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

import '../services/app_state.dart';

/// The very first thing shown on a fresh install — before the onboarding
/// tour, before anything else — gating [MainShell] entirely until the user
/// taps "I Agree" (see [AppRoot] in main.dart and
/// [AppState.hasAcceptedUserAgreement]/[AppState.acceptUserAgreement]).
/// Its whole purpose is the liability section below: this app stores data
/// on the user's own device (and, optionally, their own cloud storage
/// account) with no server or backend of ours involved, so we have no
/// ability to recover anything for them if it's lost.
class UserAgreementScreen extends StatelessWidget {
  const UserAgreementScreen({super.key});

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

    return Scaffold(
      appBar: AppBar(title: const Text('User Agreement'), automaticallyImplyLeading: false),
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: ListView(
                padding: const EdgeInsets.all(20),
                children: [
                  Text(
                    'Please read and accept the following before using Show Me The Fuel '
                    'Refund.',
                    style: textTheme.bodyLarge,
                  ),
                  const SizedBox(height: 20),
                  _Section(
                    title: 'Your Data Lives on Your Device',
                    body:
                        'Every vehicle, fuel receipt, and photo you log is stored locally on '
                        'this device. If you connect a cloud storage account (Google Drive, '
                        'Dropbox, OneDrive, or your own WebDAV server) in Settings, a copy is '
                        'also kept there — in storage you control, not on any server we run. '
                        "We don't operate a backend, and we don't have a copy of your data.",
                  ),
                  _Section(
                    title: 'We Are Not Responsible for Your Data or Any Data Loss',
                    body:
                        'The developer is not responsible for your data, or for any loss, '
                        'corruption, or unavailability of it, for any reason — including but '
                        'not limited to device loss, theft, or damage; an uninstall or app/OS '
                        'update; a bug in this app; or an outage or account issue with a cloud '
                        'storage provider you connect. Backing up your data (by connecting a '
                        'cloud storage account, and by keeping it connected and in good '
                        'standing) is entirely your responsibility. If you never connect a '
                        'backup, the only copy of your data is the one on this device.',
                  ),
                  _Section(
                    title: 'Provided As-Is',
                    body:
                        'This app is provided "as is," without warranty of any kind, express or '
                        'implied. Fuel and gallon values are read automatically from your '
                        'receipt photos and may be misread — always review them before relying '
                        'on them, including for a refund claim.',
                  ),
                  _Section(
                    title: 'Not Tax or Legal Advice',
                    body:
                        "This app helps you organize receipts for Missouri's Motor Fuel Tax "
                        'Refund program; it does not provide tax or legal advice, and does not '
                        'guarantee your eligibility for any refund. The program itself is set '
                        'by Missouri law, which can change at any time — always confirm current '
                        'eligibility and rates with the Missouri Department of Revenue.',
                  ),
                  const SizedBox(height: 8),
                ],
              ),
            ),
            const Divider(height: 1),
            Padding(
              padding: const EdgeInsets.all(16),
              child: Row(
                children: [
                  Expanded(
                    child: OutlinedButton(
                      onPressed: () => SystemNavigator.pop(),
                      child: const Text('Decline'),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: FilledButton(
                      onPressed: () => context.read<AppState>().acceptUserAgreement(),
                      child: const Text('I Agree'),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _Section extends StatelessWidget {
  final String title;
  final String body;

  const _Section({required this.title, required this.body});

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Padding(
      padding: const EdgeInsets.only(bottom: 20),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(title, style: textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w700)),
          const SizedBox(height: 6),
          Text(body, style: textTheme.bodyMedium),
        ],
      ),
    );
  }
}