import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';

import '../data/hub.dart';
import '../theme/theme.dart';
import '../theme/tokens.dart';
import '../widgets/widgets.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 {
    try {
      final events = await HubService.instance.recentEvents(limit: 100);
      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(
      backgroundColor: theme.scaffoldBackgroundColor,
      appBar: AppBar(
        title: const Text('Audit'),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: FaiSpace.lg),
            child: _FilterChips(
              value: _typeFilter,
              onChanged: (v) => setState(() => _typeFilter = v),
            ),
          ),
        ],
      ),
      body: Column(
        children: [
          _LiveStatusBar(eventCount: filtered.length, error: _error),
          Expanded(
            child: !_initialLoaded
                ? const Center(child: CircularProgressIndicator())
                : _error != null && _events.isEmpty
                    ? FaiEmptyState(
                        icon: Icons.cloud_off_outlined,
                        iconColor: theme.colorScheme.error,
                        title: 'Hub unreachable',
                        hint: 'Start the hub with `fai serve`.',
                      )
                    : filtered.isEmpty
                        ? const FaiEmptyState(
                            icon: Icons.timeline_outlined,
                            title: 'No events yet',
                            hint:
                                'Run a flow to populate the audit stream.\nEvents appear here within seconds.',
                          )
                        : ListView.separated(
                            padding: const EdgeInsets.all(FaiSpace.xl),
                            itemCount: filtered.length,
                            separatorBuilder: (_, _) =>
                                const SizedBox(height: FaiSpace.xs),
                            itemBuilder: (context, i) {
                              final e = filtered[i];
                              return FaiDataRow(
                                accent: _toneFor(e.type, theme),
                                leading: _formatTime(e.timestamp),
                                title: e.type,
                                subtitle: _contextLine(e),
                                trailing: e.durationMs != null
                                    ? '${e.durationMs}ms'
                                    : null,
                                onTap: () => showDialog<void>(
                                  context: context,
                                  builder: (_) => _EventDetailDialog(event: e),
                                ),
                              );
                            },
                          ),
          ),
        ],
      ),
    );
  }

  /// Render the event timestamp so the operator never has to
  /// guess what day "21:25" was. Same-day events keep the
  /// compact `HH:mm:ss` form; older events get a `MM-dd` prefix
  /// or a full `YYYY-MM-dd` for last year's tail of the log.
  /// Always rendered in the operator's local time zone — the
  /// dialog still shows the full ISO timestamp for unambiguous
  /// cross-checking.
  String _formatTime(DateTime ts) {
    final local = ts.toLocal();
    final now = DateTime.now();
    final hh = local.hour.toString().padLeft(2, '0');
    final mm = local.minute.toString().padLeft(2, '0');
    final ss = local.second.toString().padLeft(2, '0');
    final time = '$hh:$mm:$ss';
    final sameDay = local.year == now.year &&
        local.month == now.month &&
        local.day == now.day;
    if (sameDay) return time;
    final mo = local.month.toString().padLeft(2, '0');
    final dd = local.day.toString().padLeft(2, '0');
    if (local.year == now.year) return '$mo-$dd $time';
    return '${local.year}-$mo-$dd $time';
  }

  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 FaiColors.warning;
    return theme.colorScheme.outline;
  }
}

class _FilterChips extends StatelessWidget {
  final String value;
  final ValueChanged<String> onChanged;

  const _FilterChips({required this.value, required this.onChanged});

  @override
  Widget build(BuildContext context) {
    const items = [
      ('all', 'all'),
      ('flow.', 'flow'),
      ('step.', 'step'),
      ('module.', 'module'),
    ];
    return Row(
      children: [
        for (final (v, label) in items)
          Padding(
            padding: const EdgeInsets.only(left: FaiSpace.xs),
            child: _ChipButton(
              label: label,
              selected: value == v,
              onTap: () => onChanged(v),
            ),
          ),
      ],
    );
  }
}

class _ChipButton extends StatefulWidget {
  final String label;
  final bool selected;
  final VoidCallback onTap;

  const _ChipButton({
    required this.label,
    required this.selected,
    required this.onTap,
  });

