an empty result reports a scope whose
    /// children do not match `query`.
    ///
    /// ```
    /// use workshop_rs::catalog::{Catalog, Locale};
    /// use workshop_rs::lookup::LookupMatch;
    ///
    /// let catalog = Catalog::builtin().unwrap();
    /// let members = catalog
    ///     .lookup_within(&Locale::new("en-US"), "Team", None)
    ///     .unwrap();
    /// assert!(members.iter().all(|m| matches!(m, LookupMatch::EnumMember { domain, .. } if domain == "Team")));
    /// ```
    pub fn lookup_within(
        &self,
        locale: &Locale,
        within: &str,
        query: Option<&str>,
    ) -> Result<Vec<LookupMatch>> {
        self.check_locale(locale)?;
        let prepared = query
            .filter(|query| !query.is_empty())
            .map(PreparedQuery::new);
        let mut scored = self
            .within_enum_domain(locale, within, prepared.as_ref())
            .or_else(|| self.within_settings_enum(locale, within, prepared.as_ref()))
            .or_else(|| self.within_callable(locale, within, prepared.as_ref()))
            .or_else(|| within_settings(within, locale, prepared.as_ref()))
            .ok_or_else(|| WorkshopError::unknown("lookup scope", within, locale.clone(), None))?;
        if prepared.is_some() {
            scored.retain(|(score, _)| *score != u32::MAX);
            scored.sort_by_key(|(score, _)| *score);
        }
        Ok(scored.into_iter().map(|(_, lookup)| lookup).collect())
    }

    /// Every entry of a listable `kind` under `locale` — one
    /// [`LookupMatch`] per catalog entry of the kind, in catalog order,
    /// with no query, matching, or ranking.
    ///
    /// `Kind::Action`, `Kind::Value`, and `Kind::Event` list one
    /// [`LookupMatch::Builtin`] per entry — the same match
    /// [`Catalog::lookup`] builds for that entry, signature included.
    /// `Kind::Enum` lists one [`LookupMatch::EnumDomain`] per declared
    /// enum domain, in [`Catalog::enum_domains`] order. Enum members and
    /// call parameters are scoped children that already list through
    /// [`Catalog::lookup_within`]; the other kinds have no listing
    /// surface, and naming one is an `Err`.
    ///
    /// `Err` reports a locale the catalog does not declare or a `kind`
    /// with no listing surface. The result is the complete listable
    /// vocabulary of the kind: paging and presentation belong to the
    /// consumer.
    ///
    /// ```
    /// use workshop_rs::catalog::{Catalog, Kind, Locale};
    /// use workshop_rs::lookup::LookupMatch;
    ///
    /// let catalog = Catalog::builtin().unwrap();
    /// let events = catalog
    ///     .lookup_entries(&Locale::new("en-US"), Kind::Event)
    ///     .unwrap();
    /// assert!(events.iter().all(
    ///     |m| matches!(m, LookupMatch::Builtin { kind: Kind::Event, .. })
    /// ));
    /// ```
    pub fn lookup_entries(&self, locale: &Locale, kind: Kind) -> Result<Vec<LookupMatch>> {
        self.check_locale(locale)?;
        match kind {
            Kind::Action | Kind::Value | Kind::Event => Ok(self
                .entries_of(kind)
                .map(|entry| self.builtin_match(entry, locale))
                .collect()),
            Kind::Enum => Ok(self
                .enum_domains()
                .map(|domain| self.enum_domain_match(domain, locale))
                .collect()),
            Kind::Structural | Kind::Operator | Kind::Setting => Err(WorkshopError::unsupported(
                format!(
                    "listing kind '{}' is not supported: \
                     the listable kinds are action, value, event, and enum",
                    kind.as_str()
                ),
                None,
            )),
        }
    }

