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

import '../api.dart';
import '../player.dart';
import '../theme.dart';
import '../widgets.dart';

class OverviewScreen extends StatefulWidget {
  const OverviewScreen({super.key});

  @override
  State<OverviewScreen> createState() => _OverviewScreenState();
}

class _OverviewScreenState extends State<OverviewScreen> {
  late Future<(Map<String, int>, List<AdminTrack>)> _data = _load();

  Future<(Map<String, int>, List<AdminTrack>)> _load() async =>
      (await AdminApi.overview(), await AdminApi.recentPending());

  void _reload() => setState(() => _data = _load());

  @override
  Widget build(BuildContext context) => Loader(
        future: _data,
        onRetry: _reload,
        builder: (context, data) {
          final (n, pending) = data;
          final attention = [
            if (n['pending']! > 0)
              _Todo(Icons.hourglass_top, NkColors.sun, '${n['pending']} songs waiting for review',
                  'Listen, fix the details and approve them.', '/songs?show=pending'),
            if (n['applications']! > 0)
              _Todo(Icons.how_to_reg, NkColors.sun, '${n['applications']} creator applications',
                  'Check their links and ID, then approve or ask for more.', '/applications'),
            if (n['takedowns']! > 0)
              _Todo(Icons.report_outlined, NkColors.roofRed, '${n['takedowns']} open takedown requests',
                  'Handle these in Studio (takedown_requests) for now.', null),
            if (n['no_singer']! > 0)
              _Todo(Icons.mic_off_outlined, NkColors.info, '${n['no_singer']} songs without a singer',
                  'Credit the singers so listeners can find them.', '/songs?show=no_singer'),
            if (n['no_album']! > 0)
              _Todo(Icons.album_outlined, NkColors.info, '${n['no_album']} songs without an album',
                  'Group them into albums.', '/songs?show=no_album'),
            if (n['needs_changes']! > 0)
              _Todo(Icons.edit_note, NkColors.info, '${n['needs_changes']} songs marked "needs changes"',
                  'Follow up once they are fixed.', '/songs?show=needs_changes'),
            if (n['empty_albums']! > 0)
              _Todo(Icons.folder_off_outlined, NkColors.muted, '${n['empty_albums']} empty albums',
                  'Delete them or move songs in.', '/albums'),
          ];
          return RefreshIndicator(
            onRefresh: () async => _reload(),
            child: ListView(
              padding: const EdgeInsets.only(bottom: 32),
              children: [
                PageHeader('Overview', subtitle: 'The Nanga Kathai catalog at a glance', actions: [
                  IconButton(tooltip: 'Refresh', onPressed: _reload, icon: const Icon(Icons.refresh)),
                ]),
                Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 24),
                  child: Wrap(
                    spacing: 12,
                    runSpacing: 12,
                    children: [
                      _Stat('Live songs', n['approved']!, '/songs?show=live'),
                      _Stat('Waiting for review', n['pending']!, '/songs?show=pending', highlight: n['pending']! > 0),
                      _Stat('Hidden', n['hidden']!, '/songs?show=hidden'),
                      _Stat('All songs', n['songs']!, '/songs'),
                      _Stat('Albums', n['albums']!, '/albums'),
                      _Stat('Singers', n['singers']!, '/singers'),
                      _Stat('Listener accounts', n['listeners']!, null),
                    ],
                  ),
                ),
                const SizedBox(height: 28),
                _sectionTitle(context, 'Needs attention'),
                Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 24),
                  child: Card(
                    child: attention.isEmpty
                        ? const EmptyState('All clear. Nothing needs attention right now.',
                            icon: Icons.check_circle_outline)
                        : Column(
                            children: [
                              for (final (i, t) in attention.indexed) ...[
                                if (i > 0) const Divider(),
                                ListTile(
                                  leading: Icon(t.icon, color: t.color),
                                  title: Text(t.title, style: const TextStyle(fontWeight: FontWeight.w700)),
                                  subtitle: Text(t.hint),
                                  trailing: t.path == null ? null : const Icon(Icons.chevron_right),
                                  onTap: t.path == null ? null : () => context.go(t.path!),
                                ),
                              ],
                            ],
                          ),
                  ),
                ),
                if (pending.isNotEmpty) ...[
                  const SizedBox(height: 28),
                  _sectionTitle(context, 'Latest waiting for review'),
                  Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 24),
                    child: Card(
                      child: Column(
                        children: [
                          for (final t in pending)
                            ListTile(
                              leading: PlayButton(t),
                              title: Text(t.title),
                              subtitle: Text('${creditLine(t)} · ${t.albumTitle ?? 'No album'}'),
                              trailing: Text(formatDate(t.createdAt), style: Theme.of(context).textTheme.bodySmall),
                            ),
                          const Divider(),
                          TextButton(
                            onPressed: () => context.go('/songs?show=pending'),
                            child: const Text('Review all'),
                          ),
                        ],
                      ),
                    ),
                  ),
                ],
              ],
            ),
          );
        },
      );

  Widget _sectionTitle(BuildContext context, String text) => Padding(
        padding: const EdgeInsets.fromLTRB(24, 0, 24, 10),
        child: Text(text, style: Theme.of(context).textTheme.titleLarge),
      );
}

class _Todo {
  const _Todo(this.icon, this.color, this.title, this.hint, this.path);
  final IconData icon;
  final Color color;
  final String title;
  final String hint;
  final String? path;
}

class _Stat extends StatelessWidget {
  const _Stat(this.label, this.value, this.path, {this.highlight = false});

  final String label;
  final int value;
  final String? path;
  final bool highlight;

  @override
  Widget build(BuildContext context) => SizedBox(
        width: 180,
        child: Card(
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(16),
            side: BorderSide(color: highlight ? NkColors.sun : NkColors.outline),
          ),
          clipBehavior: Clip.antiAlias,
          child: InkWell(
            onTap: path == null ? null : () => context.go(path!),
            child: Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text('$value',
                      style: Theme.of(context)
                          .textTheme
                          .headlineMedium
                          ?.copyWith(color: highlight ? NkColors.sun : NkColors.cream)),
                  const SizedBox(height: 4),
                  Text(label, style: Theme.of(context).textTheme.bodySmall),
                ],
              ),
            ),
          ),
        ),
      );
}