  @override
  State<_ChipButton> createState() => _ChipButtonState();
}

class _ChipButtonState extends State<_ChipButton> {
  bool _hovered = false;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final fg = widget.selected
        ? theme.colorScheme.primary
        : _hovered
            ? theme.colorScheme.onSurface
            : theme.colorScheme.onSurfaceVariant;
    final bg = widget.selected
        ? theme.colorScheme.primary.withValues(alpha: 0.12)
        : _hovered
            ? theme.colorScheme.surfaceContainerHigh
            : Colors.transparent;
    return MouseRegion(
      onEnter: (_) => setState(() => _hovered = true),
      onExit: (_) => setState(() => _hovered = false),
      cursor: SystemMouseCursors.click,
      child: GestureDetector(
        onTap: widget.onTap,
        child: AnimatedContainer(
          duration: FaiMotion.fast,
          padding: const EdgeInsets.symmetric(
            horizontal: FaiSpace.md,
            vertical: 6,
          ),
          decoration: BoxDecoration(
            color: bg,
            borderRadius: BorderRadius.circular(FaiRadius.sm),
            border: Border.all(
              color: widget.selected
                  ? theme.colorScheme.primary.withValues(alpha: 0.3)
                  : Colors.transparent,
            ),
          ),
          child: Text(
            widget.label,
            style: FaiTheme.mono(
              size: 11,
              weight: widget.selected ? FontWeight.w500 : FontWeight.w400,
              color: fg,
            ),
          ),
        ),
      ),
    );
  }
}

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

  const _LiveStatusBar({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: FaiSpace.xl,
        vertical: FaiSpace.sm,
      ),
      decoration: BoxDecoration(
        color: theme.colorScheme.surfaceContainerHigh,
        border: Border(
          bottom: BorderSide(color: theme.colorScheme.outlineVariant),
        ),
      ),
      child: Row(
        children: [
          FaiStatusDot(
            color: live ? FaiColors.success : FaiColors.danger,
            pulsing: live,
          ),
          const SizedBox(width: FaiSpace.sm),
          Text(
            live
                ? 'live · polling 2s · $eventCount event${eventCount == 1 ? '' : 's'}'
                : 'disconnected · $error',
            style: theme.textTheme.bodySmall?.copyWith(
              color: theme.colorScheme.onSurfaceVariant,
            ),
          ),
          const Spacer(),
          if (live)
            Row(
              children: [
                Icon(
                  Icons.shield_outlined,
                  size: 12,
                  color: theme.colorScheme.primary,
                ),
                const SizedBox(width: 4),
                Text(
                  'hash chain verified',
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.colorScheme.primary,
                    fontWeight: FontWeight.w500,
                  ),
                ),
              ],
            ),
        ],
      ),
    );
  }
}

class _EventDetailDialog extends StatefulWidget {
  final AuditEvent event;

  const _EventDetailDialog({required this.event});

  @override
  State<_EventDetailDialog> createState() => _EventDetailDialogState();
}

class _EventDetailDialogState extends State<_EventDetailDialog> {
  AskAiResult? _explanation;
  bool _explaining = false;
  SystemAiStatus? _aiStatus;

  AuditEvent get event => widget.event;

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

  Future<void> _loadAiStatus() async {
    try {
      final s = await HubService.instance.systemAiStatus();
      if (!mounted) return;
      setState(() => _aiStatus = s);
    } catch (_) {
      // Stay null → "Explain" stays hidden.
    }
  }

  Future<void> _explain() async {
    setState(() {
      _explaining = true;
      _explanation = null;
    });
    final prompt = _buildPrompt(event, _aiStatus?.privacyMode ?? 'off');
    final result = await HubService.instance.askAi(prompt);
    if (!mounted) return;
    setState(() {
      _explaining = false;
      _explanation = result;
    });
  }

