# frozen_string_literal: true

=begin
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
/* Latitude/longitude spherical geodesy tools                         (c) Chris Veness 2002-2016  */
/*                                                                                   MIT Licence  */
/* www.movable-type.co.uk/scripts/latlong.html                                                    */
/* www.movable-type.co.uk/scripts/geodesy/docs/module-latlon-spherical.html                       */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  */
Código portado de biblioteca LatLon do JS
=end

class Map::LatLonService
  attr_reader :lat, :lon

  def initialize(lat_or_coordinate, lon = nil)
    if lon
      @lat = lat_or_coordinate.to_f
      @lon = lon.to_f
    elsif lat_or_coordinate.is_a?(Array)
      @lat = lat_or_coordinate.first.to_f
      @lon = lat_or_coordinate.second.to_f
    elsif lat_or_coordinate.is_a?(Hash)
      lat = HashWithIndifferentAccess.new(lat_or_coordinate)
      @lat = lat[:latitude].to_f
      @lon = lat[:longitude].to_f
    else
      raise 'Parâmetros inválidos'
    end

    Float.include Map::Float
  end

  def bearing_to(point)
    raise 'Point não é do tipo LatLon' unless point.is_a?(Map::LatLonService)

    _φ1 = self.lat.to_radians
    _φ2 = point.lat.to_radians
    _Δλ = (point.lon - self.lon).to_radians

    y = Math.sin(_Δλ) * Math.cos(_φ2)
    x = Math.cos(_φ1) * Math.sin(_φ2) - Math.sin(_φ1) * Math.cos(_φ2) * Math.cos(_Δλ)
    θ = Math.atan2(y, x)

    (θ.to_degrees + 360) % 360
  end

  def destination_point(distance, bearing)
    radius = 6371e3

    # _φ2 = asin( sin_φ1⋅cosδ + cos_φ1⋅sinδ⋅cosθ )
    # _λ2 = _λ1 + atan2( sinθ⋅sinδ⋅cos_φ1, cosδ − sin_φ1⋅sin_φ2 )
    # see http://williams.best.vwh.net/avform.htm#LL

    δ = distance / radius
    θ = bearing.to_f.to_radians

    _φ1 = self.lat.to_radians
    _λ1 = self.lon.to_radians

    _φ2 = Math.asin(Math.sin(_φ1)*Math.cos(δ) + Math.cos(_φ1)*Math.sin(δ)*Math.cos(θ))
    x = Math.cos(δ) - Math.sin(_φ1) * Math.sin(_φ2)
    y = Math.sin(θ) * Math.sin(δ) * Math.cos(_φ1)
    _λ2 = _λ1 + Math.atan2(y, x)

    self.class.new(_φ2.to_degrees, (_λ2.to_degrees + 540) % 360-180)
  end

  def distance_to(point)
    radius = 6371e3

    _φ1 = self.lat.to_radians
    _λ1 = self.lon.to_radians

    _φ2 = point.lat.to_radians
    _λ2 = point.lon.to_radians

    _Δφ = _φ2 - _φ1
    _Δλ = _λ2 - _λ1

    a = Math.sin(_Δφ/2) * Math.sin(_Δφ/2) + Math.cos(_φ1) * Math.cos(_φ2) * Math.sin(_Δλ/2) * Math.sin(_Δλ/2)
    c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a))

    radius * c
  end

  def to_hash
    {
      latitude: self.lat,
      longitude: self.lon
    }
  end
end