import 'package:flutter/material.dart';
import '../main.dart';
import '../services/collection_service.dart';
import '../theme/app_colors.dart';

/// Screen to manage a collection: rename, invite/remove members, delete.
class ManageCollectionScreen extends StatefulWidget {
  final Collection collection;

  const ManageCollectionScreen({super.key, required this.collection});

  @override
  State<ManageCollectionScreen> createState() =>
      _ManageCollectionScreenState();
}

class _ManageCollectionScreenState extends State<ManageCollectionScreen> {
  late Collection _collection;
  List<CollectionMember> _members = [];
  bool _isLoading = true;
  bool _isInviting = false;

  @override
  void initState() {
    super.initState();
    _collection = widget.collection;
    _loadMembers();
  }

  Future<void> _loadMembers() async {
    setState(() => _isLoading = true);
    try {
      final members =
          await CollectionService.getMembers(_collection.id);
      if (!mounted) return;
      setState(() {
        _members = members;
        _isLoading = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() => _isLoading = false);
      showGlobalError(
        e,
        fallback: 'Failed to load members. Please try again.',
      );
    }
  }

  Future<void> _rename() async {
    final formKey = GlobalKey<FormState>();
    final ctrl = TextEditingController(text: _collection.name);
    final descCtrl =
        TextEditingController(text: _collection.description ?? '');

    final result = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('Rename Collection'),
        content: Form(
          key: formKey,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              TextFormField(
                controller: ctrl,
                autofocus: true,
                maxLength: 50,
                decoration: const InputDecoration(labelText: 'Name'),
                validator: (value) {
                  final trimmed = value?.trim() ?? '';
                  if (trimmed.isEmpty) return 'Name is required';
                  if (trimmed.length < 2) return 'Name must be at least 2 characters';
                  if (trimmed.length > 50) return 'Name must be 50 characters or fewer';
                  return null;
                },
              ),
              const SizedBox(height: 12),
              TextField(
                controller: descCtrl,
                decoration:
                    const InputDecoration(labelText: 'Description (optional)'),
              ),
            ],
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () {
              if (formKey.currentState!.validate()) {
                Navigator.pop(context, true);
              }
            },
            child: const Text('Save'),
          ),
        ],
      ),
    );

    if (result != true) return;

    final trimmedDesc = descCtrl.text.trim();
    final String? description =
        trimmedDesc.isEmpty ? null : trimmedDesc;

    try {
      await CollectionService.update(
        collectionId: _collection.id,
        name: ctrl.text.trim(),
        description: description,
      );
      setState(() {
        _collection = Collection(
          id: _collection.id,
          name: ctrl.text.trim(),
          description: description,
          ownerId: _collection.ownerId,
          createdAt: _collection.createdAt,
          role: _collection.role,
          itemCount: _collection.itemCount,
          memberCount: _collection.memberCount,
        );
      });
      showGlobalSuccess('Collection renamed!');
    } catch (e) {
      showGlobalError(
        e,
        fallback: 'Could not rename collection. Please try again.',
      );
    }
  }

  Future<void> _inviteMember() async {
    if (_isInviting) return;
    final emailCtrl = TextEditingController();
    String inviteRole = 'member';

