/*
	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
	Copyright (C) 2023 Spacebar and Spacebar Contributors
	
	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published
	by the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.
	
	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import readline from "readline";
import fs from "fs/promises";
import path from "path";

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});

export function enableAutoUpdate(opts: { checkInterval: number | boolean; packageJsonLink: string; path: string; downloadUrl: string; downloadType?: "zip" }) {
    if (!opts.checkInterval) return;
    const interval = 1000 * 60 * 60 * 24;
    if (typeof opts.checkInterval === "number") opts.checkInterval = 1000 * interval;

    const i = setInterval(async () => {
        const currentVersion = await getCurrentVersion(opts.path);
        const latestVersion = await getLatestVersion(opts.packageJsonLink);
        if (currentVersion !== latestVersion) {
            clearInterval(i);
            console.log(`[Auto Update] Current version (${currentVersion}) is out of date, updating ...`);
            await download(opts.downloadUrl, opts.path);
        }
    }, interval);
    setImmediate(async () => {
        const currentVersion = await getCurrentVersion(opts.path);
        const latestVersion = await getLatestVersion(opts.packageJsonLink);
        if (currentVersion !== latestVersion) {
            rl.question(`[Auto Update] Current version (${currentVersion}) is out of date, would you like to update? (Y/n)`, (answer) => {
                if (answer === "" || answer.toLowerCase() === "y") {
                    console.log(`[Auto update] updating ...`);
                    download(opts.downloadUrl, opts.path);
                } else {
                    console.log(`[Auto update] aborted`);
                }
            });
        }
    });
}

async function download(url: string, dir: string) {
    try {
        // TODO: use file stream instead of buffer (to prevent crash because of high memory usage for big files)
        // TODO check file hash
        const response = await fetch(url);
        const buffer = await response.bytes();
        const tempDir = await fs.mkdtemp("spacebar");
        await fs.writeFile(path.join(tempDir, "Spacebar.zip"), buffer);
    } catch (error) {
        console.error(`[Auto Update] download failed`, error);
    }
}

async function getCurrentVersion(dir: string) {
    try {
        const content = await fs.readFile(path.join(dir, "package.json"), {
            encoding: "utf8",
        });
        return JSON.parse(content).version;
    } catch (error) {
        throw new Error("[Auto update] couldn't get current version in " + dir);
    }
}

async function getLatestVersion(url: string) {
    try {
        const response = await fetch(url);
        const content = (await response.json()) as { version: string };
        return content.version;
    } catch (error) {
        throw new Error("[Auto update] check failed for " + url);
    }
}