Move CheckboxState to core module

(cherry picked from commit fd7c993b0bfb897ea0770c91e4594367ae9c2316)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/browse/BrowseSourceScreenModel.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryScreenModel.kt

core/src/main/java/tachiyomi/core/preference/CheckboxState.kt

@@ -0,0 +1,47 @@
+package tachiyomi.core.preference
+
+sealed class CheckboxState<T>(open val value: T) {
+
+    abstract fun next(): CheckboxState<T>
+
+    sealed class State<T>(override val value: T) : CheckboxState<T>(value) {
+        data class Checked<T>(override val value: T) : State<T>(value)
+        data class None<T>(override val value: T) : State<T>(value)
+
+        val isChecked: Boolean
+            get() = this is Checked
+
+        override fun next(): CheckboxState<T> {
+            return when (this) {
+                is Checked -> None(value)
+                is None -> Checked(value)
+            }
+        }
+    }
+
+    sealed class TriState<T>(override val value: T) : CheckboxState<T>(value) {
+        data class Include<T>(override val value: T) : TriState<T>(value)
+        data class Exclude<T>(override val value: T) : TriState<T>(value)
+        data class None<T>(override val value: T) : TriState<T>(value)
+
+        override fun next(): CheckboxState<T> {
+            return when (this) {
+                is Exclude -> None(value)
+                is Include -> Exclude(value)
+                is None -> Include(value)
+            }
+        }
+    }
+}
+
+inline fun <T> T.asCheckboxState(condition: (T) -> Boolean): CheckboxState.State<T> {
+    return if (condition(this)) {
+        CheckboxState.State.Checked(this)
+    } else {
+        CheckboxState.State.None(this)
+    }
+}
+
+inline fun <T> List<T>.mapAsCheckboxState(condition: (T) -> Boolean): List<CheckboxState.State<T>> {
+    return this.map { it.asCheckboxState(condition) }
+}