SPlit up

server-rs/src/data/property/address_search.rs

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+//! Address search: tokenization, query parsing, inverted/prefix indexes and the
+//! ranked per-row search over property addresses.
+
+use rustc_hash::{FxHashMap, FxHashSet};
+
+use super::PropertyData;
+
+/// Upper bound on rows scored per query. Intersection keeps most candidate sets far below
+/// this; only a single very common road word (e.g. "high") approaches it, and the in-area
+/// priority sort keeps a refined query's matches ahead of the cut.
+const ADDRESS_SEARCH_CANDIDATE_LIMIT: usize = 150_000;
+const ADDRESS_SEARCH_PREFIX_MIN_LEN: usize = 4;
+const ADDRESS_SEARCH_PREFIX_MAX_LEN: usize = 8;
+
+#[derive(Clone, Debug)]
+pub(super) struct AddressTermGroup {
+    alternatives: Vec<String>,
+}
+
+#[derive(Debug)]
+pub(super) struct AddressQuery {
+    full_postcode: Option<String>,
+    /// Compact uppercase outward code (optionally with a sector digit) recovered when the
+    /// user appended a partial postcode like "NW1" or "NW1 6". Used as an additive ranking
+    /// bias, never as a hard filter — so the disambiguating hint is honoured without
+    /// excluding the same road in other areas.
+    postcode_area: Option<String>,
+    text_groups: Vec<AddressTermGroup>,
+    numeric_terms: Vec<String>,
+    candidate_terms: Vec<String>,
+}
+
+fn tokenize_address_text(text: &str) -> Vec<String> {
+    let mut tokens = Vec::new();
+    let mut current = String::new();
+
+    for ch in text.chars() {
+        if ch.is_ascii_alphanumeric() {
+            current.push(ch.to_ascii_lowercase());
+        } else if matches!(ch, '\'' | '’' | '`') {
+            continue;
+        } else if !current.is_empty() {
+            tokens.push(std::mem::take(&mut current));
+        }
+    }
+
+    if !current.is_empty() {
+        tokens.push(current);
+    }
+
+    tokens
+}
+
+fn is_full_postcode_compact(compact: &str) -> bool {
+    let bytes = compact.as_bytes();
+    let len = bytes.len();
+    if !(5..=7).contains(&len) {
+        return false;
+    }
+
+    let inward = &bytes[len - 3..];
+    if !inward[0].is_ascii_digit()
+        || !inward[1].is_ascii_alphabetic()
+        || !inward[2].is_ascii_alphabetic()
+    {
+        return false;
+    }
+
+    let outward = &bytes[..len - 3];
+    if !(2..=4).contains(&outward.len()) {
+        return false;
+    }
+
+    outward[0].is_ascii_alphabetic()
+        && outward.iter().all(u8::is_ascii_alphanumeric)
+        && outward.iter().any(u8::is_ascii_digit)
+}
+
+fn canonical_postcode_from_compact(compact: &str) -> String {
+    let upper = compact.to_ascii_uppercase();
+    let split = upper.len() - 3;
+    format!("{} {}", &upper[..split], &upper[split..])
