Add missing chapter warning (#985)

* add methods to check for missing chapters

* check for missing chapters in pager reader

* check for missing chapters in webtoon reader

* add new string to strings.xml

for missing chapter warning. can be plural or singular

* create a warning drawable

* make reader transition into separate view

adding missing chapters to current would make it messy so I just did
whatever main tachi did and made a separate view

* linting by android studio while building

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/MissingChapters.kt

@@ -0,0 +1,45 @@
+package eu.kanade.tachiyomi.ui.reader.viewer
+
+import eu.kanade.tachiyomi.data.database.models.Chapter
+import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
+import kotlin.math.floor
+
+private val pattern = Regex("""\d+""")
+
+fun hasMissingChapters(higherReaderChapter: ReaderChapter?, lowerReaderChapter: ReaderChapter?): Boolean {
+    if (higherReaderChapter == null || lowerReaderChapter == null) return false
+    return hasMissingChapters(higherReaderChapter.chapter, lowerReaderChapter.chapter)
+}
+
+fun hasMissingChapters(higherChapter: Chapter?, lowerChapter: Chapter?): Boolean {
+    if (higherChapter == null || lowerChapter == null) return false
+    // Check if name contains a number that is potential chapter number
+    if (!pattern.containsMatchIn(higherChapter.name) || !pattern.containsMatchIn(lowerChapter.name)) return false
+    // Check if potential chapter number was recognized as chapter number
+    if (!higherChapter.isRecognizedNumber || !lowerChapter.isRecognizedNumber) return false
+    return hasMissingChapters(higherChapter.chapter_number, lowerChapter.chapter_number)
+}
+
+fun hasMissingChapters(higherChapterNumber: Float, lowerChapterNumber: Float): Boolean {
+    if (higherChapterNumber < 0f || lowerChapterNumber < 0f) return false
+    return calculateChapterDifference(higherChapterNumber, lowerChapterNumber) > 0f
+}
+
+fun calculateChapterDifference(higherReaderChapter: ReaderChapter?, lowerReaderChapter: ReaderChapter?): Float {
+    if (higherReaderChapter == null || lowerReaderChapter == null) return 0f
+    return calculateChapterDifference(higherReaderChapter.chapter, lowerReaderChapter.chapter)
+}
+
+fun calculateChapterDifference(higherChapter: Chapter?, lowerChapter: Chapter?): Float {
+    if (higherChapter == null || lowerChapter == null) return 0f
+    // Check if name contains a number that is potential chapter number
+    if (!pattern.containsMatchIn(higherChapter.name) || !pattern.containsMatchIn(lowerChapter.name)) return 0f
+    // Check if potential chapter number was recognized as chapter number
+    if (!higherChapter.isRecognizedNumber || !lowerChapter.isRecognizedNumber) return 0f
+    return calculateChapterDifference(higherChapter.chapter_number, lowerChapter.chapter_number)
+}
+
+fun calculateChapterDifference(higherChapterNumber: Float, lowerChapterNumber: Float): Float {
+    if (higherChapterNumber < 0f || lowerChapterNumber < 0f) return 0f
+    return floor(higherChapterNumber) - floor(lowerChapterNumber) - 1f
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/ReaderTransitionView.kt

