music: make musicloader async

Make MusicLoader instantiation fully asynchronous. This implementation
changes a lot about Auxio. For one, the loading screen is now gone.
However, many parts of the app now run under the fact that MusicStore
might not be available. However, I don't think there will be too much bugs
from it. Some more changes will be made to improve this implementation.

app/src/main/java/org/oxycblt/auxio/MainFragment.kt

@@ -58,8 +58,6 @@ class MainFragment : Fragment() {
 
         // --- VIEWMODEL SETUP ---
 
-        playbackModel.setupPlayback(requireContext())
-
         // Change CompactPlaybackFragment's visibility here so that an animation occurs.
         binding.mainPlayback.isVisible = playbackModel.song.value != null
 

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -78,23 +78,28 @@ class DetailViewModel : ViewModel() {
 
     private var currentMenuContext: DisplayMode? = null
 
-    private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
     fun setGenre(id: Long, context: Context) {
         if (mCurGenre.value?.id == id) return
+
+        val musicStore = MusicStore.requireInstance()
         mCurGenre.value = musicStore.genres.find { it.id == id }
         refreshGenreData(context)
     }
 
     fun setArtist(id: Long, context: Context) {
         if (mCurArtist.value?.id == id) return
+
+        val musicStore = MusicStore.requireInstance()
         mCurArtist.value = musicStore.artists.find { it.id == id }
         refreshArtistData(context)
     }
 
     fun setAlbum(id: Long, context: Context) {
         if (mCurAlbum.value?.id == id) return
+
+        val musicStore = MusicStore.requireInstance()
         mCurAlbum.value = musicStore.albums.find { it.id == id }
         refreshAlbumData(context)
     }

app/src/main/java/org/oxycblt/auxio/home/HomeFragment.kt

@@ -18,12 +18,16 @@
 
 package org.oxycblt.auxio.home
 
+import android.Manifest
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup
+import android.widget.Button
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.coordinatorlayout.widget.CoordinatorLayout
+import androidx.core.content.res.ResourcesCompat
 import androidx.core.view.iterator
 import androidx.core.view.updatePadding
 import androidx.core.view.updatePaddingRelative
@@ -34,6 +38,7 @@ import androidx.recyclerview.widget.RecyclerView
 import androidx.viewpager2.adapter.FragmentStateAdapter
 import androidx.viewpager2.widget.ViewPager2
 import com.google.android.material.appbar.AppBarLayout
+import com.google.android.material.snackbar.Snackbar
 import com.google.android.material.tabs.TabLayoutMediator
 import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
@@ -46,6 +51,7 @@ import org.oxycblt.auxio.home.list.SongListFragment
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.DisplayMode
@@ -73,6 +79,13 @@ class HomeFragment : Fragment() {
         var bottomPadding = 0
         val sortItem: MenuItem
 
+        // Build the permission launcher here as you can only do it in onCreateView/onCreate
+        val permLauncher = registerForActivityResult(
+            ActivityResultContracts.RequestPermission()
+        ) {
+            homeModel.reloadMusic(requireContext())
+        }
+
         // --- UI SETUP ---
 
         binding.lifecycleOwner = viewLifecycleOwner
@@ -193,22 +206,96 @@ class HomeFragment : Fragment() {
             registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
                 override fun onPageSelected(position: Int) = homeModel.updateCurrentTab(position)
             })
+
+            TabLayoutMediator(binding.homeTabs, this) { tab, pos ->
+                tab.setText(homeModel.tabs[pos].string)
+            }.attach()
         }
 
         binding.homeFab.setOnClickListener {
             playbackModel.shuffleAll()
         }
 
-        TabLayoutMediator(binding.homeTabs, binding.homePager) { tab, pos ->
-            tab.setText(homeModel.tabs[pos].string)
-        }.attach()
-
         // --- VIEWMODEL SETUP ---
 
+        // Initialize music loading. Unlike MainFragment, we can not only do this here on startup
+        // but also show a SnackBar in a reasonable place in this fragment.
+        homeModel.loadMusic(requireContext())
+
         // There is no way a fast scrolling event can continue across a re-create. Reset it.
         homeModel.updateFastScrolling(false)
 
+        homeModel.loaderResponse.observe(viewLifecycleOwner) { response ->
+            // Handle the loader response.
+            when (response) {
+                is MusicStore.Response.Ok -> {
+                    logD("Received Ok")
+
+                    binding.homeFab.show()
+                    playbackModel.setupPlayback(requireContext())
+                }
+
+                is MusicStore.Response.Err -> {
+                    logD("Received Error")
+
+                    // We received an error. Hide the FAB and show a Snackbar with the error
+                    // message and a corresponding action
+                    binding.homeFab.hide()
+
+                    val errorRes = when (response.kind) {
+                        MusicStore.ErrorKind.NO_MUSIC -> R.string.err_no_music
+                        MusicStore.ErrorKind.NO_PERMS -> R.string.err_no_perms
+                        MusicStore.ErrorKind.FAILED -> R.string.err_load_failed
+                    }
+
+                    val snackbar = Snackbar.make(
+                        binding.root, getString(errorRes), Snackbar.LENGTH_INDEFINITE
+                    )
+
+                    snackbar.view.apply {
+                        // Change the font family to our semibold color
+                        findViewById<Button>(
+                            com.google.android.material.R.id.snackbar_action
+                        ).typeface = ResourcesCompat.getFont(requireContext(), R.font.inter_semibold)
+
+                        fitsSystemWindows = false
+
+                        // Prevent fitsSystemWindows margins from being applied to this view
+                        // [We already do it]
+                        setOnApplyWindowInsetsListener { v, insets -> insets }
+                    }
+
+                    when (response.kind) {
+                        MusicStore.ErrorKind.FAILED, MusicStore.ErrorKind.NO_MUSIC -> {
+                            snackbar.setAction(R.string.lbl_retry) {
+                                homeModel.reloadMusic(requireContext())
+                            }
+                        }
+
+                        MusicStore.ErrorKind.NO_PERMS -> {
+                            snackbar.setAction(R.string.lbl_grant) {
+                                permLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
+                            }
+                        }
+                    }
+
+                    snackbar.show()
+                }
+
+                // While loading or during an error, make sure we keep the shuffle fab hidden so
+                // that any kind of loading is impossible. PlaybackStateManager also relies on this
+                // invariant, so please don't change it.
+                null -> binding.homeFab.hide()
+            }
+        }
+
         homeModel.fastScrolling.observe(viewLifecycleOwner) { scrolling ->
+            // Make sure an update here doesn't mess up the FAB state when it comes to the
+            // loader response.
+            if (homeModel.loaderResponse.value !is MusicStore.Response.Ok) {
+                return@observe
+            }
+
             if (scrolling) {
                 binding.homeFab.hide()
             } else {

