import 'dart:math' as math;

import 'package:intl/intl.dart';

import '../../shared/l10n/l10n.dart';
import 'channel.dart';

class EphemeralChannelDisplay {
  final String? detailLabel;
  final String tooltipLabel;

  const EphemeralChannelDisplay({
    required this.detailLabel,
    required this.tooltipLabel,
  });
}

bool isEphemeralChannel(Channel channel) =>
    channel.ttlSeconds != null || channel.ttlDeadline != null;

EphemeralChannelDisplay? ephemeralChannelDisplay(
  Channel channel, {
  DateTime? now,
  AppLocalizations? l10n,
}) {
  if (!isEphemeralChannel(channel)) return null;

  final deadline = channel.ttlDeadline;
  final remainingSeconds = deadline == null
      ? null
      : ((deadline.millisecondsSinceEpoch -
                    (now ?? DateTime.now()).millisecondsSinceEpoch) /
                1000)
            .ceil();

  if (remainingSeconds == null) {
    final ttlSeconds = channel.ttlSeconds;
    return EphemeralChannelDisplay(
      detailLabel: ttlSeconds == null
          ? null
          : formatCompactTtl(ttlSeconds, l10n: l10n),
      tooltipLabel: ttlSeconds == null
          ? l10n?.ephemeralAutoCleanup ??
                'Ephemeral channel. Cleans up automatically after inactivity.'
          : l10n?.ephemeralCleanupAfter(
                formatVerboseTtl(ttlSeconds, l10n: l10n),
              ) ??
              'Ephemeral channel. Cleans up after ${formatVerboseTtl(ttlSeconds)} of inactivity.',
    );
  }

  final compactRemaining = formatCompactRemaining(
    remainingSeconds,
    l10n: l10n,
  );
  final verboseRemaining = formatVerboseRemaining(
    remainingSeconds,
    l10n: l10n,
  );
  final absoluteDeadlineLabel = formatAbsoluteDeadline(deadline!, l10n: l10n);

  return EphemeralChannelDisplay(
    detailLabel: compactRemaining,
    tooltipLabel: remainingSeconds <= 0
        ? l10n?.ephemeralCleanupDueTooltip ??
              'Ephemeral channel. Cleanup is due now.'
        : l10n?.ephemeralScheduled(verboseRemaining, absoluteDeadlineLabel) ??
              'Ephemeral channel. Cleans up $verboseRemaining. Scheduled for $absoluteDeadlineLabel.',
  );
}

String formatCompactRemaining(
  int remainingSeconds, {
  AppLocalizations? l10n,
}) {
  if (remainingSeconds <= 0) return l10n?.ephemeralCleanupDue ?? 'Cleanup due';
  if (remainingSeconds <= 60) return l10n?.ephemeralOneMinuteLeft ?? '1m left';
  if (remainingSeconds < 60 * 60) {
    final minutes = math.max(1, (remainingSeconds / 60).ceil());
    return l10n?.ephemeralMinutesLeft(minutes) ?? '${minutes}m left';
  }
  if (remainingSeconds < 60 * 60 * 24) {
    final hours = math.max(1, (remainingSeconds / (60 * 60)).ceil());
    return l10n?.ephemeralHoursLeft(hours) ?? '${hours}h left';
  }
  final days = math.max(1, (remainingSeconds / (60 * 60 * 24)).ceil());
  return l10n?.ephemeralDaysLeft(days) ?? '${days}d left';
}

String formatVerboseRemaining(
  int remainingSeconds, {
  AppLocalizations? l10n,
}) {
  if (remainingSeconds <= 0) return l10n?.timeNow ?? 'now';
  if (remainingSeconds <= 60) {
    return l10n?.ephemeralInOneMinute ?? 'in 1 minute';
  }
  if (remainingSeconds < 60 * 60) {
    final minutes = math.max(1, (remainingSeconds / 60).ceil());
    return l10n?.ephemeralInMinutes(minutes) ??
        'in $minutes minute${minutes == 1 ? '' : 's'}';
  }
  if (remainingSeconds < 60 * 60 * 24) {
    final hours = math.max(1, (remainingSeconds / (60 * 60)).ceil());
    return l10n?.ephemeralInHours(hours) ??
        'in $hours hour${hours == 1 ? '' : 's'}';
  }
  final days = math.max(1, (remainingSeconds / (60 * 60 * 24)).ceil());
  return l10n?.ephemeralInDays(days) ??
      'in $days day${days == 1 ? '' : 's'}';
}

String formatCompactTtl(int ttlSeconds, {AppLocalizations? l10n}) {
  if (ttlSeconds < 60) {
    final seconds = math.max(1, ttlSeconds);
    return l10n?.ephemeralSeconds(seconds) ?? '${seconds}s TTL';
  }
  if (ttlSeconds < 60 * 60) {
    final minutes = math.max(1, (ttlSeconds / 60).ceil());
    return l10n?.ephemeralMinutes(minutes) ?? '${minutes}m TTL';
  }
  if (ttlSeconds < 60 * 60 * 24) {
    final hours = math.max(1, (ttlSeconds / (60 * 60)).ceil());
    return l10n?.ephemeralHours(hours) ?? '${hours}h TTL';
  }
  final days = math.max(1, (ttlSeconds / (60 * 60 * 24)).ceil());
  return l10n?.ephemeralDays(days) ?? '${days}d TTL';
}

String formatVerboseTtl(int ttlSeconds, {AppLocalizations? l10n}) {
  if (ttlSeconds < 60) {
    final seconds = math.max(1, ttlSeconds);
    return l10n?.ephemeralSeconds(seconds) ??
        '$seconds second${seconds == 1 ? '' : 's'}';
  }
  if (ttlSeconds < 60 * 60) {
    final minutes = math.max(1, (ttlSeconds / 60).ceil());
    return l10n?.ephemeralMinutes(minutes) ??
        '$minutes minute${minutes == 1 ? '' : 's'}';
  }
  if (ttlSeconds < 60 * 60 * 24) {
    final hours = math.max(1, (ttlSeconds / (60 * 60)).ceil());
    return l10n?.ephemeralHours(hours) ??
        '$hours hour${hours == 1 ? '' : 's'}';
  }
  final days = math.max(1, (ttlSeconds / (60 * 60 * 24)).ceil());
  return l10n?.ephemeralDays(days) ??
      '$days day${days == 1 ? '' : 's'}';
}

String formatAbsoluteDeadline(DateTime deadline, {AppLocalizations? l10n}) {
  if (l10n != null) {
    return DateFormat.yMMMd(l10n.localeName).add_jm().format(deadline.toLocal());
  }
  const months = [
    'Jan',
    'Feb',
    'Mar',
    'Apr',
    'May',
    'Jun',
    'Jul',
    'Aug',
    'Sep',
    'Oct',
    'Nov',
    'Dec',
  ];
  final local = deadline.toLocal();
  final hour12 = local.hour % 12 == 0 ? 12 : local.hour % 12;
  final minute = local.minute.toString().padLeft(2, '0');
  final period = local.hour < 12 ? 'AM' : 'PM';
  return '${months[local.month - 1]} ${local.day}, $hour12:$minute $period';
}