@@ -0,0 +1,105 @@
+package eu.kanade.tachiyomi.ui.reader.viewer
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.LayoutInflater
+import android.widget.LinearLayout
+import androidx.core.text.bold
+import androidx.core.text.buildSpannedString
+import androidx.core.view.isVisible
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.databinding.ReaderTransitionViewBinding
+import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
+
+class ReaderTransitionView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null) :
+    LinearLayout(context, attrs) {
+
+    private val binding: ReaderTransitionViewBinding =
+        ReaderTransitionViewBinding.inflate(LayoutInflater.from(context), this, true)
+
+    init {
+        layoutParams = LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)
+    }
+
+    fun bind(transition: ChapterTransition) {
+        when (transition) {
+            is ChapterTransition.Prev -> bindPrevChapterTransition(transition)
+            is ChapterTransition.Next -> bindNextChapterTransition(transition)
+        }
+
+        missingChapterWarning(transition)
+    }
+
+    /**
+     * Binds a previous chapter transition on this view and subscribes to the page load status.
+     */
+    private fun bindPrevChapterTransition(transition: ChapterTransition) {
+        val prevChapter = transition.to
+
+        val hasPrevChapter = prevChapter != null
+        binding.lowerText.isVisible = hasPrevChapter
+        if (hasPrevChapter) {
+            binding.upperText.textAlignment = TEXT_ALIGNMENT_TEXT_START
+            binding.upperText.text = buildSpannedString {
+                bold { append(context.getString(R.string.transition_previous)) }
+                append("\n${prevChapter!!.chapter.name}")
+            }
+            binding.lowerText.text = buildSpannedString {
+                bold { append(context.getString(R.string.transition_current)) }
+                append("\n${transition.from.chapter.name}")
+            }
+        } else {
+            binding.upperText.textAlignment = TEXT_ALIGNMENT_CENTER
+            binding.upperText.text = context.getString(R.string.transition_no_previous)
+        }
+    }
+
+    /**
+     * Binds a next chapter transition on this view and subscribes to the load status.
+     */
+    private fun bindNextChapterTransition(transition: ChapterTransition) {
+        val nextChapter = transition.to
+
+        val hasNextChapter = nextChapter != null
+        binding.lowerText.isVisible = hasNextChapter
+        if (hasNextChapter) {
+            binding.upperText.textAlignment = TEXT_ALIGNMENT_TEXT_START
+            binding.upperText.text = buildSpannedString {
+                bold { append(context.getString(R.string.transition_finished)) }
+                append("\n${transition.from.chapter.name}")
+            }
+            binding.lowerText.text = buildSpannedString {
+                bold { append(context.getString(R.string.transition_next)) }
+                append("\n${nextChapter!!.chapter.name}")
+            }
+        } else {
+            binding.upperText.textAlignment = TEXT_ALIGNMENT_CENTER
+            binding.upperText.text = context.getString(R.string.transition_no_next)
+        }
+    }
+
+    private fun missingChapterWarning(transition: ChapterTransition) {
+        if (transition.to == null) {
+            binding.warning.isVisible = false
+            return
+        }
+
+        val hasMissingChapters = when (transition) {
+            is ChapterTransition.Prev -> hasMissingChapters(transition.from, transition.to)
+            is ChapterTransition.Next -> hasMissingChapters(transition.to, transition.from)
+        }
+
+        if (!hasMissingChapters) {
+            binding.warning.isVisible = false
+            return
+        }
+
+        val chapterDifference = when (transition) {
+            is ChapterTransition.Prev -> calculateChapterDifference(transition.from, transition.to)
+            is ChapterTransition.Next -> calculateChapterDifference(transition.to, transition.from)
+        }
+
+        binding.warningText.text = resources.getQuantityString(R.plurals.missing_chapters_warning, chapterDifference.toInt(), chapterDifference.toInt())
+        binding.warning.isVisible = true
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerTransitionHolder.kt

@@ -1,10 +1,6 @@
 package eu.kanade.tachiyomi.ui.reader.viewer.pager
 
 import android.annotation.SuppressLint
-import android.graphics.Typeface
-import android.text.SpannableStringBuilder
-import android.text.Spanned
-import android.text.style.StyleSpan
 import android.view.Gravity
 import android.view.View
 import android.view.ViewGroup
@@ -12,13 +8,13 @@ import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.view.ViewGroup.LayoutParams.WRAP_CONTENT
 import android.widget.LinearLayout
 import android.widget.ProgressBar
-import android.widget.TextView
 import androidx.appcompat.widget.AppCompatTextView
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
 import eu.kanade.tachiyomi.util.system.dpToPx
 import eu.kanade.tachiyomi.widget.ViewPagerAdapter
+import eu.kanade.tachiyomi.ui.reader.viewer.ReaderTransitionView
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
 
@@ -42,16 +38,6 @@ class PagerTransitionHolder(
      */
     private var statusSubscription: Subscription? = null
 
-    /**
-     * Text view used to display the text of the current and next/prev chapters.
-     */
-    private var textView = TextView(context).apply {
-        // if (Build.VERSION.SDK_INT >= 23)
-        // setTextColor(context.getResourceColor(R.attr.))
-        textSize = 17.5F
-        wrapContent()
-    }
-
     /**
      * View container of the current status of the transition page. Child views will be added
      * dynamically.
@@ -67,13 +53,12 @@ class PagerTransitionHolder(
         gravity = Gravity.CENTER
         val sidePadding = 64.dpToPx
         setPadding(sidePadding, 0, sidePadding, 0)
-        addView(textView)
+        val transitionView = ReaderTransitionView(context)
+        addView(transitionView)
         addView(pagesContainer)
 
