From 8f928e16e1b44059dba124ebb18785d1e4515b8b Mon Sep 17 00:00:00 2001
From: InsanusMokrassar <ovsyannikov.alexey95@gmail.com>
Date: Wed, 16 Mar 2022 18:40:21 +0600
Subject: [PATCH] FSM updates

---
 CHANGELOG.md                                   |  4 ++++
 .../fsm/common/UpdatableStatesMachine.kt       | 14 +++++++++++++-
 .../common/managers/DefaultStatesManager.kt    | 18 +++++++++---------
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63d6ee395de..5a34dbc6b2c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## 0.9.15
 
+* `FSM`:
+    * Rename `DefaultUpdatableStatesMachine#compare` to `DefaultUpdatableStatesMachine#shouldReplaceJob`
+    * `DefaultStatesManager` now is extendable
+
 ## 0.9.14
 
 * `Versions`:
diff --git a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/UpdatableStatesMachine.kt b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/UpdatableStatesMachine.kt
index 8d5a53f41bb..09fc45b506f 100644
--- a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/UpdatableStatesMachine.kt
+++ b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/UpdatableStatesMachine.kt
@@ -26,6 +26,12 @@ open class DefaultUpdatableStatesMachine<T : State>(
 ), UpdatableStatesMachine<T> {
     protected val jobsStates = mutableMapOf<Job, T>()
 
+    /**
+     * Realization of this update will use the [Job] of [previousState] in [statesJobs] and [jobsStates] if
+     * [previousState] is [Optional.presented] and [shouldReplaceJob] has returned true for [previousState] and [actualState]. In
+     * other words, [Job] of [previousState] WILL NOT be replaced with the new one if they are "equal". Equality of
+     * states is solved in [shouldReplaceJob] and can be rewritten in subclasses
+     */
     override suspend fun performStateUpdate(previousState: Optional<T>, actualState: T, scope: CoroutineScope) {
         statesJobsMutex.withLock {
             if (compare(previousState, actualState)) {
@@ -52,7 +58,13 @@ open class DefaultUpdatableStatesMachine<T : State>(
         }
     }
 
-    protected open suspend fun compare(previous: Optional<T>, new: T): Boolean = previous.dataOrNull() != new
+    /**
+     * Compare if [previous] potentially lead to the same behaviour with [new]
+     */
+    protected open suspend fun shouldReplaceJob(previous: Optional<T>, new: T): Boolean = previous.dataOrNull() != new
+
+    @Deprecated("Overwrite shouldReplaceJob instead")
+    protected open suspend fun compare(previous: Optional<T>, new: T): Boolean = shouldReplaceJob(previous, new)
 
     override suspend fun updateChain(currentState: T, newState: T) {
         statesManager.update(currentState, newState)
diff --git a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/DefaultStatesManager.kt b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/DefaultStatesManager.kt
index f1ded976fb9..426b70fd5d6 100644
--- a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/DefaultStatesManager.kt
+++ b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/DefaultStatesManager.kt
@@ -37,24 +37,24 @@ interface DefaultStatesManagerRepo<T : State> {
 
 /**
  * @param repo This repo will be used as repository for storing states. All operations with this repo will happen BEFORE
- * any event will be sent to [onChainStateUpdated], [onStartChain] or [onEndChain]. By default will be used
+ * any event will be sent to [onChainStateUpdated], [onStartChain] or [onEndChain]. By default, will be used
  * [InMemoryDefaultStatesManagerRepo] or you may create custom [DefaultStatesManagerRepo] and pass as [repo] parameter
  * @param onContextsConflictResolver Receive old [State], new one and the state currently placed on new [State.context]
  * key. In case when this callback will returns true, the state placed on [State.context] of new will be replaced by
  * new state by using [endChain] with that state
  */
-class DefaultStatesManager<T : State>(
-    private val repo: DefaultStatesManagerRepo<T> = InMemoryDefaultStatesManagerRepo(),
-    private val onContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
+open class DefaultStatesManager<T : State>(
+    protected val repo: DefaultStatesManagerRepo<T> = InMemoryDefaultStatesManagerRepo(),
+    protected val onContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
 ) : StatesManager<T> {
-    private val _onChainStateUpdated = MutableSharedFlow<Pair<T, T>>(0)
+    protected val _onChainStateUpdated = MutableSharedFlow<Pair<T, T>>(0)
     override val onChainStateUpdated: Flow<Pair<T, T>> = _onChainStateUpdated.asSharedFlow()
-    private val _onStartChain = MutableSharedFlow<T>(0)
+    protected val _onStartChain = MutableSharedFlow<T>(0)
     override val onStartChain: Flow<T> = _onStartChain.asSharedFlow()
-    private val _onEndChain = MutableSharedFlow<T>(0)
+    protected val _onEndChain = MutableSharedFlow<T>(0)
     override val onEndChain: Flow<T> = _onEndChain.asSharedFlow()
 
-    private val mapMutex = Mutex()
+    protected val mapMutex = Mutex()
 
     override suspend fun update(old: T, new: T) = mapMutex.withLock {
         val stateByOldContext: T? = repo.getContextState(old.context)
@@ -83,7 +83,7 @@ class DefaultStatesManager<T : State>(
         }
     }
 
-    private suspend fun endChainWithoutLock(state: T) {
+    protected open suspend fun endChainWithoutLock(state: T) {
         if (repo.getContextState(state.context) == state) {
             repo.removeState(state)
             _onEndChain.emit(state)