import 'dart:async';

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

import '../session/account_codec.dart';
import '../session/session_lifecycle.dart';
import '../session/session_manager.dart';
import '../state/app/modules/account/bloc/account_bloc.dart';
import '../state/app/modules/account/bloc/account_state.dart';
import '../utils/haptics.dart';
import 'app_progress_indicator.dart';
import 'async_action_button.dart';
import 'centered_leading.dart';
import 'confirm_dialog.dart';
import 'details_bottom_sheet.dart';
import 'user_avatar.dart';

/// Lists the signed-in accounts: tap one to switch, add another, or sign out
/// of an inactive one.
Future<void> showAccountSwitcherSheet(BuildContext context) {
  final accountBloc = context.read<AccountBloc>();
  return showDetailsBottomSheet(
    context,
    header: Builder(
      builder: (headerContext) => ListTile(
        title: const Text('Konten'),
        trailing: TextButton.icon(
          icon: const Icon(Icons.person_add_alt_outlined, size: 18),
          label: const Text('Hinzufügen'),
          onPressed: () {
            Navigator.pop(headerContext);
            unawaited(startAddAccount(accountBloc));
          },
        ),
      ),
    ),
    children: (sheetContext) => [
      ValueListenableBuilder<AccountIndex>(
        valueListenable: SessionManager().accounts,
        builder: (context, index, _) => Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            for (final account in index.accounts)
              _AccountTile(
                account: account,
                active: account.id == index.activeId,
                accountBloc: accountBloc,
              ),
          ],
        ),
      ),
    ],
  );
}

/// Opens the login for another account; the active one is parked meanwhile.
Future<void> startAddAccount(AccountBloc accountBloc) async {
  await SessionLifecycle.beginAddAccount();
  accountBloc.setStatus(AccountStatus.addingAccount);
}

/// Stacked next to the account name, which needs the width more.
/// Only the horizontal padding is trimmed; height stays at a full tap target.
final ButtonStyle compactAccountButtonStyle = TextButton.styleFrom(
  padding: const EdgeInsets.symmetric(horizontal: 8),
);

/// Below the sign-out button: adds an account, or opens the switcher once
/// there is more than one.
class AccountSwitchButton extends StatelessWidget {
  const AccountSwitchButton({super.key});

  @override
  Widget build(BuildContext context) => ValueListenableBuilder<AccountIndex>(
    valueListenable: SessionManager().accounts,
    builder: (context, index, _) => index.accounts.length > 1
        ? TextButton.icon(
            style: compactAccountButtonStyle,
            icon: const Icon(Icons.switch_account_outlined, size: 18),
            label: const Text('Wechseln'),
            onPressed: () => showAccountSwitcherSheet(context),
          )
        : TextButton.icon(
            style: compactAccountButtonStyle,
            icon: const Icon(Icons.person_add_alt_outlined, size: 18),
            label: const Text('Hinzufügen'),
            onPressed: () => startAddAccount(context.read<AccountBloc>()),
          ),
  );
}

class _AccountTile extends StatefulWidget {
  final AccountEntry account;
  final bool active;
  final AccountBloc accountBloc;

  const _AccountTile({
    required this.account,
    required this.active,
    required this.accountBloc,
  });

  @override
  State<_AccountTile> createState() => _AccountTileState();
}

class _AccountTileState extends State<_AccountTile> {
  bool _busy = false;

  Future<void> _switch() async {
    Haptics.selection();
    setState(() => _busy = true);
    final ok = await runWithErrorDialog(
      context,
      () => SessionLifecycle.switchTo(widget.account.id),
    );
    if (!mounted) return;
    setState(() => _busy = false);
    if (!ok) return;
    Navigator.pop(context);
    widget.accountBloc.activated(SessionManager().activeAccount?.id);
  }

  void _confirmRemove() => ConfirmDialog(
    title: 'Abmelden?',
    content:
        '${widget.account.displayName ?? widget.account.label} wird von diesem Gerät abgemeldet und seine '
        'lokal gespeicherten Daten werden gelöscht.',
    confirmButton: 'Abmelden',
    onConfirmAsync: () => SessionLifecycle.removeInactive(widget.account.id),
  ).asDialog(context);

  @override
  Widget build(BuildContext context) {
    final account = widget.account;
    return ListTile(
      leading: CenteredLeading(
        _busy
            ? const SizedBox.square(
                dimension: 24,
                child: AppProgressIndicator.small(),
              )
            : _AccountAvatar(account: account),
      ),
      title: Text(
        account.displayName ?? account.label,
        maxLines: 1,
        overflow: TextOverflow.ellipsis,
      ),
      subtitle: Text(
        account.isDemo ? '${account.label} (Demo)' : account.label,
        maxLines: 1,
        overflow: TextOverflow.ellipsis,
      ),
      // Sized like the IconButton so both line up.
      trailing: widget.active
          ? const SizedBox.square(
              dimension: kMinInteractiveDimension,
              child: Icon(Icons.check),
            )
          : IconButton(
              icon: const Icon(Icons.logout_outlined),
              tooltip: 'Abmelden',
              onPressed: _busy ? null : _confirmRemove,
            ),
      onTap: widget.active || _busy ? null : _switch,
    );
  }
}

class _AccountAvatar extends StatelessWidget {
  final AccountEntry account;

  const _AccountAvatar({required this.account});

  @override
  Widget build(BuildContext context) {
    // Demo accounts have no real Nextcloud user behind them.
    if (!account.isGuardian && !account.isDemo) {
      return UserAvatar(id: account.label, size: 16);
    }
    final colors = Theme.of(context).colorScheme;
    return CircleAvatar(
      radius: 16,
      backgroundColor: colors.secondaryContainer,
      foregroundColor: colors.onSecondaryContainer,
      child: account.isGuardian
          ? const Icon(Icons.family_restroom_outlined, size: 18)
          : Text(account.label.characters.first.toUpperCase()),
    );
  }
}