import { describe, it, expect } from 'vitest';
import { applyTransform } from '../src/modules/datapoints/transforms';

describe('applyTransform', () => {
  describe('no transform', () => {
    it('should return value unchanged when config is null', () => {
      expect(applyTransform('42', null)).toBe('42');
    });

    it('should return value unchanged when config is empty object', () => {
      expect(applyTransform('hello', {})).toBe('hello');
    });

    it('should return non-numeric string unchanged with no transform', () => {
      expect(applyTransform('running', null)).toBe('running');
    });
  });

  describe('round', () => {
    it('should round to specified decimal places', () => {
      expect(applyTransform('3.14159', { round: 2 })).toBe('3.14');
    });

    it('should round to 0 decimal places', () => {
      expect(applyTransform('3.7', { round: 0 })).toBe('4');
    });

    it('should round to integer by default when round is 0', () => {
      expect(applyTransform('2.5', { round: 0 })).toBe('3');
    });

    it('should return non-numeric string unchanged when rounding', () => {
      expect(applyTransform('N/A', { round: 2 })).toBe('N/A');
    });
  });

  describe('scale', () => {
    it('should multiply value by scale factor', () => {
      expect(applyTransform('100', { scale: 0.1 })).toBe('10');
    });

    it('should apply scale and round together', () => {
      expect(applyTransform('100', { scale: 0.333, round: 1 })).toBe('33.3');
    });

    it('should return non-numeric string unchanged when scaling', () => {
      expect(applyTransform('unknown', { scale: 2 })).toBe('unknown');
    });
  });

  describe('map', () => {
    it('should map matching value to its mapped result', () => {
      expect(applyTransform('1', { map: { '1': 'Online', '0': 'Offline' } })).toBe('Online');
    });

    it('should map another matching value', () => {
      expect(applyTransform('0', { map: { '1': 'Online', '0': 'Offline' } })).toBe('Offline');
    });

    it('should return original value when no map key matches', () => {
      expect(applyTransform('2', { map: { '1': 'Online', '0': 'Offline' } })).toBe('2');
    });

    it('map should take priority over scale and round', () => {
      expect(
        applyTransform('1', { map: { '1': 'yes' }, scale: 10, round: 2 })
      ).toBe('yes');
    });
  });

  describe('combined transforms', () => {
    it('should apply scale then round', () => {
      expect(applyTransform('1000', { scale: 0.001, round: 2 })).toBe('1');
    });

    it('should handle negative scale', () => {
      expect(applyTransform('10', { scale: -1 })).toBe('-10');
    });

    it('should handle large round precision', () => {
      expect(applyTransform('1.23456789', { round: 5 })).toBe('1.23457');
    });
  });
});