require "set"

module Honeybadger
  class Config
    module Env
      CONFIG_KEY = /\AHONEYBADGER_(.+)\Z/
      CONFIG_MAPPING = DEFAULTS.keys.map { |k| [k.to_s.upcase.gsub(KEY_REPLACEMENT, "_"), k] }.to_h.freeze
      ARRAY_VALUES = Regexp.new('\s*,\s*').freeze
      IGNORED_TYPES = Set[Hash]

      def self.new(env = ENV)
        hash = {}

        env.each_pair do |k, v|
          next unless k.match(CONFIG_KEY)
          next unless (config_key = CONFIG_MAPPING[$1])
          type = OPTIONS[config_key][:type]
          next if IGNORED_TYPES.include?(type)
          hash[config_key] = cast_value(v, type)
        end

        hash
      end

      def self.cast_value(value, type = String)
        v = value.to_s

        if type == Boolean
          !!(v =~ /\A(true|t|1)\z/i)
        elsif type == Array
          v.split(ARRAY_VALUES).map(&method(:cast_value))
        elsif type == Integer
          v.to_i
        elsif type == Float
          v.to_f
        else
          v
        end
      end
    end
  end
end
