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

import '../../models/announcement.dart';
import '../../providers/announcements_provider.dart';
import '../../theme/m3_motion.dart';
import '../../utils/app_time.dart';
import '../../utils/snackbar.dart';
import '../../widgets/app_breakpoints.dart';

/// All user roles available for announcement visibility.
const _allRoles = ['admin', 'dispatcher', 'programmer', 'it_staff', 'standard'];

/// Default visible roles (standard is excluded by default).
const _defaultVisibleRoles = ['admin', 'dispatcher', 'programmer', 'it_staff'];

/// Human-readable labels for each role.
const _roleLabels = {
  'admin': 'Admin',
  'dispatcher': 'Dispatcher',
  'programmer': 'Programmer',
  'it_staff': 'IT Staff',
  'standard': 'Standard',
};

/// Push notification interval options (minutes → display label).
/// [null] means no scheduled push.
const _pushIntervalOptions = [
  (null, 'No scheduled push'),
  (1, 'Every minute'),
  (5, 'Every 5 minutes'),
  (10, 'Every 10 minutes'),
  (15, 'Every 15 minutes'),
  (30, 'Every 30 minutes'),
  (60, 'Every hour'),
  (120, 'Every 2 hours'),
  (360, 'Every 6 hours'),
  (720, 'Every 12 hours'),
  (1440, 'Daily'),
];

String _formatDt(DateTime dt) =>
    '${AppTime.formatDate(dt)}  ${AppTime.formatTime(dt)}';

/// Picks a date+time using the platform date and time pickers.
/// Returns a Manila-timezone [DateTime] or [null] if cancelled.
Future<DateTime?> pickDateTime(
  BuildContext context, {
  DateTime? initial,
}) async {
  final now = AppTime.now();
  final startDate = initial ?? now;

  final date = await showDatePicker(
    context: context,
    initialDate: startDate,
    firstDate: now.subtract(const Duration(days: 1)),
    lastDate: now.add(const Duration(days: 365)),
  );
  if (date == null || !context.mounted) return null;

  final time = await showTimePicker(
    context: context,
    initialTime: TimeOfDay.fromDateTime(initial ?? now),
  );
  if (time == null) return null;

  return AppTime.fromComponents(
    year: date.year,
    month: date.month,
    day: date.day,
    hour: time.hour,
    minute: time.minute,
  );
}

/// Shows the create/edit announcement dialog.
///
/// On mobile, uses a full-screen bottom sheet; on desktop, a centered dialog.
Future<void> showCreateAnnouncementDialog(
  BuildContext context, {
  Announcement? editing,
}) async {
  final width = MediaQuery.sizeOf(context).width;
  if (width < AppBreakpoints.tablet) {
    await m3ShowBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      builder: (ctx) => _CreateAnnouncementContent(editing: editing),
    );
  } else {
    await m3ShowDialog<void>(
      context: context,
      builder: (ctx) => Dialog(
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 560),
          child: _CreateAnnouncementContent(editing: editing),
        ),
      ),
    );
  }
}

/// Shows a focused dialog to edit only the banner settings of an announcement.
Future<void> showBannerSettingsDialog(
  BuildContext context, {
  required Announcement announcement,
}) async {
  final width = MediaQuery.sizeOf(context).width;
  if (width < AppBreakpoints.tablet) {
    await m3ShowBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      builder: (ctx) => _BannerSettingsContent(announcement: announcement),
    );
  } else {
    await m3ShowDialog<void>(
      context: context,
      builder: (ctx) => Dialog(
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 480),
          child: _BannerSettingsContent(announcement: announcement),
        ),
      ),
    );
  }
}

// ─────────────────────────────────────────────────────────────────────────────
// Create / Edit dialog
// ─────────────────────────────────────────────────────────────────────────────

class _CreateAnnouncementContent extends ConsumerStatefulWidget {
  const _CreateAnnouncementContent({this.editing});

  final Announcement? editing;

  @override
  ConsumerState<_CreateAnnouncementContent> createState() =>
      _CreateAnnouncementContentState();
}

class _CreateAnnouncementContentState
    extends ConsumerState<_CreateAnnouncementContent> {
  late final TextEditingController _titleCtrl;
  late final TextEditingController _bodyCtrl;
  late Set<String> _selectedRoles;
  bool _isTemplate = false;
  bool _submitting = false;

  // Template selection
  String? _selectedTemplateId;

