docfast/src/__tests__/billing-branch-coverage.test.ts

import { describe, it, expect, vi, beforeEach } from "vitest";
import express from "express";
import request from "supertest";

// Mock Stripe before importing billing router
vi.mock("stripe", () => {
  const mockStripe = {
    checkout: {
      sessions: {
        create: vi.fn(),
        retrieve: vi.fn(),
      },
    },
    webhooks: {
      constructEvent: vi.fn(),
    },
    products: {
      search: vi.fn(),
      create: vi.fn(),
    },
    prices: {
      list: vi.fn(),
      create: vi.fn(),
    },
    subscriptions: {
      retrieve: vi.fn(),
    },
  };
  return { default: vi.fn(function() { return mockStripe; }), __mockStripe: mockStripe };
});

let app: express.Express;
let mockStripe: any;

beforeEach(async () => {
  vi.clearAllMocks();
  vi.resetModules();

  process.env.STRIPE_SECRET_KEY = "sk_test_fake";
  process.env.STRIPE_WEBHOOK_SECRET = "whsec_test_fake";

  const stripeMod = await import("stripe");
  mockStripe = (stripeMod as any).__mockStripe;

  // Default: product search returns existing product+price
  mockStripe.products.search.mockResolvedValue({ data: [{ id: "prod_TygeG8tQPtEAdE" }] });
  mockStripe.prices.list.mockResolvedValue({ data: [{ id: "price_123" }] });

  const { createProKey, findKeyByCustomerId, downgradeByCustomer, updateEmailByCustomer } = await import("../services/keys.js");
  vi.mocked(createProKey).mockResolvedValue({ key: "pro-key-123", tier: "pro", email: "test@test.com", createdAt: new Date().toISOString() } as any);
  vi.mocked(findKeyByCustomerId).mockResolvedValue(null);
  vi.mocked(downgradeByCustomer).mockResolvedValue(undefined as any);
  vi.mocked(updateEmailByCustomer).mockResolvedValue(true as any);

  const { billingRouter } = await import("../routes/billing.js");
  app = express();
  app.use("/v1/billing/webhook", express.raw({ type: "application/json" }));
  app.use(express.json());
  app.use("/v1/billing", billingRouter);
});

describe("Billing Branch Coverage", () => {
  describe("isDocFastSubscription - expanded product object (lines 63-67)", () => {
    it("should handle expanded product object instead of string", async () => {
      // Test the branch where price.product is an expanded Stripe.Product object
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "checkout.session.completed",
        data: {
          object: {
            id: "cs_expanded_product",
            customer: "cus_expanded",
            customer_details: { email: "expanded@test.com" },
          },
        },
      });

      // Mock: line_items has price.product as an object (not a string)
      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_expanded_product",
        line_items: {
          data: [
            { 
              price: { 
                product: { id: "prod_TygeG8tQPtEAdE" }  // Expanded object, not string
              } 
            }
          ],
        },
      });

      const { createProKey } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "checkout.session.completed" }));

      expect(res.status).toBe(200);
      expect(createProKey).toHaveBeenCalledWith("expanded@test.com", "cus_expanded");
    });

    it("should handle expanded product object in subscription.deleted webhook", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.subscription.deleted",
        data: {
          object: { id: "sub_expanded", customer: "cus_expanded_del" },
        },
      });

      // subscription.retrieve returns expanded product object
      mockStripe.subscriptions.retrieve.mockResolvedValue({
        items: { 
          data: [
            { 
              price: { 
                product: { id: "prod_TygeG8tQPtEAdE" }  // Expanded object
              } 
            }
          ] 
        },
      });

      const { downgradeByCustomer } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.subscription.deleted" }));

      expect(res.status).toBe(200);
      expect(downgradeByCustomer).toHaveBeenCalledWith("cus_expanded_del");
    });
  });

  describe("isDocFastSubscription - error handling (lines 70-71)", () => {
    it("should return false when subscriptions.retrieve throws an error", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.subscription.deleted",
        data: {
          object: { id: "sub_error", customer: "cus_error" },
        },
      });

      // Mock: subscriptions.retrieve throws an error
      mockStripe.subscriptions.retrieve.mockRejectedValue(new Error("Stripe API error"));

      const { downgradeByCustomer } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.subscription.deleted" }));

