battle/battler event API + history buttons in test scene

src/commonMain/kotlin/model/Battle.kt

@@ -1,9 +1,12 @@
 package model
 
 import korlibs.datastructure.*
+import korlibs.datastructure.iterators.*
+import korlibs.io.lang.*
 import korlibs.time.*
+import kotlinx.serialization.Serializable
 
-class Battle(initializer: LoadAction = LoadAction.ZERO) {
+class Battle(val initializer: HistoryEntry.Load = HistoryEntry.Load.ZERO) {
     private val _battlers: MutableList<Battler> =
         initializer.battlers.map { Battler(it, initializer.timestamp) }.toMutableList()
     private val _pendingEffects: PriorityQueue<BattleEffect> =
@@ -12,37 +15,70 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
         private set
 
     /** Full history entries needed for rewinding. Stored from oldest to newest. */
-    private val _history: Deque<HistoryEntry> = Deque()
+    private val _history: Deque<HistoryEntry> = Deque<HistoryEntry>().also { it.add(initializer) }
     /** Actions which will be executed at a later timestamp. */
     private val _pendingActions: PriorityQueue<BattleAction> = PriorityQueue()
     /** Abbreviated history entries used only for saving replay data. Stored from oldest to newest. */
     private val _pastHistory: Queue<BattleAction> = Queue()
 
-    val battlers: List<Battler.Readonly> = _battlers.map { it.asReadonly }
-    val pendingEffects: List<BattleEffect> = _pendingEffects.toList()
-    val history: List<HistoryEntry> = _history.toList()
-    val pendingActions: List<BattleAction> = _pendingActions.toList()
-    val pastHistory: List<BattleAction> = _pastHistory.toList()
+    val battlers: List<Battler.Readonly> get() = _battlers.map { it.asReadonly }
+    val pendingEffects: List<BattleEffect> get() = _pendingEffects.toList()
+    val history: List<HistoryEntry> get() = _history.toList()
+    val pendingActions: List<BattleAction> get() = _pendingActions.toList()
+    val pastHistory: List<BattleAction> get() = _pastHistory.toList()
 
-    init {
-        saveHistoryEntry(initializer)
+    private val eventAPI: EventAPI by lazy { EventAPI(this) }
+
+    constructor(initializer: HistoryEntry.Load, actions: List<BattleAction>, timestamp: TimeSpan? = null):
+        this(initializer) {
+        injectActions(actions)
+        if (timestamp != null) {
+            setTimeTo(timestamp)
+        }
     }
 
-    constructor(actions: List<BattleAction>, timestamp: TimeSpan? = null): this(
-        actions.firstOrNull().run {
-            when (this) {
-                is LoadAction -> this
-                else -> LoadAction.ZERO
+    class EventAPI(private val battle: Battle) {
+        val battlers: List<Battler.Readonly> get() = battle.battlers
+
+        fun addBattler(battler: Battler.Saved) {
+            if (battle._battlers.any { it.id == battler.id }) {
+                throw IllegalArgumentException("Can't add a battler who's already in the fight!")
             }
+            battle._battlers.add(Battler(saved = battler, at = battle.currentTime))
         }
-    ) {
-        if (actions.firstOrNull() is LoadAction) {
-            injectActions(actions.drop(1))
-        } else {
-            injectActions(actions)
+
+        fun removeBattler(id: Battler.Id) {
+            battle._battlers.fastIterateRemove { it.id == id }
         }
-        if (timestamp != null) {
-            setTimeTo(timestamp)
+
+        fun battlers(block: Battler.EventAPI.() -> Unit) {
+            battle._battlers.forEach { it.updateAt(battle.currentTime, block) }
+        }
+
+        fun battler(id: Battler.Id): Battler.Readonly? = battle._battlers.find { it.id == id }?.asReadonly
+
+        fun battler(id: Battler.Id, block: Battler.EventAPI.() -> Unit) {
+            battle._battlers.find { it.id == id }?.updateAt(battle.currentTime, block)
+        }
+
+        fun Battler.Readonly.update(block: Battler.EventAPI.() -> Unit) {
+            battler(id, block)
+        }
+
+        fun Battler.Readonly.remove() {
+            removeBattler(id)
+        }
+
+        fun injectEffect(effect: BattleEffect) {
+            when {
+                effect.timestamp > battle.currentTime -> battle._pendingEffects.add(effect)
+                else -> throw InvalidArgumentException(
+                    "can't inject an effect that would take place now or in the past: $effect")
+            }
+        }
+
+        fun injectEffects(effects: Iterable<BattleEffect>) {
+            effects.forEach { injectEffect(it) }
         }
     }
 
