const fs = require("fs")
const path = require("path")
const jsfiles = [...new Set(process.argv.slice(2))]

if(jsfiles.length === 0){
	throw new Error("no files")
} else {
	console.log(jsfiles)
}

const modules = []
for(const file of jsfiles){
	const abspath = path.resolve(file)
	const content = fs.readFileSync(abspath).toString()
	const key = new URL(abspath, "file:///")
	modules.push(`"${key}": ({require, module, exports}) => {${content}},`)
}

const entrypoint = new URL(path.resolve(jsfiles[0]), "file:///")

const output = `
const sources = {
${modules.join("\n")}
}
const cache = {}
const sym = Symbol()
const createRequire = file => reqpath => {
	const key = new URL(reqpath, file)
	if(key in cache){
		if(cache[key] === sym) throw new Error("Cyclic require is detected.")
		return cache[key]
	}
	cache[key] = sym
	const exports = {}
	const module = {exports}
	sources[key]({
		require: createRequire(key),
		module,
		exports,
	})
	cache[key] = module.exports
	return module.exports
}
const entrypoint = "${entrypoint}"
createRequire("file:///")(entrypoint)
`

fs.writeFileSync("./output.js", output)