From f8748af154f80c23a32e851317463129aeb45e2f Mon Sep 17 00:00:00 2001
From: Ghlen Nagels <ghlen@pm.me>
Date: Mon, 11 Dec 2023 17:22:57 +0530
Subject: [PATCH] tested edge cases

fixes #193
---
 src/Types/AbstractCypherSequence.php | 19 ++++++++-------
 src/Types/ArrayList.php              | 29 +++++++++-------------
 tests/Unit/CypherListTest.php        | 36 ++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 27 deletions(-)

diff --git a/src/Types/AbstractCypherSequence.php b/src/Types/AbstractCypherSequence.php
index 992b5489..f7271197 100644
--- a/src/Types/AbstractCypherSequence.php
+++ b/src/Types/AbstractCypherSequence.php
@@ -446,15 +446,16 @@ public function current(): mixed
 
     public function valid(): bool
     {
-        return $this->currentPosition < $this->generatorPosition || $this->getGenerator()->valid();
+        return $this->currentPosition < $this->generatorPosition || array_key_exists($this->currentPosition, $this->keyCache) || $this->getGenerator()->valid();
     }
 
     public function rewind(): void
     {
-        $this->currentPosition = max(
-            $this->currentPosition - $this->cacheLimit - 1,
-            0
-        );
+        if ($this->currentPosition > $this->cacheLimit) {
+            throw new BadMethodCallException('Cannot rewind cursor: limit exceeded. In order to increase the amount of prefetched (and consequently cached) rows, increase the fetch limit in the session configuration.');
+        }
+
+        $this->currentPosition = 0;
     }
 
     public function next(): void
@@ -489,7 +490,7 @@ public function key(): mixed
      */
     protected function cacheKey()
     {
-        return $this->keyCache[$this->currentPosition % max($this->cacheLimit - 1, 1)];
+        return $this->keyCache[$this->currentPosition % max($this->cacheLimit, 1)];
     }
 
     /**
@@ -519,9 +520,9 @@ private function setupCache(): void
     {
         $generator = $this->getGenerator();
 
-        if (count($this->cache) % $this->cacheLimit === 0) {
-            $this->cache = [];
-            $this->keyCache = [];
+        if (count($this->cache) !== 0 && count($this->cache) % ($this->cacheLimit + 1) === 0) {
+            $this->cache = [array_key_last($this->cache) => $this->cache[array_key_last($this->cache)]];
+            $this->keyCache = [$this->keyCache[array_key_last($this->keyCache)]];
         }
 
         if ($this->cache === [] && $generator->valid()) {
diff --git a/src/Types/ArrayList.php b/src/Types/ArrayList.php
index 9ea75ed6..0738fa55 100644
--- a/src/Types/ArrayList.php
+++ b/src/Types/ArrayList.php
@@ -14,9 +14,6 @@
 namespace Laudis\Neo4j\Types;
 
 use AppendIterator;
-
-use function array_values;
-
 use ArrayIterator;
 use Generator;
 
@@ -45,22 +42,18 @@ class ArrayList extends AbstractCypherSequence
     public function __construct($iterable = [])
     {
         if (is_array($iterable)) {
-            /** @var array<array-key, TValue> $iterable */
-            $this->keyCache = count($iterable) === 0 ? [] : range(0, count($iterable) - 1);
-            $this->cache = array_values($iterable);
-            $this->generator = new ArrayIterator([]);
-            $this->generatorPosition = count($this->keyCache);
-        } else {
-            $this->generator = static function () use ($iterable): Generator {
-                $i = 0;
-                /** @var Generator<mixed, TValue> $it */
-                $it = is_callable($iterable) ? $iterable() : $iterable;
-                foreach ($it as $value) {
-                    yield $i => $value;
-                    ++$i;
-                }
-            };
+            $iterable = new ArrayIterator($iterable);
         }
+
+        $this->generator = static function () use ($iterable): Generator {
+            $i = 0;
+            /** @var Generator<mixed, TValue> $it */
+            $it = is_callable($iterable) ? $iterable() : $iterable;
+            foreach ($it as $value) {
+                yield $i => $value;
+                ++$i;
+            }
+        };
     }
 
     /**
diff --git a/tests/Unit/CypherListTest.php b/tests/Unit/CypherListTest.php
index 2ecd17cf..d10fc496 100644
--- a/tests/Unit/CypherListTest.php
+++ b/tests/Unit/CypherListTest.php
@@ -459,6 +459,42 @@ public function testSlice(): void
         self::assertEquals(array_sum(range(5, 7)), $sumAfter);
     }
 
+    public function testRewindValid(): void
+    {
+        $list = $this->list->withCacheLimit(4);
+
+        $x = iterator_to_array($list);
+        $y = iterator_to_array($list);
+
+        $this->assertEquals(['A', 'B', 'C'], $x);
+        $this->assertEquals(['A', 'B', 'C'], $y);
+    }
+
+    public function testRewindValidExact(): void
+    {
+        $list = $this->list->withCacheLimit(3);
+
+        $x = iterator_to_array($list);
+        $y = iterator_to_array($list);
+
+        $this->assertEquals(['A', 'B', 'C'], $x);
+        $this->assertEquals(['A', 'B', 'C'], $y);
+    }
+
+    public function testRewindInValid(): void
+    {
+        $list = $this->list->withCacheLimit(2);
+
+        $x = iterator_to_array($list);
+
+        $this->assertEquals(['A', 'B', 'C'], $x);
+
+        $this->expectException(BadMethodCallException::class);
+        $this->expectExceptionMessage('Cannot rewind cursor: limit exceeded. In order to increase the amount of prefetched (and consequently cached) rows, increase the fetch limit in the session configuration.');
+
+        iterator_to_array($list);
+    }
+
     /**
      * @return Generator<int, int>
      */