From 27549e9eff28f765facd9954d472788ae86cecfe Mon Sep 17 00:00:00 2001
From: rgazelot <r.gazelot@gmail.com>
Date: Wed, 16 Jul 2014 18:13:48 +0200
Subject: [PATCH] Compare a diff by identifier

---
 src/AbstractSnapshot.php |  5 +++--
 src/Set.php              | 38 +++++++++++++++++++++++++++++++++++++-
 src/SetInterface.php     |  3 ++-
 test/SetTest.php         | 26 +++++++++++++++++++++++++-
 4 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/src/AbstractSnapshot.php b/src/AbstractSnapshot.php
index 64414f1..c7102a3 100644
--- a/src/AbstractSnapshot.php
+++ b/src/AbstractSnapshot.php
@@ -52,18 +52,19 @@ public function setSetClass($class)
      * Calculate the diff between two snapshots
      *
      * @param AbstractSnapshot $snapshot Snapshot to compare this one to
+     * @param mixed            $id       Compare the old and new entries by a given key
      *
      * @return Set Changeset between the two snapshots
      * @throws IncomparableDataException If the two snapshots are not comparable
      */
-    public function diff(AbstractSnapshot $snapshot)
+    public function diff(AbstractSnapshot $snapshot, $id = null)
     {
         if (!$this->isComparable($snapshot)) {
             throw new IncomparableDataException;
         }
 
         $set = new $this->setClass;
-        $set->compute($this, $snapshot);
+        $set->compute($this, $snapshot, $id);
 
         return $set;
     }
diff --git a/src/Set.php b/src/Set.php
index e6f5b39..e10bdae 100644
--- a/src/Set.php
+++ b/src/Set.php
@@ -134,7 +134,7 @@ public function getIterator()
     }
 
     /** {@inheritDoc} */
-    public function compute(AbstractSnapshot $old, AbstractSnapshot $new)
+    public function compute(AbstractSnapshot $old, AbstractSnapshot $new, $id = null)
     {
         if (null !== $this->changes) {
             return;
@@ -142,6 +142,12 @@ public function compute(AbstractSnapshot $old, AbstractSnapshot $new)
 
         $this->changes = [];
 
+        if (null !== $id) {
+            $this->computeEntryById($old, $new, $id);
+
+            return;
+        }
+
         foreach (array_replace($old->getDataKeys(), $new->getDataKeys()) as $key) {
             $result = $this->computeEntry($old, $new, $key);
 
@@ -151,6 +157,36 @@ public function compute(AbstractSnapshot $old, AbstractSnapshot $new)
         }
     }
 
+    /**
+     * Compare old and new snapshot by a given id
+     *
+     * @param   AbstractSnapshot  $old
+     * @param   AbstractSnapshot  $new
+     * @param   mixed             $id
+     */
+    private function computeEntryById(AbstractSnapshot $old, AbstractSnapshot $new, $id)
+    {
+        foreach ($old->getRawData() as $oldArray) {
+            foreach ($new->getRawData() as $newArray) {
+                if ($oldArray[$id] === $newArray[$id]) {
+                    continue 2;
+                }
+            }
+
+            $this->changes[] = new Removal($oldArray);
+        }
+
+        foreach ($new->getRawData() as $newArray) {
+            foreach ($new->getRawData() as $oldArray) {
+                if ($oldArray[$id] === $newArray[$id]) {
+                    continue 2;
+                }
+            }
+
+            $this->changes[] = new Addition($newArray);
+        }
+    }
+
     /**
      * Calculate the difference between two snapshots for a given key
      *
diff --git a/src/SetInterface.php b/src/SetInterface.php
index 19c21fe..00100f2 100644
--- a/src/SetInterface.php
+++ b/src/SetInterface.php
@@ -48,7 +48,8 @@ public function hasChanged($property);
      *
      * @param AbstractSnapshot $old Old snapshot
      * @param AbstractSnapshot $new New snapshot
+     * @param mixed            $id  Compare the old and new entries by a given key
      */
-    public function compute(AbstractSnapshot $old, AbstractSnapshot $new);
+    public function compute(AbstractSnapshot $old, AbstractSnapshot $new, $id = null);
 }
 
diff --git a/test/SetTest.php b/test/SetTest.php
index fa46cb9..307bca3 100644
--- a/test/SetTest.php
+++ b/test/SetTest.php
@@ -16,6 +16,7 @@
 use \PHPUnit_Framework_TestCase;
 
 use Totem\Set,
+    Totem\AbstractSnapshot,
     Totem\Snapshot\ArraySnapshot,
     Totem\Snapshot\ObjectSnapshot;
 
@@ -181,5 +182,28 @@ public function testAlreadyComputedSetShouldNotRecompute()
 
         $set->compute($old, $new);
     }
-}
 
+    public function testComputeWithById()
+    {
+        $old = new ArraySnapshot([
+            ['hash' => 'aaa', 'name' => 'foo'],
+            ['hash' => 'bbb', 'name' => 'bar'],
+            ['hash' => 'ccc', 'name' => 'baz'],
+        ]);
+        $new = new ArraySnapshot([
+            ['hash' => 'aaa', 'name' => 'foo'],
+            ['hash' => 'ccc', 'name' => 'baz'],
+        ]);
+
+        $set = new Set;
+        $set->compute($old, $new, 'hash');
+
+        $this->assertEquals(1, $set->count());
+
+        foreach ($set as $change) {
+            $this->assertInstanceOf('Totem\\Change\\Removal', $change);
+            $this->assertEquals('bbb', $change->getOld()['hash']);
+            $this->assertNull($change->getNew());
+        }
+    }
+}