fix: normalize delivery routing context

Co-authored-by: adam91holt <adam91holt@users.noreply.github.com>

src/infra/outbound/agent-delivery.ts

@@ -0,0 +1,88 @@
+import { DEFAULT_CHAT_CHANNEL } from "../../channels/registry.js";
+import type { ChannelOutboundTargetMode } from "../../channels/plugins/types.js";
+import type { SessionEntry } from "../../config/sessions.js";
+import { normalizeAccountId } from "../../utils/account-id.js";
+import {
+  INTERNAL_MESSAGE_CHANNEL,
+  isDeliverableMessageChannel,
+  isGatewayMessageChannel,
+  normalizeMessageChannel,
+  type GatewayMessageChannel,
+} from "../../utils/message-channel.js";
+import { resolveSessionDeliveryTarget, type SessionDeliveryTarget } from "./targets.js";
+
+export type AgentDeliveryPlan = {
+  baseDelivery: SessionDeliveryTarget;
+  resolvedChannel: GatewayMessageChannel;
+  resolvedTo?: string;
+  resolvedAccountId?: string;
+  deliveryTargetMode?: ChannelOutboundTargetMode;
+};
+
+export function resolveAgentDeliveryPlan(params: {
+  sessionEntry?: SessionEntry;
+  requestedChannel?: string;
+  explicitTo?: string;
+  accountId?: string;
+  wantsDelivery: boolean;
+}): AgentDeliveryPlan {
+  const requestedRaw =
+    typeof params.requestedChannel === "string" ? params.requestedChannel.trim() : "";
+  const normalizedRequested = requestedRaw ? normalizeMessageChannel(requestedRaw) : undefined;
+  const requestedChannel = normalizedRequested || "last";
+
+  const explicitTo =
+    typeof params.explicitTo === "string" && params.explicitTo.trim()
+      ? params.explicitTo.trim()
+      : undefined;
+
+  const baseDelivery = resolveSessionDeliveryTarget({
+    entry: params.sessionEntry,
+    requestedChannel: requestedChannel === INTERNAL_MESSAGE_CHANNEL ? "last" : requestedChannel,
+    explicitTo,
+  });
+
+  const resolvedChannel = (() => {
+    if (requestedChannel === INTERNAL_MESSAGE_CHANNEL) return INTERNAL_MESSAGE_CHANNEL;
+    if (requestedChannel === "last") {
+      if (baseDelivery.channel && baseDelivery.channel !== INTERNAL_MESSAGE_CHANNEL) {
+        return baseDelivery.channel;
+      }
+      return params.wantsDelivery ? DEFAULT_CHAT_CHANNEL : INTERNAL_MESSAGE_CHANNEL;
+    }
+
+    if (isGatewayMessageChannel(requestedChannel)) return requestedChannel;
+
+    if (baseDelivery.channel && baseDelivery.channel !== INTERNAL_MESSAGE_CHANNEL) {
+      return baseDelivery.channel;
+    }
+    return params.wantsDelivery ? DEFAULT_CHAT_CHANNEL : INTERNAL_MESSAGE_CHANNEL;
+  })();
+
+  const deliveryTargetMode = explicitTo
+    ? "explicit"
+    : isDeliverableMessageChannel(resolvedChannel)
+      ? "implicit"
+      : undefined;
+
+  const resolvedAccountId =
+    normalizeAccountId(params.accountId) ??
+    (deliveryTargetMode === "implicit" ? baseDelivery.accountId : undefined);
+
+  let resolvedTo = explicitTo;
+  if (
+    !resolvedTo &&
+    isDeliverableMessageChannel(resolvedChannel) &&
+    resolvedChannel === baseDelivery.lastChannel
+  ) {
+    resolvedTo = baseDelivery.lastTo;
+  }
+
+  return {
+    baseDelivery,
+    resolvedChannel,
+    resolvedTo,
+    resolvedAccountId,
+    deliveryTargetMode,
+  };
+}