app/src/main/java/org/oxycblt/auxio/home/HomeViewModel.kt

@@ -18,9 +18,12 @@
 
 package org.oxycblt.auxio.home
 
+import android.content.Context
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.launch
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
@@ -36,13 +39,8 @@ import org.oxycblt.auxio.ui.SortMode
  * @author OxygenCobalt
  */
 class HomeViewModel : ViewModel(), SettingsManager.Callback {
-    private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
-    /** Internal getter for getting the visible library tabs */
-    private val visibleTabs: List<DisplayMode> get() = settingsManager.libTabs
-        .filterIsInstance<Tab.Visible>().map { it.mode }
-
     private val mSongs = MutableLiveData(listOf<Song>())
     val songs: LiveData<List<Song>> get() = mSongs
 
@@ -58,12 +56,13 @@ class HomeViewModel : ViewModel(), SettingsManager.Callback {
     var tabs: List<DisplayMode> = visibleTabs
         private set
 
+    /** Internal getter for getting the visible library tabs */
+    private val visibleTabs: List<DisplayMode> get() = settingsManager.libTabs
+        .filterIsInstance<Tab.Visible>().map { it.mode }
+
     private val mCurTab = MutableLiveData(tabs[0])
     val curTab: LiveData<DisplayMode> = mCurTab
 
-    private val mFastScrolling = MutableLiveData(false)
-    val fastScrolling: LiveData<Boolean> = mFastScrolling
-
     /**
      * Marker to recreate all library tabs, usually initiated by a settings change.
      * When this flag is set, all tabs (and their respective viewpager fragments) will be
@@ -72,13 +71,51 @@ class HomeViewModel : ViewModel(), SettingsManager.Callback {
     private val mRecreateTabs = MutableLiveData(false)
     val recreateTabs: LiveData<Boolean> = mRecreateTabs
 
+    private val mFastScrolling = MutableLiveData(false)
+    val fastScrolling: LiveData<Boolean> = mFastScrolling
+
+    private val mLoaderResponse = MutableLiveData<MusicStore.Response?>(null)
+    val loaderResponse: LiveData<MusicStore.Response?> = mLoaderResponse
+
+    private var isBusy = false
+
     init {
+        settingsManager.addCallback(this)
+    }
+
+    /**
+     * Initiate the loading process. This is done here since HomeFragment will be the first
+     * fragment navigated to and because SnackBars will have the best UX here.
+     */
+    fun loadMusic(context: Context) {
+        if (mLoaderResponse.value != null || isBusy) {
+            return
+        }
+
+        isBusy = true
+        mLoaderResponse.value = null
+
+        viewModelScope.launch {
+            val result = MusicStore.initInstance(context)
+
+            isBusy = false
+            mLoaderResponse.value = result
+
+            if (result is MusicStore.Response.Ok) {
+                val musicStore = result.musicStore
+
                 mSongs.value = settingsManager.libSongSort.sortSongs(musicStore.songs)
                 mAlbums.value = settingsManager.libAlbumSort.sortAlbums(musicStore.albums)
                 mArtists.value = settingsManager.libArtistSort.sortModels(musicStore.artists)
                 mGenres.value = settingsManager.libGenreSort.sortModels(musicStore.genres)
+            }
+        }
+    }
 
-        settingsManager.addCallback(this)
+    fun reloadMusic(context: Context) {
+        mLoaderResponse.value = null
+
+        loadMusic(context)
     }
 
     /**

app/src/main/java/org/oxycblt/auxio/home/fastscroll/FastScrollRecyclerView.kt

@@ -38,6 +38,7 @@ import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.R
+import org.oxycblt.auxio.util.canScroll
 import org.oxycblt.auxio.util.resolveAttr
 import org.oxycblt.auxio.util.resolveDrawable
 import kotlin.math.abs
@@ -47,13 +48,13 @@ import kotlin.math.abs
  * Zhanghi's AndroidFastScroll but slimmed down for Auxio and with a couple of enhancements.
  *
  * Attributions as per the Apache 2.0 license:
- * ORIGINAL AUTHOR: Zhanghai [https://github.com/zhanghai]
+ * ORIGINAL AUTHOR: Hai Zhang [https://github.com/zhanghai]
  * PROJECT: Android Fast Scroll [https://github.com/zhanghai/AndroidFastScroll]
  * MODIFIER: OxygenCobalt [https://github.com/]
  *
  * !!! MODIFICATIONS !!!:
- * - Scroller will no longer show itself on startup, which looked unpleasent with multiple
+ * - Scroller will no longer show itself on startup or relayouts, which looked unpleasant
- * views
+ * with multiple views
  * - DefaultAnimationHelper and RecyclerViewHelper were merged into the class
  * - FastScroller overlay was merged into RecyclerView instance
  * - Removed FastScrollerBuilder
@@ -65,8 +66,6 @@ import kotlin.math.abs
  * - Added drag listener
  * - TODO: Added documentation
  * - TODO: Popup will center itself to the thumb when possible
- *
- * TODO: Debug this
  */
 class FastScrollRecyclerView @JvmOverloads constructor(
     context: Context,
@@ -193,10 +192,6 @@ class FastScrollRecyclerView @JvmOverloads constructor(
         })
     }
 
