const { describe, test, expect, beforeEach } = require("@jest/globals");

// Mock config
jest.mock("../../config", () => ({
  app: {
    delayMinutes: 5,
  },
}));

// Mock logger
jest.mock("../../lib/logger", () => ({
  rateLimitPause: jest.fn(),
}));

const rateLimiter = require("../../lib/rateLimiter");

describe("RateLimiter", () => {
  beforeEach(() => {
    jest.clearAllMocks();
    rateLimiter.reset();
  });

  describe("getRandomDelay", () => {
    test("should return delay within expected range", () => {
      const delay = rateLimiter.getRandomDelay();

      // Base delay is 5 minutes = 300,000ms
      // With 20% variance and jitter, expect roughly 240,000 to 390,000ms
      expect(delay).toBeGreaterThan(200000);
      expect(delay).toBeLessThan(400000);
    });

    test("should return different delays each time (due to randomization)", () => {
      const delay1 = rateLimiter.getRandomDelay();
      const delay2 = rateLimiter.getRandomDelay();
      const delay3 = rateLimiter.getRandomDelay();

      // Extremely unlikely to be identical due to randomization
      expect(delay1).not.toBe(delay2);
      expect(delay2).not.toBe(delay3);
    });
  });

  describe("shouldPause", () => {
    test("should not pause initially", () => {
      expect(rateLimiter.shouldPause()).toBe(false);
    });

    test("should pause after sending many emails in short time", () => {
      // Simulate sending 20 emails in 1 hour (exceeds 15/hour limit)
      rateLimiter.sentCount = 20;
      rateLimiter.startTime = Date.now() - 60 * 60 * 1000; // 1 hour ago

      expect(rateLimiter.shouldPause()).toBe(true);
    });

    test("should pause every 50 emails", () => {
      rateLimiter.sentCount = 50;
      expect(rateLimiter.shouldPause()).toBe(true);

      rateLimiter.sentCount = 100;
      expect(rateLimiter.shouldPause()).toBe(true);
    });

    test("should not pause if under rate limit", () => {
      // Simulate sending 10 emails in 1 hour (under 15/hour limit)
      rateLimiter.sentCount = 10;
      rateLimiter.startTime = Date.now() - 60 * 60 * 1000; // 1 hour ago

      expect(rateLimiter.shouldPause()).toBe(false);
    });
  });

  describe("getPauseDuration", () => {
    test("should return pause duration around 30 minutes", () => {
      const duration = rateLimiter.getPauseDuration();

      // Base pause is 30 minutes = 1,800,000ms
      // With randomization, expect 30-40 minutes
      expect(duration).toBeGreaterThan(30 * 60 * 1000);
      expect(duration).toBeLessThan(40 * 60 * 1000);
    });
  });

  describe("getNextSendDelay", () => {
    test("should increment sent count", async () => {
      const initialCount = rateLimiter.sentCount;
      await rateLimiter.getNextSendDelay();
      expect(rateLimiter.sentCount).toBe(initialCount + 1);
    });

    test("should return pause duration when should pause", async () => {
      // Force a pause condition
      rateLimiter.sentCount = 49; // Next increment will trigger pause at 50

      const delay = await rateLimiter.getNextSendDelay();

      // Should be a long pause, not normal delay
      expect(delay).toBeGreaterThan(30 * 60 * 1000); // More than 30 minutes
    });

    test("should return normal delay when not pausing", async () => {
      rateLimiter.sentCount = 5; // Low count, won't trigger pause

      const delay = await rateLimiter.getNextSendDelay();

      // Should be normal delay (around 5 minutes with variance)
      expect(delay).toBeGreaterThan(200000);
      expect(delay).toBeLessThan(400000);
    });
  });

  describe("formatDelay", () => {
    test("should format milliseconds to readable time", () => {
      expect(rateLimiter.formatDelay(60000)).toBe("1m 0s");
      expect(rateLimiter.formatDelay(90000)).toBe("1m 30s");
      expect(rateLimiter.formatDelay(125000)).toBe("2m 5s");
      expect(rateLimiter.formatDelay(3661000)).toBe("61m 1s");
    });
  });

  describe("getStats", () => {
    test("should return correct statistics", () => {
      rateLimiter.sentCount = 10;
      rateLimiter.startTime = Date.now() - 60 * 60 * 1000; // 1 hour ago

      const stats = rateLimiter.getStats();

      expect(stats.sentCount).toBe(10);
      expect(stats.runtime).toBe(60); // 60 minutes
      expect(stats.averageRate).toBe("10.0"); // 10 emails per hour
      expect(stats.nextDelay).toMatch(/^\d+m \d+s$/); // Format like "5m 23s"
    });

    test("should handle zero runtime gracefully", () => {
      rateLimiter.sentCount = 5;
      rateLimiter.startTime = Date.now(); // Just started

      const stats = rateLimiter.getStats();

      expect(stats.sentCount).toBe(5);
      expect(stats.runtime).toBe(0);
      // Average rate should be very high for instant runtime
      expect(parseFloat(stats.averageRate)).toBeGreaterThan(1000);
    });
  });

  describe("reset", () => {
    test("should reset all counters", () => {
      rateLimiter.sentCount = 10;
      rateLimiter.lastSentTime = Date.now() - 60000;

      rateLimiter.reset();

      expect(rateLimiter.sentCount).toBe(0);
      expect(rateLimiter.lastSentTime).toBeNull();
      expect(rateLimiter.startTime).toBeCloseTo(Date.now(), -1); // Within 10ms
    });
  });
});