Cached Tool (#757)

* Cached Tool

* Using MutableMap

core/src/commonMain/kotlin/com/xebia/functional/xef/llm/assistants/CachedTool.kt

@@ -0,0 +1,33 @@
+package com.xebia.functional.xef.llm.assistants
+
+import arrow.fx.coroutines.Atomic
+import arrow.fx.coroutines.timeInMillis
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.days
+
+abstract class CachedTool<Input, Output>(
+  private val cache: Atomic<MutableMap<Input, CachedToolInfo<Output>>>,
+  private val timeCachePolicy: Duration = 1.days
+) : Tool<Input, Output> {
+
+  override suspend fun invoke(input: Input): Output {
+    return cache(input) { onCacheMissed(input) }
+  }
+
+  abstract suspend fun onCacheMissed(input: Input): Output
+
+  private suspend fun cache(input: Input, block: suspend () -> Output): Output {
+    val cachedToolInfo = cache.get().get(input)
+    if (cachedToolInfo != null) {
+      val lastTimeInCache = timeInMillis() - timeCachePolicy.inWholeMilliseconds
+      if (lastTimeInCache > cachedToolInfo.timestamp) {
+        cache.get().remove(input)
+      } else {
+        return cachedToolInfo.response
+      }
+    }
+    val response = block()
+    cache.get().put(input, CachedToolInfo(response, timeInMillis()))
+    return response
+  }
+}

core/src/commonMain/kotlin/com/xebia/functional/xef/llm/assistants/CachedToolInfo.kt

@@ -0,0 +1,3 @@
+package com.xebia.functional.xef.llm.assistants
+
+data class CachedToolInfo<Response>(val response: Response, val timestamp: Long)