/**
 * GroupMembersScreen 群成员管理界面
 * 显示群成员列表，支持管理员管理成员
 * 支持响应式网格布局
 * 使用游标分页
 */

import React, { useState, useEffect, useCallback, useMemo, useRef } from 'react';
import {
  View,
  StyleSheet,
  FlatList,
  TouchableOpacity,
  Alert,
  RefreshControl,
  ListRenderItem,
  Modal,
  TextInput,
  Dimensions,
  Platform,
} from 'react-native';
import { SafeAreaView } from 'react-native-safe-area-context';
import { useLocalSearchParams, useRouter } from 'expo-router';
import { MaterialCommunityIcons } from '@expo/vector-icons';
import { blurActiveElement } from '../../infrastructure/platform';
import { spacing, fontSizes, borderRadius, useAppColors, type AppColors } from '../../theme';
import { useAuthStore } from '../../stores';
import { groupService } from '../../services/groupService';
import {
  createRemoteGroupMemberListSource,
  GroupMemberListSourceKind,
  IGroupMemberListPagedSource,
} from '../../stores/groupMemberListSources';
import { enrichGroupMembersWithUserProfiles } from '../../stores/groupMemberProfileResolver';
import { Avatar, Text, Button, Loading, EmptyState, Divider, ResponsiveContainer, AppBackButton } from '../../components/common';
import { useResponsive, useBreakpointGTE } from '../../hooks/useResponsive';
import { useCursorPagination } from '../../hooks/useCursorPagination';
import {
  GroupMemberResponse,
  GroupRole,
} from '../../types/dto';
import { firstRouteParam } from '../../navigation/paramUtils';
const { width: SCREEN_WIDTH } = Dimensions.get('window');
const GROUP_MEMBER_REMOTE_LIST_KIND: GroupMemberListSourceKind = 'cursor';

// 网格布局配置
const GRID_CONFIG = {
  mobile: { columns: 1, itemWidth: '100%' },
  tablet: { columns: 2, itemWidth: '48%' },
  desktop: { columns: 3, itemWidth: '31%' },
};

// 成员分组
interface MemberGroup {
  title: string;
  data: GroupMemberResponse[];
}

const GroupMembersScreen: React.FC = () => {
  const colors = useAppColors();
  const styles = useMemo(() => createGroupMembersStyles(colors), [colors]);
  const router = useRouter();
  const { groupId: groupIdParam } = useLocalSearchParams<{ groupId?: string | string[] }>();
  const groupId = firstRouteParam(groupIdParam) ?? '';
  const { currentUser } = useAuthStore();

  // 响应式布局
  const { isDesktop, isTablet, width } = useResponsive();
  const isWideScreen = useBreakpointGTE('lg');

  // 计算网格列数
  const gridConfig = useMemo(() => {
    if (width >= 1024) return GRID_CONFIG.desktop;
    if (width >= 768) return GRID_CONFIG.tablet;
    return GRID_CONFIG.mobile;
  }, [width]);

  const memberListSource = useMemo<IGroupMemberListPagedSource>(() => {
    return createRemoteGroupMemberListSource(GROUP_MEMBER_REMOTE_LIST_KIND, groupId, 50);
  }, [groupId]);

  // 使用统一数据源 + 游标 Hook 管理成员列表
  const {
    list: members,
    isLoading,
    isRefreshing,
    hasMore,
    loadMore,
    refresh,
    error,
  } = useCursorPagination(
    async ({ cursor }) => {
      // cursor 为空表示第一页/刷新，此时重置数据源状态
      if (!cursor) {
        memberListSource.restart();
      }
      return await memberListSource.loadNext();
    },
    { pageSize: 50 }
  );

  // 本地成员状态（用于乐观更新）
  const [localMembers, setLocalMembers] = useState<GroupMemberResponse[]>([]);
  const [loading, setLoading] = useState(true);

  // 同步分页数据到本地状态
  useEffect(() => {
    let active = true;

    const syncMembers = async () => {
      const enrichedMembers = await enrichGroupMembersWithUserProfiles(members);
      if (!active) return;
      setLocalMembers(enrichedMembers);
      setLoading(false);
    };

    syncMembers();

    return () => {
      active = false;
    };
  }, [members]);