-    fun addPopupProvider(provider: (Int) -> String) {
-        popupProvider = provider
-    }
-
     // --- RECYCLERVIEW EVENT MANAGEMENT ---
 
     private fun onPreDraw() {
@@ -316,6 +311,10 @@ class FastScrollRecyclerView @JvmOverloads constructor(
     }
 
     private fun updateScrollbarState() {
+        if (!canScroll() || childCount == 0) {
+            return
+        }
+
         // Getting a pixel-perfect scroll position from a recyclerview is a bit of an involved
         // process. It's kind of expected given how RecyclerView well...recycles views, but it's
         // still very annoying how many hoops one has to jump through.

app/src/main/java/org/oxycblt/auxio/home/fastscroll/Md2PopupBackground.kt

@@ -39,7 +39,7 @@ import kotlin.math.sqrt
  * This is an adaptation from AndroidFastScroll's MD2 theme.
  *
  * Attributions as per the Apache 2.0 license:
- * ORIGINAL AUTHOR: Zhanghai [https://github.com/zhanghai]
+ * ORIGINAL AUTHOR: Hai Zhang [https://github.com/zhanghai]
  * PROJECT: Android Fast Scroll [https://github.com/zhanghai/AndroidFastScroll]
  * MODIFIER: OxygenCobalt [https://github.com/]
  *
@@ -47,7 +47,6 @@ import kotlin.math.sqrt
  * - Use modified Auxio resources instead of AFS resources
  * - Variable names are no longer prefixed with m
  * - Suppressed deprecation warning when dealing with convexness
- * - TODO: Popup will center itself to the thumb when possible
  */
 class Md2PopupBackground(context: Context) : Drawable() {
     private val paint: Paint = Paint()

app/src/main/java/org/oxycblt/auxio/home/list/SongListFragment.kt

@@ -29,7 +29,6 @@ import org.oxycblt.auxio.ui.SongViewHolder
 import org.oxycblt.auxio.ui.SortMode
 import org.oxycblt.auxio.ui.newMenu
 import org.oxycblt.auxio.ui.sliceArticle
-import org.oxycblt.auxio.util.applySpans
 
 class SongListFragment : HomeListFragment() {
     override fun onCreateView(
@@ -47,7 +46,6 @@ class SongListFragment : HomeListFragment() {
         )
 
         setupRecycler(R.id.home_song_list, adapter, homeModel.songs)
-        binding.homeRecycler.applySpans { it == 0 }
 
