import { getCourseId } from "./utils-ENV.js";

const DB_TEMPLATE_LIST_HEADER = `
<table class="table table-striped">
  <thead>
    <tr>
      <th>Json</th>
    </tr>
  </thead>
  <tbody>
`;
const DB_TEMPLATE_LIST_ENTRY = `
<tr class="db-row">
  <td class="db-cell" data-key="date">##timeadded##</td>
  <td class="db-cell" data-key="coach">##user##</td>
  <td class="db-cell" data-key="json">[[Json]]</td>
</tr>
`;
const DB_TEMPLATE_LIST_FOOTER = `
 </tbody>
</table>
`;

let studentDbs = populateStudentDbs();

const ID_QUERY_PARAM_REGEX = /[?&]id=(\d+)/

async function populateStudentDbs() {
	const courseUrl = `https://lernplattform.bycs.de/course/view.php?id=${getCourseId()}`;
	const courseRes = await fetch(courseUrl);
	const courseDoc = new DOMParser().parseFromString(await courseRes.text(), 'text/html');

	let dbs = new Map();
	for (const link of courseDoc.querySelectorAll("div.activityname a.aalink")) {
		if (link.textContent.trim() === "Submit  Datenbank") {
			const dbId = link.href.match(ID_QUERY_PARAM_REGEX)[1]
			dbs.set("submit", new DB(dbId));
			continue;
		}

		const match = link.textContent.match(/(\d+)(Shadow|Public|Submit)/);
		if (!match) continue;
		const studentId = match[1];
		const dbType = match[2];
		const dbId = link.href.match(ID_QUERY_PARAM_REGEX)[1]

		if (!dbs.has(studentId)) {
			dbs.set(studentId, {});
		}

		dbs.get(studentId)[dbType.toLowerCase()] = new DB(dbId);
	}

	return dbs;
}

async function getSubmitDb() {
	const dbs = await studentDbs;
	return dbs.get("submit");
}

class DB {
	constructor(id) {
		this.id = id;
	}

	async fetchEntries(params) {
		return loadFromDatabaseActivity(this.id, params)
	}

	async saveEntry(json) {
		return addEntryToDatabaseActivity(this.id, json);
	}

	static async getStudentDbs(student) {
		const dbs = await studentDbs;
		return dbs.get(student.id);
	}
}

async function loadFromDatabaseActivity(id, params) {
	let dbUrl = `${window.location.origin}/mod/data/view.php?id=${id}&mode=list&perpage=1000`;
	// TODO(muhq): Why does this not include entries?
	if (params) {
		dbUrl += "&filter=1&advanced=1";
		for (const param in params) {
			dbUrl += `&${param}=${encodeURIComponent(params[param])}`
		}
	}

	const dbRes = await fetch(encodeURI(dbUrl));
	const dbDoc = new DOMParser().parseFromString(await dbRes.text(), 'text/html');
	let data = [];
	dbDoc.querySelectorAll('.db-row').forEach(row => {
		let entry = {};
		row.querySelectorAll('.db-cell').forEach(field => {
			const key = field.dataset.key;
			let value;
			// Moodle includes the full date in the title attribute of the included span
			if (key === "date") {
				value = field.querySelector("span").title;
			} else {
				value = field.innerText.trim();
			}
			entry[key] = value;
		});
		data.push(entry);
	});
	return data;
}

async function loadFromStudentDatabase(student, type) {
	const dbs = await DB.getStudentDbs(student);
	const db = dbs[type];
	return await db.fetchEntries()
}

async function addEntryToDatabaseActivity(id, json) {
	const url = `/mod/data/edit.php?id=${id}`;
	const editRes = await fetch(url);
	const editDoc = new DOMParser().parseFromString(await editRes.text(), 'text/html');
	const form = editDoc.querySelector('div[role="main"] > form');

	const formData = new FormData(form);

	for (const key of formData.keys()) {
		if (key.startsWith("field_")) {
			formData.set(key, json);
			// We found our json key
			break;
		}
	}
	formData.set("saveandview", "Speichern");

	return await fetch("/mod/data/edit.php", {
		method: "POST",
		// Set the FormData instance as the request body
		body: formData,
	});
}

async function addEntryToStudentDatabase(student, type, json) {
	let db;
	// global submit database
	if (type === "submit") {
		db = await getSubmitDb();
	// individuell databases
	} else {
		const dbs = await DB.getStudentDbs(student);
		db = dbs[type];
	}
	await db.saveEntry(json);
}

export {
	DB,
	getSubmitDb,
	loadFromDatabaseActivity, loadFromStudentDatabase,
	addEntryToDatabaseActivity, addEntryToStudentDatabase,
};