    final result = await showDialog<bool>(
      context: context,
      builder: (_) => StatefulBuilder(
        builder: (context, setSheetState) => AlertDialog(
        icon: Container(
          padding: const EdgeInsets.all(12),
          decoration: const BoxDecoration(
            gradient: AppColors.brandGradient,
            shape: BoxShape.circle,
          ),
          child: const Icon(Icons.person_add, color: Colors.white, size: 28),
        ),
        title: const Text('Invite Member'),
        content: SingleChildScrollView(
          child: ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 420),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const Text(
                  'Enter the email address of the person you want to invite. '
                  'They must already have an account.',
                  style: TextStyle(
                    fontSize: 13,
                    color: AppColors.textSecondary,
                  ),
                ),
                const SizedBox(height: 16),
                TextField(
                  controller: emailCtrl,
                  autofocus: true,
                  keyboardType: TextInputType.emailAddress,
                  decoration: const InputDecoration(
                    labelText: 'Email address',
                    hintText: 'user@example.com',
                    prefixIcon: Icon(Icons.email_outlined),
                  ),
                ),
                const SizedBox(height: 12),
                DropdownButtonFormField<String>(
                  isExpanded: true,
                  value: inviteRole,
                  decoration: const InputDecoration(
                    labelText: 'Role',
                    prefixIcon: Icon(Icons.security_outlined),
                  ),
                  items: const [
                    DropdownMenuItem(value: 'member', child: Text('Member')),
                    DropdownMenuItem(value: 'viewer', child: Text('Viewer')),
                  ],
                  onChanged: (value) {
                    if (value == null) return;
                    setSheetState(() => inviteRole = value);
                  },
                ),
                const SizedBox(height: 8),
                Align(
                  alignment: Alignment.centerLeft,
                  child: Text(
                    inviteRole == 'viewer'
                        ? 'Viewer: read-only access.'
                        : 'Member: can add, copy, edit, and remove cars.',
                    style: const TextStyle(
                      fontSize: 12,
                      color: AppColors.textSecondary,
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () {
              if (emailCtrl.text.trim().isEmpty) return;
              Navigator.pop(context, true);
            },
            child: const Text('Invite'),
          ),
        ],
        ),
      ),
    );

    if (result != true) return;

    final email = emailCtrl.text.trim();
    final emailRegex = RegExp(r'^[^@\s]+@[^@\s]+\.[^@\s]+$');
    if (!emailRegex.hasMatch(email)) {
      showGlobalSnackBar('Please enter a valid email address.', isError: true);
      return;
    }

    try {
      setState(() => _isInviting = true);
      await CollectionService.inviteByEmail(
        collectionId: _collection.id,
        email: email,
        role: inviteRole,
      );
      showGlobalSuccess(
        inviteRole == 'viewer' ? 'Viewer invited!' : 'Member invited!',
      );
      await _loadMembers();
    } catch (e) {
      showGlobalError(
        e,
        fallback: 'Could not send invitation. Please try again.',
      );
    } finally {
      if (mounted) setState(() => _isInviting = false);
    }
  }

  Future<void> _removeMember(CollectionMember member) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('Remove Member?'),
        content: Text(
            'Remove ${member.email} from this collection?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, true),
            style: ElevatedButton.styleFrom(backgroundColor: AppColors.error),
            child: const Text('Remove'),
          ),
        ],
      ),
    );

    if (confirmed != true) return;

    try {
      await CollectionService.removeMember(
        collectionId: _collection.id,
        memberUserId: member.userId,
      );
      showGlobalSuccess('Member removed.');
      await _loadMembers();
    } catch (e) {
      showGlobalError(
        e,
        fallback: 'Could not remove member. Please try again.',
      );
    }
  }

  Future<void> _leaveCollection() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('Leave Collection?'),
        content: Text(
            'You will lose access to "${_collection.name}". '
            'This action cannot be undone.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, true),
            style: ElevatedButton.styleFrom(backgroundColor: AppColors.error),
            child: const Text('Leave'),
          ),
        ],
      ),
    );

    if (confirmed != true) return;

    try {
      await CollectionService.leave(_collection.id);
      showGlobalSuccess('Left "${_collection.name}".');
      if (mounted) Navigator.pop(context);
    } catch (e) {
      showGlobalError(
        e,
        fallback: 'Could not leave collection. Please try again.',
      );
    }
  }

  Future<void> _deleteCollection() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: const Text('Delete Collection?'),
        content: Text(
            'Delete "${_collection.name}" and ALL its items? '
            'This cannot be undone.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, true),
            style: ElevatedButton.styleFrom(backgroundColor: AppColors.error),
            child: const Text('Delete Forever'),
          ),
        ],
      ),
    );

    if (confirmed != true) return;

    try {
      await CollectionService.delete(_collection.id);
      showGlobalSuccess('Collection deleted.');
      if (mounted) Navigator.pop(context);
    } catch (e) {
      showGlobalError(
        e,
        fallback: 'Could not delete collection. Please try again.',
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final currentUserId = supabase.auth.currentUser?.id;

    return Scaffold(
      appBar: AppBar(
        title: Text(_collection.name),
        actions: [
          if (_collection.isOwner)
            IconButton(
              icon: const Icon(Icons.edit),
              tooltip: 'Rename',
              onPressed: _rename,
            ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: _loadMembers,
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            if (_collection.description != null &&
                _collection.description!.isNotEmpty) ...[
              Text(
                _collection.description!,
                style: const TextStyle(
                    fontSize: 14, color: AppColors.textSecondary),
              ),
              const SizedBox(height: 16),
            ],

