import { describe, expect, it } from 'vitest'
import {
  hogTrimStartIndex,
  sampleTime,
  trimPathToStartAtHogLine,
  velocityToWeight,
  weightToVelocity,
} from './game-helpers'
import { SAMPLE_RATE_HZ } from './protocol'

describe('trimPathToStartAtHogLine', () => {
  it('trims path at the first hog-line crossing and preserves theta', () => {
    // (x, y, theta) — time is derived from index after trim
    const path: [number, number, number][] = [
      [0, 2, 0.1],
      [0, 20, 0.2],
      [0, 21.5, 0.3],
      [0, 30, 0.4],
    ]
    const trimmed = trimPathToStartAtHogLine(path)
    expect(trimmed[0][1]).toBe(20)
    expect(trimmed[0][2]).toBe(0.2)
    expect(trimmed[trimmed.length - 1][2]).toBe(0.4)
    expect(trimmed).toHaveLength(3)
  })

  it('returns full path when hog line is never reached', () => {
    const path: [number, number, number][] = [
      [0, 2, 0],
      [0, 10, 0.5],
    ]
    expect(trimPathToStartAtHogLine(path)).toEqual(path)
  })
})

describe('sampleTime', () => {
  it('is index / SAMPLE_RATE_HZ', () => {
    expect(sampleTime(0)).toBe(0)
    expect(sampleTime(SAMPLE_RATE_HZ)).toBe(1)
    expect(sampleTime(1)).toBeCloseTo(1 / SAMPLE_RATE_HZ)
  })
})

describe('hogTrimStartIndex', () => {
  it('returns index just before hog crossing', () => {
    const path: [number, number, number][] = [
      [0, 2, 0],
      [0, 20, 0],
      [0, 21.5, 0],
    ]
    expect(hogTrimStartIndex(path)).toBe(1)
  })
})

describe('velocity ↔ weight', () => {
  it('maps endpoints correctly', () => {
    expect(velocityToWeight(3.0)).toBe(1)
    expect(velocityToWeight(6.45)).toBe(10)
    expect(weightToVelocity(1)).toBe(3.0)
    expect(weightToVelocity(10)).toBe(6.45)
  })

  it('clamps out-of-range inputs', () => {
    expect(velocityToWeight(2.5)).toBe(1)
    expect(velocityToWeight(7.0)).toBe(10)
    expect(weightToVelocity(0)).toBe(3.0)
    expect(weightToVelocity(11)).toBe(6.45)
  })
})