  // 当前用户的成员信息
  const [currentMember, setCurrentMember] = useState<GroupMemberResponse | null>(null);

  // 操作模态框状态
  const [actionModalVisible, setActionModalVisible] = useState(false);
  const [selectedMember, setSelectedMember] = useState<GroupMemberResponse | null>(null);
  const [actionLoading, setActionLoading] = useState(false);

  // 设置群昵称模态框
  const [nicknameModalVisible, setNicknameModalVisible] = useState(false);
  const [newNickname, setNewNickname] = useState('');

  useEffect(() => {
    if (actionModalVisible || nicknameModalVisible) {
      blurActiveElement();
    }
  }, [actionModalVisible, nicknameModalVisible]);

  // 计算当前用户的角色
  const isOwner = currentMember?.role === 'owner';
  const isAdmin = currentMember?.role === 'admin' || isOwner;

  // 查找当前用户的成员信息
  useEffect(() => {
    const myMember = localMembers.find(m => m.user_id === currentUser?.id);
    if (myMember) {
      setCurrentMember(myMember);
    }
  }, [localMembers, currentUser]);

  // 下拉刷新
  const onRefresh = useCallback(async () => {
    setLoading(true);
    await refresh();
    setLoading(false);
  }, [refresh]);

  // 初始加载 - 使用 ref 避免依赖变化导致的无限循环
  const initialLoadRef = React.useRef(false);
  useEffect(() => {
    if (!groupId || initialLoadRef.current) return;
    initialLoadRef.current = true;
    refresh();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [groupId]);

  // 按角色分组
  const groupMembers = useCallback((): MemberGroup[] => {
    const owners = localMembers.filter(m => m.role === 'owner');
    const admins = localMembers.filter(m => m.role === 'admin');
    const normalMembers = localMembers.filter(m => m.role === 'member');

    const groups: MemberGroup[] = [];

    if (owners.length > 0) {
      groups.push({ title: '群主', data: owners });
    }
    if (admins.length > 0) {
      groups.push({ title: '管理员', data: admins });
    }
    if (normalMembers.length > 0) {
      groups.push({ title: '成员', data: normalMembers });
    }

    return groups;
  }, [localMembers]);

  // 打开操作菜单
  const openActionModal = (member: GroupMemberResponse) => {
    // 不能操作群主
    if (member.role === 'owner') return;
    
    // 普通成员不能操作其他人
    if (!isAdmin) return;
    
    // 管理员不能操作其他管理员（只有群主可以）
    if (!isOwner && member.role === 'admin') return;

    setSelectedMember(member);
    setActionModalVisible(true);
  };

  // 设置/取消管理员
  const handleToggleAdmin = async () => {
    if (!selectedMember) return;

    const newRole: GroupRole = selectedMember.role === 'admin' ? 'member' : 'admin';
    const actionText = newRole === 'admin' ? '设为管理员' : '取消管理员';

    Alert.alert(
      actionText,
      `确定要${actionText} "${selectedMember.user?.nickname || selectedMember.nickname}" 吗？`,
      [
        { text: '取消', style: 'cancel' },
        {
          text: '确定',
          onPress: async () => {
            setActionLoading(true);
            try {
              await groupService.setMemberRole(groupId, selectedMember.user_id, {
                role: newRole as 'admin' | 'member',
              });
              
              // 更新本地数据
              setLocalMembers(prev => prev.map(m => {
                if (m.user_id === selectedMember.user_id) {
                  return { ...m, role: newRole };
                }
                return m;
              }));

              setActionModalVisible(false);
              Alert.alert('成功', `已${actionText}`);
            } catch (error: any) {
              console.error('设置角色失败:', error);
              Alert.alert('错误', error.message || '操作失败');
            } finally {
              setActionLoading(false);
            }
          },
        },
      ]
    );
  };

  // 禁言/解禁成员
  const handleToggleMute = async () => {
    if (!selectedMember) return;

    const newMuted = !selectedMember.muted;
    const actionText = newMuted ? '禁言' : '解禁';

