import { describe, it, expect, beforeEach } from "@jest/globals";
import express from "express";
import request from "supertest";

import {
  buildSandboxRouter,
  recordDispatch,
  advance,
  rejectMessage,
  getMessage,
  listMessages,
  resetSandboxForTests,
  finSignature,
} from "../../src/services/finLink/sandbox";
import {
  createInProcessFinLinkClient,
  createHttpFinLinkClient,
} from "../../src/services/finLink/client";

describe("FIN-link sandbox (gap-analysis v2 §7.1 / §10.6)", () => {
  beforeEach(() => {
    resetSandboxForTests();
  });

  describe("lifecycle (in-memory)", () => {
    it("assigns a FIN reference and records state received", () => {
      const msg = recordDispatch({
        messageType: "MT760",
        payload: "MT760 payload",
        planId: "plan-1",
      });
      expect(msg.reference).toMatch(/^FIN-[0-9A-F]{12}$/);
      expect(msg.state).toBe("received");
      expect(msg.stateHistory).toHaveLength(1);
      expect(msg.planId).toBe("plan-1");
    });

    it("advances deterministically: received -> acknowledged -> accepted -> settled", async () => {
      const msg = recordDispatch({ messageType: "pacs.009", payload: "<pacs.009/>" });
      expect((await advance(msg.reference))!.state).toBe("acknowledged");
      expect((await advance(msg.reference))!.state).toBe("accepted");
      expect((await advance(msg.reference))!.state).toBe("settled");
      expect((await advance(msg.reference))!.state).toBe("settled"); // terminal
      const final = getMessage(msg.reference)!;
      expect(final.stateHistory.map((h) => h.state)).toEqual([
        "received",
        "acknowledged",
        "accepted",
        "settled",
      ]);
    });

    it("supports rejection and stops lifecycle progression", async () => {
      const msg = recordDispatch({ messageType: "MT202", payload: "MT202 payload" });
      const rejected = rejectMessage(msg.reference, "bad coordinates")!;
      expect(rejected.state).toBe("rejected");
      const afterAdvance = await advance(msg.reference);
      expect(afterAdvance!.state).toBe("rejected");
    });

    it("listMessages filters by planId", () => {
      recordDispatch({ messageType: "MT760", payload: "a", planId: "plan-a" });
      recordDispatch({ messageType: "MT760", payload: "b", planId: "plan-b" });
      recordDispatch({ messageType: "MT760", payload: "c", planId: "plan-a" });
      expect(listMessages().length).toBe(3);
      expect(listMessages({ planId: "plan-a" }).length).toBe(2);
    });
  });

  describe("signature", () => {
    it("produces a stable 64-char hex HMAC", () => {
      const sig = finSignature("hello");
      expect(sig).toMatch(/^[0-9a-f]{64}$/);
      expect(finSignature("hello")).toBe(sig);
      expect(finSignature("world")).not.toBe(sig);
    });
  });

  describe("HTTP router", () => {
    const app = express();
    app.use("/fin", buildSandboxRouter());

    beforeEach(() => resetSandboxForTests());

    it("POST /fin/dispatch returns 202 + reference", async () => {
      const resp = await request(app)
        .post("/fin/dispatch")
        .send({ messageType: "MT760", payload: "mt760", planId: "plan-x" })
        .expect(202);
      expect(resp.body.reference).toMatch(/^FIN-/);
      expect(resp.body.state).toBe("received");
    });

    it("POST /fin/dispatch 400s on missing payload", async () => {
      await request(app)
        .post("/fin/dispatch")
        .send({ messageType: "MT760" })
        .expect(400);
    });

    it("POST /fin/advance/:ref walks through lifecycle", async () => {
      const d = await request(app)
        .post("/fin/dispatch")
        .send({ messageType: "pacs.009", payload: "<pacs.009/>" })
        .expect(202);
      const ref = d.body.reference;
      const a1 = await request(app).post(`/fin/advance/${ref}`).expect(200);
      expect(a1.body.state).toBe("acknowledged");
      const a2 = await request(app).post(`/fin/advance/${ref}`).expect(200);
      expect(a2.body.state).toBe("accepted");
      const a3 = await request(app).post(`/fin/advance/${ref}`).expect(200);
      expect(a3.body.state).toBe("settled");
    });

    it("GET /fin/messages?planId=... filters", async () => {
      await request(app)
        .post("/fin/dispatch")
        .send({ messageType: "MT760", payload: "a", planId: "p1" });
      await request(app)
        .post("/fin/dispatch")
        .send({ messageType: "MT760", payload: "b", planId: "p2" });
      const r = await request(app).get("/fin/messages?planId=p1").expect(200);
      expect(r.body.messages).toHaveLength(1);
      expect(r.body.messages[0].planId).toBe("p1");
    });

    it("GET /fin/messages/:ref returns 404 for unknown", async () => {
      await request(app).get("/fin/messages/FIN-UNKNOWN").expect(404);
    });
  });

  describe("client", () => {
    beforeEach(() => resetSandboxForTests());

    it("createInProcessFinLinkClient dispatches and reads back", async () => {
      const client = await createInProcessFinLinkClient();
      const ack = await client.dispatch({
        messageType: "MT760",
        payload: "mt760",
        planId: "plan-ip",
      });
      expect(ack.reference).toMatch(/^FIN-/);
      const msg = await client.getMessage(ack.reference);
      expect(msg?.planId).toBe("plan-ip");
    });

    it("createHttpFinLinkClient hits the live router", async () => {
      const app = express();
      app.use("/fin", buildSandboxRouter());
      const server = app.listen(0);
      try {
        const addr = server.address();
        const port = typeof addr === "object" && addr ? addr.port : 0;
        const client = createHttpFinLinkClient(`http://127.0.0.1:${port}/fin`);
        const ack = await client.dispatch({
          messageType: "pacs.009",
          payload: "<pacs.009/>",
          planId: "plan-http",
        });
        expect(ack.reference).toMatch(/^FIN-/);
        const msg = await client.getMessage(ack.reference);
        expect(msg?.messageType).toBe("pacs.009");
        const missing = await client.getMessage("FIN-DOES-NOT-EXIST");
        expect(missing).toBeNull();
      } finally {
        server.close();
      }
    });
  });
});