/// 成员管理页（UI-03 §4 页面 11 重设计）：Owner 单独分组（无移除）+
/// Collaborators 列表（首字母头像、显示名、账号·角色、行尾「⋯」移除）；
/// 底部全宽「Invite colleague」打开账号前缀搜索 BottomSheet（300ms 防抖、
/// ≥2 字符、迟到响应守卫、已成员「Already added」态、MEMBER_CONFLICT
/// 本地化）。移除经确认对话框（含成员名）。本人/创建者不可移除；成员
/// 分页保留。
library;

import 'dart:async';

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

import '../core/api_client.dart';
import '../core/app_exception.dart';
import '../core/error_codes.dart';
import '../core/error_l10n.dart';
import '../features/albums/models.dart';
import '../l10n/app_localizations.dart';
import '../ui/components/section_header.dart';
import '../ui/tokens.dart';

/// 成员管理（从详情页携带完整 [album] 进入）。
class AlbumMembersPage extends ConsumerStatefulWidget {
  const AlbumMembersPage({required this.album, super.key});

  final Album album;

  @override
  ConsumerState<AlbumMembersPage> createState() => _AlbumMembersPageState();
}

class _AlbumMembersPageState extends ConsumerState<AlbumMembersPage> {
  static const int _pageSize = 50;

  List<Member> _items = const <Member>[];
  String? _nextCursor;
  bool _hasMore = false;
  bool _loading = true;
  bool _loadingMore = false;
  String? _errorCode;

  /// 当前登录账号（本人移除 UI 拦截用）；读取失败按未知处理。
  String? _selfAccount;

  @override
  void initState() {
    super.initState();
    _loadSelfAccount();
    _reload();
  }

  Future<void> _loadSelfAccount() async {
    try {
      final session = await ref.read(sessionStoreProvider).read();
      if (mounted) {
        setState(() => _selfAccount = session?.account);
      }
    } on Object {
      // 存储读取失败不阻断页面（移除按钮保护回退服务端 403/409 裁决）。
    }
  }

  Future<void> _reload() async {
    setState(() {
      _loading = true;
      _errorCode = null;
    });
    try {
      final page = await ref
          .read(apiClientProvider)
          .listMembers(widget.album.id, limit: _pageSize);
      if (mounted) {
        setState(() {
          _items = page.items;
          _nextCursor = page.nextCursor;
          _hasMore = page.hasMore;
          _loading = false;
        });
      }
    } on AppException catch (e) {
      if (mounted) {
        setState(() {
          _errorCode = e.code;
          _loading = false;
        });
      }
    } on Object {
      if (mounted) {
        setState(() {
          _errorCode = ErrorCodes.internalError;
          _loading = false;
        });
      }
    }
  }

  Future<void> _loadMore() async {
    if (_loading || _loadingMore || !_hasMore) return;
    setState(() => _loadingMore = true);
    try {
      final page = await ref.read(apiClientProvider).listMembers(
            widget.album.id,
            cursor: _nextCursor,
            limit: _pageSize,
          );
      if (mounted) {
        setState(() {
          _items = <Member>[..._items, ...page.items];
          _nextCursor = page.nextCursor;
          _hasMore = page.hasMore;
          _loadingMore = false;
        });
      }
    } on AppException catch (e) {
      if (mounted) {
        setState(() => _loadingMore = false);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(AppLocalizations.of(context).messageForError(e))),
        );
      }
    } on Object {
      if (mounted) {
        setState(() => _loadingMore = false);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(AppLocalizations.of(context).errorGeneric),
          ),
        );
      }
    }
  }

  // ── 邀请（BottomSheet 搜索选择器） ─────────────────────────────

  Future<void> _openInviteSheet() async {
    await showModalBottomSheet<void>(
      context: context,
      showDragHandle: true,
      isScrollControlled: true,
      useSafeArea: true,
      builder: (_) => AlbumInviteSheet(
        albumId: widget.album.id,
        // 打开时的既有成员（已添加态判定；面板内邀请成功后本地累加）。
        memberUserIds: <String>{
          for (final m in _items) m.userId,
        },
        memberAccounts: <String>{
          for (final m in _items) m.account,
        },
        onInvited: _reload,
      ),
    );
  }

