comparaison/e2e/compare.spec.ts

import { test, expect } from "@playwright/test";
import { resolveUrl, getSessionCookie, parseSSEStream, lastSSEOfType } from "./helpers";

/**
 * E2E tests for the /api/compare endpoint.
 * Covers: request validation, full SSE flow, success/failure states, and DB persistence.
 */
test.describe("Compare API", () => {
  let cookie: string;

  test.beforeEach(async ({ page }) => {
    cookie = await getSessionCookie(page);
  });

  // ─── Input Validation ────────────────────────────────────────────────────

  test("1. Rejects fewer than 2 items", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { items: ["React"] },
      headers: { "Content-Type": "application/json", Cookie: cookie },
    });
    expect(res.status()).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/2 items|at least/i);
  });

  test("2. Rejects more than 10 items", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { items: Array.from({ length: 11 }, (_, i) => `Item${i}`) },
      headers: { "Content-Type": "application/json", Cookie: cookie },
    });
    expect(res.status()).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/10|maximum/i);
  });

  test("3. Rejects empty item names", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { items: ["React", "  ", "Vue"] },
      headers: { "Content-Type": "application/json", Cookie: cookie },
    });
    expect(res.status()).toBe(400);
    const body = await res.json();
    expect(body.error).toMatch(/empty/i);
  });

  test("4. Rejects unauthenticated requests", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { items: ["React", "Vue"] },
      headers: { "Content-Type": "application/json" },
    });
    expect(res.status()).toBe(401);
  });

  // ─── Happy Path ──────────────────────────────────────────────────────────

  test("5. Compare returns SSE stream with progress events", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { query: "Python vs JavaScript", items: ["Python", "JavaScript"] },
      headers: {
        "Content-Type": "application/json",
        Cookie: cookie,
        Accept: "text/event-stream",
      },
    });

    expect(res.status()).toBe(200);
    expect(res.headers()["content-type"]).toContain("text/event-stream");

    const body = await res.body();
    if (!body) { test.skip(); return; }
    const bodyStr = Buffer.from(body).toString("utf-8");
    const events = await parseSSEStream(bodyStr);

    // Should have at least one progress event
    const progressEvents = events.filter((e) => e.status !== undefined);
    expect(progressEvents.length).toBeGreaterThan(0);
  });

  test("6. Full compare flow completes successfully", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { query: "React vs Vue", items: ["React", "Vue"] },
      headers: {
        "Content-Type": "application/json",
        Cookie: cookie,
        Accept: "text/event-stream",
      },
      timeout: 120_000,
    });

    expect(res.status()).toBe(200);
    const body = Buffer.from((await res.body()) ?? []).toString("utf-8");
    const events = await parseSSEStream(body);

    // Must have a final status
    const finalProgress = lastSSEOfType(events, "progress");
    expect(finalProgress).toBeDefined();
    expect(["completed", "failed"]).toContain(finalProgress!.status);

    if (finalProgress!.status === "completed") {
      const doneEvent = lastSSEOfType(events, "done") as Record<string, unknown> | undefined;
      expect(doneEvent).toBeDefined();

      const doneData = doneEvent!.done as Record<string, unknown>;
      expect(doneData).toHaveProperty("id");
      expect(doneData).toHaveProperty("slug");
      expect((doneData.data as Record<string, unknown>)).toHaveProperty("summary");
      expect((doneData.data as Record<string, unknown>)).toHaveProperty("items");
    }
  });

  test("7. Comparison is persisted to DB after completion", async ({ page }) => {
    // Run a comparison
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: { query: "Rust vs Go", items: ["Rust", "Go"] },
      headers: { "Content-Type": "application/json", Cookie: cookie, Accept: "text/event-stream" },
      timeout: 120_000,
    });

    expect(res.status()).toBe(200);
    const body = Buffer.from((await res.body()) ?? []).toString("utf-8");
    const events = await parseSSEStream(body);
    const doneEvent = lastSSEOfType(events, "done") as Record<string, unknown> | undefined;
    if (!doneEvent) { test.skip(); return; }

    const { slug } = doneEvent.done as { slug: string };
    expect(slug).toBeTruthy();

    // Fetch it back
    const getRes = await page.request.get(resolveUrl(`/api/comparisons/${slug}`), {
      headers: { Cookie: cookie },
    });
    expect(getRes.status()).toBe(200);
    const comparison = await getRes.json();
    expect(comparison.slug).toBe(slug);
    expect(comparison.status).toBe("completed");
  });

  test("8. Compare with custom dimensions", async ({ page }) => {
    const res = await page.request.post(resolveUrl("/api/compare"), {
      data: {
        query: "React vs Angular",
        items: ["React", "Angular"],
        dimensions: ["Performance", "Learning Curve", "Ecosystem"],
      },
      headers: {
        "Content-Type": "application/json",
        Cookie: cookie,
        Accept: "text/event-stream",
      },
      timeout: 120_000,
    });

    expect(res.status()).toBe(200);
    const body = Buffer.from((await res.body()) ?? []).toString("utf-8");
    const events = await parseSSEStream(body);
    const finalProgress = lastSSEOfType(events, "progress");
    expect(finalProgress).toBeDefined();
    expect(["completed", "failed"]).toContain(finalProgress!.status);
  });
});