import { createSign, generateKeyPairSync } from "node:crypto";
import { expect, test } from "vitest";
import {
  createOidcProtocol,
  OidcIssuerMismatchError,
  OidcJwksUnavailableError,
  OidcProtocolError,
  OidcProviderUnavailableError,
} from "../src/auth/oidc-client.js";

const issuer = "https://issuer.example.test";
const clientId = "thothii";
const callbackUrl = "https://thothii.example.test/api/auth/oidc/callback";
const verifier = "v".repeat(43);
const nonce = "n".repeat(43);
const state = "s".repeat(43);

const keys = generateKeyPairSync("rsa", { modulusLength: 2048 });
const jwk = { ...keys.publicKey.export({ format: "jwk" }), kid: "test-key", use: "sig", alg: "RS256" };

function token(claims: Record<string, unknown>, invalidSignature = false): string {
  const encode = (value: unknown) => Buffer.from(JSON.stringify(value)).toString("base64url");
  const input = `${encode({ alg: "RS256", kid: "test-key", typ: "JWT" })}.${encode(claims)}`;
  const signer = createSign("RSA-SHA256");
  signer.update(input);
  signer.end();
  const signature = signer.sign(keys.privateKey).toString("base64url");
  const corruptedSignature = signature.startsWith("A") ? `B${signature.slice(1)}` : `A${signature.slice(1)}`;
  return `${input}.${invalidSignature ? corruptedSignature : signature}`;
}

function protocol(options: {
  claims?: Record<string, unknown>;
  discoveryIssuer?: string;
  invalidSignature?: boolean;
  seen?: URL[];
  discoveryResponse?: (init?: RequestInit) => Response | Promise<Response>;
  tokenResponse?: (init?: RequestInit) => Response | Promise<Response>;
  jwksResponse?: (init?: RequestInit) => Response | Promise<Response>;
  httpTimeoutMs?: number;
  jwksTimeoutMs?: number;
  discoveryMetadata?: Record<string, unknown>;
} = {}) {
  const now = Math.floor(Date.now() / 1000);
  const claims = {
    iss: issuer,
    sub: "user-123",
    aud: clientId,
    exp: now + 300,
    iat: now,
    nonce,
    name: "Ada Lovelace",
    groups: ["TOT Users", "Unmapped group"],
    ...options.claims,
  };
  const fetch = async (input: RequestInfo | URL, init?: RequestInit) => {
    const url = new URL(input instanceof Request ? input.url : typeof input === "string" ? input : input.toString());
    options.seen?.push(url);
    if (url.pathname.includes(".well-known/")) {
      if (options.discoveryResponse) return await options.discoveryResponse(init);
      return Response.json({
        issuer: options.discoveryIssuer ?? issuer,
        authorization_endpoint: `${issuer}/authorize`,
        token_endpoint: `${issuer}/token`,
        jwks_uri: `${issuer}/jwks`,
        response_types_supported: ["code"],
        grant_types_supported: ["authorization_code"],
        subject_types_supported: ["public"],
        id_token_signing_alg_values_supported: ["RS256"],
        ...options.discoveryMetadata,
      });
    }
    if (url.pathname === "/jwks") return options.jwksResponse ? await options.jwksResponse(init) : Response.json({ keys: [jwk] });
    if (url.pathname === "/token") {
      if (options.tokenResponse) return await options.tokenResponse(init);
      return Response.json({
        token_type: "Bearer",
        access_token: "access-token-must-not-be-persisted",
        refresh_token: "refresh-token-must-not-be-persisted",
        id_token: token(claims, options.invalidSignature),
      });
    }
    return new Response(null, { status: 404 });
  };
  const protocolOptions = {
    issuer,
    clientId,
    clientSecret: "client-secret-must-not-be-persisted",
    callbackUrl,
    scopes: ["openid", "profile"],
    groupsClaim: "groups",
    fetch,
    ...(options.httpTimeoutMs === undefined ? {} : { httpTimeoutMs: options.httpTimeoutMs }),
    ...(options.jwksTimeoutMs === undefined ? {} : { jwksTimeoutMs: options.jwksTimeoutMs }),
  } as Parameters<typeof createOidcProtocol>[0];
  return createOidcProtocol(protocolOptions);
}

async function callback(subject = protocol()) {
  return subject.callback({
    currentUrl: new URL(`${callbackUrl}?code=good&state=${state}`), state, nonce, codeVerifier: verifier,
  });
}

async function settlesWithin(operation: Promise<unknown>, timeoutMs = 150): Promise<"resolved" | "rejected" | "timed-out"> {
  return await new Promise((resolve) => {
    const timeout = setTimeout(() => resolve("timed-out"), timeoutMs);
    operation.then(
      () => { clearTimeout(timeout); resolve("resolved"); },
      () => { clearTimeout(timeout); resolve("rejected"); },
    );
  });
}

