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

import 'package:cipher_guard_sdk/cipher_guard_sdk.dart';

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

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

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _platformVersion = 'Unknown';
  final CipherGuardSdkApi _sdk = CipherGuardSdkApi();
  
  // 加密相關狀態
  RsaKeyPair? _keyPair;
  String? _encryptedPrivateKey;
  SessionKey? _sessionKey;
  EncryptedMessage? _encryptedMessage;
  String _decryptedMessage = '';
  String _statusMessage = '';

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

  Future<void> initPlatformState() async {
    String platformVersion;
    try {
      platformVersion = (await _sdk.platformVersion()) ?? 'Unknown platform version';
    } catch (e) {
      platformVersion = 'Failed to get platform version: $e';
    }

    if (!mounted) return;

    setState(() {
      _platformVersion = platformVersion;
    });
  }

  // ==================== RSA 金鑰管理 ====================
  
  Future<void> _generateRsaKeyPair() async
  {
    setState(() => _statusMessage = 'Generating RSA key pair...');
    try {
      final keyPair = await _sdk.generateRsaKeyPair(keySize: 1024);
      setState(() {
        _keyPair = keyPair;
        _statusMessage = 'RSA key pair generated successfully!\nPublic Key: ${keyPair.publicKey.substring(0, 50)}...';
      });
    } catch (e) {
      print("_generateRsaKeyPair error: $e");
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  Future<void> _encryptPrivateKey() async
  {
    if (_keyPair == null) {
      setState(() => _statusMessage = 'Please generate RSA key pair first!');
      return;
    }
    
    const password = 'user_password_123';
    setState(() => _statusMessage = 'Encrypting private key with password...');
    try {
      final encrypted = await _sdk.encryptPrivateKey(
        privateKey: _keyPair!.privateKey,
        password: password,
      );
      setState(() {
        _encryptedPrivateKey = encrypted;
        _statusMessage = 'Private key encrypted successfully!';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  Future<void> _decryptPrivateKey() async
  {
    if (_encryptedPrivateKey == null) {
      setState(() => _statusMessage = 'No encrypted private key to decrypt!');
      return;
    }
    
    const password = 'user_password_123';
    setState(() => _statusMessage = 'Decrypting private key...');
    try {
      final decrypted = await _sdk.decryptPrivateKey(
        encryptedPrivateKey: _encryptedPrivateKey!,
        password: password,
      );
      setState(() {
        _statusMessage = 'Private key decrypted successfully!\n$decrypted';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  // ==================== 會話金鑰管理 ====================
  
  Future<void> _generateSessionKey() async
  {
    setState(() => _statusMessage = 'Generating session key...');
    try {
      final sessionKey = await _sdk.generateSessionKey(initialRound: 1);
      setState(() {
        _sessionKey = sessionKey;
        _statusMessage = 'Session key generated!\nKey: ${sessionKey.key}\nRound: ${sessionKey.round}';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  Future<void> _encryptSessionKey() async
  {
    if (_sessionKey == null || _keyPair == null) {
      setState(() => _statusMessage = 'Please generate session key and RSA key pair first!');
      return;
    }
    
    setState(() => _statusMessage = 'Encrypting session key with RSA public key...');

    try {
      final encrypted = await _sdk.encryptSessionKey(
        sessionKey: _sessionKey!.key,
        publicKey: _keyPair!.publicKey,
      );
      setState(() {
        _statusMessage = 'Session key encrypted successfully!\n$encrypted';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  Future<void> _decryptSessionKey() async
  {
    if (_keyPair == null) {
      setState(() => _statusMessage = 'Please generate RSA key pair first!');
      return;
    }
    
    // 這裡應該使用之前加密的會話金鑰
    if (_sessionKey == null) {
      setState(() => _statusMessage = 'Please generate session key first!');
      return;
    }
    
    setState(() => _statusMessage = 'Decrypting session key...');
    try {
      // 先加密再解密測試
      final encrypted = await _sdk.encryptSessionKey(
        sessionKey: _sessionKey!.key,
        publicKey: _keyPair!.publicKey,
      );
      final decrypted = await _sdk.decryptSessionKey(
        encryptedSessionKey: encrypted,
        privateKey: _keyPair!.privateKey,
      );
      setState(() {
        _statusMessage = 'Session key decrypted successfully!\nOriginal: ${_sessionKey!.key}\nDecrypted: $decrypted';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  // ==================== 訊息加解密 ====================
  
  Future<void> _encryptMessage() async
  {
    if (_sessionKey == null) {
      setState(() => _statusMessage = 'Please generate session key first!');
      return;
    }
    
    const plaintext = 'Hello, this is a secret message!';
    setState(() => _statusMessage = 'Encrypting message...');
    try {
      final encrypted = await _sdk.encryptMessage(
        plaintext: plaintext,
        sessionKey: _sessionKey!.key,
        round: _sessionKey!.round,
      );
      setState(() {
        _encryptedMessage = encrypted;
        _statusMessage = 'Message encrypted!\nRound: ${encrypted.round}\nData: ${encrypted.data}';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  Future<void> _decryptMessage() async
  {
    if (_encryptedMessage == null || _sessionKey == null) {
      setState(() => _statusMessage = 'No encrypted message to decrypt!');
      return;
    }
    
    setState(() => _statusMessage = 'Decrypting message...');
    try {
      final decrypted = await _sdk.decryptMessage(
        encryptedData: _encryptedMessage!.data,
        sessionKey: _sessionKey!.key,
        round: _encryptedMessage!.round,
      );
      setState(() {
        _decryptedMessage = decrypted;
        _statusMessage = 'Message decrypted: $decrypted';
      });
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  // ==================== 原生平台同步 ====================
  