+}
+
+fn extract_full_postcode(tokens: &[String]) -> Option<(String, Vec<usize>)> {
+    for (idx, token) in tokens.iter().enumerate() {
+        let compact = token.to_ascii_uppercase();
+        if is_full_postcode_compact(&compact) {
+            return Some((canonical_postcode_from_compact(&compact), vec![idx]));
+        }
+    }
+
+    for idx in 0..tokens.len().saturating_sub(1) {
+        let compact = format!(
+            "{}{}",
+            tokens[idx].to_ascii_uppercase(),
+            tokens[idx + 1].to_ascii_uppercase()
+        );
+        if is_full_postcode_compact(&compact) {
+            return Some((
+                canonical_postcode_from_compact(&compact),
+                vec![idx, idx + 1],
+            ));
+        }
+    }
+
+    None
+}
+
+fn looks_like_postcode_fragment(token: &str) -> bool {
+    (2..=4).contains(&token.len())
+        && token
+            .chars()
+            .next()
+            .is_some_and(|ch| ch.is_ascii_alphabetic())
+        && token.chars().any(|ch| ch.is_ascii_digit())
+        && token.chars().all(|ch| ch.is_ascii_alphanumeric())
+}
+
+fn is_numeric_address_token(token: &str) -> bool {
+    token.chars().all(|ch| ch.is_ascii_digit())
+}
+
+fn address_token_aliases(token: &str) -> Vec<&'static str> {
+    match token {
+        "apt" => vec!["apt", "apartment"],
+        "apartment" => vec!["apartment", "apt"],
+        "ave" => vec!["ave", "avenue"],
+        "avenue" => vec!["avenue", "ave"],
+        "blvd" => vec!["blvd", "boulevard"],
+        "boulevard" => vec!["boulevard", "blvd"],
+        "cl" => vec!["cl", "close"],
+        "close" => vec!["close", "cl"],
+        "ct" => vec!["ct", "court"],
+        "court" => vec!["court", "ct"],
+        "cres" => vec!["cres", "crescent"],
+        "crescent" => vec!["crescent", "cres"],
+        "dr" => vec!["dr", "drive"],
+        "drive" => vec!["drive", "dr"],
+        "fl" => vec!["fl", "flat"],
+        "flat" => vec!["flat", "fl"],
+        "gdns" => vec!["gdns", "gardens", "garden"],
+        "garden" => vec!["garden", "gardens", "gdns"],
+        "gardens" => vec!["gardens", "garden", "gdns"],
+        "hse" => vec!["hse", "house"],
+        "house" => vec!["house", "hse"],
+        "ln" => vec!["ln", "lane"],
+        "lane" => vec!["lane", "ln"],
+        "rd" => vec!["rd", "road"],
+        "road" => vec!["road", "rd"],
+        "sq" => vec!["sq", "square"],
+        "square" => vec!["square", "sq"],
+        "st" => vec!["st", "street", "saint"],
+        "street" => vec!["street", "st"],
+        "saint" => vec!["saint", "st"],
+        "terr" => vec!["terr", "terrace"],
+        "terrace" => vec!["terrace", "terr"],
+        _ => Vec::new(),
+    }
+}
+
+fn is_address_stop_token(token: &str) -> bool {
+    matches!(
+        token,
+        "a" | "an"
+            | "and"
+            | "apartment"
+            | "apt"
+            | "avenue"
+            | "ave"
+            | "block"
+            | "building"
+            | "bungalow"
+            | "close"
+            | "cl"
+            | "court"
+            | "ct"
+            | "cres"
+            | "crescent"
+            | "drive"
+            | "dr"
+            | "estate"
+            | "flat"
+            | "fl"
+            | "floor"
+            | "garden"
+            | "gardens"
+            | "gdns"
+            | "grove"
+            | "house"
+            | "hse"
+            | "lane"
+            | "ln"
+            | "lodge"
+            | "mansions"
+            | "mews"
+            | "of"
+            | "park"
+            | "place"
+            | "road"
+            | "rd"
+            | "room"
+            | "row"
+            | "saint"
+            | "sq"
+            | "square"
+            | "st"
+            | "street"
+            | "terr"
+            | "terrace"
+            | "the"
+            | "unit"
+            | "view"
+            | "villas"
+            | "walk"
+            | "way"
+            | "yard"
+    )
+}
+
+fn address_term_group(token: &str) -> Option<AddressTermGroup> {
+    if token.len() < 3 || is_numeric_address_token(token) || looks_like_postcode_fragment(token) {
+        return None;
+    }
+
+    let mut alternatives = Vec::new();
+    alternatives.push(token.to_string());
+    for alias in address_token_aliases(token) {
+        if !alternatives.iter().any(|existing| existing == alias) {
+            alternatives.push(alias.to_string());
+        }
+    }
+
+    if alternatives
