class 'Rub' {
  url = 'https://api.factmaven.com/xml-to-json/?xml=https://www.cbr.ru/scripts/XML_daily.asp',
  pat = '%d %s (%s) - %f ₽',

  function(this)
    this.tools = require 'api.tools'
  end,

  getPat = function(this, val)
    return this.pat:format(val.Nominal, val.Name, val.CharCode, val.Value:gsub(',', '.'))
  end,

  course = function(this, wants)
    local res, ok = this.tools._req(this.url, 'GET')
    if not ok
    then return 'err'
    end
    res = this.tools.json.decode(res or '{}')
    res = res.ValCurs
    if not res
    then return 'err'
    end

    -- Pseudo-valutes
    table.insert(res.Valute, {
      ID = 'R01000',
      NumCode = '001',
      CharCode = 'RUB',
      Nominal = 1,
      Name = 'Российский рубль',
      Value = '1',
    })
    local uah = table.findV(res.Valute, {CharCode = 'UAH'})
    assert(uah, 'No UAH found')
    table.insert(res.Valute, {
      ID = 'R02000',
      NumCode = '200',
      CharCode = 'SHT',
      Nominal = 1,
      Name = 'Штаны',
      Value = ('%f'):format(tonumber(uah.Value:gsub(',', '.'), nil) / uah.Nominal * 40), -- 40 UAH
    })

    local r, founds = {}, {}
    if table.find(wants, 'ALL') then
      for _, v in pairs(res.Valute)
      do table.insert(r, this:getPat(v))
      end
      return r, res.Date, wants -- string, date, found
    end

    for _, v in pairs(res.Valute) do
      if table.find(wants, v.CharCode) then
        table.insert(founds, v.CharCode)
	table.insert(r, this:getPat(v))
      end
    end
    return r, res.Date, founds --
  end,
}

local rub = new 'Rub' ()

return {
  run = function(self, msg)
    local wants = {
      'USD',
      'EUR',
      table.unpack(msg.args)
    }
    for i = 1, #wants do
      wants[i] = wants[i]:upper()
    end
    local v, d, f = rub:course(wants)
    if v == 'err' then
      return self.api:reply(msg, self.locale:get('error', 'req_err', msg.l))
    end
    local nf = { }
    for _, i in pairs(wants) do
      if not table.find(f, i) then
        table.insert(nf, i)
      end
    end
    local s = msg.loc.cur:format(d, table.concat(v, '\n'))
    if #nf > 0 then
      s = s .. msg.loc.notf .. table.concat(nf, ',')
    end
    self.api:reply(msg, s .. msg.loc.prov)
  end
}