  // ── 移除（行尾「⋯」→ 确认对话框） ─────────────────────────────

  Future<void> _remove(Member member) async {
    final l10n = AppLocalizations.of(context);
    final name = member.displayName.trim().isNotEmpty
        ? member.displayName.trim()
        : member.account;
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (_) => AlertDialog(
        title: Text(l10n.removeMember),
        content: Text(l10n.removeMemberConfirm(name)),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: Text(l10n.cancel),
          ),
          FilledButton(
            onPressed: () => Navigator.of(context).pop(true),
            child: Text(l10n.delete),
          ),
        ],
      ),
    );
    if (confirmed != true || !mounted) return;
    final messenger = ScaffoldMessenger.of(context);
    try {
      await ref
          .read(apiClientProvider)
          .removeMember(widget.album.id, member.userId);
      await _reload();
    } on AppException catch (e) {
      messenger.showSnackBar(
        SnackBar(content: Text(l10n.messageForError(e))),
      );
    } on Object {
      messenger.showSnackBar(
        SnackBar(content: Text(l10n.errorGeneric)),
      );
    }
  }

  bool _canRemove(Member member) =>
      member.role != MemberRole.owner && member.account != _selfAccount;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final owners = _items.where((m) => m.role == MemberRole.owner).toList();
    final collaborators =
        _items.where((m) => m.role != MemberRole.owner).toList();
    return Scaffold(
      appBar: AppBar(
        title: Text(
          _loading ? l10n.membersTitle : l10n.membersTitleCount(_items.length),
        ),
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : _errorCode != null
              ? _ErrorRetryView(
                  message: l10n.messageForErrorCode(_errorCode!),
                  onRetry: _reload,
                )
              : _memberGroups(l10n, owners, collaborators),
      // 全宽「Invite colleague」：避让安全区，键盘/列表常驻可达。
      bottomNavigationBar: SafeArea(
        minimum: const EdgeInsets.fromLTRB(kSpace16, kSpace8, kSpace16, kSpace12),
        child: FilledButton.icon(
          onPressed: _loading ? null : _openInviteSheet,
          icon: const Icon(Icons.person_add_outlined),
          label: Text(l10n.inviteColleague),
        ),
      ),
    );
  }

  /// Owner 单独组 + Collaborators 组；滚动加载更多挂在列表底部。
  Widget _memberGroups(
    AppLocalizations l10n,
    List<Member> owners,
    List<Member> collaborators,
  ) {
    final theme = Theme.of(context);
    return ListView(
      padding: const EdgeInsets.fromLTRB(kSpace16, kSpace16, kSpace16, kSpace24),
      children: [
        SectionHeader(title: l10n.ownerGroup),
        const SizedBox(height: kSpace8),
        Card(
          margin: EdgeInsets.zero,
          clipBehavior: Clip.antiAlias,
          child: Column(
            children: [
              for (final (i, member) in owners.indexed) ...[
                if (i > 0) const Divider(height: 1, indent: kSpace16, endIndent: kSpace16),
                _MemberRow(
                  member: member,
                  isSelf: member.account == _selfAccount,
                  onRemove: null, // 创建者不可移除（无「⋯」）
                ),
              ],
            ],
          ),
        ),
        const SizedBox(height: kSpace24),
        SectionHeader(title: l10n.collaboratorsGroup),
        const SizedBox(height: kSpace8),
        if (collaborators.isEmpty)
          Padding(
            padding: const EdgeInsets.symmetric(vertical: kSpace12),
            child: Text(
              l10n.noCollaborators,
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
          )
        else
          Card(
            margin: EdgeInsets.zero,
            clipBehavior: Clip.antiAlias,
            child: Column(
              children: [
                for (final (i, member) in collaborators.indexed) ...[
                  if (i > 0) const Divider(height: 1, indent: kSpace16, endIndent: kSpace16),
                  _MemberRow(
                    member: member,
                    isSelf: member.account == _selfAccount,
                    onRemove: _canRemove(member) ? () => _remove(member) : null,
                  ),
                ],
              ],
            ),
          ),
        if (_hasMore || _loadingMore)
          Padding(
            padding: const EdgeInsets.symmetric(vertical: kSpace16),
            child: Center(
              child: _loadingMore
                  ? const SizedBox(
                      height: 24,
                      width: 24,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : // 滚到底部自动取下一页（沿用旧列表的触发时机）。
                    _LoadMoreTrigger(onTriggered: _loadMore),
            ),
          ),
      ],
    );
  }
}

