import React, {
  FC,
  createContext,
  useEffect,
  useState,
  useRef,
  FunctionComponentElement
} from 'react';
import { ISelectOptionProps } from './options';
import classNames from 'classnames';
import useClickOutside from '../../hooks/useClickOutside';
import Icon from '../Icon/Icon';
import Input from '../Input/input';
import Transition from '../Transition/transition';

export interface ISelectProps {
  // 指定默认选中的条目	 可以是是字符串或者字符串数组
  defaultValue?: string | string[];
  items?: ISelectOptionProps[];
  // 选择框默认文字
  placeholder?: string;
  // 是否禁用
  disabled?: boolean;
  // 是否多选
  multiple?: boolean;
  // select input 的 name 属性
  name?: string;
  // 选中值发生变化时触发
  onChange?: (selectedValue: string, selectedValues: string[]) => void;
  // 下拉框出现/隐藏时触发
  onVisibleChange?: (visible: boolean) => void;
  children?: React.ReactNode;
}

export interface ISelectContext {
  onSelect?: (value: string, isSelected?: boolean) => void;
  selectedValues: string[];
  multiple?: boolean;
}

export const SelectContext = createContext<ISelectContext>({
  selectedValues: []
});

const Select: FC<ISelectProps> = (props) => {
  const {
    defaultValue,
    items,
    placeholder,
    disabled,
    multiple,
    name,
    onChange,
    onVisibleChange,
    children
  } = props;

  const input = useRef<HTMLInputElement>(null);
  const containerRef = useRef<HTMLInputElement>(null);
  const containerWidth = useRef(0);
  const [selectedValues, setSelectedValues] = useState<string[]>(
    Array.isArray(defaultValue) ? defaultValue : []
  );
  const [menuOpen, setMenuOpen] = useState<boolean>(false);
  const [value, setValue] = useState(
    typeof defaultValue === 'string' ? defaultValue : ''
  );

  const handleOptionClick = (value: string, isSelected?: boolean) => {
    if (!multiple) {
      setMenuOpen(false);
      setValue(value);
      if (onVisibleChange) {
        onVisibleChange(false);
      }
    } else {
      setValue('');
    }

    let updateValues = [value];
    if (multiple) {
      updateValues = isSelected
        ? selectedValues.filter((v) => v !== value)
        : [...selectedValues, value];
        
      setSelectedValues(updateValues);
    }

    if (onChange) {
      onChange(value, updateValues);
    }
  };

  useEffect(() => {
    const inputElement = input.current;
    if (inputElement) {
      inputElement.focus();
      if (multiple && selectedValues.length > 0) {
        inputElement.placeholder = '';
      } else {
        if (placeholder) inputElement.placeholder = placeholder;
      }
    }
  }, [selectedValues, multiple, placeholder]);

  useEffect(() => {
    if (containerRef.current) {
      containerWidth.current =
        containerRef.current.getBoundingClientRect().width;
    }
  });
  useClickOutside(containerRef, () => {
    setMenuOpen(false);
    if (onVisibleChange && menuOpen) {
      onVisibleChange(false);
    }
  });

  const passedContext: ISelectContext = {
    onSelect: handleOptionClick,
    multiple: multiple,
    selectedValues: selectedValues
  };

  const handleClick = (e: React.MouseEvent) => {
    e.preventDefault();
    if (!disabled) {
      setMenuOpen(!menuOpen);
      if (onVisibleChange) {
        onVisibleChange(!menuOpen);
      }
    }
  };

  const containerClass = classNames('tui-select', {
    'menu-is-open': menuOpen,
    'is-disabled': disabled,
    'is-multiple': multiple
  });

  const generateOptions = () => {
    if (items) {
      return items.map((item, index) => {
        const isSelected = selectedValues.includes(item.value);
        const optionsClasses = classNames('tui-select-item', {
          'is-disabled': disabled,
          'is-selected': isSelected,
          [`select-${index}`]: index
        });

        return (
          <li
            className={optionsClasses}
            key={index}
            onClick={() => handleOptionClick(item.value, isSelected)}
          >
            {children || (item.label ? item.label : value)}
            {multiple && isSelected && <Icon icon={'check'} />}
          </li>
        );
      });
    } else {
      return React.Children.map(children, (child, i) => {
        const childElement =
          child as FunctionComponentElement<ISelectOptionProps>;
        if (childElement.type.displayName === 'Option') {
          return React.cloneElement(childElement, {
            index: `select-${i}`
          });
        } else {
          console.error(
            'Warning: Select has a child which is not a Option component'
          );
        }
      });
    }
  };

  return (
    <div className={containerClass} ref={containerRef}>
      <div className="tui-select-input" onClick={handleClick}>
        <Input
          value={value}
          ref={input}
          placeholder={placeholder}
          disabled={disabled}
          readOnly
          icon="arrow-down"
          name={name}
        />
      </div>

      <SelectContext.Provider value={passedContext}>
        <Transition in={menuOpen} animation="zoom-in-top" timeout={300}>
          <ul className="tui-select-dropdown">{generateOptions()}</ul>
        </Transition>
      </SelectContext.Provider>

      {multiple && (
        <div
          className="tui-selected-tags"
          style={{ maxWidth: containerWidth.current - 32 }}
        >
          {selectedValues.map((value, index) => {
            return (
              <span className="tui-tag" key={`tag-${index}`}>
                {value}
                <Icon
                  icon={'times'}
                  onClick={() => handleOptionClick(value, true)}
                />
              </span>
            );
          })}
        </div>
      )}
    </div>
  );
};

Select.defaultProps = {
  name: 'tui-select',
  placeholder: '请选择'
};

export default Select;

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