import assert from "node:assert/strict";
import test from "node:test";

import { reconcileConsultSessionModel } from "../src/lib/consult/session-model-fallback.ts";
import { loadConsultTurnHead } from "../src/lib/consult/turn-prep.ts";
import type { ResolvedLanguageModel } from "../src/mastra/model.ts";

function model(id: string, version: number): ResolvedLanguageModel {
  return {
    id,
    label: id,
    description: "",
    creditCost: 1,
    isDefault: id === "default-model",
    mode: "openai",
    model: { providerId: "openai", modelId: id, apiKey: "sk-test" },
    configVersion: version,
  };
}

test("a session pinned to a deleted version continues on the default model", async () => {
  const writes: Array<string | null> = [];
  const decision = await reconcileConsultSessionModel({
    session: { id: "session-1", model_id: "retired-model", model_config_version: 4 },
    requestedModelId: "retired-model",
    resolveBound: async (modelId) => modelId === "retired-model" ? null : model(modelId, 1),
    loadCatalog: async () => ({
      models: [model("default-model", 2)],
      publicModels: [],
      defaultModelId: "default-model",
      issues: [],
    }),
    persistModelId: async (_sessionId, modelId) => {
      writes.push(modelId);
      return true;
    },
  });
  assert.equal(decision.kind, "ready");
  if (decision.kind !== "ready") return;
  assert.equal(decision.model.id, "default-model");
  assert.equal(decision.session.model_id, "default-model");
  assert.equal(decision.session.model_config_version, 2);
  assert.deepEqual(writes, ["default-model"]);
});

test("the next turn still uses the default when the client sends the deleted model id", async () => {
  const decision = await reconcileConsultSessionModel({
    session: { id: "session-1", model_id: "default-model", model_config_version: 2 },
    requestedModelId: "retired-model",
    resolveBound: async (modelId, version) => {
      if (modelId === "retired-model") return null;
      if (modelId === "default-model" && version === 2) return model("default-model", 2);
      if (modelId === "default-model" && version == null) return model("default-model", 2);
      return null;
    },
    loadCatalog: async () => ({ models: [], publicModels: [], defaultModelId: null, issues: [] }),
    persistModelId: async () => {
      throw new Error("persist should not run");
    },
  });
  assert.equal(decision.kind, "ready");
  if (decision.kind !== "ready") return;
  assert.equal(decision.model.id, "default-model");
});

test("a live different model is still refused as a model change", async () => {
  const decision = await reconcileConsultSessionModel({
    session: { id: "session-1", model_id: "default-model", model_config_version: 2 },
    requestedModelId: "other-model",
    resolveBound: async (modelId) => model(modelId, modelId === "other-model" ? 1 : 2),
    loadCatalog: async () => ({ models: [], publicModels: [], defaultModelId: null, issues: [] }),
    persistModelId: async () => false,
  });
  assert.equal(decision.kind, "changed");
});

test("a deleted version with no default model still reports the model as unavailable", async () => {
  const head = await loadConsultTurnHead({
    parallel: false,
    getUser: async () => ({ data: { user: { id: "user-1" } }, error: null }),
    readPendingDeletion: async () => null,
    readBody: async () => ({ success: true as const, data: { sessionId: "session-1", modelId: "retired-model" } }),
    readSession: async () => ({
      data: { id: "session-1", model_id: "retired-model", model_config_version: 4, session_type: "consultation" },
      error: null,
    }),
    resolveModel: async (): Promise<ResolvedLanguageModel | null> => null,
    reconcileModel: async (chatSession, requestedModelId) => {
      const decision = await reconcileConsultSessionModel({
        session: chatSession,
        requestedModelId,
        resolveBound: async () => null,
        loadCatalog: async () => ({ models: [], publicModels: [], defaultModelId: null, issues: ["default_model_unavailable"] }),
        persistModelId: async () => false,
      });
      if (decision.kind !== "ready") return decision;
      return { kind: "ready" as const, chatSession: decision.session, sessionModel: decision.model };
    },
  });
  assert.equal(head.ok, false);
  if (head.ok) return;
  assert.equal(head.response.status, 503);
  const body = await head.response.json() as { error?: string };
  assert.equal(body.error, "模型暂不可用");
});