+        .iter()
+        .all(|alternative| is_address_stop_token(alternative))
+    {
+        return None;
+    }
+
+    Some(AddressTermGroup { alternatives })
+}
+
+pub(super) fn address_search_tokens(text: &str) -> Vec<String> {
+    let mut tokens: Vec<String> = tokenize_address_text(text)
+        .into_iter()
+        .filter(|token| is_address_search_token(token))
+        .collect();
+    tokens.sort_unstable();
+    tokens.dedup();
+    tokens
+}
+
+fn is_address_search_token(token: &str) -> bool {
+    if looks_like_postcode_fragment(token) {
+        return false;
+    }
+
+    if is_numeric_address_token(token) {
+        return true;
+    }
+
+    if token.chars().any(|ch| ch.is_ascii_digit()) {
+        return token.len() >= 2;
+    }
+
+    token.len() >= 3
+}
+
+pub(super) fn is_address_candidate_token(token: &str) -> bool {
+    !is_numeric_address_token(token)
+        && !looks_like_postcode_fragment(token)
+        && (token.chars().any(|ch| ch.is_ascii_digit())
+            || (token.len() >= 3 && !is_address_stop_token(token)))
+}
+
+fn address_prefix_key(term: &str) -> &str {
+    if term.len() > ADDRESS_SEARCH_PREFIX_MAX_LEN {
+        &term[..ADDRESS_SEARCH_PREFIX_MAX_LEN]
+    } else {
+        term
+    }
+}
+
+pub(super) fn build_address_prefix_index(
+    address_token_index: &FxHashMap<String, Vec<u32>>,
+) -> FxHashMap<String, Vec<String>> {
+    let mut prefix_index: FxHashMap<String, Vec<String>> = FxHashMap::default();
+
+    for token in address_token_index.keys() {
+        let max_prefix_len = token.len().min(ADDRESS_SEARCH_PREFIX_MAX_LEN);
+        for prefix_len in ADDRESS_SEARCH_PREFIX_MIN_LEN..=max_prefix_len {
+            prefix_index
+                .entry(token[..prefix_len].to_string())
+                .or_default()
+                .push(token.clone());
+        }
+    }
+
+    for tokens in prefix_index.values_mut() {
+        tokens.sort_unstable();
+        tokens.dedup();
+    }
+
+    prefix_index
+}
+
+/// Intersect two ascending-sorted row-id slices.
+fn intersect_sorted(left: &[u32], right: &[u32]) -> Vec<u32> {
+    let mut out = Vec::new();
+    let (mut i, mut j) = (0, 0);
+    while i < left.len() && j < right.len() {
+        match left[i].cmp(&right[j]) {
+            std::cmp::Ordering::Less => i += 1,
+            std::cmp::Ordering::Greater => j += 1,
+            std::cmp::Ordering::Equal => {
+                out.push(left[i]);
+                i += 1;
+                j += 1;
+            }
+        }
+    }
+    out
+}
+
+/// Union two ascending-sorted row-id slices (deduplicated, stays sorted).
+fn union_sorted(left: &[u32], right: &[u32]) -> Vec<u32> {
+    let mut out = Vec::with_capacity(left.len() + right.len());
+    let (mut i, mut j) = (0, 0);
+    while i < left.len() && j < right.len() {
+        match left[i].cmp(&right[j]) {
+            std::cmp::Ordering::Less => {
+                out.push(left[i]);
+                i += 1;
+            }
+            std::cmp::Ordering::Greater => {
+                out.push(right[j]);
+                j += 1;
+            }
+            std::cmp::Ordering::Equal => {
+                out.push(left[i]);
+                i += 1;
+                j += 1;
+            }
+        }
+    }
+    out.extend_from_slice(&left[i..]);
+    out.extend_from_slice(&right[j..]);
+    out
+}
+
+/// An ordinal like "1st", "2nd", "3rd", "21st" — part of the street name ("2nd Avenue"), not a
+/// house-number prefix.
+fn is_ordinal_token(token: &str) -> bool {
+    let split = token.len().saturating_sub(2);
+    let (digits, suffix) = token.split_at(split);
+    !digits.is_empty()
+        && digits.chars().all(|ch| ch.is_ascii_digit())
+        && matches!(suffix, "st" | "nd" | "rd" | "th")
+}
+
+/// Leading address tokens that denote a unit/house number rather than the street itself.
+fn is_house_prefix_token(token: &str) -> bool {
+    if is_ordinal_token(token) {
+        return false;
+    }
+    matches!(
+        token,
+        "flat" | "fl" | "apartment" | "apt" | "unit" | "no" | "block" | "floor" | "room"
+    ) || token.len() == 1
+        || token.chars().all(|ch| ch.is_ascii_digit())
+        || (token.chars().next().is_some_and(|ch| ch.is_ascii_digit())
+            && token.chars().any(|ch| ch.is_ascii_alphabetic()))
+}
+
+/// Street-level key for an address: drops the leading house-number / flat prefix so that
+/// "12 Baker Street" and "5 Baker Street" collapse to a single street entry.
