From bf32801917c9a0f19809518e93973163febcc61a Mon Sep 17 00:00:00 2001
From: adrinr <adria@budibase.com>
Date: Thu, 16 Mar 2023 09:59:10 +0100
Subject: [PATCH] Handle skip on execution

---
 packages/backend-core/src/db/lucene.ts | 34 ++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/packages/backend-core/src/db/lucene.ts b/packages/backend-core/src/db/lucene.ts
index 9614bd6df2..fee89fcd7e 100644
--- a/packages/backend-core/src/db/lucene.ts
+++ b/packages/backend-core/src/db/lucene.ts
@@ -56,6 +56,7 @@ export class QueryBuilder<T> {
   #version?: string
   #indexBuilder?: () => Promise<any>
   #noEscaping = false
+  #skip?: number
 
   constructor(dbName: string, index: string, base?: SearchFilters) {
     this.#dbName = dbName
@@ -138,6 +139,11 @@ export class QueryBuilder<T> {
     return this
   }
 
+  setSkip(skip: number | undefined) {
+    this.#skip = skip
+    return this
+  }
+
   excludeDocs() {
     this.#includeDocs = false
     return this
@@ -468,6 +474,34 @@ export class QueryBuilder<T> {
   }
 
   async run() {
+    if (this.#skip) {
+      await this.#skipPages(this.#skip)
+    }
+    return await this.#execute()
+  }
+
+  async #skipPages(skip: number) {
+    // Lucene does not support pagination.
+    // Handle pagination by finding the right bookmark
+    const prevIncludeDocs = this.#includeDocs
+    const prevLimit = this.#limit
+
+    this.excludeDocs()
+    const maxPageSize = 1000
+    let skipRemaining = skip
+    do {
+      const toSkip = Math.min(maxPageSize, skipRemaining)
+      this.setLimit(toSkip)
+      const { bookmark } = await this.#execute()
+      this.setBookmark(bookmark)
+      skipRemaining -= toSkip
+    } while (skipRemaining > 0)
+
+    this.#includeDocs = prevIncludeDocs
+    this.#limit = prevLimit
+  }
+
+  async #execute() {
     const { url, cookie } = getCouchInfo()
     const fullPath = `${url}/${this.#dbName}/_design/database/_search/${
       this.#index