import { getUserIconUrl, getCourseParticipantsUrl } from "./config.js";
import { fetchGraduation } from "./graduation-common.js";
/**
 * Class to represent Students.
 */
class Student {
	graduation = null;

	constructor(id, name, groups) {
		this.id = id;
		this.name = name;
		this.groups = groups;
	}

	async getIconUrl() {
		return await getUserIconUrl(this.id);
	}

	getGroupName() {
		return `g${this.id}${this.name.replace(' ', '')}`;
	}

	getRealGroups() {
		if(typeof this.groups === "string") {
			return [this.groups];
		}
		return this.groups.filter((g) => g !== this.getGroupName());
	}

	async getGraduation() {
		if(!this.graduation) {
			// fetchGraduation(this) sets this.graduation
			await fetchGraduation(this);
		}
		return this.graduation;
	}
}

async function fetchStudent(idFilter, nameFilter, groupFilter) {
	const students = await fetchStudents(idFilter, nameFilter, groupFilter);
	return students[0];
}

// Cache the fetched students.
let students = [];

const idRegex = /id=(\d+)/;
async function fetchStudents(idFilter, nameFilter, groupFilter) {
	if (students.size) {
		return students;
	}

	const res = await fetch(getCourseParticipantsUrl());
	const doc = new DOMParser().parseFromString(await res.text(), "text/html");
	const table = doc.querySelector("tbody");
	table.querySelectorAll("tr").forEach(row => {
		if (row.classList.contains("emptyrow"))
			return;

		const roleCell = row.querySelector(".c4");
		// TODO(muhq): Is this locale dependent?
		if (roleCell.innerHTML.includes("Lehrer")) {
			return;
		}

		const nameCell = row.querySelector(".c1");
		let name;
		if (nameCell.firstChild.firstChild.tagName == "SPAN")
			name = nameCell.firstChild.firstChild.title;
		else
			name = nameCell.innerText;

		const profileUrl = nameCell.querySelector("a.aabtn").href;
		const match = idRegex.exec(profileUrl);
		const id = match[1];

		const groupCell = row.querySelector(".c5");
		const groupsText = groupCell.querySelector("a.quickeditlink").textContent;
		const groups = groupsText.trim().split(", ");

		if ((!idFilter || id === idFilter) &&
			(!nameFilter || name.includes(nameFilter)) &&
			(!groupFilter || groups.filter((g) => g.includes(groupFilter))))
		{
			students.push(new Student(id, name, groups));
		}
	});
	return students;
}

export { Student, fetchStudents, fetchStudent };