require 'ostruct'
require 'redis'
require 'securerandom'
require 'yaml'

class CommentsRepository
  def initialize
    @redis = Redis.new
  end
  
  def save itemId, comment, parentId = nil
    @redis.del "item:#{itemId}:parsedComments"
    data = hashComment itemId, comment, parentId
    id = data[:id]
    if parentId == nil
      @redis.rpush "item:#{itemId}:comments", id
    else
      @redis.hset "comment:#{parentId}", 'hasChildrens', 1
      @redis.rpush "thread:#{data[:parentId]}", id
    end
    
    @redis.hmset "comment:#{id}", data.map{|k,v| [k,v]}.flatten(1)
    id
  end
  
  def get itemId
    parsedComments = @redis.get "item:#{itemId}:parsedComments"
    if true#!parsedComments
      data = multiFetch "item:#{itemId}:comments"
      parsedComments = processComments data
      @redis.set "item:#{itemId}:parsedComments", parsedComments.to_yaml
    else
      parsedComments = YAML.load parsedComments
    end
    parsedComments
  end
  
  private
  
  def hashComment itemId, comment, parentId
    {
      id: SecureRandom.uuid, 
      itemId: itemId,
      comment: comment, 
      parentId: parentId == nil ? itemId : parentId, 
      time: Time.now, 
      hasChildrens: 0
    }
  end
  
  def multiFetch keyName
    commentList = @redis.lrange keyName, 0, -1
    @redis.multi do |multi|
      commentList.map { |commentId| multi.hgetall "comment:#{commentId}" }
    end
  end
  
  def processComments comments
    result = Hash.new
    comments.each do |data|
      data = OpenStruct.new data
      result[data.id] = data
      if data.hasChildrens == '1'
        childData = multiFetch "thread:#{data.id}"
        data.comments = processComments childData
      end
    end
    result
  end
end