test("uses HTTPS discovery, Authorization Code, and PKCE S256 without external network", async () => {
  const seen: URL[] = [];
  const subject = protocol({ seen });
  const authorization = await subject.authorizationUrl({ state, nonce, codeVerifier: verifier });

  expect(authorization.origin).toBe(issuer);
  expect(authorization.pathname).toBe("/authorize");
  expect(Object.fromEntries(authorization.searchParams)).toMatchObject({
    response_type: "code", client_id: clientId, redirect_uri: callbackUrl, state, nonce,
    code_challenge_method: "S256", scope: "openid profile",
  });
  expect(authorization.searchParams.get("code_challenge")).not.toBe(verifier);
  await expect(callback(subject)).resolves.toEqual({
    issuer, subject: "user-123", displayName: "Ada Lovelace",
    groups: ["TOT Users", "Unmapped group"], tokenExpiresAt: expect.any(Date),
  });
  expect(seen.map((url) => url.origin)).toEqual([issuer, issuer, issuer]);
});

test("rejects a hanging discovery request at the provider transport deadline", async () => {
  let aborted = false;
  const subject = protocol({
    httpTimeoutMs: 20,
    discoveryResponse: (init) => new Promise<Response>((_resolve, reject) => {
      init?.signal?.addEventListener("abort", () => {
        aborted = true;
        reject(new DOMException("aborted", "AbortError"));
      }, { once: true });
    }),
  });

  const completion = subject.authorizationUrl({ state, nonce, codeVerifier: verifier });
  expect(await settlesWithin(completion)).toBe("rejected");
  const error = await completion.catch((reason: unknown) => reason);
  expect(error).toBeInstanceOf(OidcProviderUnavailableError);
  expect((error as Error).message).toBe("oidc_provider_unavailable");
  expect(aborted).toBe(true);
});

test("rejects oversized discovery Content-Length before reading or buffering its body", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      controller.enqueue(new TextEncoder().encode("{}"));
      controller.close();
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({
    discoveryResponse: () => new Response(body, { headers: { "content-length": String(1024 * 1024 + 1) } }),
  });

  await expect(subject.authorizationUrl({ state, nonce, codeVerifier: verifier })).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(0);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("stops chunked discovery streaming at the provider response limit", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      if (pulls === 1) controller.enqueue(new Uint8Array(700_000));
      else if (pulls === 2) controller.enqueue(new Uint8Array(400_000));
      else {
        controller.enqueue(new Uint8Array([1]));
        controller.close();
      }
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({ discoveryResponse: () => new Response(body) });

  await expect(subject.authorizationUrl({ state, nonce, codeVerifier: verifier })).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(2);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("rejects a hanging token exchange at the provider transport deadline", async () => {
  let aborted = false;
  const subject = protocol({
    httpTimeoutMs: 20,
    tokenResponse: (init) => new Promise<Response>((_resolve, reject) => {
      init?.signal?.addEventListener("abort", () => {
        aborted = true;
        reject(new DOMException("aborted", "AbortError"));
      }, { once: true });
    }),
  });
  await subject.authorizationUrl({ state, nonce, codeVerifier: verifier });

  const completion = callback(subject);
  expect(await settlesWithin(completion)).toBe("rejected");
  const error = await completion.catch((reason: unknown) => reason);
  expect(error).toBeInstanceOf(OidcProviderUnavailableError);
  expect((error as Error).message).toBe("oidc_provider_unavailable");
  expect(aborted).toBe(true);
});

test("rejects oversized token Content-Length before reading or buffering its body", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      controller.enqueue(new TextEncoder().encode("{}"));
      controller.close();
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({
    tokenResponse: () => new Response(body, { headers: { "content-length": String(1024 * 1024 + 1) } }),
  });
  await subject.authorizationUrl({ state, nonce, codeVerifier: verifier });

  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(0);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("stops chunked token streaming at the provider response limit", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      if (pulls === 1) controller.enqueue(new Uint8Array(700_000));
      else if (pulls === 2) controller.enqueue(new Uint8Array(400_000));
      else {
        controller.enqueue(new Uint8Array([1]));
        controller.close();
      }
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({ tokenResponse: () => new Response(body) });
  await subject.authorizationUrl({ state, nonce, codeVerifier: verifier });

