import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:image_picker/image_picker.dart';
import 'package:intl/intl.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';

import '../core/theme.dart';
import '../core/permissions.dart';
import '../models/compliance.dart';
import '../state/compliance_controller.dart';
import '../state/session_controller.dart';
import '../widgets/common.dart';

IconData _sectionIcon(ComplianceSection s) => switch (s) {
  ComplianceSection.documents => LucideIcons.fileText,
  ComplianceSection.certificates => LucideIcons.award,
  ComplianceSection.taxForms => LucideIcons.receipt,
  ComplianceSection.wardrobe => LucideIcons.shirt,
};

ChipTone _toneFor(ComplianceState state) => switch (state) {
  ComplianceState.verified => ChipTone.neutral,
  ComplianceState.pending => ChipTone.blue,
  ComplianceState.missing => ChipTone.yellow,
};

/// Everything a business must see before you can work.
class ComplianceHubScreen extends ConsumerWidget {
  const ComplianceHubScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final (done, total) = ref.watch(complianceProgressProvider);
    final remaining = total - done;

    return Scaffold(
      body: ListView(
        padding: EdgeInsets.zero,
        children: [
          BrandHeader(
            padding: const EdgeInsets.fromLTRB(20, 8, 20, 22),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    HeaderIconButton(
                      icon: LucideIcons.arrowLeft,
                      onPressed: () => context.pop(),
                    ),
                    StatusChip(
                      remaining == 0 ? 'All clear' : '$remaining left',
                      tone: remaining == 0 ? ChipTone.neutral : ChipTone.yellow,
                    ),
                  ],
                ),
                const SizedBox(height: 18),
                const Text(
                  'Compliance',
                  style: TextStyle(
                    fontSize: 27,
                    fontWeight: FontWeight.w700,
                    letterSpacing: -0.9,
                    color: Colors.white,
                  ),
                ),
                const SizedBox(height: 5),
                Text(
                  'Everything a business must see before you work.',
                  style: TextStyle(
                    fontSize: 13.5,
                    color: Colors.white.withValues(alpha: 0.6),
                  ),
                ),
              ],
            ),
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(20, 18, 20, 28),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                KrowCard(
                  child: Column(
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          const Text(
                            'Overall',
                            style: TextStyle(
                              fontSize: 14.5,
                              fontWeight: FontWeight.w600,
                            ),
                          ),
                          Text(
                            '$done of $total',
                            style: const TextStyle(
                              fontSize: 14,
                              fontWeight: FontWeight.w700,
                            ),
                          ),
                        ],
                      ),
                      const SizedBox(height: 11),
                      KrowProgressBar(
                        total == 0 ? 1 : done / total,
                        color: done == total
                            ? KrowPalette.blue
                            : KrowPalette.yellow,
                      ),
                    ],
                  ),
                ),
                const SectionLabel('Sections'),
                TileGroup(
                  children: [
                    for (final section in ComplianceSection.values)
                      Consumer(
                        builder: (context, ref, _) {
                          final (d, t) = ref.watch(
                            sectionProgressProvider(section),
                          );
                          return NavTile(
                            icon: _sectionIcon(section),
                            title: section.title,
                            subtitle: section.subtitle,
                            badge: StatusChip(
                              '$d of $t',
                              tone: d == t ? ChipTone.neutral : ChipTone.yellow,
                            ),
                            onTap: () =>
                                context.push('/compliance/${section.name}'),
                          );
                        },
                      ),
                  ],
                ),
                const SizedBox(height: 16),
                const InfoBanner(
                  'Documents are shared with a business only when you accept '
                  'one of their shifts.',
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

/// One compliance section: documents, certificates, tax forms or attire.
class ComplianceListScreen extends ConsumerStatefulWidget {
  const ComplianceListScreen({super.key, required this.section});

  final ComplianceSection section;

  @override
  ConsumerState<ComplianceListScreen> createState() =>
      _ComplianceListScreenState();
}

class _ComplianceListScreenState extends ConsumerState<ComplianceListScreen> {
  String _filter = 'All';
  String _query = '';

  static const _filters = ['All', 'Verified', 'Pending', 'Missing'];

  @override
  Widget build(BuildContext context) {
    var items = ref.watch(complianceProvider).section(widget.section);
    final (done, total) = ref.watch(sectionProgressProvider(widget.section));

    if (_query.isNotEmpty) {
      final q = _query.toLowerCase();
      items = items.where((i) => i.title.toLowerCase().contains(q)).toList();
    }
    items = switch (_filter) {
      'Verified' =>
        items.where((i) => i.state == ComplianceState.verified).toList(),
      'Pending' =>
        items.where((i) => i.state == ComplianceState.pending).toList(),
      'Missing' =>
        items.where((i) => i.state == ComplianceState.missing).toList(),
      _ => items,
    };

    final required = items.where((i) => i.required_).toList();
    final optional = items.where((i) => !i.required_).toList();

