import { useCallback, useEffect, useState } from 'react';
import type { Role, User } from '../../types';
import { api } from '../../utils/api';

type FilterStatus = 'ALL' | 'PENDING' | 'ACTIVE' | 'REJECTED' | 'DISABLED';

export function UserManagement() {
  const [users, setUsers] = useState<User[]>([]);
  const [roles, setRoles] = useState<Role[]>([]);
  const [filter, setFilter] = useState<FilterStatus>('ALL');
  const [loading, setLoading] = useState(true);
  const [roleModalUser, setRoleModalUser] = useState<User | null>(null);
  const [selectedRoleIds, setSelectedRoleIds] = useState<number[]>([]);

  const fetchData = useCallback(async () => {
    try {
      const [usersData, rolesData] = await Promise.all([
        api.get<User[]>('/admin/users'),
        api.get<Role[]>('/admin/roles'),
      ]);
      setUsers(usersData);
      setRoles(rolesData);
    } catch {
      // API 미연동 시 빈 배열 유지
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    fetchData();
  }, [fetchData]);

  const handleAction = async (userId: number, action: 'approve' | 'reject' | 'disable') => {
    try {
      await api.put<User>(`/admin/users/${userId}/${action}`, {});
      fetchData();
    } catch {
      // 에러 처리
    }
  };

  const handleToggleAdmin = async (userId: number, isAdmin: boolean) => {
    try {
      if (isAdmin) {
        await api.delete(`/admin/users/${userId}/admin`);
      } else {
        await api.post(`/admin/users/${userId}/admin`);
      }
      fetchData();
    } catch {
      // 에러 처리
    }
  };

  const handleRoleSave = async () => {
    if (!roleModalUser) return;
    try {
      await api.put<User>(`/admin/users/${roleModalUser.id}/roles`, { roleIds: selectedRoleIds });
      setRoleModalUser(null);
      fetchData();
    } catch {
      // 에러 처리
    }
  };

  const filteredUsers = filter === 'ALL' ? users : users.filter((u) => u.status === filter);

  const statusBadge = (status: User['status']) => {
    const styles: Record<string, string> = {
      ACTIVE: 'bg-success/10 text-success',
      PENDING: 'bg-warning/10 text-warning',
      REJECTED: 'bg-danger/10 text-danger',
      DISABLED: 'bg-bg-tertiary text-text-muted',
    };
    const labels: Record<string, string> = {
      ACTIVE: '활성', PENDING: '대기', REJECTED: '거절', DISABLED: '비활성',
    };
    return (
      <span className={`px-2 py-0.5 rounded-full text-xs font-medium ${styles[status]}`}>
        {labels[status]}
      </span>
    );
  };

  if (loading) {
    return (
      <div className="flex items-center justify-center py-20">
        <div className="animate-spin h-6 w-6 border-3 border-accent border-t-transparent rounded-full" />
      </div>
    );
  }

  return (
    <div className="p-8">
      <h1 className="text-2xl font-bold text-text-primary mb-6">사용자 관리</h1>

      {/* 필터 */}
      <div className="flex gap-2 mb-6">
        {(['ALL', 'PENDING', 'ACTIVE', 'REJECTED', 'DISABLED'] as FilterStatus[]).map((s) => (
          <button
            key={s}
            onClick={() => setFilter(s)}
            className={`px-3 py-1.5 rounded-lg text-sm cursor-pointer transition-colors ${
              filter === s
                ? 'bg-accent text-white'
                : 'bg-surface border border-border-default text-text-secondary hover:bg-bg-tertiary'
            }`}
          >
            {s === 'ALL' ? '전체' : s === 'PENDING' ? '대기' : s === 'ACTIVE' ? '활성' : s === 'REJECTED' ? '거절' : '비활성'}
            {s !== 'ALL' && (
              <span className="ml-1 text-xs opacity-70">
                ({users.filter((u) => u.status === s).length})
              </span>
            )}
          </button>
        ))}
      </div>

