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

import '../../app/theme.dart';
import '../../audio/player_providers.dart';
import '../../core/models.dart';
import '../../offline/download_store.dart';
import '../../shared/widgets/artwork.dart';
import '../../shared/widgets/section_header.dart';

/// Songs saved on this phone. Works with no internet: everything shown here
/// comes from the download index, not the server.
class DownloadsScreen extends ConsumerWidget {
  const DownloadsScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final d = ref.watch(downloadsProvider);
    final controller = ref.read(playerControllerProvider);
    final store = ref.read(downloadStoreProvider);
    final text = Theme.of(context).textTheme;
    final current = ref.watch(mediaItemProvider).value?.id;

    return SafeArea(
      bottom: false,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(18, 12, 8, 4),
            child: Row(
              children: [
                Expanded(child: Text('Downloads', style: text.headlineMedium)),
                if (d.entries.isNotEmpty)
                  PopupMenuButton<void>(
                    tooltip: 'More',
                    itemBuilder: (_) => [
                      PopupMenuItem<void>(
                        onTap: () => _confirmRemoveAll(context, store),
                        child: const Text('Remove all downloads'),
                      ),
                    ],
                  ),
              ],
            ),
          ),
          if (d.entries.isNotEmpty || d.progress.isNotEmpty)
            Padding(
              padding: const EdgeInsets.fromLTRB(18, 0, 18, 8),
              child: Row(
                children: [
                  Expanded(
                    child: Text(
                      '${d.entries.length} songs · ${_size(d.totalBytes)}'
                      '${d.progress.isEmpty ? '' : ' · ${d.progress.length} downloading'}',
                      style: const TextStyle(color: NkColors.muted),
                    ),
                  ),
                  if (d.entries.isNotEmpty) ...[
                    IconButton(
                      tooltip: 'Shuffle',
                      icon: const Icon(Icons.shuffle, color: NkColors.sun),
                      onPressed: () {
                        final list = [...d.entries]..shuffle();
                        controller.playDownloads(list);
                      },
                    ),
                    IconButton.filled(
                      tooltip: 'Play all',
                      onPressed: () => controller.playDownloads(d.entries),
                      icon: const Icon(Icons.play_arrow_rounded),
                    ),
                  ],
                ],
              ),
            ),
          Expanded(
            child: d.entries.isEmpty && d.progress.isEmpty
                ? const Center(
                    child: SingleChildScrollView(
                      child: EmptyState(
                        icon: Icons.download_for_offline_outlined,
                        title: 'No downloads yet',
                        message: 'Tap ⋮ on any song, or "Download album", to listen without signal in the hills. '
                            'Downloads play only inside Nanga Kathai.',
                      ),
                    ),
                  )
                : ListView(
                    padding: const EdgeInsets.fromLTRB(18, 0, 18, 24),
                    children: [
                      for (final p in d.progress.entries)
                        Padding(
                          padding: const EdgeInsets.symmetric(vertical: 6),
                          child: Row(
                            children: [
                              const SizedBox.square(
                                dimension: 52,
                                child: Center(child: Icon(Icons.downloading_rounded, color: NkColors.muted)),
                              ),
                              const SizedBox(width: 14),
                              Expanded(
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Text(p.value == 0 ? 'Waiting…' : 'Downloading ${(p.value * 100).round()}%',
                                        style: const TextStyle(color: NkColors.muted)),
                                    const SizedBox(height: 6),
                                    LinearProgressIndicator(value: p.value == 0 ? null : p.value),
                                  ],
                                ),
                              ),
                            ],
                          ),
                        ),
                      for (var i = 0; i < d.entries.length; i++)
                        _DownloadTile(
                          entry: d.entries[i],
                          isCurrent: d.entries[i].trackId == current,
                          onTap: () => controller.playDownloads(d.entries, index: i),
                          onRemove: () => store.remove(d.entries[i].trackId),
                        ),
                    ],
                  ),
          ),
        ],
      ),
    );
  }

  static String _size(int bytes) =>
      bytes >= 1 << 30 ? '${(bytes / (1 << 30)).toStringAsFixed(1)} GB' : '${(bytes / (1 << 20)).round()} MB';

  void _confirmRemoveAll(BuildContext context, DownloadStore store) {
    showDialog<void>(
      context: context,
      builder: (dialog) => AlertDialog(
        title: const Text('Remove all downloads?'),
        content: const Text('The songs stay in the app; you can download them again any time.'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(dialog), child: const Text('Cancel')),
          FilledButton(
            onPressed: () {
              store.removeAll();
              Navigator.pop(dialog);
            },
            child: const Text('Remove'),
          ),
        ],
      ),
    );
  }
}

class _DownloadTile extends StatelessWidget {
  const _DownloadTile({required this.entry, required this.isCurrent, required this.onTap, required this.onRemove});

  final DownloadEntry entry;
  final bool isCurrent;
  final VoidCallback onTap;
  final VoidCallback onRemove;

  @override
  Widget build(BuildContext context) {
    final text = Theme.of(context).textTheme;
    return InkWell(
      onTap: onTap,
      borderRadius: BorderRadius.circular(12),
      child: Padding(
        padding: const EdgeInsets.symmetric(vertical: 6),
        child: Row(
          children: [
            ClipRRect(
              borderRadius: BorderRadius.circular(10),
              child: SizedBox.square(
                dimension: 52,
                child: OccasionCover(occasion: Occasion.fromId(entry.occasion), size: 52),
              ),
            ),
            const SizedBox(width: 14),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(entry.title,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: text.titleMedium?.copyWith(color: isCurrent ? NkColors.sun : NkColors.cream)),
                  const SizedBox(height: 2),
                  Row(
                    children: [
                      const Icon(Icons.download_done_rounded, size: 16, color: NkColors.teaLeaf),
                      const SizedBox(width: 4),
                      Expanded(
                        child: Text(
                          '${entry.credit} · ${formatDuration(Duration(milliseconds: entry.durationMs))}',
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: text.bodyMedium?.copyWith(color: NkColors.muted),
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
            IconButton(
              tooltip: 'Remove download',
              icon: const Icon(Icons.delete_outline, color: NkColors.muted),
              onPressed: onRemove,
            ),
          ],
        ),
      ),
    );
  }
}