From bf629dfabd0587447384bda4b997760478b302a0 Mon Sep 17 00:00:00 2001
From: Guy Sartorelli <guy.sartorelli@silverstripe.com>
Date: Sat, 4 Dec 2021 18:43:36 +0100
Subject: [PATCH] ENH Split sentences by configurable punctuation for summary

Co-authored-by: Lukas Erni <le@kraftausdruck.ch>
---
 src/ORM/FieldType/DBText.php | 21 ++++++++++++++----
 tests/php/ORM/DBTextTest.php | 43 ++++++++++++++++++++++++++++++++----
 2 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/src/ORM/FieldType/DBText.php b/src/ORM/FieldType/DBText.php
index ce60aa295..f00252585 100644
--- a/src/ORM/FieldType/DBText.php
+++ b/src/ORM/FieldType/DBText.php
@@ -37,6 +37,11 @@ class DBText extends DBString
         'Summary' => 'Text',
     ];
 
+    /**
+     * Punctuation that marks an end of a sentence for the Summary() method
+     */
+    private static array $summary_sentence_separators = ['.', '?', '!'];
+
     /**
      * (non-PHPdoc)
      * @see DBField::requireField()
@@ -130,10 +135,18 @@ class DBText extends DBString
             $add = $this->defaultEllipsis();
         }
 
-        // Split on sentences (don't remove period)
-        $sentences = array_filter(array_map(function ($str) {
-            return trim($str ?? '');
-        }, preg_split('@(?<=\.)@', $value ?? '') ?: []));
+        // Split on sentences (don't remove punctuation)
+        $summarySentenceSeparators = preg_quote(implode(static::config()->get('summary_sentence_separators')), '@');
+        $possibleSentences = preg_split('@(?<=[' . $summarySentenceSeparators . '])@', $value ?? '') ?: [];
+        $sentences = [];
+
+        foreach ($possibleSentences as $sentence) {
+            $sentence = trim($sentence);
+            if ($sentence) {
+                $sentences[] = $sentence;
+            }
+        }
+
         $wordCount = count(preg_split('#\s+#u', $sentences[0] ?? '') ?: []);
 
         // if the first sentence is too long, show only the first $maxWords words
diff --git a/tests/php/ORM/DBTextTest.php b/tests/php/ORM/DBTextTest.php
index 7a2a1888e..cb2f0fa48 100644
--- a/tests/php/ORM/DBTextTest.php
+++ b/tests/php/ORM/DBTextTest.php
@@ -282,32 +282,56 @@ class DBTextTest extends SapphireTest
     public function providerSummary()
     {
         return [
-            [
+            'simple test' => [
                 'This is some text. It is a test',
                 3,
                 false,
                 'This is some…',
             ],
-            [
+            'custom ellipses' => [
                 // check custom ellipsis
                 'This is a test text in a longer sentence and a custom ellipsis.',
                 8,
                 '...', // regular dots instead of the ellipsis character
                 'This is a test text in a longer...',
             ],
-            [
+            'umlauts' => [
                 'both schön and können have umlauts',
                 5,
                 false,
                 'both schön and können have…',
             ],
-            [
+            'invalid UTF' => [
                 // check invalid UTF8 handling — input is an invalid UTF sequence, output should be empty string
                 "\xf0\x28\x8c\xbc",
                 50,
                 false,
                 '',
             ],
+            'treats period as sentence boundary' => [
+                'This is some text. It is a test. There are three sentences.',
+                10,
+                false,
+                'This is some text. It is a test.',
+            ],
+            'treats exclamation mark as sentence boundary' => [
+                'This is some text! It is a test! There are three sentences.',
+                10,
+                false,
+                'This is some text! It is a test!',
+            ],
+            'treats question mark as sentence boundary' => [
+                'This is some text? It is a test? There are three sentences.',
+                10,
+                false,
+                'This is some text? It is a test?',
+            ],
+            'does not treat colon as sentence boundary' => [
+                'This is some text: It is a test: There are three sentences.',
+                10,
+                false,
+                'This is some text: It is a test: There are…',
+            ],
         ];
     }
 
@@ -401,4 +425,15 @@ class DBTextTest extends SapphireTest
         $result = $text->obj('Summary', [$words, $add])->forTemplate();
         $this->assertEquals($expectedValue, $result);
     }
+
+    public function testSummaryConfiguration()
+    {
+        $text = DBField::create_field(DBText::class, 'This is some text: It is a test: There are three sentences.');
+        // Doesn't treat colon as a boundary by default
+        $this->assertSame('This is some text: It is a test: There are…', $text->Summary(10));
+
+        DBText::config()->merge('summary_sentence_separators', [':']);
+        // Does treat colon as a boundary if configured to do so
+        $this->assertSame('This is some text: It is a test:', $text->Summary(10));
+    }
 }