-        when (transition) {
-            is ChapterTransition.Prev -> bindPrevChapterTransition()
-            is ChapterTransition.Next -> bindNextChapterTransition()
-        }
+        transitionView.bind(transition)
+        transition.to?.let { observeStatus(it) }
     }
 
     /**
@@ -85,56 +70,6 @@ class PagerTransitionHolder(
         statusSubscription = null
     }
 
-    /**
-     * Binds a next chapter transition on this view and subscribes to the load status.
-     */
-    private fun bindNextChapterTransition() {
-        val nextChapter = transition.to
-
-        textView.text = if (nextChapter != null) {
-            SpannableStringBuilder().apply {
-                append(context.getString(R.string.finished_chapter))
-                setSpan(StyleSpan(Typeface.BOLD), 0, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${transition.from.chapter.name}\n\n")
-                val currSize = length
-                append(context.getString(R.string.next_title))
-                setSpan(StyleSpan(Typeface.BOLD), currSize, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${nextChapter.chapter.name}\n\n")
-            }
-        } else {
-            context.getString(R.string.theres_no_next_chapter)
-        }
-
-        if (nextChapter != null) {
-            observeStatus(nextChapter)
-        }
-    }
-
-    /**
-     * Binds a previous chapter transition on this view and subscribes to the page load status.
-     */
-    private fun bindPrevChapterTransition() {
-        val prevChapter = transition.to
-
-        textView.text = if (prevChapter != null) {
-            SpannableStringBuilder().apply {
-                append(context.getString(R.string.current_chapter))
-                setSpan(StyleSpan(Typeface.BOLD), 0, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${transition.from.chapter.name}\n\n")
-                val currSize = length
-                append(context.getString(R.string.previous_title))
-                setSpan(StyleSpan(Typeface.BOLD), currSize, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${prevChapter.chapter.name}\n\n")
-            }
-        } else {
-            context.getString(R.string.theres_no_previous_chapter)
-        }
-
-        if (prevChapter != null) {
-            observeStatus(prevChapter)
-        }
-    }
-
     /**
      * Observes the status of the page list of the next/previous chapter. Whenever there's a new
      * state, the pages container is cleaned up before setting the new state.

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerViewerAdapter.kt

@@ -7,6 +7,7 @@ import eu.kanade.tachiyomi.ui.reader.model.InsertPage
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.ui.reader.model.ViewerChapters
+import eu.kanade.tachiyomi.ui.reader.viewer.hasMissingChapters
 import eu.kanade.tachiyomi.widget.ViewPagerAdapter
 import timber.log.Timber
 import kotlin.math.max
@@ -46,6 +47,10 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
     fun setChapters(chapters: ViewerChapters, forceTransition: Boolean) {
         val newItems = mutableListOf<Any>()
 
+        // Force chapter transition page if there are missing chapters
+        val prevHasMissingChapters = hasMissingChapters(chapters.currChapter, chapters.prevChapter)
+        val nextHasMissingChapters = hasMissingChapters(chapters.nextChapter, chapters.currChapter)
+
         this.forceTransition = forceTransition
         // Add previous chapter pages and transition.
         if (chapters.prevChapter != null) {
@@ -65,7 +70,7 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
         }
 
         // Skip transition page if the chapter is loaded & current page is not a transition page
-        if (forceTransition || chapters.prevChapter?.state !is ReaderChapter.State.Loaded) {
+        if (prevHasMissingChapters || forceTransition || chapters.prevChapter?.state !is ReaderChapter.State.Loaded) {
             newItems.add(ChapterTransition.Prev(chapters.currChapter, chapters.prevChapter))
         }
 
@@ -80,7 +85,7 @@ class PagerViewerAdapter(private val viewer: PagerViewer) : ViewPagerAdapter() {
         // Add next chapter transition and pages.
         nextTransition = ChapterTransition.Next(chapters.currChapter, chapters.nextChapter)
             .also {
-                if (forceTransition ||
+                if (nextHasMissingChapters || forceTransition ||
                     chapters.nextChapter?.state !is ReaderChapter.State.Loaded
                 ) {
                     newItems.add(it)

