feat: add basic impl

pkgs/server/package.json

@@ -0,0 +1,13 @@
+{
+	"name": "@pow-captcha/server",
+	"version": "0.0.0",
+	"module": "dist/lib.js",
+	"types": "dist/lib.d.ts",
+	"scripts": {
+		"build": "tsc -p tsconfig.build.json"
+	},
+	"dependencies": {
+		"@pow-captcha/solver": "workspace:*",
+		"@pow-captcha/shared": "workspace:*"
+	}
+}

pkgs/server/src/lib.ts

@@ -0,0 +1,88 @@
+import { utils, wire } from "@pow-captcha/shared";
+import * as solver from "@pow-captcha/solver";
+
+export type CreateChallengesOptions = {
+	/** @default 50 */
+	challengeCount?: number;
+	/** @default 16 */
+	challengeLength?: number;
+	/** @default 2 */
+	difficulty?: number;
+};
+
+export async function createChallenges(
+	{
+		challengeCount = 50,
+		challengeLength = 16,
+		difficulty = 2,
+	}: CreateChallengesOptions,
+	secret: string,
+): Promise<wire.SignedData> {
+	const challenges = utils.createArray(
+		challengeCount,
+		(): wire.ChallengeEntry => {
+			const challenge = new Uint8Array(challengeLength);
+			crypto.getRandomValues(challenge);
+
+			const target = new Uint8Array(difficulty);
+			crypto.getRandomValues(target);
+
+			return [
+				wire.serializeArray(challenge),
+				wire.serializeArray(target),
+			];
+		},
+	);
+
+	const challenge: wire.Challenge = {
+		magic: wire.CHALLENGE_MAGIC,
+		challenges,
+	};
+	return await wire.serializeAndSignData(challenge, secret);
+}
+
+export async function redeemChallengeSolution(
+	{ challengesSigned, solutions }: wire.ChallengeSolution,
+	secret: string,
+): Promise<wire.SignedData> {
+	const challengesWire = await wire.verifyAndDeserializeData(
+		challengesSigned,
+		wire.challengeSchema,
+		secret,
+	);
+
+	if (challengesWire.challenges.length !== solutions.length) {
+		throw new Error(
+			`Number of solutions does not match the number of challenges`,
+		);
+	}
+
+	const verifyTasks = challengesWire.challenges.map(async (challenge, i) => {
+		const solution = solutions[i]!;
+		const isValid = await solver.verify(
+			wire.deserializeArray(challenge[0]),
+			wire.deserializeArray(challenge[1]),
+			wire.deserializeArray(solution),
+		);
+		if (!isValid) {
+			throw new Error(`The solution with index ${i} is invalid`);
+		}
+	});
+	await Promise.all(verifyTasks);
+
+	const redeemed: wire.Redeemed = {
+		magic: wire.REDEEMED_MAGIC,
+	};
+	return await wire.serializeAndSignData(redeemed, secret);
+}
+
+export async function verifyRedeemed(
+	redeemedSigned: wire.SignedData,
+	secret: string,
+): Promise<void> {
+	await wire.verifyAndDeserializeData(
+		redeemedSigned,
+		wire.redeemedSchema,
+		secret,
+	);
+}

pkgs/server/tsconfig.build.json

@@ -0,0 +1,8 @@
+{
+	"extends": "../../tsconfig.build.json",
+	"compilerOptions": {
+		"outDir": "dist"
+	},
+	"include": ["src/**/*"],
+	"exclude": ["**/*.spec.ts"]
+}

pkgs/server/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"include": ["src/**/*"]
+}