# Description:
#   Doge meme generator
#   Requires hubot-matrix adapter to access history
#
# Configuration:
#   Uses hubot-tg enviroment variables
#
# Commands
#   hubot doge [n] - crea un meme doge con messaggi recenti della chat
#
# Author:
#   Michele Guerini Rocco (rnhmjoj)
#


module.exports = (robot) ->
  matrix = robot.adapter.client
  return unless robot.adapterName is 'matrix' and matrix?

  # get the messages history for a chat room
  get_history = (room, size, callback) ->
    room = matrix.getRoom room.id
    matrix.scrollback room, size, (err, res) ->
      return callback err, null if err?
      return unless res.chunk?

      callback null, res.chunk.map (event) ->
        type: event.content.msgtype
        sender: robot.brain.userForId event.sender
        content: event.content.body

  # concat list of lists
  concat = (list) -> list.reduce (x, y) -> x.concat y

  # remove duplicates in a list
  nub = (list) -> Array.from new Set list

  # URL escape strings
  escape = (str) ->
    str.replace(/\d|\?|#/g,    '') # not supported
       .replace(     /\ /g, '%20') # spaces

  # format doge API URL
  doge_url = (text) ->
    "http://dogr.io/#{escape text}.png?split=false"

  # dogeify text
  doge = (res, words) ->
    prefix = [ 'much', 'such', 'many', 'very']
    word   = words.filter (x) ->
      /^[a-zA-ZàèéìòùÀÈÉÌÒÙ\-_!&@#?]{4,}$/.test x
    (res.random prefix) + ' ' + (res.random words)

  robot.respond /doge(?: (\d+))?/, (res) ->
    n = res.match[1] || 10
    get_history res.message.room, n, (err, history) ->
      return res.send "c'è stato un errore: #{err}" if err?

      words = ((nub concat (history.filter (msg) ->
        msg.type is 'm.text').map (msg) ->
          msg.content.split /\W/).sort (a, b) ->
            b.length - a.length).slice 0, 50

      sample = [0..15].map ->
        if Math.random() <= 0.2 then 'wow'
        else doge res, words
      res.send doge_url sample.join '/'