import 'package:flutter/material.dart';

import 'src/rtty_mobile_client.dart';
import 'src/theme.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Rtty Mobile',
      debugShowCheckedModeBanner: false,
      theme: RttyMobileTheme.app(),
      home: const TerminalPage(),
    );
  }
}

/// 最小验证页：连接 Rtty 服务端，消费语义化快照实时显示终端内容，
/// 并支持输入命令 + 常用按键（ESC/TAB/Ctrl/方向键）做端到端同步验证。
class TerminalPage extends StatefulWidget {
  const TerminalPage({super.key});

  @override
  State<TerminalPage> createState() => _TerminalPageState();
}

class _TerminalPageState extends State<TerminalPage> {
  final RttyMobileClient _client = RttyMobileClient();
  final TextEditingController _serverCtrl = TextEditingController();
  final TextEditingController _tokenCtrl = TextEditingController();
  final TextEditingController _sessionCtrl = TextEditingController();
  final TextEditingController _inputCtrl = TextEditingController();
  final ScrollController _scrollCtrl = ScrollController();

  ConnState _state = ConnState.disconnected;
  String? _sessionId;
  bool _resumed = false;
  List<String> _lines = const [];
  int _cursorX = 0;
  int _cursorY = 0;

  /// 终端行高（逻辑像素），与 [_buildLine] 的字号/行高保持一致，
  /// 用于“让光标行保持可见”的滚动计算。
  static const double _lineHeight = 17.0;

  /// 常用按键：标签 -> 发送到 PTY 的字节序列。
  static const List<(String, String)> _quickKeys = [
    ('ESC', '\x1b'),
    ('TAB', '\t'),
    ('CTRL+C', '\x03'),
    ('CTRL+L', '\x0c'),
    ('↑', '\x1b[A'),
    ('↓', '\x1b[B'),
    ('←', '\x1b[D'),
    ('→', '\x1b[C'),
  ];

  @override
  void initState() {
    super.initState();
    _client.onStateChanged = _onStateChanged;
    _client.onReady = (id, cols, rows, resumed) {
      if (!mounted) return;
      setState(() {
        _sessionId = id;
        _resumed = resumed;
        _state = ConnState.connected;
      });
    };
    _client.onSnapshot = _onSnapshot;
    _client.onSessionClosed = () {
      if (!mounted) return;
      setState(() => _state = ConnState.disconnected);
    };
  }

  @override
  void dispose() {
    _client.disconnect();
    _serverCtrl.dispose();
    _tokenCtrl.dispose();
    _sessionCtrl.dispose();
    _inputCtrl.dispose();
    _scrollCtrl.dispose();
    super.dispose();
  }

  void _onStateChanged(ConnState s) {
    if (!mounted) return;
    setState(() {
      _state = s;
      if (s == ConnState.disconnected || s == ConnState.error) {
        _sessionId = null;
        _resumed = false;
      }
    });
  }

  void _onSnapshot(Snapshot snap) {
    if (!mounted) return;
    setState(() {
      _lines = snap.lines;
      _cursorX = snap.cursorX;
      _cursorY = snap.cursorY;
    });
    // 终端语义：让光标行始终可见（尽量靠近视口底部），而不是盲目滚到
    // 列表末尾——网格下半部分通常是空行，滚到底会把内容顶出屏幕。
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (!_scrollCtrl.hasClients) return;
      final viewport = _scrollCtrl.position.viewportDimension;
      final max = _scrollCtrl.position.maxScrollExtent;
      final target = ((_cursorY + 1) * _lineHeight) - viewport;
      _scrollCtrl.jumpTo(target.clamp(0.0, max));
    });
  }

  (String, int) _parseServer() {
    final raw = _serverCtrl.text.trim();
    if (raw.isEmpty) return ('', 8080);
    final idx = raw.lastIndexOf(':');
    if (idx <= 0) return (raw, 8080);
    final port = int.tryParse(raw.substring(idx + 1)) ?? 8080;
    return (raw.substring(0, idx), port);
  }

