import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:stacked/stacked.dart';

import '../../about/external/initial/SystemdSpec.dart';
import '../../about/internal/application/ServerProfile.dart';
import '../../about/internal/application/StepTracker.dart';
import '../../about/internal/application/TextType.dart';
import '../../comms/Comms.dart' show DeployResult, LogLine;
import '../../designs/LogConsole.dart';
import '../../designs/StepList.dart';
import '../../designs/text/Text.dart';
import '../../utils/Colors.dart';
import 'ConnectSystemd.dart';
import 'Systemd.dart';
import 'ViewSystemd.dart';

class SystemdState extends State<Systemd> implements ConnectSystemd {
  static const _dependencyOptions = {
    'mariadb.service': 'MariaDB',
    'mysql.service': 'MySQL',
    'postgresql.service': 'PostgreSQL',
    'docker.service': 'Docker',
    'redis.service': 'Redis',
    'nginx.service': 'nginx',
  };

  ViewSystemd? _model;

  StreamSubscription<LogLine>? _logSub;
  StreamSubscription<List<DeployStep>>? _stepSub;

  final _lines = <LogLine>[];
  List<DeployStep> _steps = [];
  bool _applying = false;
  DeployResult? _result;

  late final TextEditingController _name;
  late final TextEditingController _description;
  late final TextEditingController _user;
  late final TextEditingController _workDir;
  late final TextEditingController _exec;
  late final TextEditingController _restartSec;
  late final TextEditingController _environment;

  SystemdType _type = SystemdType.simple;
  RestartPolicy _restart = RestartPolicy.onFailure;
  final Set<String> _after = {};
  bool _javaExit = false;
  bool _enableOnBoot = true;
  bool _startNow = true;

  ServerProfile get _server => widget.server;

  @override
  void initState() {
    super.initState();
    final service = widget.service;
    final isJar = service != null && !service.isWeb;
    final jarPath = service == null
        ? '/opt/app/app.jar'
        : service.remotePath(
            service.remoteJarName.trim().isEmpty
                ? 'app.jar'
                : service.remoteJarName,
          );

    _name = TextEditingController(
      text: service?.serviceName.trim().isNotEmpty == true
          ? service!.serviceName.trim()
          : (service?.name ?? 'myapp'),
    );
    _description = TextEditingController(
      text: 'Peach · ${service?.name ?? 'service'}',
    );
    _user = TextEditingController(text: _server.username);
    _workDir = TextEditingController(text: service?.remoteRoot ?? '/opt/app');
    _exec = TextEditingController(
      text: isJar ? '/usr/bin/java -jar $jarPath' : '',
    );
    _restartSec = TextEditingController(text: '5');
    _environment = TextEditingController();
    _javaExit = isJar;
  }

  @override
  void dispose() {
    _logSub?.cancel();
    _stepSub?.cancel();
    for (final c in [
      _name,
      _description,
      _user,
      _workDir,
      _exec,
      _restartSec,
      _environment,
    ]) {
      c.dispose();
    }
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ViewModelBuilder<ViewSystemd>.reactive(
      viewModelBuilder: () => ViewSystemd(context, this),
      onViewModelReady: _onReady,
      builder: (context, viewModel, child) => Scaffold(
        appBar: AppBar(
          title: text(
            'Register systemd service',
            20,
            TextType.Bold,
            color: context.jp.text,
          ),
        ),
        body: ListView(
          padding: const EdgeInsets.fromLTRB(20, 18, 20, 40),
          children: [
            _sectionTitle('1 · Unit', Icons.badge_outlined),
            _field('Unit name', _name, hint: 'orders  →  orders.service'),
            _field('Description', _description),
            Row(
              children: [
                Expanded(child: _typeDropdown()),
                const SizedBox(width: 12),
                Expanded(child: _restartDropdown()),
              ],
            ),
            const SizedBox(height: 12),
            _sectionTitle('2 · Process', Icons.terminal),
            _field('User', _user),
            _field('Working directory', _workDir, hint: '/opt/app'),
            _field(
              'ExecStart',
              _exec,
              hint: '/usr/bin/java -jar /opt/app/app.jar',
              mono: true,
            ),
            Row(
              children: [
                SizedBox(
                  width: 130,
                  child: _field(
                    'RestartSec',
                    _restartSec,
                    keyboard: TextInputType.number,
                  ),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: SwitchListTile(
                    contentPadding: EdgeInsets.zero,
                    dense: true,
                    value: _javaExit,
                    onChanged: _onJavaExitChanged,
                    title: text(
                      'JVM SuccessExitStatus=143',
                      14,
                      TextType.Regular,
                      color: context.jp.text,
                    ),
                  ),
                ),
              ],
            ),
            _field(
              'Environment (KEY=VALUE per line)',
              _environment,
              hint: 'SPRING_PROFILES_ACTIVE=prod\nJAVA_OPTS=-Xmx512m',
              mono: true,
              lines: 3,
            ),
            const SizedBox(height: 12),
            _sectionTitle('3 · Dependencies', Icons.account_tree),
            text(
              'Starts after network.target',
              12,
              TextType.Regular,
              color: context.jp.textFaint,
            ),
            const SizedBox(height: 8),
            _dependencyChips(),
            const SizedBox(height: 12),
            SwitchListTile(
              contentPadding: EdgeInsets.zero,
              value: _enableOnBoot,
              onChanged: _onEnableChanged,
              title: text(
                'Enable on boot',
                14,
                TextType.Regular,
                color: context.jp.text,
              ),
              subtitle: text(
                'systemctl enable',
                12,
                TextType.Light,
                color: context.jp.textDim,
              ),
            ),
            SwitchListTile(
              contentPadding: EdgeInsets.zero,
              value: _startNow,
              onChanged: _onStartNowChanged,
              title: text(
                'Start now',
                14,
                TextType.Regular,
                color: context.jp.text,
              ),
              subtitle: text(
                'systemctl restart after install',
                12,
                TextType.Light,
                color: context.jp.textDim,
              ),
            ),
            const SizedBox(height: 16),
            _sectionTitle('4 · Preview & confirm', Icons.rule),
            _previewCard(_spec()),
            const SizedBox(height: 10),
            _plannedCommands(_spec()),
            const SizedBox(height: 14),
            FilledButton.icon(
              onPressed: _applying ? null : _onApply,
              icon: _applying
                  ? SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(
                        strokeWidth: 2,
                        color: colorWhite,
                      ),
                    )
                  : const Icon(Icons.check_circle),
              label: text(
                _applying ? 'Registering…' : 'Install & register unit',
                14,
                TextType.Bold,
                color: colorWhite,
              ),
            ),
            if (_steps.isNotEmpty) ...[
              const SizedBox(height: 16),
              StepList(steps: _steps),
            ],
            if (_result != null) ...[
              const SizedBox(height: 14),
              _resultBanner(_result!),
            ],
            if (_lines.isNotEmpty) ...[
              const SizedBox(height: 14),
              LogConsole(
                logs: _lines,
                height: 260,
                onClear: _onClearLogs,
                onCopy: _onCopyLogs,
              ),
            ],
          ],
        ),
      ),
    );
  }