      {/* 테이블 */}
      <div className="overflow-x-auto">
        <table className="w-full bg-surface border border-border-default rounded-lg overflow-hidden text-sm">
          <thead>
            <tr className="bg-bg-tertiary">
              <th className="text-left px-4 py-3 font-semibold text-text-primary">사용자</th>
              <th className="text-left px-4 py-3 font-semibold text-text-primary">상태</th>
              <th className="text-left px-4 py-3 font-semibold text-text-primary">롤</th>
              <th className="text-left px-4 py-3 font-semibold text-text-primary">가입일</th>
              <th className="text-left px-4 py-3 font-semibold text-text-primary">작업</th>
            </tr>
          </thead>
          <tbody className="divide-y divide-border-subtle">
            {filteredUsers.length === 0 ? (
              <tr>
                <td colSpan={5} className="px-4 py-8 text-center text-text-muted">
                  {users.length === 0 ? '등록된 사용자가 없습니다.' : '해당 상태의 사용자가 없습니다.'}
                </td>
              </tr>
            ) : (
              filteredUsers.map((user) => (
                <tr key={user.id}>
                  <td className="px-4 py-3">
                    <div className="flex items-center gap-3">
                      {user.avatarUrl ? (
                        <img src={user.avatarUrl} alt="" className="w-8 h-8 rounded-full" />
                      ) : (
                        <div className="w-8 h-8 bg-accent-soft rounded-full flex items-center justify-center text-xs font-medium text-accent">
                          {user.name[0]}
                        </div>
                      )}
                      <div>
                        <p className="font-medium text-text-primary">
                          {user.name}
                          {user.isAdmin && (
                            <span className="ml-1.5 px-1.5 py-0.5 bg-accent/10 text-accent rounded text-[10px] font-semibold align-middle">
                              ADMIN
                            </span>
                          )}
                        </p>
                        <p className="text-xs text-text-muted">{user.email}</p>
                      </div>
                    </div>
                  </td>
                  <td className="px-4 py-3">{statusBadge(user.status)}</td>
                  <td className="px-4 py-3 text-text-secondary">
                    {user.roles.length > 0
                      ? user.roles.map((r) => r.name).join(', ')
                      : <span className="text-text-muted">미배정</span>}
                  </td>
                  <td className="px-4 py-3 text-text-muted text-xs">
                    {new Date(user.createdAt).toLocaleDateString('ko-KR')}
                  </td>
                  <td className="px-4 py-3">
                    <div className="flex gap-1.5">
                      {user.status === 'PENDING' && (
                        <>
                          <button
                            onClick={() => handleAction(user.id, 'approve')}
                            className="px-2.5 py-1 bg-success/10 text-success rounded text-xs font-medium hover:bg-success/20 cursor-pointer"
                          >
                            승인
                          </button>
                          <button
                            onClick={() => handleAction(user.id, 'reject')}
                            className="px-2.5 py-1 bg-danger/10 text-danger rounded text-xs font-medium hover:bg-danger/20 cursor-pointer"
                          >
                            거절
                          </button>
                        </>
                      )}
                      {user.status === 'ACTIVE' && (
                        <button
                          onClick={() => handleAction(user.id, 'disable')}
                          className="px-2.5 py-1 bg-bg-tertiary text-text-muted rounded text-xs font-medium hover:bg-border-default cursor-pointer"
                        >
                          비활성화
                        </button>
                      )}
                      <button
                        onClick={() => {
                          setRoleModalUser(user);
                          setSelectedRoleIds(user.roles.map((r) => r.id));
                        }}
                        className="px-2.5 py-1 bg-accent-soft text-accent rounded text-xs font-medium hover:bg-accent/20 cursor-pointer"
                      >
                        롤 배정
                      </button>
                      {user.status === 'ACTIVE' && (
                        <button
                          onClick={() => handleToggleAdmin(user.id, user.isAdmin)}
                          className={`px-2.5 py-1 rounded text-xs font-medium cursor-pointer ${
                            user.isAdmin
                              ? 'bg-warning/10 text-warning hover:bg-warning/20'
                              : 'bg-info/10 text-info hover:bg-info/20'
                          }`}
                        >
                          {user.isAdmin ? '관리자 해제' : '관리자 지정'}
                        </button>
                      )}
                    </div>
                  </td>
                </tr>
              ))
            )}
          </tbody>
        </table>
      </div>

      {/* 롤 배정 모달 */}
      {roleModalUser && (
        <div className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
          <div className="bg-surface rounded-xl shadow-xl max-w-md w-full p-6">
            <h3 className="text-lg font-bold text-text-primary mb-4">
              롤 배정 — {roleModalUser.name}
            </h3>
            <div className="space-y-2 mb-6">
              {roles.map((role) => (
                <label key={role.id} className="flex items-center gap-3 p-2 rounded-lg hover:bg-bg-tertiary cursor-pointer">
                  <input
                    type="checkbox"
                    checked={selectedRoleIds.includes(role.id)}
                    onChange={(e) => {
                      setSelectedRoleIds(
                        e.target.checked
                          ? [...selectedRoleIds, role.id]
                          : selectedRoleIds.filter((id) => id !== role.id),
                      );
                    }}
                    className="rounded accent-accent"
                  />
                  <div>
                    <p className="text-sm font-medium text-text-primary">{role.name}</p>
                    <p className="text-xs text-text-muted">{role.description}</p>
                  </div>
                </label>
              ))}
              {roles.length === 0 && (
                <p className="text-sm text-text-muted py-4 text-center">등록된 롤이 없습니다.</p>
              )}
            </div>
            <div className="flex justify-end gap-2">
              <button
                onClick={() => setRoleModalUser(null)}
                className="px-4 py-2 text-sm text-text-secondary border border-border-default rounded-lg hover:bg-bg-tertiary cursor-pointer"
              >
                취소
              </button>
              <button
                onClick={handleRoleSave}
                className="px-4 py-2 text-sm bg-accent text-white rounded-lg hover:bg-accent-hover cursor-pointer"
              >
                저장
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}