main.dart

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

void main() {
  runApp(const ZakatCalculatorApp());
}

class ZakatCalculatorApp extends StatelessWidget {
  const ZakatCalculatorApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Zakat Qualification',
      theme: ThemeData(
        primarySwatch: Colors.teal,
        brightness: Brightness.light,
        scaffoldBackgroundColor: Colors.grey[50],
        appBarTheme: const AppBarTheme(
          elevation: 1,
          backgroundColor: Colors.white,
          foregroundColor: Colors.black,
        ),
        inputDecorationTheme: InputDecorationTheme(
          border: OutlineInputBorder(
            borderRadius: BorderRadius.circular(8.0),
          ),
          filled: true,
          fillColor: Colors.white,
        ),
        cardTheme: CardThemeData( // Changed CardTheme to CardThemeData
          elevation: 2,
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
        ),
      ),
      home: const ZakatQualificationScreen(),
      debugShowCheckedModeBanner: false,
    );
  }
}

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

  @override
  State<ZakatQualificationScreen> createState() => _ZakatQualificationScreenState();
}

class _ZakatQualificationScreenState extends State<ZakatQualificationScreen> {
  // --- State Variables ---
  int _currentStep = 0; // Controls which step of the wizard is shown
  String _disqualificationMessage = '';

  // Variables for the final calculation step
  final _goldAmountController = TextEditingController();
  bool _isPersonalJewelry = false;
  bool _isForInvestment = false;
  String _zakatResult = '';

  // --- Logic Functions ---

  /// Moves to the next step in the qualification wizard
  void _nextStep() {
    setState(() {
      _currentStep++;
    });
  }

  /// Handles when a user does not qualify for Zakat
  void _disqualify(String message) {
    setState(() {
      _disqualificationMessage = message;
      _currentStep = 100; // An arbitrary step number for the disqualification screen
    });
  }

  /// Resets the entire wizard to the beginning
  void _startOver() {
    setState(() {
      _currentStep = 0;
      _disqualificationMessage = '';
      _zakatResult = '';
      _goldAmountController.clear();
      _isPersonalJewelry = false;
      _isForInvestment = false;
    });
  }

  /// The final calculation logic
  void _calculateZakat() {
    const double nisabGold = 85.0; // ~20 Mithqal
    const double zakatRate = 0.025; // 2.5%

    final double? userAmount = double.tryParse(_goldAmountController.text);

    if (userAmount == null || userAmount <= 0) {
      setState(() {
        _zakatResult = 'Please enter a valid amount of gold in grams.';
      });
      return;
    }

    // Jewelry exception check
    if (_isPersonalJewelry && !_isForInvestment) {
      setState(() {
        _zakatResult = 'No Zakat is due on permissible jewelry intended for personal use.';
      });
      return;
    }

    // Nisab check
    if (userAmount < nisabGold) {
      setState(() {
        _zakatResult = 'No Zakat is due as your holding of ${userAmount.toStringAsFixed(2)}g is below the Nisab of 85g.';
      });
      return;
    }

    // Final Calculation
    final double zakatDue = userAmount * zakatRate;
    setState(() {
      _zakatResult = '''
Zakat is Obligatory.

Your Gold Holdings: ${userAmount.toStringAsFixed(2)}g
Nisab (Threshold): ${nisabGold.toStringAsFixed(2)}g

Zakat to be Paid: ${zakatDue.toStringAsFixed(3)}g of gold.
(or its equivalent cash value)
''';
    });
  }
  
