import 'package:flutter/material.dart';
import 'package:uto_manager/domain/entities/authorized_rank.dart';
import 'package:uto_manager/domain/entities/position_slot.dart';
import 'package:uto_manager/domain/value_objects/duty_mos.dart';
import 'package:uuid/uuid.dart';

/// Dialog for creating or editing a [PositionSlot] within a unit.
///
/// Pass [existing] to edit; leave null to create a new slot.
/// [unitId] is required and identifies which unit owns this slot.
class AddEditSlotDialog extends StatefulWidget {
  const AddEditSlotDialog({
    required this.unitId,
    super.key,
    this.existing,
  });

  final String unitId;
  final PositionSlot? existing;

  @override
  State<AddEditSlotDialog> createState() => _AddEditSlotDialogState();
}

class _AddEditSlotDialogState extends State<AddEditSlotDialog> {
  final _formKey = GlobalKey<FormState>();
  late final TextEditingController _titleCtrl;
  late final TextEditingController _mosCtrl;

  late AuthorizedRank _rank;
  late bool _isKeyLeader;
  List<String> _mosSuggestions = [];

  bool get _isEditing => widget.existing != null;

  @override
  void initState() {
    super.initState();
    final e = widget.existing;
    _titleCtrl = TextEditingController(text: e?.positionTitle ?? '');
    _mosCtrl = TextEditingController(text: e?.dutyMos.code ?? '');
    _rank = e?.authorizedRank ?? AuthorizedRank.e4;
    _isKeyLeader = e?.isKeyLeader ?? false;
  }

  @override
  void dispose() {
    _titleCtrl.dispose();
    _mosCtrl.dispose();
    super.dispose();
  }

  void _updateMosSuggestions(String query) {
    if (query.isEmpty) {
      setState(() => _mosSuggestions = []);
      return;
    }
    final q = query.toUpperCase();
    final matches =
        DutyMos.allCodes.where((c) => c.startsWith(q) || c.contains(q)).take(12).toList()..sort();
    setState(() => _mosSuggestions = matches);
  }

  void _submit() {
    if (!_formKey.currentState!.validate()) return;

    final mosCode = _mosCtrl.text.trim().toUpperCase();
    DutyMos mos;
    try {
      mos = DutyMos(mosCode);
    } catch (_) {
      mos = DutyMos.unvalidated(mosCode);
    }

    final slot = PositionSlot(
      slotId: widget.existing?.slotId ?? const Uuid().v4(),
      unitId: widget.unitId,
      positionTitle: _titleCtrl.text.trim(),
      dutyMos: mos,
      authorizedRank: _rank,
      isKeyLeader: _isKeyLeader,
      assignedPersonnelId: widget.existing?.assignedPersonnelId,
    );

    Navigator.of(context).pop(slot);
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return AlertDialog(
      title: Row(
        children: [
          Icon(_isEditing ? Icons.edit : Icons.add_circle_outline, size: 20),
          const SizedBox(width: 8),
          Text(_isEditing ? 'Edit Position Slot' : 'Add Position Slot'),
        ],
      ),
      content: SizedBox(
        width: 400,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                // Position Title
                TextFormField(
                  controller: _titleCtrl,
                  decoration: const InputDecoration(
                    labelText: 'Position Title',
                    hintText: 'e.g. Platoon Leader, Squad Leader, Medic',
                    prefixIcon: Icon(Icons.work_history_outlined),
                  ),
                  textCapitalization: TextCapitalization.words,
                  validator: (v) {
                    if (v == null || v.trim().isEmpty) return 'Position title is required';
                    return null;
                  },
                ),
                const SizedBox(height: 12),

                // Authorized Rank
                DropdownButtonFormField<AuthorizedRank>(
                  initialValue: _rank,
                  decoration: const InputDecoration(
                    labelText: 'Authorized Rank',
                    prefixIcon: Icon(Icons.military_tech_outlined),
                  ),
                  items: AuthorizedRank.values.map((r) {
                    return DropdownMenuItem(
                      value: r,
                      child: Text('${r.payGrade} — ${r.rankTitle}'),
                    );
                  }).toList(),
                  onChanged: (v) => setState(() => _rank = v!),
                ),
                const SizedBox(height: 12),

                // Duty MOS with autocomplete
                TextFormField(
                  controller: _mosCtrl,
                  decoration: const InputDecoration(
                    labelText: 'Duty MOS',
                    hintText: 'e.g. 11B, 68W, 25U',
                    prefixIcon: Icon(Icons.badge_outlined),
                  ),
                  textCapitalization: TextCapitalization.characters,
                  onChanged: _updateMosSuggestions,
                  validator: (v) {
                    if (v == null || v.trim().isEmpty) return 'Duty MOS is required';
                    final code = v.trim().toUpperCase();
                    if (!DutyMos.isKnown(code)) {
                      return 'Unknown MOS code (e.g. 11B, 68W, 25U)';
                    }
                    return null;
                  },
                ),
                if (_mosSuggestions.isNotEmpty) ...[
                  const SizedBox(height: 4),
                  Container(
                    padding: const EdgeInsets.all(4),
                    decoration: BoxDecoration(
                      color: theme.colorScheme.surfaceContainerHigh,
                      borderRadius: BorderRadius.circular(6),
                      border: Border.all(color: theme.colorScheme.outlineVariant),
                    ),
                    child: Wrap(
                      spacing: 4,
                      runSpacing: 4,
                      children: _mosSuggestions.map((code) {
                        return ActionChip(
                          label: Text(
                            code,
                            style: theme.textTheme.labelSmall?.copyWith(
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          onPressed: () {
                            _mosCtrl.text = code;
                            setState(() => _mosSuggestions = []);
                          },
                          padding: const EdgeInsets.symmetric(horizontal: 4),
                          visualDensity: VisualDensity.compact,
                        );
                      }).toList(),
                    ),
                  ),
                ],
                const SizedBox(height: 8),

                // Key Leader toggle
                SwitchListTile(
                  title: const Text('Key Leader Position'),
                  subtitle: const Text('e.g. Commander, XO, Platoon Leader, PSG'),
                  value: _isKeyLeader,
                  onChanged: (v) => setState(() => _isKeyLeader = v),
                  contentPadding: EdgeInsets.zero,
                  dense: true,
                ),
              ],
            ),
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          icon: Icon(_isEditing ? Icons.save : Icons.add, size: 16),
          label: Text(_isEditing ? 'Save Changes' : 'Add Slot'),
          onPressed: _submit,
        ),
      ],
    );
  }
}