    Alert.alert(
      `${actionText}成员`,
      `确定要${actionText} "${selectedMember.user?.nickname || selectedMember.nickname}" 吗？`,
      [
        { text: '取消', style: 'cancel' },
        {
          text: '确定',
          onPress: async () => {
            setActionLoading(true);
            try {
              // duration: 0 表示解除禁言，-1 表示永久禁言
              await groupService.muteMember(groupId, selectedMember.user_id, newMuted ? -1 : 0);

              // 更新本地数据
              setLocalMembers(prev => prev.map(m => {
                if (m.user_id === selectedMember.user_id) {
                  return { ...m, muted: newMuted };
                }
                return m;
              }));
              // 强制刷新远端状态，避免命中旧缓存导致解禁后仍显示禁言
              await refresh();

              setActionModalVisible(false);
              Alert.alert('成功', `已${actionText}`);
            } catch (error: any) {
              console.error('禁言操作失败:', error);
              Alert.alert('错误', error.message || '操作失败');
            } finally {
              setActionLoading(false);
            }
          },
        },
      ]
    );
  };

  // 移除成员
  const handleRemoveMember = () => {
    if (!selectedMember) return;

    Alert.alert(
      '移除成员',
      `确定要将 "${selectedMember.user?.nickname || selectedMember.nickname}" 移出群聊吗？`,
      [
        { text: '取消', style: 'cancel' },
        {
          text: '移除',
          style: 'destructive',
          onPress: async () => {
            setActionLoading(true);
            try {
              await groupService.removeMember(groupId, selectedMember.user_id);

              // 更新本地数据
              setLocalMembers(prev => prev.filter(m => m.user_id !== selectedMember.user_id));

              setActionModalVisible(false);
              Alert.alert('成功', '已移除成员');
            } catch (error: any) {
              console.error('移除成员失败:', error);
              Alert.alert('错误', error.message || '操作失败');
            } finally {
              setActionLoading(false);
            }
          },
        },
      ]
    );
  };

  // 打开设置群昵称模态框
  const openNicknameModal = (member: GroupMemberResponse) => {
    setSelectedMember(member);
    setNewNickname(member.nickname || member.user?.nickname || '');
    setNicknameModalVisible(true);
  };

  // 设置群昵称（仅限自己）
  const handleSetNickname = async () => {
    if (!selectedMember || selectedMember.user_id !== currentUser?.id) return;

    setActionLoading(true);
    try {
      await groupService.setNickname(groupId, {
        nickname: newNickname.trim() || selectedMember.user?.nickname || '',
      });

      // 更新本地数据
      setLocalMembers(prev => prev.map(m => {
        if (m.user_id === selectedMember.user_id) {
          return { ...m, nickname: newNickname.trim() };
        }
        return m;
      }));

      setNicknameModalVisible(false);
      Alert.alert('成功', '群昵称已更新');
    } catch (error: any) {
      console.error('设置群昵称失败:', error);
      Alert.alert('错误', error.message || '操作失败');
    } finally {
      setActionLoading(false);
    }
  };

  // 获取角色标签颜色
  const getRoleBadgeColor = (role: GroupRole): string => {
    switch (role) {
      case 'owner':
        return colors.warning.main;
      case 'admin':
        return colors.primary.main;
      default:
        return colors.text.hint;
    }
  };

  // 获取角色标签文本
  const getRoleBadgeText = (role: GroupRole): string => {
    switch (role) {
      case 'owner':
        return '群主';
      case 'admin':
        return '管理员';
      default:
        return '';
    }
  };

