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

import '../../core/exceptions.dart';
import '../../data/models/project.dart';
import '../../providers/projects_provider.dart';

class ProjectListScreen extends ConsumerWidget {
  const ProjectListScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final projectsAsync = ref.watch(projectsProvider);

    return Scaffold(
      appBar: AppBar(title: const Text('Projects')),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _showCreateDialog(context, ref),
        tooltip: 'New project',
        child: const Icon(Icons.add),
      ),
      body: projectsAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (e, _) => Center(child: Text('Error: $e')),
        data: (projects) {
          if (projects.isEmpty) {
            return const Center(
              child: Text(
                'No projects yet.\nTap + to create one.',
                textAlign: TextAlign.center,
              ),
            );
          }
          final active =
              projects.where((p) => p.status == 'active').toList();
          final other =
              projects.where((p) => p.status != 'active').toList();
          return ListView(
            padding: const EdgeInsets.symmetric(vertical: 8),
            children: [
              if (active.isNotEmpty) ...[
                _SectionHeader(title: 'Active (${active.length})'),
                ...active.map((p) => _ProjectTile(project: p)),
              ],
              if (other.isNotEmpty) ...[
                _SectionHeader(title: 'Other'),
                ...other.map((p) => _ProjectTile(project: p)),
              ],
            ],
          );
        },
      ),
    );
  }

  void _showCreateDialog(BuildContext context, WidgetRef ref) {
    showDialog<void>(
      context: context,
      builder: (dialogContext) => _CreateProjectDialog(
        onCreate: (title, description, goal) async {
          try {
            await ref
                .read(projectsProvider.notifier)
                .create(title: title, description: description, goal: goal);
          } on AppException catch (e) {
            if (context.mounted) {
              ScaffoldMessenger.of(context).showSnackBar(
                SnackBar(content: Text(e.message)),
              );
            }
          }
        },
      ),
    );
  }
}

class _SectionHeader extends StatelessWidget {
  final String title;
  const _SectionHeader({required this.title});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 4),
      child: Text(
        title,
        style: Theme.of(context)
            .textTheme
            .labelMedium
            ?.copyWith(color: Theme.of(context).colorScheme.primary),
      ),
    );
  }
}

class _ProjectTile extends ConsumerWidget {
  final Project project;
  const _ProjectTile({required this.project});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final statusColor = switch (project.status) {
      'completed' => Colors.green,
      'archived' => Colors.grey,
      _ => Theme.of(context).colorScheme.primary,
    };

    return ListTile(
      leading: CircleAvatar(
        backgroundColor: statusColor.withValues(alpha: 0.15),
        child: Icon(Icons.folder_outlined, color: statusColor, size: 20),
      ),
      title: Text(project.title),
      subtitle: project.description != null && project.description!.isNotEmpty
          ? Text(
              project.description!,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
            )
          : null,
      trailing: _StatusChip(status: project.status),
      onLongPress: () => _showOptions(context, ref),
    );
  }

  void _showOptions(BuildContext context, WidgetRef ref) {
    showModalBottomSheet<void>(
      context: context,
      builder: (_) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.check_circle_outline),
              title: const Text('Mark completed'),
              onTap: () async {
                Navigator.pop(context);
                await ref.read(projectsProvider.notifier).updateProject(
                  project.id,
                  {'status': 'completed'},
                );
              },
            ),
            ListTile(
              leading: const Icon(Icons.archive_outlined),
              title: const Text('Archive'),
              onTap: () async {
                Navigator.pop(context);
                await ref.read(projectsProvider.notifier).updateProject(
                  project.id,
                  {'status': 'archived'},
                );
              },
            ),
            ListTile(
              leading: Icon(Icons.delete_outline,
                  color: Theme.of(context).colorScheme.error),
              title: Text('Delete',
                  style: TextStyle(
                      color: Theme.of(context).colorScheme.error)),
              onTap: () async {
                Navigator.pop(context);
                final confirm = await showDialog<bool>(
                  context: context,
                  builder: (dialogContext) => AlertDialog(
                    title: const Text('Delete project?'),
                    content: Text(
                        'Notes and tasks will be unlinked, not deleted.'),
                    actions: [
                      TextButton(
                        onPressed: () =>
                            Navigator.pop(dialogContext, false),
                        child: const Text('Cancel'),
                      ),
                      TextButton(
                        onPressed: () =>
                            Navigator.pop(dialogContext, true),
                        child: const Text('Delete'),
                      ),
                    ],
                  ),
                );
                if (confirm == true && context.mounted) {
                  await ref
                      .read(projectsProvider.notifier)
                      .delete(project.id);
                }
              },
            ),
          ],
        ),
      ),
    );
  }
}

class _StatusChip extends StatelessWidget {
  final String status;
  const _StatusChip({required this.status});

  @override
  Widget build(BuildContext context) {
    final (label, color) = switch (status) {
      'completed' => ('Done', Colors.green),
      'archived' => ('Archived', Colors.grey),
      _ => ('Active', Theme.of(context).colorScheme.primary),
    };
    return Chip(
      label: Text(label, style: const TextStyle(fontSize: 11)),
      padding: EdgeInsets.zero,
      materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
      side: BorderSide(color: color.withValues(alpha: 0.4)),
      backgroundColor: color.withValues(alpha: 0.1),
      labelStyle: TextStyle(color: color),
    );
  }
}

class _CreateProjectDialog extends StatefulWidget {
  final Future<void> Function(String title, String? description, String? goal)
      onCreate;

  const _CreateProjectDialog({required this.onCreate});

  @override
  State<_CreateProjectDialog> createState() => _CreateProjectDialogState();
}

class _CreateProjectDialogState extends State<_CreateProjectDialog> {
  final _titleController = TextEditingController();
  final _descController = TextEditingController();
  final _goalController = TextEditingController();
  bool _saving = false;

  @override
  void dispose() {
    _titleController.dispose();
    _descController.dispose();
    _goalController.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    final title = _titleController.text.trim();
    if (title.isEmpty) return;
    setState(() => _saving = true);
    try {
      await widget.onCreate(
        title,
        _descController.text.trim().isEmpty ? null : _descController.text.trim(),
        _goalController.text.trim().isEmpty ? null : _goalController.text.trim(),
      );
      if (mounted) Navigator.pop(context);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('New Project'),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          TextField(
            controller: _titleController,
            decoration: const InputDecoration(
              labelText: 'Title',
              border: OutlineInputBorder(),
            ),
            autofocus: true,
            textInputAction: TextInputAction.next,
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _descController,
            decoration: const InputDecoration(
              labelText: 'Description (optional)',
              border: OutlineInputBorder(),
            ),
            maxLines: 2,
            textInputAction: TextInputAction.next,
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _goalController,
            decoration: const InputDecoration(
              labelText: 'Goal (optional)',
              border: OutlineInputBorder(),
            ),
            textInputAction: TextInputAction.done,
            onSubmitted: (_) => _submit(),
          ),
        ],
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: _saving ? null : _submit,
          child: _saving
              ? const SizedBox(
                  width: 16,
                  height: 16,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Text('Create'),
        ),
      ],
    );
  }
}