From 40f5f77be0fe78127f3d4e76a6678af3a03a4213 Mon Sep 17 00:00:00 2001
From: Stefan Zerkalica <zerkalica@gmail.com>
Date: Mon, 18 Sep 2023 00:20:31 +0300
Subject: [PATCH] $mol_slicer: temp window

---
 slicer/slicer.test.ts | 27 +++++++++++++++++++--------
 slicer/slicer.ts      | 30 ++++++++++++++++--------------
 2 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/slicer/slicer.test.ts b/slicer/slicer.test.ts
index 4d262c8f7c9..3c781a2997d 100644
--- a/slicer/slicer.test.ts
+++ b/slicer/slicer.test.ts
@@ -38,22 +38,33 @@ namespace $ {
 
 		'multiple push'($) {
 			const { range, stub } = make_range()
+
 			const arr = range.range()
 
+			let calls = 0
+			const fresh_stub = stub_ids(10)
+			range.chunk = () => {
+				calls++
+				return fresh_stub
+			}
 			const appended = stub_ids(30)
 			range.temp_push(...appended)
 
 			$mol_assert_equal(arr.length, appended.length + stub.length)
+			$mol_assert_equal(arr[29], appended[4])
+			$mol_assert_equal(arr[30], appended[5])
+			range.temp_cut()
+			$mol_assert_equal(arr.length, appended.length + stub.length)
+			$mol_assert_equal(arr[29], appended[4])
+			$mol_assert_equal(arr[30], fresh_stub[0])
+			$mol_assert_equal(calls, 1)
 
-			let calls = 0
-			range.chunk = offset => {
-				calls++
-				return []
-			}
-
-			arr[50]
+			const appended2 = stub_ids(30)
+			range.temp_push(...appended2)
+			$mol_assert_equal(arr[60], appended2[5])
+			range.temp_cut()
+			$mol_assert_equal(arr[60], fresh_stub[0])
 
-			$mol_assert_equal(calls, 0)
 		},
 	})
 }
diff --git a/slicer/slicer.ts b/slicer/slicer.ts
index de637f9563c..0357a616fad 100644
--- a/slicer/slicer.ts
+++ b/slicer/slicer.ts
@@ -28,14 +28,16 @@ namespace $ {
 			return id
 		}
 
+		protected temp = [] as Item[]
+
 		@ $mol_mem
-		temp(next?: readonly Item[]) {
-			return next ?? []
+		temp_len(next?: number) {
+			return next ?? 0
 		}
 
 		temp_push(...ids: readonly Item[]) {
-			this.temp([ ...this.temp(), ...ids ])
-			this.temp_cut()
+			this.temp.push(...ids)
+			this.temp_len(this.temp.length)
 
 			return this.length
 		}
@@ -45,30 +47,30 @@ namespace $ {
 		}
 
 		temp_cut() {
-			const temp = this.temp()
-			if (! temp) return
+			if (! this.temp.length) return
 
 			const limit = this.chunk_size()
 			const addenum = this.count() % limit
-			const delete_chunks = Math.ceil((temp.length - addenum) / limit) - this.temp_chunk_min()
+			const delete_chunks = Math.ceil((this.temp.length - addenum) / limit) - this.temp_chunk_min()
 			if (delete_chunks <= 0) return
 
 			const delete_count = delete_chunks * limit
-			const next = temp.slice()
-			next.splice(addenum, delete_count)
-			this.temp(next)
+			this.temp.splice(addenum, delete_count)
 			this.removed_count += delete_count
+			this.temp_len(this.temp.length)
 		}
 
 		at(index: number) {
 			if (index < 0) index = Math.max(0, this.length + index)
 			const count = this.count()
 			const addenum = count % this.chunk_size()
-			const temp = this.temp()
+			const temp_len = this.temp_len()
 
 			let temp_index = index - count
-			if (temp_index > addenum) temp_index -= this.removed_count
-			if (temp_index >= 0 && temp_index < temp.length) return temp[temp_index]
+
+			if (temp_index >= 0 && temp_index < temp_len && temp_index < addenum) return this.temp[temp_index]
+			temp_index -= this.removed_count
+			if (temp_index >= 0 && temp_index < temp_len) return this.temp[temp_index]
 
 			return this.item(index)
 		}
@@ -76,7 +78,7 @@ namespace $ {
 		protected removed_count = 0
 
 		get length() {
-			return this.count() + this.removed_count + this.temp().length
+			return this.count() + this.removed_count + this.temp_len()
 		}
 
 		@ $mol_mem