  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(2);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("fails promptly and releases a provider response whose cancellation never settles", async () => {
  let cancelled = false;
  const body = new ReadableStream({
    pull() { return new Promise<void>(() => { /* no body bytes are ever delivered */ }); },
    cancel() {
      cancelled = true;
      return new Promise<void>(() => { /* cancellation remains advisory */ });
    },
  });
  const subject = protocol({
    discoveryResponse: () => new Response(body, { headers: { "content-length": String(1024 * 1024 + 1) } }),
  });

  const completion = subject.authorizationUrl({ state, nonce, codeVerifier: verifier });
  expect(await settlesWithin(completion)).toBe("rejected");
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("rejects non-HTTPS issuer configuration and a discovery issuer mismatch", async () => {
  expect(() => createOidcProtocol({
    issuer: "http://issuer.example.test", clientId, clientSecret: "secret", callbackUrl,
    scopes: ["openid"], groupsClaim: "groups",
  })).toThrow(OidcProtocolError);
  try {
    await protocol({ discoveryIssuer: "https://other.example.test" })
      .authorizationUrl({ state, nonce, codeVerifier: verifier });
    throw new Error("issuer mismatch unexpectedly accepted");
  } catch (error) {
    expect(error).toBeInstanceOf(OidcIssuerMismatchError);
    expect((error as Error).message).toBe("oidc_issuer_mismatch");
  }
});

test.each([
  ["authorization", { authorization_endpoint: "http://127.0.0.1/authorize" }],
  ["token", { token_endpoint: "http://127.0.0.1/token" }],
  ["JWKS", { jwks_uri: "http://127.0.0.1/jwks" }],
])("keeps the discovered %s endpoint HTTPS-only", async (_label, discoveryMetadata) => {
  const subject = protocol({ discoveryMetadata });
  await expect(subject.authorizationUrl({ state, nonce, codeVerifier: verifier }))
    .rejects.toThrow(OidcProtocolError);
});

test.each([
  "http://127.0.0.1:3000/api/auth/oidc/callback",
  "http://127.255.255.254/api/auth/oidc/callback",
  "http://[::1]:3000/api/auth/oidc/callback",
  "https://thothii.example.test/api/auth/oidc/callback",
])("accepts the configured callback URL %s", (configuredCallbackUrl) => {
  expect(() => createOidcProtocol({
    issuer, clientId, clientSecret: "secret", callbackUrl: configuredCallbackUrl,
    scopes: ["openid"], groupsClaim: "groups",
  })).not.toThrow();
});

test.each([
  "http://localhost/api/auth/oidc/callback",
  "http://loopback.example.test/api/auth/oidc/callback",
  "http://user@127.0.0.1/api/auth/oidc/callback",
  "http://127.1/api/auth/oidc/callback",
  "http://127.0.0.01/api/auth/oidc/callback",
  "http://0177.0.0.1/api/auth/oidc/callback",
  "http://0x7f000001/api/auth/oidc/callback",
  "http://2130706433/api/auth/oidc/callback",
  "http://[::ffff:127.0.0.1]/api/auth/oidc/callback",
  "http://128.0.0.1/api/auth/oidc/callback",
  "http://192.168.1.1/api/auth/oidc/callback",
])("rejects the non-canonical or non-loopback HTTP callback URL %s", (configuredCallbackUrl) => {
  expect(() => createOidcProtocol({
    issuer, clientId, clientSecret: "secret", callbackUrl: configuredCallbackUrl,
    scopes: ["openid"], groupsClaim: "groups",
  })).toThrow(OidcProtocolError);
});

test.each([
  ["state", new URL(`${callbackUrl}?code=good&state=wrong`), {}],
  ["nonce", new URL(`${callbackUrl}?code=good&state=${state}`), { nonce: "wrong" }],
  ["audience", new URL(`${callbackUrl}?code=good&state=${state}`), { aud: "someone-else" }],
  ["issuer", new URL(`${callbackUrl}?code=good&state=${state}`), { iss: "https://other.example.test" }],
  ["expiry", new URL(`${callbackUrl}?code=good&state=${state}`), { exp: Math.floor(Date.now() / 1000) - 1 }],
  ["subject", new URL(`${callbackUrl}?code=good&state=${state}`), { sub: undefined }],
])("rejects invalid %s claims or callback bindings", async (_label, currentUrl, claims) => {
  const subject = protocol({ claims });
  await expect(subject.callback({ currentUrl, state, nonce, codeVerifier: verifier })).rejects.toThrow(OidcProtocolError);
});

test("rejects invalid ID-token signatures", async () => {
  await expect(callback(protocol({ invalidSignature: true }))).rejects.toThrow(OidcProtocolError);
});

