import 'package:hgdj/hj_utils/text_util.dart';
import 'package:hgdj/tools_base/net/net_manager.dart';

class DateTimeUtil {
  /// 计算当前时间差值
  static int calTime3(String? date) {
    if (TextUtil.isEmpty(date) || date?.contains("0001-01-01") == true)
      return -1;
    final time = DateTime.parse(utc2iso(date)).toLocal();
    return time.difference(DateTime.now()).inSeconds;
  }

  /// 日期时间本地格式化 yyyy-MM-dd HH:mm:ss
  static String utc2iso(String? formattedString) {
    if (formattedString == null || formattedString.isEmpty) return '';
    try {
      final dt = DateTime.parse(formattedString).toLocal();
      return '${_fourDigits(dt.year)}-${_twoDigits(dt.month)}-${_twoDigits(dt.day)} '
          '${_twoDigits(dt.hour)}:${_twoDigits(dt.minute)}:${_twoDigits(dt.second)}';
    } catch (e) {
      return '';
    }
  }

  /// utc 转 MM月dd日
  static String utc2isoMD(String? formattedString) {
    if (formattedString == null || formattedString.isEmpty) return '';
    try {
      final dt = DateTime.parse(formattedString).toLocal();
      return '${_twoDigits(dt.month)}月${_twoDigits(dt.day)}日';
    } catch (e) {
      return '';
    }
  }

  /// 2020-11-26T17:44:45.000Z
  static String? format2utc(DateTime dateTime) {
    return '${_fourDigits(dateTime.year)}-${_twoDigits(dateTime.month)}-${_twoDigits(dateTime.day)}'
        'T${_twoDigits(dateTime.hour)}:${_twoDigits(dateTime.minute)}:${_twoDigits(dateTime.second)}'
        '.${_threeDigits(dateTime.millisecond)}Z';
  }

  /// 4 位补零（年份），负数前置符号，例：5 → "0005"，-5 → "-0005"
  static String _fourDigits(int n) {
    final absN = n.abs();
    final sign = n < 0 ? '-' : '';
    if (absN >= 1000) return '$n';
    if (absN >= 100) return '${sign}0$absN';
    if (absN >= 10) return '${sign}00$absN';
    return '${sign}000$absN';
  }

  /// 3 位补零（毫秒），例：5 → "005"
  static String _threeDigits(int n) {
    if (n >= 100) return '$n';
    if (n >= 10) return '0$n';
    return '00$n';
  }

  /// 2 位补零（月/日/时/分/秒），例：5 → "05"
  static String _twoDigits(int n) {
    if (n >= 10) return '$n';
    return '0$n';
  }

  /// utc 转 年月日
  static String utcTurnYear(String? date,
      {String? char, bool? isChina, bool showHM = false}) {
    if (date == null || date.isEmpty) return '';
    final gap = char ?? '-';
    final dt = DateTime.parse(date).toLocal();
    final y = _fourDigits(dt.year);
    final m = _twoDigits(dt.month);
    final d = _twoDigits(dt.day);
    if (isChina == true) return '$y年$m月$d日';
    if (showHM == true) {
      return '$y$gap$m$gap$d ${_twoDigits(dt.hour)}:${_twoDigits(dt.minute)}';
    }
    return '$y$gap$m$gap$d ';
  }

  static String utc3YearMonthDay(DateTime dateTime) {
    try {
      return '${_twoDigits(dateTime.year)}-${_twoDigits(dateTime.month)}-${_twoDigits(dateTime.day)} ';
    } catch (e) {
      return '';
    }
  }

  /// 计算字符串时间差值
  static String? calTimediffFromNow(String? date) {
    final time = DateTime.parse(date ?? '').toLocal();
    final difference = time.difference(DateTime.now());
    final day = difference.inDays;
    final hours = difference.inHours % 24;
    return '$day天$hours小时';
  }

  /// 秒 → MM:SS / HH:MM:SS（小时补零）。[alwaysHour] 为 true 时不足 1 小时也带小时位（00:MM:SS）
  /// 时长格式化的唯一入口，外部各处统一走这里
  static String formatHMS(int seconds, {bool alwaysHour = false}) {
    if (seconds < 0) seconds = 0;
    final h = seconds ~/ 3600;
    final m = (seconds % 3600) ~/ 60;
    final s = seconds % 60;
    final ms = '${_twoDigits(m)}:${_twoDigits(s)}';
    return (h == 0 && !alwaysHour) ? ms : '${_twoDigits(h)}:$ms';
  }