      // Should succeed but NOT downgrade (because isDocFastSubscription returns false on error)
      expect(res.status).toBe(200);
      expect(downgradeByCustomer).not.toHaveBeenCalled();
    });

    it("should return false when subscriptions.retrieve throws in subscription.updated", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.subscription.updated",
        data: {
          object: { 
            id: "sub_update_error", 
            customer: "cus_update_error",
            status: "canceled",
            cancel_at_period_end: false,
          },
        },
      });

      mockStripe.subscriptions.retrieve.mockRejectedValue(new Error("Network timeout"));

      const { downgradeByCustomer } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.subscription.updated" }));

      expect(res.status).toBe(200);
      expect(downgradeByCustomer).not.toHaveBeenCalled();
    });
  });

  describe("getOrCreateProPrice - no existing product (lines 316-331)", () => {
    it("should create new product and price when none exists", async () => {
      // Mock: no existing product found
      mockStripe.products.search.mockResolvedValue({ data: [] });
      
      // Mock: product.create returns new product
      mockStripe.products.create.mockResolvedValue({ id: "prod_new_123" });
      
      // Mock: price.create returns new price
      mockStripe.prices.create.mockResolvedValue({ id: "price_new_456" });

      // Mock: checkout.sessions.create succeeds
      mockStripe.checkout.sessions.create.mockResolvedValue({ 
        id: "cs_new", 
        url: "https://checkout.stripe.com/pay/cs_new" 
      });

      const res = await request(app)
        .post("/v1/billing/checkout")
        .send({});

      expect(res.status).toBe(200);
      expect(mockStripe.products.create).toHaveBeenCalledWith({
        name: "DocFast Pro",
        description: "5,000 PDFs / month via API. HTML, Markdown, and URL to PDF.",
      });
      expect(mockStripe.prices.create).toHaveBeenCalledWith({
        product: "prod_new_123",
        unit_amount: 900,
        currency: "eur",
        recurring: { interval: "month" },
      });
      expect(mockStripe.checkout.sessions.create).toHaveBeenCalledWith(
        expect.objectContaining({
          line_items: [{ price: "price_new_456", quantity: 1 }],
        })
      );
    });

    it("should create new price when product exists but has no active prices", async () => {
      // Mock: product exists
      mockStripe.products.search.mockResolvedValue({ data: [{ id: "prod_existing" }] });
      
      // Mock: no active prices found
      mockStripe.prices.list.mockResolvedValue({ data: [] });
      
      // Mock: price.create returns new price
      mockStripe.prices.create.mockResolvedValue({ id: "price_new_789" });

      // Mock: checkout.sessions.create succeeds
      mockStripe.checkout.sessions.create.mockResolvedValue({ 
        id: "cs_existing", 
        url: "https://checkout.stripe.com/pay/cs_existing" 
      });

      const res = await request(app)
        .post("/v1/billing/checkout")
        .send({});

      expect(res.status).toBe(200);
      expect(mockStripe.products.create).not.toHaveBeenCalled(); // Product exists, don't create
      expect(mockStripe.prices.create).toHaveBeenCalledWith({
        product: "prod_existing",
        unit_amount: 900,
        currency: "eur",
        recurring: { interval: "month" },
      });
      expect(mockStripe.checkout.sessions.create).toHaveBeenCalledWith(
        expect.objectContaining({
          line_items: [{ price: "price_new_789", quantity: 1 }],
        })
      );
    });
  });

  describe("Success route - customerId branch (line 163)", () => {
    it("should return 400 when session.customer is null (not a string)", async () => {
      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_null_customer",
        customer: null,  // Explicitly null, not falsy string
        customer_details: { email: "test@example.com" },
      });

      const res = await request(app).get("/v1/billing/success?session_id=cs_null_customer");
      
      expect(res.status).toBe(400);
      expect(res.body.error).toContain("No customer found");
    });

    it("should return 400 when customer is empty string", async () => {
      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_empty_customer",
        customer: "",  // Empty string is falsy
        customer_details: { email: "test@example.com" },
      });

      const res = await request(app).get("/v1/billing/success?session_id=cs_empty_customer");
      
      expect(res.status).toBe(400);
      expect(res.body.error).toContain("No customer found");
    });

    it("should return 400 when customer is undefined", async () => {
      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_undef_customer",
        customer: undefined,
        customer_details: { email: "test@example.com" },
      });

      const res = await request(app).get("/v1/billing/success?session_id=cs_undef_customer");
      
      expect(res.status).toBe(400);
      expect(res.body.error).toContain("No customer found");
    });
  });

  describe("Webhook checkout.session.completed - hasDocfastProduct branch (line 223)", () => {
    it("should skip webhook event when line_items is undefined", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "checkout.session.completed",
        data: {
          object: {
            id: "cs_no_items",
            customer: "cus_no_items",
            customer_details: { email: "test@example.com" },
          },
        },
      });

      // Mock: line_items is undefined
      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_no_items",
        line_items: undefined,
      });

      const { createProKey } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "checkout.session.completed" }));

      expect(res.status).toBe(200);
      expect(createProKey).not.toHaveBeenCalled();
    });

    it("should skip webhook event when line_items.data is empty", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "checkout.session.completed",
        data: {
          object: {
            id: "cs_empty_items",
            customer: "cus_empty_items",
            customer_details: { email: "test@example.com" },
          },
        },
      });

