Dynamic chapters loading

app/build.gradle

@@ -52,7 +52,7 @@ androidExtensions {
 	experimental = true
 }
 dependencies {
-	implementation fileTree(dir: "libs", include: ["*.jar"])
+	implementation fileTree(dir: "libs", include: ["*.jar", "*.aar"])
 	implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3'
 	implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.3'

app/src/main/java/org/koitharu/kotatsu/KotatsuApp.kt

@@ -6,6 +6,7 @@ import androidx.room.Room
 import coil.Coil
 import coil.ImageLoader
 import coil.util.CoilUtils
+import com.itkacher.okhttpprofiler.OkHttpProfilerInterceptor
 import okhttp3.OkHttpClient
 import org.koin.android.ext.koin.androidContext
 import org.koin.android.ext.koin.androidLogger
@@ -80,11 +81,15 @@ class KotatsuApp : Application() {
 		})
 	}
 
-	private fun okHttp() = OkHttpClient.Builder()
-		.connectTimeout(20, TimeUnit.SECONDS)
-		.readTimeout(60, TimeUnit.SECONDS)
-		.writeTimeout(20, TimeUnit.SECONDS)
-		.cookieJar(cookieJar)
+	private fun okHttp() = OkHttpClient.Builder().apply {
+		connectTimeout(20, TimeUnit.SECONDS)
+		readTimeout(60, TimeUnit.SECONDS)
+		writeTimeout(20, TimeUnit.SECONDS)
+		cookieJar(cookieJar)
+		if (BuildConfig.DEBUG) {
+			addInterceptor(OkHttpProfilerInterceptor())
+		}
+	}
 
 	private fun mangaDb() = Room.databaseBuilder(
 		applicationContext,

app/src/main/java/org/koitharu/kotatsu/ui/reader/BaseReaderFragment.kt

@@ -6,10 +6,13 @@ import org.koitharu.kotatsu.core.model.MangaChapter
 import org.koitharu.kotatsu.core.model.MangaPage
 import org.koitharu.kotatsu.core.prefs.ReaderMode
 import org.koitharu.kotatsu.ui.common.BaseFragment
+import java.util.*
 
 abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragment(contentLayoutId),
 	ReaderView {
 
+	private val chaptersMap = ArrayDeque<Pair<Long, Int>>() as Deque<Pair<Long, Int>>
+
 	protected val lastState
 		get() = (activity as? ReaderActivity)?.state
 
@@ -42,4 +45,85 @@ abstract class BaseReaderFragment(@LayoutRes contentLayoutId: Int) : BaseFragmen
 	override fun onInitReader(mode: ReaderMode) = Unit
 