            Row(
              children: [
                Text(
                  'Members',
                  style: theme.textTheme.titleMedium?.copyWith(
                    fontWeight: FontWeight.w600,
                  ),
                ),
                const Spacer(),
                if (_collection.isOwner)
                  TextButton.icon(
                    onPressed: _isInviting ? null : _inviteMember,
                    icon: const Icon(Icons.person_add, size: 18),
                    label: Text(_isInviting ? 'Inviting…' : 'Invite'),
                  ),
              ],
            ),
            const SizedBox(height: 8),

            if (_isLoading)
              const Center(
                child: Padding(
                  padding: EdgeInsets.all(24),
                  child: CircularProgressIndicator(),
                ),
              )
            else
              ...List.generate(_members.length, (i) {
                final member = _members[i];
                return Card(
                  margin: const EdgeInsets.only(bottom: 8),
                  child: ListTile(
                    leading: CircleAvatar(
                      backgroundColor:
                          member.isOwner ? AppColors.orange : AppColors.navy,
                      child: Icon(
                        member.isOwner ? Icons.star : Icons.person,
                        color: Colors.white,
                        size: 20,
                      ),
                    ),
                    title: Text(
                      member.email,
                      style: const TextStyle(fontWeight: FontWeight.w500),
                    ),
                    subtitle: Text(
                      _roleLabel(member.role),
                      style: const TextStyle(fontSize: 12),
                    ),
                    trailing: (!member.isOwner &&
                            _collection.isOwner &&
                            member.userId != currentUserId)
                        ? IconButton(
                            icon: const Icon(Icons.remove_circle_outline,
                                color: AppColors.error),
                            onPressed: () => _removeMember(member),
                          )
                        : null,
                  ),
                );
              }),

            const SizedBox(height: 32),
            const Divider(),
            const SizedBox(height: 16),

            Text(
              'Danger Zone',
              style: theme.textTheme.titleMedium?.copyWith(
                fontWeight: FontWeight.w600,
                color: AppColors.error,
              ),
            ),
            const SizedBox(height: 12),

            if (!_collection.isOwner)
              SizedBox(
                width: double.infinity,
                child: OutlinedButton.icon(
                  onPressed: _leaveCollection,
                  icon: const Icon(Icons.exit_to_app, color: AppColors.error),
                  label: const Text('Leave Collection',
                      style: TextStyle(color: AppColors.error)),
                  style: OutlinedButton.styleFrom(
                    side: const BorderSide(color: AppColors.error),
                    padding: const EdgeInsets.symmetric(vertical: 14),
                  ),
                ),
              )
            else ...[
              const Text(
                'As owner, you cannot leave this collection. You can delete it instead.',
                style: TextStyle(
                  fontSize: 12,
                  color: AppColors.textSecondary,
                ),
              ),
              const SizedBox(height: 10),
              SizedBox(
                width: double.infinity,
                child: OutlinedButton.icon(
                  onPressed: _deleteCollection,
                  icon: const Icon(Icons.delete_forever,
                      color: AppColors.error),
                  label: const Text('Delete Collection',
                      style: TextStyle(color: AppColors.error)),
                  style: OutlinedButton.styleFrom(
                    side: const BorderSide(color: AppColors.error),
                    padding: const EdgeInsets.symmetric(vertical: 14),
                  ),
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }

  String _roleLabel(String role) {
    switch (role) {
      case 'owner':
        return 'Owner';
      case 'viewer':
        return 'Viewer (read-only)';
      default:
        return 'Member';
    }
  }
}