fix: regenerate from target turn

src/runtime/opencode.ts

@@ -33,6 +33,16 @@ type RuntimeModelOverride = {
 
 export type PermissionReply = "once" | "always" | "reject";
 
+type RuntimeMessage = {
+  info: {
+    id: string;
+    role: string;
+  };
+};
+
+const getRuntimeMessageRole = (message: RuntimeMessage) => message.info.role;
+const getRuntimeMessageId = (message: RuntimeMessage) => message.info.id;
+
 export class OpencodeRuntimeAdapter {
   private clientPromise: Promise<OpencodeClient> | null = null;
   private closeServer: (() => void) | null = null;
@@ -108,17 +118,45 @@ export class OpencodeRuntimeAdapter {
     return response.data;
   }
 
-  async revertLastUserMessage(sessionId: string) {
-    const messages = await this.messages(sessionId, 40);
-    const lastUserMessage = [...messages]
-      .reverse()
-      .find((message) => message.info.role === "user");
+  async removeMessage(sessionId: string, messageId: string) {
+    const client = await this.ensureClient();
+    const response = await client.session.deleteMessage({
+      sessionID: sessionId,
+      messageID: messageId,
+    });
+    return response.data;
+  }
 
-    if (!lastUserMessage) {
-      throw new Error("no user message found to revert");
+  async revertToUserMessage(sessionId: string, options: { userOrdinal: number }) {
+    const messages = await this.messages(sessionId, 80);
+    const userMessages = messages.filter(
+      (message) => getRuntimeMessageRole(message) === "user",
+    );
+    const targetUserMessage = userMessages[options.userOrdinal - 1];
+
+    if (!targetUserMessage) {
+      throw new Error("target user message not found to revert");
     }
 
-    return this.revertMessage(sessionId, lastUserMessage.info.id);
+    const targetMessageId = getRuntimeMessageId(targetUserMessage);
+    const targetIndex = messages.findIndex(
+      (message) => getRuntimeMessageId(message) === targetMessageId,
+    );
+    const messagesToRemove = targetIndex >= 0 ? messages.slice(targetIndex) : [targetUserMessage];
+
+    await this.revertMessage(sessionId, targetMessageId);
+
+    for (const message of messagesToRemove.reverse()) {
+      const messageId = getRuntimeMessageId(message);
+      try {
+        await this.removeMessage(sessionId, messageId);
+      } catch (error) {
+        logger.warn(
+          { err: error, sessionId, messageId },
+          "failed to remove reverted opencode message",
+        );
+      }
+    }
   }
 
   async abortSession(sessionId: string) {