 	override fun onChaptersLoader(chapters: List<MangaChapter>) = Unit
+
+	final override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
+		when {
+			chaptersMap.isEmpty() -> {
+				chaptersMap.push(chapterId to pages.size)
+				onPagesLoaded(chapterId, pages, Action.REPLACE)
+			}
+			shouldAppend(chapterId) -> {
+				chaptersMap.addLast(chapterId to pages.size)
+				onPagesLoaded(chapterId, pages, Action.APPEND)
+			}
+			shouldPrepend(chapterId) -> {
+				chaptersMap.addFirst(chapterId to pages.size)
+				onPagesLoaded(chapterId, pages, Action.PREPEND)
+			}
+			else -> {
+				chaptersMap.clear()
+				chaptersMap.push(chapterId to pages.size)
+				onPagesLoaded(chapterId, pages, Action.REPLACE)
+			}
+		}
+	}
+
+	private fun shouldAppend(chapterId: Long): Boolean {
+		val chapters = lastState?.manga?.chapters ?: return false
+		val lastChapterId = chaptersMap.peekLast()?.first ?: return false
+		val indexOfCurrent = chapters.indexOfLast { x -> x.id == lastChapterId }
+		val indexOfNext = chapters.indexOfLast { x -> x.id == chapterId }
+		return indexOfCurrent != -1 && indexOfNext != -1 && indexOfCurrent + 1 == indexOfNext
+	}
+
+	private fun shouldPrepend(chapterId: Long): Boolean {
+		val chapters = lastState?.manga?.chapters ?: return false
+		val firstChapterId = chaptersMap.peekFirst()?.first ?: return false
+		val indexOfCurrent = chapters.indexOfFirst { x -> x.id == firstChapterId }
+		val indexOfPrev = chapters.indexOfFirst { x -> x.id == chapterId }
+		return indexOfCurrent != -1 && indexOfPrev != -1 && indexOfCurrent + 1 == indexOfPrev
+	}
+
+	protected fun getNextChapterId(): Long {
+		val lastChapterId = chaptersMap.peekLast()?.first ?: return 0
+		val chapters = lastState?.manga?.chapters ?: return 0
+		val indexOfCurrent = chapters.indexOfLast { x -> x.id == lastChapterId }
+		return if (indexOfCurrent == -1) {
+			0
+		} else {
+			chapters.getOrNull(indexOfCurrent + 1)?.id ?: 0
+		}
+	}
+
+	protected fun getPrevChapterId(): Long {
+		val firstChapterId = chaptersMap.peekFirst()?.first ?: return 0
+		val chapters = lastState?.manga?.chapters ?: return 0
+		val indexOfCurrent = chapters.indexOfFirst { x -> x.id == firstChapterId }
+		return if (indexOfCurrent == -1) {
+			0
+		} else {
+			chapters.getOrNull(indexOfCurrent - 1)?.id ?: 0
+		}
+	}
+
+
+	protected fun notifyPageChanged(page: Int) {
+		var i = page
+		val chapters = lastState?.manga?.chapters ?: return
+		val chapter = chaptersMap.firstOrNull { x ->
+			i -= x.second
+			i <= 0
+		} ?: return
+		(activity as? ReaderListener)?.onPageChanged(
+			chapter = chapters.find { x -> x.id == chapter.first } ?: return,
+			page = i + chapter.second,
+			total = chapter.second
+		)
+	}
+
+	protected abstract fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>, action: Action)
+
+	protected enum class Action {
+		REPLACE, PREPEND, APPEND
+	}
 }

app/src/main/java/org/koitharu/kotatsu/ui/reader/OnBoundsScrollListener.kt

@@ -0,0 +1,8 @@
+package org.koitharu.kotatsu.ui.reader
+
+interface OnBoundsScrollListener {
+
+	fun onScrolledToStart()
+
+	fun onScrolledToEnd()
+}

app/src/main/java/org/koitharu/kotatsu/ui/reader/PageLoader.kt

@@ -45,6 +45,11 @@ class PageLoader : KoinComponent, CoroutineScope, DisposableHandle {
 				.cacheControl(CacheUtils.CONTROL_DISABLED)
 				.build()
 			okHttp.newCall(request).await().use { response ->
+				val body = response.body!!
+				val type = body.contentType()
+				check(type?.type == "image") {
+					"Unexpected content type ${type?.type}/${type?.subtype}"
+				}
 				cache.put(url) { out ->
 					response.body!!.byteStream().copyTo(out)
 				}

app/src/main/java/org/koitharu/kotatsu/ui/reader/ReaderActivity.kt

@@ -34,7 +34,8 @@ import org.koitharu.kotatsu.utils.anim.Motion
 import org.koitharu.kotatsu.utils.ext.*
 
 class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnChapterChangeListener,
-	GridTouchHelper.OnGridTouchListener, OnPageSelectListener, ReaderConfigDialog.Callback {
+	GridTouchHelper.OnGridTouchListener, OnPageSelectListener, ReaderConfigDialog.Callback,
+	ReaderListener {
 
 	private val presenter by moxyPresenter(factory = ReaderPresenter.Companion::getInstance)
 
@@ -246,6 +247,14 @@ class ReaderActivity : BaseFullscreenActivity(), ReaderView, ChaptersDialog.OnCh
 		}
 	}
 