    fn check_locale(&self, locale: &Locale) -> Result<()> {
        if self.supports(locale) {
            return Ok(());
        }
        Err(WorkshopError::unsupported(
            format!(
                "lookup for locale '{locale}' is not supported: \
                 the catalog does not declare it"
            ),
            None,
        ))
    }

    fn builtin_match(&self, entry: &CatalogEntry, locale: &Locale) -> LookupMatch {
        LookupMatch::Builtin {
            kind: entry.kind,
            id: entry.id.clone(),
            display_name: entry.spelling(locale).map(String::from),
            signature: signature(self, entry, locale),
        }
    }

    fn enum_domain_match(&self, domain: &EnumDomain, locale: &Locale) -> LookupMatch {
        LookupMatch::EnumDomain {
            domain: domain.domain.clone(),
            display_name: domain.spelling(locale).map(String::from),
            members: self.enum_members(&domain.domain, locale),
        }
    }

    fn within_enum_domain(
        &self,
        locale: &Locale,
        value: &str,
        prepared: Option<&PreparedQuery>,
    ) -> Option<Vec<(u32, LookupMatch)>> {
        let domain = if self.enum_domain(value).is_some() {
            Some(value.to_string())
        } else {
            self.resolve_enum_domain(locale, value).map(str::to_string)
        }?;
        let domain = self.enum_domain(&domain)?;
        let primary = self.primary_locale();
        let distinct_locale = locale != primary;
        Some(
            domain
                .members
                .iter()
                .map(|member| {
                    let qualified = format!("{}.{}", domain.domain, member.member);
                    let mut texts = vec![member.member.as_str(), qualified.as_str()];
                    texts.extend(member.spellings(locale).iter().map(String::as_str));
                    if distinct_locale {
                        texts.extend(member.spellings(primary).iter().map(String::as_str));
                    }
                    (
                        child_score(prepared, texts.into_iter()),
                        LookupMatch::EnumMember {
                            domain: domain.domain.clone(),
                            member: member.member.clone(),
                            display_name: self
                                .enum_spelling(&domain.domain, locale, &member.member)
                                .map(String::from),
                        },
                    )
                })
                .collect(),
        )
    }

    fn within_settings_enum(
        &self,
        locale: &Locale,
        value: &str,
        prepared: Option<&PreparedQuery>,
    ) -> Option<Vec<(u32, LookupMatch)>> {
        let mut seen = std::collections::HashSet::new();
        let mut members = Vec::new();
        for definition in settings::definitions() {
            let SettingValueDomain::Enum { domain } = definition.domain() else {
                continue;
            };
            if domain.as_str() != value {
                continue;
            }
            for member in definition.enum_members() {
                if !seen.insert((member.domain().to_string(), member.id().to_string())) {
                    continue;
                }
                let localized =
                    table::localized_name(locale.as_str(), "enums", member.english_name());
                let qualified = format!("{}.{}", member.domain(), member.id());
                members.push((
                    child_score(
                        prepared,
                        [
                            member.id(),
                            qualified.as_str(),
                            member.english_name(),
                            localized.unwrap_or_default(),
                        ]
                        .into_iter(),
                    ),
                    LookupMatch::EnumMember {
                        domain: member.domain().to_string(),
                        member: member.id().to_string(),
                        display_name: Some(localized.unwrap_or(member.english_name()).to_string()),
                    },
                ));
            }
        }
        (!members.is_empty()).then_some(members)
    }

    fn within_callable(
        &self,
        locale: &Locale,
        value: &str,
        prepared: Option<&PreparedQuery>,
    ) -> Option<Vec<(u32, LookupMatch)>> {
        let entry = [Kind::Action, Kind::Value].into_iter().find_map(|kind| {
            self.entry(kind, value)
                .or_else(|| self.resolve(kind, locale, value))
        })?;
        let signature = signature(self, entry, locale)?;
        Some(
            signature
                .params
                .iter()
                .enumerate()
                .map(|(position, param)| {
                    let qualified = format!("{}.{}", entry.id, param.name);
                    (
                        child_score(
                            prepared,
                            [param.name.as_str(), qualified.as_str()].into_iter(),
                        ),
                        LookupMatch::Parameter {
                            callable: entry.id.clone(),
                            position,
                            required: position < signature.required_params,
                            param: param.clone(),
                            domain: param.domain.as_ref().and_then(|name| {
                                signature
                                    .domains
                                    .iter()
                                    .find(|domain| &domain.domain == name)
                                    .cloned()
                            }),
                        },
                    )
                })
                .collect(),
        )
    }