  // 渲染成员项
  const renderMember: ListRenderItem<GroupMemberResponse> = ({ item }) => {
    const isSelf = item.user_id === currentUser?.id;
    const canManage = isAdmin && item.role !== 'owner' && (isOwner || item.role === 'member');

    return (
      <TouchableOpacity
        style={styles.memberItem}
        onPress={() => canManage ? openActionModal(item) : null}
        onLongPress={() => isSelf ? openNicknameModal(item) : null}
        activeOpacity={canManage ? 0.7 : 1}
      >
        <Avatar
          source={item.user?.avatar}
          size={48}
          name={item.user?.nickname || item.nickname}
        />
        <View style={styles.memberInfo}>
          <View style={styles.memberNameRow}>
            <Text variant="body" style={styles.memberName}>
              {item.nickname || item.user?.nickname || '未知用户'}
            </Text>
            {item.role !== 'member' && (
              <View style={[styles.roleBadge, { backgroundColor: getRoleBadgeColor(item.role) }]}>
                <Text variant="label" color={colors.background.paper}>
                  {getRoleBadgeText(item.role)}
                </Text>
              </View>
            )}
          </View>
          <Text variant="caption" color={colors.text.secondary}>
            @{item.user?.username || 'unknown'}
          </Text>
          {item.muted && (
            <View style={styles.mutedBadge}>
              <MaterialCommunityIcons name="microphone-off" size={12} color={colors.error.main} />
              <Text variant="label" color={colors.error.main}> 禁言中</Text>
            </View>
          )}
        </View>
        {canManage && (
          <MaterialCommunityIcons name="dots-vertical" size={20} color={colors.text.hint} />
        )}
      </TouchableOpacity>
    );
  };

  // 渲染分组头部
  const renderSectionHeader = (title: string, count: number) => (
    <View style={styles.sectionHeader}>
      <Text variant="label" color={colors.text.secondary}>
        {title}
      </Text>
      <Text variant="caption" color={colors.text.hint}>
        {count}人
      </Text>
    </View>
  );

  // 渲染空状态
  const renderEmpty = () => {
    if (loading || isLoading) return <Loading />;
    
    return (
      <EmptyState
        title="暂无成员"
        description="群组还没有成员"
        icon="account-group-outline"
      />
    );
  };

  // 渲染操作菜单
  const renderActionModal = () => {
    if (!selectedMember) return null;

    return (
      <Modal
        visible={actionModalVisible}
        animationType="slide"
        transparent
        onRequestClose={() => setActionModalVisible(false)}
      >
        <View style={styles.modalOverlay}>
          <View style={styles.modalContent}>
            <View style={styles.modalHeader}>
              <Avatar
                source={selectedMember.user?.avatar}
                size={60}
                name={selectedMember.user?.nickname || selectedMember.nickname}
              />
              <Text variant="h3" style={styles.modalTitle}>
                {selectedMember.user?.nickname || selectedMember.nickname}
              </Text>
              <Text variant="caption" color={colors.text.secondary}>
                @{selectedMember.user?.username}
              </Text>
            </View>

            <Divider />

            {/* 设置/取消管理员（仅群主） */}
            {isOwner && selectedMember.role !== 'owner' && (
              <TouchableOpacity
                style={styles.actionItem}
                onPress={handleToggleAdmin}
                disabled={actionLoading}
              >
                <MaterialCommunityIcons
                  name={selectedMember.role === 'admin' ? 'account-remove' : 'account-plus'}
                  size={22}
                  color={colors.text.primary}
                />
                <Text variant="body" style={styles.actionText}>
                  {selectedMember.role === 'admin' ? '取消管理员' : '设为管理员'}
                </Text>
              </TouchableOpacity>
            )}

            {/* 禁言/解禁 */}
            <TouchableOpacity
              style={styles.actionItem}
              onPress={handleToggleMute}
              disabled={actionLoading}
            >
              <MaterialCommunityIcons
                name={selectedMember.muted ? 'microphone' : 'microphone-off'}
                size={22}
                color={selectedMember.muted ? colors.success.main : colors.error.main}
              />
              <Text
                variant="body"
                color={selectedMember.muted ? colors.success.main : colors.error.main}
                style={styles.actionText}
              >
                {selectedMember.muted ? '解除禁言' : '禁言'}
              </Text>
            </TouchableOpacity>

            {/* 移除成员 */}
            <TouchableOpacity
              style={styles.actionItem}
              onPress={handleRemoveMember}
              disabled={actionLoading}
            >
              <MaterialCommunityIcons name="account-remove" size={22} color={colors.error.main} />
              <Text variant="body" color={colors.error.main} style={styles.actionText}>
                移除成员
              </Text>
            </TouchableOpacity>