  void _onReady(ViewSystemd model) {
    _model = model;
    // onViewModelReady fires mid-build; a synchronous setState from the
    // first load would dirty this State while it is still being built.
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) _initiate();
    });
  }

  Future<void> _initiate() async {
    _logSub = _model?.logs.listen(_onLogLine);
    _stepSub = _model?.steps.listen(_onSteps);
  }

  void _onLogLine(LogLine line) {
    if (!mounted) return;
    setState(() => _lines.add(line));
  }

  void _onSteps(List<DeployStep> steps) {
    if (!mounted) return;
    setState(() => _steps = steps);
  }

  SystemdSpec _spec() => SystemdSpec(
    unitName: _name.text,
    description: _description.text,
    type: _type,
    user: _user.text,
    workingDirectory: _workDir.text,
    execStart: _exec.text,
    restart: _restart,
    restartSec: int.tryParse(_restartSec.text) ?? 5,
    environmentLines: _environment.text,
    afterUnits: ['network.target', ..._after],
    javaSuccessExit: _javaExit,
    enableOnBoot: _enableOnBoot,
    startNow: _startNow,
  );

  // ── named handlers ─────────────────────────────────────────────────────────

  void _onApply() {
    final spec = _spec();
    if (spec.safeName.isEmpty) {
      _notify('Enter a unit name.');
      return;
    }
    if (spec.execStart.trim().isEmpty) {
      _notify('Enter an ExecStart command.');
      return;
    }
    setState(() {
      _applying = true;
      _lines.clear();
      _result = null;
    });
    _model?.installUnit(_server, spec, widget.service);
  }

  void _onTypeChanged(SystemdType? v) =>
      setState(() => _type = v ?? SystemdType.simple);

  void _onRestartChanged(RestartPolicy? v) =>
      setState(() => _restart = v ?? RestartPolicy.onFailure);

  void _onJavaExitChanged(bool v) => setState(() => _javaExit = v);

  void _onEnableChanged(bool v) => setState(() => _enableOnBoot = v);

  void _onStartNowChanged(bool v) => setState(() => _startNow = v);

  void _onDependencyChanged(String unit, bool selected) {
    setState(() {
      if (selected) {
        _after.add(unit);
      } else {
        _after.remove(unit);
      }
    });
  }

  /// The preview re-renders from the live field values, so every keystroke
  /// has to repaint.
  void _onFieldChanged(String _) => setState(() {});

  void _onCopyUnit(SystemdSpec spec) {
    Clipboard.setData(ClipboardData(text: spec.render()));
    _notify('Unit file copied.');
  }

  void _onClearLogs() => setState(() => _lines.clear());

  void _onCopyLogs() {
    Clipboard.setData(
      ClipboardData(text: _lines.map((l) => l.text).join('\n')),
    );
    _notify('Logs copied.');
  }

  void _notify(String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }

  // ── ConnectSystemd ─────────────────────────────────────────────────────────

  @override
  void onUnitInstalled(DeployResult result) {
    if (!mounted) return;
    setState(() {
      _applying = false;
      _result = result;
    });
  }