  Future<void> _syncEncryptionKeys() async
  {
    if (_sessionKey == null) {
      setState(() => _statusMessage = 'Please generate session key first!');
      return;
    }
    
    setState(() => _statusMessage = 'Syncing encryption keys to native...');
    try {
      await _sdk.syncEncryptionKey(
        chatId: 'test_chat_123',
        activeRound: _sessionKey!.round,
        round: _sessionKey!.round,
        activeKey: _sessionKey!.key,
        isSingle: false,
      );
      setState(() => _statusMessage = 'Encryption keys synced to native platform!');
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  // ==================== 推送通知解密 ====================
  
  Future<void> _setupAesSecret() async
  {
    // 設置 release.json 中的 AES_SECRET
    const aesSecret = '468171c825c02408cc99935447c785a5';
    setState(() => _statusMessage = 'Setting AES_SECRET...');
    try {
      await _sdk.setAesSecret(aesSecret: aesSecret);
      setState(() => _statusMessage = 'AES_SECRET set successfully!');
    } catch (e) {
      setState(() => _statusMessage = 'Error: $e');
    }
  }

  @override
  Widget build(BuildContext context)
  {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('CipherGuard SDK Example'),
        ),
        body: SingleChildScrollView(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text('Running on: $_platformVersion\n', style: Theme.of(context).textTheme.titleMedium),
              
              const Text('=== RSA 金鑰管理 ===', style: TextStyle(fontWeight: FontWeight.bold)),

              Row(
                children: [
                  Expanded(
                    child:ElevatedButton(onPressed: _generateRsaKeyPair, child: const Text('生成 RSA 金鑰對',)
                    ),
                  ),
                  const SizedBox(width: 8),
                  Expanded(child: ElevatedButton(onPressed: _keyPair != null ? _encryptPrivateKey : null, child: const Text('加密私鑰',style: TextStyle(fontSize: 10),))),
                  const SizedBox(width: 8),
                  Expanded(child: ElevatedButton(onPressed: _encryptedPrivateKey != null ? _decryptPrivateKey : null, child: const Text('解密私鑰',style: TextStyle(fontSize: 10),)),),
                ],
              ),

              const SizedBox(height: 8),
              
              const Text('=== 會話金鑰管理 ===', style: TextStyle(fontWeight: FontWeight.bold)),

              Row(
                children: [
                  Expanded(
                    child: ElevatedButton(onPressed: _generateSessionKey, child: const Text('生成會話金鑰',style: TextStyle(fontSize: 10),)),
                  ),

                  const SizedBox(width: 8),

                  Expanded(
                    child: ElevatedButton(
                        onPressed: (_sessionKey != null && _keyPair != null) ? _encryptSessionKey : null,
                        child: const Text('加密會話金鑰',style: TextStyle(fontSize: 10),)
                    ),
                  ),
                  const SizedBox(width: 8),
                  Expanded(
                    child: ElevatedButton(
                        onPressed: (_keyPair != null && _sessionKey != null) ? _decryptSessionKey : null,
                        child: const Text('解密會話金鑰',style: TextStyle(fontSize: 10),)
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 8),
              
              const Text('=== 訊息加解密 ===', style: TextStyle(fontWeight: FontWeight.bold)),
              Row(
                children: [
                  ElevatedButton(
                    onPressed: _sessionKey != null ? _encryptMessage : null, 
                    child: const Text('加密訊息')
                  ),
                  const SizedBox(width: 8),
                  ElevatedButton(
                    onPressed: _encryptedMessage != null ? _decryptMessage : null, 
                    child: const Text('解密訊息')
                  ),
                ],
              ),
              if (_decryptedMessage.isNotEmpty)
                Text('解密結果: $_decryptedMessage', style: const TextStyle(color: Colors.green)),
              const SizedBox(height: 8),
              
              const Text('=== 原生平台同步 ===', style: TextStyle(fontWeight: FontWeight.bold)),
              ElevatedButton(
                onPressed: _sessionKey != null ? _syncEncryptionKeys : null, 
                child: const Text('同步加密金鑰到原生')
              ),
              const SizedBox(height: 8),
              
              const Text('=== 推送通知解密 ===', style: TextStyle(fontWeight: FontWeight.bold)),
              ElevatedButton(onPressed: _setupAesSecret, child: const Text('設置 AES_SECRET')),
              const SizedBox(height: 16),
              
              Container(
                padding: const EdgeInsets.all(12),
                color: Colors.grey[200],
                width: double.infinity,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text('狀態:', style: TextStyle(fontWeight: FontWeight.bold)),
                    Text(_statusMessage),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}