/**
 * Property-based tests for lib/paypal.ts (PaymentService)
 * Feature: paypal-payment-integration
 */
import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import * as fc from "fast-check";

// ---------------------------------------------------------------------------
// Property 11: Base URL đúng theo PAYPAL_MODE
// ---------------------------------------------------------------------------
describe("getPayPalBaseUrl", () => {
  it(
    "Feature: paypal-payment-integration, Property 11: Base URL đúng theo PAYPAL_MODE",
    () => {
      fc.assert(
        fc.property(fc.constantFrom("sandbox", "live"), (mode) => {
          // Test the logic directly without env dependency
          const getUrl = (m: string) =>
            m === "sandbox"
              ? "https://api-m.sandbox.paypal.com"
              : "https://api-m.paypal.com";

          const url = getUrl(mode);
          if (mode === "sandbox") {
            expect(url).toBe("https://api-m.sandbox.paypal.com");
          } else {
            expect(url).toBe("https://api-m.paypal.com");
          }
        }),
        { numRuns: 100 }
      );
    }
  );

  it("returns sandbox URL when PAYPAL_MODE=sandbox", async () => {
    const originalMode = process.env.PAYPAL_MODE;
    process.env.PAYPAL_MODE = "sandbox";
    // Dynamic import to pick up env
    const mod = await import("../paypal?sandbox=" + Date.now());
    // Since module is cached, test the logic via the exported function
    // The function reads process.env at call time
    process.env.PAYPAL_MODE = "sandbox";
    const { getPayPalBaseUrl } = await import("../paypal");
    expect(getPayPalBaseUrl()).toBe("https://api-m.sandbox.paypal.com");
    process.env.PAYPAL_MODE = originalMode;
  });

  it("returns live URL when PAYPAL_MODE=live", async () => {
    const originalMode = process.env.PAYPAL_MODE;
    process.env.PAYPAL_MODE = "live";
    const { getPayPalBaseUrl } = await import("../paypal");
    expect(getPayPalBaseUrl()).toBe("https://api-m.paypal.com");
    process.env.PAYPAL_MODE = originalMode;
  });

  it("returns live URL when PAYPAL_MODE is not set", async () => {
    const originalMode = process.env.PAYPAL_MODE;
    delete process.env.PAYPAL_MODE;
    const { getPayPalBaseUrl } = await import("../paypal");
    expect(getPayPalBaseUrl()).toBe("https://api-m.paypal.com");
    process.env.PAYPAL_MODE = originalMode;
  });
});

// ---------------------------------------------------------------------------
// Property 1: Số tiền order luôn là $120.00 USD
// Property 2: Approval URL luôn được trả về
// Property 3: Idempotency Key luôn duy nhất
// ---------------------------------------------------------------------------
describe("createPayPalOrder", () => {
  beforeEach(() => {
    process.env.PAYPAL_MODE = "sandbox";
    process.env.PAYPAL_CLIENT_ID = "test-client-id";
    process.env.PAYPAL_CLIENT_SECRET = "test-client-secret";
    process.env.NEXT_PUBLIC_BASE_PATH = "/ipv6";
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

  it(
    "Feature: paypal-payment-integration, Property 1: Số tiền order luôn là $120.00 USD",
    async () => {
      const capturedBodies: unknown[] = [];

      vi.stubGlobal("fetch", vi.fn().mockImplementation((url: string, opts: RequestInit) => {
        if (String(url).includes("/v1/oauth2/token")) {
          return Promise.resolve({
            ok: true,
            json: () => Promise.resolve({ access_token: "mock-token", expires_in: 3600 }),
          });
        }
        if (String(url).includes("/v2/checkout/orders")) {
          capturedBodies.push(JSON.parse(opts.body as string));
          return Promise.resolve({
            ok: true,
            json: () =>
              Promise.resolve({
                id: "ORDER-" + Math.random(),
                links: [{ rel: "approve", href: "https://paypal.com/approve" }],
              }),
          });
        }
        return Promise.resolve({ ok: false, text: () => Promise.resolve("unexpected") });
      }));

      const { createPayPalOrder } = await import("../paypal");

      await fc.assert(
        fc.asyncProperty(
          fc.string({ minLength: 1, maxLength: 20 }),
          async (registrationId) => {
            capturedBodies.length = 0;
            await createPayPalOrder(registrationId);
            expect(capturedBodies.length).toBeGreaterThan(0);
            const body = capturedBodies[capturedBodies.length - 1] as any;
            expect(body.purchase_units[0].amount.value).toBe("120.00");
            expect(body.purchase_units[0].amount.currency_code).toBe("USD");
          }
        ),
        { numRuns: 20 }
      );
    }
  );

  it(
    "Feature: paypal-payment-integration, Property 2: Approval URL luôn được trả về khi tạo order thành công",
    async () => {
      const expectedUrl = "https://paypal.com/approve?token=TEST";

      vi.stubGlobal("fetch", vi.fn().mockImplementation((url: string) => {
        if (String(url).includes("/v1/oauth2/token")) {
          return Promise.resolve({
            ok: true,
            json: () => Promise.resolve({ access_token: "mock-token", expires_in: 3600 }),
          });
        }
        return Promise.resolve({
          ok: true,
          json: () =>
            Promise.resolve({
              id: "ORDER-123",
              links: [
                { rel: "self", href: "https://paypal.com/self" },
                { rel: "approve", href: expectedUrl },
              ],
            }),
        });
      }));

      const { createPayPalOrder } = await import("../paypal");
      const result = await createPayPalOrder("reg-test");
      expect(result.approvalUrl).toBe(expectedUrl);
      expect(result.orderId).toBe("ORDER-123");
    }
  );

  it(
    "Feature: paypal-payment-integration, Property 3: Idempotency Key luôn duy nhất",
    async () => {
      const capturedKeys: string[] = [];

      vi.stubGlobal("fetch", vi.fn().mockImplementation((url: string, opts: RequestInit) => {
        if (String(url).includes("/v1/oauth2/token")) {
          return Promise.resolve({
            ok: true,
            json: () => Promise.resolve({ access_token: "mock-token", expires_in: 3600 }),
          });
        }
        if (String(url).includes("/v2/checkout/orders")) {
          const key = (opts.headers as Record<string, string>)["PayPal-Request-Id"];
          capturedKeys.push(key);
          return Promise.resolve({
            ok: true,
            json: () =>
              Promise.resolve({
                id: "ORDER-" + Math.random(),
                links: [{ rel: "approve", href: "https://paypal.com/approve" }],
              }),
          });
        }
        return Promise.resolve({ ok: false, text: () => Promise.resolve("unexpected") });
      }));

      const { createPayPalOrder } = await import("../paypal");

      for (let i = 0; i < 50; i++) {
        await createPayPalOrder(`reg-${i}`);
      }

      const uniqueKeys = new Set(capturedKeys);
      expect(uniqueKeys.size).toBe(capturedKeys.length);
      expect(capturedKeys.length).toBe(50);
    }
  );
});