// TODO: refactor this mess

import { execFile as cpExecFile } from 'child_process';
import { createHash } from "crypto";
import { app, BrowserWindow, ipcMain, shell } from "electron";
import { createReadStream, mkdirSync, readFileSync, watch } from "fs";
import { open, readFile, writeFile } from "fs/promises";
import { join } from 'path';
import { promisify } from "util";
import { debounce } from "./utils/debounce";
import IpcEvents from './utils/IpcEvents';

const VENCORD_SRC_DIR = join(__dirname, "..");
const DATA_DIR = join(app.getPath("userData"), "..", "Vencord");
const SETTINGS_DIR = join(DATA_DIR, "settings");
const QUICKCSS_PATH = join(SETTINGS_DIR, "quickCss.css");
const SETTINGS_FILE = join(SETTINGS_DIR, "settings.json");

const execFile = promisify(cpExecFile);

mkdirSync(SETTINGS_DIR, { recursive: true });

async function calculateHashes() {
    const hashes = {} as Record<string, string>;

    await Promise.all(
        ["patcher.js", "preload.js", "renderer.js"].map(file => new Promise<void>(r => {
            const fis = createReadStream(join(__dirname, file));
            const hash = createHash("sha1", { encoding: "hex" });
            fis.once("end", () => {
                hash.end();
                hashes[file] = hash.read();
                r();
            });
            fis.pipe(hash);
        }))
    );

    return hashes;
}

function git(...args: string[]) {
    return execFile("git", args, {
        cwd: VENCORD_SRC_DIR
    });
}

function readCss() {
    return readFile(QUICKCSS_PATH, "utf-8").catch(() => "");
}

function readSettings() {
    try {
        return readFileSync(SETTINGS_FILE, "utf-8");
    } catch {
        return "{}";
    }
}

function serializeErrors(func: (...args: any[]) => any) {
    return async function () {
        try {
            return {
                ok: true,
                value: await func(...arguments)
            };
        } catch (e: any) {
            return {
                ok: false,
                error: e instanceof Error ? {
                    // prototypes get lost, so turn error into plain object
                    ...e
                } : e
            };
        }
    };
}

ipcMain.handle(IpcEvents.GET_SETTINGS_DIR, () => SETTINGS_DIR);
ipcMain.handle(IpcEvents.GET_QUICK_CSS, () => readCss());
ipcMain.handle(IpcEvents.OPEN_PATH, (_, ...pathElements) => shell.openPath(join(...pathElements)));
ipcMain.handle(IpcEvents.OPEN_EXTERNAL, (_, url) => shell.openExternal(url));

ipcMain.handle(IpcEvents.GET_UPDATES, serializeErrors(async () => {
    await git("fetch");

    const res = await git("log", `HEAD...origin/main`, "--pretty=format:%an/%h/%s");

    const commits = res.stdout.trim();
    return commits ? commits.split("\n").map(line => {
        const [author, hash, ...rest] = line.split("/");
        return {
            hash, author, message: rest.join("/")
        };
    }) : [];
}));

ipcMain.handle(IpcEvents.UPDATE, serializeErrors(async () => {
    const res = await git("pull");
    return res.stdout.includes("Fast-forward");
}));

ipcMain.handle(IpcEvents.BUILD, serializeErrors(async () => {
    const res = await execFile("node", ["build.mjs"], {
        cwd: VENCORD_SRC_DIR
    });
    return !res.stderr.includes("Build failed");
}));

ipcMain.handle(IpcEvents.GET_HASHES, serializeErrors(calculateHashes));

ipcMain.handle(IpcEvents.GET_REPO, serializeErrors(async () => {
    const res = await git("remote", "get-url", "origin");
    return res.stdout.trim()
        .replace(/git@(.+):/, "https://$1/")
        .replace(/\.git$/, "");
}));

// .on because we need Settings synchronously (ipcRenderer.sendSync)
ipcMain.on(IpcEvents.GET_SETTINGS, (e) => e.returnValue = readSettings());

// This is required because otherwise calling SET_SETTINGS in quick succession may lead to concurrent writes
let settingsWriteQueue = Promise.resolve();
ipcMain.handle(IpcEvents.SET_SETTINGS, (_, s) => {
    settingsWriteQueue = settingsWriteQueue.then(() => writeFile(SETTINGS_FILE, s));
});

export function initIpc(mainWindow: BrowserWindow) {
    open(QUICKCSS_PATH, "a+").then(fd => {
        fd.close();
        watch(QUICKCSS_PATH, debounce(async () => {
            mainWindow.webContents.postMessage(IpcEvents.QUICK_CSS_UPDATE, await readCss());
        }, 50));
    });
}