            <Divider />

            <Button
              title="取消"
              variant="outline"
              onPress={() => setActionModalVisible(false)}
              fullWidth
              disabled={actionLoading}
            />
          </View>
        </View>
      </Modal>
    );
  };

  // 渲染设置群昵称模态框
  const renderNicknameModal = () => {
    if (!selectedMember) return null;

    return (
      <Modal
        visible={nicknameModalVisible}
        animationType="slide"
        transparent
        onRequestClose={() => setNicknameModalVisible(false)}
      >
        <View style={styles.modalOverlay}>
          <View style={styles.modalContent}>
            <Text variant="h3" style={styles.modalTitle}>设置群昵称</Text>
            
            <Text variant="caption" color={colors.text.secondary} style={styles.inputLabel}>
              在本群的昵称（选填）
            </Text>
            <TextInput
              style={styles.input}
              value={newNickname}
              onChangeText={setNewNickname}
              placeholder={selectedMember.user?.nickname || '请输入群昵称'}
              placeholderTextColor={colors.text.hint}
              maxLength={20}
            />

            <View style={styles.modalButtons}>
              <Button
                title="取消"
                variant="outline"
                onPress={() => setNicknameModalVisible(false)}
                style={styles.modalButton}
                disabled={actionLoading}
              />
              <Button
                title="保存"
                onPress={handleSetNickname}
                loading={actionLoading}
                style={styles.modalButton}
              />
            </View>
          </View>
        </View>
      </Modal>
    );
  };

  // 渲染分组列表
  const renderGroupedList = () => {
    const groups = groupMembers();

    if (groups.length === 0) {
      return renderEmpty();
    }

    return (
      <FlatList
        data={groups}
        keyExtractor={(item) => item.title}
        refreshControl={
          <RefreshControl
            refreshing={isRefreshing}
            onRefresh={onRefresh}
            colors={[colors.primary.main]}
            tintColor={colors.primary.main}
          />
        }
        onEndReached={loadMore}
        onEndReachedThreshold={0.3}
        showsVerticalScrollIndicator={false}
        ListFooterComponent={
          isLoading ? (
            <View style={styles.loadingFooter}>
              <Loading size="sm" />
            </View>
          ) : hasMore ? (
            <TouchableOpacity style={styles.loadMoreBtn} onPress={loadMore}>
              <Text variant="caption" color={colors.primary.main}>
                加载更多成员
              </Text>
            </TouchableOpacity>
          ) : localMembers.length > 0 ? (
            <Text variant="caption" color={colors.text.hint} style={styles.noMoreText}>
              没有更多成员了
            </Text>
          ) : null
        }
        renderItem={({ item: group }) => (
          <View style={styles.section}>
            {renderSectionHeader(group.title, group.data.length)}
            {group.data.map((member, index) => (
              <View key={member.id}>
                {renderMember({ item: member, index } as any)}
              </View>
            ))}
          </View>
        )}
      />
    );
  };

  return (
    <SafeAreaView style={styles.container} edges={['top', 'bottom']}>
      {/* Header */}
      <View style={styles.pageHeader}>
        <AppBackButton onPress={() => router.back()} />
        <Text variant="h3" style={styles.pageTitle}>群成员</Text>
        <View style={styles.pageHeaderPlaceholder} />
      </View>
      {loading ? <Loading /> : renderGroupedList()}
      {renderActionModal()}
      {renderNicknameModal()}
    </SafeAreaView>
  );
};