  // --- UI Building Functions ---

  /// Builds a standard UI for a qualification question
  Widget _buildQualificationStep({
    required String question,
    required String info,
    required String disqualificationMessage,
  }) {
    return Center(
      child: Card(
        margin: const EdgeInsets.all(16.0),
        child: Padding(
          padding: const EdgeInsets.all(24.0),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Text(
                question,
                textAlign: TextAlign.center,
                style: const TextStyle(fontSize: 20, fontWeight: FontWeight.w600),
              ),
              const SizedBox(height: 8),
              Text(info, textAlign: TextAlign.center, style: TextStyle(color: Colors.grey[600])),
              const SizedBox(height: 24),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: [
                  ElevatedButton(
                    onPressed: () => _disqualify(disqualificationMessage),
                    style: ElevatedButton.styleFrom(backgroundColor: Colors.red[700]),
                    child: const Text('No'),
                  ),
                  ElevatedButton(
                    onPressed: _nextStep,
                    child: const Text('Yes'),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// Builds the UI for the final step: entering the amount and calculating
  Widget _buildCalculatorStep() {
     return SingleChildScrollView(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            children: [
                Text("Congratulations, you've met the initial conditions for Zakat!", textAlign: TextAlign.center, style: TextStyle(color: Colors.green[800], fontWeight: FontWeight.bold)),
                const SizedBox(height: 16),
                Card(
                  child: Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        const Text('Enter Gold Amount', style: TextStyle(fontWeight: FontWeight.bold, fontSize: 16)),
                        const SizedBox(height: 16),
                        TextFormField(
                          controller: _goldAmountController,
                          keyboardType: const TextInputType.numberWithOptions(decimal: true),
                          decoration: const InputDecoration(labelText: 'Amount in grams (جرام)', prefixIcon: Icon(Icons.balance)),
                        ),
                      ],
                    ),
                  ),
                ),
                const SizedBox(height: 16),
                Card(
                    child: Column(children: [
                      SwitchListTile(
                        title: const Text('Is this for personal use as jewelry?'),
                        value: _isPersonalJewelry,
                        onChanged: (bool value) {
                          setState(() {
                            _isPersonalJewelry = value;
                            if (!value) _isForInvestment = false;
                          });
                        },
                      ),
                      if (_isPersonalJewelry)
                        SwitchListTile(
                          title: const Text('Do you intend to save it as an asset?'),
                          value: _isForInvestment,
                          onChanged: (bool value) => setState(() => _isForInvestment = value),
                        ),
                    ]),
                ),
              const SizedBox(height: 24),
              ElevatedButton(
                onPressed: _calculateZakat,
                style: ElevatedButton.styleFrom(padding: const EdgeInsets.symmetric(vertical: 16), textStyle: const TextStyle(fontSize: 18, fontWeight: FontWeight.bold)),
                child: const Text('Calculate Zakat (احسب الزكاة)'),
              ),
              const SizedBox(height: 24),
              if (_zakatResult.isNotEmpty)
                Card(
                  color: Theme.of(context).primaryColor.withOpacity(0.1),
                  child: Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: Text(_zakatResult, textAlign: TextAlign.center, style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w500, height: 1.5)),
                  ),
                ),
             if (_zakatResult.isNotEmpty) ...[const SizedBox(height: 20), TextButton(onPressed: _startOver, child: const Text("Start Over"))]
            ],
          ),
        ),
      );
  }
  
  /// Builds the UI for a user who is disqualified
  Widget _buildDisqualificationScreen() {
      return Center(
        child: Card(
          color: Colors.red[50],
          margin: const EdgeInsets.all(16.0),
          child: Padding(
            padding: const EdgeInsets.all(24.0),
            child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                    Text("Zakat Not Obligatory", style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold, color: Colors.red[800])),
                    const SizedBox(height: 16),
                    Text(_disqualificationMessage, textAlign: TextAlign.center, style: const TextStyle(fontSize: 16)),
                    const SizedBox(height: 24),
                    ElevatedButton(onPressed: _startOver, child: const Text("Start Over"))
                ],
            ),
          ),
        ),
      );
  }
  
  /// The main build method that routes to the correct step
  @override
  Widget build(BuildContext context) {
    Widget currentWidget;

    switch (_currentStep) {
      case 0: // Welcome Screen
        currentWidget = Center(child: ElevatedButton(onPressed: _nextStep, style: ElevatedButton.styleFrom(padding: const EdgeInsets.symmetric(horizontal: 40, vertical: 20)), child: const Text("Start Zakat Qualification", style: TextStyle(fontSize: 16))));
        break;
      case 1:
        currentWidget = _buildQualificationStep(question: "Are you a Muslim?", info: "Zakat is a primary obligation for Muslims.", disqualificationMessage: "Zakat, as a pillar of Islam, is obligatory upon Muslims.");
        break;
      case 2:
        currentWidget = _buildQualificationStep(question: "Are you a free person?", info: "The obligation is specified for a free person.", disqualificationMessage: "The specific conditions of Zakat discussed here apply to free individuals.");
        break;
      case 3:
        currentWidget = _buildQualificationStep(question: "Is this wealth your personal property?", info: "i.e., not part of a public trust or general waqf.", disqualificationMessage: "Zakat on a principal amount is not required for wealth held in a general trust (e.g., for a mosque).");
        break;
      case 4:
         currentWidget = _buildQualificationStep(question: "Has a full Hijri (lunar) year passed on this wealth?", info: "This is a required condition for Zakat on currency and trade goods.", disqualificationMessage: "A full lunar year must pass over the wealth (while it is above Nisab) for Zakat to be due.");
        break;
      case 5: // The final calculator
        currentWidget = _buildCalculatorStep();
        break;
      default: // Disqualification screen
        currentWidget = _buildDisqualificationScreen();
    }

    return Scaffold(
      appBar: AppBar(title: const Text('Zakat Qualification')),
      body: AnimatedSwitcher(
          duration: const Duration(milliseconds: 300),
          child: currentWidget,
      )
    );
  }

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