  String _buildPrompt(AuditEvent e, String mode) {
    // Privacy: redacted = no detail JSON, full = include it.
    final buf = StringBuffer()
      ..writeln('A F∆I Platform audit event was logged. Explain what')
      ..writeln('happened in plain language and suggest one concrete')
      ..writeln('fix the operator can apply now.')
      ..writeln()
      ..writeln('event_type: ${e.type}')
      ..writeln('flow: ${e.flowName ?? "(none)"}')
      ..writeln('step: ${e.stepId ?? "(none)"}')
      ..writeln('module: ${e.moduleName ?? "(none)"}'
          '${e.moduleVersion != null ? "@${e.moduleVersion}" : ""}')
      ..writeln('error: ${e.error ?? "(none)"}')
      ..writeln('duration: ${e.durationMs ?? 0}ms');
    if (mode == 'full' && e.detail != null) {
      buf
        ..writeln()
        ..writeln('detail:')
        ..writeln(e.detail);
    }
    return buf.toString();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    String prettyDetail() {
      final raw = event.detail;
      if (raw == null || raw.isEmpty) return '';
      // Many detail strings are JSON; try to pretty-print and
      // fall back to the raw value when parsing fails.
      try {
        final dynamic parsed = const JsonDecoder().convert(raw);
        return const JsonEncoder.withIndent('  ').convert(parsed);
      } catch (_) {
        return raw;
      }
    }

    final detail = prettyDetail();
    return AlertDialog(
      title: Text(event.type),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(FaiRadius.md),
      ),
      content: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 640, maxHeight: 560),
        child: SingleChildScrollView(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisSize: MainAxisSize.min,
            children: [
              _Field(label: 'event_id', value: event.eventId, mono: true),
              _Field(
                label: 'timestamp',
                value: event.timestamp.toIso8601String(),
                mono: true,
              ),
              if (event.flowName != null)
                _Field(label: 'flow', value: event.flowName!),
              if (event.flowExecution != null)
                _Field(
                  label: 'flow_execution',
                  value: event.flowExecution!,
                  mono: true,
                ),
              if (event.invocationId != null)
                _Field(
                  label: 'invocation_id',
                  value: event.invocationId!,
                  mono: true,
                ),
              if (event.stepId != null)
                _Field(label: 'step', value: event.stepId!),
              if (event.moduleName != null)
                _Field(
                  label: 'module',
                  value: event.moduleVersion != null
                      ? '${event.moduleName} @ ${event.moduleVersion}'
                      : event.moduleName!,
                ),
              if (event.durationMs != null)
                _Field(label: 'duration', value: '${event.durationMs} ms'),
              if (event.error != null)
                _Field(
                  label: 'error',
                  value: event.error!,
                  valueColor: theme.colorScheme.error,
                ),
              if (detail.isNotEmpty) ...[
                const SizedBox(height: FaiSpace.md),
                Text(
                  'DETAIL',
                  style: theme.textTheme.labelSmall?.copyWith(
                    color: theme.colorScheme.onSurfaceVariant,
                    letterSpacing: 0.6,
                  ),
                ),
                const SizedBox(height: 4),
                Container(
                  width: double.infinity,
                  padding: const EdgeInsets.all(FaiSpace.md),
                  decoration: BoxDecoration(
                    color: theme.colorScheme.surfaceContainerHigh,
                    borderRadius: BorderRadius.circular(FaiRadius.sm),
                    border: Border.all(
                      color: theme.colorScheme.outlineVariant,
                    ),
                  ),
                  child: SelectableText(
                    detail,
                    style: FaiTheme.mono(size: 11),
                  ),
                ),
              ],
              if (_explanation != null || _explaining) ...[
                const SizedBox(height: FaiSpace.lg),
                _ExplanationPanel(
                  explaining: _explaining,
                  result: _explanation,
                  privacyMode: _aiStatus?.privacyMode ?? 'off',
                ),
              ],
            ],
          ),
        ),
      ),
      actions: [
        if (_aiStatus?.enabled == true && (event.error != null))
          OutlinedButton.icon(
            onPressed: _explaining ? null : _explain,
            icon: const Icon(Icons.auto_awesome, size: 16),
            label: Text(
              _explaining
                  ? 'Asking…'
                  : _explanation == null
                      ? 'Explain'
                      : 'Re-ask',
            ),
          )
        else if (_aiStatus != null && !_aiStatus!.enabled && (event.error != null))
          Tooltip(
            message: 'Configure System AI in Settings (Cmd+,)',
            child: OutlinedButton.icon(
              onPressed: null,
              icon: const Icon(Icons.auto_awesome_outlined, size: 16),
              label: const Text('Explain'),
            ),
          ),
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Close'),
        ),
      ],
    );
  }
}

