change-bg.ts

#!/usr/bin/env -S deno --allow-run

import { decode } from "https://deno.land/std/strings/strings.ts";
import * as log from "https://deno.land/std/log/mod.ts";

function baseRandom(lower, upper) {
      return lower + Math.floor(Math.random() * (upper - lower + 1));
}

async function main() {
    // create subprocess
    const p = Deno.run({
        args: [
            "swaymsg",
            "-r",
            "-t",
            'get_outputs',
        ],
        stdout: "piped",
        stderr: "piped",
    });

    const outputs = JSON.parse(decode(await p.output()));

    if (!Array.isArray(outputs)) {
        console.log('outputs is no array');
        Deno.exit(1);
    }

    log.debug(`Detected ${outputs.length} outputs`);

    const bgProcess = Deno.run({
        args: [
            'find',
            '/home/tschumacher/datenknoten/cloud/bg',
            '-type',
            'f',
        ],
        stdout: "piped",
        stderr: "piped",
    });

    const images = decode(await bgProcess.output()).split('\n');

    log.debug(`Detected ${images.length} backgrounds`)

    for (const output of outputs) {
        const bg = images[baseRandom(0, images.length - 1)]
        const outputDevice = `"${output.make} ${output.model} ${output.serial}"`
        log.info(`Changing background to ${bg} on output ${outputDevice}`);
        const bgP = Deno.run({
            args: [
                'swaymsg',
                'output',
                outputDevice,
                'bg',
                bg,
                'fill',
            ],
            stdout: "piped",
            stderr: "piped",
        });

        await bgP.status();
    }


    Deno.exit(0);
}

main();