test("aborts a hanging JWKS request at the configured timeout", async () => {
  let aborted = false;
  const subject = protocol({
    jwksTimeoutMs: 20,
    jwksResponse: (init) => new Promise<Response>((_resolve, reject) => {
      const fallback = setTimeout(() => reject(new Error("JWKS fixture was not aborted")), 200);
      init?.signal?.addEventListener("abort", () => {
        aborted = true;
        clearTimeout(fallback);
        reject(new DOMException("aborted", "AbortError"));
      }, { once: true });
    }),
  });
  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(aborted).toBe(true);
});

test("diagnose validates the bounded JWKS endpoint after discovery", async () => {
  const subject = protocol({ jwksResponse: () => new Response("upstream JWKS body", { status: 503 }) });

  await expect(subject.diagnose(new AbortController().signal)).rejects.toBeInstanceOf(OidcJwksUnavailableError);
});

test("rejects an oversized JWKS Content-Length before reading the body", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      controller.enqueue(new TextEncoder().encode("{}"));
      controller.close();
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({
    jwksResponse: () => new Response(body, { headers: { "content-length": String(1024 * 1024 + 1) } }),
  });
  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(0);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("cancels and releases a JWKS stream with an invalid Content-Length", async () => {
  let cancelled = false;
  const body = new ReadableStream({
    pull() { /* remains pending until the response is rejected and cancelled */ },
    cancel() { cancelled = true; },
  });
  const subject = protocol({
    jwksResponse: () => new Response(body, { headers: { "content-length": "not-a-number" } }),
  });

  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("cancels and releases a non-success JWKS response body", async () => {
  let cancelled = false;
  const body = new ReadableStream({
    pull() { /* remains pending until the response is rejected and cancelled */ },
    cancel() { cancelled = true; },
  });
  const subject = protocol({ jwksResponse: () => new Response(body, { status: 503 }) });

  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("rejects promptly and releases the JWKS reader when stream cancellation never settles", async () => {
  let cancelled = false;
  const body = new ReadableStream({
    pull() { /* a non-success response is rejected before any body read */ },
    cancel() {
      cancelled = true;
      return new Promise<void>(() => { /* deliberately never settles */ });
    },
  });
  const subject = protocol({ jwksResponse: () => new Response(body, { status: 503 }) });
  const completion = callback(subject).then(() => "resolved" as const, () => "rejected" as const);
  const outcome = await Promise.race([
    completion,
    new Promise<"timed-out">((resolve) => setTimeout(() => resolve("timed-out"), 100)),
  ]);

  expect(outcome).toBe("rejected");
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("preserves the JWKS body timeout when cancellation never settles", async () => {
  let cancelled = false;
  const body = new ReadableStream({
    pull() { return new Promise<void>(() => { /* body read deliberately hangs */ }); },
    cancel() {
      cancelled = true;
      return new Promise<void>(() => { /* deliberately never settles */ });
    },
  });
  const subject = protocol({
    jwksTimeoutMs: 20,
    jwksResponse: () => new Response(body),
  });
  const completion = callback(subject).then(() => "resolved" as const, () => "rejected" as const);
  const outcome = await Promise.race([
    completion,
    new Promise<"timed-out">((resolve) => setTimeout(() => resolve("timed-out"), 100)),
  ]);

  expect(outcome).toBe("rejected");
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test("stops streaming a JWKS response as soon as the byte limit is exceeded", async () => {
  let pulls = 0;
  let cancelled = false;
  const body = new ReadableStream({
    type: "bytes",
    pull(controller) {
      pulls += 1;
      if (pulls === 1) controller.enqueue(new Uint8Array(700_000));
      else if (pulls === 2) controller.enqueue(new Uint8Array(400_000));
      else {
        controller.enqueue(new Uint8Array([1]));
        controller.close();
      }
    },
    cancel() { cancelled = true; },
  });
  const subject = protocol({ jwksResponse: () => new Response(body) });
  await expect(callback(subject)).rejects.toThrow(OidcProtocolError);
  expect(pulls).toBe(2);
  expect(cancelled).toBe(true);
  expect(body.locked).toBe(false);
});

test.each([
  ["absent", { groups: undefined }],
  ["non-array", { groups: "TOT Users" }],
  ["empty array", { groups: [] }],
  ["empty", { groups: [""] }],
  ["duplicate", { groups: ["TOT Users", "TOT Users"] }],
  ["control", { groups: ["TOT\u0000Users"] }],
  ["oversized", { groups: ["x".repeat(257)] }],
  ["distributed", { _claim_names: { groups: "source" }, _claim_sources: { source: { endpoint: "https://issuer.example.test/claims" } } }],
  ["overage", { hasgroups: true }],
])("rejects %s mandatory groups claims", async (_label, claims) => {
  await expect(callback(protocol({ claims }))).rejects.toThrow(OidcProtocolError);
});