+fn street_key(address: &str) -> String {
+    let tokens = tokenize_address_text(address);
+    let mut start = 0;
+    while start < tokens.len() && is_house_prefix_token(&tokens[start]) {
+        start += 1;
+    }
+    if start >= tokens.len() {
+        return tokens.join(" ");
+    }
+    tokens[start..].join(" ")
+}
+
+/// Road-type words. Their presence (with no house number) marks a road browse, which we
+/// collapse to one result per street.
+const ROAD_TYPE_TOKENS: &[&str] = &[
+    "street",
+    "st",
+    "road",
+    "rd",
+    "lane",
+    "ln",
+    "avenue",
+    "ave",
+    "close",
+    "cl",
+    "drive",
+    "dr",
+    "way",
+    "court",
+    "ct",
+    "crescent",
+    "cres",
+    "place",
+    "terrace",
+    "terr",
+    "grove",
+    "gardens",
+    "gdns",
+    "walk",
+    "row",
+    "square",
+    "sq",
+    "hill",
+    "parade",
+    "mews",
+    "embankment",
+    "broadway",
+    "boulevard",
+    "blvd",
+];
+
+fn query_has_road_type(query: &str) -> bool {
+    tokenize_address_text(query)
+        .iter()
+        .any(|token| ROAD_TYPE_TOKENS.contains(&token.as_str()))
+}
+
+/// The outward code (everything before the space) of a canonical postcode.
+fn outcode_of(postcode: &str) -> &str {
+    postcode.split(' ').next().unwrap_or(postcode)
+}
+
+fn parse_address_query(query: &str) -> AddressQuery {
+    let tokens = tokenize_address_text(query);
+    let (full_postcode, postcode_token_indices) = extract_full_postcode(&tokens)
+        .map(|(postcode, indices)| (Some(postcode), indices))
+        .unwrap_or((None, Vec::new()));
+
+    let skip_postcode_tokens: FxHashSet<usize> = postcode_token_indices.into_iter().collect();
+
+    // Recover an appended partial postcode (outcode, or outcode + sector digit) as a ranking
+    // bias rather than discarding it — but only from the TRAILING position, so a leading road
+    // designation like "A4 Great West Road" is not mistaken for an area refinement.
+    let mut postcode_area: Option<String> = None;
+    let mut consumed_partial_tokens: FxHashSet<usize> = FxHashSet::default();
+    if full_postcode.is_none() && !tokens.is_empty() {
+        let last = tokens.len() - 1;
+        if !skip_postcode_tokens.contains(&last) {
+            let sector_digit =
+                tokens[last].len() == 1 && tokens[last].chars().all(|ch| ch.is_ascii_digit());
+            if last >= 1
+                && sector_digit
+                && !skip_postcode_tokens.contains(&(last - 1))
+                && looks_like_postcode_fragment(&tokens[last - 1])
+            {
+                postcode_area = Some(format!(
+                    "{}{}",
+                    tokens[last - 1].to_ascii_uppercase(),
+                    tokens[last]
+                ));
+                consumed_partial_tokens.insert(last);
+                consumed_partial_tokens.insert(last - 1);
+            } else if looks_like_postcode_fragment(&tokens[last]) {
+                postcode_area = Some(tokens[last].to_ascii_uppercase());
+                consumed_partial_tokens.insert(last);
+            }
+        }
+    }
+
+    let mut text_groups = Vec::new();
+    let mut numeric_terms = Vec::new();
+    let mut candidate_terms = Vec::new();
+
+    for (idx, token) in tokens.iter().enumerate() {
+        if skip_postcode_tokens.contains(&idx)
+            || consumed_partial_tokens.contains(&idx)
+            || looks_like_postcode_fragment(token)
+        {
+            continue;
+        }
+
+        if is_numeric_address_token(token) {
+            numeric_terms.push(token.clone());
+            continue;
+        }
+
+        if let Some(group) = address_term_group(token) {
+            for alternative in &group.alternatives {
+                if !is_address_stop_token(alternative)
+                    && !candidate_terms.iter().any(|term| term == alternative)
+                {
+                    candidate_terms.push(alternative.clone());
+                }
+            }
+            text_groups.push(group);
+        } else if token.chars().any(|ch| ch.is_ascii_digit()) && token.len() >= 2 {
+            numeric_terms.push(token.clone());
+            if !candidate_terms.iter().any(|term| term == token) {
+                candidate_terms.push(token.clone());
+            }
+        }
+    }
+
+    text_groups.dedup_by(|left, right| left.alternatives == right.alternatives);
