From 8bf39d58de34fcab8d612fd122c234681f43d6f3 Mon Sep 17 00:00:00 2001
From: Ben Adrian Sarmiento <me@bensarmiento.com>
Date: Fri, 21 Jun 2024 12:34:14 +0200
Subject: [PATCH] Proper cached index computation

---
 pkg/realdebrid/torrents.go | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/pkg/realdebrid/torrents.go b/pkg/realdebrid/torrents.go
index c31f836..d10c63f 100644
--- a/pkg/realdebrid/torrents.go
+++ b/pkg/realdebrid/torrents.go
@@ -23,21 +23,23 @@ func (rd *RealDebrid) GetTorrents(onlyOne bool) ([]Torrent, int, error) {
 		return nil, 0, result.err
 	}
 
+	totalElements := result.total
+
 	if onlyOne {
-		return result.torrents, result.total, nil
+		return result.torrents, totalElements, nil
 	}
 
 	allTorrents := []Torrent{}
 	page := 1
 	pageSize := 250
 
-	maxPages := (result.total + pageSize - 1) / pageSize
-	rd.log.Debugf("Torrents total count is %d", result.total)
+	maxPages := (totalElements + pageSize - 1) / pageSize
+	rd.log.Debugf("Torrents total count is %d", totalElements)
 	maxParallelThreads := 4
 	if maxPages < maxParallelThreads {
 		maxParallelThreads = maxPages
 	}
-	found := false
+	found := -1
 	for {
 		allResults := make(chan fetchTorrentsResult, maxParallelThreads) // Channel to collect results from goroutines
 		for i := 0; i < maxParallelThreads; i++ {                        // Launch GET_PARALLEL concurrent fetches
@@ -47,7 +49,7 @@ func (rd *RealDebrid) GetTorrents(onlyOne bool) ([]Torrent, int, error) {
 					allResults <- fetchTorrentsResult{
 						torrents: nil,
 						page:     page + idx,
-						total:    result.total,
+						total:    totalElements,
 						err:      nil,
 					}
 					return
@@ -67,32 +69,37 @@ func (rd *RealDebrid) GetTorrents(onlyOne bool) ([]Torrent, int, error) {
 			batches[bIdx] = append(batches[bIdx], result.torrents...)
 		}
 		for bIdx, batch := range batches { // 4 batches
-			if !found && len(batch) > 0 {
+			if found < 0 && len(batch) > 0 {
 				cachedCount := len(rd.torrentsCache)
 				for cIdx, cached := range rd.torrentsCache { // N cached torrents
 					cIdxEnd := cachedCount - 1 - cIdx
 					for tIdx, torrent := range batch { // 250 torrents in batch
-						tIdxEnd := indexFromEnd(tIdx, page+bIdx, pageSize, result.total)
+						tIdxEnd := indexFromEnd(tIdx, page+bIdx, pageSize, totalElements)
 						if torrent.ID == cached.ID && torrent.Progress == cached.Progress && tIdxEnd == cIdxEnd {
-							found = true
+							found = ((page + bIdx - 1) * pageSize) + tIdx
 							break
 						}
 					}
-					if found {
-						// rd.log.Debugf("From torrent %s (id=%s) onwards, the torrents were untouched", cached.Name, cached.ID)
+					if found >= 0 {
 						break
 					}
 				}
 			}
 			allTorrents = append(allTorrents, batch...)
 		}
-		if found {
-			allTorrents = append(allTorrents, rd.torrentsCache[len(allTorrents):]...)
+		if found >= 0 {
+			tIdx := found % pageSize
+			pageNum := (found / pageSize) + 1
+			tIdxEnd := indexFromEnd(tIdx, pageNum, pageSize, totalElements)
+			cIdx := len(rd.torrentsCache) - 1 - tIdxEnd
+			last := len(allTorrents) - 1
+			cIdx += last - found + 1
+			allTorrents = append(allTorrents, rd.torrentsCache[cIdx:]...)
 		}
 
-		rd.log.Debugf("Got %d/%d torrents", len(allTorrents), result.total)
+		rd.log.Debugf("Got %d/%d torrents", len(allTorrents), totalElements)
 
-		if len(allTorrents) >= result.total || page >= maxPages {
+		if len(allTorrents) >= totalElements || page >= maxPages {
 			break
 		}