import { dasherize } from './util.strings';
import _ from 'underscore';

function BEMify(...bemObjectArray) {
	const scopeSet = new Set();
	const stateSet = new Set();
	const bemObjectSet = new Set(bemObjectArray.map(({ scope = '', block = '', element = '', modifier = '', state = '' }) => {
		if (scope) { scopeSet.add(dasherize(scope)); }
		if (state) { stateSet.add(`is-${dasherize(state)}`); }

		return [
			(block ? ` ${dasherize(block)}` : ''),
			(element ? `__${dasherize(element)}` : ''),
			(modifier ? `--${dasherize(modifier)}` : '')
		].join('');
	}));

	return `${Array.from(scopeSet).join(' ')} ${Array.from(bemObjectSet).join('')} ${Array.from(stateSet).join(' ')}`.trim();
}

function BEMifyFlatObject(...bemObjects) {
	// this can take an abutrary amount of flattened bem objects (or normal ones) and turn them into a bem string
	// { block: 'block1', element: 'elem1', block2: 'block2', modifier2: 'mod2', element3: 'elem' } => 'block__elem1 block2--mod2__elem'
	const RE_KEYNAME = 1;
	const RE_INDEX = 2;
	const bemArray = _.flatten(_.flatten(bemObjects, true).map((bemObject) => {
		const sortedBem = {};
		for (const keyName in bemObject) {
			// match key name patterns of a-zA-Z + number
			// block1 => block, 1
			// block => block, null
			const regexMatch = /(\D+)(\d{0,})/g.exec(keyName);

			// assume 0 index if no index is defined in keyname
			let targetKeyName = keyName;
			let targetIndex = 0;
			let targetValue = bemObject[keyName];

			// if regex match fails, then we'll just add whatever
			// that key was to the first index object
			if (regexMatch !== null) {
				targetKeyName = regexMatch[RE_KEYNAME];
				// if no number is matched then we will just
				// place it in the first index object
				targetIndex = regexMatch[RE_INDEX] || 0;
			}

			let index = parseInt(targetIndex);
			if (targetKeyName && Number.isFinite(index) && index >= 0) {
				if (sortedBem[index] === undefined) {
					sortedBem[index] = {};
				}

				Object.assign(sortedBem[index], {
					[targetKeyName]: targetValue
				});
			}
		}

		return _.toArray(sortedBem);
	}), true);

	return BEMify(...bemArray);
}

export default BEMifyFlatObject;