require "logger"
require "telepathy"
require "time"
require "sqlite3"
require "cron_scheduler"

EXTENSIONS = ["png", "jpeg", "jpg"]
LOGGER = Logger.new(STDOUT)

class PupperBot
   @db : DB::Database

  def initialize(@configuration : BotConfiguration)
    @telegram_bot = Telepathy::Bot.new configuration.token
    @db = DB.open "sqlite3://#{configuration.database}"
    initialize_db
    update_database
    initialize_timers
    initialize_telegram
    send_broadcast
  end

  private def initialize_db
    @db.exec "create table if not exists posts(id integer primary key, title text, url text unique)"
    @db.exec "create table if not exists recepient_posts(recepient integer, post integer, foreign key(post) references posts(id))"
  end

  private def initialize_timers
    CronScheduler.define do
      at(@configuration.send_cron) { send_broadcast }
      at(@configuration.refresh_cron) { update_database }
    end
  end

  private def initialize_telegram
    @telegram_bot.command "ping" do |update, args|
      @telegram_bot.send_message(update.message.as(Telepathy::Message).chat.id, "pong")
    end

    @telegram_bot.command "pupper" do |update, args|
      command_chatid = update.message.as(Telepathy::Message).chat.id
      send_single command_chatid
    end

    @telegram_bot.poll
  end

  def send_single(chatid)
    unsent_query = "select id, title, url from posts where not exists (select * from recepient_posts where recepient=? and post=id) limit 1"

    unless to_send = @db.query_one? unsent_query, chatid, as: { Int64, String, String }
      LOGGER.info "Unable to find a post to send to #{chatid}."
      return
    end

    id, title, url = to_send
    LOGGER.info "Using URL #{url} for request from #{chatid}"
    @db.exec "insert into recepient_posts(recepient, post) values(?, ?)", chatid, id
    @telegram_bot.send_photo(chatid, url, title)
  end

  def send_broadcast
    @configuration.recipients.each do |recepient|
      send_single recepient
    end
  end

  def update_database
    unless response = RedditResponse.from_subreddits(@configuration.subreddits)
      LOGGER.info "Unable to find more posts for the database"
      return
    end

    posts = response.data.posts_matching { |post| EXTENSIONS.any? { |it| post.url.ends_with? it } }
    posts.each do |post|
      LOGGER.info "Trying to save post #{post.title} #{post.url}"
      begin
        @db.exec "insert into posts(title, url) values(?, ?)", post.title, post.url
      rescue
      end
    end
  end
end