import React, { useState, useCallback, useRef, useContext, useEffect } from 'react';
import { Caret } from '../assets/index';
import cx from 'classnames';
import useOnClickOutside from 'use-onclickoutside';

export type CurrentValue = {
  value: number;
  label: string;
};

type ContextValues = {
  open: boolean;
  disabled: boolean;
  fullwidth: boolean;
  current: CurrentValue | undefined;
  onChange: (value: CurrentValue) => void;
  toggleOpen: () => void;
};

type ItemProps = {
  label: string;
  value: number;
};

const DropdownContext = React.createContext<ContextValues>({
  open: false,
  fullwidth: false,
  disabled: false,
  current: undefined,
  onChange: () => {},
  toggleOpen: () => {},
});

const useDropdownContext = (): ContextValues => {
  const context = useContext(DropdownContext);
  if (!context) {
    throw new Error(`NOPE`);
  }
  return context;
};

const Item: React.FC<ItemProps> = ({ label, value }) => {
  const { onChange } = useDropdownContext();
  return (
    <a className="dropdown-item" onClick={(): void => onChange({ label, value })}>
      {label}
    </a>
  );
};

const Label: React.FC<{ valueDataTestid?: string }> = ({ children, valueDataTestid }) => {
  const { current, fullwidth, disabled } = useDropdownContext();
  return (
    <div className="dropdown-trigger">
      <button
        className={cx(['button', 'is-outlined', { 'is-fullwidth': fullwidth }])}
        aria-haspopup="true"
        aria-controls="dropdown-menu"
        type="button"
        disabled={disabled}
      >
        <span className={cx({ 'is-dimmed': !current })} data-testid={valueDataTestid}>
          {current ? current.label : children}
        </span>
        <span className={cx('icon is-small', { 'is-dimmed': !current })}>
          <Caret className={cx('caret--opened')} />
        </span>
      </button>
    </div>
  );
};

const Menu: React.FC = ({ children }) => {
  return (
    <div className="dropdown-menu" id="dropdown-menu" role="menu">
      <div className="dropdown-content">{children}</div>
    </div>
  );
};

type CompoundComponents = {
  Item: React.FC<ItemProps>;
  Menu: React.FC;
  Label: React.FC<{ valueDataTestid?: string }>;
};

type DropdownProps = {
  fullwidth: boolean;
  disabled: boolean;
  onChange: (value: number) => void;
  initial?: CurrentValue;
  dataTestid?: string;
  title?: string;
};

const Dropdown: React.FC<DropdownProps> & CompoundComponents = ({
  onChange,
  title,
  disabled,
  fullwidth,
  children,
  initial,
  dataTestid,
}) => {
  const [current, setCurrent] = useState<CurrentValue | undefined>(initial);
  const [open, setOpen] = useState(false);

  useEffect(() => {
    setCurrent(initial);
  }, [initial]);

  const handleChange = useCallback(
    ({ value, label }) => {
      if (!disabled) {
        setCurrent({ value, label });
        onChange && onChange(value);
      }
    },
    [disabled, onChange]
  );

  const toggleOpen = useCallback(() => {
    if (!disabled) {
      setOpen((open) => !open);
    }
  }, [disabled]);

  const node = useRef<HTMLHeadingElement>(null);

  useOnClickOutside(node, () => setOpen(false));

  return (
    <DropdownContext.Provider
      value={{
        open,
        fullwidth,
        disabled,
        current,
        onChange: handleChange,
        toggleOpen,
      }}
    >
      <div
        className={cx(['dropdown', open && 'is-active', { 'is-fullwidth': fullwidth }])}
        onClick={toggleOpen}
        ref={node}
        data-testid={dataTestid}
        title={title}
      >
        {children}
      </div>
    </DropdownContext.Provider>
  );
};

Dropdown.Item = Item;
Dropdown.Menu = Menu;
Dropdown.Label = Label;

export default Dropdown;