From 60562d62856c114f23c183f7873fe1c809f4c7b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vilius=20=C5=A0umskas?= <vilius@sumskas.eu>
Date: Mon, 1 Nov 2021 00:07:34 +0200
Subject: [PATCH] Add configurable Levenshtein distance for fuzzy search (#124)

* Add configurable Levenshtein distance for fuzzy search

* Style fix
---
 README.md                 | 2 ++
 blueprints.yaml           | 7 +++++++
 classes/GravTNTSearch.php | 3 +++
 tntsearch.yaml            | 1 +
 4 files changed, 13 insertions(+)

diff --git a/README.md b/README.md
index f6a35ce..e9541ce 100644
--- a/README.md
+++ b/README.md
@@ -68,6 +68,7 @@ built_in_search_page: true
 enable_admin_page_events: true
 search_type: auto
 fuzzy: false
+distance: 2
 phrases: true
 stemmer: 'no'
 display_route: true
@@ -103,6 +104,7 @@ The configuration options are as follows:
   * `boolean` - supports `or` or `minus`. e.g. `foo -bar`
   * `auto` - automatically detects whether to use `basic` or `boolean`
 * `fuzzy` - matches if the words are 'close' but not necessarily exact matches
+* `distance` - Levenshtein distance of fuzzy search. It represents the amount of characters which need to be changed, removed, or added in a word in order it to match the search keyword. Increasing the distance produces more search results but decreases the accuracy of the search.
 * `phrases` - automatically handle phrases support
 * `stemmer` - can be one of these types:
   * `no` - no stemmer
diff --git a/blueprints.yaml b/blueprints.yaml
index 455e49b..faa3772 100644
--- a/blueprints.yaml
+++ b/blueprints.yaml
@@ -157,6 +157,13 @@ form:
       validate:
         type: bool
 
+    distance:
+      type: number
+      size: x-small
+      label: Levenshtein distance of fuzzy search
+      help: It represents the amount of characters which need to be changed, removed, or added in a word in order it to match the search keyword. Increasing the distance produces more search results but decreases the accuracy of the search.
+      default: 2
+
     phrases:
       type: toggle
       label: Match quoted phrases
diff --git a/classes/GravTNTSearch.php b/classes/GravTNTSearch.php
index 6f78e4f..864856d 100644
--- a/classes/GravTNTSearch.php
+++ b/classes/GravTNTSearch.php
@@ -43,6 +43,7 @@ public function __construct($options = [])
 
         $search_type = $config->get('plugins.tntsearch.search_type', 'auto');
         $fuzzy = $config->get('plugins.tntsearch.fuzzy', false);
+        $distance = $config->get('plugins.tntsearch.distance', 2);
         $stemmer = $config->get('plugins.tntsearch.stemmer', 'no');
         $limit = $config->get('plugins.tntsearch.limit', 20);
         $snippet = $config->get('plugins.tntsearch.snippet', 300);
@@ -66,6 +67,7 @@ public function __construct($options = [])
             'json' => false,
             'search_type' => $search_type,
             'fuzzy' => $fuzzy,
+            'distance' => $distance,
             'stemmer' => $stemmer,
             'limit' => $limit,
             'as_you_type' => true,
@@ -99,6 +101,7 @@ public function search($query)
 
         if (isset($this->options['fuzzy']) && $this->options['fuzzy']) {
             $this->tnt->fuzziness = true;
+            $this->tnt->fuzzy_distance = $this->options['distance'];
         }
 
         $limit = (int)$this->options['limit'];
diff --git a/tntsearch.yaml b/tntsearch.yaml
index c2647ab..c0df206 100644
--- a/tntsearch.yaml
+++ b/tntsearch.yaml
@@ -7,6 +7,7 @@ built_in_search_page: true
 enable_admin_page_events: true
 search_type: auto
 fuzzy: false
+distance: 2
 phrases: true
 stemmer: default
 display_route: true