8pack.js

const
    assert = require("assert")
    , argv = require("minimist")(process.argv.slice(2))
    , fs = require("fs")
    , path = require("path")
    , {getVersion} = require("./src/versions")
    , writeOutput = (path, src) => {
        fs.writeFileSync(path, src);
        console.log("writing " + path);
    }
    , readmodules = require("./src/readmodules")
;

if (!argv._.length) {
    console.warn("missing mandatory arguments");
    //show man page
    console.log(require("./src/help"));
    process.exit(0);
}

if (argv.h || argv.help) {
    //show man page
    console.log(require("./src/help"));
    process.exit(0);
}

assert(argv._.length <= 2, "too many arguments");

const input = path.resolve(argv._[0]);  //use input path from arguments
assert.ok(input, "missing mandatory argument 'input'"); //throw when missing input
assert.doesNotThrow(() => fs.existsSync(input), `couldn't locate input file under ${input}`);

const output = argv._[1]; //use output from arguments
if (output) {
    assert.doesNotThrow(() => fs.existsSync(output), `couldn't locate output file under ${output}`);
}

const watch = argv.w || argv.watch;
const template = argv.t || argv.template;
console.log("using template", template);

//read from input path
const fileInputPath = path.resolve(input);
console.log("reading " + fileInputPath);

//inject input to inject path
const fileInjectPath = output ? path.resolve(output) : getVersion(template); //use specified file from output argument or template

//output the result to output path
const fileOutputPath = output ? path.resolve(output) : fileInputPath + ".p8"; //create a new file when not specified the output
console.log(`using ${fileOutputPath} as output`);

//read input files, find & collect modules
readmodules(fileInputPath);

const picoSource = fs.readFileSync(fileInjectPath, "utf8"); //contents of output file

const src = [
    picoSource.slice(0, picoSource.indexOf("__lua__") + 7),
    readmodules.convertInjects(),
    picoSource.slice(picoSource.indexOf("__gfx__")),
]
    .join("\n");

if (watch) {
    console.log("watching for file changes on " + fileInputPath);
    fs.watch(fileInputPath, {encoding: "buffer"}, (eventType, filename) => {
        if (filename && eventType === "change") {
            console.log("changes detected on " + filename.toString());
            writeOutput(fileOutputPath, src);
        }
    });
}
else {
    writeOutput(fileOutputPath, src);
    console.log("done");
    process.exit(0);
}