feat: support action expression parsing, validation, and evaluation

app/TransactionRules/Expressions/ActionExpressionEvaluator.php

@@ -0,0 +1,95 @@
+<?php
+
+/**
+ * ActionExpressionEvaluator.php
+ * Copyright (c) 2024 Michael Thomas
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace FireflyIII\TransactionRules\Expressions;
+
+use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
+use Symfony\Component\ExpressionLanguage\SyntaxError;
+
+class ActionExpressionEvaluator
+{
+    private static array $NAMES = array("transaction");
+
+    private string $expr;
+    private bool $isExpression;
+    private ExpressionLanguage $expressionLanguage;
+
+    public function __construct(ExpressionLanguage $expressionLanguage, string $expr)
+    {
+        $this->expressionLanguage = $expressionLanguage;
+        $this->expr = $expr;
+
+        $this->isExpression = self::isExpression($expr);
+    }
+
+    private static function isExpression(string $expr): bool
+    {
+        return str_starts_with($expr, "=");
+    }
+
+    public function isValid(): bool
+    {
+        if (!$this->isExpression) {
+            return true;
+        }
+
+        try {
+            $this->lint(array());
+            return true;
+        } catch (SyntaxError $e) {
+            return false;
+        }
+    }
+
+    private function lintExpression(string $expr): void
+    {
+        $this->expressionLanguage->lint($expr, self::$NAMES);
+    }
+
+    public function lint(): void
+    {
+        if (!$this->isExpression) {
+            return;
+        }
+
+        $this->lintExpression(substr($this->expr, 1));
+    }
+
+    private function evaluateExpression(string $expr, array $journal): string
+    {
+        $result = $this->expressionLanguage->evaluate($expr, [
+            "transaction" => $journal
+        ]);
+        return strval($result);
+    }
+
+    public function evaluate(array $journal): string
+    {
+        if (!$this->isExpression) {
+            return $this->expr;
+        }
+
+        return $this->evaluateExpression(substr($this->expr, 1), $journal);
+    }
+}

app/TransactionRules/Expressions/ActionExpressionLanguageProvider.php

@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * ActionExpressionLanguageProvider.php
+ * Copyright (c) 2024 Michael Thomas
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace FireflyIII\TransactionRules\Expressions;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+use Symfony\Component\ExpressionLanguage\ExpressionFunctionProviderInterface;
+
+class ActionExpressionLanguageProvider implements ExpressionFunctionProviderInterface
+{
+    public function getFunctions(): array
+    {
+        return [
+            ExpressionFunction::fromPhp("substr"),
+            ExpressionFunction::fromPhp("strlen")
+        ];
+    }
+}