From 595503cfc35c8db3cb4ee4b28f82b7c91ee75dff Mon Sep 17 00:00:00 2001
From: Pieter Vander Vennet <pietervdvn@posteo.net>
Date: Thu, 30 Nov 2023 00:30:46 +0100
Subject: [PATCH] Fix: improve optimization; add tests

---
 src/Logic/Tags/And.ts      | 32 ++++++++++++++++++++++++++------
 src/Logic/Tags/Or.ts       | 15 +++++++++++++--
 src/Logic/Tags/TagUtils.ts |  8 ++++++++
 3 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/src/Logic/Tags/And.ts b/src/Logic/Tags/And.ts
index 98da75ae0..dff0919f8 100644
--- a/src/Logic/Tags/And.ts
+++ b/src/Logic/Tags/And.ts
@@ -233,6 +233,15 @@ export class And extends TagsFilter {
         return And.construct(newAnds)
     }
 
+    /**
+     * const raw = {"and": [{"or":["leisure=playground","playground!=forest"]},{"or":["leisure=playground","playground!=forest"]}]}
+     * const parsed = TagUtils.Tag(raw)
+     * parsed.optimize().asJson() // => {"or":["leisure=playground","playground!=forest"]}
+     *
+     * const raw = {"and": [{"and":["advertising=screen"]}, {"and":["advertising~*"]}]}]
+     * const parsed = TagUtils.Tag(raw)
+     * parsed.optimize().asJson() // => "advertising=screen"
+     */
     optimize(): TagsFilter | boolean {
         if (this.and.length === 0) {
             return true
@@ -294,9 +303,17 @@ export class And extends TagsFilter {
                             optimized.splice(i, 1)
                             i--
                         }
-                    } else if (v !== opt.value) {
-                        // detected an internal conflict
-                        return false
+                    } else {
+                        if (!v.match(opt.value)) {
+                            // We _know_ that for the key of the RegexTag `opt`, the value will be `v`.
+                            // As such, if `opt.value` cannot match `v`, we detected an internal conflict and can fail
+
+                            return false
+                        } else {
+                            // Another tag already provided a _stricter_ value then this regex, so we can remove this one!
+                            optimized.splice(i, 1)
+                            i--
+                        }
                     }
                 }
             }
@@ -374,10 +391,13 @@ export class And extends TagsFilter {
                     const elements = containedOr.or.filter(
                         (candidate) => !commonValues.some((cv) => cv.shadows(candidate))
                     )
-                    newOrs.push(Or.construct(elements))
+                    if (elements.length > 0) {
+                        newOrs.push(Or.construct(elements))
+                    }
+                }
+                if (newOrs.length > 0) {
+                    commonValues.push(And.construct(newOrs))
                 }
-
-                commonValues.push(And.construct(newOrs))
                 const result = new Or(commonValues).optimize()
                 if (result === false) {
                     return false
diff --git a/src/Logic/Tags/Or.ts b/src/Logic/Tags/Or.ts
index da932049a..a0c0f6622 100644
--- a/src/Logic/Tags/Or.ts
+++ b/src/Logic/Tags/Or.ts
@@ -162,6 +162,12 @@ export class Or extends TagsFilter {
         return Or.construct(newOrs)
     }
 
+    /**
+     * const raw = {"or": [{"and":["leisure=playground","playground!=forest"]},{"and":["leisure=playground","playground!=forest"]}]}
+     * const parsed = TagUtils.Tag(raw)
+     * parsed.optimize().asJson() // => {"and":["leisure=playground","playground!=forest"]}
+     *
+     */
     optimize(): TagsFilter | boolean {
         if (this.or.length === 0) {
             return false
@@ -241,16 +247,21 @@ export class Or extends TagsFilter {
                     const elements = containedAnd.and.filter(
                         (candidate) => !commonValues.some((cv) => cv.shadows(candidate))
                     )
+                    if (elements.length == 0) {
+                        continue
+                    }
                     newAnds.push(And.construct(elements))
                 }
+                if (newAnds.length > 0) {
+                    commonValues.push(Or.construct(newAnds))
+                }
 
-                commonValues.push(Or.construct(newAnds))
                 const result = new And(commonValues).optimize()
                 if (result === true) {
                     return true
                 } else if (result === false) {
                     // neutral element: skip
-                } else {
+                } else if (commonValues.length > 0) {
                     newOrs.push(And.construct(commonValues))
                 }
             }
diff --git a/src/Logic/Tags/TagUtils.ts b/src/Logic/Tags/TagUtils.ts
index 91d3a4ca6..0a8de68d6 100644
--- a/src/Logic/Tags/TagUtils.ts
+++ b/src/Logic/Tags/TagUtils.ts
@@ -325,6 +325,14 @@ export class TagUtils {
         return tags
     }
 
+    static optimzeJson(json: TagConfigJson): TagConfigJson | boolean {
+        const optimized = TagUtils.Tag(json).optimize()
+        if (optimized === true || optimized === false) {
+            return optimized
+        }
+        return optimized.asJson()
+    }
+
     /**
      * Given multiple tagsfilters which can be used as answer, will take the tags with the same keys together as set.
      *