/*
	MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const RuntimeModule = require("../RuntimeModule");
const Template = require("../Template");

class OnChunksLoadedRuntimeModule extends RuntimeModule {
	constructor() {
		super("chunk loaded");
	}

	/**
	 * @returns {string} runtime code
	 */
	generate() {
		const { compilation } = this;
		const { runtimeTemplate } = compilation;
		return Template.asString([
			"var deferred = [];",
			`${
				RuntimeGlobals.onChunksLoaded
			} = ${runtimeTemplate.basicFunction("result, chunkIds, fn, priority", [
				"if(chunkIds) {",
				Template.indent([
					"priority = priority || 0;",
					"for(var i = deferred.length; i > 0 && deferred[i - 1][2] > priority; i--) deferred[i] = deferred[i - 1];",
					"deferred[i] = [chunkIds, fn, priority];",
					"return;"
				]),
				"}",
				"var notFulfilled = Infinity;",
				"for (var i = 0; i < deferred.length; i++) {",
				Template.indent([
					runtimeTemplate.destructureArray(
						["chunkIds", "fn", "priority"],
						"deferred[i]"
					),
					"var fulfilled = true;",
					"for (var j = 0; j < chunkIds.length; j++) {",
					Template.indent([
						`if ((priority & 1 === 0 || notFulfilled >= priority) && Object.keys(${
							RuntimeGlobals.onChunksLoaded
						}).every(${runtimeTemplate.returningFunction(
							`${RuntimeGlobals.onChunksLoaded}[key](chunkIds[j])`,
							"key"
						)})) {`,
						Template.indent(["chunkIds.splice(j--, 1);"]),
						"} else {",
						Template.indent([
							"fulfilled = false;",
							"if(priority < notFulfilled) notFulfilled = priority;"
						]),
						"}"
					]),
					"}",
					"if(fulfilled) {",
					Template.indent(["deferred.splice(i--, 1)", "result = fn();"]),
					"}"
				]),
				"}",
				"return result;"
			])};`
		]);
	}
}

module.exports = OnChunksLoadedRuntimeModule;