    fn enum_members(&self, domain: &str, locale: &Locale) -> Vec<LookupEnumMember> {
        self.enum_domain(domain)
            .map(|domain| {
                domain
                    .members
                    .iter()
                    .map(|member| LookupEnumMember {
                        id: member.member.clone(),
                        display_name: self
                            .enum_spelling(&domain.domain, locale, &member.member)
                            .map(String::from),
                    })
                    .collect()
            })
            .unwrap_or_default()
    }
}

fn signature(catalog: &Catalog, entry: &CatalogEntry, locale: &Locale) -> Option<Signature> {
    if !matches!(entry.kind, Kind::Action | Kind::Value) {
        return None;
    }
    let params: Vec<SignatureParam> = (0..entry.param_count())
        .map(|index| SignatureParam {
            name: entry.param_name(index).unwrap_or_default().to_string(),
            param_type: entry.param_type(index).map(String::from),
            domain: entry.param_domain(index).map(String::from),
            default: entry.param_default(index).map(String::from),
        })
        .collect();
    let mut domains = Vec::new();
    for param in &params {
        let Some(domain) = &param.domain else {
            continue;
        };
        if domains
            .iter()
            .any(|known: &SignatureDomain| known.domain == *domain)
        {
            continue;
        }
        domains.push(SignatureDomain {
            domain: domain.clone(),
            members: catalog.enum_members(domain, locale),
        });
    }
    Some(Signature {
        text: signature_text(catalog, entry, locale, &params),
        params,
        required_params: entry.required_param_count(),
        variadic: entry.is_variadic(),
        return_type: entry.return_type().map(String::from),
        domains,
    })
}

fn signature_text(
    catalog: &Catalog,
    entry: &CatalogEntry,
    locale: &Locale,
    params: &[SignatureParam],
) -> String {
    let display = entry.spelling(locale).unwrap_or(entry.id.as_str());
    let mut listed_domains = std::collections::HashSet::new();
    let mut rendered: Vec<String> = Vec::with_capacity(params.len());
    for param in params {
        rendered.push(match &param.default {
            Some(default) if default == "null" => format!("{}?", param.name),
            Some(default) => format!(
                "{}={}",
                param.name,
                render_default(catalog, locale, default)
            ),
            None => match &param.domain {
                Some(domain) => {
                    let Some(domain_entry) = catalog.enum_domain(domain) else {
                        match &param.param_type {
                            Some(param_type) => {
                                rendered.push(format!("{}: {}", param.name, param_type));
                            }
                            None => rendered.push(param.name.clone()),
                        }
                        continue;
                    };
                    let domain_display = domain_entry
                        .spelling(locale)
                        .unwrap_or(domain_entry.domain.as_str());
                    if !listed_domains.insert(domain.clone()) {
                        format!("{}: {}", param.name, domain_display)
                    } else if domain_entry.members.len() <= INLINE_MEMBER_LIMIT {
                        let members = domain_entry
                            .members
                            .iter()
                            .map(|member| {
                                catalog
                                    .enum_spelling(&domain_entry.domain, locale, &member.member)
                                    .unwrap_or(member.member.as_str())
                            })
                            .collect::<Vec<_>>()
                            .join("|");
                        format!("{}: {}({})", param.name, domain_display, members)
                    } else {
                        format!(
                            "{}: {}({} members)",
                            param.name,
                            domain_display,
                            domain_entry.members.len()
                        )
                    }
                }
                None => match &param.param_type {
                    Some(param_type) => format!("{}: {}", param.name, param_type),
                    None => param.name.clone(),
                },
            },
        });
    }
    if entry.is_variadic() {
        rendered.push("...".to_string());
    }
    format!("{}({})", display, rendered.join(", "))
}

