// Version: 1.1.0 | Created: 2026-04-11 | Updated: 2026-04-11
// Help tab with in-app guidance for common tasks and troubleshooting.

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

import '../../../core/network/matrix_client.dart';
import '../../profile/presentation/security_setup_dialog.dart';

void _launchUrl(BuildContext context, String url) {
  web.window.open(url, '_blank');
}

class HelpTab extends ConsumerWidget {
  const HelpTab({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final theme = Theme.of(context);
    final client = ref.watch(matrixClientProvider);

    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        Padding(
          padding: const EdgeInsets.only(bottom: 16),
          child: Text(
            'Help & Troubleshooting',
            style: theme.textTheme.headlineSmall?.copyWith(
              fontWeight: FontWeight.bold,
            ),
          ),
        ),

        // --- Encrypted messages ---
        _HelpCard(
          icon: Icons.lock_outline,
          title: 'I see "Encrypted — use Element to read"',
          children: [
            const _HelpParagraph(
              'This means your device does not have the keys needed to '
              'read those messages. This happens when:',
            ),
            const _HelpBullet(
                'You are using M8Chat on a new device or browser.'),
            const _HelpBullet(
                'The messages were sent before you set up security.'),
            const _HelpBullet(
                'Your browser data was cleared.'),
            const SizedBox(height: 12),
            const _HelpSubheading('How to fix it'),
            const _HelpParagraph(
              '1. Go to the Profile tab.\n'
              '2. Tap Security & Privacy to expand it.\n'
              '3. Tap Security setup.\n'
              '4. If you have set up security before, enter your '
              'recovery key. If not, a new one will be created for you.\n'
              '5. Save the recovery key somewhere safe.\n'
              '6. After setup, go back to your rooms. Messages should '
              'now be readable.',
            ),
            const SizedBox(height: 12),
            const _HelpSubheading('What is a recovery key?'),
            const _HelpParagraph(
              'A recovery key is a long code starting with "EsTc" that '
              'unlocks your encrypted messages. It was shown to you when '
              'you first set up security in Element or M8Chat. If you '
              'saved it, you can use it to restore your messages on any '
              'device.',
            ),
            const SizedBox(height: 12),
            Builder(
              builder: (context) => OutlinedButton.icon(
                onPressed: () =>
                    showSecuritySetupDialog(context, client),
                icon: const Icon(Icons.shield_outlined),
                label: const Text('Open Security Setup'),
              ),
            ),
          ],
        ),

        // --- New to M8Chat ---
        const _HelpCard(
          icon: Icons.chat_bubble_outline,
          title: 'Getting started with M8Chat',
          children: [
            _HelpParagraph(
              'M8Chat is a secure messaging app built on the Matrix '
              'protocol. All your messages are end-to-end encrypted, '
              'meaning only you and the people you chat with can read '
              'them.',
            ),
            SizedBox(height: 12),
            _HelpSubheading('First steps'),
            _HelpParagraph(
              '1. Set up security: go to Profile > Security & Privacy '
              '> Security setup. This creates your encryption keys and '
              'backs them up.\n'
              '2. Save your recovery key — you will need it if you ever '
              'log in on a new device.\n'
              '3. Start chatting. Tap the pencil icon at the top right '
              'to search for users and start a conversation.',
            ),
          ],
        ),

        // --- Joining a conference ---
        const _HelpCard(
          icon: Icons.videocam_outlined,
          title: 'Joining a video conference',
          children: [
            _HelpParagraph(
              'M8Chat supports Jitsi video conferences. To join one:',
            ),
            SizedBox(height: 8),
            _HelpParagraph(
              '1. Tap the Conference tab at the bottom.\n'
              '2. Paste the meeting link (e.g. conf.m8chat.au/MyMeeting).\n'
              '3. Tap Join Meeting.\n\n'
              'You can also make voice and video calls directly from any '
              'chat room using the phone and camera icons at the top of '
              'the conversation.',
            ),
          ],
        ),

        // --- Video call issues ---
        const _HelpCard(
          icon: Icons.videocam_off_outlined,
          title: 'Video call problems',
          children: [
            _HelpSubheading('Scrambled or black video'),
            _HelpParagraph(
              'If video appears scrambled when calling someone on Element X, '
              'this is an encryption compatibility issue that is being '
              'worked on. Try calling from the same app on both ends.',
            ),
            SizedBox(height: 8),
            _HelpSubheading('No audio or robotic sound'),
            _HelpParagraph(
              'This is usually caused by browser permissions. Make sure '
              'you have allowed microphone and camera access when '
              'prompted. On some devices (especially Sailfish OS), the '
              'audio codec support may be limited.',
            ),
          ],
        ),

