import { describe, it, expect } from "vitest";
import {
  base91ToNumber,
  knotsToKmh,
  kmhToKnots,
  feetToMeters,
  metersToFeet,
  celsiusToFahrenheit,
  fahrenheitToCelsius,
} from "../src/parser";

describe("parser utilities", () => {
  describe("base91ToNumber", () => {
    it("decodes all-! to 0", () => {
      expect(base91ToNumber("!!!!")).toBe(0);
    });

    it("decodes single character correctly", () => {
      // 'A' === 65, digit = 65 - 33 = 32
      expect(base91ToNumber("A")).toBe(32);
    });

    it("should decode multiple Base91 characters", () => {
      // "!!" = 0 * 91 + 0 = 0
      expect(base91ToNumber("!!")).toBe(0);

      // "!#" = 0 * 91 + 2 = 2
      expect(base91ToNumber("!#")).toBe(2);

      // "#!" = 2 * 91 + 0 = 182
      expect(base91ToNumber("#!")).toBe(182);

      // "##" = 2 * 91 + 2 = 184
      expect(base91ToNumber("##")).toBe(184);
    });

    it("should decode 4-character Base91 strings (used in APRS)", () => {
      // Test with printable ASCII Base91 characters (33-123)
      const testValue = base91ToNumber("!#%'");
      expect(testValue).toBeGreaterThan(0);
      expect(testValue).toBeLessThan(91 * 91 * 91 * 91);
    });

    it("should decode maximum valid Base91 value", () => {
      // Maximum is '{' (ASCII 123, digit 90) repeated
      const maxValue = base91ToNumber("{{{{");
      const expected = 90 * 91 * 91 * 91 + 90 * 91 * 91 + 90 * 91 + 90;
      expect(maxValue).toBe(expected);
    });

    it("should handle APRS compressed position example", () => {
      // Using actual characters from APRS test vector
      const latStr = "/:*E";
      const lonStr = "qZ=O";

      const latValue = base91ToNumber(latStr);
      const lonValue = base91ToNumber(lonStr);

      // Just verify they decode without error and produce valid numbers
      expect(typeof latValue).toBe("number");
      expect(typeof lonValue).toBe("number");
      expect(latValue).toBeGreaterThanOrEqual(0);
      expect(lonValue).toBeGreaterThanOrEqual(0);
    });

    it("throws on invalid character", () => {
      expect(() => base91ToNumber(" ")).toThrow(); // space (code 32) is invalid
    });
  });

  describe("unit conversions", () => {
    it("converts knots <-> km/h", () => {
      expect(knotsToKmh(10)).toBeCloseTo(18.52, 5);
      expect(kmhToKnots(18.52)).toBeCloseTo(10, 3);
    });

    it("converts feet <-> meters", () => {
      expect(feetToMeters(10)).toBeCloseTo(3.048, 6);
      expect(metersToFeet(3.048)).toBeCloseTo(10, 6);
    });

    it("converts celsius <-> fahrenheit", () => {
      expect(celsiusToFahrenheit(0)).toBeCloseTo(32, 6);
      expect(fahrenheitToCelsius(32)).toBeCloseTo(0, 6);
      expect(celsiusToFahrenheit(100)).toBeCloseTo(212, 6);
      expect(fahrenheitToCelsius(212)).toBeCloseTo(100, 6);
    });
  });
});