  // Banner state
  bool _bannerEnabled = false;
  bool _bannerShowImmediately = true; // false = custom date/time
  DateTime? _bannerShowAt;
  bool _bannerHideManual = true; // false = auto hide at custom date/time
  DateTime? _bannerHideAt;
  int? _pushIntervalMinutes; // null = no scheduled push

  @override
  void initState() {
    super.initState();
    final source = widget.editing;
    _titleCtrl = TextEditingController(text: source?.title ?? '');
    _bodyCtrl = TextEditingController(text: source?.body ?? '');
    _selectedRoles = source != null
        ? Set<String>.from(source.visibleRoles)
        : Set<String>.from(_defaultVisibleRoles);
    _isTemplate = widget.editing?.isTemplate ?? false;

    // Banner initialisation from existing data
    _bannerEnabled = source?.bannerEnabled ?? false;
    _bannerShowAt = source?.bannerShowAt;
    _bannerShowImmediately = source?.bannerShowAt == null;
    _bannerHideAt = source?.bannerHideAt;
    _bannerHideManual = source?.bannerHideAt == null;
    _pushIntervalMinutes = source?.pushIntervalMinutes;
  }

  @override
  void dispose() {
    _titleCtrl.dispose();
    _bodyCtrl.dispose();
    super.dispose();
  }

  bool get _canSubmit {
    final hasContent =
        _titleCtrl.text.trim().isNotEmpty && _bodyCtrl.text.trim().isNotEmpty;
    final hasRoles = _selectedRoles.isNotEmpty;
    return hasContent && hasRoles && !_submitting;
  }

  void _applyTemplate(Announcement template) {
    setState(() {
      _selectedTemplateId = template.id;
      _titleCtrl.text = template.title;
      _bodyCtrl.text = template.body;
      _selectedRoles = Set<String>.from(template.visibleRoles);
    });
  }

  void _clearTemplate() {
    setState(() {
      _selectedTemplateId = null;
    });
  }

  Future<void> _pickShowAt() async {
    final dt = await pickDateTime(context, initial: _bannerShowAt);
    if (dt != null) setState(() => _bannerShowAt = dt);
  }

  Future<void> _pickHideAt() async {
    final dt = await pickDateTime(context, initial: _bannerHideAt);
    if (dt != null) setState(() => _bannerHideAt = dt);
  }

  Future<void> _submit() async {
    if (!_canSubmit) return;
    setState(() => _submitting = true);
    try {
      final ctrl = ref.read(announcementsControllerProvider);
      final showAt = _bannerEnabled && !_bannerShowImmediately ? _bannerShowAt : null;
      final hideAt = _bannerEnabled && !_bannerHideManual ? _bannerHideAt : null;
      final interval = _bannerEnabled ? _pushIntervalMinutes : null;

      if (widget.editing != null) {
        await ctrl.updateAnnouncement(
          id: widget.editing!.id,
          title: _titleCtrl.text.trim(),
          body: _bodyCtrl.text.trim(),
          visibleRoles: _selectedRoles.toList(),
          isTemplate: _isTemplate,
          bannerEnabled: _bannerEnabled,
          bannerShowAt: showAt,
          bannerHideAt: hideAt,
          pushIntervalMinutes: interval,
          clearBannerShowAt: _bannerShowImmediately,
          clearBannerHideAt: _bannerHideManual,
          clearPushInterval: interval == null,
        );
      } else {
        await ctrl.createAnnouncement(
          title: _titleCtrl.text.trim(),
          body: _bodyCtrl.text.trim(),
          visibleRoles: _selectedRoles.toList(),
          isTemplate: _isTemplate,
          templateId: _selectedTemplateId,
          bannerEnabled: _bannerEnabled,
          bannerShowAt: showAt,
          bannerHideAt: hideAt,
          pushIntervalMinutes: interval,
        );
      }
      if (mounted) Navigator.of(context).pop();
      showSuccessSnackBarGlobal(
          widget.editing != null ? 'Announcement updated.' : 'Announcement posted.');
    } on AnnouncementNotificationException {
      if (mounted) {
        final messenger = ScaffoldMessenger.of(context);
        Navigator.of(context).pop();
        messenger.showSnackBar(
          const SnackBar(
            content: Text('Posted, but some notifications failed to send.'),
          ),
        );
      }
    } catch (e) {
      if (mounted) showErrorSnackBar(context, 'Failed to save: $e');
    } finally {
      if (mounted) setState(() => _submitting = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;
    final isEditing = widget.editing != null;

    final templates = ref
            .watch(announcementsProvider)
            .valueOrNull
            ?.where((a) => a.isTemplate)
            .toList() ??
        [];