  Future<void> _connect() async {
    final (host, port) = _parseServer();
    if (host.isEmpty) {
      _showSnack('请输入服务端地址，如 192.168.1.100:8080');
      return;
    }
    setState(() => _state = ConnState.connecting);
    await _client.connect(
      host: host,
      port: port,
      session:
          _sessionCtrl.text.trim().isEmpty ? null : _sessionCtrl.text.trim(),
      token: _tokenCtrl.text.trim().isEmpty ? null : _tokenCtrl.text.trim(),
    );
  }

  Future<void> _disconnect() async {
    await _client.disconnect();
  }

  void _send(String data) {
    if (!_client.isConnected) return;
    _client.sendInput(data);
  }

  void _sendLine() {
    if (_inputCtrl.text.isEmpty) return;
    _send('${_inputCtrl.text}\r');
    _inputCtrl.clear();
  }

  void _showSnack(String msg) {
    if (!mounted) return;
    ScaffoldMessenger.of(context)
        .showSnackBar(SnackBar(content: Text(msg), duration: const Duration(seconds: 2)));
  }

  @override
  Widget build(BuildContext context) {
    final connected = _client.isConnected;
    return Scaffold(
      body: SafeArea(
        child: Column(
          children: [
            _buildConnectionPanel(connected),
            const Divider(height: 1, color: RttyMobileTheme.border),
            Expanded(child: _buildTerminal()),
            _buildKeybar(connected),
            _buildInputRow(connected),
          ],
        ),
      ),
    );
  }

  Widget _buildConnectionPanel(bool connected) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(12, 12, 12, 8),
      child: Column(
        children: [
          Row(
            children: [
              Expanded(
                child: TextField(
                  controller: _serverCtrl,
                  enabled: !connected,
                  style: const TextStyle(fontFamily: 'monospace', fontSize: 14),
                  decoration: const InputDecoration(
                    labelText: 'SERVER',
                    hintText: '192.168.1.100:8080',
                    isDense: true,
                  ),
                ),
              ),
              const SizedBox(width: 8),
              SizedBox(
                width: 110,
                child: TextField(
                  controller: _tokenCtrl,
                  enabled: !connected,
                  obscureText: true,
                  style: const TextStyle(fontFamily: 'monospace', fontSize: 14),
                  decoration: const InputDecoration(
                    labelText: 'TOKEN',
                    hintText: '可选',
                    isDense: true,
                  ),
                ),
              ),
              const SizedBox(width: 8),
              FilledButton(
                onPressed: connected ? _disconnect : _connect,
                style: FilledButton.styleFrom(
                  backgroundColor: connected
                      ? RttyMobileTheme.danger
                      : RttyMobileTheme.primary,
                  foregroundColor: connected
                      ? Colors.white
                      : RttyMobileTheme.background,
                ),
                child: Text(connected ? '断开' : '连接'),
              ),
            ],
          ),
          const SizedBox(height: 8),
          Row(
            children: [
              Expanded(
                child: TextField(
                  controller: _sessionCtrl,
                  enabled: !connected,
                  style: const TextStyle(fontFamily: 'monospace', fontSize: 14),
                  decoration: const InputDecoration(
                    labelText: 'SESSION',
                    hintText: '留空自动新建',
                    isDense: true,
                  ),
                ),
              ),
              const SizedBox(width: 8),
              Expanded(child: _buildStatus()),
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildStatus() {
    final stateText = switch (_state) {
      ConnState.disconnected => '未连接',
      ConnState.connecting => '连接中…',
      ConnState.connected => '已连接',
      ConnState.error => '连接失败',
    };
    final color = switch (_state) {
      ConnState.connected => RttyMobileTheme.primary,
      ConnState.connecting => RttyMobileTheme.accent,
      ConnState.error => RttyMobileTheme.danger,
      ConnState.disconnected => RttyMobileTheme.textFaint,
    };
    final session = (_sessionId == null || _sessionId!.isEmpty)
        ? ''
        : ' · ${_resumed ? '恢复' : '新建'}:$_sessionId';
    final err = (_state == ConnState.error && _client.error != null)
        ? '\n${_client.error}'
        : '';
    return Text(
      '$stateText$session$err',
      maxLines: 2,
      overflow: TextOverflow.ellipsis,
      style: TextStyle(
        color: color,
        fontSize: 12,
        fontFamily: 'monospace',
      ),
    );
  }

