import 'package:flutter/material.dart';
import '../models/models.dart';
import '../storage/local_storage.dart';
import '../theme.dart';
import 'about_screen.dart';
import 'saved_run_detail_screen.dart';

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

  @override
  State<SavedRunsScreen> createState() => _SavedRunsScreenState();
}

class _SavedRunsScreenState extends State<SavedRunsScreen> {
  List<SavedRun> _savedRuns = [];
  bool _loading = true;

  @override
  void initState() {
    super.initState();
    _loadSavedRuns();
  }

  Future<void> _loadSavedRuns() async {
    final runs = await LocalStorage.getSavedRuns();
    setState(() {
      _savedRuns = runs;
      _loading = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Saved Runs'),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          onPressed: () => Navigator.pop(context),
        ),
        actions: [
          IconButton(
            icon: const Icon(Icons.info_outline),
            onPressed: () => Navigator.push(
              context,
              MaterialPageRoute(builder: (_) => const AboutScreen()),
            ),
          ),
        ],
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : _savedRuns.isEmpty
              ? _buildEmptyState()
              : _buildRunsList(),
    );
  }

  Widget _buildEmptyState() {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.bookmark_outline,
              size: 64,
              color: AppColors.textSecondary.withAlpha(128),
            ),
            const SizedBox(height: 16),
            Text(
              'No saved runs yet',
              style: Theme.of(context).textTheme.titleMedium?.copyWith(
                    color: AppColors.textSecondary,
                  ),
            ),
            const SizedBox(height: 8),
            Text(
              'Save a calculation from the results screen to compare runs over time.',
              style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                    color: AppColors.textSecondary,
                  ),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildRunsList() {
    return ListView.builder(
      padding: const EdgeInsets.all(16),
      itemCount: _savedRuns.length,
      itemBuilder: (context, index) {
        final run = _savedRuns[index];
        return _buildRunCard(run);
      },
    );
  }

  Widget _buildRunCard(SavedRun run) {
    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      child: InkWell(
        onTap: () => _openRunDetail(run),
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Row(
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      run.label,
                      style: Theme.of(context).textTheme.titleMedium,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      run.displayDate,
                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
                            color: AppColors.textSecondary,
                          ),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      run.dominantFactorSummary,
                      style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                            color: AppColors.primary,
                          ),
                    ),
                  ],
                ),
              ),
              IconButton(
                icon: const Icon(Icons.delete_outline),
                color: AppColors.error,
                onPressed: () => _confirmDelete(run),
              ),
            ],
          ),
        ),
      ),
    );
  }

  void _openRunDetail(SavedRun run) async {
    await Navigator.push(
      context,
      MaterialPageRoute(
        builder: (_) => SavedRunDetailScreen(savedRun: run),
      ),
    );
    // Refresh list in case label was edited
    _loadSavedRuns();
  }

  void _confirmDelete(SavedRun run) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Delete Run?'),
        content: Text('Delete "${run.label}"? This cannot be undone.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () {
              Navigator.pop(context);
              _deleteRun(run);
            },
            style: TextButton.styleFrom(foregroundColor: AppColors.error),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
  }

  Future<void> _deleteRun(SavedRun run) async {
    await LocalStorage.deleteSavedRun(run.id);
    _loadSavedRuns();

    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Run deleted')),
      );
    }
  }
}