import 'dart:developer';

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:halkyon_app/l10n/halkyon_app_localizations.dart';
import 'package:halkyon_app/src/app/app_scope.dart';
import 'package:halkyon_app/src/auth/bloc/session_bloc.dart';
import 'package:halkyon_app/src/instance/instance_scope.dart';
import 'package:halkyon_app/src/instance/widget/account_switcher_sheet.dart';
import 'package:halkyon_app/src/password/model/account_security.dart';
import 'package:halkyon_app/src/password/model/password_failed.dart';
import 'package:halkyon_app/src/password/widget/delete_account_sheet.dart';
import 'package:halkyon_ui/halkyon_ui.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';
import 'package:material_ui/material_ui.dart';

/// The account in use, as an app's settings show it (decided 2026-10-16):
/// whose it is, anonymous or signed in, on which instance; switching to the
/// account on another instance, where the device keeps accounts on several
/// ([InstanceScope]); signing out, which of an anonymous account deletes it
/// and so asks first; deleting it, after asking. What only the app can say,
/// it gives: what an anonymous account keeps on the device, and what signing
/// out of one and deleting the account take with them.
class const AccountTiles({
  /// Under an anonymous account: what it keeps on this device ("Progress is
  /// saved on this device. Sign in to keep it."); none where null.
  final String? anonymousNote,

  /// What signing out of an anonymous account takes with it, as the
  /// question before asks.
  required final String signOutAnonymousMessage,

  /// What deleting the account takes with it, as the question before asks.
  required final String deleteMessage,
  super.key,
}) extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final l10n = HalkyonAppLocalizations.of(context);
    final theme = Theme.of(context);
    final identified = switch (context.watch<SessionBloc>().state) {
      SessionStateActive(:final person) => person.isIdentified,
      _ => false,
    };
    final instances = InstanceScope.maybeOf(context);
    final instance =
        instances?.choice.current?.name ??
        AppScope.of<AppDependencies<Disposable>>(context).serverName;
    return Column(
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        ListTile(
          leading: Icon(
            identified ? LucideIcons.userCheck : LucideIcons.userRound,
          ),
          title: Text(
            identified
                ? l10n.accountSignedInOn(instance)
                : l10n.accountAnonymousOn(instance),
          ),
          subtitle: switch (anonymousNote) {
            final note? when !identified => Text(note),
            _ => null,
          },
        ),
        // The accounts on this device, one per instance.
        if (instances != null)
          ListTile(
            leading: const Icon(LucideIcons.users),
            title: Text(l10n.accountSwitch),
            subtitle: Text(instances.choice.current?.name ?? ''),
            onTap: () => showAccountSwitcher(context),
          ),
        ListTile(
          leading: const Icon(LucideIcons.logOut),
          title: Text(l10n.accountSignOut),
          onTap: () => _signOut(context),
        ),
        ListTile(
          leading: Icon(LucideIcons.trash2, color: theme.colorScheme.error),
          title: Text(
            l10n.accountDelete,
            style: TextStyle(color: theme.colorScheme.error),
          ),
          onTap: () => _delete(context),
        ),
      ],
    );
  }

  /// Signs out; an anonymous account can't be signed into again, so signing
  /// out of one deletes it, and asks first. The app then asks how to start.
  Future<void> _signOut(BuildContext context) async {
    final l10n = HalkyonAppLocalizations.of(context);
    final session = context.read<SessionBloc>();
    final identified = switch (session.state) {
      SessionStateActive(:final person) => person.isIdentified,
      _ => false,
    };
    if (!identified &&
        !await confirmDestructiveAction(
          context,
          title: l10n.accountSignOutTitle,
          message: signOutAnonymousMessage,
          confirmLabel: l10n.accountSignOut,
        )) {
      return;
    }
    session.add(const SessionEventSignOutRequested());
  }

  /// Deletes the account with everything in it, after asking; an account
  /// with a password only with it and a code (ADR 0017), which a sheet asks
  /// for.
  Future<void> _delete(BuildContext context) async {
    final l10n = HalkyonAppLocalizations.of(context);
    final session = context.read<SessionBloc>();
    final passwords = AppScope.of(context).passwords;
    final identified = switch (session.state) {
      SessionStateActive(:final person) => person.isIdentified,
      _ => false,
    };
    if (!await confirmDestructiveAction(
      context,
      title: l10n.accountDeleteTitle,
      message: deleteMessage,
      confirmLabel: l10n.accountDelete,
    )) {
      return;
    }
    final AccountSecurity? security;
    try {
      security = identified ? await passwords.security() : null;
    } on Object catch (error) {
      if (error is PasswordFailed && error.problem != PasswordProblem.failed) {
        // The instance refused to say (no passwords offered there): the
        // session's own deletion, which the instance checks.
        session.add(const SessionEventDeleteRequested());
        return;
      }
      // Out of reach, or anything else: said so, nothing deleted (the short
      // reading: a deletion by the session alone, refused for an account
      // with a password, showed a spinner, then nothing).
      if (error is! PasswordFailed) {
        log('Reading the account failed: ${error.runtimeType}', name: 'Auth');
      }
      if (context.mounted) {
        ScaffoldMessenger.maybeOf(
          context,
        )?.showSnackBar(SnackBar(content: Text(l10n.passwordFailed)));
      }
      return;
    }
    if (security == null || !security.hasPassword) {
      session.add(const SessionEventDeleteRequested());
    } else if (context.mounted) {
      // Without a second factor that works, a code by mail confirms it.
      await showDeleteAccountWithPassword(
        context,
        byMail: !security.secondFactorWorks,
      );
    }
  }
}