require 'net/http'
require 'json'
require 'curb'

module Hue
  class Client
    attr_reader :username

    def initialize(username = nil)
      username = find_username unless @username

      @username = username

      if @username
        begin
          validate_user
        rescue Hue::UnauthorizedUser
          register_user
        end
      else
        register_user
      end
    end

    def bridge
      # Pick the first one for now. In theory, they should all do the same thing.
      bridge = bridges.first
      raise NoBridgeFound unless bridge
      bridge
    end

    def bridges
      @bridges ||= begin
        bs = []
        easy = Curl::Easy.new
        easy.follow_location = true
        easy.max_redirects = 10
        easy.url = 'https://www.meethue.com/api/nupnp'
        easy.perform
        JSON(easy.body).each do |hash|
          bs << Bridge.new(self, hash)
        end
        bs
      end
    end

    def lights
      bridge.lights
    end

    def add_lights
      bridge.add_lights
    end

    def light(id)
      id = id.to_s
      lights.select { |l| l.id == id }.first
    end

    def groups
      bridge.groups
    end

    def group(id = nil)
      return Group.new(self, bridge) if id.nil?

      id = id.to_s
      groups.select { |g| g.id == id }.first
    end

    def scenes
      bridge.scenes
    end

    def scene(id)
      id = id.to_s
      scenes.select { |s| s.id == id }.first
    end

    private

    def find_username
      return ENV['HUE_USERNAME'] if ENV['HUE_USERNAME']

      json = JSON(File.read(File.expand_path('~/.hue')))
      json['username']
    rescue
      return nil
    end

    def validate_user
      response = JSON(Net::HTTP.get(URI.parse("http://#{bridge.ip}/api/#{@username}")))

      if response.is_a? Array
        response = response.first
      end

      if error = response['error']
        raise get_error(error)
      end

      response['success']
    end

    def register_user
      body = JSON.dump({
        devicetype: 'Ruby'
      })

      uri = URI.parse("http://#{bridge.ip}/api")
      http = Net::HTTP.new(uri.host)
      response = JSON(http.request_post(uri.path, body).body).first

      if error = response['error']
        raise get_error(error)
      end

      if @username = response['success']['username']
        File.write(File.expand_path('~/.hue'), JSON.dump({username: @username}))
      end
    end

    def get_error(error)
      # Find error class and return instance
      klass = Hue::ERROR_MAP[error['type']] || UnknownError unless klass
      klass.new(error['description'])
    end
  end
end