@@ -67,7 +103,7 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
     fun abbreviateHistoryUpTo(timestamp: TimeSpan) {
         while (_history.isNotEmpty() && _history.first.timestamp <= timestamp) {
             val previous = _history.removeFirst()
-            if (previous is ActionHistoryEntry) {
+            if (previous is HistoryEntry.Action) {
                 _pastHistory.enqueue(previous.action)
             }
         }
@@ -97,7 +133,7 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
 
         while (_history.isNotEmpty() && _history.last.timestamp > timestamp) {
             val previous = _history.removeLast()
-            if (previous is ActionHistoryEntry) {
+            if (previous is HistoryEntry.Action) {
                 _pendingActions.add(previous.action)
             }
         }
@@ -153,7 +189,9 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
 
     private fun applyEvent(event: TimedEvent) {
         advanceTimeTo(event.timestamp)
-        with(event) { execute() }
+        with(event) { with(eventAPI) {
+            execute()
+        } }
         saveHistoryEntry(event)
     }
 
@@ -161,17 +199,12 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
         val archivedBattlers = _battlers.map { it.asSaved }
         val archivedEffects = _pendingEffects.toList()
         _history.add(when (entry) {
-            is LoadAction -> ActionHistoryEntry(
-                action = entry,
-                battlers = entry.battlers,
-                pendingEffects = entry.pendingEffects,
-            )
-            is BattleAction -> ActionHistoryEntry(
+            is BattleAction -> HistoryEntry.Action(
                 action = entry,
                 battlers = archivedBattlers,
                 pendingEffects = archivedEffects,
             )
-            is BattleEffect -> EffectHistoryEntry(
+            is BattleEffect -> HistoryEntry.Effect(
                 effect = entry,
                 battlers = archivedBattlers,
                 pendingEffects = archivedEffects,
@@ -183,7 +216,39 @@ class Battle(initializer: LoadAction = LoadAction.ZERO) {
         currentTime = entry.timestamp
         _pendingEffects.clear()
         _pendingEffects.addAll(entry.pendingEffects)
-        _battlers.clear()
-        _battlers.addAll(entry.battlers.map { Battler(it, entry.timestamp) })
+        _battlers.retainAll { live -> entry.battlers.any { saved -> saved.id == live.id } }
+        _battlers.fastForEach {
+            live -> live.revertTo(entry.battlers.find { saved -> saved.id == live.id }!!, entry.timestamp) }
+        if (_battlers.size < entry.battlers.size) {
+            entry.battlers.forEach { saved ->
+                if (!_battlers.any { live -> live.id == saved.id }) {
+                    _battlers.add(Battler(saved, entry.timestamp))
+                }
+            }
+        }
     }
+
+    val asSaved: Saved get() = Saved(
+        currentTime = currentTime,
+        initializer = initializer,
+        history = buildList {
+            addAll(pastHistory)
+            _history.forEach {
+                if (it is HistoryEntry.Action) {
+                    add(it.action)
+                }
+            }
+            addAll(pendingActions)
+        }
+    )
+
+    constructor(saved: Saved):
+        this(initializer = saved.initializer, actions = saved.history, timestamp = saved.currentTime)
+
+    @Serializable
+    data class Saved(
+        val currentTime: TimeSpan,
+        val initializer: HistoryEntry.Load,
+        val history: List<BattleAction>,
+    )
 }

src/commonMain/kotlin/model/BattleAction.kt

@@ -0,0 +1,25 @@
+package model
+
+import korlibs.time.*
+import kotlinx.serialization.Serializable
+
+@Serializable
+/** A [BattleAction] represents some kind of input from a player. */
+sealed class BattleAction: TimedEvent()
+
+@Serializable
+data class MultiHitAction(
+    override val timestamp: TimeSpan,
+    val target: Battler.Id,
+    val hits: Int,
+    val firstHitDelay: TimeSpan,
+    val subsequentHitDelay: TimeSpan,
+    val damage: Double,
+): BattleAction() {
+    override fun Battle.EventAPI.execute() {
+        injectEffect(DamageEffect(timestamp + firstHitDelay, target, damage))
+        for (hit in 2..hits) {
+            injectEffect(DamageEffect(timestamp + firstHitDelay + subsequentHitDelay * (hit - 1), target, damage))
+        }
+    }
+}