/// 成员行：首字母头像 + 显示名（本人标记）+ 账号·角色 + 行尾「⋯」（仅可
/// 移除成员显示；点击直接进入移除确认）。
class _MemberRow extends StatelessWidget {
  const _MemberRow({
    required this.member,
    required this.isSelf,
    this.onRemove,
  });

  final Member member;
  final bool isSelf;

  /// 移除回调；null = 不显示「⋯」（创建者/本人）。
  final VoidCallback? onRemove;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final name = member.displayName.trim().isNotEmpty
        ? member.displayName.trim()
        : member.account;
    final role = member.role == MemberRole.owner
        ? l10n.roleOwner
        : l10n.roleCollaborator;
    return ListTile(
      leading: CircleAvatar(child: Text(name.substring(0, 1).toUpperCase())),
      title: Text(isSelf ? '$name${l10n.selfMarker}' : name),
      subtitle: Text('${member.account} · $role'),
      trailing: onRemove == null
          ? null
          : IconButton(
              tooltip: l10n.removeMember,
              icon: const Icon(Icons.more_horiz),
              onPressed: onRemove,
            ),
    );
  }
}

/// 「加载更多」触发器：布局进列表尾部即触发一次下一页请求。
class _LoadMoreTrigger extends StatelessWidget {
  const _LoadMoreTrigger({required this.onTriggered});

  final VoidCallback onTriggered;

  @override
  Widget build(BuildContext context) {
    WidgetsBinding.instance.addPostFrameCallback((_) => onTriggered());
    return const SizedBox(height: 24, width: 24);
  }
}

/// 邀请同事 BottomSheet：账号前缀搜索（防抖 300ms、≥2 字符）→ 结果行
/// （头像 + 显示名 + 账号 + Add）；已成员显示「Already added」不可再加。
/// 邀请成功提示 + 回调上级刷新列表；本地累加已添加集合保持面板状态。
class AlbumInviteSheet extends ConsumerStatefulWidget {
  const AlbumInviteSheet({
    required this.albumId,
    required this.memberUserIds,
    required this.memberAccounts,
    required this.onInvited,
    super.key,
  });

  final String albumId;

  /// 打开面板时的成员用户 ID 集合。
  final Set<String> memberUserIds;

  /// 打开面板时的成员账号集合（按账号兜底判重）。
  final Set<String> memberAccounts;

  /// 邀请成功回调（上级刷新成员列表）。
  final VoidCallback onInvited;

  @override
  ConsumerState<AlbumInviteSheet> createState() => _AlbumInviteSheetState();
}

class _AlbumInviteSheetState extends ConsumerState<AlbumInviteSheet> {
  final TextEditingController _searchController = TextEditingController();
  Timer? _debounce;
  bool _searching = false;
  List<AdminUserLookupItem>? _results;

  /// 面板生命周期内新增的成员（已添加态即时生效）。
  final Set<String> _addedIds = <String>{};

  @override
  void dispose() {
    _debounce?.cancel();
    _searchController.dispose();
    super.dispose();
  }

  bool _isMember(AdminUserLookupItem user) =>
      widget.memberUserIds.contains(user.id) ||
      _addedIds.contains(user.id) ||
      widget.memberAccounts.contains(user.account);

  void _onSearchChanged(String text) {
    _debounce?.cancel();
    final query = text.trim();
    if (query.length < 2) {
      setState(() {
        _searching = false;
        _results = null;
      });
      return;
    }
    _debounce = Timer(const Duration(milliseconds: 300), () {
      _runSearch(query);
    });
  }

