import { ACCESS_TOKEN, SERVER_URL, SOURCE_ROOM_ID, TARGET_ROOM_ID } from "./conf.js";
import {readFileSync, writeFileSync} from "fs";


async function fetchMatrix(url, options = {}) {
	options.headers ||= {};
	options.headers.Authorization ||= `Bearer ${ACCESS_TOKEN}`;
	url = SERVER_URL + url;
	while (true) {
		console.debug("fetch", url);
		try {
			var res = await fetch(url, options);
			if (res.status == 429) {
				var {retry_after_ms} = await res.json();
			} else break;
		} catch (error) {
			console.error(error);
		}
		await new Promise(r => setTimeout(r, retry_after_ms || 60000));
	}
	if (!res.ok) throw new Error(`HTTP ${res.status} ${await res.text()}`);
	return res;
}

async function getMatrixEvents(room_id, until_event_id) {
	var events = [];
	do {
		var url = `/_matrix/client/v3/rooms/${encodeURIComponent(room_id)}/messages?dir=b&limit=50`;//use 1000 for initial fill
		if (end) url += `&from=${end}`;
		var {chunk, end} = await fetchMatrix(url).then(res => res.json());
		console.log(`got ${chunk.length}`);
		for (let event of chunk) {
			if (until_event_id && event.event_id == until_event_id) return events;
			events.push(event);
		}
	} while (end)
	return events;
}

async function getNewMatrixEvents(room_id) {
	var fn = `last_event_id_${room_id.replace(/[^\w]/g,'')}`;
	try {
		var last_event_id = readFileSync(fn, "utf8");
	} catch (error) {
		console.log(error.message);
	}
	var events = await getMatrixEvents(room_id, last_event_id);
	for (let event of events) {
		event.hasBeenProcessed = () => writeFileSync(fn, event.event_id);
	}
	return events;
}



var events = await getNewMatrixEvents(SOURCE_ROOM_ID);

for (let event of events.reverse()) {
	if (typeof event.content == "object" && ["m.video","m.audio","m.file"].includes(event.content.msgtype)) {
		let event_url = `https://matrix.to/#/${encodeURIComponent(event.room_id)}/${encodeURIComponent(event.event_id)}`;
		await fetchMatrix(`/_matrix/client/v3/rooms/${encodeURIComponent(TARGET_ROOM_ID)}/send/m.room.message/${Math.random()}`, {
			method: "PUT",
			headers: {"Content-Type": "application/json"},
			body: JSON.stringify({
				msgtype: event.content.msgtype,
				filename: event.content.filename || event.content.body,
				body: event_url,
				info: event.content.info,
				url: event.content.url
			})
		});
	}
	event.hasBeenProcessed();
}