      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_empty_items",
        line_items: { data: [] },  // Empty array - no items
      });

      const { createProKey } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "checkout.session.completed" }));

      expect(res.status).toBe(200);
      expect(createProKey).not.toHaveBeenCalled();
    });

    it("should skip webhook event when price is null", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "checkout.session.completed",
        data: {
          object: {
            id: "cs_null_price",
            customer: "cus_null_price",
            customer_details: { email: "test@example.com" },
          },
        },
      });

      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_null_price",
        line_items: {
          data: [{ price: null }],  // Null price
        },
      });

      const { createProKey } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "checkout.session.completed" }));

      expect(res.status).toBe(200);
      expect(createProKey).not.toHaveBeenCalled();
    });

    it("should skip webhook event when product is null", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "checkout.session.completed",
        data: {
          object: {
            id: "cs_null_product",
            customer: "cus_null_product",
            customer_details: { email: "test@example.com" },
          },
        },
      });

      mockStripe.checkout.sessions.retrieve.mockResolvedValue({
        id: "cs_null_product",
        line_items: {
          data: [{ price: { product: null } }],  // Null product
        },
      });

      const { createProKey } = await import("../services/keys.js");
      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "checkout.session.completed" }));

      expect(res.status).toBe(200);
      expect(createProKey).not.toHaveBeenCalled();
    });
  });

  describe("Webhook customer.updated event (line 284-303)", () => {
    it("should sync email when both customerId and newEmail exist", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.updated",
        data: {
          object: {
            id: "cus_email_update",
            email: "newemail@example.com",
          },
        },
      });

      const { updateEmailByCustomer } = await import("../services/keys.js");
      vi.mocked(updateEmailByCustomer).mockResolvedValue(true);

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.updated" }));

      expect(res.status).toBe(200);
      expect(updateEmailByCustomer).toHaveBeenCalledWith("cus_email_update", "newemail@example.com");
    });

    it("should not sync email when customerId is missing", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.updated",
        data: {
          object: {
            id: undefined,  // Missing customerId
            email: "newemail@example.com",
          },
        },
      });

      const { updateEmailByCustomer } = await import("../services/keys.js");

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.updated" }));

      expect(res.status).toBe(200);
      expect(updateEmailByCustomer).not.toHaveBeenCalled();
    });

    it("should not sync email when email is missing", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.updated",
        data: {
          object: {
            id: "cus_no_email",
            email: null,  // Missing email
          },
        },
      });

      const { updateEmailByCustomer } = await import("../services/keys.js");

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.updated" }));

      expect(res.status).toBe(200);
      expect(updateEmailByCustomer).not.toHaveBeenCalled();
    });

    it("should not sync email when email is undefined", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.updated",
        data: {
          object: {
            id: "cus_no_email_2",
            email: undefined,  // Undefined email
          },
        },
      });

      const { updateEmailByCustomer } = await import("../services/keys.js");

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.updated" }));

      expect(res.status).toBe(200);
      expect(updateEmailByCustomer).not.toHaveBeenCalled();
    });

    it("should log when email update returns false", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "customer.updated",
        data: {
          object: {
            id: "cus_no_update",
            email: "newemail@example.com",
          },
        },
      });

      const { updateEmailByCustomer } = await import("../services/keys.js");
      vi.mocked(updateEmailByCustomer).mockResolvedValue(false);  // Update returns false

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "customer.updated" }));

      expect(res.status).toBe(200);
      expect(updateEmailByCustomer).toHaveBeenCalledWith("cus_no_update", "newemail@example.com");
      // The if (updated) branch should not be executed when false
    });
  });

  describe("Webhook default case", () => {
    it("should handle unknown webhook event type", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "unknown.event.type",
        data: { object: {} },
      });

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "unknown.event.type" }));

      expect(res.status).toBe(200);
      expect(res.body.received).toBe(true);
    });

    it("should handle payment_intent.succeeded webhook event", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "payment_intent.succeeded",
        data: { object: {} },
      });

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "payment_intent.succeeded" }));

      expect(res.status).toBe(200);
      expect(res.body.received).toBe(true);
    });

    it("should handle invoice.payment_succeeded webhook event", async () => {
      mockStripe.webhooks.constructEvent.mockReturnValue({
        type: "invoice.payment_succeeded",
        data: { object: {} },
      });

      const res = await request(app)
        .post("/v1/billing/webhook")
        .set("content-type", "application/json")
        .set("stripe-signature", "valid_sig")
        .send(JSON.stringify({ type: "invoice.payment_succeeded" }));

      expect(res.status).toBe(200);
      expect(res.body.received).toBe(true);
    });
  });
});