import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:qpay/models/responsive_policy.dart';
import 'package:qpay/screens/onboarding/verify/verify_controller.dart';
import 'package:skeletonizer/skeletonizer.dart';

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

  @override
  State<VerifyScreen> createState() => _VerifyScreenState();
}

class _VerifyScreenState extends State<VerifyScreen> {
  late VerifyController verifyController;
  String? errorMessage;

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

    verifyController = VerifyController(context);
  }

  final List<TextEditingController> _codeControllers = List.generate(
    6,
    (index) => TextEditingController(),
  );
  final List<FocusNode> _focusNodes = List.generate(6, (index) => FocusNode());

  @override
  void dispose() {
    for (var controller in _codeControllers) {
      controller.dispose();
    }
    for (var node in _focusNodes) {
      node.dispose();
    }
    super.dispose();
  }

  void showErrorMessage(String? message) {
    setState(() {
      errorMessage = message;
    });
  }

  void _onCodeChanged(String value, int index) {
    if (value.length == 1 && index < 5) {
      _focusNodes[index + 1].requestFocus();
    }
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: verifyController,
      builder: (context, child) {
        return Scaffold(
          body: SingleChildScrollView(
            child: Padding(
              padding: const EdgeInsets.all(25),
              child: Center(
                child: LayoutBuilder(
                    builder: (context, constraints) {
                      final maxWidth = constraints.maxWidth > ResponsivePolicy.md
                          ? ResponsivePolicy.md.toDouble()
                          : constraints.maxWidth;
                      return SizedBox(
                        width: maxWidth,
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: [
                          SizedBox(height: 75),
                          Text(
                            'Verify Your Account',
                            style: TextStyle(
                              fontSize: 30,
                              fontWeight: FontWeight.bold,
                              color: Theme.of(context).colorScheme.primary,
                            ),
                          ),
                          SizedBox(height: 5),
                          Text(
                            'Enter the 6-digit code sent to your phone/email',
                            style: TextStyle(fontSize: 18),
                            textAlign: TextAlign.center,
                          ),
                          Image.asset('assets/verify.png', width: 300),
                          // Verification Code Input
                          Row(
                            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                            children: List.generate(
                              6,
                              (index) => SizedBox(
                                width: 50,
                                child: TextFormField(
                                  controller: _codeControllers[index],
                                  focusNode: _focusNodes[index],
                                  textAlign: TextAlign.center,
                                  keyboardType: TextInputType.number,
                                  maxLength: 1,
                                  decoration: InputDecoration(
                                    counterText: '',
                                    border: OutlineInputBorder(
                                      borderRadius: BorderRadius.circular(12),
                                      borderSide: BorderSide(color: Colors.grey.shade300),
                                    ),
                                    focusedBorder: OutlineInputBorder(
                                      borderRadius: BorderRadius.circular(12),
                                      borderSide: BorderSide(
                                        color: Theme.of(context).colorScheme.primary,
                                        width: 2,
                                      ),
                                    ),
                                    contentPadding: EdgeInsets.symmetric(vertical: 16),
                                  ),
                                  onChanged: (value) => _onCodeChanged(value, index),
                                ),
                              ),
                            ),
                          ),
                          SizedBox(height: 5),
                          if(errorMessage != null)
                            Text(errorMessage ?? '', style: TextStyle(color: Colors.red)),
                          SizedBox(height: 30),
                          // Resend Code Section
                          Row(
                            mainAxisAlignment: MainAxisAlignment.center,
                            children: [
                              Text(
                                "Didn't receive the code? ",
                                style: TextStyle(color: Colors.grey.shade600, fontSize: 16),
                              ),
                              TextButton(
                                onPressed: () {
                                  verifyController.resendOtp();
                                },
                                child: Text(
                                  'Resend Code',
                                  style: TextStyle(
                                    color: Theme.of(context).colorScheme.primary,
                                    fontSize: 16,
                                    fontWeight: FontWeight.w600,
                                  ),
                                ),
                              ),
                            ],
                          ),
                          // SizedBox(height: 20),
                          // // Timer for resend (optional)
                          // Text(
                          //   'Resend available in 2:30',
                          //   style: TextStyle(color: Colors.grey.shade500, fontSize: 14),
                          // ),
                          SizedBox(height: 40),
                          Padding(
                            padding: const EdgeInsets.symmetric(horizontal: 25),
                            child: Skeletonizer(
                              enabled: verifyController.model.isLoading,
                              child: Row(
                                children: [
                                  Expanded(
                                    child: ElevatedButton(
                                      onPressed: () async {
                                        showErrorMessage(null);
                                        String code = '';
                                        for (var controller in _codeControllers) {
                                          code += controller.text;
                                        }

                                        if(code.length != 6) {
                                          showErrorMessage('Invalid code');
                                          return;
                                        }
                                        verifyController.updateCode(code);
                                        await verifyController.verifyOtp();
                                        if(verifyController.model.status == 'done') {
                                          context.go('/onboarding/complete');
                                        }
                                      },
                                      child: Text(
                                        'Verify Code',
                                        style: TextStyle(fontSize: 16),
                                      ),
                                    ),
                                  ),
                                  SizedBox(width: 16),
                                  Expanded(
                                    child: OutlinedButton(
                                      onPressed: () {
                                        context.go('/onboarding/login');
                                      },
                                      child: Text(
                                        'Back to Login',
                                        style: TextStyle(fontSize: 16),
                                      ),
                                    ),
                                  ),
                                ],
                              ),
                            ),
                          ),
                          SizedBox(height: 10),
                          TextButton(
                            onPressed: () {
                              context.go('/');
                            },
                            child: Text('Continue as guest?', style: TextStyle(fontSize: 14)),
                          ),

                        ],
                      ),
                    );
                  }
                ),
              ),
            ),
          ),
        );
      }
    );
  }
}