fn render_default(catalog: &Catalog, locale: &Locale, default: &str) -> String {
    if let Some((domain, member)) = default.split_once('.') {
        if let Some(member_spelling) = catalog.enum_spelling(domain, locale, member) {
            return catalog.enum_member_form(domain, member_spelling, locale);
        }
    }
    catalog
        .spelling(Kind::Value, locale, default)
        .unwrap_or(default)
        .to_string()
}

fn child_score<'a>(prepared: Option<&PreparedQuery>, texts: impl Iterator<Item = &'a str>) -> u32 {
    prepared
        .and_then(|prepared| texts.filter_map(|text| prepared.name_score(text)).min())
        .unwrap_or(u32::MAX)
}

fn declared_segment_accepts(declared: PathPart<'_>, asked: &str) -> bool {
    match declared {
        PathPart::Part(name) => name == asked,
        PathPart::Team => asked == "<team>" || table::team_name(asked).is_some(),
        PathPart::Hero => asked == "<hero>" || table::hero_name(asked).is_some(),
    }
}

fn within_settings(
    prefix: &str,
    locale: &Locale,
    prepared: Option<&PreparedQuery>,
) -> Option<Vec<(u32, LookupMatch)>> {
    let prefix_segments: Vec<&str> = if prefix.is_empty() {
        Vec::new()
    } else {
        prefix.split('.').collect()
    };
    let mut seen = std::collections::HashSet::new();
    let mut children = Vec::new();
    let mut known = prefix.is_empty();
    for definition in settings::definitions() {
        let parts = definition.path_parts();
        if parts.len() < prefix_segments.len() {
            continue;
        }
        let matches_prefix = prefix_segments
            .iter()
            .zip(parts.iter())
            .all(|(asked, declared)| declared_segment_accepts(*declared, asked));
        if !matches_prefix {
            continue;
        }
        known = true;
        if parts.len() == prefix_segments.len() {
            continue;
        }
        let segment = match &parts[prefix_segments.len()] {
            PathPart::Part(name) => *name,
            PathPart::Team => "<team>",
            PathPart::Hero => "<hero>",
        };
        let child_path = if prefix.is_empty() {
            segment.to_string()
        } else {
            format!("{prefix}.{segment}")
        };
        if parts.len() == prefix_segments.len() + 1 {
            if !seen.insert(definition.path().to_string()) {
                continue;
            }
            let texts = [
                Some(definition.path().rsplit('.').next().unwrap_or_default()),
                Some(definition.presentation().english_name),
                definition.presentation().localized_name(locale.as_str()),
                definition.id().map(|id| id.as_str()),
                Some(definition.path()),
            ];
            children.push((
                child_score(prepared, texts.into_iter().flatten()),
                LookupMatch::Setting {
                    display_name: definition
                        .presentation()
                        .localized_name(locale.as_str())
                        .unwrap_or(definition.presentation().english_name)
                        .to_string(),
                    definition,
                },
            ));
        } else if seen.insert(child_path.clone()) {
            children.push((
                child_score(prepared, [segment, child_path.as_str()].into_iter()),
                LookupMatch::SettingPath {
                    path: child_path,
                    segment: segment.to_string(),
                },
            ));
        }
    }
    known.then_some(children)
}

struct PreparedQuery {
    raw: String,
    folded: String,
    folded_chars: Vec<char>,
    tokens: Vec<String>,
    max_distance: usize,
    /// The folded length at which token-prefix and substring matching
    /// start. A script without word spacing carries a whole word in two
    /// characters (`阈值`, `スロットル`), so its queries match loosely at
    /// two; word-spaced queries keep three, so a two-letter ASCII query
    /// does not flood the results.
    loose_min_chars: usize,
}

