import { describe, it, expect, beforeEach, beforeAll, vi } from "vitest";
import { getRecentErrorLogs, clearLogs, initLogCapture } from "./logService";

beforeAll(() => {
  // Patch console.* so addEntry runs. Idempotent.
  initLogCapture();
});

describe("getRecentErrorLogs", () => {
  beforeEach(() => {
    // Reset the in-memory buffer. clearLogs also clears sessionStorage
    // which jsdom provides in vitest.
    clearLogs();
  });

  it("returns an empty string when the log buffer is empty", () => {
    expect(getRecentErrorLogs(5)).toBe("");
  });

  it("returns an empty string when n <= 0", () => {
    console.error("boom");
    expect(getRecentErrorLogs(0)).toBe("");
    expect(getRecentErrorLogs(-3)).toBe("");
  });

  it("filters out info-level entries", () => {
    // Freeze time so the ISO prefix is predictable
    vi.setSystemTime(new Date("2026-04-17T15:00:00.000Z"));
    console.log("just chatter");
    console.warn("low fuel");
    console.error("engine out");

    const out = getRecentErrorLogs(10);
    expect(out).not.toContain("chatter");
    expect(out).toContain("WARN: low fuel");
    expect(out).toContain("ERROR: engine out");
    vi.useRealTimers();
  });

  it("keeps only the last N non-info entries in order", () => {
    for (let i = 0; i < 5; i++) console.warn(`w${i}`);
    const out = getRecentErrorLogs(2);
    const lines = out.split("\n");
    expect(lines).toHaveLength(2);
    expect(lines[0]).toContain("w3");
    expect(lines[1]).toContain("w4");
  });

  it("formats each line as `[ISO] LEVEL: message`", () => {
    vi.setSystemTime(new Date("2026-04-17T15:23:45.000Z"));
    console.error("export failed");
    const out = getRecentErrorLogs(1);
    expect(out).toMatch(/^\[2026-04-17T15:23:45\.000Z\] ERROR: export failed$/);
    vi.useRealTimers();
  });
});