src/commonMain/kotlin/model/BattleEffect.kt

@@ -0,0 +1,17 @@
+package model
+
+import korlibs.time.*
+import kotlinx.serialization.Serializable
+
+@Serializable
+/** A [BattleEffect] represents some kind of timed impact on the game as a result of a [BattleAction]. */
+sealed class BattleEffect: TimedEvent()
+
+@Serializable
+data class DamageEffect(override val timestamp: TimeSpan, val id: Battler.Id, val damage: Double): BattleEffect() {
+    override fun Battle.EventAPI.execute() {
+        battler(id) {
+            inflictComposureDamage(damage)
+        }
+    }
+}

src/commonMain/kotlin/model/Battler.kt

@@ -2,6 +2,7 @@ package model
 
 import korlibs.math.*
 import korlibs.time.*
+import kotlinx.serialization.Serializable
 import kotlin.jvm.*
 import kotlin.math.*
 
@@ -28,10 +29,12 @@ data class Battler (
     private var lastEnergy: Double = _energy,
     private var lastStamina: Double = _stamina,
 ) {
-    @JvmInline
+    @JvmInline @Serializable
     value class Id(val v: Int)
 
-    class Editable (private val battler: Battler){
+    private val eventAPI: EventAPI by lazy { EventAPI(this) }
+
+    class EventAPI (private val battler: Battler){
         val id: Id get() = battler.id
         var name: String get() = battler.name
             set(v) { battler._name = v }
@@ -57,6 +60,8 @@ data class Battler (
             set(v) { battler._energyPausedUntil = v }
         val currentUpdate: TimeSpan get() = battler.currentUpdate
 
+        val asSaved: Saved get() = battler.asSaved
+
         fun becomeShaken() {
             composure = health.coerceAtMost(0.0)
             if (shaken) {
@@ -98,6 +103,10 @@ data class Battler (
             stamina = (stamina - cost).coerceAtLeast(0.0)
             energy = (energy - cost).coerceAtLeast(0.0)
         }
+
+        fun revertTo(saved: Saved) {
+            battler.revertTo(previous = saved, at = currentUpdate)
+        }
     }
 
     val name: String get() = _name
@@ -211,10 +220,10 @@ data class Battler (
         }
     }
 
-    fun updateAt(t: TimeSpan, block: Editable.() -> Unit) {
+    fun updateAt(t: TimeSpan, block: EventAPI.() -> Unit) {
         advanceTo(t)
 
-        block(Editable(this))
+        block(eventAPI)
 
         lastUpdate = currentUpdate
         lastShaken = shaken
@@ -286,6 +295,7 @@ data class Battler (
         lastStamina = saved.stamina,
     )
 
+    @Serializable
     data class Saved(
         val id: Id,
 

src/commonMain/kotlin/model/HistoryEntry.kt

@@ -1,6 +1,7 @@
 package model
 
 import korlibs.time.*
+import kotlinx.serialization.*
 
 sealed interface HistoryEntry: Comparable<HistoryEntry> {
     val timestamp: TimeSpan
@@ -10,20 +11,36 @@ sealed interface HistoryEntry: Comparable<HistoryEntry> {
     override fun compareTo(other: HistoryEntry): Int {
         return timestamp.compareTo(other.timestamp)
     }
-}
 
-data class ActionHistoryEntry(
-    val action: BattleAction,
-    override val pendingEffects: List<BattleEffect>,
-    override val battlers: List<Battler.Saved>,
-): HistoryEntry {
-    override val timestamp: TimeSpan get() = action.timestamp
-}
+    @Serializable
+    @SerialName("load")
+    data class Load(
+        override val timestamp: TimeSpan,
+        override val pendingEffects: List<BattleEffect>,
+        override val battlers: List<Battler.Saved>,
+    ): HistoryEntry {
+        companion object{
+            val ZERO = Load(timestamp = TimeSpan.ZERO, battlers = listOf(), pendingEffects = listOf())
+        }
+    }
 
