const fs = require("node:fs")
const path = require("node:path")
const crypto = require("node:crypto")

const SECRETS_DIR = path.join(process.cwd(), "data", "secrets")
const PRIVATE_KEY = path.join(SECRETS_DIR, "server.private.pem")
const PUBLIC_KEY = path.join(SECRETS_DIR, "server.public.pem")

function generateServerKeyPair() {
    const { privateKey, publicKey } = crypto.generateKeyPairSync("rsa", {
        modulusLength: 2048,
        publicKeyEncoding: {
            type: "spki",
            format: "pem",
        },
        privateKeyEncoding: {
            type: "pkcs8",
            format: "pem",
        },
    })

    return {
        privateKeyPem: privateKey,
        publicKeyPem: publicKey,
    }
}

function saveKeyPairToDisk({ publicKeyPem, privateKeyPem }) {
	fs.mkdirSync(SECRETS_DIR, { recursive: true })
	fs.writeFileSync(PRIVATE_KEY, privateKeyPem, { mode: 0o600 })
	fs.writeFileSync(PUBLIC_KEY, publicKeyPem, { mode: 0o644 })
}

function keyFilesExist() {
	return {
		privateExists: fs.existsSync(PRIVATE_KEY),
		publicExists: fs.existsSync(PUBLIC_KEY),
	}
}

function restorePublicKeyFile(publicKeyPem) {
	fs.mkdirSync(SECRETS_DIR, { recursive: true })
	fs.writeFileSync(PUBLIC_KEY, publicKeyPem, { mode: 0o644 })
}

function readPrivateKey() {
	return fs.readFileSync(PRIVATE_KEY, "utf8")
}

function readPublicKey() {
	return fs.readFileSync(PUBLIC_KEY, "utf8")
}

module.exports = {
    generateServerKeyPair,
    saveKeyPairToDisk,
    keyFilesExist,
    restorePublicKeyFile,
    readPrivateKey,
    readPublicKey
}