From 11fda4e11fb6b4926334f15db4ffecd3f8f589d0 Mon Sep 17 00:00:00 2001
From: PhatPhuckDave <david.majdandzic@hotmail.com>
Date: Sun, 10 Aug 2025 22:29:15 +0200
Subject: [PATCH] feat(search): implement Aho-Corasick for efficient substring
 searching and improve result ordering

---
 frontend/src/components/SearchDialog.tsx | 18 ++++++++++------
 frontend/src/lib/aho.ts                  | 27 +++++++++++++++++++++---
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/frontend/src/components/SearchDialog.tsx b/frontend/src/components/SearchDialog.tsx
index 41a82a3..2684699 100644
--- a/frontend/src/components/SearchDialog.tsx
+++ b/frontend/src/components/SearchDialog.tsx
@@ -59,15 +59,19 @@ export const SearchDialog: React.FC = () => {
   }, [open, all.length]);
 
   useEffect(() => {
-    if (query.trim().length === 0) { setResults([]); return; }
-    const out: Array<SearchResult> = [];
+    const q = query.trim().toLowerCase();
+    if (q.length === 0) { setResults([]); return; }
+    const scored: Array<{ s: SearchResult; idx: number }> = [];
     for (const r of all) {
-      if (automaton.searchHas(r.system.toLowerCase())) {
-        out.push(r);
-        if (out.length >= 10) break;
-      }
+      const idx = automaton.searchFirstIndex(r.system.toLowerCase());
+      if (idx >= 0) scored.push({ s: r, idx });
     }
-    setResults(out);
+    scored.sort((a, b) => {
+      if (a.idx !== b.idx) return a.idx - b.idx; // earlier index first
+      if (a.s.system.length !== b.s.system.length) return a.s.system.length - b.s.system.length; // shorter name next
+      return a.s.system.localeCompare(b.s.system);
+    });
+    setResults(scored.slice(0, 10).map(x => x.s));
   }, [query, all, automaton]);
 
   const onSelect = (r: SearchResult) => {
diff --git a/frontend/src/lib/aho.ts b/frontend/src/lib/aho.ts
index 3e54af4..c07b910 100644
--- a/frontend/src/lib/aho.ts
+++ b/frontend/src/lib/aho.ts
@@ -1,6 +1,7 @@
 export class AhoCorasick {
   private goto: Array<Map<string, number>> = [new Map()];
   private out: Array<boolean> = [false];
+  private outLen: Array<number> = [0];
   private fail: Array<number> = [0];
 
   add(pattern: string) {
@@ -12,6 +13,7 @@ export class AhoCorasick {
         this.goto[state].set(ch, newState);
         this.goto.push(new Map());
         this.out.push(false);
+        this.outLen.push(0);
         this.fail.push(0);
         state = newState;
       } else {
@@ -19,16 +21,15 @@ export class AhoCorasick {
       }
     }
     this.out[state] = true;
+    this.outLen[state] = Math.max(this.outLen[state], pattern.length);
   }
 
   build() {
     const queue: number[] = [];
-    // Initialize depth 1 states
-    for (const [ch, s] of this.goto[0]) {
+    for (const [, s] of this.goto[0]) {
       this.fail[s] = 0;
       queue.push(s);
     }
-    // BFS
     while (queue.length > 0) {
       const r = queue.shift()!;
       for (const [a, s] of this.goto[r]) {
@@ -40,6 +41,7 @@ export class AhoCorasick {
         const f = this.goto[state].get(a) ?? 0;
         this.fail[s] = f;
         this.out[s] = this.out[s] || this.out[f];
+        if (this.outLen[f] > this.outLen[s]) this.outLen[s] = this.outLen[f];
       }
     }
   }
@@ -56,4 +58,23 @@ export class AhoCorasick {
     }
     return false;
   }
+
+  // Returns the starting index of the first match in text, or -1 if none
+  searchFirstIndex(text: string): number {
+    let state = 0;
+    let i = 0;
+    for (const ch of text) {
+      while (state !== 0 && !this.goto[state].has(ch)) {
+        state = this.fail[state];
+      }
+      state = this.goto[state].get(ch) ?? 0;
+      if (this.out[state]) {
+        const len = this.outLen[state] || 0;
+        if (len > 0) return i - len + 1;
+        return i; // fallback
+      }
+      i++;
+    }
+    return -1;
+  }
 } 
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