class _Field extends StatelessWidget {
  final String label;
  final String value;
  final bool mono;
  final Color? valueColor;

  const _Field({
    required this.label,
    required this.value,
    this.mono = false,
    this.valueColor,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Padding(
      padding: const EdgeInsets.only(bottom: 6),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 110,
            child: Text(
              label,
              style: theme.textTheme.labelSmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
          ),
          Expanded(
            child: SelectableText(
              value,
              style: mono
                  ? FaiTheme.mono(
                      size: 11,
                      color: valueColor ?? theme.colorScheme.onSurface,
                    )
                  : theme.textTheme.bodySmall?.copyWith(
                      color: valueColor ?? theme.colorScheme.onSurface,
                    ),
            ),
          ),
        ],
      ),
    );
  }
}

class _ExplanationPanel extends StatelessWidget {
  final bool explaining;
  final AskAiResult? result;
  final String privacyMode;

  const _ExplanationPanel({
    required this.explaining,
    required this.result,
    required this.privacyMode,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final ok = result?.isSuccess ?? false;
    final color = explaining
        ? theme.colorScheme.primary
        : ok
            ? theme.colorScheme.primary
            : theme.colorScheme.error;
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(FaiSpace.md),
      decoration: BoxDecoration(
        color: theme.colorScheme.surfaceContainerHigh,
        borderRadius: BorderRadius.circular(FaiRadius.sm),
        border: Border.all(color: color.withValues(alpha: 0.3)),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Icon(Icons.auto_awesome, size: 14, color: color),
              const SizedBox(width: FaiSpace.xs),
              Text(
                'SYSTEM AI',
                style: theme.textTheme.labelSmall?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant,
                  letterSpacing: 0.6,
                ),
              ),
              const SizedBox(width: FaiSpace.xs),
              FaiPill(
                label: privacyMode,
                tone: privacyMode == 'full'
                    ? FaiPillTone.warning
                    : FaiPillTone.neutral,
              ),
              const Spacer(),
              if (result != null && result!.isSuccess && result!.latencyMs > 0)
                Text(
                  '${result!.latencyMs} ms',
                  style: FaiTheme.mono(
                    size: 10,
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ),
            ],
          ),
          const SizedBox(height: FaiSpace.sm),
          if (explaining)
            Row(
              children: [
                const SizedBox(
                  width: 14,
                  height: 14,
                  child: CircularProgressIndicator(strokeWidth: 2),
                ),
                const SizedBox(width: FaiSpace.sm),
                Text(
                  'Asking the configured System AI…',
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            )
          else if (result != null) ...[
            SelectableText(
              result!.text,
              style: theme.textTheme.bodyMedium?.copyWith(
                color: ok ? theme.colorScheme.onSurface : theme.colorScheme.error,
              ),
            ),
            if (result!.fixHint.isNotEmpty) ...[
              const SizedBox(height: FaiSpace.sm),
              Text(
                'FIX',
                style: theme.textTheme.labelSmall?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant,
                  letterSpacing: 0.6,
                ),
              ),
              const SizedBox(height: 2),
              Text(
                result!.fixHint,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.onSurface,
                ),
              ),
            ],
          ],
        ],
      ),
    );
  }
}