refactor: add execution backend selection

src/lib/execution/backend-selector.ts

@@ -0,0 +1,97 @@
+import type { AiAccountStatus, AiProvider } from "@/lib/boss-data";
+import {
+  ALIYUN_QWEN_BACKEND,
+  isReadyAliyunQwenBackend,
+} from "@/lib/execution/backends/aliyun-qwen-backend";
+import {
+  MASTER_CODEX_NODE_BACKEND,
+  isReadyMasterCodexNodeBackend,
+} from "@/lib/execution/backends/master-codex-node-backend";
+import { OPENAI_BACKEND, isReadyOpenAiBackend } from "@/lib/execution/backends/openai-backend";
+
+export interface ExecutionBackendSelectionInput {
+  primary: {
+    provider: AiProvider;
+    status: AiAccountStatus;
+  };
+  backups: Array<{
+    provider: AiProvider;
+    status: AiAccountStatus;
+  }>;
+}
+
+export type ExecutionBackendChoice =
+  | typeof MASTER_CODEX_NODE_BACKEND
+  | typeof OPENAI_BACKEND
+  | typeof ALIYUN_QWEN_BACKEND;
+
+function resolveBackendByProvider(provider: AiProvider): ExecutionBackendChoice {
+  switch (provider) {
+    case "master_codex_node":
+      return MASTER_CODEX_NODE_BACKEND;
+    case "openai_api":
+      return OPENAI_BACKEND;
+    case "aliyun_qwen_api":
+      return ALIYUN_QWEN_BACKEND;
+    default:
+      return MASTER_CODEX_NODE_BACKEND;
+  }
+}
+
+function isReadyBackend(choice: ExecutionBackendChoice, input: ExecutionBackendSelectionInput) {
+  const candidates = [
+    ...(input.primary.provider === choice.provider ? [input.primary] : []),
+    ...input.backups.filter((item) => item.provider === choice.provider),
+  ];
+
+  return candidates.some((candidate) => {
+    switch (choice.backendId) {
+      case "aliyun-qwen":
+        return isReadyAliyunQwenBackend(candidate);
+      case "openai-api":
+        return isReadyOpenAiBackend(candidate);
+      case "master-codex-node":
+        return isReadyMasterCodexNodeBackend(candidate);
+      default:
+        return false;
+    }
+  });
+}
+
+export async function selectExecutionBackend(
+  input: ExecutionBackendSelectionInput,
+): Promise<ExecutionBackendChoice> {
+  return listExecutionBackendChoices(input)[0] ?? resolveBackendByProvider(input.primary.provider);
+}
+
+export function listExecutionBackendChoices(
+  input: ExecutionBackendSelectionInput,
+): ExecutionBackendChoice[] {
+  const primaryBackend = resolveBackendByProvider(input.primary.provider);
+  const ordered: ExecutionBackendChoice[] = [];
+  const seen = new Set<string>();
+
+  const pushBackend = (backend: ExecutionBackendChoice) => {
+    if (seen.has(backend.backendId)) {
+      return;
+    }
+    ordered.push(backend);
+    seen.add(backend.backendId);
+  };
+
+  if (input.primary.status === "ready") {
+    pushBackend(primaryBackend);
+  }
+
+  const orderedBackends: ExecutionBackendChoice[] = [ALIYUN_QWEN_BACKEND, OPENAI_BACKEND, MASTER_CODEX_NODE_BACKEND];
+  for (const backend of orderedBackends) {
+    if (isReadyBackend(backend, input)) {
+      pushBackend(backend);
+    }
+  }
+
+  pushBackend(primaryBackend);
+  return ordered;
+}
+
+export const selectExecutionBackendForTesting = selectExecutionBackend;