# <<*>> -^v- SNOWARE APPLICATION
# usage: MINESENTINEL mainloop.
# author: S.A.
# time: 2026-06-07
# Copyright (c) [2026] [S.A. SNOWARE-SCU]
# [MineSentinel] is licensed under Mulan PubL v2.
# You can use this software according to the terms and conditions of the Mulan PubL v2.
# You may obtain a copy of Mulan PubL v2 at:
#          http://license.coscl.org.cn/MulanPubL-2.0
# THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
# EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
# MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
# See the Mulan PubL v2 for more details.

# frozen_string_literal: true

# rubocop:disable Metrics/MethodLength, Metrics/AbcSize
def main
  puts '              ___  __   ___      ___         ___      '
  puts ' |\/| | |\ | |__  /__` |__  |\ |  |  | |\ | |__  |    '
  puts ' |  | | | \| |___ .__/ |___ | \|  |  | | \| |___ |___ '
  puts ' MineSentinel dev-rolling version by <*> S.A. [@SNOWARE] and owned by SCU team.'
  puts ' Copyleft (c) 2026 S.A. SNOWARE-SCU. This program is licensed under Mulan PubL v2.'
  puts ' E-mail: SALflake@qq.com | QQ: 758522192 | Website: https://swe-iss.rth1.xyz/softwares/minesentinel.'
  puts

  require_relative 'method_executor' # 日志系统在此时初始化
  MethodExecutor.record('debug', 'init',
                        'Initialized MethodExecutor, which implements logging system and intervening functions.')
  require_relative 'server_status_detector'
  require_relative 'systemd_notifier' # 心跳系统在此时初始化
  require_relative 'config'
  MethodExecutor.record('debug', 'init', 'Initialized SystemdNotifier, which implements systemd watchdog feeder.')

  # 确认是否具有展开干预操作的权限 如果因场景不同不需要请注释这部分内容
  unless Process.euid.zero?
    MethodExecutor.record('error', 'init', 'Permission denied: root required to intervene Systemd Services.')
    raise Errno::EPERM
  end

  MethodExecutor.record('info', 'mainloop', 'MineSentinel started, entering mainloop.')

  require_relative 'updates'

  begin
    upd_result = UpdateManager.check
    if upd_result[:status] == :NewerAvailable
      MethodExecutor.record('info', 'updates',
                            "Update #{upd_result[:version]} available, please check the git repo for details.")
    end
  rescue StandardError => e
    MethodExecutor.record('error', 'updates', e.to_s)
  end

  # 初次启动：MineSentinel 先于 minecraft 启动（systemd Before=），
  # 等待服务器端口就绪，避免误判为崩溃
  MethodExecutor.record('info', 'mainloop',
                        "Initial startup grace period #{INITIAL_GRACE}s — waiting for server to come up...")
  grace_deadline = Time.now + INITIAL_GRACE
  while Time.now < grace_deadline
    sleep 5
    next unless ServerStatusDetector::MinecraftServer.self_diag[:type]

    MethodExecutor.record('info', 'mainloop',
                          'Server port is open during grace period, resuming normal monitoring.')
    break
  end
  MethodExecutor.record('info', 'mainloop', 'Grace period ended.')
  main_loop
end

# rubocop:enable Metrics/MethodLength, Metrics/AbcSize
# Functional mainloop.
# rubocop:disable Metrics/MethodLength, Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def main_once
  chkrslts = []
  (0...TRY_TIMES).each do
    chkrslt = ServerStatusDetector::MinecraftServer.self_diag
    chkrslts.append(chkrslt)
  end
  if chkrslts.all? { |chkrslt_in| chkrslt_in[:type] }
    MethodExecutor.record('debug', 'mainloop', 'Server health check passed.')
  else
    chkrslts.each do |result|
      MethodExecutor.record('warn', 'mainloop', "Server health check FAILED: #{result[:message]}")
    end
    MethodExecutor.record('info', 'mainloop', "Checked #{TRY_TIMES} time.")
    if chkrslts.any? { |chkrslt_in| chkrslt_in[:operation].include?('Record') }
      MethodExecutor.record('warn', 'mainloop', 'Action: Record -> Server died!')
      if chkrslts.any? { |chkrslt_in| chkrslt_in[:message] == 'Server died for unknown reason, and will be restarted.' }
        MethodExecutor.record('info', 'mainloop', 'Action: ForceResetServerProcess triggered.')
        MethodExecutor.reset_minecraft_server
        # 重启后等待服务器启动（MC服务器启动通常需要30秒~2分钟）
        cooldown_beg = Time.now
        MethodExecutor.record('info', 'mainloop', "Cooling down #{RST_COOLDOWN_DURATION}s for server startup...")
        # rubocop:disable Metrics/BlockNesting
        while Time.now < cooldown_beg + RST_COOLDOWN_DURATION
          sleep 1
          SystemdNotifier.notify('WATCHDOG=1')
        end
        # rubocop:enable Metrics/BlockNesting
        MethodExecutor.record('info', 'mainloop', 'Cooldown finished, resuming monitoring.')
      end
    end
  end
end

# rubocop:enable Metrics/MethodLength, Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
def main_loop
  loop do
    sleep CHECK_INTERVAL
    SystemdNotifier.notify('WATCHDOG=1')
    main_once
  end
end

begin
  main
rescue StandardError => e
  # 强制输出到stderr
  warn "[CRITICAL] Unhandled exception: #{e.message}"
  warn e.backtrace&.join("\n")
  exit 1
end