-data class EffectHistoryEntry(
-    val effect: BattleEffect,
-    override val pendingEffects: List<BattleEffect>,
-    override val battlers: List<Battler.Saved>,
-): HistoryEntry {
-    override val timestamp: TimeSpan get() = effect.timestamp
+    @Serializable
+    @SerialName("histAction")
+    data class Action(
+        val action: BattleAction,
+        override val pendingEffects: List<BattleEffect>,
+        override val battlers: List<Battler.Saved>,
+    ): HistoryEntry {
+        override val timestamp: TimeSpan get() = action.timestamp
+    }
+
+    @Serializable
+    @SerialName("histFX")
+    data class Effect(
+        val effect: BattleEffect,
+        override val pendingEffects: List<BattleEffect>,
+        override val battlers: List<Battler.Saved>,
+    ): HistoryEntry {
+        override val timestamp: TimeSpan get() = effect.timestamp
+    }
 }

src/commonMain/kotlin/model/TimedEvent.kt

@@ -1,31 +1,14 @@
 package model
 
 import korlibs.time.*
+import kotlinx.serialization.*
 
-sealed interface TimedEvent: Comparable<TimedEvent> {
-    val timestamp: TimeSpan
-    fun Battle.execute()
+@Serializable
+sealed class TimedEvent: Comparable<TimedEvent> {
+    abstract val timestamp: TimeSpan
+    abstract fun Battle.EventAPI.execute()
 
     override fun compareTo(other: TimedEvent): Int {
         return timestamp.compareTo(other.timestamp)
     }
 }
-
-/** A [BattleEffect] represents some kind of timed impact on the game as a result of a [BattleAction]. */
-sealed interface BattleEffect: TimedEvent
-
-/** A [BattleAction] represents some kind of input from a player. */
-sealed interface BattleAction: TimedEvent
-
-data class LoadAction(
-    override val timestamp: TimeSpan,
-    val battlers: List<Battler.Saved>,
-    val pendingEffects: List<BattleEffect>) : BattleAction {
-    override fun Battle.execute() {
-        throw AssertionError("LoadActions should never be executed normally.")
-    }
-
-    companion object{
-        val ZERO = LoadAction(timestamp = TimeSpan.ZERO, battlers = listOf(), pendingEffects = listOf())
-    }
-}

src/commonMain/kotlin/scenes/BattleScene.kt

@@ -1,5 +1,7 @@
 package scenes
 
+import korlibs.event.*
+import korlibs.korge.input.*
 import korlibs.korge.scene.*
 import korlibs.korge.view.*
 import korlibs.time.*
@@ -8,13 +10,13 @@ import views.*
 import kotlin.math.*
 
 class BattleScene : Scene() {
-    private val battle = Battle(LoadAction(
+    private val battle = Battle(HistoryEntry.Load(
         timestamp = TimeSpan.ZERO,
         battlers = listOf(
             Battler.Saved(
                 id = Battler.Id(0),
                 name = "Us",
-                composure = 0.0,
+                composure = 150.0,
                 health = 150.0,
                 maxHealth = 200.0,
                 energy = 0.0,
@@ -29,7 +31,7 @@ class BattleScene : Scene() {
             Battler.Saved(
                 id = Battler.Id(1),
                 name = "Them",
-                composure = 0.0,
+                composure = 150.0,
                 health = 150.0,
                 maxHealth = 200.0,
                 energy = 0.0,
@@ -64,6 +66,30 @@ class BattleScene : Scene() {
             time += TimeSpan(whole)
             battle.setTimeTo(time)
         }
+
+        keys {
+            justDown(Key.R) {
+                time = TimeSpan.ZERO
+                fractional = 0.0
+                battle.setTimeTo(time)
+            }
+
+            justDown(Key.F) {
+                time += TimeSpan(10_000.0)
+                battle.setTimeTo(time)
+            }
+
+            justDown(Key.V) {
+                battle.injectAction(MultiHitAction(
+                    timestamp = time,
+                    target = Battler.Id(1),
+                    hits = 5,
+                    firstHitDelay = TimeSpan(500.0),
+                    subsequentHitDelay = TimeSpan(100.0),
+                    damage = 5.0,
+                ))
+            }
+        }
     }
 
     override suspend fun SContainer.sceneMain() {