import * as Effect from "effect/Effect";
export const encode = (bytes: Uint8Array) =>
  btoa(String.fromCharCode(...bytes))
    .replaceAll("+", "-")
    .replaceAll("/", "_")
    .replaceAll("=", "");
export const decode = (value: string) =>
  Uint8Array.from(atob(value.replaceAll("-", "+").replaceAll("_", "/")), (c) =>
    c.charCodeAt(0),
  );
export const random = () => encode(crypto.getRandomValues(new Uint8Array(32)));
export const hash = (value: string) =>
  Effect.promise(() =>
    crypto.subtle.digest("SHA-256", new TextEncoder().encode(value)),
  ).pipe(Effect.map((bytes) => encode(new Uint8Array(bytes))));
export const opaque = (value: unknown): value is string =>
  typeof value === "string" && /^[A-Za-z0-9_-]{43}$/.test(value);
function key(secret: string) {
  return Effect.gen(function* () {
    return yield* Effect.promise(() =>
      crypto.subtle.importKey("raw", decode(secret), "AES-GCM", false, [
        "encrypt",
        "decrypt",
      ]),
    );
  });
}
export function encrypt(secret: string, value: unknown, binding: string) {
  return Effect.gen(function* () {
    const iv = crypto.getRandomValues(new Uint8Array(12));
    const cryptoKey = yield* key(secret);
    const ciphertext = yield* Effect.promise(() =>
      crypto.subtle.encrypt(
        {
          name: "AES-GCM",
          iv,
          additionalData: new TextEncoder().encode(binding),
        },
        cryptoKey,
        new TextEncoder().encode(JSON.stringify(value)),
      ),
    );
    return { iv: encode(iv), ciphertext: encode(new Uint8Array(ciphertext)) };
  });
}
export function decrypt<T>(
  secret: string,
  sealed: { iv: string; ciphertext: string },
  binding: string,
) {
  return Effect.gen(function* () {
    const cryptoKey = yield* key(secret);
    const bytes = yield* Effect.promise(() =>
      crypto.subtle.decrypt(
        {
          name: "AES-GCM",
          iv: decode(sealed.iv),
          additionalData: new TextEncoder().encode(binding),
        },
        cryptoKey,
        decode(sealed.ciphertext),
      ),
    );
    return JSON.parse(new TextDecoder().decode(bytes)) as T;
  });
}