import { decodeJwt, importPKCS8, importSPKI, jwtVerify, SignJWT, type JWTPayload } from "jose";
import * as DateTime from "effect/DateTime";
import * as Effect from "effect/Effect";
import * as Schema from "effect/Schema";

export const RELAY_LINK_PROOF_TYP = "t3-env-link+jwt";
export const RELAY_MINT_REQUEST_TYP = "t3-cloud-mint+jwt";
export const RELAY_HEALTH_REQUEST_TYP = "t3-cloud-health+jwt";
export const RELAY_MINT_RESPONSE_TYP = "t3-env-mint+jwt";
export const RELAY_HEALTH_RESPONSE_TYP = "t3-env-health+jwt";
export const RELAY_ACTIVITY_PUBLISH_TYP = "t3-env-activity+jwt";

export class RelayJwtSignError extends Schema.TaggedErrorClass<RelayJwtSignError>()(
  "RelayJwtSignError",
  {
    typ: Schema.String,
    cause: Schema.Defect(),
  },
) {
  override get message(): string {
    return `Failed to sign relay JWT (${this.typ}).`;
  }
}

export class RelayJwtVerifyError extends Schema.TaggedErrorClass<RelayJwtVerifyError>()(
  "RelayJwtVerifyError",
  {
    typ: Schema.String,
    issuer: Schema.String,
    audience: Schema.String,
    cause: Schema.Defect(),
  },
) {
  override get message(): string {
    return `Failed to verify relay JWT (${this.typ}).`;
  }
}

export const RelayJwtError = Schema.Union([RelayJwtSignError, RelayJwtVerifyError]);
export type RelayJwtError = typeof RelayJwtError.Type;

export function normalizeRelayIssuer(value: string): string {
  return value.trim().replace(/\/+$/gu, "");
}

export function decodeRelayJwt(token: string): JWTPayload {
  return decodeJwt(token);
}

function normalizePem(value: string): string {
  return value.replace(/\\n/gu, "\n").trim();
}

export function signRelayJwt(input: {
  readonly privateKey: string;
  readonly typ: string;
  readonly payload: JWTPayload;
}): Effect.Effect<string, RelayJwtError> {
  return Effect.tryPromise({
    try: async () => {
      const key = await importPKCS8(normalizePem(input.privateKey), "EdDSA");
      return new SignJWT(input.payload)
        .setProtectedHeader({ alg: "EdDSA", typ: input.typ })
        .sign(key);
    },
    catch: (cause) => new RelayJwtSignError({ typ: input.typ, cause }),
  });
}

export function verifyRelayJwt(input: {
  readonly publicKey: string;
  readonly token: string;
  readonly typ: string;
  readonly issuer: string;
  readonly audience: string;
  readonly nowEpochSeconds: number;
}): Effect.Effect<JWTPayload, RelayJwtError> {
  return Effect.tryPromise({
    try: async () => {
      const key = await importSPKI(normalizePem(input.publicKey), "EdDSA");
      const verified = await jwtVerify(input.token, key, {
        algorithms: ["EdDSA"],
        typ: input.typ,
        issuer: input.issuer,
        audience: input.audience,
        maxTokenAge: "5 minutes",
        clockTolerance: 60,
        currentDate: DateTime.toDate(DateTime.makeUnsafe(input.nowEpochSeconds * 1_000)),
      });
      return verified.payload;
    },
    catch: (cause) =>
      new RelayJwtVerifyError({
        typ: input.typ,
        issuer: input.issuer,
        audience: input.audience,
        cause,
      }),
  });
}