Assign category positions inside the database

A new category's position is computed by its insert, one after the highest, so two categories created at once can't take the same one. Inserts take a NewCategory rather than a Category whose id and position would be ignored. Reordering places any category missing from the given order after the rest instead of leaving it at a stale position. Restore still creates missing categories all or none, in backup order, and the create dialog no longer accepts an empty name.

domain/src/main/java/tachiyomi/domain/category/interactor/CreateCategoryWithName.kt

@@ -4,7 +4,7 @@ import dev.zacsweers.metro.Inject
 import logcat.LogPriority
 import tachiyomi.core.common.util.lang.withNonCancellableContext
 import tachiyomi.core.common.util.system.logcat
-import tachiyomi.domain.category.model.Category
+import tachiyomi.domain.category.model.NewCategory
 import tachiyomi.domain.category.repository.CategoryRepository
 import tachiyomi.domain.library.service.LibraryPreferences
 
@@ -21,17 +21,8 @@ class CreateCategoryWithName(
         }
 
     suspend fun await(name: String): Result = withNonCancellableContext {
-        val categories = categoryRepository.getAll()
-        val nextOrder = categories.maxOfOrNull { it.order }?.plus(1) ?: 0
-        val newCategory = Category(
-            id = 0,
-            name = name,
-            order = nextOrder,
-            flags = initialFlags,
-        )
-
         try {
-            categoryRepository.insert(newCategory)
+            categoryRepository.insert(NewCategory(name = name, flags = initialFlags))
             Result.Success
         } catch (e: Exception) {
             logcat(LogPriority.ERROR, e)

domain/src/main/java/tachiyomi/domain/category/model/NewCategory.kt

@@ -0,0 +1,6 @@
+package tachiyomi.domain.category.model
+
+data class NewCategory(
+    val name: String,
+    val flags: Long,
+)

domain/src/main/java/tachiyomi/domain/category/repository/CategoryRepository.kt

@@ -2,6 +2,7 @@ package tachiyomi.domain.category.repository
 
 import kotlinx.coroutines.flow.Flow
 import tachiyomi.domain.category.model.Category
+import tachiyomi.domain.category.model.NewCategory
 
 interface CategoryRepository {
 
@@ -15,9 +16,9 @@ interface CategoryRepository {
 
     fun getCategoriesByMangaIdAsFlow(mangaId: Long): Flow<List<Category>>
 
-    suspend fun insert(category: Category)
+    suspend fun insert(category: NewCategory)
 
-    suspend fun insertAll(categories: List<Category>)
+    suspend fun insertAll(categories: List<NewCategory>)
 
     suspend fun updateName(categoryId: Long, name: String)