refactor(classifier): single-pass hard-drop trigger; cleaner drop reason rendering

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/class-classifier.php

@@ -160,27 +160,17 @@ final class Classifier
         }
 
         // Drop has highest priority (overrides client/unclear/spam/honeypot)
-        $is_drop_by_rule  = self::evaluate_hard_drop($fields);
+        $drop_trigger     = self::compute_hard_drop_trigger($fields);
         $is_drop_by_score = isset($thresholds['drop']) && $score <= (int)$thresholds['drop'];
-        if ($is_drop_by_rule || $is_drop_by_score) {
+        if ($drop_trigger !== null || $is_drop_by_score) {
             $label = 'drop';
-            $reasons[] = ['sign' => '×', 'weight' => 0, 'text' => self::drop_reason_label($fields, $thresholds, $is_drop_by_rule)];
+            $reason_text = $drop_trigger ?? ('score ≤ ' . (int)$thresholds['drop']);
+            $reasons[] = ['sign' => '×', 'weight' => 0, 'text' => $reason_text];
         }
 
         return ['score' => $score, 'label' => $label, 'reasons' => $reasons];
     }
 
-    private static function drop_reason_label(array $fields, array $thresholds, bool $by_rule): string
-    {
-        if ($by_rule) {
-            $hits = [];
-            if (self::has_short_latin_name($fields)) $hits[] = 'короткое латинское имя';
-            if (self::count_placeholder_fields($fields) >= 3) $hits[] = '≥3 поля-плейсхолдера';
-            return 'hard-rule: ' . implode(' + ', $hits);
-        }
-        return 'score ≤ ' . (int)$thresholds['drop'];
-    }
-
     private static function concat_fields(array $fields): string
     {
         $out = [];
@@ -333,6 +323,40 @@ final class Classifier
         return $count;
     }
 
+    /**
+     * Returns the hard-rule trigger description, or null if no rule fires.
+     * Centralises positive-signal checks + trigger detection so callers don't
+     * recompute. Used by evaluate_hard_drop() and classify()'s reason builder.
+     *
+     * @param array<string,string|string[]> $fields CF7 posted_data
+     * @return string|null e.g. "hard-rule: короткое латинское имя + ≥3 поля-плейсхолдера"
+     */
+    private static function compute_hard_drop_trigger(array $fields): ?string
+    {
+        $rules = apply_filters('cf7stg_hard_drop_rules', self::DEFAULT_HARD_DROP_RULES);
+
+        // Positive-signal short-circuits
+        $name = self::pick_field($fields, ['your-name', 'name', 'имя', 'fio']);
+        if ($name === '') $name = FieldDetector::find_name($fields);
+        if ($name !== '' && self::is_cyrillic_name($name)) return null;
+
+        $message = self::pick_field($fields, ['your-message', 'message', 'comment', 'сообщение', 'вопрос']);
+        if ($message !== '' && self::is_meaningful_text($message)) return null;
+
+        if (self::has_valid_email_anywhere($fields)) return null;
+
+        // Triggers
+        $hits = [];
+        if (!empty($rules['short_latin_name']) && self::has_short_latin_name($fields)) {
+            $hits[] = 'короткое латинское имя';
+        }
+        if (!empty($rules['placeholder_fields']) && self::count_placeholder_fields($fields) >= 3) {
+            $hits[] = '≥3 поля-плейсхолдера';
+        }
+        if (empty($hits)) return null;
+        return 'hard-rule: ' . implode(' + ', $hits);
+    }
+
     /**
      * Hard-rule decision: returns true if the submission has zero positive signals
      * (no cyrillic name, no meaningful text, no valid email anywhere) AND at least
@@ -345,22 +369,6 @@ final class Classifier
      */
     public static function evaluate_hard_drop(array $fields): bool
     {
-        $rules = apply_filters('cf7stg_hard_drop_rules', self::DEFAULT_HARD_DROP_RULES);
+        return self::compute_hard_drop_trigger($fields) !== null;
-
-        // Любой позитивный сигнал — НЕ drop
-        $name = self::pick_field($fields, ['your-name', 'name', 'имя', 'fio']);
-        if ($name === '') $name = FieldDetector::find_name($fields);
-        if ($name !== '' && self::is_cyrillic_name($name)) return false;
-
-        $message = self::pick_field($fields, ['your-message', 'message', 'comment', 'сообщение', 'вопрос']);
-        if ($message !== '' && self::is_meaningful_text($message)) return false;
-
-        if (self::has_valid_email_anywhere($fields)) return false;
-
-        // Триггеры
-        if (!empty($rules['short_latin_name']) && self::has_short_latin_name($fields)) return true;
-        if (!empty($rules['placeholder_fields']) && self::count_placeholder_fields($fields) >= 3) return true;
-
-        return false;
     }
 }

includes/class-message-formatter.php

@@ -108,6 +108,12 @@ final class MessageFormatter
         if (!$reasons) return '—';
         $parts = [];
         foreach ($reasons as $r) {
+            // Drop reasons use sign='×' weight=0 as a sentinel — render text only
+            // to avoid the meaningless "×0 hard-rule: ..." prefix.
+            if (($r['sign'] ?? '') === '×' && (int)($r['weight'] ?? 0) === 0) {
+                $parts[] = (string)$r['text'];
+                continue;
+            }
             $parts[] = $r['sign'] . $r['weight'] . ' ' . $r['text'];
         }
         return esc_html(implode(', ', $parts));

tests/ClassifierTest.php

@@ -20,7 +20,7 @@ final class ClassifierTest extends Cf7stgTestCase
         self::assertGreaterThanOrEqual(3, $r['score']);
     }
 
-    public function test_seo_spam_with_url_is_red(): void
+    public function test_seo_spam_with_url_yields_drop(): void
     {
         // score = SEO(-2) + URL(-3) + latin_only(-1) = -6, which is ≤ drop threshold(-5)
         // → label promoted from spam to drop (score-based drop, no hard-rule since email is valid)