import { describe, it, expect } from "vitest";
import {
  calculateSMA,
  calculateEMA,
  calculateRSI,
  calculateMACD,
} from "../../utils/indicators";

describe("calculateSMA", () => {
  it("returns 0 when prices length < period", () => {
    expect(calculateSMA([1, 2], 5)).toBe(0);
  });

  it("calculates simple moving average correctly", () => {
    expect(calculateSMA([1, 2, 3, 4, 5], 5)).toBe(3);
  });
});

describe("calculateEMA", () => {
  it("returns 0 when prices length < period", () => {
    expect(calculateEMA([1, 2], 5)).toBe(0);
  });

  it("calculates exponential moving average", () => {
    const prices = [10, 11, 12, 13, 14, 15];
    const result = calculateEMA(prices, 3);
    expect(result).toBeCloseTo(14.125, 2);
  });
});

describe("calculateRSI", () => {
  it("returns 0 when prices length < period + 1", () => {
    expect(calculateRSI([1, 2, 3], 5)).toBe(0);
  });

  it("calculates relative strength index", () => {
    const prices = [100, 102, 101, 105, 107, 110, 108, 115, 120, 119, 121];
    const result = calculateRSI(prices, 5);
    expect(result).toBeGreaterThan(50);
    expect(result).toBeLessThan(100);
  });
});

describe("calculateMACD", () => {
  it("returns 0 when prices length < slowPeriod", () => {
    expect(calculateMACD([1, 2, 3], 12, 26, 9)).toBe(0);
  });

  it("calculates MACD line", () => {
    const prices = Array.from({ length: 30 }, (_, i) => 100 + i * 0.5);
    const result = calculateMACD(prices);
    expect(result).toBeCloseTo(-0.96, 2);
  });
});