         return binding.root
     }

app/src/main/java/org/oxycblt/auxio/loading/LoadingFragment.kt

@@ -1,197 +0,0 @@
-/*
- * Copyright (c) 2021 Auxio Project
- * LoadingFragment.kt is part of Auxio.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package org.oxycblt.auxio.loading
-
-import android.Manifest
-import android.content.pm.PackageManager
-import android.os.Bundle
-import android.view.LayoutInflater
-import android.view.View
-import android.view.ViewGroup
-import androidx.activity.result.contract.ActivityResultContracts
-import androidx.core.content.ContextCompat
-import androidx.fragment.app.Fragment
-import androidx.fragment.app.viewModels
-import androidx.navigation.fragment.findNavController
-import org.oxycblt.auxio.R
-import org.oxycblt.auxio.databinding.FragmentLoadingBinding
-import org.oxycblt.auxio.music.MusicStore
-import org.oxycblt.auxio.util.logD
-
-/**
- * Fragment that handles what to display during the loading process.
- * TODO: Figure out how to phase out the loading screen since
- *  Android 12 is annoyingly stubborn about having one splash
- *  screen and one splash screen only.
- * @author OxygenCobalt
- */
-class LoadingFragment : Fragment() {
-    private val loadingModel: LoadingViewModel by viewModels()
-
-    override fun onCreateView(
-        inflater: LayoutInflater,
-        container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View {
-        val binding = FragmentLoadingBinding.inflate(inflater)
-
-        // Build the permission launcher here as you can only do it in onCreateView/onCreate
-        val permLauncher = registerForActivityResult(
-            ActivityResultContracts.RequestPermission(), ::onPermResult
-        )
-
-        // --- UI SETUP ---
-
-        binding.lifecycleOwner = viewLifecycleOwner
-        binding.loadingModel = loadingModel
-
-        // --- VIEWMODEL SETUP ---
-
-        loadingModel.doGrant.observe(viewLifecycleOwner) { doGrant ->
-            if (doGrant) {
-                permLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
-                loadingModel.doneWithGrant()
-            }
-        }
-
-        loadingModel.response.observe(viewLifecycleOwner) { response ->
-            when (response) {
-                // Success should lead to navigation to the main fragment
-                MusicStore.Response.SUCCESS -> findNavController().navigate(
-                    LoadingFragmentDirections.actionToMain()
-                )
-
-                // Null means that the loading process is going on
-                null -> showLoading(binding)
-
-                // Anything else is an error
-                else -> showError(binding, response)
-            }
-        }
-
-        if (hasNoPermissions()) {
-            // MusicStore.Response.NO_PERMS isnt actually returned by MusicStore, its just
-            // a way to keep the current permission state across device changes
-            loadingModel.notifyNoPermissions()
-        }
-
-        if (loadingModel.response.value == null) {
-            loadingModel.load(requireContext())
-        }
-
-        logD("Fragment created")
-
-        return binding.root
-    }
-
-    override fun onResume() {
-        super.onResume()
-
-        // Navigate away if the music has already been loaded.
-        // This causes a memory leak, but there's nothing I can do about it.
-        if (loadingModel.loaded) {
-            findNavController().navigate(
-                LoadingFragmentDirections.actionToMain()
-            )
-        }
-    }
-
-    // --- PERMISSIONS ---
-
-    /**
-     * Check if Auxio has the permissions to load music
-     */
-    private fun hasNoPermissions(): Boolean {
-        val needRationale = shouldShowRequestPermissionRationale(
-            Manifest.permission.READ_EXTERNAL_STORAGE
-        )
-
-        val notGranted = ContextCompat.checkSelfPermission(
-            requireContext(), Manifest.permission.READ_EXTERNAL_STORAGE
-        ) == PackageManager.PERMISSION_DENIED
-
-        return needRationale || notGranted
-    }
-
-    private fun onPermResult(granted: Boolean) {
-        if (granted) {
-            // If granted, its now safe to load, which will clear the NO_PERMS response
-            // we applied earlier.
-            loadingModel.load(requireContext())
-        }
-    }
-
-    // --- UI DISPLAY ---
-
-    /**
-     * Hide all error elements and return to the loading view
-     */
-    private fun showLoading(binding: FragmentLoadingBinding) {
-        binding.apply {
-            loadingErrorText.visibility = View.INVISIBLE
-            loadingActionButton.visibility = View.INVISIBLE
-            loadingCircle.visibility = View.VISIBLE
-        }
-    }
-
-    /**
-     * Show an error prompt.
-     * @param error The [MusicStore.Response] that this error corresponds to. Ignores
-     * [MusicStore.Response.SUCCESS]
-     */
-    private fun showError(binding: FragmentLoadingBinding, error: MusicStore.Response) {
-        binding.loadingCircle.visibility = View.GONE
-        binding.loadingErrorText.visibility = View.VISIBLE
-        binding.loadingActionButton.visibility = View.VISIBLE
-
-        when (error) {
-            MusicStore.Response.NO_MUSIC -> {
-                binding.loadingErrorText.text = getString(R.string.err_no_music)
-                binding.loadingActionButton.apply {
-                    setText(R.string.lbl_retry)
-                    setOnClickListener {
-                        loadingModel.load(context)
-                    }
-                }
-            }
-
-            MusicStore.Response.FAILED -> {
-                binding.loadingErrorText.text = getString(R.string.err_load_failed)
-                binding.loadingActionButton.apply {
-                    setText(R.string.lbl_retry)
-                    setOnClickListener {
-                        loadingModel.load(context)
-                    }
-                }
-            }
-
-            MusicStore.Response.NO_PERMS -> {
-                binding.loadingErrorText.text = getString(R.string.err_no_perms)
-                binding.loadingActionButton.apply {
-                    setText(R.string.lbl_grant)
-                    setOnClickListener {
-                        loadingModel.grant()
-                    }
-                }
-            }
-
-            else -> {}
-        }
-    }
-}

app/src/main/java/org/oxycblt/auxio/loading/LoadingViewModel.kt

@@ -1,82 +0,0 @@
-/*
- * Copyright (c) 2021 Auxio Project
- * LoadingViewModel.kt is part of Auxio.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package org.oxycblt.auxio.loading
-
-import android.content.Context
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.ViewModel
-import androidx.lifecycle.viewModelScope
-import kotlinx.coroutines.launch
-import org.oxycblt.auxio.music.MusicStore
-
-/**
- * ViewModel responsible for the loading UI and beginning the loading process overall.
- * @author OxygenCobalt
- */
-class LoadingViewModel : ViewModel() {
-    private val mResponse = MutableLiveData<MusicStore.Response?>(null)
-    private val mDoGrant = MutableLiveData(false)
-
-    private var isBusy = false
-
-    /** The last response from [MusicStore]. Null if the loading process is occurring. */
-    val response: LiveData<MusicStore.Response?> = mResponse
-    val doGrant: LiveData<Boolean> = mDoGrant
-    val loaded: Boolean get() = musicStore.loaded
-
-    private val musicStore = MusicStore.getInstance()
-
-    /**
-     * Begin the music loading process. The response from MusicStore is pushed to [response]
-     */
-    fun load(context: Context) {
-        // Dont start a new load if the last one hasnt finished
-        if (isBusy) return
-
-        isBusy = true
-        mResponse.value = null
-
-        viewModelScope.launch {
-            mResponse.value = musicStore.load(context)
-            isBusy = false
-        }
-    }
-
-    /**
-     * Show the grant prompt.
-     */
-    fun grant() {
-        mDoGrant.value = true
-    }
-
-    /**
-     * Mark that the grant prompt is now shown.
-     */
-    fun doneWithGrant() {
-        mDoGrant.value = false
-    }
-
-    /**
-     * Notify this viewmodel that there are no permissions
-     */
-    fun notifyNoPermissions() {
-        mResponse.value = MusicStore.Response.NO_PERMS
-    }
-}

app/src/main/java/org/oxycblt/auxio/music/MusicStore.kt

@@ -18,11 +18,14 @@
 
 package org.oxycblt.auxio.music
 
+import android.Manifest
 import android.annotation.SuppressLint
 import android.content.ContentResolver
 import android.content.Context
+import android.content.pm.PackageManager
 import android.net.Uri
 import android.provider.OpenableColumns
+import androidx.core.content.ContextCompat
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import org.oxycblt.auxio.util.logD
@@ -46,25 +49,20 @@ class MusicStore private constructor() {
     private var mSongs = listOf<Song>()
     val songs: List<Song> get() = mSongs
 
-    /** Marker for whether the music loading process has successfully completed. */
-    var loaded = false
-        private set
-
     /**
      * Load/Sort the entire music library. Should always be ran on a coroutine.
      */
-    suspend fun load(context: Context): Response {
+    private fun load(context: Context): Response {
-        return withContext(Dispatchers.IO) {
-            loadMusicInternal(context)
-        }
-    }
-
-    /**
-     * Do the actual music loading process internally.
-     */
-    private fun loadMusicInternal(context: Context): Response {
         logD("Starting initial music load...")
 