+	override fun onPageChanged(chapter: MangaChapter, page: Int, total: Int) {
+		title = chapter.name
+		state.manga.chapters?.run {
+			supportActionBar?.subtitle =
+				getString(R.string.chapter_d_of_d, chapter.number, size)
+		}
+	}
+
 	private fun showWaitWhileLoading() {
 		Toast.makeText(this, R.string.wait_for_loading_finish, Toast.LENGTH_SHORT).apply {
 			setGravity(Gravity.CENTER, 0, 0)

app/src/main/java/org/koitharu/kotatsu/ui/reader/ReaderListener.kt

@@ -0,0 +1,8 @@
+package org.koitharu.kotatsu.ui.reader
+
+import org.koitharu.kotatsu.core.model.MangaChapter
+
+interface ReaderListener {
+
+	fun onPageChanged(chapter: MangaChapter, page: Int, total: Int)
+}

app/src/main/java/org/koitharu/kotatsu/ui/reader/standard/PagerPaginationListener.kt

@@ -0,0 +1,26 @@
+package org.koitharu.kotatsu.ui.reader.standard
+
+import androidx.recyclerview.widget.RecyclerView
+import androidx.viewpager2.widget.ViewPager2
+import org.koitharu.kotatsu.ui.reader.OnBoundsScrollListener
+
+class PagerPaginationListener(
+	private val adapter: RecyclerView.Adapter<*>,
+	private val offset: Int,
+	private val listener: OnBoundsScrollListener
+) : ViewPager2.OnPageChangeCallback() {
+
+	private var lastItemCountStart = 0
+	private var lastItemCountEnd = 0
+
+	override fun onPageSelected(position: Int) {
+		val itemCount = adapter.itemCount
+		if (position <= offset && itemCount != lastItemCountStart) {
+			lastItemCountStart = itemCount
+			listener.onScrolledToStart()
+		} else if (position >= itemCount - offset && itemCount != lastItemCountEnd) {
+			lastItemCountEnd = itemCount
+			listener.onScrolledToEnd()
+		}
+	}
+}

app/src/main/java/org/koitharu/kotatsu/ui/reader/standard/StandardReaderFragment.kt

@@ -7,15 +7,17 @@ import moxy.ktx.moxyPresenter
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.MangaPage
 import org.koitharu.kotatsu.ui.reader.BaseReaderFragment
+import org.koitharu.kotatsu.ui.reader.OnBoundsScrollListener
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.ReaderPresenter
+import org.koitharu.kotatsu.utils.ext.doOnPageChanged
 
-class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_standard) {
+class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_standard),
+	OnBoundsScrollListener {
 
 	private val presenter by moxyPresenter(factory = ReaderPresenter.Companion::getInstance)
 
 	private var adapter: PagesAdapter? = null
-	private var isBusy: Boolean = true
 	private lateinit var loader: PageLoader
 
 	override fun onCreate(savedInstanceState: Bundle?) {
@@ -28,6 +30,8 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 		adapter = PagesAdapter(loader)
 		pager.adapter = adapter
 		pager.offscreenPageLimit = 2
+		pager.registerOnPageChangeCallback(PagerPaginationListener(adapter!!, 2, this))
+		pager.doOnPageChanged(::notifyPageChanged)
 	}
 
 	override fun onDestroyView() {
@@ -35,16 +39,19 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 		super.onDestroyView()
 	}
 
-	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
-		adapter?.let {
-			it.replaceData(pages)
-			lastState?.let { state ->
-				if (chapterId == state.chapterId) {
-					pager.setCurrentItem(state.page, false)
+	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>, action: Action) {
+		when (action) {
+			Action.REPLACE -> adapter?.let {
+				it.replaceData(pages)
+				lastState?.let { state ->
+					if (chapterId == state.chapterId) {
+						pager.setCurrentItem(state.page, false)
+					}
 				}
 			}
+			Action.PREPEND -> adapter?.prependData(pages)
+			Action.APPEND -> adapter?.appendData(pages)
 		}
-		isBusy = false
 	}
 
 	override fun onDestroy() {
@@ -52,6 +59,20 @@ class StandardReaderFragment : BaseReaderFragment(R.layout.fragment_reader_stand
 		super.onDestroy()
 	}
 
