From be514f1a4551f00b6272621e4289c99013477a55 Mon Sep 17 00:00:00 2001
From: Bnyro <bnyro@tutanota.com>
Date: Mon, 23 Jan 2023 18:21:51 +0100
Subject: [PATCH] Don't load the whole watch history at once

---
 .../ui/adapters/WatchHistoryAdapter.kt        | 15 ++++++---
 .../ui/fragments/WatchHistoryFragment.kt      | 31 ++++++++++++-------
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/app/src/main/java/com/github/libretube/ui/adapters/WatchHistoryAdapter.kt b/app/src/main/java/com/github/libretube/ui/adapters/WatchHistoryAdapter.kt
index 1a8930306..92336e22f 100644
--- a/app/src/main/java/com/github/libretube/ui/adapters/WatchHistoryAdapter.kt
+++ b/app/src/main/java/com/github/libretube/ui/adapters/WatchHistoryAdapter.kt
@@ -21,6 +21,10 @@ class WatchHistoryAdapter(
 ) :
     RecyclerView.Adapter<WatchHistoryViewHolder>() {
 
+    var visibleCount = minOf(10, watchHistory.size)
+
+    override fun getItemCount(): Int = visibleCount
+
     fun removeFromWatchHistory(position: Int) {
         val history = watchHistory[position]
         query {
@@ -31,6 +35,13 @@ class WatchHistoryAdapter(
         notifyItemRangeChanged(position, itemCount)
     }
 
+    fun showMoreItems() {
+        val oldSize = visibleCount
+        visibleCount += minOf(10, watchHistory.size - oldSize)
+        if (visibleCount == oldSize) return
+        notifyItemRangeInserted(oldSize, visibleCount)
+    }
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): WatchHistoryViewHolder {
         val layoutInflater = LayoutInflater.from(parent.context)
         val binding = VideoRowBinding.inflate(layoutInflater, parent, false)
@@ -71,8 +82,4 @@ class WatchHistoryAdapter(
             watchProgress.setWatchProgressLength(video.videoId, video.duration)
         }
     }
-
-    override fun getItemCount(): Int {
-        return watchHistory.size
-    }
 }
diff --git a/app/src/main/java/com/github/libretube/ui/fragments/WatchHistoryFragment.kt b/app/src/main/java/com/github/libretube/ui/fragments/WatchHistoryFragment.kt
index 8a3976bb3..1fc8395c0 100644
--- a/app/src/main/java/com/github/libretube/ui/fragments/WatchHistoryFragment.kt
+++ b/app/src/main/java/com/github/libretube/ui/fragments/WatchHistoryFragment.kt
@@ -1,6 +1,8 @@
 package com.github.libretube.ui.fragments
 
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -28,6 +30,7 @@ class WatchHistoryFragment : BaseFragment() {
     private lateinit var binding: FragmentWatchHistoryBinding
 
     private val playerViewModel: PlayerViewModel by activityViewModels()
+    private var isLoading = false
 
     override fun onCreateView(
         inflater: LayoutInflater,
@@ -49,7 +52,7 @@ class WatchHistoryFragment : BaseFragment() {
 
         val watchHistory = awaitQuery {
             Database.watchHistoryDao().getAll()
-        }
+        }.reversed()
 
         if (watchHistory.isEmpty()) return
 
@@ -96,16 +99,15 @@ class WatchHistoryFragment : BaseFragment() {
             )
         }
 
-        // reversed order
-        binding.watchHistoryRecView.layoutManager = LinearLayoutManager(requireContext()).apply {
-            reverseLayout = true
-            stackFromEnd = true
-        }
-
         val watchHistoryAdapter = WatchHistoryAdapter(
             watchHistory.toMutableList()
         )
 
+        binding.watchHistoryRecView.layoutManager = LinearLayoutManager(context)
+        binding.watchHistoryRecView.adapter = watchHistoryAdapter
+        binding.historyEmpty.visibility = View.GONE
+        binding.historyScrollView.visibility = View.VISIBLE
+
         val itemTouchCallback = object : ItemTouchHelper.SimpleCallback(
             0,
             ItemTouchHelper.LEFT
@@ -130,7 +132,7 @@ class WatchHistoryFragment : BaseFragment() {
         val itemTouchHelper = ItemTouchHelper(itemTouchCallback)
         itemTouchHelper.attachToRecyclerView(binding.watchHistoryRecView)
 
-        // observe changes
+        // observe changes to indicate if the history is empty
         watchHistoryAdapter.registerAdapterDataObserver(object :
             RecyclerView.AdapterDataObserver() {
             override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {
@@ -141,8 +143,15 @@ class WatchHistoryFragment : BaseFragment() {
             }
         })
 
-        binding.watchHistoryRecView.adapter = watchHistoryAdapter
-        binding.historyEmpty.visibility = View.GONE
-        binding.historyScrollView.visibility = View.VISIBLE
+        // add a listener for scroll end, delay needed to prevent loading new ones the first time
+        Handler(Looper.getMainLooper()).postDelayed({
+            binding.historyScrollView.viewTreeObserver.addOnScrollChangedListener {
+                if (!binding.historyScrollView.canScrollVertically(1) && !isLoading) {
+                    isLoading = true
+                    watchHistoryAdapter.showMoreItems()
+                    isLoading = false
+                }
+            }
+        }, 200)
     }
 }