+        val notGranted = ContextCompat.checkSelfPermission(
+            context, Manifest.permission.READ_EXTERNAL_STORAGE
+        ) == PackageManager.PERMISSION_DENIED
+
+        if (notGranted) {
+            return Response.Err(ErrorKind.NO_PERMS)
+        }
+
         try {
             val start = System.currentTimeMillis()
 
@@ -72,7 +70,7 @@ class MusicStore private constructor() {
             loader.load()
 
             if (loader.songs.isEmpty()) {
-                return Response.NO_MUSIC
+                return Response.Err(ErrorKind.NO_MUSIC)
             }
 
             mSongs = loader.songs
@@ -85,12 +83,10 @@ class MusicStore private constructor() {
             logE("Something went horribly wrong.")
             logE(e.stackTraceToString())
 
-            return Response.FAILED
+            return Response.Err(ErrorKind.FAILED)
         }
 
-        loaded = true
+        return Response.Ok(this)
-
-        return Response.SUCCESS
     }
 
     /**
@@ -121,31 +117,77 @@ class MusicStore private constructor() {
     }
 
     /**
-     * Responses that [MusicStore] sends back when a [load] call completes.
+     * A response that [MusicStore] returns when loading music.
+     * And before you ask, yes, I do like rust.
      */
-    enum class Response {
+    sealed class Response {
-        NO_MUSIC, NO_PERMS, FAILED, SUCCESS
+        class Ok(val musicStore: MusicStore) : Response()
+        class Err(val kind: ErrorKind) : Response()
+    }
+
+    enum class ErrorKind {
+        NO_PERMS, NO_MUSIC, FAILED
     }
 
     companion object {
         @Volatile
-        private var INSTANCE: MusicStore? = null
+        private var INSTANCE: Response? = null
 
         /**
-         * Get/Instantiate the single instance of [MusicStore].
+         * Initialize the loading process for this instance. This must be ran on a background
+         * thread. If the instance has already been loaded successfully, then it will be returned
+         * immediately.
          */
-        fun getInstance(): MusicStore {
+        suspend fun initInstance(context: Context): Response {
             val currentInstance = INSTANCE
 
-            if (currentInstance != null) {
+            if (currentInstance is Response.Ok) {
                 return currentInstance
             }
 
+            return withContext(Dispatchers.IO) {
+                val result = MusicStore().load(context)
+
                 synchronized(this) {
-                val newInstance = MusicStore()
+                    INSTANCE = result
-                INSTANCE = newInstance
-                return newInstance
                 }
+
+                result
+            }
+        }
+
+        /**
+         * Maybe get a MusicStore instance.
+         *
+         * @return null if the music store instance is still loading or if the loading process has
+         * encountered an error. An instance is returned otherwise.
+         */
+        fun maybeGetInstance(): MusicStore? {
+            val currentInstance = INSTANCE
+
+            return if (currentInstance is Response.Ok) {
+                currentInstance.musicStore
+            } else {
+                null
+            }
+        }
+
+        /**
+         * Require a MusicStore instance. This function is dangerous and should only be used if
+         * it's guaranteed that the caller's code will only be called after the initial loading
+         * process.
+         */
+        fun requireInstance(): MusicStore {
+            return requireNotNull(maybeGetInstance()) {
+                "MusicStore instance was not loaded or loading failed."
+            }
+        }
+
+        /**
+         * Check if this instance has successfully loaded or not.
+         */
+        fun loaded(): Boolean {
+            return maybeGetInstance() != null
         }
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -99,9 +99,8 @@ class PlaybackViewModel : ViewModel(), PlaybackStateManager.Callback {
         it.slice((mIndex.value!! + 1) until it.size)
     }
 
-    private val playbackManager = PlaybackStateManager.getInstance()
+    private val playbackManager = PlaybackStateManager.maybeGetInstance()
     private val settingsManager = SettingsManager.getInstance()
-    private val musicStore = MusicStore.getInstance()
 
     init {
         playbackManager.addCallback(this)
@@ -173,7 +172,7 @@ class PlaybackViewModel : ViewModel(), PlaybackStateManager.Callback {
      */
     fun playWithUri(uri: Uri, context: Context) {
         // Check if everything is already running to run the URI play
-        if (playbackManager.isRestored && musicStore.loaded) {
+        if (playbackManager.isRestored && MusicStore.loaded()) {
             playWithUriInternal(uri, context)
         } else {
             logD("Cant play this URI right now, waiting...")
@@ -189,18 +188,13 @@ class PlaybackViewModel : ViewModel(), PlaybackStateManager.Callback {
     private fun playWithUriInternal(uri: Uri, context: Context) {
         logD("Playing with uri $uri")
 
+        val musicStore = MusicStore.requireInstance()
+
         musicStore.findSongForUri(uri, context.contentResolver)?.let { song ->
             playSong(song)
         }
     }
 
-    /**
-     * Play all songs
-     */
-    fun playAll() {
-        playbackManager.playAll()
-    }
-
     /**
      * Shuffle all songs
      */
@@ -370,6 +364,7 @@ class PlaybackViewModel : ViewModel(), PlaybackStateManager.Callback {
      * Restore playback on startup. This can do one of two things:
      * - Play a file intent that was given by MainActivity in [playWithUri]
      * - Restore the last playback state if there is no active file intent.
+     * TODO: Re-add this to HomeFragment once state can be restored
      */
     fun setupPlayback(context: Context) {
         val intentUri = mIntentUri

