Use server_state.complete_ledgers for Ripple lower bound

src/main/kotlin/io/emeraldpay/dshackle/upstream/ripple/RippleLowerBoundStateDetector.kt

@@ -1,9 +1,13 @@
 package io.emeraldpay.dshackle.upstream.ripple
 
+import io.emeraldpay.dshackle.Defaults
+import io.emeraldpay.dshackle.Global
+import io.emeraldpay.dshackle.upstream.ChainRequest
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.lowerbound.LowerBoundData
 import io.emeraldpay.dshackle.upstream.lowerbound.LowerBoundDetector
 import io.emeraldpay.dshackle.upstream.lowerbound.LowerBoundType
+import io.emeraldpay.dshackle.upstream.rpcclient.ListParams
 import reactor.core.publisher.Flux
 
 class RippleLowerBoundStateDetector(
@@ -15,10 +19,41 @@ class RippleLowerBoundStateDetector(
     }
 
     override fun internalDetectLowerBound(): Flux<LowerBoundData> {
-        return Flux.just(LowerBoundData(1, LowerBoundType.STATE))
+        return upstream.getIngressReader()
+            .read(ChainRequest("server_state", ListParams()))
+            .timeout(Defaults.internalCallsTimeout)
+            .map {
+                val resp = Global.objectMapper.readValue(it.getResult(), RippleState::class.java)
+                parseCompleteLedgersLowerBound(resp.state.completeLedgers)
+            }
+            .filter { it != null }
+            .map { it!! }
+            .flatMapMany { lowerBound ->
+                Flux.fromIterable(listOf(LowerBoundData(lowerBound, LowerBoundType.STATE)))
+            }
     }
 
     override fun types(): Set<LowerBoundType> {
         return setOf(LowerBoundType.STATE)
     }
+
+    private fun parseCompleteLedgersLowerBound(completeLedgers: String?): Long? {
+        if (completeLedgers.isNullOrBlank()) {
+            return null
+        }
+        if (completeLedgers == "empty") {
+            return null
+        }
+
+        return completeLedgers.split(",")
+            .mapNotNull { part ->
+                val token = part.trim()
+                if (token.isEmpty()) {
+                    null
+                } else {
+                    token.substringBefore("-").toLongOrNull()
+                }
+            }
+            .minOrNull()
+    }
 }