feat: expose cache as a map of filtered seed (#775)

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

@@ -19,10 +19,33 @@ abstract class CachedTool<Input, Output>(
     return cache(CachedToolKey(input, seed)) { onCacheMissed(input) }
   }
 
+  /**
+   * Exposes the cache as a [Map] of [Input] to [Output] filtered by instance [seed] and
+   * [timeCachePolicy]. Removes expired cache entries.
+   */
+  suspend fun getCache(): Map<Input, Output> {
+    val lastTimeInCache = timeInMillis() - timeCachePolicy.inWholeMilliseconds
+    val withoutExpired =
+      cache.modify { cachedToolInfo ->
+        // Filter entries belonging to the current seed and have not expired
+        val validEntries =
+          cachedToolInfo
+            .filter { (key, value) ->
+              if (key.seed == seed) lastTimeInCache <= value.timestamp else true
+            }
+            .toMutableMap()
+        // Remove expired entries for the current seed only
+        cachedToolInfo.keys.removeAll { key -> key.seed == seed && !validEntries.containsKey(key) }
+        // Modifies state A, and returns state B
+        Pair(cachedToolInfo, validEntries)
+      }
+    return withoutExpired.map { it.key.value to it.value.value }.toMap()
+  }
+
   abstract suspend fun onCacheMissed(input: Input): Output
 
   private suspend fun cache(input: CachedToolKey<Input>, block: suspend () -> Output): Output {
-    val cachedToolInfo = cache.get().get(input)
+    val cachedToolInfo = cache.get()[input]
     if (cachedToolInfo != null) {
       val lastTimeInCache = timeInMillis() - timeCachePolicy.inWholeMilliseconds
       if (lastTimeInCache > cachedToolInfo.timestamp) {
@@ -32,7 +55,7 @@ abstract class CachedTool<Input, Output>(
       }
     }
     val response = block()
-    cache.get().put(input, CachedToolValue(response, timeInMillis()))
+    cache.get()[input] = CachedToolValue(response, timeInMillis())
     return response
   }
 }