add selector

selector/common/build.gradle

@@ -0,0 +1,17 @@
+plugins {
+    id "org.jetbrains.kotlin.multiplatform"
+    id "org.jetbrains.kotlin.plugin.serialization"
+    id "com.android.library"
+}
+
+apply from: "$mppProjectWithSerializationPresetPath"
+
+kotlin {
+    sourceSets {
+        commonMain {
+            dependencies {
+                api "org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlin_coroutines_version"
+            }
+        }
+    }
+}

selector/common/src/commonMain/kotlin/dev/inmo/micro_utils/selector/Selector.kt

@@ -0,0 +1,85 @@
+package dev.inmo.micro_utils.selector
+
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.sync.Mutex
+
+interface Selector<T> {
+    val selectedItems: List<T>
+    val itemSelected: SharedFlow<T>
+    val itemUnselected: SharedFlow<T>
+
+    suspend fun toggleSelection(element: T)
+}
+
+@Suppress("NOTHING_TO_INLINE")
+inline operator fun <T> Selector<T>.contains(element: T) = selectedItems.contains(element)
+@Suppress("NOTHING_TO_INLINE")
+inline fun <T> Selector<T>.nothingSelected(): Boolean = selectedItems.isEmpty()
+
+class SingleSelector<T>(
+    selectedItem: T? = null,
+    useMutex: Boolean = true
+) : Selector<T> {
+    var selectedItem: T? = selectedItem
+        private set
+    override val selectedItems: List<T>
+        get() = selectedItem ?.let { listOf(it) } ?: emptyList()
+
+    private val _itemSelected = MutableSharedFlow<T>()
+    override val itemSelected: SharedFlow<T> = _itemSelected.asSharedFlow()
+    private val _itemUnselected = MutableSharedFlow<T>()
+    override val itemUnselected: SharedFlow<T> = _itemUnselected.asSharedFlow()
+
+    private val mutex = if (useMutex) {
+        Mutex()
+    } else {
+        null
+    }
+
+    override suspend fun toggleSelection(element: T) {
+        mutex ?.lock()
+        if (selectedItem == element) {
+            selectedItem = null
+            _itemUnselected.emit(element)
+        } else {
+            val previouslySelected = selectedItem
+            selectedItem = null
+            if (previouslySelected != null) {
+                _itemUnselected.emit(previouslySelected)
+            }
+            selectedItem = element
+            _itemSelected.emit(element)
+        }
+        mutex ?.unlock()
+    }
+}
+
+class MultipleSelector<T>(
+    selectedItems: List<T>,
+    useMutex: Boolean = true
+) : Selector<T> {
+    private val _selectedItems: MutableList<T> = selectedItems.toMutableList()
+    override val selectedItems: List<T> = _selectedItems
+
+    private val _itemSelected = MutableSharedFlow<T>()
+    override val itemSelected: SharedFlow<T> = _itemSelected.asSharedFlow()
+    private val _itemUnselected = MutableSharedFlow<T>()
+    override val itemUnselected: SharedFlow<T> = _itemUnselected.asSharedFlow()
+
+    private val mutex = if (useMutex) {
+        Mutex()
+    } else {
+        null
+    }
+
+    override suspend fun toggleSelection(element: T) {
+        mutex ?.lock()
+        if (_selectedItems.remove(element)) {
+            _itemUnselected.emit(element)
+        } else {
+            _selectedItems.add(element)
+            _itemSelected.emit(element)
+        }
+        mutex ?.unlock()
+    }
+}

selector/common/src/main/AndroidManifest.xml

@@ -0,0 +1 @@
+<manifest package="dev.inmo.micro_utils.selector"/>