"use strict";

const kahn = require("./kahn");

module.exports = function sortDependencies(items) {
	let dependencyMap = new Map();
	let nodeMap = new Map();
	
	// The below code 1) inverts child-specifying nodes to parent-specifying nodes, and 2) ensures that nodes reference in-memory objects rather than IDs, so they work with the implementation of Kahn's algorithm. TODO: This should probably be made nicer at some point...

	items.forEach((item) => {
		dependencyMap.set(item.id, item);
		nodeMap.set(item.id, { id: item.id, children: [] });
	});

	items.forEach((item) => {
		Object.values(item.deps)
			.filter((dep => dep !== item.id))
			.forEach((dep) => {
				nodeMap.get(dep).children.push(nodeMap.get(item.id));
			});

		nodeMap.get(item.id).parents = Object.values(item.deps)
			.filter((id => id !== item.id))
			.map((id) => nodeMap.get(id));
	});
	
	let sortedNodes = kahn(Array.from(nodeMap.values()));
	
	return sortedNodes.map((node) => {
		return dependencyMap.get(node.id);
	});
};