function createGroupMembersStyles(colors: AppColors) {
  return StyleSheet.create({
    container: {
      flex: 1,
      backgroundColor: colors.background.default,
    },
    // Header 样式 - 扁平化
    pageHeader: {
      flexDirection: 'row',
      alignItems: 'center',
      justifyContent: 'space-between',
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.md,
      backgroundColor: colors.background.paper,
      borderBottomWidth: 0.5,
      borderBottomColor: colors.divider + '60',
    },
    pageTitle: {
      fontWeight: '800',
      fontSize: fontSizes.xl + 1,
      letterSpacing: 0.5,
    },
    pageHeaderPlaceholder: {
      width: 40,
    },
    section: {
      marginBottom: spacing.md,
    },
    sectionHeader: {
      flexDirection: 'row',
      justifyContent: 'space-between',
      alignItems: 'center',
      paddingHorizontal: spacing.lg,
      paddingVertical: spacing.md,
      backgroundColor: colors.background.default,
      borderTopWidth: 0.5,
      borderTopColor: colors.divider + '40',
    },
    memberItem: {
      flexDirection: 'row',
      alignItems: 'center',
      paddingHorizontal: spacing.lg,
      paddingVertical: spacing.md,
      backgroundColor: colors.background.paper,
      borderBottomWidth: 0.5,
      borderBottomColor: colors.divider + '40',
    },
    memberInfo: {
      flex: 1,
      marginLeft: spacing.md,
    },
    memberNameRow: {
      flexDirection: 'row',
      alignItems: 'center',
      marginBottom: 2,
    },
    memberName: {
      fontWeight: '700',
      fontSize: fontSizes.md + 1,
      letterSpacing: 0.3,
    },
    roleBadge: {
      paddingHorizontal: spacing.sm,
      paddingVertical: 2,
      borderRadius: borderRadius.sm,
      marginLeft: spacing.sm,
      fontWeight: '800',
      fontSize: fontSizes.xs,
      color: colors.background.paper,
    },
    mutedBadge: {
      flexDirection: 'row',
      alignItems: 'center',
      marginTop: 2,
    },
    // 模态框样式 - 更现代
    modalOverlay: {
      flex: 1,
      backgroundColor: 'rgba(0, 0, 0, 0.45)',
      justifyContent: 'flex-end',
    },
    modalContent: {
      backgroundColor: colors.background.paper,
      borderTopLeftRadius: borderRadius['2xl'],
      borderTopRightRadius: borderRadius['2xl'],
      padding: spacing.lg,
      maxHeight: '80%',
    },
    modalHeader: {
      alignItems: 'center',
      marginBottom: spacing.lg,
      paddingBottom: spacing.md,
      borderBottomWidth: 0.5,
      borderBottomColor: colors.divider + '60',
    },
    modalTitle: {
      fontWeight: '800',
      fontSize: fontSizes.xl + 1,
      marginTop: spacing.sm,
      marginBottom: spacing.xs,
      letterSpacing: 0.5,
    },
    actionItem: {
      flexDirection: 'row',
      alignItems: 'center',
      paddingVertical: spacing.md,
      paddingHorizontal: spacing.sm,
      marginLeft: -spacing.sm,
      marginRight: -spacing.sm,
      borderRadius: borderRadius.md,
      borderBottomWidth: 0.5,
      borderBottomColor: colors.divider + '40',
    },
    actionText: {
      marginLeft: spacing.md,
      fontWeight: '600',
      fontSize: fontSizes.md,
    },
    inputLabel: {
      marginBottom: spacing.xs,
      fontWeight: '700',
      fontSize: fontSizes.sm + 1,
    },
    input: {
      backgroundColor: colors.background.default,
      borderRadius: borderRadius.lg,
      paddingHorizontal: spacing.md,
      paddingVertical: spacing.md,
      fontSize: fontSizes.md,
      color: colors.text.primary,
      borderWidth: 1.5,
      borderColor: colors.divider + '80',
      marginBottom: spacing.md,
    },
    modalButtons: {
      flexDirection: 'row',
      justifyContent: 'space-between',
      marginTop: spacing.md,
    },
    modalButton: {
      flex: 1,
      marginHorizontal: spacing.xs,
    },
    // 分页加载样式
    loadingFooter: {
      paddingVertical: spacing.md,
      alignItems: 'center',
    },
    loadMoreBtn: {
      paddingVertical: spacing.md,
      alignItems: 'center',
    },
    noMoreText: {
      textAlign: 'center',
      paddingVertical: spacing.md,
      fontWeight: '500',
      color: colors.text.hint,
    },
  });
}

export default GroupMembersScreen;
