From b4112c311ce9f54a8982bcdfa95105a67bf23910 Mon Sep 17 00:00:00 2001
From: Book-reader <thevoid@outlook.co.nz>
Date: Fri, 9 May 2025 09:53:28 +1200
Subject: [PATCH] initial spellcheck implementation

---
 asklyphe-frontend/src/main.rs          |   1 +
 asklyphe-frontend/src/routes/search.rs |   7 +-
 asklyphe-frontend/src/spellcheck.rs    | 113 +++++++++++++++++++++++++
 3 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 asklyphe-frontend/src/spellcheck.rs

diff --git a/asklyphe-frontend/src/main.rs b/asklyphe-frontend/src/main.rs
index 2b87121..6e5b782 100644
--- a/asklyphe-frontend/src/main.rs
+++ b/asklyphe-frontend/src/main.rs
@@ -14,6 +14,7 @@
 pub mod searchbot;
 pub mod wikipedia;
 pub mod unit_converter;
+pub mod spellcheck;
 pub mod routes;
 
 use std::{env, process};
diff --git a/asklyphe-frontend/src/routes/search.rs b/asklyphe-frontend/src/routes/search.rs
index f1d43b7..c979062 100644
--- a/asklyphe-frontend/src/routes/search.rs
+++ b/asklyphe-frontend/src/routes/search.rs
@@ -18,6 +18,7 @@ use crate::unit_converter;
 use crate::unit_converter::UnitConversion;
 use crate::wikipedia::WikipediaSummary;
 use crate::{wikipedia, Opts, ALPHA, BUILT_ON, GIT_COMMIT, VERSION, YEAR};
+use crate::spellcheck;
 use askama::Template;
 use asklyphe_common::nats;
 use asklyphe_common::nats::bingservice::{
@@ -158,18 +159,20 @@ pub async fn search_js(
         let mut complications = Complications::default();
         // todo: better way of specifying that user doesn't want complications
         if !query.contains("-complications") {
-            let mut wikiquery = query.clone().to_lowercase();
+            /*let mut wikiquery = query.clone().to_lowercase();
             wikiquery.retain(|c| c.is_alphanumeric() || c.is_ascii_whitespace());
             wikiquery = wikiquery.replace(' ', "%20");
             // todo: proper url escaping
             let wikipedia_comp =
                 tokio::spawn(async move { wikipedia::get_wikipedia_page(&wikiquery, 20).await });
-            complications.wikipedia = wikipedia_comp.await.unwrap_or_default();
+            complications.wikipedia = wikipedia_comp.await.unwrap_or_default();*/
 
             let mut unit_query = query.clone().to_lowercase();
             unit_query = unit_query.replace("metre", "meter");
             let unit_comp = unit_converter::convert_unit(&unit_query);
             complications.unit_converter = unit_comp;
+
+            let corrections = spellcheck::check(&query);
         } else {
             complications.disabled = true;
             query = query.replace("-complications", "");
diff --git a/asklyphe-frontend/src/spellcheck.rs b/asklyphe-frontend/src/spellcheck.rs
new file mode 100644
index 0000000..187cc32
--- /dev/null
+++ b/asklyphe-frontend/src/spellcheck.rs
@@ -0,0 +1,113 @@
+use tracing::{debug, error};
+use std::{cmp, mem};
+// use tokio::sync::{Mutex, RwLock};
+
+include!("./google-10000-english-no-swears.txt");
+
+// max distance before no alternatives are considered
+const MAX_DISTANCE: usize = 6;
+
+pub fn check(query: &String) -> Vec<String> {
+	error!("Query: {}", query);
+	let distances = query.split(" ")
+		.map(|qword| qword.to_lowercase())
+		.map(
+			|qword|
+			KNOWN_WORDS.iter()
+				.map(
+					|kword|
+					(qword.clone(), kword, levenshtein_distance(&qword, kword)))
+						.map(|val| (val.0, val.1, val.2))
+						.min_by(|a, b| a.2.cmp(&b.2)).unwrap()
+		).filter(|(_, _, d)| *d > 0)
+		.for_each(|word| {
+			debug!("instead of '{}' did you mean '{}'? (distance of {})", word.0, word.1, word.2);
+		});
+		// .collect::<Vec<_>>();
+
+	// distances
+	vec![]
+}
+
+// cost of 2 for add/remove, cost of 1 for replace
+fn levenshtein_distance(a: &str, other: &str) -> usize {
+	let mut dist = vec![0usize; other.len() + 1];
+	let mut dist_prev = vec![0usize; other.len() + 1];
+
+	for i in 0..=other.len() {
+		dist_prev[i] = i;
+	}
+
+	for i in 1..=a.len() {
+		dist[0] = i;
+
+		for j in 1..=other.len() {
+			if a.get(i - 1..i).unwrap() == other.get(j - 1..j).unwrap() {
+				dist[j] = dist_prev[j - 1];
+			} else {
+				dist[j] = 1 + cmp::min(
+					dist.get(j - 1).unwrap(),
+					cmp::min(dist_prev.get(j).unwrap(), dist_prev.get(j - 1).unwrap()));
+			}
+		}
+		// let temp = dist_prev;
+		// dist_prev = dist.clone();
+		// dist = temp;
+		// dist_prev = dist;
+		// dist = vec![0usize; max_len];
+		mem::swap(&mut dist, &mut dist_prev);
+	}
+	dist_prev[other.len()]
+
+	
+
+	/*let mut distances = vec![vec![0usize; other.len() + 1]; a.len() + 1];
+	for i in 1..=a.len() {
+		distances[i][0] = i;
+	}
+
+	for j in 1..=other.len() {
+		distances[0][j] = j;
+	}
+
+	/*unsafe {
+	for i in 1..=a.len() {
+		for j in 1..=other.len() {
+			if *a.get_unchecked(i - 1..i) == *other.get_unchecked(j - 1..j) {
+				// 0
+				distances[i][j] = *distances.get_unchecked(i - 1).get_unchecked(j - 1);
+			} else {
+				// 1
+				distances[i][j] = 1 + cmp::min(
+					(*distances.get_unchecked(i - 1).get_unchecked(j - 1)),
+					cmp::min(
+						(*distances.get_unchecked(i - 1).get_unchecked(j)),
+						(*distances.get_unchecked(i).get_unchecked(j - 1))
+					)
+				);
+			}
+		}
+	}
+	}*/
+
+
+	for i in 1..=a.len()  {
+		for j in 1..=other.len() {
+			if a.get(i - 1..i).unwrap() == other.get(j - 1..j).unwrap() {
+				// 0
+				distances[i][j] = *distances.get(i - 1).unwrap().get(j - 1).unwrap();
+			} else {
+				// 1
+				distances[i][j] = 1 + cmp::min(
+					(*distances.get(i - 1).unwrap().get(j - 1).unwrap()),
+					cmp::min(
+						(*distances.get(i - 1).unwrap().get(j).unwrap()),
+						(*distances.get(i).unwrap().get(j - 1).unwrap())
+					)
+				);
+			}
+		}
+	}
+	*distances.get(a.len()).unwrap().get(other.len()).unwrap()*/
+}
+