  Widget _buildTerminal() {
    if (!_client.isConnected) {
      final (title, sub) = switch (_state) {
        ConnState.error => (
            '连接失败',
            _client.error ?? '请检查地址、令牌与服务端是否启动',
          ),
        ConnState.connecting => ('连接中', '正在协商 WebSocket 会话…'),
        _ => ('未连接', '输入服务端地址后点击「连接」'),
      };
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(
              Icons.terminal,
              size: 48,
              color: _state == ConnState.error
                  ? RttyMobileTheme.danger
                  : RttyMobileTheme.textFaint,
            ),
            const SizedBox(height: 12),
            Text(title,
                style: TextStyle(
                    color: RttyMobileTheme.textDim,
                    fontSize: 16,
                    fontWeight: FontWeight.w600)),
            const SizedBox(height: 6),
            Text(sub,
                textAlign: TextAlign.center,
                style: const TextStyle(
                    color: RttyMobileTheme.textFaint, fontSize: 12)),
          ],
        ),
      );
    }
    return Container(
      color: RttyMobileTheme.background,
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 8),
      child: ListView.builder(
        controller: _scrollCtrl,
        itemCount: _lines.length,
        itemBuilder: (context, i) => _buildLine(i),
      ),
    );
  }

  Widget _buildLine(int index) {
    final line = index < _lines.length ? _lines[index] : '';
    final mono = const TextStyle(
      fontFamily: 'monospace',
      fontSize: 13,
      height: 1.25,
      color: RttyMobileTheme.text,
    );
    if (index != _cursorY) {
      return SizedBox(height: _lineHeight, child: Text(line, style: mono));
    }

    // 光标行：用高亮色块标出光标位置。
    final x = _cursorX.clamp(0, line.length);
    return SizedBox(
      height: _lineHeight,
      child: Text.rich(
        TextSpan(
          style: mono,
          children: [
            TextSpan(text: line.substring(0, x)),
            if (x < line.length)
              TextSpan(
                text: line[x],
                style: const TextStyle(
                  color: RttyMobileTheme.background,
                  backgroundColor: RttyMobileTheme.primary,
                ),
              )
            else
              const TextSpan(
                text: ' ',
                style: TextStyle(backgroundColor: RttyMobileTheme.primary),
              ),
            if (x + 1 < line.length) TextSpan(text: line.substring(x + 1)),
          ],
        ),
      ),
    );
  }

  Widget _buildKeybar(bool connected) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(12, 8, 12, 0),
      child: Wrap(
        spacing: 6,
        runSpacing: 6,
        children: [
          for (final (label, seq) in _quickKeys)
            _KeyButton(
              label: label,
              onTap: connected ? () => _send(seq) : null,
            ),
        ],
      ),
    );
  }

  Widget _buildInputRow(bool connected) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(12, 8, 12, 12),
      child: Row(
        children: [
          Expanded(
            child: TextField(
              controller: _inputCtrl,
              enabled: connected,
              style: const TextStyle(fontFamily: 'monospace', fontSize: 14),
              textInputAction: TextInputAction.send,
              onSubmitted: (_) => _sendLine(),
              decoration: const InputDecoration(
                hintText: '输入命令，回车发送',
                isDense: true,
              ),
            ),
          ),
          const SizedBox(width: 8),
          FilledButton(
            onPressed: connected ? _sendLine : null,
            child: const Text('发送'),
          ),
        ],
      ),
    );
  }
}

class _KeyButton extends StatelessWidget {
  const _KeyButton({required this.label, this.onTap});

  final String label;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      height: 30,
      child: OutlinedButton(
        onPressed: onTap,
        style: OutlinedButton.styleFrom(
          padding: const EdgeInsets.symmetric(horizontal: 10),
          side: BorderSide(
            color: onTap == null
                ? RttyMobileTheme.border
                : RttyMobileTheme.primaryDim,
          ),
          foregroundColor:
              onTap == null ? RttyMobileTheme.textFaint : RttyMobileTheme.primary,
          textStyle: const TextStyle(fontSize: 11, fontFamily: 'monospace'),
        ),
        child: Text(label),
      ),
    );
  }
}