From 845356245c7a875259bbac2858fdc95cf9e07ed8 Mon Sep 17 00:00:00 2001
From: Marcel Klehr <mklehr@gmx.net>
Date: Sun, 24 Nov 2024 12:08:09 +0100
Subject: [PATCH] enh(Scanner): Improve move matching

by introducing a folder similarity measure

Signed-off-by: Marcel Klehr <mklehr@gmx.net>
---
 src/lib/Scanner.ts | 12 ++++++++++--
 src/lib/Tree.ts    | 23 ++++++++++++++++++++---
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/lib/Scanner.ts b/src/lib/Scanner.ts
index 231c6ba685..d6ab810b46 100644
--- a/src/lib/Scanner.ts
+++ b/src/lib/Scanner.ts
@@ -187,7 +187,11 @@ export default class Scanner<L1 extends TItemLocation, L2 extends TItemLocation>
           // give the browser time to breathe
           await Promise.resolve()
           const removedItem = removeAction.payload
-          const oldItem = removedItem.findItemFilter(createdItem.type, item => this.mergeable(item, createdItem))
+          const oldItem = removedItem.findItemFilter(
+            createdItem.type,
+            item => this.mergeable(item, createdItem),
+            item => item.childrenSimilarity(createdItem)
+          )
           if (oldItem) {
             let oldIndex
             this.result.CREATE.retract(createAction)
@@ -215,7 +219,11 @@ export default class Scanner<L1 extends TItemLocation, L2 extends TItemLocation>
               await this.diffItem(oldItem, createdItem)
             }
           } else {
-            const newItem = createdItem.findItemFilter(removedItem.type, item => this.mergeable(removedItem, item))
+            const newItem = createdItem.findItemFilter(
+              removedItem.type,
+              item => this.mergeable(removedItem, item),
+              item => item.childrenSimilarity(createdItem)
+            )
             let index
             if (newItem) {
               this.result.REMOVE.retract(removeAction)
diff --git a/src/lib/Tree.ts b/src/lib/Tree.ts
index 1910142af8..de941e2e61 100644
--- a/src/lib/Tree.ts
+++ b/src/lib/Tree.ts
@@ -74,6 +74,10 @@ export class Bookmark<L extends TItemLocation> {
     return false
   }
 
+  childrenSimilarity<L2 extends TItemLocation>(otherItem: TItem<L2>): number {
+    return 0
+  }
+
   async hash():Promise<string> {
     if (!this.hashValue) {
       this.hashValue = await Crypto.sha256(
@@ -107,7 +111,7 @@ export class Bookmark<L extends TItemLocation> {
   }
 
   // TODO: Make this return the correct type based on the type param
-  findItemFilter(type:TItemType, fn:(Item)=>boolean):TItem<L>|null {
+  findItemFilter(type:TItemType, fn:(item:TItem<L>)=>boolean, prefer:(item: TItem<L>)=>number = () => 1):TItem<L>|null {
     if (type === ItemType.BOOKMARK && fn(this)) {
       return this
     }
@@ -185,11 +189,13 @@ export class Folder<L extends TItemLocation> {
   }
 
   // eslint-disable-next-line no-use-before-define
-  findItemFilter(type:TItemType, fn:(Item)=>boolean):TItem<L>|null {
+  findItemFilter(type:TItemType, fn:(Item)=>boolean, prefer:(Item)=>number = () => 1):TItem<L>|null {
     if (!this.index) {
       this.createIndex()
     }
-    return Object.values(this.index[type]).find(fn)
+    const candidates = Object.values(this.index[type]).filter(fn)
+    // return the preferred match based on a preference measure
+    return candidates.sort((a,b) => prefer(a) - prefer(b)).pop()
   }
 
   findFolder(id:string|number): Folder<L> {
@@ -256,6 +262,17 @@ export class Folder<L extends TItemLocation> {
     return false
   }
 
+  childrenSimilarity<L2 extends TItemLocation>(otherItem: TItem<L2>): number {
+    if (otherItem instanceof Folder) {
+      return this.children.reduce(
+        (count, item) =>
+          otherItem.children.filter(i => i.title === item.title).length > 0 ? count + 1 : count,
+        0
+      ) / Math.max(this.children.length, otherItem.children.length)
+    }
+    return 0
+  }
+
   async hash(preserveOrder = false): Promise<string> {
     if (this.hashValue && this.hashValue[String(preserveOrder)]) {
       return this.hashValue[String(preserveOrder)]