module Miller

# File lib/miller.rb, line 82
def self.base(*args)
  Class.new do
    include Miller.with(*args)
    def self.inherited(subclass)
      unless config.empty?
        subclass._set_config_from_inheritance(config.dup)
      end
    end
  end
end

# File lib/miller.rb, line 14
def self.build(hash)
  hash.each_with_object(new) do |(k, v), o|
    o[k] = v
  end
end

# File lib/miller.rb, line 93
def self.extract_options!(ary)
  if ary.last.is_a?(Hash) && extractable_options?(ary.last)
    ary.pop
  else
    {}
  end
end

# File lib/miller.rb, line 101
def self.extractable_options?(elem)
  elem.instance_of?(Hash)
end

# File lib/miller.rb, line 85
def self.inherited(subclass)
  unless config.empty?
    subclass._set_config_from_inheritance(config.dup)
  end
end

# File lib/miller.rb, line 7
def self.with(*attrs)

  opts = extract_options!(attrs)

  config_class = Class.new(Hash) do
    alias_method :get, :[]
    alias_method :set, :[]=
    def self.build(hash)
      hash.each_with_object(new) do |(k, v), o|
        o[k] = v
      end
    end
    attrs.each do |attr|
      define_method attr do
        get(attr)
      end
    end

    def method_missing(name, *args, &block)
      raise ConfigNotSetError, { name: name }
    end
  end

  class_methods = Module.new do

    define_method :config do
      @config ||= config_class.build(opts[:default_config] || {})
    end

    def _set_config_from_inheritance(config)
      @config = config
    end

    attrs.each do |attr|
      define_method attr do |val = nil, &block|
        config.set(attr, (block || val))
      end
    end
  end

  instance_module = Module.new do
    def config
      self.class.config
    end
    attrs.each do |attr|
      define_method attr do
        result = instance_variable_get("@#{attr}")
        if result
          _extract_config(result)
        else
          _extract_config(self.class.config.get(attr))
        end
      end
    end
    attr_writer *attrs

    private

    def _extract_config(val)
      if val.respond_to?(:call)
        instance_exec(&val)
      else
        val
      end
    end
  end

  Module.new do
    singleton_class.send :define_method, :included do |host_class|
      host_class.extend class_methods
      host_class.include instance_module
    end
  end
end

# File lib/miller.rb, line 65
def _extract_config(val)
  if val.respond_to?(:call)
    instance_exec(&val)
  else
    val
  end
end

# File lib/miller.rb, line 36
def _set_config_from_inheritance(config)
  @config = config
end

# File lib/miller.rb, line 48
def config
  self.class.config
end

# File lib/miller.rb, line 25
def method_missing(name, *args, &block)
  raise ConfigNotSetError, { name: name }
end