From 19dba8409070b4b0d5a2c09a6a1750f1adc8d5e9 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@icinga.com>
Date: Mon, 18 Mar 2024 17:06:13 +0100
Subject: [PATCH 1/4] Rule: Require `sameAs(Rule $rule): bool` from
 implementors

---
 src/Filter/Rule.php | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/Filter/Rule.php b/src/Filter/Rule.php
index dc83c80..60b215b 100644
--- a/src/Filter/Rule.php
+++ b/src/Filter/Rule.php
@@ -4,4 +4,12 @@
 
 interface Rule
 {
+    /**
+     * Get whether the given rule is semantically the same as this one
+     *
+     * @param Rule $rule
+     *
+     * @return bool
+     */
+    public function sameAs(Rule $rule): bool;
 }

From e48a27375e9b8aedbbe4e6187c7a510a24b62a05 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@icinga.com>
Date: Mon, 18 Mar 2024 17:07:15 +0100
Subject: [PATCH 2/4] Filter\Condition: Implement `sameAs(Rule $rule): bool`

---
 src/Filter/Condition.php | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/Filter/Condition.php b/src/Filter/Condition.php
index cc35610..b42b6c3 100644
--- a/src/Filter/Condition.php
+++ b/src/Filter/Condition.php
@@ -34,6 +34,13 @@ public function __clone()
         }
     }
 
+    public function sameAs(Rule $rule): bool
+    {
+        return $rule instanceof static
+            && $rule->getColumn() === $this->getColumn()
+            && $rule->getValue() === $this->getValue();
+    }
+
     /**
      * Set this condition's column
      *

From e15a8cf331c30db3f7ffbdd66fb68b1355de9483 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@icinga.com>
Date: Mon, 18 Mar 2024 17:07:40 +0100
Subject: [PATCH 3/4] Filter\Chain: Implement `sameAs(Rule $rule): bool`

---
 src/Filter/Chain.php | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/Filter/Chain.php b/src/Filter/Chain.php
index c0060e6..911f5f1 100644
--- a/src/Filter/Chain.php
+++ b/src/Filter/Chain.php
@@ -42,6 +42,35 @@ public function __clone()
         }
     }
 
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if (count($rule) !== count($this->rules)) {
+            return false;
+        }
+
+        $theirRules = iterator_to_array($rule);
+        foreach ($this->rules as $myRule) {
+            $found = false;
+            foreach ($theirRules as $i => $theirRule) {
+                if ($myRule->sameAs($theirRule)) {
+                    unset($theirRules[$i]);
+                    $found = true;
+                    break;
+                }
+            }
+
+            if (! $found) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     /**
      * Get an iterator this chain's rules
      *

From 5d59f952fca4e9e52f1f122ba54c511b71432de4 Mon Sep 17 00:00:00 2001
From: Johannes Meyer <johannes.meyer@icinga.com>
Date: Mon, 18 Mar 2024 17:08:06 +0100
Subject: [PATCH 4/4] Consider special cases when comparing filter rules

---
 src/Filter/Equal.php   | 17 +++++++++++++++++
 src/Filter/Like.php    | 17 +++++++++++++++++
 src/Filter/Unequal.php | 17 +++++++++++++++++
 src/Filter/Unlike.php  | 17 +++++++++++++++++
 4 files changed, 68 insertions(+)

diff --git a/src/Filter/Equal.php b/src/Filter/Equal.php
index 71da490..f1ed137 100644
--- a/src/Filter/Equal.php
+++ b/src/Filter/Equal.php
@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($this->ignoresCase() !== $rule->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }
diff --git a/src/Filter/Like.php b/src/Filter/Like.php
index 7a06279..9336921 100644
--- a/src/Filter/Like.php
+++ b/src/Filter/Like.php
@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($rule->ignoresCase() !== $this->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }
diff --git a/src/Filter/Unequal.php b/src/Filter/Unequal.php
index 5e37cbd..e231b8b 100644
--- a/src/Filter/Unequal.php
+++ b/src/Filter/Unequal.php
@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($this->ignoresCase() !== $rule->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }
diff --git a/src/Filter/Unlike.php b/src/Filter/Unlike.php
index 16b9fb3..1737ed6 100644
--- a/src/Filter/Unlike.php
+++ b/src/Filter/Unlike.php
@@ -28,4 +28,21 @@ public function ignoresCase()
     {
         return $this->ignoreCase;
     }
+
+    public function sameAs(Rule $rule): bool
+    {
+        if (! $rule instanceof static) {
+            return false;
+        }
+
+        if ($rule->ignoresCase() !== $this->ignoresCase()) {
+            return false;
+        }
+
+        if (is_array($this->value)) {
+            return array_diff($this->value, (array) $rule->getValue()) === [];
+        }
+
+        return parent::sameAs($rule);
+    }
 }