import type { Accessor, JSX } from 'solid-js';
import {
  createComponent,
  createContext,
  createMemo,
  createSignal,
  untrack,
  useContext,
} from 'solid-js';
import assert from '../utils/assert';

export interface CheckStateControlledOptions {
  checked: boolean | undefined;
  disabled?: boolean;
  onChange?: (state?: boolean) => void;
}

export interface CheckStateUncontrolledOptions {
  defaultChecked: boolean | undefined;
  disabled?: boolean;
  onChange?: (state?: boolean) => void;
}

export type CheckStateOptions = CheckStateControlledOptions | CheckStateUncontrolledOptions;

export interface CheckStateProperties {
  checked: () => boolean | undefined;
  setState: (newState?: boolean) => void;
  disabled: () => boolean;
  check: () => void;
  uncheck: () => void;
  reset: () => void;
  toggle: () => void;
}

/**
 * Creates a tri-state checkbox value: `true`, `false`, or `undefined` for
 * indeterminate. Backs `Checkbox`.
 *
 * Pass `defaultChecked` for uncontrolled state or `checked` for controlled.
 *
 * @see {@link https://github.com/lxsmnsyc/terracotta/blob/main/docs/states.md#check-state}
 */
export function createCheckState(options: CheckStateOptions): CheckStateProperties {
  // Reference to the signal read
  let signal: Accessor<boolean | undefined>;
  // Reference to the signal write
  let setSignal: (value: boolean | undefined) => void;

  // Type branding
  // Check if state is uncontrolled
  if ('defaultChecked' in options) {
    // Uncontrolled toggle means the toggle
    // manages its own state.
    const [isOpen, setIsOpen] = createSignal<boolean | undefined>(options.defaultChecked);
    signal = isOpen;
    setSignal = (value): void => {
      setIsOpen(value);
      if (options.onChange) {
        options.onChange(value);
      }
    };
  } else {
    // Controlled means relying on 3P state
    signal = createMemo(() => options.checked);
    setSignal = (value): void => {
      if (options.onChange) {
        options.onChange(value);
      }
    };
  }

  const isDisabled = createMemo(() => !!options.disabled);

  return {
    checked(): boolean | undefined {
      return signal();
    },
    setState(value): void {
      if (!untrack(isDisabled)) {
        setSignal(value);
      }
    },
    disabled: isDisabled,
    check(): void {
      if (!untrack(isDisabled)) {
        setSignal(true);
      }
    },
    uncheck(): void {
      if (!untrack(isDisabled)) {
        setSignal(false);
      }
    },
    reset(): void {
      if (!untrack(isDisabled)) {
        setSignal(undefined);
      }
    },
    toggle(): void {
      if (!untrack(isDisabled)) {
        setSignal(!untrack(signal));
      }
    },
  };
}

export interface CheckStateRenderProps {
  children?: JSX.Element | ((state: CheckStateProperties) => JSX.Element);
}

export interface CheckStateProviderProps extends CheckStateRenderProps {
  state: CheckStateProperties;
}

const CheckStateContext = createContext<CheckStateProperties>();

export function CheckStateProvider(props: CheckStateProviderProps): JSX.Element {
  return createComponent(CheckStateContext.Provider, {
    value: props.state,
    get children() {
      const current = props.children;
      if (typeof current === 'function') {
        return current(props.state);
      }
      return current;
    },
  });
}

/**
 * Reads the nearest check state from context. Throws when there is none.
 *
 * @see {@link https://github.com/lxsmnsyc/terracotta/blob/main/docs/states.md#check-state}
 */
export function useCheckState(): CheckStateProperties {
  const ctx = useContext(CheckStateContext);
  assert(ctx, new Error('Missing <CheckStateProvider>'));
  return ctx;
}

/**
 * Passes the nearest check state to a render prop. A function child is treated
 * as a render prop only when it declares exactly one parameter.
 *
 * @see {@link https://github.com/lxsmnsyc/terracotta/blob/main/docs/states.md#check-state}
 */
export function CheckStateChild(props: CheckStateRenderProps): JSX.Element {
  const state = useCheckState();
  return createMemo(() => {
    const current = props.children;
    if (typeof current === 'function' && current.length === 1) {
      return createMemo(() => current(state));
    }
    return current;
  }) as unknown as JSX.Element;
}