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonAdapter.kt

@@ -9,6 +9,7 @@ import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.ui.reader.model.ViewerChapters
+import eu.kanade.tachiyomi.ui.reader.viewer.hasMissingChapters
 
 /**
  * RecyclerView Adapter used by this [viewer] to where [ViewerChapters] updates are posted.
@@ -30,6 +31,10 @@ class WebtoonAdapter(val viewer: WebtoonViewer) : RecyclerView.Adapter<RecyclerV
     fun setChapters(chapters: ViewerChapters, forceTransition: Boolean) {
         val newItems = mutableListOf<Any>()
 
+        // Force chapter transition page if there are missing chapters
+        val prevHasMissingChapters = hasMissingChapters(chapters.currChapter, chapters.prevChapter)
+        val nextHasMissingChapters = hasMissingChapters(chapters.nextChapter, chapters.currChapter)
+
         // Add previous chapter pages and transition.
         if (chapters.prevChapter != null) {
             // We only need to add the last few pages of the previous chapter, because it'll be
@@ -41,7 +46,7 @@ class WebtoonAdapter(val viewer: WebtoonViewer) : RecyclerView.Adapter<RecyclerV
         }
 
         // Skip transition page if the chapter is loaded & current page is not a transition page
-        if (forceTransition || chapters.prevChapter?.state !is ReaderChapter.State.Loaded) {
+        if (prevHasMissingChapters || forceTransition || chapters.prevChapter?.state !is ReaderChapter.State.Loaded) {
             newItems.add(ChapterTransition.Prev(chapters.currChapter, chapters.prevChapter))
         }
 
@@ -54,7 +59,7 @@ class WebtoonAdapter(val viewer: WebtoonViewer) : RecyclerView.Adapter<RecyclerV
         currentChapter = chapters.currChapter
 
         // Add next chapter transition and pages.
-        if (forceTransition || chapters.nextChapter?.state !is ReaderChapter.State.Loaded) {
+        if (nextHasMissingChapters || forceTransition || chapters.nextChapter?.state !is ReaderChapter.State.Loaded) {
             newItems.add(ChapterTransition.Next(chapters.currChapter, chapters.nextChapter))
         }
 

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonTransitionHolder.kt

@@ -1,22 +1,17 @@
 package eu.kanade.tachiyomi.ui.reader.viewer.webtoon
 
-import android.graphics.Color
-import android.graphics.Typeface
-import android.text.SpannableStringBuilder
-import android.text.Spanned
-import android.text.style.StyleSpan
 import android.view.Gravity
 import android.view.ViewGroup.LayoutParams.MATCH_PARENT
 import android.view.ViewGroup.LayoutParams.WRAP_CONTENT
 import android.widget.LinearLayout
 import android.widget.ProgressBar
-import android.widget.TextView
 import androidx.appcompat.widget.AppCompatButton
 import androidx.appcompat.widget.AppCompatTextView
 import androidx.core.view.isVisible
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.ui.reader.model.ChapterTransition
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
+import eu.kanade.tachiyomi.ui.reader.viewer.ReaderTransitionView
 import eu.kanade.tachiyomi.util.system.dpToPx
 import rx.Subscription
 import rx.android.schedulers.AndroidSchedulers
@@ -34,14 +29,7 @@ class WebtoonTransitionHolder(
      */
     private var statusSubscription: Subscription? = null
 
-    /**
-     * Text view used to display the text of the current and next/prev chapters.
-     */
-    private var textView = TextView(context).apply {
-        textSize = 17.5F
-        setTextColor(Color.WHITE)
-        wrapContent()
-    }
+    private val transitionView = ReaderTransitionView(context)
 
     /**
      * View container of the current status of the transition page. Child views will be added
@@ -66,7 +54,7 @@ class WebtoonTransitionHolder(
             setMargins(0, childMargins, 0, childMargins)
         }
 
-        layout.addView(textView, childParams)
+        layout.addView(transitionView)
         layout.addView(pagesContainer, childParams)
     }
 