  // ── screen-only widgets ────────────────────────────────────────────────────

  Widget _sectionTitle(String title, IconData icon) => Padding(
    padding: const EdgeInsets.only(top: 10, bottom: 10),
    child: Row(
      children: [
        Icon(icon, size: 16, color: PeachTheme.seed),
        const SizedBox(width: 8),
        text(
          title.toUpperCase(),
          12.5,
          TextType.Bold,
          color: context.jp.text,
          letterSpacing: 0.8,
        ),
      ],
    ),
  );

  Widget _field(
    String label,
    TextEditingController controller, {
    String? hint,
    bool mono = false,
    int lines = 1,
    TextInputType? keyboard,
  }) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 12),
      child: TextField(
        controller: controller,
        maxLines: lines,
        keyboardType: keyboard,
        onChanged: _onFieldChanged,
        style: mono
            ? const TextStyle(fontFamily: 'monospace', fontSize: 13)
            : null,
        decoration: InputDecoration(labelText: label, hintText: hint),
      ),
    );
  }

  Widget _typeDropdown() => DropdownButtonFormField<SystemdType>(
    initialValue: _type,
    decoration: const InputDecoration(labelText: 'Type'),
    items: SystemdType.values
        .map((t) => DropdownMenuItem(value: t, child: Text(t.name)))
        .toList(),
    onChanged: _onTypeChanged,
  );

  Widget _restartDropdown() => DropdownButtonFormField<RestartPolicy>(
    initialValue: _restart,
    decoration: const InputDecoration(labelText: 'Restart'),
    items: RestartPolicy.values
        .map((r) => DropdownMenuItem(value: r, child: Text(r.label)))
        .toList(),
    onChanged: _onRestartChanged,
  );

  Widget _dependencyChips() {
    final jp = context.jp;
    return Wrap(
      spacing: 8,
      runSpacing: 8,
      children: _dependencyOptions.entries.map((entry) {
        final on = _after.contains(entry.key);
        return FilterChip(
          label: Text(entry.value),
          selected: on,
          onSelected: (s) => _onDependencyChanged(entry.key, s),
          showCheckmark: false,
          selectedColor: PeachTheme.seed.withValues(alpha: 0.20),
          backgroundColor: jp.surface2,
          side: BorderSide(color: on ? PeachTheme.seed : jp.border),
          labelStyle: TextStyle(
            color: on ? PeachTheme.seed : jp.textDim,
            fontWeight: FontWeight.w600,
          ),
        );
      }).toList(),
    );
  }

  Widget _previewCard(SystemdSpec spec) {
    final jp = context.jp;
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: jp.consoleBg,
        borderRadius: BorderRadius.circular(14),
        border: Border.all(color: ConsoleColors.frame),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              const Icon(Icons.description, size: 15, color: PeachTheme.seed),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  '/etc/systemd/system/${spec.safeName}.service',
                  style: const TextStyle(
                    fontFamily: 'monospace',
                    fontSize: 12,
                    color: ConsoleColors.header,
                  ),
                ),
              ),
              IconButton(
                tooltip: 'Copy',
                iconSize: 15,
                color: ConsoleColors.header,
                onPressed: () => _onCopyUnit(spec),
                icon: const Icon(Icons.copy_all),
              ),
            ],
          ),
          const Divider(color: ConsoleColors.frame),
          SelectableText(
            spec.render(),
            style: const TextStyle(
              fontFamily: 'monospace',
              fontSize: 12.5,
              height: 1.4,
              color: ConsoleColors.body,
            ),
          ),
        ],
      ),
    );
  }

  Widget _plannedCommands(SystemdSpec spec) {
    final jp = context.jp;
    final commands = spec.plannedCommands(sudo: _server.useSudo);
    return Container(
      padding: const EdgeInsets.all(14),
      decoration: PeachTheme.panel(context, radius: 14),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          text(
            'THESE COMMANDS WILL RUN',
            11,
            TextType.Bold,
            color: jp.textDim,
            letterSpacing: 0.8,
          ),
          const SizedBox(height: 8),
          for (final command in commands)
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 2),
              child: Row(
                children: [
                  Icon(Icons.chevron_right, size: 15, color: jp.textFaint),
                  const SizedBox(width: 4),
                  Expanded(
                    child: text(
                      command,
                      12.5,
                      TextType.Regular,
                      color: jp.textDim,
                    ),
                  ),
                ],
              ),
            ),
        ],
      ),
    );
  }

  Widget _resultBanner(DeployResult result) {
    final color = result.ok ? PeachTheme.seed : PeachTheme.danger;
    return Container(
      padding: const EdgeInsets.fromLTRB(14, 12, 12, 12),
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.10),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: color.withValues(alpha: 0.5)),
      ),
      child: Row(
        children: [
          Icon(result.ok ? Icons.check_circle : Icons.error, color: color),
          const SizedBox(width: 10),
          Expanded(
            child: text(result.message, 14, TextType.Regular, color: color),
          ),
        ],
      ),
    );
  }
}