export function build(dictionaryString) {
}

export function buildTreeStruct(monoLineString) {
	//console.log('srcTree', monoLineString);
	const stringAsArray = monoLineString.split('');
	const rawTree = leftParser(stringAsArray);
	//console.log('rawTree', JSON.stringify(rawTree));
	const outOfScope = stringAsArray.length;
	if (outOfScope) throw `fail to build tree from : "${monoLineString}" parsed: ${JSON.stringify(rawTree)} unparsed/failed: ${stringAsArray.join('')}`;
	//return rawTree;//trivialDedup(flattenTree(rawTree))
	return flattenTree(flattenTree(flattenTree(rawTree)));
}

/**
 * leftParser stuff
 */
function flushNoEmptyString(data) {
	if (data.str.length) data.tree[data.tree.length - 1].step.push(data.str);
	data.str = '';
}

function appendToString(chr, data) {
	data.str += chr;
}

function nextAlt(data) {
	data.tree.push({step: []});
}

function goIntoNewAlt(data) {
	data.tree[data.tree.length - 1].step.push(leftParser(data.input));
}

function returnTrue() {
	return true;
}

function doTheses() {
}

const leftParserFunc = {
	')': (chr, data) => returnTrue(flushNoEmptyString(data)),
	'|': (chr, data) => doTheses(flushNoEmptyString(data), nextAlt(data)),
	'(': (chr, data) => doTheses(flushNoEmptyString(data), goIntoNewAlt(data)),
	'default': (chr, data) => appendToString(chr, data)
}

function leftParser(inputChrArray) {
	const data = {
		input: inputChrArray,
		str: '',
		tree: [{step: []}],
	};
	while (data.input.length) {
		const chr = data.input.shift();
		if (typeof leftParserFunc[chr] !== 'undefined') {
			const out = leftParserFunc[chr](chr, data);
			if (out) return data.tree;
		} else leftParserFunc['default'](chr, data);
	}
	flushNoEmptyString(data);
	return data.tree;
}

// end leftParser
function concatStrings(array) {
	const data = {
		input: array,
		str: '',
		tree: [{step: []}],
	};
	array.forEach(e => {
		if (typeof e === 'string') appendToString(e, data);
		else {
			flushNoEmptyString(data)
			data.tree[data.tree.length - 1].step.push(e);
		}
	});
	flushNoEmptyString(data)
	return data.tree[data.tree.length - 1].step;
}

function flattenTree(tree) {
	if (typeof tree === 'string') return tree;
	if (Array.isArray(tree) && tree.length === 0) return '';
	if (Array.isArray(tree) && tree.length === 1) return flattenTree(tree[0]);
	if (isStep(tree)) {
		tree.step = tree.step.map(flattenTree);
		if (!Array.isArray(tree.step)) return flattenTree(tree.step);
		if (tree.step.length === 1) return flattenTree(tree.step);
		if (tree.step.length === 0) return '';
		if (!tree.step.reduce((acc, cur) => Array.isArray(cur) || acc, false)) return concatStrings(tree.step);
		return tree;
	}

	if (tree.length === 1) {
		//console.log('aloneChild', JSON.stringify(tree[0]));
		if (typeof tree[0] === 'string') return tree[0];
		if (Array.isArray(tree[0])) return flattenTree(tree[0]);
		//return flattenTree(tree[0].step);
	}

	if (!Array.isArray(tree)) throw `Error : ${tree} should be an Array. ${JSON.stringify(tree)}`;
	//console.log('tree:', JSON.stringify(tree));
	///if(isStep(tree[0])) tree[0].step = flattenTree(tree[0].step);
	tree = trivialDedup(tree.map(flattenTree));
	tree = [].concat(...tree.map(e => Array.isArray(e) ? e : [e]));

	return tree;
}

function isStep(element) {
	return typeof element === 'object' && typeof element.step !== 'undefined';
}

function trivialDedup(tree) {
	if (typeof tree === 'string') return tree;
	if (isStep(tree)) return {step: tree.step.map(subTree => trivialDedup(subTree))};
	if (Array.isArray(tree)) {
		const dedupKeys = {};
		tree.forEach(v => dedupKeys[JSON.stringify(v)] = v); // eslint-disable-line no-return-assign
		return Object.keys(dedupKeys).map(json => trivialDedup(JSON.parse(json)));
	}
	throw `unknown case : ${tree}`;
}

export function serialize(treeStruct) {
	if (typeof treeStruct === 'string') return treeStruct;
	if (Array.isArray(treeStruct)) return `(${treeStruct.map(serialize).join('|')})`;
	if (isStep(treeStruct)) return treeStruct.step.map(serialize).join('');
	throw new Error(`Error: how to serialize ${JSON.stringify(treeStruct)} RAW: ${treeStruct}`);
}

/*
export function extract(treeNavArray,fromTreeWrapped){
	if(!Array.isArray(treeNavArray)) throw new Error(`treeNav: ${JSON.stringify(treeNavArray)} should be an integer array.`);
	let extractedTree = '';
	if(treeNavArray.length === 0) return fromTreeWrapped.pop();
	if (typeof fromTreeWrapped[0] === 'string') throw new Error(`invalid treeNav pointer ${JSON.stringify(treeNavArray)} in ${serialize(fromTreeWrapped[0])} no branch ${treeNavArray[0]}.`);
	if (Array.isArray(fromTreeWrapped[0])) {
		const branch = treeNavArray.shift();
		const extractedTree = fromTreeWrapped[0][branch]; // recursive here ?
		//fromTreeWrapped[0] = [].concat(branch>0?fromTreeWrapped[0].slice(0,branch-1):[],fromTreeWrapped[0].slice(branch+1,fromTreeWrapped[0].length));
		return extractedTree;
	}
	if (isStep(fromTreeWrapped[0])) {
		const extractedTree = {step:[]};
		fromTreeWrapped[0].step.forEach()

		f
	}


	return extractedTree;
}
*/