import 'dart:async';

import 'package:flutter/material.dart';

import '../data/hub.dart';

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

  @override
  State<AuditPage> createState() => _AuditPageState();
}

class _AuditPageState extends State<AuditPage> {
  String _typeFilter = 'all';
  List<AuditEvent> _events = const [];
  String? _error;
  bool _initialLoaded = false;
  Timer? _poller;

  @override
  void initState() {
    super.initState();
    _refresh();
    _poller = Timer.periodic(
      const Duration(seconds: 2),
      (_) => _refresh(),
    );
  }

  @override
  void dispose() {
    _poller?.cancel();
    super.dispose();
  }

  Future<void> _refresh() async {
    final types = _typeFilter == 'all'
        ? <String>[]
        : <String>[]; // server-side filter not yet — clientside below
    try {
      final events = await HubService.instance.recentEvents(
        limit: 100,
        types: types,
      );
      if (!mounted) return;
      setState(() {
        _events = events;
        _error = null;
        _initialLoaded = true;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _error = e.toString();
        _initialLoaded = true;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final filtered = _typeFilter == 'all'
        ? _events
        : _events.where((e) => e.type.startsWith(_typeFilter)).toList();

    return Scaffold(
      appBar: AppBar(
        title: const Text('Audit Stream'),
        centerTitle: false,
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: 16),
            child: DropdownButton<String>(
              value: _typeFilter,
              onChanged: (v) => setState(() => _typeFilter = v ?? 'all'),
              items: const [
                DropdownMenuItem(value: 'all', child: Text('all events')),
                DropdownMenuItem(value: 'flow.', child: Text('flow.*')),
                DropdownMenuItem(value: 'step.', child: Text('step.*')),
                DropdownMenuItem(value: 'module.', child: Text('module.*')),
              ],
            ),
          ),
        ],
      ),
      body: Column(
        children: [
          _StatusBar(eventCount: filtered.length, error: _error),
          Expanded(
            child: !_initialLoaded
                ? const Center(child: CircularProgressIndicator())
                : _error != null && _events.isEmpty
                ? Center(
                    child: Padding(
                      padding: const EdgeInsets.all(32),
                      child: Text(
                        'Hub unreachable: $_error\n\n'
                        'Start the hub with `fai serve`.',
                        textAlign: TextAlign.center,
                        style: theme.textTheme.bodyMedium,
                      ),
                    ),
                  )
                : filtered.isEmpty
                ? Center(
                    child: Text(
                      '(no events yet)',
                      style: theme.textTheme.bodyMedium?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                  )
                : ListView.separated(
                    padding: const EdgeInsets.all(24),
                    itemCount: filtered.length,
                    separatorBuilder: (_, _) =>
                        const SizedBox(height: 8),
                    itemBuilder: (context, i) {
                      final e = filtered[i];
                      final ts = e.timestamp;
                      final tsStr =
                          '${ts.hour.toString().padLeft(2, '0')}:${ts.minute.toString().padLeft(2, '0')}:${ts.second.toString().padLeft(2, '0')}';
                      return Card(
                        elevation: 0,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(8),
                          side: BorderSide(
                            color: theme.colorScheme.outlineVariant,
                          ),
                        ),
                        child: Padding(
                          padding: const EdgeInsets.symmetric(
                            horizontal: 16,
                            vertical: 12,
                          ),
                          child: Row(
                            children: [
                              Container(
                                width: 4,
                                height: 32,
                                decoration: BoxDecoration(
                                  color: _toneFor(e.type, theme),
                                  borderRadius: BorderRadius.circular(2),
                                ),
                              ),
                              const SizedBox(width: 12),
                              SizedBox(
                                width: 90,
                                child: Text(
                                  tsStr,
                                  style:
                                      theme.textTheme.bodySmall?.copyWith(
                                    fontFamily: 'monospace',
                                    color: theme
                                        .colorScheme.onSurfaceVariant,
                                  ),
                                ),
                              ),
                              SizedBox(
                                width: 180,
                                child: Text(
                                  e.type,
                                  style:
                                      theme.textTheme.bodyMedium?.copyWith(
                                    fontFamily: 'monospace',
                                    fontWeight: FontWeight.w500,
                                  ),
                                ),
                              ),
                              Expanded(
                                child: Text(
                                  _contextLine(e),
                                  style:
                                      theme.textTheme.bodyMedium?.copyWith(
                                    color: theme
                                        .colorScheme.onSurfaceVariant,
                                  ),
                                ),
                              ),
                              if (e.durationMs != null)
                                Text(
                                  '${e.durationMs}ms',
                                  style:
                                      theme.textTheme.bodySmall?.copyWith(
                                    fontFamily: 'monospace',
                                    color: theme
                                        .colorScheme.onSurfaceVariant,
                                  ),
                                ),
                            ],
                          ),
                        ),
                      );
                    },
                  ),
          ),
        ],
      ),
    );
  }

  String _contextLine(AuditEvent e) {
    final parts = <String>[];
    if (e.flowName != null) parts.add(e.flowName!);
    if (e.stepId != null) parts.add(':${e.stepId}');
    if (e.moduleName != null) parts.add('  via ${e.moduleName}');
    if (e.error != null) parts.add('  [error: ${e.error}]');
    return parts.join('');
  }

  Color _toneFor(String type, ThemeData theme) {
    if (type.endsWith('.failed')) return theme.colorScheme.error;
    if (type.endsWith('.completed')) return theme.colorScheme.primary;
    if (type.endsWith('.started')) return theme.colorScheme.tertiary;
    return theme.colorScheme.outline;
  }
}

class _StatusBar extends StatelessWidget {
  final int eventCount;
  final String? error;

  const _StatusBar({required this.eventCount, required this.error});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final live = error == null;
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 8),
      color: theme.colorScheme.surfaceContainerHigh,
      child: Row(
        children: [
          Icon(
            Icons.fiber_manual_record,
            size: 12,
            color: live ? theme.colorScheme.tertiary : theme.colorScheme.error,
          ),
          const SizedBox(width: 8),
          Text(
            live
                ? 'live (polling 2s) — $eventCount events'
                : 'disconnected — $error',
            style: theme.textTheme.bodySmall,
          ),
        ],
      ),
    );
  }
}