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

import '../../../../core/utils/date_time_utils.dart';
import '../../domain/entities/injection_site.dart';
import '../../domain/value_objects/glp1_compound.dart';
import '../controllers/medication_controller.dart';

/// Opens the interactive injection logging dialog.
///
/// Resolves to `true` when the injection was persisted, `false` when saving
/// failed, and `null` when the user dismissed the dialog.
Future<bool?> showLogInjectionDialog(
  BuildContext context, {
  Glp1Compound? initialCompound,
  InjectionSite? initialSite,
}) {
  return showDialog<bool>(
    context: context,
    builder: (context) => LogInjectionDialog(
      initialCompound: initialCompound,
      initialSite: initialSite,
    ),
  );
}

/// Form for logging a GLP-1 injection: compound, dosage, administration
/// timestamp, and the 12-quadrant rotation site selector.
class LogInjectionDialog extends ConsumerStatefulWidget {
  const LogInjectionDialog({
    super.key,
    this.initialCompound,
    this.initialSite,
  });

  /// Compound pre-selected from the latest logged dose.
  final Glp1Compound? initialCompound;

  /// Quadrant pre-selected from the rotation policy's suggestion.
  final InjectionSite? initialSite;

  @override
  ConsumerState<LogInjectionDialog> createState() => _LogInjectionDialogState();
}

class _LogInjectionDialogState extends ConsumerState<LogInjectionDialog> {
  late Glp1Compound _compound =
      widget.initialCompound ?? Glp1Compound.semaglutide;
  late InjectionSite _site =
      widget.initialSite ?? InjectionSite.abdomenRightUpper;
  late DateTime _administeredAt = DateTime.now();

  late final TextEditingController _doseController = TextEditingController(
    text: (widget.initialCompound ?? Glp1Compound.semaglutide)
        .defaultDoseMg
        .toString(),
  );
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  bool _isSaving = false;

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Log Injection'),
      content: SizedBox(
        width: 440,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                DropdownButtonFormField<Glp1Compound>(
                  initialValue: _compound,
                  // Long labels ("Tirzepatide (Mounjaro / Zepbound)") must
                  // ellipsize in the narrow mobile dialog instead of
                  // overflowing the selected-item row.
                  isExpanded: true,
                  decoration: const InputDecoration(
                    labelText: 'Compound',
                    border: OutlineInputBorder(),
                  ),
                  items: [
                    for (final compound in Glp1Compound.values)
                      DropdownMenuItem(
                        value: compound,
                        child: Text(
                          '${compound.displayName} (${compound.brandNames})',
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                  ],
                  onChanged: (compound) {
                    if (compound == null) return;
                    setState(() {
                      _compound = compound;
                      _doseController.text = compound.defaultDoseMg.toString();
                    });
                  },
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _doseController,
                  keyboardType:
                      const TextInputType.numberWithOptions(decimal: true),
                  decoration: const InputDecoration(
                    labelText: 'Dosage (mg)',
                    border: OutlineInputBorder(),
                    suffixText: 'mg',
                  ),
                  validator: (value) {
                    final dose = double.tryParse(value?.trim() ?? '');
                    if (dose == null || dose <= 0) {
                      return 'Enter a positive dose in mg';
                    }
                    return null;
                  },
                ),
                const SizedBox(height: 16),
                ListTile(
                  contentPadding: EdgeInsets.zero,
                  leading: const Icon(Icons.schedule),
                  title: const Text('Administered at'),
                  subtitle: Text(formatDateTime(_administeredAt)),
                  trailing: const Icon(Icons.edit_calendar_outlined),
                  onTap: _isSaving ? null : _pickAdministeredAt,
                ),
                const SizedBox(height: 8),
                Text(
                  'Injection site',
                  style: Theme.of(context).textTheme.titleSmall,
                ),
                const SizedBox(height: 4),
                for (final region in InjectionBodyRegion.values) ...[
                  Padding(
                    padding: const EdgeInsets.only(top: 8, bottom: 4),
                    child: Text(
                      region.displayName,
                      style: Theme.of(context)
                          .textTheme
                          .labelLarge
                          ?.copyWith(color: Colors.grey),
                    ),
                  ),
                  Wrap(
                    spacing: 8,
                    runSpacing: 4,
                    children: [
                      for (final site in InjectionSite.values
                          .where((site) => site.region == region))
                        ChoiceChip(
                          label: Text(site.shortLabel),
                          selected: _site == site,
                          onSelected: _isSaving
                              ? null
                              : (_) => setState(() => _site = site),
                        ),
                    ],
                  ),
                ],
              ],
            ),
          ),
        ),
      ),
      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.check_circle_outline),
          label: const Text('Log Injection'),
        ),
      ],
    );
  }

  /// Lets the user backdate the injection via sequential date/time pickers.
  Future<void> _pickAdministeredAt() async {
    final now = DateTime.now();
    final pickedDate = await showDatePicker(
      context: context,
      initialDate: _administeredAt,
      firstDate: DateTime(now.year - 1),
      lastDate: now,
    );
    if (pickedDate == null || !mounted) return;

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

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

  Future<void> _save() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;
    final doseMg = double.parse(_doseController.text.trim());

    setState(() => _isSaving = true);
    final saved =
        await ref.read(medicationControllerProvider.notifier).logInjection(
              compoundName: _compound.displayName,
              doseMg: doseMg,
              site: _site,
              administeredAt: _administeredAt,
            );
    if (!mounted) return;
    Navigator.of(context).pop(saved);
  }

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