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -38,7 +38,7 @@ import org.oxycblt.auxio.util.logE
  * - If you want to use the playback state in the UI, use [org.oxycblt.auxio.playback.PlaybackViewModel] as it can withstand volatile UIs.
  * - If you want to use the playback state with the ExoPlayer instance or system-side things, use [org.oxycblt.auxio.playback.system.PlaybackService].
  *
- * All access should be done with [PlaybackStateManager.getInstance].
+ * All access should be done with [PlaybackStateManager.maybeGetInstance].
  * @author OxygenCobalt
  */
 class PlaybackStateManager private constructor() {
@@ -132,7 +132,6 @@ class PlaybackStateManager private constructor() {
     val hasPlayed: Boolean get() = mHasPlayed
 
     private val settingsManager = SettingsManager.getInstance()
-    private val musicStore = MusicStore.getInstance()
 
     // --- CALLBACKS ---
 
@@ -164,6 +163,8 @@ class PlaybackStateManager private constructor() {
 
         when (mode) {
             PlaybackMode.ALL_SONGS -> {
+                val musicStore = MusicStore.requireInstance()
+
                 mParent = null
                 mQueue = musicStore.songs.toMutableList()
             }
@@ -231,22 +232,12 @@ class PlaybackStateManager private constructor() {
         updatePlayback(mQueue[0])
     }
 
-    /**
-     * Play all songs.
-     */
-    fun playAll() {
-        mMode = PlaybackMode.ALL_SONGS
-        mQueue = musicStore.songs.toMutableList()
-        mParent = null
-
-        setShuffling(false, keepSong = false)
-        updatePlayback(mQueue[0])
-    }
-
     /**
      * Shuffle all songs.
      */
     fun shuffleAll() {
+        val musicStore = MusicStore.maybeGetInstance() ?: return
+
         mMode = PlaybackMode.ALL_SONGS
         mQueue = musicStore.songs.toMutableList()
         mParent = null
@@ -478,11 +469,17 @@ class PlaybackStateManager private constructor() {
     private fun resetShuffle(keepSong: Boolean, useLastSong: Boolean) {
         val lastSong = if (useLastSong) mQueue[mIndex] else mSong
 
+        val musicStore = MusicStore.requireInstance()
+
         mQueue = when (mMode) {
-            PlaybackMode.IN_ARTIST -> orderSongsInArtist(mParent as Artist)
+            PlaybackMode.ALL_SONGS ->
-            PlaybackMode.IN_ALBUM -> orderSongsInAlbum(mParent as Album)
+                settingsManager.libSongSort.sortSongs(musicStore.songs).toMutableList()
-            PlaybackMode.IN_GENRE -> orderSongsInGenre(mParent as Genre)
+            PlaybackMode.IN_ALBUM ->
-            PlaybackMode.ALL_SONGS -> orderSongs()
+                settingsManager.detailAlbumSort.sortAlbum(mParent as Album).toMutableList()
+            PlaybackMode.IN_ARTIST ->
+                settingsManager.detailArtistSort.sortArtist(mParent as Artist).toMutableList()
+            PlaybackMode.IN_GENRE ->
+                settingsManager.detailGenreSort.sortGenre(mParent as Genre).toMutableList()
         }
 
         if (keepSong) {
@@ -610,8 +607,10 @@ class PlaybackStateManager private constructor() {
         if (playbackState != null) {
             logD("Found playback state $playbackState with queue size ${queueItems.size}")
 
-            unpackFromPlaybackState(playbackState)
+            val musicStore = MusicStore.requireInstance()
-            unpackQueue(queueItems)
+
+            unpackFromPlaybackState(playbackState, musicStore)
+            unpackQueue(queueItems, musicStore)
             doParentSanityCheck()
         }
 
@@ -640,12 +639,12 @@ class PlaybackStateManager private constructor() {
     /**
      * Unpack a [playbackState] into this instance.
      */
-    private fun unpackFromPlaybackState(playbackState: DatabaseState) {
+    private fun unpackFromPlaybackState(playbackState: DatabaseState, musicStore: MusicStore) {
         // Turn the simplified information from PlaybackState into usable data.
 
         // Do queue setup first
         mMode = PlaybackMode.fromInt(playbackState.mode) ?: PlaybackMode.ALL_SONGS
-        mParent = findParent(playbackState.parentHash, mMode)
+        mParent = findParent(playbackState.parentHash, mMode, musicStore)
         mIndex = playbackState.index
 
         // Then set up the current state
@@ -663,7 +662,6 @@ class PlaybackStateManager private constructor() {
      */
     private fun packQueue(): List<DatabaseQueueItem> {
         val unified = mutableListOf<DatabaseQueueItem>()
-
         var queueItemId = 0L
 
         mUserQueue.forEach { song ->
@@ -683,7 +681,7 @@ class PlaybackStateManager private constructor() {
      * Unpack a list of queue items into a queue & user queue.
      * @param queueItems The list of [DatabaseQueueItem]s to unpack.
      */
-    private fun unpackQueue(queueItems: List<DatabaseQueueItem>) {
+    private fun unpackQueue(queueItems: List<DatabaseQueueItem>, musicStore: MusicStore) {
         for (item in queueItems) {
             musicStore.findSongFast(item.songHash, item.albumHash)?.let { song ->
                 if (item.isUserQueue) {
@@ -711,7 +709,7 @@ class PlaybackStateManager private constructor() {
     /**
      * Get a [Parent] from music store given a [hash] and PlaybackMode [mode].
      */
-    private fun findParent(hash: Int, mode: PlaybackMode): Parent? {
+    private fun findParent(hash: Int, mode: PlaybackMode, musicStore: MusicStore): Parent? {
         return when (mode) {
             PlaybackMode.IN_GENRE -> musicStore.genres.find { it.hash == hash }
             PlaybackMode.IN_ARTIST -> musicStore.artists.find { it.hash == hash }
@@ -737,36 +735,6 @@ class PlaybackStateManager private constructor() {
         }
     }
 