impl PreparedQuery {
    fn new(query: &str) -> Self {
        let folded = suggest::fold_loose(query);
        let folded_chars: Vec<char> = folded.chars().collect();
        let loose_min_chars = if folded_chars
            .iter()
            .any(|&character| is_unspaced_script(character))
        {
            2
        } else {
            3
        };
        Self {
            raw: query.to_string(),
            max_distance: suggest::max_distance(folded_chars.len()),
            folded,
            folded_chars,
            tokens: query
                .split(|character: char| !character.is_alphanumeric())
                .map(suggest::fold_loose)
                .filter(|token| !token.is_empty())
                .collect(),
            loose_min_chars,
        }
    }

    fn name_score(&self, candidate: &str) -> Option<u32> {
        if self.raw == candidate {
            return Some(0);
        }
        let candidate_folded = fold_candidate(candidate);
        if self.folded.is_empty() || candidate_folded.is_empty() {
            return None;
        }
        if self.folded == candidate_folded {
            return Some(1);
        }
        if candidate_folded
            .chars()
            .count()
            .abs_diff(self.folded_chars.len())
            <= self.max_distance
        {
            let candidate_chars: Vec<char> = candidate_folded.chars().collect();
            let distance =
                suggest::edit_distance(&self.folded_chars, &candidate_chars, self.max_distance);
            if distance <= self.max_distance {
                return Some(2 + distance as u32);
            }
        }
        if self.folded_chars.len() >= self.loose_min_chars {
            if self.token_prefix_match(candidate) {
                return Some(6);
            }
            if candidate_folded.contains(&self.folded) {
                return Some(8);
            }
        }
        None
    }

    fn token_prefix_match(&self, candidate: &str) -> bool {
        let candidate_tokens = candidate
            .split(|character: char| !character.is_alphanumeric())
            .map(fold_candidate)
            .filter(|token| !token.is_empty());
        !self.tokens.is_empty()
            && self.tokens.iter().all(|token| {
                candidate_tokens
                    .clone()
                    .any(|candidate| candidate.starts_with(token))
            })
    }
}

/// Whether `character` belongs to a CJK script written without word
/// spacing — unified ideographs, kana, or hangul — where two characters
/// already carry a complete word.
fn is_unspaced_script(character: char) -> bool {
    matches!(
        character,
        '\u{1100}'..='\u{11FF}'   // Hangul Jamo
            | '\u{3040}'..='\u{309F}' // Hiragana
            | '\u{30A0}'..='\u{30FF}' // Katakana
            | '\u{3400}'..='\u{4DBF}' // CJK Unified Ideographs Extension A
            | '\u{4E00}'..='\u{9FFF}' // CJK Unified Ideographs
            | '\u{AC00}'..='\u{D7AF}' // Hangul Syllables
            | '\u{F900}'..='\u{FAFF}' // CJK Compatibility Ideographs
            | '\u{FF66}'..='\u{FF9D}' // Halfwidth katakana
    )
}

fn fold_candidate(candidate: &str) -> String {
    if candidate.is_ascii() {
        candidate
            .bytes()
            .filter(u8::is_ascii_alphanumeric)
            .map(|byte| char::from(byte.to_ascii_lowercase()))
            .collect()
    } else {
        suggest::fold_loose(candidate)
    }
}

fn path_prefix_score(query_segments: &[&str], path: &str) -> Option<u32> {
    let mut path_segments = path.split('.');
    let mut consumed = 0usize;
    for segment in query_segments {
        match path_segments.next() {
            Some("<team>") | Some("<hero>") => {}
            Some(part) if part.eq_ignore_ascii_case(segment) => {}
            _ => return None,
        }
        consumed += 1;
    }
    let depth = path.matches('.').count() + 1;
    Some(2 + (depth - consumed) as u32)
}