History functionality added

app/src/main/java/xyz/quaver/pupil/util/history.kt

@@ -0,0 +1,74 @@
+package xyz.quaver.pupil.util
+
+import kotlinx.serialization.ImplicitReflectionSerializer
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonConfiguration
+import kotlinx.serialization.parseList
+import kotlinx.serialization.stringify
+import java.io.File
+
+
+class Histories(private val file: File) : ArrayList<Int>() {
+
+    init {
+        if (!file.exists())
+            file.parentFile.mkdirs()
+
+        try {
+            load()
+        } catch (e: Exception) {
+            save()
+        }
+    }
+
+    companion object {
+        lateinit var default: Histories
+
+        fun load(file: File) : Histories {
+            return Histories(file).load()
+        }
+    }
+
+    @UseExperimental(ImplicitReflectionSerializer::class)
+    fun load() : Histories {
+        return apply {
+            super.clear()
+            addAll(
+                Json(JsonConfiguration.Stable).parseList(
+                    file.bufferedReader().use { it.readText() }
+                )
+            )
+        }
+    }
+
+    @UseExperimental(ImplicitReflectionSerializer::class)
+    fun save() {
+        file.writeText(Json(JsonConfiguration.Stable).stringify(this))
+    }
+
+    override fun add(element: Int): Boolean {
+        load()
+
+        if (contains(element))
+            super.remove(element)
+
+        super.add(0, element)
+
+        save()
+
+        return true
+    }
+
+    override fun remove(element: Int): Boolean {
+        load()
+        val retval = super.remove(element)
+        save()
+
+        return retval
+    }
+
+    override fun clear() {
+        super.clear()
+        save()
+    }
+}