import * as React from "react";

export const useMounted = () => {
  const isMounted = React.useRef(true);
  React.useLayoutEffect(() => {
    return () => {
      isMounted.current = false;
    };
  }, []);
  return isMounted.current;
};

/** NOTE(amine):
 * useForm handles three main responsabilities
 *  - control inputs
 *  - control form
 *  - add validations
 *
 *  For validations
 *  - Validate each field when onBlur event is triggered
 *  - Validate all fields before submit
 *  - font submit if there is errors
 */

export const useForm = ({
  onSubmit,
  validate,
  initialValues,
  validateOnBlur = true,
  validateOnSubmit = true,
}) => {
  const [internal, setInternal] = React.useState({ isSubmitting: false, isValidating: false });
  const [state, setState] = React.useState({
    isSubmitting: false,
    values: initialValues,
    errors: {},
    touched: {},
  });

  const _hasError = (obj) => Object.keys(obj).some((name) => obj[name]);
  const _mergeEventHandlers = (events = []) => (e) =>
    events.forEach((event) => {
      if (event) event(e);
    });

  /** ---------- NOTE(amine): Input Handlers ---------- */
  const handleFieldChange = (e) =>
    setState((prev) => ({
      ...prev,
      values: { ...prev.values, [e.target.name]: e.target.value },
      errors: { ...prev.errors, [e.target.name]: undefined },
      touched: { ...prev.touched, [e.target.name]: false },
    }));

  const handleOnBlur = async (e) => {
    // NOTE(amine): validate the inputs onBlur and touch the current input
    let errors = {};
    if (validateOnBlur && validate) {
      try {
        setInternal((prev) => ({ ...prev, isValidating: true }));
        errors = await validate(state.values, {});
      } catch (e) {
        console.log("validation", e);
      } finally {
        setInternal((prev) => ({ ...prev, isValidating: false }));
        setState((prev) => ({
          ...prev,
          touched: { ...prev.touched, [e.target.name]: validateOnBlur },
          errors,
        }));
      }
    }
  };

  // Note(Amine): this prop getter will capture the field state
  const getFieldProps = (name, { onChange, onBlur, error } = {}) => ({
    name: name,
    value: state.values[name],
    error: error || state.errors[name],
    touched: state.touched[name],
    onChange: _mergeEventHandlers([onChange, handleFieldChange]),
    onBlur: _mergeEventHandlers([onBlur, handleOnBlur]),
  });

  /** ---------- NOTE(amine): Form Handlers ----------  */

  const submitAsync = async () => {
    // NOTE(amine): Don't submit if the form is validating or already submitting
    if (internal.isSubmitting || internal.isValidating) return;

    //NOTE(amine): touch all inputs
    setState((prev) => {
      const touched = Object.keys(prev.values).reduce((acc, key) => ({ ...acc, [key]: true }), {});
      return { ...prev, touched };
    });

    // NOTE(amine): validate inputs
    if (validateOnSubmit && validate) {
      let errors = {};
      try {
        setInternal((prev) => ({ ...prev, isValidating: true }));
        errors = await validate(state.values, { ...state.errors });
        if (_hasError(errors)) return;
      } catch (e) {
        console.log("validation", e);
      } finally {
        setInternal((prev) => ({ ...prev, isValidating: false }));
        setState((prev) => ({ ...prev, errors }));
      }
    }

    // NOTE(amine): submit the form
    if (!onSubmit) return;
    setInternal((prev) => ({ ...prev, isSubmitting: true }));
    try {
      await onSubmit(state.values);
    } catch (e) {
      console.log("submitting", e);
    } finally {
      setInternal((prev) => ({ ...prev, isSubmitting: false }));
    }
  };

  const handleFormOnSubmit = (e) => {
    e.preventDefault();
    submitAsync()
      .then()
      .catch((e) => console.log(e));
  };

  // Note(Amine): this prop getter will overide the form onSubmit handler
  const getFormProps = () => ({
    onSubmit: handleFormOnSubmit,
  });

  return {
    getFieldProps,
    getFormProps,
    values: state.values,
    isSubmitting: internal.isSubmitting,
    isValidating: internal.isValidating,
  };
};

/** NOTE(amine): Since we can use on our design system an input onSubmit,
 *               useField is a special case of useForm
 */
export const useField = ({
  onSubmit,
  validate,
  initialValue,
  onChange,
  onBlur,
  validateOnBlur = true,
  validateOnSubmit = true,
}) => {
  const [state, setState] = React.useState({
    isSubmitting: false,
    value: initialValue,
    error: undefined,
    touched: undefined,
  });

  const _mergeEventHandlers = (events = []) => (e) =>
    events.forEach((event) => {
      if (event) event(e);
    });

  /** ---------- NOTE(amine): Input Handlers ---------- */
  const handleFieldChange = (e) =>
    setState((prev) => ({
      ...prev,
      value: e.target.value,
      error: undefined,
      touched: false,
    }));

  const handleOnBlur = (e) => {
    // NOTE(amine): validate the inputs onBlur and touch the current input
    let error = {};
    if (validateOnBlur && validate) error = validate(state.value);
    setState((prev) => ({ ...prev, touched: validateOnBlur, error }));
  };

  const handleFormOnSubmit = (e) => {
    //NOTE(amine): touch all inputs
    setState((prev) => ({ ...prev, touched: true }));

    // NOTE(amine): validate inputs
    if (validateOnSubmit && validate) {
      const error = validate(state.value);
      setState((prev) => ({ ...prev, error }));
      if (error) return;
    }

    // NOTE(amine): submit the form
    if (!onSubmit) return;
    setState((prev) => ({ ...prev, isSubmitting: true }));
    onSubmit(state.value)
      .then(() => {
        setState((prev) => ({ ...prev, isSubmitting: false }));
      })
      .catch(() => {
        setState((prev) => ({ ...prev, isSubmitting: false }));
      });
  };

  // Note(Amine): this prop getter will capture the field state
  const getFieldProps = (name) => ({
    name: name,
    value: state.value,
    error: state.error,
    touched: state.touched,
    onChange: _mergeEventHandlers([onChange, handleFieldChange]),
    onBlur: _mergeEventHandlers([onBlur, handleOnBlur]),
    onSubmit: handleFormOnSubmit,
  });

  return { getFieldProps, value: state.value, isSubmitting: state.isSubmitting };
};