    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Text(
            isEditing ? 'Edit Announcement' : 'New Announcement',
            style: tt.titleLarge?.copyWith(fontWeight: FontWeight.w600),
          ),
          const SizedBox(height: 20),

          // Template selector (only for new announcements)
          if (!isEditing && templates.isNotEmpty) ...[
            DropdownButtonFormField<String?>(
              decoration: InputDecoration(
                labelText: 'Post from template (optional)',
                border: const OutlineInputBorder(),
                suffixIcon: _selectedTemplateId != null
                    ? IconButton(
                        icon: const Icon(Icons.clear),
                        tooltip: 'Clear template',
                        onPressed: _clearTemplate,
                      )
                    : null,
              ),
              key: ValueKey(_selectedTemplateId),
              initialValue: _selectedTemplateId,
              items: [
                const DropdownMenuItem<String?>(
                  value: null,
                  child: Text('No template'),
                ),
                ...templates.map(
                  (t) => DropdownMenuItem<String?>(
                    value: t.id,
                    child: Text(
                      t.title.isEmpty ? '(Untitled)' : t.title,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                ),
              ],
              onChanged: (id) {
                if (id == null) {
                  _clearTemplate();
                } else {
                  final tmpl = templates.firstWhere((t) => t.id == id);
                  _applyTemplate(tmpl);
                }
              },
            ),
            const SizedBox(height: 16),
          ],

          // Title field
          TextField(
            controller: _titleCtrl,
            decoration: const InputDecoration(
              labelText: 'Title',
              border: OutlineInputBorder(),
            ),
            textInputAction: TextInputAction.next,
            onChanged: (_) => setState(() {}),
          ),
          const SizedBox(height: 16),

          // Body field
          TextField(
            controller: _bodyCtrl,
            decoration: const InputDecoration(
              labelText: 'Body',
              border: OutlineInputBorder(),
              alignLabelWithHint: true,
            ),
            maxLines: 6,
            minLines: 3,
            onChanged: (_) => setState(() {}),
          ),
          const SizedBox(height: 16),

          // Role visibility
          Text('Visible to:', style: tt.labelLarge),
          const SizedBox(height: 8),
          Wrap(
            spacing: 8,
            runSpacing: 6,
            children: _allRoles.map((role) {
              final selected = _selectedRoles.contains(role);
              return FilterChip(
                label: Text(_roleLabels[role] ?? role),
                selected: selected,
                onSelected: (val) {
                  setState(() {
                    if (val) {
                      _selectedRoles.add(role);
                    } else {
                      _selectedRoles.remove(role);
                    }
                  });
                },
              );
            }).toList(),
          ),
          const SizedBox(height: 16),

          // Template toggle
          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            title: Text('Save as template', style: tt.bodyMedium),
            subtitle: Text(
              'Templates can be selected when creating new announcements.',
              style: tt.bodySmall?.copyWith(color: cs.onSurfaceVariant),
            ),
            value: _isTemplate,
            onChanged: (val) => setState(() => _isTemplate = val),
          ),

          // ── Banner notification section ─────────────────────────────────
          const Divider(height: 24),
          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            title: Row(
              children: [
                Icon(Icons.campaign_outlined, size: 18, color: cs.primary),
                const SizedBox(width: 6),
                Text('Banner Notification', style: tt.bodyMedium),
              ],
            ),
            subtitle: Text(
              'Pin a prominent banner at the top of the Announcements screen.',
              style: tt.bodySmall?.copyWith(color: cs.onSurfaceVariant),
            ),
            value: _bannerEnabled,
            onChanged: (val) => setState(() => _bannerEnabled = val),
          ),

          if (_bannerEnabled) ...[
            const SizedBox(height: 12),
            _BannerOptionsPanel(
              showImmediately: _bannerShowImmediately,
              showAt: _bannerShowAt,
              hideManual: _bannerHideManual,
              hideAt: _bannerHideAt,
              pushIntervalMinutes: _pushIntervalMinutes,
              onShowImmediatelyChanged: (v) =>
                  setState(() => _bannerShowImmediately = v),
              onPickShowAt: _pickShowAt,
              onHideManualChanged: (v) =>
                  setState(() => _bannerHideManual = v),
              onPickHideAt: _pickHideAt,
              onIntervalChanged: (v) =>
                  setState(() => _pushIntervalMinutes = v),
            ),
          ],

          const SizedBox(height: 20),

          // Action buttons
          Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: [
              TextButton(
                onPressed: () => Navigator.of(context).pop(),
                child: const Text('Cancel'),
              ),
              const SizedBox(width: 12),
              FilledButton(
                onPressed: _canSubmit ? _submit : null,
                child: _submitting
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child: CircularProgressIndicator(
                            strokeWidth: 2, color: Colors.white),
                      )
                    : Text(isEditing ? 'Save' : 'Post'),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