+    numeric_terms.sort_unstable();
+    numeric_terms.dedup();
+
+    AddressQuery {
+        full_postcode,
+        postcode_area,
+        text_groups,
+        numeric_terms,
+        candidate_terms,
+    }
+}
+
+fn token_matches_query_term(token: &str, query_term: &str) -> bool {
+    token == query_term || (query_term.len() >= 3 && token.starts_with(query_term))
+}
+
+fn token_matches_numeric_term(token: &str, query_term: &str) -> bool {
+    token == query_term || token.starts_with(query_term)
+}
+
+#[cfg(test)]
+fn address_tokens_match_group(tokens: &[String], group: &AddressTermGroup) -> bool {
+    group.alternatives.iter().any(|alternative| {
+        tokens
+            .iter()
+            .any(|token| token_matches_query_term(token, alternative))
+    })
+}
+
+impl PropertyData {
+    fn row_address_search_tokens(&self, row: usize) -> &[lasso::Spur] {
+        let offset = self.address_search_token_offsets[row] as usize;
+        let length = self.address_search_token_lengths[row] as usize;
+        &self.address_search_token_keys[offset..offset + length]
+    }
+
+    /// Search individual property addresses, returning `(row, score)` ranked best-first.
+    ///
+    /// Candidate rows come from intersecting the posting lists of the distinctive words the
+    /// user typed in full (so "Cherry Hinton Road" narrows to rows containing both), unioned
+    /// with the exact-postcode rows when a complete postcode is present (so a postcode is a
+    /// boost, not an all-or-nothing gate). An appended partial postcode keeps in-area rows
+    /// ahead of the candidate cut and adds a scoring bias. With a road-type word and no house
+    /// number, results collapse to one row per street.
+    pub fn search_addresses(&self, query: &str, limit: usize) -> Vec<(usize, i32)> {
+        if limit == 0 {
+            return Vec::new();
+        }
+
+        let parsed = parse_address_query(query);
+        if parsed.full_postcode.is_none()
+            && parsed.text_groups.is_empty()
+            && parsed.numeric_terms.is_empty()
+        {
+            return Vec::new();
+        }
+
+        let mut candidate_rows = self.address_candidate_rows(&parsed.candidate_terms);
+
+        // A complete postcode contributes its rows too, instead of replacing the road match.
+        if let Some(postcode) = parsed.full_postcode.as_deref() {
+            if let Some(rows) = self
+                .postcode_interner
+                .get(postcode)
+                .and_then(|key| self.postcode_row_index.get(&key))
+            {
+                candidate_rows = if candidate_rows.is_empty() {
+                    rows.clone()
+                } else {
+                    union_sorted(&candidate_rows, rows)
+                };
+            }
+        }
+
+        if candidate_rows.is_empty() {
+            return Vec::new();
+        }
+
+        // When the user appended a partial postcode, keep in-area rows ahead of the cut so the
+        // refinement still surfaces even for very common roads. Single pass (stable partition) so
+        // the postcode check — which allocates — runs exactly once per candidate.
+        if let Some(area) = parsed.postcode_area.as_deref() {
+            let mut in_area = Vec::new();
+            let mut others = Vec::new();
+            for &row in &candidate_rows {
+                if self.row_postcode_in_area(row as usize, area) {
+                    in_area.push(row);
+                } else {
+                    others.push(row);
+                }
+            }
+            in_area.extend(others);
+            candidate_rows = in_area;
+        }
+        candidate_rows.truncate(ADDRESS_SEARCH_CANDIDATE_LIMIT);
+
+        let mut scored: Vec<(i32, usize, usize)> = candidate_rows
+            .into_iter()
+            .filter_map(|row| {
+                let row = row as usize;
+                self.address_match_score(row, &parsed)
+                    .map(|score| (score, self.address(row).len(), row))
+            })
+            .collect();
+
+        scored.sort_unstable_by(|left, right| {
+            right
+                .0
+                .cmp(&left.0)
+                .then(left.1.cmp(&right.1))
+                .then(left.2.cmp(&right.2))
+        });
+
+        // Collapse a road browse (road-type word, no house number) to one row per street.