+	override fun onScrolledToStart() {
+		val prevChapterId = getPrevChapterId()
+		if (prevChapterId != 0L) {
+			presenter.loadChapter(lastState?.manga ?: return, prevChapterId)
+		}
+	}
+
+	override fun onScrolledToEnd() {
+		val nextChapterId = getNextChapterId()
+		if (nextChapterId != 0L) {
+			presenter.loadChapter(lastState?.manga ?: return, nextChapterId)
+		}
+	}
+
 	override val hasItems: Boolean
 		get() = adapter?.hasItems == true
 

app/src/main/java/org/koitharu/kotatsu/ui/reader/wetoon/ListPaginationListener.kt

@@ -0,0 +1,29 @@
+package org.koitharu.kotatsu.ui.reader.wetoon
+
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import org.koitharu.kotatsu.ui.reader.OnBoundsScrollListener
+
+class ListPaginationListener(
+	private val offset: Int,
+	private val listener: OnBoundsScrollListener
+) : RecyclerView.OnScrollListener() {
+
+	private var lastItemCountStart = 0
+	private var lastItemCountEnd = 0
+
+	override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+		super.onScrolled(recyclerView, dx, dy)
+		val itemCount = recyclerView.adapter?.itemCount ?: return
+		val layoutManager = (recyclerView.layoutManager as? LinearLayoutManager) ?: return
+		val firstVisiblePosition = layoutManager.findFirstVisibleItemPosition()
+		val lastVisiblePosition = layoutManager.findLastVisibleItemPosition()
+		if (firstVisiblePosition <= offset && itemCount != lastItemCountStart) {
+			lastItemCountStart = itemCount
+			listener.onScrolledToStart()
+		} else if (lastVisiblePosition >= itemCount - offset && itemCount != lastItemCountEnd) {
+			lastItemCountEnd = itemCount
+			listener.onScrolledToEnd()
+		}
+	}
+}

app/src/main/java/org/koitharu/kotatsu/ui/reader/wetoon/WebtoonReaderFragment.kt

@@ -7,11 +7,13 @@ import moxy.ktx.moxyPresenter
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.model.MangaPage
 import org.koitharu.kotatsu.ui.reader.BaseReaderFragment
+import org.koitharu.kotatsu.ui.reader.OnBoundsScrollListener
 import org.koitharu.kotatsu.ui.reader.PageLoader
 import org.koitharu.kotatsu.ui.reader.ReaderPresenter
 import org.koitharu.kotatsu.utils.ext.firstItem
 
-class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoon) {
+class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoon),
+	OnBoundsScrollListener {
 
 	private val presenter by moxyPresenter(factory = ReaderPresenter.Companion::getInstance)
 
@@ -27,16 +29,37 @@ class WebtoonReaderFragment : BaseReaderFragment(R.layout.fragment_reader_webtoo
 		super.onViewCreated(view, savedInstanceState)
 		adapter = WebtoonAdapter(loader)
 		recyclerView.adapter = adapter
+		recyclerView.addOnScrollListener(ListPaginationListener(2, this))
 	}
 
-	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>) {
-		adapter?.let {
-			it.replaceData(pages)
-			lastState?.let { state ->
-				if (chapterId == state.chapterId) {
-					recyclerView.firstItem = state.page
+	override fun onPagesLoaded(chapterId: Long, pages: List<MangaPage>, action: Action) {
+		when(action) {
+			Action.REPLACE -> {
+				adapter?.let {
+					it.replaceData(pages)
+					lastState?.let { state ->
+						if (chapterId == state.chapterId) {
+							recyclerView.firstItem = state.page
+						}
+					}
 				}
 			}
+			Action.PREPEND -> adapter?.prependData(pages)
+			Action.APPEND -> adapter?.appendData(pages)
+		}
+	}
+
+	override fun onScrolledToStart() {
+		val prevChapterId = getPrevChapterId()
+		if (prevChapterId != 0L) {
+			presenter.loadChapter(lastState?.manga ?: return, prevChapterId)
+		}
+	}
+
+	override fun onScrolledToEnd() {
+		val nextChapterId = getNextChapterId()
+		if (nextChapterId != 0L) {
+			presenter.loadChapter(lastState?.manga ?: return, nextChapterId)
 		}
 	}