// ─────────────────────────────────────────────────────────────────────────────
// Banner Settings dialog (post-creation editing)
// ─────────────────────────────────────────────────────────────────────────────

class _BannerSettingsContent extends ConsumerStatefulWidget {
  const _BannerSettingsContent({required this.announcement});

  final Announcement announcement;

  @override
  ConsumerState<_BannerSettingsContent> createState() =>
      _BannerSettingsContentState();
}

class _BannerSettingsContentState
    extends ConsumerState<_BannerSettingsContent> {
  late bool _bannerEnabled;
  late bool _bannerShowImmediately;
  DateTime? _bannerShowAt;
  late bool _bannerHideManual;
  DateTime? _bannerHideAt;
  int? _pushIntervalMinutes;
  bool _submitting = false;

  @override
  void initState() {
    super.initState();
    final a = widget.announcement;
    _bannerEnabled = a.bannerEnabled;
    _bannerShowAt = a.bannerShowAt;
    _bannerShowImmediately = a.bannerShowAt == null;
    _bannerHideAt = a.bannerHideAt;
    _bannerHideManual = a.bannerHideAt == null;
    _pushIntervalMinutes = a.pushIntervalMinutes;
  }

  Future<void> _pickShowAt() async {
    final dt = await pickDateTime(context, initial: _bannerShowAt);
    if (dt != null) setState(() => _bannerShowAt = dt);
  }

  Future<void> _pickHideAt() async {
    final dt = await pickDateTime(context, initial: _bannerHideAt);
    if (dt != null) setState(() => _bannerHideAt = dt);
  }

  Future<void> _save() async {
    setState(() => _submitting = true);
    try {
      final showAt = !_bannerShowImmediately ? _bannerShowAt : null;
      final hideAt = !_bannerHideManual ? _bannerHideAt : null;
      final interval = _bannerEnabled ? _pushIntervalMinutes : null;

      await ref.read(announcementsControllerProvider).updateBannerSettings(
            id: widget.announcement.id,
            bannerEnabled: _bannerEnabled,
            bannerShowAt: showAt,
            bannerHideAt: hideAt,
            pushIntervalMinutes: interval,
          );
      if (mounted) Navigator.of(context).pop();
      showSuccessSnackBarGlobal('Banner settings saved.');
    } catch (e) {
      if (mounted) showErrorSnackBar(context, 'Failed to save: $e');
    } finally {
      if (mounted) setState(() => _submitting = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;

    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Row(
            children: [
              Icon(Icons.campaign_outlined, color: cs.primary),
              const SizedBox(width: 8),
              Text(
                'Banner Settings',
                style: tt.titleLarge?.copyWith(fontWeight: FontWeight.w600),
              ),
            ],
          ),
          const SizedBox(height: 4),
          Text(
            widget.announcement.title,
            style: tt.bodySmall?.copyWith(color: cs.onSurfaceVariant),
            maxLines: 2,
            overflow: TextOverflow.ellipsis,
          ),
          const SizedBox(height: 20),

          SwitchListTile(
            contentPadding: EdgeInsets.zero,
            title: Text('Banner enabled', style: tt.bodyMedium),
            value: _bannerEnabled,
            onChanged: (v) => setState(() => _bannerEnabled = v),
          ),

          if (_bannerEnabled) ...[
            const SizedBox(height: 12),
            _BannerOptionsPanel(
              showImmediately: _bannerShowImmediately,
              showAt: _bannerShowAt,
              hideManual: _bannerHideManual,
              hideAt: _bannerHideAt,
              pushIntervalMinutes: _pushIntervalMinutes,
              onShowImmediatelyChanged: (v) =>
                  setState(() => _bannerShowImmediately = v),
              onPickShowAt: _pickShowAt,
              onHideManualChanged: (v) =>
                  setState(() => _bannerHideManual = v),
              onPickHideAt: _pickHideAt,
              onIntervalChanged: (v) =>
                  setState(() => _pushIntervalMinutes = v),
            ),
          ],

          const SizedBox(height: 20),
          Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: [
              TextButton(
                onPressed: () => Navigator.of(context).pop(),
                child: const Text('Cancel'),
              ),
              const SizedBox(width: 12),
              FilledButton(
                onPressed: _submitting ? null : _save,
                child: _submitting
                    ? const SizedBox(
                        width: 20,
                        height: 20,
                        child: CircularProgressIndicator(
                            strokeWidth: 2, color: Colors.white),
                      )
                    : const Text('Save'),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