+        let collapse_streets = parsed.numeric_terms.is_empty() && query_has_road_type(query);
+
+        let mut seen = FxHashSet::default();
+        let mut results = Vec::with_capacity(limit);
+        for (score, _, row) in scored {
+            let address = self.address(row).trim();
+            if address.is_empty() {
+                continue;
+            }
+            let key = if collapse_streets {
+                format!(
+                    "{}\n{}",
+                    street_key(address),
+                    outcode_of(self.postcode(row))
+                )
+            } else {
+                format!("{}\n{}", address.to_ascii_lowercase(), self.postcode(row))
+            };
+            if !seen.insert(key) {
+                continue;
+            }
+            results.push((row, score));
+            if results.len() == limit {
+                break;
+            }
+        }
+
+        results
+    }
+
+    /// True when the row's postcode begins with the compact partial-postcode `area`
+    /// (e.g. "NW1" or "NW16" matches "NW1 6XE").
+    fn row_postcode_in_area(&self, row: usize, area: &str) -> bool {
+        let mut compact = String::new();
+        for ch in self.postcode(row).chars() {
+            if !ch.is_whitespace() {
+                compact.push(ch.to_ascii_uppercase());
+            }
+        }
+        compact.starts_with(area)
+    }
+
+    /// Candidate rows for the distinctive query words. Words typed in full intersect by their
+    /// exact posting lists (precise); a still-being-typed final word with no exact match seeds
+    /// from the smallest prefix-expanded posting list (so partial typing keeps working).
+    fn address_candidate_rows(&self, terms: &[String]) -> Vec<u32> {
+        let mut exact: Vec<&[u32]> = terms
+            .iter()
+            .filter_map(|term| self.address_token_index.get(term).map(Vec::as_slice))
+            .collect();
+
+        if !exact.is_empty() {
+            exact.sort_by_key(|rows| rows.len());
+            let mut acc = exact[0].to_vec();
+            for rows in &exact[1..] {
+                if acc.is_empty() {
+                    break;
+                }
+                acc = intersect_sorted(&acc, rows);
+            }
+            return acc;
+        }
+
+        self.prefix_seed_rows(terms)
+    }
+
+    /// Seed rows from the smallest prefix-expanded term — used only when no word matched an
+    /// indexed token exactly (i.e. the user is still typing the final word).
+    fn prefix_seed_rows(&self, terms: &[String]) -> Vec<u32> {
+        let mut best: Option<Vec<u32>> = None;
+        for term in terms {
+            if term.len() < ADDRESS_SEARCH_PREFIX_MIN_LEN {
+                continue;
+            }
+            let Some(tokens) = self.address_prefix_index.get(address_prefix_key(term)) else {
+                continue;
+            };
+            let mut union: Vec<u32> = Vec::new();
+            for token in tokens {
+                if !token.starts_with(term) {
+                    continue;
+                }
+                if let Some(rows) = self.address_token_index.get(token) {
+                    union = if union.is_empty() {
+                        rows.clone()
+                    } else {
+                        union_sorted(&union, rows)
+                    };
+                }
+            }
+            if !union.is_empty()
+                && best
+                    .as_ref()
+                    .is_none_or(|current| union.len() < current.len())
+            {
+                best = Some(union);
+            }
+        }
+        best.unwrap_or_default()
+    }
+
+    fn address_match_score(&self, row: usize, parsed: &AddressQuery) -> Option<i32> {
+        if self.address(row).trim().is_empty() {
+            return None;
+        }
+
+        let tokens = self.row_address_search_tokens(row);
+        if parsed
+            .text_groups
+            .iter()
+            .any(|group| !self.address_tokens_match_group(tokens, group))
+        {
+            return None;
+        }
+
+        let numeric_matches = parsed
+            .numeric_terms
+            .iter()
+            .filter(|term| {
+                tokens.iter().any(|token| {
+                    token_matches_numeric_term(self.address_search_interner.resolve(token), term)
+                })
+            })
+            .count();
+
+        if !parsed.numeric_terms.is_empty() && numeric_matches == 0 {
+            return None;
+        }
+
+        let mut score = 0;
+        if parsed.full_postcode.is_some() {
+            score += 1_000;
+        }
+        score += (parsed.text_groups.len() as i32) * 200;
+        score += (numeric_matches as i32) * 90;
+        if numeric_matches == parsed.numeric_terms.len() && numeric_matches > 0 {
+            score += 50;
+        }
+        // Additive bias (never a filter) when the row sits in the appended partial postcode.