-    // --- ORDERING FUNCTIONS ---
-
-    /**
-     * Create an ordered queue based on the main list of songs
-     */
-    private fun orderSongs(): MutableList<Song> {
-        return settingsManager.libSongSort.sortSongs(musicStore.songs).toMutableList()
-    }
-
-    /**
-     * Create an ordered queue based on an [Album].
-     */
-    private fun orderSongsInAlbum(album: Album): MutableList<Song> {
-        return settingsManager.detailAlbumSort.sortAlbum(album).toMutableList()
-    }
-
-    /**
-     * Create an ordered queue based on an [Artist].
-     */
-    private fun orderSongsInArtist(artist: Artist): MutableList<Song> {
-        return settingsManager.detailArtistSort.sortArtist(artist).toMutableList()
-    }
-
-    /**
-     * Create an ordered queue based on a [Genre].
-     */
-    private fun orderSongsInGenre(genre: Genre): MutableList<Song> {
-        return settingsManager.detailGenreSort.sortGenre(genre).toMutableList()
-    }
-
     /**
      * The interface for receiving updates from [PlaybackStateManager].
      * Add the callback to [PlaybackStateManager] using [addCallback],
@@ -796,7 +764,7 @@ class PlaybackStateManager private constructor() {
         /**
          * Get/Instantiate the single instance of [PlaybackStateManager].
          */
-        fun getInstance(): PlaybackStateManager {
+        fun maybeGetInstance(): PlaybackStateManager {
             val currentInstance = INSTANCE
 
             if (currentInstance != null) {

app/src/main/java/org/oxycblt/auxio/playback/system/AudioReactor.kt

@@ -37,7 +37,7 @@ class AudioReactor(
     context: Context,
     private val player: SimpleExoPlayer
 ) : AudioManager.OnAudioFocusChangeListener {
-    private val playbackManager = PlaybackStateManager.getInstance()
+    private val playbackManager = PlaybackStateManager.maybeGetInstance()
     private val settingsManager = SettingsManager.getInstance()
     private val audioManager = context.getSystemServiceSafe(AudioManager::class)
 

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -92,7 +92,7 @@ class PlaybackService : Service(), Player.Listener, PlaybackStateManager.Callbac
     private val systemReceiver = SystemEventReceiver()
 
     // Managers
-    private val playbackManager = PlaybackStateManager.getInstance()
+    private val playbackManager = PlaybackStateManager.maybeGetInstance()
     private val settingsManager = SettingsManager.getInstance()
 
     // State

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackSessionConnector.kt

@@ -39,7 +39,7 @@ class PlaybackSessionConnector(
     private val player: Player,
     private val mediaSession: MediaSessionCompat
 ) : PlaybackStateManager.Callback, Player.Listener, MediaSessionCompat.Callback() {
-    private val playbackManager = PlaybackStateManager.getInstance()
+    private val playbackManager = PlaybackStateManager.maybeGetInstance()
     private val emptyMetadata = MediaMetadataCompat.Builder().build()
 
     init {

app/src/main/java/org/oxycblt/auxio/search/SearchViewModel.kt

@@ -48,7 +48,6 @@ class SearchViewModel : ViewModel() {
     val isNavigating: Boolean get() = mIsNavigating
     val filterMode: DisplayMode? get() = mFilterMode
 
-    private val musicStore = MusicStore.getInstance()
     private val settingsManager = SettingsManager.getInstance()
 
     init {
@@ -60,9 +59,10 @@ class SearchViewModel : ViewModel() {
      * Will push results to [searchResults].
      */
     fun doSearch(query: String, context: Context) {
+        val musicStore = MusicStore.maybeGetInstance()
         mLastQuery = query
 
-        if (query.isEmpty()) {
+        if (query.isEmpty() || musicStore == null) {
             mSearchResults.value = listOf()
 
             return

app/src/main/java/org/oxycblt/auxio/settings/AboutFragment.kt

@@ -29,11 +29,13 @@ import android.view.ViewGroup
 import androidx.core.net.toUri
 import androidx.core.view.updatePadding
 import androidx.fragment.app.Fragment
+import androidx.fragment.app.activityViewModels
 import androidx.navigation.fragment.findNavController
 import com.google.android.material.bottomsheet.BottomSheetDialogFragment
 import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentAboutBinding
+import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.util.applyEdge
 import org.oxycblt.auxio.util.logD
@@ -44,13 +46,14 @@ import org.oxycblt.auxio.util.showToast
  * @author OxygenCobalt
  */
 class AboutFragment : Fragment() {
+    private val homeModel: HomeViewModel by activityViewModels()
+
     override fun onCreateView(
         inflater: LayoutInflater,
         container: ViewGroup?,
         savedInstanceState: Bundle?
     ): View {
         val binding = FragmentAboutBinding.inflate(layoutInflater)
-        val musicStore = MusicStore.getInstance()
 
         binding.applyEdge { bars ->
             binding.aboutAppbar.updatePadding(top = bars.top)
@@ -65,9 +68,17 @@ class AboutFragment : Fragment() {
         binding.aboutCode.setOnClickListener { openLinkInBrowser(LINK_CODEBASE) }
         binding.aboutFaq.setOnClickListener { openLinkInBrowser(LINK_FAQ) }
         binding.aboutLicenses.setOnClickListener { openLinkInBrowser(LINK_LICENSES) }
+
+        homeModel.loaderResponse.observe(viewLifecycleOwner) { response ->
+            val count = when (response) {
+                is MusicStore.Response.Ok -> response.musicStore.songs.size
+                else -> 0
+            }
+
             binding.aboutSongCount.text = getString(
-            R.string.fmt_songs_loaded, musicStore.songs.size
+                R.string.fmt_songs_loaded, count
             )
+        }
 
         logD("Dialog created.")
 

