require 'redis'
class Redmiso
end

require 'redmiso/type'

class Redmiso
  class << self
    attr_accessor :default

    def redis
      # use Redis default by default
      @redis ||= Redis.new(default || {})
      @redis
    end

    def string(name)
      t = type(Type::String,name)
      define_method("#{name}=") do |value|
        t.set(value)
      end
    end

    def instance_field
    end

    def class_field
    end

    def type(type,name)
      t = type.new(redis,"#{self}.#{name}")
      self.class_eval do
        define_method(name) do |&block|
          if block
            t.instance_eval(block)
          else
            t.value
          end
        end
      end
      t
    end

    def exist?(id)
      r = redis.sismember(id_set,id)
      r
    end

    def create(id=nil)
      id ||= redis.incr(auto_increment)
      unless redis.sadd(id_set,id)
        raise "can't create with existing id: #{id}"
      end
      self.new(id)
    end

    def delete(id)
      if redis.srem(id_set,id) == 0
        raise "can't delete id: #{id}"
      end
    end

    def ids
      redis.smembers(id_set).map(&:to_i)
    end

    def all
      ids.map { |id| self.new(id) }
    end

    def count
      redis.scard(id_set)
    end

    def [](id)
      self.new(id) if exist?(id)
    end

    def vacuum
      # clean up everything not in root set
      raise "abstract"
      redis.keys("#{self}.*")
      # then extrat ids of fields, and check existence in rootset
    end

    def garbage
      # return attributes of objects not in rootset
    end

    private
    # this is the ROOT for this class
    def id_set
      @id_set ||= "#{self}#ids"
      @id_set
    end

    def auto_increment
      @auto_increment ||= "#{self}#auto_increment"
      @auto_increment
    end
  end

  def redis
    self.class.redis
  end

  attr_reader :id
  def initialize(id)
    @id = id
  end

  def delete
    self.class.delete(id)
  end

  def exist?
    self.class.exist?(id)
  end

  def ==(obj)
    obj.class == self.class && obj.id == self.id
  end
end