Centralize the insert-rejection vocabulary in RejectionReason

Every store spelled its rejection reasons inline — the expired-event
string was duplicated four times across ObservableEventStore and
SQLiteEventStore. RejectionReason now carries the NIP-01 OK
machine-readable prefixes plus the standard store reasons, so
InsertOutcome.Rejected tallies and OK-frame building see one
vocabulary no matter which store produced the outcome.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MfwV3xgMSmfxy16ujGPxGW

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/store/IEventStore.kt

@@ -122,7 +122,7 @@ interface IEventStore : AutoCloseable {
                 insert(event)
                 InsertOutcome.Accepted
             } catch (e: Throwable) {
-                InsertOutcome.Rejected(e.message ?: e::class.simpleName ?: "insert failed")
+                InsertOutcome.Rejected(e.message ?: e::class.simpleName ?: RejectionReason.INSERT_FAILED)
             }
         }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/store/ObservableEventStore.kt

@@ -114,7 +114,7 @@ class ObservableEventStore(
             if (event.kind.isEphemeral()) {
                 outcomes[i] =
                     if (event.isExpired()) {
-                        IEventStore.InsertOutcome.Rejected("blocked: Cannot insert an expired event")
+                        IEventStore.InsertOutcome.Rejected(RejectionReason.EXPIRED)
                     } else {
                         IEventStore.InsertOutcome.Accepted
                     }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/store/RejectionReason.kt

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip01Core.store
+
+/**
+ * The machine-readable insert-rejection vocabulary, shared by every
+ * [IEventStore] implementation so the same condition always rejects with the
+ * same words — a caller tallying [IEventStore.InsertOutcome.Rejected] reasons,
+ * or a relay building `OK false` frames, must never see two stores spell
+ * "duplicate" differently.
+ *
+ * NIP-01: an `OK false` message SHOULD begin with a single-word
+ * machine-readable prefix followed by `:`. The `PREFIX_*` constants are that
+ * vocabulary; the full-sentence constants are the standard reasons the
+ * built-in stores emit. `replaced:` is not in NIP-01 but is the de-facto
+ * prefix (strfry and others) for a replaceable event that lost to a stored
+ * newer version — distinct from `duplicate:` (the exact event is already
+ * held).
+ */
+object RejectionReason {
+    // The NIP-01 machine-readable prefixes.
+    const val PREFIX_DUPLICATE = "duplicate:"
+    const val PREFIX_POW = "pow:"
+    const val PREFIX_BLOCKED = "blocked:"
+    const val PREFIX_RATE_LIMITED = "rate-limited:"
+    const val PREFIX_INVALID = "invalid:"
+    const val PREFIX_RESTRICTED = "restricted:"
+    const val PREFIX_ERROR = "error:"
+
+    /** De-facto prefix (not in NIP-01) for a stale version of a replaceable/addressable event. */
+    const val PREFIX_REPLACED = "replaced:"
+
+    // The standard store reasons.
+    const val DUPLICATE = "duplicate: already have this event"
+    const val EXPIRED = "blocked: Cannot insert an expired event"
+    const val DELETED = "blocked: a deletion event exists"
+    const val VANISHED = "blocked: a request to vanish event exists"
+    const val REPLACED = "replaced: a newer version exists"
+    const val INSERT_FAILED = "error: insert failed"
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip01Core/store/sqlite/SQLiteEventStore.kt

@@ -37,6 +37,7 @@ import com.vitorpamplona.quartz.nip01Core.store.FtsReindexProgress
 import com.vitorpamplona.quartz.nip01Core.store.IEventStore
 import com.vitorpamplona.quartz.nip01Core.store.IdAndTime
 import com.vitorpamplona.quartz.nip01Core.store.RawEvent
+import com.vitorpamplona.quartz.nip01Core.store.RejectionReason
 import com.vitorpamplona.quartz.nip09Deletions.DeletionEvent
 import com.vitorpamplona.quartz.nip40Expiration.isExpired
 import com.vitorpamplona.quartz.nip50Search.strippingSearchExtensions
@@ -433,7 +434,7 @@ class SQLiteEventStore(
     }
 
     suspend fun insertEvent(event: Event) {
-        if (event.isExpired()) throw SQLiteException("blocked: Cannot insert an expired event")
+        if (event.isExpired()) throw SQLiteException(RejectionReason.EXPIRED)
         if (event.kind.isEphemeral()) return
 
         pool.useWriter { db ->
@@ -489,7 +490,7 @@ class SQLiteEventStore(
         delta: LiveIndexDelta?,
     ): IEventStore.InsertOutcome {
         if (event.isExpired()) {
-            return IEventStore.InsertOutcome.Rejected("blocked: Cannot insert an expired event")
+            return IEventStore.InsertOutcome.Rejected(RejectionReason.EXPIRED)
         }
         if (event.kind.isEphemeral()) return IEventStore.InsertOutcome.Accepted
 
@@ -509,7 +510,7 @@ class SQLiteEventStore(
             // ROLLBACK shouldn't mask the original cause.
             runCatching { db.execSQL("ROLLBACK TRANSACTION TO SAVEPOINT $sp") }
             runCatching { db.execSQL("RELEASE SAVEPOINT $sp") }
-            IEventStore.InsertOutcome.Rejected(e.message ?: e::class.simpleName ?: "insert failed")
+            IEventStore.InsertOutcome.Rejected(e.message ?: e::class.simpleName ?: RejectionReason.INSERT_FAILED)
         }
     }
 
@@ -518,7 +519,7 @@ class SQLiteEventStore(
         private val delta: LiveIndexDelta?,
     ) : IEventStore.ITransaction {
         override fun insert(event: Event) {
-            if (event.isExpired()) throw SQLiteException("blocked: Cannot insert an expired event")
+            if (event.isExpired()) throw SQLiteException(RejectionReason.EXPIRED)
             if (event.kind.isEphemeral()) return
 
             innerInsertEvent(event, db, delta)