app/src/main/java/org/oxycblt/auxio/util/ViewUtil.kt

@@ -191,10 +191,12 @@ fun View.applyEdge(onApply: (Rect) -> Unit) {
  * Stopgap measure to make edge-to-edge work on views that also have a playback bar.
  * The issue is that while we can apply padding initially, the padding will still be applied
  * when the bar is shown, which is very ungood. We mitigate this by just checking the song state
- * and removing the padding if it isnt available, which works okayish. I think Material Files has
+ * and removing the padding if there is one, which is a stupidly fragile band-aid but it
- * a better implementation of the same fix however, so once I'm able to hack that layout into
+ * works.
- * Auxio things should be better.
+ *
- * TODO: Get rid of this get rid of this get rid of this
+ * TODO: Dumpster this and replace it with a dedicated layout. Only issue with that is how
+ *  nested our layouts are, which basically forces us to do recursion magic. Hai Zhang's Material
+ *  Files layout may help in this task.
  */
 fun View.applyEdgeRespectingBar(
     playbackModel: PlaybackViewModel,

app/src/main/java/org/oxycblt/auxio/widgets/WidgetController.kt

@@ -33,7 +33,7 @@ import org.oxycblt.auxio.settings.SettingsManager
 class WidgetController(private val context: Context) :
     PlaybackStateManager.Callback,
     SettingsManager.Callback {
-    private val playbackManager = PlaybackStateManager.getInstance()
+    private val playbackManager = PlaybackStateManager.maybeGetInstance()
     private val settingsManager = SettingsManager.getInstance()
     private val widget = WidgetProvider()
 

app/src/main/res/layout/fragment_home.xml

@@ -55,6 +55,7 @@
             android:layout_margin="@dimen/spacing_medium"
             android:contentDescription="@string/desc_shuffle_all"
             app:layout_anchor="@id/home_pager"
+            app:tint="?attr/colorControlNormal"
             app:layout_behavior="com.google.android.material.behavior.HideBottomViewOnScrollBehavior"
             app:layout_anchorGravity="bottom|end" />
 

app/src/main/res/layout/fragment_loading.xml

@@ -1,64 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    xmlns:tools="http://schemas.android.com/tools">
-
-    <data>
-
-        <variable
-            name="loadingModel"
-            type="org.oxycblt.auxio.loading.LoadingViewModel" />
-    </data>
-
-    <FrameLayout
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:gravity="center"
-        android:orientation="vertical">
-
-        <androidx.constraintlayout.widget.ConstraintLayout
-            android:id="@+id/loading_panel"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:layout_margin="@dimen/spacing_large"
-            android:animateLayoutChanges="true"
-            android:layout_gravity="center"
-            android:gravity="center"
-            android:orientation="vertical">
-
-            <ProgressBar
-                android:id="@+id/loading_circle"
-                android:layout_width="match_parent"
-                android:layout_height="wrap_content"
-                app:layout_constraintBottom_toBottomOf="@+id/loading_action_button"
-                app:layout_constraintTop_toTopOf="parent" />
-
-            <TextView
-                android:id="@+id/loading_error_text"
-                android:layout_width="match_parent"
-                android:layout_height="wrap_content"
-                android:layout_marginBottom="@dimen/spacing_small"
-                android:fontFamily="@font/inter_semibold"
-                android:textAlignment="center"
-                android:textColor="?android:attr/textColorPrimary"
-                android:textSize="@dimen/text_size_medium"
-                android:visibility="invisible"
-                app:layout_constraintBottom_toTopOf="@+id/loading_action_button"
-                tools:text="No Music Found" />
-
-            <com.google.android.material.button.MaterialButton
-                android:id="@+id/loading_action_button"
-                style="@style/Widget.Auxio.Button.Primary"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:paddingStart="@dimen/spacing_insane"
-                android:paddingEnd="@dimen/spacing_insane"
-                android:text="@string/lbl_retry"
-                android:visibility="invisible"
-                app:layout_constraintBottom_toBottomOf="parent"
-                app:layout_constraintEnd_toEndOf="parent"
-                app:layout_constraintStart_toStartOf="parent" />
-
-        </androidx.constraintlayout.widget.ConstraintLayout>
-    </FrameLayout>
-</layout>

app/src/main/res/navigation/nav_main.xml

@@ -2,23 +2,7 @@
 <navigation xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
-    app:startDestination="@id/loading_fragment">
+    app:startDestination="@id/main_fragment">
-    <fragment
-        android:id="@+id/loading_fragment"
-        android:name="org.oxycblt.auxio.loading.LoadingFragment"
-        android:label="LoadingFragment"
-        tools:layout="@layout/fragment_loading">
-        <action
-            android:id="@+id/action_to_main"
-            app:destination="@id/main_fragment"
-            app:enterAnim="@anim/nav_default_enter_anim"
-            app:exitAnim="@anim/nav_default_exit_anim"
-            app:launchSingleTop="true"
-            app:popEnterAnim="@anim/nav_default_pop_enter_anim"
-            app:popExitAnim="@anim/nav_default_pop_exit_anim"
-            app:popUpTo="@id/loading_fragment"
-            app:popUpToInclusive="true" />
-    </fragment>
     <fragment
         android:id="@+id/main_fragment"
         android:name="org.oxycblt.auxio.MainFragment"