From 31d679c1edf49df76ea37a561871af1f5d13572d Mon Sep 17 00:00:00 2001
From: sychic <47618543+Sychic@users.noreply.github.com>
Date: Sun, 31 Dec 2023 14:13:54 -0500
Subject: [PATCH] feat: async states

---
 .../gg/skytils/skytilsmod/gui/view/state.kt   | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 src/main/kotlin/gg/skytils/skytilsmod/gui/view/state.kt

diff --git a/src/main/kotlin/gg/skytils/skytilsmod/gui/view/state.kt b/src/main/kotlin/gg/skytils/skytilsmod/gui/view/state.kt
new file mode 100644
index 000000000..19b5fe341
--- /dev/null
+++ b/src/main/kotlin/gg/skytils/skytilsmod/gui/view/state.kt
@@ -0,0 +1,66 @@
+/*
+ * Skytils - Hypixel Skyblock Quality of Life Mod
+ * Copyright (C) 2020-2023 Skytils
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package gg.skytils.skytilsmod.gui.view
+
+import gg.essential.elementa.state.BasicState
+import gg.essential.elementa.state.MappedState
+import gg.essential.elementa.state.State
+import gg.skytils.skytilsmod.core.mcScope
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+
+open class LateinitState<T> : State<T>() {
+    internal open var backer: T? = null
+    override fun get(): T =
+        backer ?: error("State should be initialized before get")
+
+    override fun set(value: T) {
+        backer = value
+        super.set(value)
+    }
+}
+
+class AsyncMappedState<T, U>(val state: State<T>, val scope: CoroutineScope = mcScope, val mapper: suspend (T) -> U, initialValue: U? = null) : LateinitState<U>() {
+    override var backer: U? = initialValue
+
+    private var removeListener = state.onSetValue {
+        scope.launch {
+            set(mapper(it))
+        }
+    }
+
+    init {
+        if (state !is LateinitState) {
+            scope.launch {
+                set(mapper(state.get()))
+            }
+        }
+    }
+
+    fun rebind(newState: State<T>) {
+        removeListener()
+        removeListener = state.onSetValue {
+            scope.launch {
+                set(mapper(it))
+            }
+        }
+    }
+}
+
+fun <T, U> State<T>.asyncMap(initialValue: U? = null, scope: CoroutineScope = mcScope, mapper: suspend (T) -> U) = AsyncMappedState(this, scope, mapper, initialValue)
\ No newline at end of file