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.section.title),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: 16),
            child: Center(
              child: StatusChip(
                '$done of $total',
                tone: done == total ? ChipTone.neutral : ChipTone.yellow,
              ),
            ),
          ),
        ],
      ),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(20, 8, 20, 28),
        children: [
          TextField(
            onChanged: (v) => setState(() => _query = v),
            decoration: InputDecoration(
              hintText: 'Search ${widget.section.title.toLowerCase()}',
              prefixIcon: const Icon(LucideIcons.search, size: 18),
            ),
          ),
          const SizedBox(height: 14),
          SingleChildScrollView(
            scrollDirection: Axis.horizontal,
            child: Row(
              children: [
                for (final f in _filters)
                  Padding(
                    padding: const EdgeInsets.only(right: 8),
                    child: ChoiceChip(
                      label: Text(f),
                      selected: f == _filter,
                      showCheckmark: false,
                      selectedColor: KrowPalette.blue,
                      labelStyle: TextStyle(
                        fontSize: 12.5,
                        fontWeight: FontWeight.w500,
                        color: f == _filter ? Colors.white : KrowPalette.mute,
                      ),
                      onSelected: (_) => setState(() => _filter = f),
                    ),
                  ),
              ],
            ),
          ),
          if (required.isNotEmpty) ...[
            const SectionLabel('Required'),
            TileGroup(
              children: [
                for (final item in required)
                  _ItemTile(section: widget.section, item: item),
              ],
            ),
          ],
          if (optional.isNotEmpty) ...[
            const SectionLabel('Unlocks more shifts'),
            TileGroup(
              children: [
                for (final item in optional)
                  _ItemTile(section: widget.section, item: item),
              ],
            ),
          ],
          if (required.isEmpty && optional.isEmpty)
            const Padding(
              padding: EdgeInsets.only(top: 24),
              child: EmptyState(
                icon: LucideIcons.search,
                title: 'Nothing here',
                message: 'Try a different filter.',
              ),
            ),
        ],
      ),
    );
  }
}

class _ItemTile extends StatelessWidget {
  const _ItemTile({required this.section, required this.item});

  final ComplianceSection section;
  final ComplianceItem item;

  @override
  Widget build(BuildContext context) {
    return NavTile(
      icon: _sectionIcon(section),
      title: item.title,
      subtitle: item.subtitle,
      badge: StatusChip(item.badge, tone: _toneFor(item.state)),
      onTap: () => context.push('/compliance/${section.name}/${item.id}'),
    );
  }
}

/// A single item: the file on record, its expiry, and the actions on it.
class ComplianceDetailScreen extends ConsumerWidget {
  const ComplianceDetailScreen({
    super.key,
    required this.section,
    required this.itemId,
  });

  final ComplianceSection section;
  final String itemId;

  /// Picks a real file: the camera for a new photo, the gallery for an
  /// existing one. Camera access is requested first, because image_picker
  /// surfaces a refusal as a plain null and the worker would be left tapping a
  /// button that silently does nothing.
  Future<void> _upload(BuildContext context, WidgetRef ref) async {
    final source = await showModalBottomSheet<ImageSource>(
      context: context,
      showDragHandle: true,
      builder: (context) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(LucideIcons.camera),
              title: const Text('Take a photo'),
              subtitle: const Text('It has to be the real item, worn by you'),
              onTap: () => Navigator.pop(context, ImageSource.camera),
            ),
            ListTile(
              leading: const Icon(LucideIcons.image),
              title: const Text('Choose from library'),
              onTap: () => Navigator.pop(context, ImageSource.gallery),
            ),
          ],
        ),
      ),
    );
    if (source == null || !context.mounted) return;

    if (source == ImageSource.camera) {
      final granted = await ref
          .read(sessionProvider.notifier)
          .request(AppPermission.camera);
      if (!context.mounted) return;
      if (!granted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: const Text('Camera access is off'),
            action: SnackBarAction(
              label: 'Settings',
              onPressed: ref.read(permissionServiceProvider).openSettings,
            ),
          ),
        );
        return;
      }
    }

    final XFile? picked;
    try {
      picked = await ImagePicker().pickImage(
        source: source,
        // Documents only need to be legible, and a full-resolution phone
        // photo is a slow upload on a venue's wifi.
        maxWidth: 2000,
        imageQuality: 85,
      );
    } on PlatformException catch (error) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Could not open: ${error.code}')));
      return;
    }
    // Null means the picker was dismissed, which is not an error.
    if (picked == null || !context.mounted) return;

    final size = await picked.length();
    if (!context.mounted) return;
    ref
        .read(complianceProvider.notifier)
        .uploadFile(
          section,
          itemId,
          picked.name,
          meta: '${(size / 1024 / 1024).toStringAsFixed(1)} MB · just now',
        );
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(const SnackBar(content: Text('Uploaded - sent for review')));
  }

