// Some standard utility functions for Dyynaform consumers

import { ValueTransformer } from './interfaces';

// Dropdown Modified Input - Starts With / Contains / Matches
const standardModifiers = ['Starts with', 'Contains', 'Matches'];
const standardTransformer: ValueTransformer = {
	inputFn: val => {
		let modifier = 'Starts with';
		if (/^%.*?%$/.test(val)) {
			modifier = 'Contains'
		} else if (/^[^%].*?[^%]$/.test(val)) {
			modifier = 'Matches'
		} else if (/^%.*/.test(val)) {
			modifier = 'Starts with';
		}
		const transformedVal = val.replace(/%/g, '').trim();
		return { modifier: modifier, value: transformedVal };
	},
	outputFn: (mod, val) => {
		let transformedValue;
		switch(mod) {
			case 'Starts with':
				transformedValue = `%${val}`;
				break;
			case 'Contains':
				transformedValue = `%${val}%`;
				break;
			case 'Matches':
			default:
				transformedValue = val;
				break;
		}
		return transformedValue;
	}
};

// Generate array from CSV string
const toArrTag = (str: TemplateStringsArray): string[] => str[0].split(',').map(key => key.trim());

// Pad array
const arrayPad = (length: number) => (arr: string[]): any[] => [...arr, ...Array(length - arr.length).fill('')];

// Utility function for casting an array to metadata (useful for components that render FormGroups)
const arrayToMeta = array => array.map(val => ({ name: val, 'value' : val }));

// Exclude 'fieldsToExclude' from obj, returning a new object
// fieldsToExclude can be an array of field keys or a CSV of field keys
const excludeFields = (obj: StringMap, fieldsToExclude: string | string[]) => {
	const ex = Array.isArray(fieldsToExclude) ? fieldsToExclude : fieldsToExclude.split(',').map(key => key.trim());
	return Object.entries(obj).reduce(
		(res, [key, val]) => ex.includes(key) ? res : { ...res, [key]: val },
		{}
	);
}

export { standardModifiers, standardTransformer, toArrTag, arrayPad, arrayToMeta, excludeFields };