// ─────────────────────────────────────────────────────────────────────────────
// Shared banner options sub-panel (show from / stop showing / push interval)
// ─────────────────────────────────────────────────────────────────────────────

class _BannerOptionsPanel extends StatelessWidget {
  const _BannerOptionsPanel({
    required this.showImmediately,
    required this.showAt,
    required this.hideManual,
    required this.hideAt,
    required this.pushIntervalMinutes,
    required this.onShowImmediatelyChanged,
    required this.onPickShowAt,
    required this.onHideManualChanged,
    required this.onPickHideAt,
    required this.onIntervalChanged,
  });

  final bool showImmediately;
  final DateTime? showAt;
  final bool hideManual;
  final DateTime? hideAt;
  final int? pushIntervalMinutes;
  final ValueChanged<bool> onShowImmediatelyChanged;
  final VoidCallback onPickShowAt;
  final ValueChanged<bool> onHideManualChanged;
  final VoidCallback onPickHideAt;
  final ValueChanged<int?> onIntervalChanged;

  @override
  Widget build(BuildContext context) {
    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;

    return Container(
      decoration: BoxDecoration(
        color: cs.primaryContainer.withValues(alpha: 0.35),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: cs.primary.withValues(alpha: 0.25)),
      ),
      padding: const EdgeInsets.all(16),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          // ── Show from ────────────────────────────────────────────────────
          Text('Show banner from', style: tt.labelMedium?.copyWith(color: cs.primary)),
          const SizedBox(height: 8),
          SegmentedButton<bool>(
            segments: const [
              ButtonSegment(value: true, label: Text('Auto (now)')),
              ButtonSegment(value: false, label: Text('Custom')),
            ],
            selected: {showImmediately},
            onSelectionChanged: (s) => onShowImmediatelyChanged(s.first),
            style: SegmentedButton.styleFrom(
              visualDensity: VisualDensity.compact,
            ),
          ),
          if (!showImmediately) ...[
            const SizedBox(height: 8),
            OutlinedButton.icon(
              onPressed: onPickShowAt,
              icon: const Icon(Icons.calendar_today_outlined, size: 16),
              label: Text(
                showAt != null ? _formatDt(showAt!) : 'Pick date & time',
              ),
            ),
          ],
          const SizedBox(height: 16),

          // ── Stop showing ─────────────────────────────────────────────────
          Text('Stop showing', style: tt.labelMedium?.copyWith(color: cs.primary)),
          const SizedBox(height: 8),
          SegmentedButton<bool>(
            segments: const [
              ButtonSegment(value: true, label: Text('Manual (admin/poster)')),
              ButtonSegment(value: false, label: Text('Auto')),
            ],
            selected: {hideManual},
            onSelectionChanged: (s) => onHideManualChanged(s.first),
            style: SegmentedButton.styleFrom(
              visualDensity: VisualDensity.compact,
            ),
          ),
          if (!hideManual) ...[
            const SizedBox(height: 8),
            OutlinedButton.icon(
              onPressed: onPickHideAt,
              icon: const Icon(Icons.event_busy_outlined, size: 16),
              label: Text(
                hideAt != null ? _formatDt(hideAt!) : 'Pick end date & time',
              ),
            ),
          ],
          const SizedBox(height: 16),

          // ── Push notification interval ────────────────────────────────
          Text('Push reminders', style: tt.labelMedium?.copyWith(color: cs.primary)),
          const SizedBox(height: 8),
          DropdownButtonFormField<int?>(
            key: ValueKey(pushIntervalMinutes),
            decoration: const InputDecoration(
              border: OutlineInputBorder(),
              isDense: true,
              contentPadding: EdgeInsets.symmetric(horizontal: 12, vertical: 10),
            ),
            initialValue: pushIntervalMinutes,
            items: _pushIntervalOptions
                .map((opt) => DropdownMenuItem<int?>(
                      value: opt.$1,
                      child: Text(opt.$2),
                    ))
                .toList(),
            onChanged: (v) => onIntervalChanged(v),
          ),
          if (pushIntervalMinutes != null)
            Padding(
              padding: const EdgeInsets.only(top: 6),
              child: Text(
                'A push notification will be sent to all visible users at this interval while the banner is active.',
                style: tt.bodySmall?.copyWith(color: cs.onSurfaceVariant),
              ),
            ),
        ],
      ),
    );
  }
}