import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';

import '../models/source.dart';
import '../state/app_state.dart';

/// User-facing app name. Platform launcher labels (AndroidManifest, Info.plist,
/// web/manifest.json, windows/runner) are set separately.
const appName = 'Tagesbyte';

String timeAgo(DateTime? date) {
  if (date == null) return '';
  final diff = DateTime.now().difference(date.toLocal());
  if (diff.inMinutes < 1) return 'just now';
  if (diff.inMinutes < 60) return '${diff.inMinutes} min ago';
  if (diff.inHours < 24) return '${diff.inHours} h ago';
  if (diff.inDays == 1) return 'yesterday';
  return '${diff.inDays} days ago';
}

String formatDateTime(DateTime date) {
  final d = date.toLocal();
  String two(int n) => n.toString().padLeft(2, '0');
  return '${two(d.day)}.${two(d.month)}.${d.year} ${two(d.hour)}:${two(d.minute)}';
}

const weekdayNames = [
  'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday',
];

const monthNames = [
  'January', 'February', 'March', 'April', 'May', 'June',
  'July', 'August', 'September', 'October', 'November', 'December',
];

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

/// The line above the articles of [kind], e.g.
/// "12 articles · last 24 h · 3 paid/ads hidden".
String articleCountLine(AppState state, SourceKind kind) {
  final hidden = state.hiddenCountOf(kind);
  return '${state.articlesOf(kind).length} articles · last ${_windowLabel(state.windowOf(kind))}'
      '${hidden > 0 ? ' · $hidden paid/ads hidden' : ''}';
}

String _windowLabel(Duration window) =>
    window.inHours < 72 ? '${window.inHours} h' : '${window.inDays} days';

Future<void> openUrl(BuildContext context, String url) async {
  final ok = await launchUrl(Uri.parse(url), mode: LaunchMode.externalApplication);
  if (!ok && context.mounted) {
    ScaffoldMessenger.of(context)
        .showSnackBar(SnackBar(content: Text('Could not open $url')));
  }
}

/// App bar button that refreshes all Sources; off while a refresh runs.
class RefreshButton extends StatelessWidget {
  const RefreshButton({super.key, required this.state});

  final AppState state;

  @override
  Widget build(BuildContext context) => IconButton(
        tooltip: 'Refresh',
        onPressed: state.loading ? null : state.refresh,
        icon: const Icon(Icons.refresh),
      );
}

/// A scrollable [list] that refreshes all Sources when pulled down, under a
/// progress bar while a refresh runs and an optional [notice].
class RefreshableList extends StatelessWidget {
  const RefreshableList({super.key, required this.state, required this.list, this.notice});

  final AppState state;
  final Widget list;
  final Widget? notice;

  @override
  Widget build(BuildContext context) => Column(
        children: [
          if (state.loading) const LinearProgressIndicator(),
          if (notice != null) notice!,
          Expanded(child: RefreshIndicator(onRefresh: state.refresh, child: list)),
        ],
      );
}

/// Centered icon + text + optional action, used for empty and error states.
class EmptyState extends StatelessWidget {
  const EmptyState({
    super.key,
    required this.icon,
    required this.title,
    this.message,
    this.action,
  });

  final IconData icon;
  final String title;
  final String? message;
  final Widget? action;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(icon, size: 56, color: theme.colorScheme.primary),
            const SizedBox(height: 16),
            Text(title, style: theme.textTheme.titleMedium, textAlign: TextAlign.center),
            if (message != null) ...[
              const SizedBox(height: 8),
              Text(
                message!,
                style: theme.textTheme.bodyMedium
                    ?.copyWith(color: theme.colorScheme.onSurfaceVariant),
                textAlign: TextAlign.center,
              ),
            ],
            if (action != null) ...[const SizedBox(height: 20), action!],
          ],
        ),
      ),
    );
  }
}