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

import '../controllers/biometric_controller.dart';

/// Opens the manual weight-entry dialog (Web/Desktop fallback path, also
/// available on mobile for offline logging).
///
/// Resolves to `true` when the sample was persisted, `false` when saving
/// failed, and `null` when the user dismissed the dialog.
Future<bool?> showLogWeightDialog(BuildContext context) {
  return showDialog<bool>(
    context: context,
    builder: (context) => const LogWeightDialog(),
  );
}

/// Form for logging a body-weight measurement without native health access.
class LogWeightDialog extends ConsumerStatefulWidget {
  const LogWeightDialog({super.key});

  @override
  ConsumerState<LogWeightDialog> createState() => _LogWeightDialogState();
}

class _LogWeightDialogState extends ConsumerState<LogWeightDialog> {
  late final TextEditingController _weightController = TextEditingController();
  late DateTime _measuredAt = DateTime.now();

  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  bool _isSaving = false;

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Log Weight'),
      content: SizedBox(
        width: 440,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                TextFormField(
                  controller: _weightController,
                  decoration: const InputDecoration(
                    labelText: 'Weight (lbs)',
                    border: OutlineInputBorder(),
                  ),
                  keyboardType: const TextInputType.numberWithOptions(
                    decimal: true,
                  ),
                  validator: (value) {
                    final parsed = double.tryParse((value ?? '').trim());
                    if (parsed == null || parsed <= 0) {
                      return 'Enter a valid weight';
                    }
                    return null;
                  },
                ),
                const SizedBox(height: 16),
                OutlinedButton.icon(
                  onPressed: _pickMeasuredAt,
                  icon: const Icon(Icons.calendar_today, size: 16),
                  label: Text('Measured: ${_formatDate(_measuredAt)}'),
                ),
              ],
            ),
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _isSaving ? null : () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          onPressed: _isSaving ? null : _save,
          icon: _isSaving
              ? const SizedBox(
                  width: 16,
                  height: 16,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Icon(Icons.monitor_weight_outlined),
          label: const Text('Save Weight'),
        ),
      ],
    );
  }

  String _formatDate(DateTime time) {
    const months = [
      'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
      'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
    ];
    return '${months[time.month - 1]} ${time.day}, ${time.year}';
  }

  Future<void> _pickMeasuredAt() async {
    final now = DateTime.now();
    final pickedDate = await showDatePicker(
      context: context,
      initialDate: _measuredAt,
      firstDate: DateTime(now.year - 5),
      lastDate: now,
    );
    if (pickedDate == null || !mounted) return;

    final pickedTime = await showTimePicker(
      context: context,
      initialTime: TimeOfDay.fromDateTime(_measuredAt),
    );
    if (!mounted) return;

    setState(() {
      _measuredAt = DateTime(
        pickedDate.year,
        pickedDate.month,
        pickedDate.day,
        pickedTime?.hour ?? _measuredAt.hour,
        pickedTime?.minute ?? _measuredAt.minute,
      );
    });
  }

  Future<void> _save() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;

    setState(() => _isSaving = true);
    final saved =
        await ref.read(biometricControllerProvider.notifier).logWeight(
              weightLbs: double.parse(_weightController.text.trim()),
              timestamp: _measuredAt,
            );
    if (!mounted) return;
    Navigator.of(context).pop(saved);
  }

  @override
  void dispose() {
    _weightController.dispose();
    super.dispose();
  }
}