import { useEffect, useState, useRef } from "react";

import { type Employee } from "../../services/api";

// 多选用户下拉框组件 - 带 tag 显示
export function UserMultiSelect({
  users,
  selectedUserIds,
  onChange,
  existingMemberIds,
}: {
  users: Employee[];
  selectedUserIds: string[];
  onChange: (ids: string[]) => void;
  existingMemberIds?: string[];
}) {
  const [isOpen, setIsOpen] = useState(false);
  const containerRef = useRef<HTMLDivElement>(null);

  // 点击外部关闭下拉框
  useEffect(() => {
    const handleClickOutside = (event: MouseEvent) => {
      if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
        setIsOpen(false);
      }
    };
    document.addEventListener("mousedown", handleClickOutside);
    return () => document.removeEventListener("mousedown", handleClickOutside);
  }, []);

  const selectedUsers = users.filter((user) => selectedUserIds.includes(user.user_id));

  const toggleUser = (userId: string) => {
    if (selectedUserIds.includes(userId)) {
      onChange(selectedUserIds.filter((id) => id !== userId));
    } else {
      onChange([...selectedUserIds, userId]);
    }
  };

  const removeUser = (userId: string, event: React.MouseEvent) => {
    event.stopPropagation();
    onChange(selectedUserIds.filter((id) => id !== userId));
  };

  return (
    <div ref={containerRef} style={{ position: "relative" }}>
      {/* 选择框 - 显示 tag */}
      <div
        className="admin-toolbar__input"
        onClick={() => setIsOpen(!isOpen)}
        style={{
          display: "flex",
          alignItems: "center",
          flexWrap: "wrap",
          gap: "4px",
          padding: "6px 32px 6px 8px",
          minHeight: "36px",
          border: "1px solid #ddd",
          borderRadius: "4px",
          cursor: "pointer",
          backgroundColor: "#fff",
        }}
      >
        {selectedUsers.length === 0 ? (
          <span style={{ color: "#999" }}>请选择用户</span>
        ) : (
          selectedUsers.map((user) => (
            <span
              key={user.user_id}
              style={{
                display: "inline-flex",
                alignItems: "center",
                backgroundColor: "#e6f7ff",
                color: "#1890ff",
                border: "1px solid #91d5ff",
                borderRadius: "2px",
                padding: "2px 6px",
                fontSize: "13px",
              }}
            >
              {user.display_name}
              <span
                onClick={(e) => removeUser(user.user_id, e)}
                style={{
                  marginLeft: "4px",
                  cursor: "pointer",
                  fontWeight: "bold",
                  fontSize: "14px",
                }}
              >
                ×
              </span>
            </span>
          ))
        )}
        <span
          style={{
            position: "absolute",
            right: "12px",
            top: "50%",
            transform: "translateY(-50%)",
            color: "#999",
            pointerEvents: "none",
          }}
        >
          {isOpen ? "▲" : "▼"}
        </span>
      </div>

      {/* 下拉列表 */}
      {isOpen && (
        <div
          style={{
            position: "absolute",
            top: "100%",
            left: 0,
            right: 0,
            maxHeight: "136px",
            overflowY: "auto",
            border: "1px solid #1890ff",
            borderRadius: "4px",
            backgroundColor: "#fff",
            zIndex: 100,
            marginTop: "2px",
            boxShadow: "0 2px 8px rgba(0,0,0,0.15)",
          }}
        >
          {users.length === 0 ? (
            <div style={{ padding: "12px", color: "#999", textAlign: "center", fontSize: "13px" }}>
              所有可选用户已在项目中
            </div>
          ) : (
            users.map((user) => {
              const isSelected = selectedUserIds.includes(user.user_id);
              const isExisting = existingMemberIds?.includes(user.user_id);
              const isDisabled = isExisting;
              return (
                <div
                  key={user.user_id}
                  onClick={() => !isDisabled && toggleUser(user.user_id)}
                  style={{
                    display: "flex",
                    justifyContent: "space-between",
                    alignItems: "center",
                    padding: "6px 12px",
                    cursor: isDisabled ? "not-allowed" : "pointer",
                    backgroundColor: isSelected ? "#e6f7ff" : isExisting ? "#f5f5f5" : "transparent",
                    borderBottom: "1px solid #f0f0f0",
                    opacity: isDisabled ? 0.6 : 1,
                  }}
                >
                  <span>
                    {user.display_name} <span style={{ color: "#999" }}>({user.username})</span>
                  </span>
                  <div style={{ display: "flex", alignItems: "center", gap: "6px" }}>
                    {isExisting && (
                      <span style={{ fontSize: "11px", color: "#999", backgroundColor: "#f0f0f0", padding: "1px 6px", borderRadius: "2px" }}>
                        已在项目中
                      </span>
                    )}
                    {isSelected && <span style={{ color: "#1890ff" }}>✓</span>}
                  </div>
                </div>
              );
            })
          )}
        </div>
      )}
    </div>
  );
}