+        if let Some(area) = parsed.postcode_area.as_deref() {
+            if self.row_postcode_in_area(row, area) {
+                score += 400;
+            }
+        }
+
+        Some(score)
+    }
+
+    fn address_tokens_match_group(&self, tokens: &[lasso::Spur], group: &AddressTermGroup) -> bool {
+        group.alternatives.iter().any(|alternative| {
+            tokens.iter().any(|token| {
+                token_matches_query_term(self.address_search_interner.resolve(token), alternative)
+            })
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn full_postcode_detection_accepts_common_formats() {
+        assert!(is_full_postcode_compact("SW1A1AA"));
+        assert!(is_full_postcode_compact("E142DG"));
+        assert!(is_full_postcode_compact("M11AE"));
+        assert!(!is_full_postcode_compact("E14"));
+        assert!(!is_full_postcode_compact("DOWNING"));
+        assert!(!is_full_postcode_compact("10A"));
+    }
+
+    #[test]
+    fn address_query_parsing_skips_postcodes_and_street_suffixes() {
+        let parsed = parse_address_query("Flat 2, 10 Downing St, SW1A 2AA");
+
+        assert_eq!(parsed.full_postcode.as_deref(), Some("SW1A 2AA"));
+        assert_eq!(
+            parsed.numeric_terms,
+            vec!["10".to_string(), "2".to_string()]
+        );
+        assert_eq!(parsed.candidate_terms, vec!["downing".to_string()]);
+        assert_eq!(parsed.text_groups.len(), 1);
+        assert_eq!(
+            parsed.text_groups[0].alternatives,
+            vec!["downing".to_string()]
+        );
+    }
+
+    #[test]
+    fn address_query_parsing_handles_compact_postcodes() {
+        let parsed = parse_address_query("10 downing street sw1a1aa");
+
+        assert_eq!(parsed.full_postcode.as_deref(), Some("SW1A 1AA"));
+        assert_eq!(parsed.numeric_terms, vec!["10".to_string()]);
+        assert_eq!(parsed.candidate_terms, vec!["downing".to_string()]);
+    }
+
+    #[test]
+    fn address_query_recovers_appended_partial_postcode_as_bias() {
+        let parsed = parse_address_query("Baker Street NW1");
+        assert_eq!(parsed.full_postcode, None);
+        assert_eq!(parsed.postcode_area.as_deref(), Some("NW1"));
+        // The road words are still searchable; the postcode fragment did not consume them.
+        assert_eq!(parsed.candidate_terms, vec!["baker".to_string()]);
+        assert!(parsed.numeric_terms.is_empty());
+    }
+
+    #[test]
+    fn address_query_recovers_outcode_plus_sector_without_a_phantom_house_number() {
+        let parsed = parse_address_query("High Street CR0 2");
+        assert_eq!(parsed.postcode_area.as_deref(), Some("CR02"));
+        // The lone sector digit must not be treated as a house number.
+        assert!(parsed.numeric_terms.is_empty());
+        assert_eq!(parsed.candidate_terms, vec!["high".to_string()]);
+    }
+
+    #[test]
+    fn full_postcode_takes_precedence_over_partial_bias() {
+        let parsed = parse_address_query("Baker Street NW1 6XE");
+        assert_eq!(parsed.full_postcode.as_deref(), Some("NW1 6XE"));
+        assert_eq!(parsed.postcode_area, None);
+    }
+
+    #[test]
+    fn intersect_and_union_sorted_row_ids() {
+        assert_eq!(
+            intersect_sorted(&[1, 2, 3, 5], &[2, 3, 4, 5]),
+            vec![2, 3, 5]
+        );
+        assert_eq!(intersect_sorted(&[1, 2], &[3, 4]), Vec::<u32>::new());
+        assert_eq!(union_sorted(&[1, 3, 5], &[2, 3, 4]), vec![1, 2, 3, 4, 5]);
+        assert_eq!(union_sorted(&[], &[2, 4]), vec![2, 4]);
+    }
+
+    #[test]
+    fn street_key_collapses_house_numbers_and_flats() {
+        assert_eq!(street_key("12 Baker Street"), "baker street");
+        assert_eq!(street_key("5 Baker Street"), "baker street");
+        assert_eq!(street_key("Flat 2, 10 Downing Street"), "downing street");
+        assert_eq!(street_key("221B Baker Street"), "baker street");
+    }
+
+    #[test]
+    fn street_key_keeps_ordinal_street_names() {
+        // Ordinals are part of the street name, not a house-number prefix.
