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module FakeRedis
class GeoSet
class Point
BASE32 = "0123456789bcdefghjkmnpqrstuvwxyz" # (geohash-specific) Base32 map
EARTH_RADIUS_IN_M = 6_378_100.0
attr_reader :lon, :lat, :name
def initialize(lon, lat, name)
@lon = Float(lon)
@lat = Float(lat)
@name = name
end
def geohash(precision = 10)
latlon = [@lat, @lon]
ranges = [[-90.0, 90.0], [-180.0, 180.0]]
coordinate = 1
(0...precision).map do
index = 0 # index into base32 map
5.times do |bit|
mid = (ranges[coordinate][0] + ranges[coordinate][1]) / 2
if latlon[coordinate] >= mid
index = index * 2 + 1
ranges[coordinate][0] = mid
else
index *= 2
ranges[coordinate][1] = mid
end
coordinate ^= 1
end
BASE32[index]
end.join
end
def distance_to(other)
lat1 = deg_to_rad(@lat)
lon1 = deg_to_rad(@lon)
lat2 = deg_to_rad(other.lat)
lon2 = deg_to_rad(other.lon)
haversine_distance(lat1, lon1, lat2, lon2)
end
private
def deg_to_rad(deg)
deg * Math::PI / 180.0
end
def haversine_distance(lat1, lon1, lat2, lon2)
h = Math.sin((lat2 - lat1) / 2) ** 2 + Math.cos(lat1) * Math.cos(lat2) *
Math.sin((lon2 - lon1) / 2) ** 2
2 * EARTH_RADIUS_IN_M * Math.asin(Math.sqrt(h))
end
end
def initialize
@points = {}
end
def size
@points.size
end
def add(lon, lat, name)
@points[name] = Point.new(lon, lat, name)
end
def get(name)
@points[name]
end
def points_within_radius(center, radius)
@points.values.select do |point|
point.distance_to(center) <= radius
end
end
end
end
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