Added missing chapters count in MangaInfoHeader (#9184)

* Added missing chapters count in MangaInfoHeader

* Added "Might be missing chapters"

* Added missing chapters to MangaAndSourceTitlesLarge function

* Removed comments

* Reworked getMissingChapters to countMissingChapters, moved -1 check

* Attempting detecting sub-chapters

* Moved MissingChapters to ChapterHeader; Adapted design to fit in

* Fixed block comment in one-line-element

* Fixed critical missing-chapter counting bug

* Undid unintentional & unnecessary changes

* Moved & refactored countMissingChapters

* Fixed import order; Mapping chapter object to chapterNumber

* Optimized "No (valid) chapters" detection

---------

Co-authored-by: arkon <[email protected]>

app/src/main/java/eu/kanade/presentation/manga/MangaScreen.kt

@@ -65,6 +65,7 @@ import eu.kanade.tachiyomi.ui.manga.chapterDecimalFormat
 import eu.kanade.tachiyomi.util.lang.toRelativeString
 import eu.kanade.tachiyomi.util.system.copyToClipboard
 import tachiyomi.domain.chapter.model.Chapter
+import tachiyomi.domain.chapter.service.countMissingChapters
 import tachiyomi.domain.manga.model.Manga
 import tachiyomi.domain.source.model.StubSource
 import tachiyomi.presentation.core.components.LazyColumn
@@ -393,6 +394,7 @@ private fun MangaScreenSmallImpl(
                         ChapterHeader(
                             enabled = chapters.fastAll { !it.selected },
                             chapterCount = chapters.size,
+                            missingChapters = countMissingChapters(chapters.map { it.chapter.chapterNumber }),
                             onClick = onFilterClicked,
                         )
                     }
@@ -604,6 +606,7 @@ fun MangaScreenLargeImpl(
                                 ChapterHeader(
                                     enabled = chapters.fastAll { !it.selected },
                                     chapterCount = chapters.size,
+                                    missingChapters = countMissingChapters(chapters.map { it.chapter.chapterNumber }),
                                     onClick = onFilterButtonClicked,
                                 )
                             }

app/src/main/java/eu/kanade/presentation/manga/components/ChapterHeader.kt

@@ -4,6 +4,9 @@ import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AssistChip
+import androidx.compose.material3.AssistChipDefaults.assistChipColors
+import androidx.compose.material3.AssistChipDefaults.assistChipElevation
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -11,6 +14,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import eu.kanade.tachiyomi.R
 
@@ -18,6 +22,7 @@ import eu.kanade.tachiyomi.R
 fun ChapterHeader(
     enabled: Boolean,
     chapterCount: Int?,
+    missingChapters: Int?,
     onClick: () -> Unit,
 ) {
     Row(
@@ -40,5 +45,42 @@ fun ChapterHeader(
             modifier = Modifier.weight(1f),
             color = MaterialTheme.colorScheme.onBackground,
         )
+
+        // Missing chapters
+        if (missingChapters == null) {
+            DrawWarning(
+                text = stringResource(R.string.missing_chapters_unknown),
+            )
+        } else if (missingChapters > 0) {
+            DrawWarning(
+                text = pluralStringResource(
+                    id = R.plurals.missing_chapters,
+                    count = missingChapters,
+                    missingChapters,
+                ),
+            )
+        }
     }
 }
+
+@Composable
+private fun DrawWarning(text: String) {
+    AssistChip(
+        onClick = {
+            // TODO Show missing chapters
+        },
+        label = {
+            Text(
+                text = text,
+                overflow = TextOverflow.Ellipsis,
+                color = MaterialTheme.colorScheme.primary,
+            )
+        },
+        shape = MaterialTheme.shapes.small,
+        border = null,
+        colors = assistChipColors(
+            containerColor = MaterialTheme.colorScheme.surface,
+        ),
+        elevation = assistChipElevation(1.dp),
+    )
+}

domain/src/main/java/tachiyomi/domain/chapter/service/MissingChapters.kt

@@ -0,0 +1,37 @@
+package tachiyomi.domain.chapter.service
+
+import kotlin.math.floor
+
+fun countMissingChapters(chaptersInput: List<Float>): Int? {
+    if (chaptersInput.isEmpty()) {
+        return 0
+    }
+
+    val chapters = chaptersInput
+        // Remove any invalid chapters
+        .filter { it != -1f }
+        // Convert to integers, as we cannot check if 16.5 is missing
+        .map { floor(it.toDouble()).toInt() }
+        // Only keep unique chapters so that -1 or 16 are not counted multiple times
+        .distinct()
+        .sortedBy { it }
+
+    if (chapters.isEmpty()) {
+        return null
+    }
+
+    var missingChaptersCount = 0
+    var previousChapter = 0 // The actual chapter number, not the array index
+
+    // We go from 0 to lastChapter - Make sure to use the current index instead of the value
+    for (i in chapters.indices) {
+        val currentChapter = chapters[i]
+        if (currentChapter > previousChapter + 1) {
+            // Add the amount of missing chapters
+            missingChaptersCount += currentChapter - previousChapter - 1
+        }
+        previousChapter = currentChapter
+    }
+
+    return missingChaptersCount
+}

i18n/src/main/res/values/strings.xml

@@ -612,6 +612,11 @@
     <string name="date">Date</string>
 
     <!-- Manga info -->
+    <plurals name="missing_chapters">
+        <item quantity="one">Missing %1$s chapter</item>
+        <item quantity="other">Missing %1$s chapters</item>
+    </plurals>
+    <string name="missing_chapters_unknown">Might be missing chapters</string>
     <string name="ongoing">Ongoing</string>
     <string name="unknown">Unknown</string>
     <string name="unknown_author">Unknown author</string>