Created ViewModel

statex-core/src/androidMain/kotlin/com.mooncloak.kodetools.statex/AndroidPlatformViewModel.kt

@@ -1,4 +1,4 @@
 package com.mooncloak.kodetools.statex
 
-internal actual abstract class PlatformViewModel internal actual constructor() :
+actual abstract class PlatformViewModel internal actual constructor() :
     androidx.lifecycle.ViewModel()

statex-core/src/commonMain/kotlin/com.mooncloak.kodetools.statex/PlatformViewModel.kt

@@ -7,4 +7,4 @@ package com.mooncloak.kodetools.statex
  * Android development. Therefore, the Android implementation of this component inherits from the
  * `androidx.lifecycle.ViewModel` component.
  */
-internal expect abstract class PlatformViewModel internal constructor()
+expect abstract class PlatformViewModel internal constructor()

statex-core/src/commonMain/kotlin/com.mooncloak.kodetools.statex/ViewModel.kt

@@ -0,0 +1,144 @@
+package com.mooncloak.kodetools.statex
+
+import androidx.compose.runtime.State
+import kotlinx.coroutines.*
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * A design pattern level component that encapsulates state management and application logic for a user interface
+ * component or concept, such as a screen within an application. A [ViewModel] follows the uni-directional data flow
+ * (UDF) approach recommended by the Jetpack Compose documentation.
+ *
+ * A [ViewModel] exposes a single [StateContainer] of the wrapped [State] values via the [state] property. This [state]
+ * property provides a stream of state changes that occur as a result of the application logic within the [ViewModel]
+ * function, and can be subscribed to inside or outside the context of a `@Composable` function.
+ *
+ * Functions within a [ViewModel] should handle performing application logic, coordinating and invoking business logic,
+ * mapping to the appropriate models, and emitting the updated state values as a result of those changes. Publicly
+ * exposed functions will be invoked from the user interface components as a result of some action
+ * (ex: user interaction). It is recommended to keep these functions as non-suspending functions, as a [ViewModel]
+ * contains its own lifecycle and has a [coroutineScope] that can be used to launch coroutines internally. This removes
+ * the need for the call-site to have to wrap the function invocations in a coroutine scope themselves.
+ *
+ * > [!Note]
+ * > A [ViewModel] has its own lifecycle and must be bound to the user interface component (ex: `@Composable` function,
+ * > View, etc.) for it to work correctly.
+ *
+ * ## Example Usage
+ *
+ * ```kotlin
+ * class FeedViewModel : ViewModel(initialStateValue = FeedStateModel()) {
+ *
+ *    fun load() {
+ *        emit(value = state.current.value.copy(isLoading = true))
+ *
+ *        val items = withContext(Dispatchers.IO) {
+ *            feedApi.load()
+ *        }
+ *
+ *        emit(value = state.current.value.copy(isLoading = false, items = items))
+ *    }
+ * }
+ * ```
+ *
+ * @param [initialStateValue] The initial value to provide to the [mutableStateContainer] function when constructing
+ * the [StateContainer] instance for the [state] property.
+ */
+abstract class ViewModel<T>(
+    initialStateValue: T
+) : PlatformViewModel() {
+
+    var isBound = false
+        internal set
+
+    /**
+     * Provides access to the read-only [StateContainer] values. [ViewModel] implementations can mutate the wrapped
+     * state by emitting new state values via the protected [emit] and [reset] functions.
+     *
+     * ## Example Usage:
+     *
+     * ```kotlin
+     * @Composable
+     * fun FeedScreen(
+     *     viewModel: FeedViewModel,
+     *     modifier: Modifier = Modifier
+     * ) {
+     *     // Retrieve and use the compose State<T> value
+     *     val currentState by viewModel.state.current
+     *
+     *     AnimatedVisibility(
+     *         visible = currentState.isLoading // Example usage of the underlying state value
+     *     ) { ... }
+     * }
+     * ```
+     *
+     * @see [StateContainer]
+     */
+    val state: StateContainer<T>
+        get() = mutableStateContainer
+
+    /**
+     * A [CoroutineScope] bound to this [ViewModel]'s lifecycle defined by when the component [isBound]. This can be
+     * used from within [ViewModel] implementations functions to launch coroutines.
+     */
+    protected val coroutineScope: CoroutineScope = object : CoroutineScope {
+
+        override val coroutineContext: CoroutineContext
+            get() = job + Dispatchers.Main
+    }
+
+    private lateinit var job: Job
+
+    private val mutableStateContainer = mutableStateContainerOf(initialStateValue)
+
+    fun bind() {
+        if (!isBound) {
+            job = SupervisorJob()
+            isBound = true
+            onBind()
+        }
+    }
+
+    fun unbind() {
+        if (isBound) {
+            onUnbind()
+            job.cancel()
+            isBound = false
+        }
+    }
+
+    /**
+     * Invoked when this component is bound. This can be useful for startup operations. Remember to invoke the super
+     * implementation as there may be super class logic that needs to be invoked.
+     */
+    protected open fun onBind() {}
+
+    /**
+     * Invoked when this component is unbound. This can be useful for cleanup operations. Remember to invoke the super
+     * implementation as there may be super class logic that needs to be invoked.
+     */
+    protected open fun onUnbind() {}
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    protected fun emit(block: (current: T) -> T) {
+        coroutineScope.launch {
+            mutableStateContainer.change(block = block)
+        }
+    }
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    protected fun emit(value: T) {
+        coroutineScope.launch {
+            mutableStateContainer.change(value = value)
+        }
+    }
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    protected fun reset(initialValue: T = this.state.initial.value) {
+        coroutineScope.launch {
+            mutableStateContainer.reset(initialValue = initialValue)
+        }
+    }
+
+    companion object
+}

statex-core/src/jsMain/kotlin/com/mooncloak/kodetools/statex/JsPlatformViewModel.kt

@@ -1,3 +1,3 @@
 package com.mooncloak.kodetools.statex
 
-internal actual abstract class PlatformViewModel internal actual constructor()
+actual abstract class PlatformViewModel internal actual constructor()

statex-core/src/jvmMain/kotlin/com/mooncloak/kodetools/statex/JvmPlatformViewModel.kt

@@ -1,3 +1,3 @@
 package com.mooncloak.kodetools.statex
 
-internal actual abstract class PlatformViewModel internal actual constructor()
+actual abstract class PlatformViewModel internal actual constructor()

statex-core/src/nativeMain/kotlin/com/mooncloak/kodetools/statex/NativePlatformViewModel.kt

@@ -1,3 +1,3 @@
 package com.mooncloak.kodetools.statex
 
-internal actual abstract class PlatformViewModel internal actual constructor()
+actual abstract class PlatformViewModel internal actual constructor()

statex-core/src/wasmJsMain/kotlin/com/mooncloak/kodetools/statex/WasmJsPlatformViewModel.kt

@@ -1,3 +1,3 @@
 package com.mooncloak.kodetools.statex
 
-internal actual abstract class PlatformViewModel internal actual constructor()
+actual abstract class PlatformViewModel internal actual constructor()