module Envvar

# File lib/envvar.rb, line 11
def self.load(file_path, env = (ENV['RACK_ENV'] || :development))
  config = YAML.load(ERB.new(open(file_path).read).result)

  set_environment(config, env.to_s)
  set_defaults(config)

  check_required(config)
end

# File lib/envvar.rb, line 48
def self.check_from_hash(config)
  config.each do |var|
    if ENV[var].nil?
      raise EnvironmentError.new("Required var #{var} not found in ENV hash")
    end
  end
end

# File lib/envvar.rb, line 34
def self.check_required(config)
  return if config[REQUIRED_KEY].nil?

  check_from_hash(config[REQUIRED_KEY])
end

# File lib/envvar.rb, line 22
def self.set_defaults(config)
  return if config[DEFAULTS_KEY].nil?

  set_from_hash(config[DEFAULTS_KEY])
end

# File lib/envvar.rb, line 28
def self.set_environment(config, env)
  return if config[env].nil?

  set_from_hash(config[env])
end

# File lib/envvar.rb, line 40
def self.set_from_hash(config)
  config.each do |var, default|
    if ENV[var].nil?
      ENV[var] = default.to_s
    end
  end
end