From 99b09c8b28a1b610118b3d666bb13c00ffbfa8ae Mon Sep 17 00:00:00 2001
From: InsanusMokrassar <ovsyannikov.alexey95@gmail.com>
Date: Sun, 27 Mar 2022 17:15:23 +0600
Subject: [PATCH] add conflicts resolver for default states managers

---
 CHANGELOG.md                                  |  5 +++--
 .../common/managers/DefaultStatesManager.kt   | 21 +++++++++++++++----
 .../common/managers/InMemoryStatesManager.kt  |  5 +++--
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 577c3a4328f..0d4c555406c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,8 +5,9 @@
 * `Common`:
     * New extensions `Element#onVisibilityChanged`, `Element#onVisible` and `Element#onInvisible`
 * `Coroutines`:
-    * New extension `Element.visibilityFlow()` 
-
+    * New extension `Element.visibilityFlow()`
+* `FSM`:
+    * Now it is possible to resolve conflicts on `startChain`
 
 ## 0.9.16
 
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 4c67a5fbd31..30b899da341 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
@@ -39,13 +39,14 @@ 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
  * [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]
+ * @param onUpdateContextsConflictResolver 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
  */
 open class DefaultStatesManager<T : State>(
     protected val repo: DefaultStatesManagerRepo<T> = InMemoryDefaultStatesManagerRepo(),
-    protected val onContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
+    protected val onStartContextsConflictResolver: suspend (old: T, new: T) -> Boolean = { _, _ -> true },
+    protected val onUpdateContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
 ) : StatesManager<T> {
     protected val _onChainStateUpdated = MutableSharedFlow<Pair<T, T>>(0)
     override val onChainStateUpdated: Flow<Pair<T, T>> = _onChainStateUpdated.asSharedFlow()
@@ -56,6 +57,14 @@ open class DefaultStatesManager<T : State>(
 
     protected val mapMutex = Mutex()
 
+    constructor(
+        repo: DefaultStatesManagerRepo<T>,
+        onContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean
+    ) : this (
+        repo,
+        onUpdateContextsConflictResolver = onContextsConflictResolver
+    )
+
     override suspend fun update(old: T, new: T) = mapMutex.withLock {
         val stateByOldContext: T? = repo.getContextState(old.context)
         when {
@@ -67,7 +76,7 @@ open class DefaultStatesManager<T : State>(
             }
             else -> {
                 val stateOnNewOneContext = repo.getContextState(new.context)
-                if (stateOnNewOneContext == null || onContextsConflictResolver(old, new, stateOnNewOneContext)) {
+                if (stateOnNewOneContext == null || onUpdateContextsConflictResolver(old, new, stateOnNewOneContext)) {
                     stateOnNewOneContext ?.let { endChainWithoutLock(it) }
                     repo.removeState(old)
                     repo.set(new)
@@ -78,7 +87,11 @@ open class DefaultStatesManager<T : State>(
     }
 
     override suspend fun startChain(state: T) = mapMutex.withLock {
-        if (!repo.contains(state.context)) {
+        val stateOnContext = repo.getContextState(state.context)
+        if (stateOnContext == null || onStartContextsConflictResolver(stateOnContext, state)) {
+            stateOnContext ?.let {
+                endChainWithoutLock(it)
+            }
             repo.set(state)
             _onStartChain.emit(state)
         }
diff --git a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/InMemoryStatesManager.kt b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/InMemoryStatesManager.kt
index 323e895b315..3cfe75323ad 100644
--- a/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/InMemoryStatesManager.kt
+++ b/fsm/common/src/commonMain/kotlin/dev/inmo/micro_utils/fsm/common/managers/InMemoryStatesManager.kt
@@ -12,5 +12,6 @@ import kotlinx.coroutines.flow.*
  */
 @Deprecated("Use DefaultStatesManager instead", ReplaceWith("DefaultStatesManager"))
 fun <T: State> InMemoryStatesManager(
-    onContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
-) = DefaultStatesManager(onContextsConflictResolver = onContextsConflictResolver)
+    onStartContextsConflictResolver: suspend (old: T, new: T) -> Boolean = { _, _ -> true },
+    onUpdateContextsConflictResolver: suspend (old: T, new: T, currentNew: T) -> Boolean = { _, _, _ -> true }
+) = DefaultStatesManager(onStartContextsConflictResolver = onStartContextsConflictResolver, onUpdateContextsConflictResolver = onUpdateContextsConflictResolver)