class Middleman::Configuration::ConfigurationManager

def [](key)
  setting = @settings[key]
  setting ? setting.value : nil
end

def []=(key, val)
  setting = @settings[key] || define_setting(key)
  setting.value = val
end

def all_settings
  @settings.values.sort_by(&:key)
end

def define_setting(key, default=nil, description=nil)
  raise "Setting #{key} doesn't exist" if @finalized
  raise "Setting #{key} already defined" if @settings.has_key?(key)
  raise "Setting key must be a Symbol" unless key.is_a? Symbol
  @settings[key] = ConfigSetting.new(key, default, description)
end

def defines_setting?(key)
  @settings.has_key?(key)
end

def dup
  ConfigurationManager.new.tap {|c| c.load_settings(self.all_settings) }
end

def finalize!
  @finalized = true
  self
end

def initialize
  # A hash from setting key to ConfigSetting instance.
  @settings = {}
  @finalized = false
end

def load_settings(other_settings)
  other_settings.each do |setting|
    new_setting = define_setting(setting.key, setting.default, setting.description)
    new_setting.value = setting.value if setting.value_set?
  end
end

def method_missing(method, *args)
  if defines_setting?(method) && args.size == 0
    self[method]
  elsif method.to_s =~ /^(\w+)=$/ && args.size == 1
    self[$1.to_sym] = args[0]
  else
    super
  end
end

def respond_to?(method, include_private = false)
  super || defines_setting?(method) || (method =~ /^(\w+)=$/ && defines_setting?($1))
end

def setting(key)
  @settings[key]
end

def to_h
  hash = {}
  @settings.each do |key, setting|
    hash[key] = setting.value
  end
  hash
end

def to_s
  to_h.inspect
end