  Future<void> _runSearch(String query) async {
    setState(() => _searching = true);
    try {
      final items = await ref
          .read(apiClientProvider)
          .lookupUsers(query, limit: 10);
      // 迟到响应守卫：仅当输入未再变化时应用结果。
      if (!mounted || query != _searchController.text.trim()) return;
      setState(() {
        _results = items;
        _searching = false;
      });
    } on AppException catch (e) {
      if (!mounted || query != _searchController.text.trim()) return;
      setState(() => _searching = false);
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(AppLocalizations.of(context).messageForError(e)),
        ),
      );
    } on Object {
      if (!mounted || query != _searchController.text.trim()) return;
      setState(() => _searching = false);
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(AppLocalizations.of(context).errorGeneric)),
      );
    }
  }

  Future<void> _invite(AdminUserLookupItem user) async {
    final l10n = AppLocalizations.of(context);
    final messenger = ScaffoldMessenger.of(context);
    try {
      await ref.read(apiClientProvider).addMember(widget.albumId, user.id);
      if (!mounted) return;
      _addedIds.add(user.id);
      setState(() {});
      messenger.showSnackBar(
        SnackBar(content: Text(l10n.memberInvited)),
      );
      widget.onInvited();
    } on AppException catch (e) {
      messenger.showSnackBar(
        SnackBar(
          content: Text(
            e.code == ErrorCodes.memberConflict
                ? l10n.errorMemberConflict
                : l10n.messageForError(e),
          ),
        ),
      );
    } on Object {
      messenger.showSnackBar(
        SnackBar(content: Text(l10n.errorGeneric)),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    return Padding(
      // 键盘避让：输入框跟随视口内边距上移。
      padding: EdgeInsets.fromLTRB(
        kSpace16,
        0,
        kSpace16,
        MediaQuery.of(context).viewInsets.bottom + kSpace16,
      ),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          TextField(
            controller: _searchController,
            autofocus: true,
            onChanged: _onSearchChanged,
            decoration: InputDecoration(
              prefixIcon: const Icon(Icons.person_search_outlined),
              hintText: l10n.inviteSearchHint,
              border: const OutlineInputBorder(),
              suffixIcon: _searching
                  ? const Padding(
                      padding: EdgeInsets.all(12),
                      child: SizedBox(
                        height: 18,
                        width: 18,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      ),
                    )
                  : (_searchController.text.isEmpty
                      ? null
                      : IconButton(
                          icon: const Icon(Icons.clear),
                          onPressed: () {
                            _searchController.clear();
                            _onSearchChanged('');
                          },
                        )),
            ),
          ),
          const SizedBox(height: kSpace8),
          if (_results != null) Flexible(child: _resultsList(l10n)),
        ],
      ),
    );
  }

  /// 结果列表（面板高度内滚动；无结果显示占位文案）。
  Widget _resultsList(AppLocalizations l10n) {
    final results = _results!;
    if (results.isEmpty) {
      return Padding(
        padding: const EdgeInsets.symmetric(vertical: kSpace12),
        child: Text(
          l10n.inviteNoResults,
          textAlign: TextAlign.center,
          style: Theme.of(context).textTheme.bodySmall,
        ),
      );
    }
    return ListView(
      shrinkWrap: true,
      children: [
        for (final user in results)
          ListTile(
            dense: true,
            leading: CircleAvatar(
              child: Text(
                user.displayName.trim().isNotEmpty
                    ? user.displayName.trim().substring(0, 1).toUpperCase()
                    : user.account.substring(0, 1).toUpperCase(),
              ),
            ),
            title: Text(user.displayName),
            subtitle: Text(user.account),
            trailing: _isMember(user)
                ? Text(
                    l10n.alreadyAdded,
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Theme.of(context).colorScheme.onSurfaceVariant,
                        ),
                  )
                : FilledButton.tonal(
                    onPressed: () => _invite(user),
                    child: Text(l10n.add),
                  ),
          ),
      ],
    );
  }
}

/// 首屏错误 + 重试。
class _ErrorRetryView extends StatelessWidget {
  const _ErrorRetryView({required this.message, required this.onRetry});

  final String message;
  final Future<void> Function() onRetry;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(Icons.cloud_off, size: 48),
          const SizedBox(height: 12),
          Text(message, textAlign: TextAlign.center),
          const SizedBox(height: 12),
          FilledButton.icon(
            onPressed: onRetry,
            icon: const Icon(Icons.refresh),
            label: Text(l10n.retry),
          ),
        ],
      ),
    );
  }
}