require "xxhash"
require "sequel"
require "json"

ALPHANUM = [*"0".."9", *"A".."Z", *"a".."z", "-", "_"].freeze

# DataBase handler module
module Players
  db_file = File.expand_path("infinsweeper.db")
  DB = Sequel.connect("sqlite:///#{db_file}", single_threaded: false)

  def self.list
    DB["select * from Players"].all
  end

  def self.rm_player(email)
    DB["delete from Players where email = ?", email].delete
  end

  def self.mk_player(username, email, pass)
    raise ArgumentError, "Email format is wrong!" unless email.match?(/\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/)
    raise ArgumentError, "Username must be at least 4 characters long and of valid format." unless
      username.match?(/\A[a-zA-Z][a-zA-Z0-9_.-]+\z/) && username.length >= 4
    raise ArgumentError, "Password must be at least 8 characters and of valid format." unless
      pass.match?(/\A[a-zA-Z0-9_.!?@#$%^&*()+=-]+\z/) && pass.length >= 8

    digest = XXhash.xxh32(pass, 1234)

    path = File.expand_path("db.json")
    json = File.exist?(path) ? JSON.parse(File.read(path)) : {}
    json["account_num"] ||= 0
    account_num = json["account_num"]
    json["account_num"] += 1
    File.write(path, JSON.pretty_generate(json))
    account_num = XXhash.xxh64(account_num, 1234)
    code = ""
    while account_num.positive?
      code << ALPHANUM[account_num % 64]
      account_num /= 64
    end
    code = code.reverse.rjust(12, "0")

    DB[
      "insert into Players (email, digest, username, activation_code) values (?, ?, ?, ?)",
      email, digest, username, code
    ].insert

    send_email(:new, email, username, code)
    Thread.new do
      sleep 24 * 60 * 60
      rm_player(email) unless verified?(email)
    end

    "Successfully registered!"
  rescue ArgumentError => e
    e.message
  rescue Sequel::UniqueConstraintViolation
    "Account already exists with this email or username!"
  end

  def self.verify(code)
    DB["update Players set activation_code = ? where code = ?", "!", code].update != 0
  end

  def self.pass_req(email)
    path = File.expand_path("db.json")
    json = File.exist?(path) ? JSON.parse(File.read(path)) : {}
    json["pass_num"] ||= 0
    pass_num = json["pass_num"]
    json["pass_num"] += 1
    File.write(path, JSON.pretty_generate(json))
    pass_num = XXhash.xxh64(pass_num, 1234)
    code = ""
    while pass_num.positive?
      code << ALPHANUM[pass_num % 64]
      pass_num /= 64
    end
    code = code.reverse.rjust(12, "0")

    DB["update Players set new_pass_code = ? where email = ?", code, email].update

    send_email(:pass_req, email, code)
  end

  def self.pass_reset(new_pass, code)
    DB["update Players set pass = ? where new_pass_code = ?", new_pass, code].update != 0
  end

  def self.[](email)
    DB["select * from Players where email = ?", email].first
  end

  def self.[]=(email, data)
    DB["update Players set data = ? where email = ?", data, email].update
  end

  def self.authorized?(email, pass)
    digest = XXhash.xxh32(pass, 1234)
    player = self[email]
    player && player[:digest].to_i == digest.to_i ? player : false
  end

  def self.verified?(email)
    player = self[email]
    player && player[:code] == "!"
  end
end