  Future<void> _remove(BuildContext context, WidgetRef ref) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Remove this file?'),
        content: const Text(
          'Your account goes on hold for anything that needs it until a '
          'replacement is verified.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Keep it'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            style: FilledButton.styleFrom(minimumSize: const Size(0, 44)),
            child: const Text('Remove'),
          ),
        ],
      ),
    );
    if (ok != true || !context.mounted) return;
    ref.read(complianceProvider.notifier).removeFile(section, itemId);
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(const SnackBar(content: Text('File removed')));
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    ref.watch(complianceProvider);
    final item = ref.read(complianceProvider.notifier).find(section, itemId);
    if (item == null) {
      return Scaffold(
        appBar: AppBar(),
        body: const Center(child: Text('Item not found.')),
      );
    }
    final d = DateFormat('d MMM yyyy');

    return Scaffold(
      appBar: AppBar(
        title: Text(section.title),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: 16),
            child: Center(
              child: StatusChip(item.badge, tone: _toneFor(item.state)),
            ),
          ),
        ],
      ),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(20, 8, 20, 28),
        children: [
          Text(
            item.title,
            style: const TextStyle(
              fontSize: 26,
              fontWeight: FontWeight.w700,
              letterSpacing: -0.9,
            ),
          ),
          const SizedBox(height: 6),
          Text(
            item.subtitle,
            style: const TextStyle(fontSize: 13.5, color: KrowPalette.mute),
          ),
          if (section == ComplianceSection.wardrobe) ...[
            const SizedBox(height: 16),
            const InfoBanner(
              'The photo has to be you wearing the item. Catalogue shots and '
              'images pulled from the web get rejected.',
              warning: true,
            ),
          ],
          const SectionLabel('File on record'),
          if (item.fileName == null)
            EmptyState(
              icon: LucideIcons.upload,
              title: 'Nothing uploaded',
              message: 'JPEG, PNG or PDF, up to 10 MB.',
              action: FilledButton.icon(
                onPressed: () => _upload(context, ref),
                icon: const Icon(LucideIcons.plus, size: 18),
                label: const Text('Add a file'),
              ),
            )
          else
            KrowCard(
              padding: const EdgeInsets.all(14),
              child: Row(
                children: [
                  Container(
                    width: 44,
                    height: 44,
                    decoration: BoxDecoration(
                      color: const Color(0xFFDEEBE2),
                      borderRadius: BorderRadius.circular(10),
                    ),
                    child: const Icon(
                      LucideIcons.fileText,
                      size: 20,
                      color: Color(0xFF949FA5),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          item.fileName!,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: const TextStyle(
                            fontSize: 12.5,
                            fontWeight: FontWeight.w600,
                          ),
                        ),
                        const SizedBox(height: 3),
                        Text(
                          item.fileMeta ?? '',
                          style: const TextStyle(
                            fontSize: 11.5,
                            color: Color(0xFF949FA5),
                          ),
                        ),
                      ],
                    ),
                  ),
                  IconButton(
                    onPressed: () => ScaffoldMessenger.of(context).showSnackBar(
                      const SnackBar(content: Text('Preview opens the file')),
                    ),
                    icon: const Icon(LucideIcons.eye, size: 18),
                  ),
                ],
              ),
            ),
          const SectionLabel('Details'),
          KrowCard(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Column(
              children: [
                DetailRow('Status', item.badge),
                const Divider(height: 1),
                _ExpiryRow(section: section, item: item, format: d),
                const Divider(height: 1),
                const DetailRow('Shared with', '2 businesses'),
              ],
            ),
          ),
          const SizedBox(height: 16),
          InfoBanner(
            item.required_
                ? 'Removing this puts your account on hold until a new file is '
                      'verified. You cannot work in the meantime.'
                : 'Optional, but adding it opens up more shifts near you.',
          ),
          const SizedBox(height: 22),
          Row(
            children: [
              if (item.fileName != null) ...[
                Expanded(
                  child: OutlinedButton.icon(
                    onPressed: () => _remove(context, ref),
                    icon: const Icon(LucideIcons.trash2, size: 18),
                    label: const Text('Remove'),
                  ),
                ),
                const SizedBox(width: 10),
              ],
              Expanded(
                child: FilledButton.icon(
                  onPressed: () => _upload(context, ref),
                  icon: const Icon(LucideIcons.camera, size: 18),
                  label: Text(item.fileName == null ? 'Upload' : 'Replace'),
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class _ExpiryRow extends ConsumerWidget {
  const _ExpiryRow({
    required this.section,
    required this.item,
    required this.format,
  });

  final ComplianceSection section;
  final ComplianceItem item;
  final DateFormat format;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return InkWell(
      onTap: () async {
        final now = DateTime.now();
        final picked = await showDatePicker(
          context: context,
          initialDate: item.expires ?? now.add(const Duration(days: 365)),
          firstDate: now,
          lastDate: DateTime(now.year + 20),
        );
        if (picked == null) return;
        ref
            .read(complianceProvider.notifier)
            .setExpiry(section, item.id, picked);
      },
      child: DetailRow(
        'Expires',
        item.expires == null ? 'Tap to set' : format.format(item.expires!),
        valueColor: item.expires == null ? KrowPalette.blue : null,
      ),
    );
  }
}