+        assert_eq!(street_key("2nd Avenue"), "2nd avenue");
+        assert_eq!(street_key("12 3rd Avenue"), "3rd avenue");
+        assert!(is_ordinal_token("21st"));
+        assert!(!is_ordinal_token("21"));
+        assert!(!is_ordinal_token("221b"));
+    }
+
+    #[test]
+    fn postcode_area_recovered_only_from_the_trailing_position() {
+        // A leading road designation must NOT be taken as an area refinement.
+        let parsed = parse_address_query("A4 Great West Road");
+        assert_eq!(parsed.postcode_area, None);
+        // A genuine trailing outcode still is.
+        let trailing = parse_address_query("Great West Road W4");
+        assert_eq!(trailing.postcode_area.as_deref(), Some("W4"));
+    }
+
+    #[test]
+    fn road_type_detection() {
+        assert!(query_has_road_type("high street"));
+        assert!(query_has_road_type("acacia avenue"));
+        assert!(!query_has_road_type("acacia"));
+        assert!(!query_has_road_type("london"));
+    }
+
+    #[test]
+    fn address_query_parsing_keeps_partial_terms_for_row_matching() {
+        let parsed = parse_address_query("settlers cour");
+
+        assert_eq!(parsed.full_postcode, None);
+        assert_eq!(parsed.numeric_terms, Vec::<String>::new());
+        assert_eq!(
+            parsed.candidate_terms,
+            vec!["settlers".to_string(), "cour".to_string()]
+        );
+        assert_eq!(parsed.text_groups.len(), 2);
+        assert_eq!(
+            parsed.text_groups[0].alternatives,
+            vec!["settlers".to_string()]
+        );
+        assert_eq!(parsed.text_groups[1].alternatives, vec!["cour".to_string()]);
+    }
+
+    #[test]
+    fn address_search_tokens_keep_actual_address_terms_for_scoring() {
+        let tokens = address_search_tokens("Flat 2, 10 Downing Cour");
+
+        assert_eq!(
+            tokens,
+            vec![
+                "10".to_string(),
+                "2".to_string(),
+                "cour".to_string(),
+                "downing".to_string(),
+                "flat".to_string()
+            ]
+        );
+    }
+
+    #[test]
+    fn address_prefix_index_finds_partial_address_terms() {
+        let mut token_index: FxHashMap<String, Vec<u32>> = FxHashMap::default();
+        token_index.insert("downing".to_string(), vec![1]);
+        token_index.insert("downton".to_string(), vec![2]);
+        token_index.insert("market".to_string(), vec![3]);
+
+        let prefix_index = build_address_prefix_index(&token_index);
+
+        assert_eq!(
+            prefix_index.get("down").cloned().unwrap_or_default(),
+            vec!["downing".to_string(), "downton".to_string()]
+        );
+        assert_eq!(
+            prefix_index.get("downi").cloned().unwrap_or_default(),
+            vec!["downing".to_string()]
+        );
+        assert_eq!(
+            prefix_index.get("downt").cloned().unwrap_or_default(),
+            vec!["downton".to_string()]
+        );
+        assert!(!prefix_index.contains_key("do"));
+    }
+
+    #[test]
+    fn address_term_matching_allows_prefixes_and_aliases() {
+        let tokens = tokenize_address_text("10 Downing Street");
+        let prefix_group = address_term_group("down").expect("prefix term should be searchable");
+        let alias_group = AddressTermGroup {
+            alternatives: vec!["st".to_string(), "street".to_string()],
+        };
+
+        assert!(address_tokens_match_group(&tokens, &prefix_group));
+        assert!(address_tokens_match_group(&tokens, &alias_group));
+    }
+
+    #[test]
+    fn address_term_matching_uses_actual_token_prefixes() {
+        let tokens = tokenize_address_text("12 Settlers Court");
+        let prefix_group = address_term_group("cou").expect("partial term should be searchable");
+
+        assert!(address_tokens_match_group(&tokens, &prefix_group));
+    }
+}