describe 'LineSegment', ->
  LineSegment = require 'lib/world/line_segment'
  Vector = require 'lib/world/vector'

  v00 = new Vector(0, 0)
  v11 = new Vector(1, 1)
  v22 = new Vector(2, 2)
  v34 = new Vector(3, 4)
  v04 = new Vector(0, 4)
  v30 = new Vector(3, 0)
  vneg = new Vector(-1, -1)

  it 'intersects itself', ->
    lineSegment = new LineSegment v00, v34
    expect(lineSegment.intersectsLineSegment lineSegment).toBe true

  it 'intersects other segments properly', ->
    l1 = new LineSegment v00, v34
    l2 = new LineSegment v04, v30
    l3 = new LineSegment v00, v11
    expect(l1.intersectsLineSegment l2).toBe true
    expect(l2.intersectsLineSegment l1).toBe true
    expect(l1.intersectsLineSegment l3).toBe true
    expect(l3.intersectsLineSegment l1).toBe true
    expect(l2.intersectsLineSegment l3).toBe false
    expect(l3.intersectsLineSegment l2).toBe false

  it 'can tell when a point is on a line or segment', ->
    lineSegment = new LineSegment v00, v11
    expect(lineSegment.pointOnLine v22, false).toBe true
    #expect(lineSegment.pointOnLine v22, true).toBe false
    #expect(lineSegment.pointOnLine v00, false).toBe true
    #expect(lineSegment.pointOnLine v00, true).toBe true
    #expect(lineSegment.pointOnLine v11, true).toBe true
    #expect(lineSegment.pointOnLine v11, false).toBe true
    #expect(lineSegment.pointOnLine v34, false).toBe false
    #expect(lineSegment.pointOnLine v34, true).toBe false

  it 'correctly calculates distance to points', ->
    lineSegment = new LineSegment v00, v11
    expect(lineSegment.distanceToPoint v00).toBe 0
    expect(lineSegment.distanceToPoint v11).toBe 0
    expect(lineSegment.distanceToPoint v22).toBeCloseTo Math.SQRT2
    expect(lineSegment.distanceToPoint v34).toBeCloseTo Math.sqrt(2 * 2 + 3 * 3)
    expect(lineSegment.distanceToPoint v04).toBeCloseTo Math.sqrt(1 * 1 + 3 * 3)
    expect(lineSegment.distanceToPoint v30).toBeCloseTo Math.sqrt(2 * 2 + 1 * 1)
    expect(lineSegment.distanceToPoint vneg).toBeCloseTo Math.SQRT2

    nullSegment = new LineSegment v11, v11
    expect(lineSegment.distanceToPoint v11).toBe 0
    expect(lineSegment.distanceToPoint v22).toBeCloseTo Math.SQRT2