  /// 时长 → MM:SS / HH:MM:SS（统一走 [formatHMS]）
  static String? formatDuration(Duration position) =>
      formatHMS(position.inSeconds);

  /// 秒 → (时, 分, 秒) 各两位补零字符串；时为总小时数（不取模 24），供分段倒计时 UI 用
  static (String, String, String) hms(int seconds) => (
        _twoDigits(seconds ~/ 3600),
        _twoDigits((seconds ~/ 60) % 60),
        _twoDigits(seconds % 60),
      );

  /// 这个时间是否**还没到期**(晚于服务器当前时间)。名字有歧义，别按字面理解成「已过期」。
  /// 解析不了一律当没权益：这里被登录/刷新用户信息那条主路调用(见 GlobalStore._setMe)，
  /// 裸 DateTime.parse 遇到后端换格式会把整条链抛断，登录都进不去
  static bool isExpireDate(String? time) {
    if (time == null || time.isEmpty) return false;
    final dt = DateTime.tryParse(time);
    return dt != null && dt.isAfter(netManager.getFixedCurTime());
  }
}

/// 构建分秒 MM:SS
String buildMMSS(int seconds) {
  final minute = seconds ~/ 60;
  final second = seconds % 60;
  return '${_formatTime(minute)}:${_formatTime(second)}';
}

/// 数字格式化，将 0~9 的时间转换为 00~09
String _formatTime(int timeNum) => timeNum.toString().padLeft(2, '0');

const String kFormatTimeFallback = '—';

/// 最早可展示时间（早于该时间视为非正常）
final DateTime _kMinValidDateTime = DateTime(1970, 1, 1);

/// 非正常时间兜底：占位默认时间、过早/未来时间等不可用于展示
bool _isAbnormalDateTime(DateTime date, {DateTime? now}) {
  if (date.year <= 1) return true;
  if (date.isBefore(_kMinValidDateTime)) return true;
  final reference = now ?? DateTime.now();
  if (date.isAfter(reference)) return true;
  return false;
}

/// 解析时间；空值、解析失败、非正常时间返回 null
DateTime? _parseFormatTimeDate(String? utcTime) {
  if (utcTime == null || utcTime.trim().isEmpty) return null;
  try {
    final date = DateTime.parse(utcTime.trim()).toLocal();
    if (_isAbnormalDateTime(date)) return null;
    return date;
  } catch (_) {
    return null;
  }
}

bool _isSameDay(DateTime a, DateTime b) =>
    a.year == b.year && a.month == b.month && a.day == b.day;

/// 1 小时内 →「X分钟前」；当天 →「HH:mm」；其余 →「MM-DD HH:mm」；非正常时间 →「—」
String formatTime(String? utcTime,
    {String gap = '-', bool hasTimeGap = false}) {
  final date = _parseFormatTimeDate(utcTime);
  if (date == null) return kFormatTimeFallback;

  final now = DateTime.now();
  final diff = now.difference(date);

  if (diff.inHours < 1) {
    final minutes = diff.inMinutes;
    return minutes < 1 ? '1分钟前' : '$minutes分钟前';
  }

  if (_isSameDay(date, now)) {
    return '${DateTimeUtil._twoDigits(date.hour)}:${DateTimeUtil._twoDigits(date.minute)}';
  }

  return '${DateTimeUtil._twoDigits(date.month)}$gap${DateTimeUtil._twoDigits(date.day)} '
      '${DateTimeUtil._twoDigits(date.hour)}:${DateTimeUtil._twoDigits(date.minute)}';
}

String formatTimeTwo(String? utcTime) {
  if (utcTime?.isNotEmpty != true) return '近期';
  final now = DateTime.now();
  final date = DateTime.parse(utcTime!).toLocal();
  final changeTime =
      (now.millisecondsSinceEpoch - date.millisecondsSinceEpoch) ~/ 1000;

  final s = changeTime;
  if (s >= 0 && s < 60) return '刚刚';
  final m = s ~/ 60;
  if (m > 0 && m < 60) return '$m分钟前';
  final h = m ~/ 60;
  if (h > 0 && h < 24) return '$h小时前';
  final d = h ~/ 24;
  if (d > 0 && d < 7) return '$d天前';

  final w = d ~/ 7;
  if (w > 0 && w < 4) return '$w周前';

  final month = d ~/ 30;
  if (month > 0 && month < 12) return DateTimeUtil.utc2isoMD(utcTime);

  final year = month ~/ 12;
  if (year > 0 && year < 12)
    return DateTimeUtil.utcTurnYear(utcTime, isChina: true);
  return '';
}