        // --- Account & privacy ---
        const _HelpCard(
          icon: Icons.security_outlined,
          title: 'Account & privacy',
          children: [
            _HelpSubheading('Who can read my messages?'),
            _HelpParagraph(
              'Only you and the people in the conversation. M8Chat uses '
              'end-to-end encryption — not even the server operator can '
              'read your messages.',
            ),
            SizedBox(height: 8),
            _HelpSubheading('Can I use multiple devices?'),
            _HelpParagraph(
              'Yes. Set up security on each device using the same '
              'recovery key. Your messages will be available on all '
              'devices where security is set up.',
            ),
            SizedBox(height: 8),
            _HelpSubheading('What happens if I lose my recovery key?'),
            _HelpParagraph(
              'You will not be able to read old messages on new devices. '
              'New messages will still work. You can create a new '
              'recovery key from the Security setup, but old messages '
              'encrypted with the previous key will remain unreadable.',
            ),
          ],
        ),

        // --- Account management ---
        _HelpCard(
          icon: Icons.manage_accounts_outlined,
          title: 'Account management',
          children: [
            const _HelpParagraph(
              'All account changes need to be made through the M8Chat '
              'website. This includes:',
            ),
            const _HelpBullet('Changing your password'),
            const _HelpBullet('Membership settings and billing'),
            const _HelpBullet('Updating your profile or email'),
            const _HelpBullet('Deleting your account'),
            const SizedBox(height: 12),
            Builder(
              builder: (context) => OutlinedButton.icon(
                onPressed: () => _launchUrl(context, 'https://m8chat.au'),
                icon: const Icon(Icons.open_in_new),
                label: const Text('Go to m8chat.au'),
              ),
            ),
            const SizedBox(height: 12),
            const _HelpSubheading('Privacy'),
            const _HelpParagraph(
              'No account details or other privacy or user identifiers '
              'are saved or stored on this application. All data stays '
              'on the M8Chat server and is protected by end-to-end '
              'encryption.',
            ),
            const SizedBox(height: 12),
            const _HelpParagraph(
              'For more information about what happens if things go '
              'wrong, including data recovery and account issues:',
            ),
            const SizedBox(height: 8),
            Builder(
              builder: (context) => OutlinedButton.icon(
                onPressed: () => _launchUrl(
                    context, 'https://m8chat.au/when-it-all-goes-wrong/'),
                icon: const Icon(Icons.open_in_new),
                label: const Text('When it all goes wrong'),
              ),
            ),
          ],
        ),

        const SizedBox(height: 32),
        Center(
          child: Text(
            'Need more help? Visit m8chat.au or contact the M8Chat team.',
            style: theme.textTheme.bodySmall?.copyWith(
              color: theme.colorScheme.onSurface.withAlpha(102),
            ),
          ),
        ),
        const SizedBox(height: 16),
      ],
    );
  }
}

// --- Reusable help widgets ---

class _HelpCard extends StatelessWidget {
  const _HelpCard({
    required this.icon,
    required this.title,
    required this.children,
  });

  final IconData icon;
  final String title;
  final List<Widget> children;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      child: ExpansionTile(
        leading: Icon(icon, color: theme.colorScheme.primary),
        title: Text(
          title,
          style: theme.textTheme.titleSmall?.copyWith(
            fontWeight: FontWeight.w600,
          ),
        ),
        childrenPadding:
            const EdgeInsets.symmetric(horizontal: 20, vertical: 12),
        expandedCrossAxisAlignment: CrossAxisAlignment.start,
        children: children,
      ),
    );
  }
}

class _HelpParagraph extends StatelessWidget {
  const _HelpParagraph(this.text);
  final String text;

  @override
  Widget build(BuildContext context) {
    return Text(
      text,
      style: Theme.of(context).textTheme.bodyMedium?.copyWith(height: 1.5),
    );
  }
}

class _HelpSubheading extends StatelessWidget {
  const _HelpSubheading(this.text);
  final String text;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 4),
      child: Text(
        text,
        style: Theme.of(context).textTheme.titleSmall?.copyWith(
              fontWeight: FontWeight.w600,
            ),
      ),
    );
  }
}

class _HelpBullet extends StatelessWidget {
  const _HelpBullet(this.text);
  final String text;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(left: 8, top: 4),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('\u2022  '),
          Expanded(
            child: Text(
              text,
              style: Theme.of(context)
                  .textTheme
                  .bodyMedium
                  ?.copyWith(height: 1.5),
            ),
          ),
        ],
      ),
    );
  }
}