import 'dart:async';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../../providers/installer_mode_provider.dart';
import '../../theme/app_theme.dart';
import '../../theme/etm_theme.dart';

/// Dialog de saisie du PIN installateur.
/// Affiche un clavier numérique avec indicateurs de saisie,
/// gestion des tentatives échouées et countdown en cas de verrouillage.
class InstallerPinDialog extends StatefulWidget {
  const InstallerPinDialog({super.key});

  @override
  State<InstallerPinDialog> createState() => _InstallerPinDialogState();
}

class _InstallerPinDialogState extends State<InstallerPinDialog> {
  String _pin        = '';
  String? _error;
  bool   _checking   = false;
  Timer? _countdownTimer;
  int    _countdown  = 0;

  @override
  void dispose() {
    _countdownTimer?.cancel();
    super.dispose();
  }

  void _append(String digit) {
    if (_checking || _pin.length >= 6) return;
    setState(() {
      _pin  = _pin + digit;
      _error = null;
    });
    if (_pin.length >= 4) {
      _tryUnlock();
    }
  }

  void _delete() {
    if (_pin.isEmpty) return;
    setState(() => _pin = _pin.substring(0, _pin.length - 1));
  }

  Future<void> _tryUnlock() async {
    final provider = context.read<InstallerModeProvider>();
    if (provider.isLocked) {
      _startCountdown(provider.lockRemaining.inSeconds);
      return;
    }

    setState(() => _checking = true);
    final result = await provider.unlock(_pin);
    if (!mounted) return;

    switch (result) {
      case UnlockResult.success:
        Navigator.of(context).pop(true);
        break;
      case UnlockResult.wrongPin:
        setState(() {
          _checking = false;
          _pin      = '';
          _error    = provider.isLocked
              ? 'PIN incorrect. Veuillez patienter.'
              : 'PIN incorrect (${provider.failedAttempts} tentative${provider.failedAttempts > 1 ? 's' : ''} restante${(3 - provider.failedAttempts) > 1 ? 's' : ''})';
        });
        if (provider.isLocked) {
          _startCountdown(provider.lockRemaining.inSeconds);
        }
        break;
      case UnlockResult.locked:
        setState(() {
          _checking = false;
          _pin      = '';
        });
        _startCountdown(provider.lockRemaining.inSeconds);
        break;
    }
  }

  void _startCountdown(int seconds) {
    _countdown = seconds;
    _countdownTimer?.cancel();
    _countdownTimer = Timer.periodic(const Duration(seconds: 1), (t) {
      if (!mounted) { t.cancel(); return; }
      setState(() {
        _countdown--;
        if (_countdown <= 0) {
          t.cancel();
          _error = null;
        } else {
          _error = 'Trop de tentatives. Réessayez dans $_countdown s';
        }
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Dialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
      child: Padding(
        padding: const EdgeInsets.fromLTRB(24, 28, 24, 24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            // ── Icône ────────────────────────────────────────────────────────
            Container(
              width: 52, height: 52,
              decoration: BoxDecoration(
                color: ETMTheme.installerBadgeColor.withValues(alpha: 0.12),
                shape: BoxShape.circle,
              ),
              child: const Icon(
                Icons.build_rounded,
                color: ETMTheme.installerBadgeColor,
                size: 26,
              ),
            ),
            const SizedBox(height: 14),
            const Text(
              'Mode Installateur',
              style: TextStyle(fontSize: 17, fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 4),
            const Text(
              'Entrez votre PIN pour continuer',
              style: TextStyle(fontSize: 13, color: Color(0xFF6B7280)),
            ),
            const SizedBox(height: 20),

            // ── Indicateurs PIN ──────────────────────────────────────────────
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: List.generate(6, (i) {
                final filled = i < _pin.length;
                return Container(
                  width: 14, height: 14,
                  margin: const EdgeInsets.symmetric(horizontal: 5),
                  decoration: BoxDecoration(
                    shape: BoxShape.circle,
                    color: filled
                        ? ETMTheme.installerBadgeColor
                        : Colors.grey.shade200,
                    border: Border.all(
                      color: filled
                          ? ETMTheme.installerBadgeColor
                          : Colors.grey.shade400,
                    ),
                  ),
                );
              }),
            ),

            if (_checking) ...[
              const SizedBox(height: 16),
              const SizedBox(
                width: 24, height: 24,
                child: CircularProgressIndicator(
                  strokeWidth: 2.5,
                  color: ETMTheme.installerBadgeColor,
                ),
              ),
            ] else if (_error != null) ...[
              const SizedBox(height: 10),
              Text(
                _error!,
                textAlign: TextAlign.center,
                style: TextStyle(
                  fontSize: 12,
                  color: ETMTheme.errorColor,
                ),
              ),
            ],

            const SizedBox(height: 20),

            // ── Clavier numérique ────────────────────────────────────────────
            ...[
              ['1', '2', '3'],
              ['4', '5', '6'],
              ['7', '8', '9'],
              ['', '0', '⌫'],
            ].map((row) => Padding(
                  padding: const EdgeInsets.only(bottom: 8),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: row.map((k) {
                      if (k.isEmpty) {
                        return const SizedBox(width: 70, height: 52);
                      }
                      return _KeyButton(
                        label: k,
                        onTap: () {
                          if (k == '⌫') {
                            _delete();
                          } else {
                            _append(k);
                          }
                        },
                        isDelete: k == '⌫',
                        disabled: _checking || _countdown > 0,
                      );
                    }).toList(),
                  ),
                )),

            // ── Bouton Annuler ───────────────────────────────────────────────
            TextButton(
              onPressed: () => Navigator.of(context).pop(false),
              child: const Text('Annuler'),
            ),
          ],
        ),
      ),
    );
  }
}

class _KeyButton extends StatelessWidget {
  final String   label;
  final VoidCallback onTap;
  final bool     isDelete;
  final bool     disabled;

  const _KeyButton({
    required this.label,
    required this.onTap,
    this.isDelete = false,
    this.disabled = false,
  });

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: disabled ? null : onTap,
      child: Container(
        width: 70, height: 52,
        margin: const EdgeInsets.symmetric(horizontal: 6),
        decoration: BoxDecoration(
          color: isDelete
              ? Colors.grey.shade100
              : Colors.grey.shade50,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: Colors.grey.shade200),
        ),
        child: Center(
          child: Text(
            label,
            style: TextStyle(
              fontSize: isDelete ? 18 : 22,
              fontWeight: FontWeight.w500,
              color: disabled
                  ? Colors.grey.shade400
                  : AppTheme.textDark,
            ),
          ),
        ),
      ),
    );
  }
}