# frozen_string_literal: true

# (The MIT License)
#
# Copyright (c) 2018-2019 Yegor Bugayenko
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the 'Software'), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

require 'telebot'

# Telepost is a simple gateway to Telegram, which can post messages and
# respond to primitive requests:
#
#  require 'telepost'
#  tp = Telepost.new('... secret token ...')
#  tp.run do |chat, msg|
#    # Reply to the message via tp.post(msg, chat)
#  end
#
# For more information read
# {README}[https://github.com/yegor256/telepost/blob/master/README.md] file.
#
# Author:: Yegor Bugayenko (yegor256@gmail.com)
# Copyright:: Copyright (c) 2018-2019 Yegor Bugayenko
# License:: MIT
class Telepost
  # Fake one
  class Fake
    attr_reader :sent
    def initialize
      @sent = []
    end

    def run
      # Nothing to do here
    end

    def spam(*lines)
      post(0, lines)
    end

    def post(chat, *lines)
      @sent << "#{chat}: #{lines.join(' ')}"
    end
  end

  # When can't post a message
  class CantPost < StandardError; end

  # To make it possible to get the client.
  attr_reader :client

  # Makes a new object. To obtain a token you should talk
  # to the @BotFather in Telegram.
  def initialize(token, chats: [])
    @token = token
    @client = Telebot::Client.new(token)
    @chats = chats
  end

  # You can run a chat bot to listen to the messages coming to it, in
  # a separate thread.
  def run
    Telebot::Bot.new(@token).run do |chat, message|
      if block_given?
        yield(chat, message)
      elsif !chat.nil?
        id = message.chat.id
        if id.positive?
          post(
            "This is your chat ID: `#{message.chat.id}`.",
            chat: message.chat.id
          )
        end
      end
    end
  rescue Net::OpenTimeout
    retry
  end

  # Send the message (lines will be concatenated with a space
  # between them) to the chats provided in the constructor
  # and encapsulated.
  def spam(*lines)
    @chats.each do |chat|
      post(chat, lines)
    end
  end

  # Post a single message to the designated chat room. The
  # chat argument can either me an integer, if you know the
  # chat ID, or the name of the channel (your bot has to
  # be the admin there). The lines provided will be
  # concatenated with a space between them.
  def post(chat, *lines)
    msg = lines.join(' ')
    @client.send_message(
      chat_id: chat,
      parse_mode: 'Markdown',
      disable_web_page_preview: true,
      text: msg
    )
  rescue Telebot::Error => e
    raise CantPost, "#{e.message}: \"#{msg}\""
  end
end