@@ -74,10 +62,8 @@ class WebtoonTransitionHolder(
      * Binds the given [transition] with this view holder, subscribing to its state.
      */
     fun bind(transition: ChapterTransition) {
-        when (transition) {
-            is ChapterTransition.Prev -> bindPrevChapterTransition(transition)
-            is ChapterTransition.Next -> bindNextChapterTransition(transition)
-        }
+        transitionView.bind(transition)
+        transition.to?.let { observeStatus(it, transition) }
     }
 
     /**
@@ -87,56 +73,6 @@ class WebtoonTransitionHolder(
         unsubscribeStatus()
     }
 
-    /**
-     * Binds a next chapter transition on this view and subscribes to the load status.
-     */
-    private fun bindNextChapterTransition(transition: ChapterTransition.Next) {
-        val nextChapter = transition.to
-
-        textView.text = if (nextChapter != null) {
-            SpannableStringBuilder().apply {
-                append(context.getString(R.string.finished_chapter))
-                setSpan(StyleSpan(Typeface.BOLD), 0, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${transition.from.chapter.name}\n\n")
-                val currSize = length
-                append(context.getString(R.string.next_title))
-                setSpan(StyleSpan(Typeface.BOLD), currSize, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${nextChapter.chapter.name}\n\n")
-            }
-        } else {
-            context.getString(R.string.theres_no_next_chapter)
-        }
-
-        if (nextChapter != null) {
-            observeStatus(nextChapter, transition)
-        }
-    }
-
-    /**
-     * Binds a previous chapter transition on this view and subscribes to the page load status.
-     */
-    private fun bindPrevChapterTransition(transition: ChapterTransition.Prev) {
-        val prevChapter = transition.to
-
-        textView.text = if (prevChapter != null) {
-            SpannableStringBuilder().apply {
-                append(context.getString(R.string.current_chapter))
-                setSpan(StyleSpan(Typeface.BOLD), 0, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${transition.from.chapter.name}\n\n")
-                val currSize = length
-                append(context.getString(R.string.previous_title))
-                setSpan(StyleSpan(Typeface.BOLD), currSize, length, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
-                append("\n${prevChapter.chapter.name}\n\n")
-            }
-        } else {
-            context.getString(R.string.theres_no_previous_chapter)
-        }
-
-        if (prevChapter != null) {
-            observeStatus(prevChapter, transition)
-        }
-    }
-
     /**
      * Observes the status of the page list of the next/previous chapter. Whenever there's a new
      * state, the pages container is cleaned up before setting the new state.

app/src/main/res/drawable/ic_warning_white_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M1,21h22L12,2 1,21zM13,18h-2v-2h2v2zM13,14h-2v-4h2v4z" />
+</vector>

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

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout 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"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:layout_gravity="center"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/upper_text"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        android:textAppearance="?attr/textAppearanceSubtitle1"
+        tools:text="Top" />
+
+    <LinearLayout
+        android:id="@+id/warning"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="16dp"
+        android:gravity="center_vertical">
+
+        <ImageView
+            android:layout_width="18dp"
+            android:layout_height="18dp"
+            android:layout_marginEnd="8dp"
+            android:scaleType="fitCenter"
+            app:srcCompat="@drawable/ic_warning_white_24dp"
+            app:tint="?attr/colorError"
+            tools:ignore="ContentDescription" />
+
+        <TextView
+            android:id="@+id/warning_text"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:textAppearance="?attr/textAppearanceSubtitle1"
+            tools:text="Warning" />
+
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/lower_text"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="?attr/textAppearanceSubtitle1"
+        tools:text="Bottom" />
+
+</LinearLayout>

app/src/main/res/values/strings.xml

@@ -479,7 +479,16 @@
         <item quantity="one">%1$d page</item>
         <item quantity="other">%1$d pages</item>
     </plurals>
-
+    <plurals name="missing_chapters_warning">
+        <item quantity="one">There is 1 missing chapter</item>
+        <item quantity="other">There are %d missing chapters</item>
+    </plurals>
+    <string name="transition_finished">Finished:</string>
+    <string name="transition_current">Current:</string>
+    <string name="transition_next">Next:</string>
+    <string name="transition_previous">Previous:</string>
+    <string name="transition_no_next">There\'s no next chapter</string>
+    <string name="transition_no_previous">There\'s no previous chapter</string>
 
     <!-- Manga details -->
     <string name="about_this_">About this %1$s</string>