import type { Did } from "@atcute/lexicons/syntax";
import {
	OAuthResponseError,
	OAuthUserAgent,
	TokenRefreshError,
	createAuthorizationUrl,
	deleteStoredSession,
	finalizeAuthorization,
	getSession,
	type Session
} from "@atcute/oauth-browser-client";
import { beforeEach, describe, expect, it, vi } from "vitest";
import {
	createDelegatedSession,
	delegatedSessionController,
	getOrCreateDelegatedSession
} from "$lib/api/actAs";

vi.mock("@atcute/oauth-browser-client", async (importOriginal) => {
	const mod = await importOriginal<Record<string, unknown>>();
	class MockOAuthUserAgent {
		readonly sub: string;
		constructor(readonly session: Session) {
			this.sub = session.info.sub;
		}
	}
	return {
		...mod,
		OAuthUserAgent: MockOAuthUserAgent,
		createAuthorizationUrl: vi.fn(),
		finalizeAuthorization: vi.fn(),
		getSession: vi.fn(),
		deleteStoredSession: vi.fn()
	};
});

const fetchMock = vi.fn<typeof globalThis.fetch>();
vi.stubGlobal("fetch", fetchMock);

const controllerDid = "did:plc:controller" as Did;
const delegatedDid = "did:plc:org" as Did;
const requestUri = "urn:ietf:params:oauth:request_uri:request-1";

const sessionWithClaims = (claims: unknown): Session => {
	const payload = btoa(JSON.stringify(claims))
		.replace(/=/g, "")
		.replace(/\+/g, "-")
		.replace(/\//g, "_");
	return { token: { access: `header.${payload}.signature` } } as Session;
};

// a session on pds.example for the org, minted by `controller`
const orgSession = (controller: string): Session =>
	({
		info: { sub: delegatedDid, aud: "https://pds.example" },
		token: {
			access: sessionWithClaims({ act: { sub: controller } }).token.access,
			scope: "atproto"
		},
		dpopKey: {}
	}) as Session;

const controllerAgentOn = (pds: string): OAuthUserAgent =>
	({
		sub: controllerDid,
		session: { info: { aud: pds }, token: { scope: "atproto repo:sh.tangled.repo" } },
		handle: vi.fn(async (_path: string, _init: RequestInit) =>
			Response.json({ token: "service-token" }, { status: 200 })
		)
	}) as unknown as OAuthUserAgent;

// the headless flow on pds.example, answered the way tranquil would
const answerHeadlessFlow = (
	minted: Session,
	consent: unknown = { scopes: [{ scope: "atproto" }] }
) => {
	vi.mocked(createAuthorizationUrl).mockImplementation(async () => {
		const url = new URL("https://pds.example/oauth/authorize");
		url.searchParams.set("request_uri", requestUri);
		return url;
	});
	fetchMock
		.mockResolvedValueOnce(Response.json({ success: true }))
		.mockResolvedValueOnce(Response.json(consent))
		.mockResolvedValueOnce(
			Response.json({
				redirect_uri:
					"https://pds.example/oauth/authorize/redirect?code=code-1&state=state-1"
			})
		);
	vi.mocked(finalizeAuthorization).mockResolvedValue({ session: minted, state: null });
};

beforeEach(() => {
	vi.clearAllMocks();
	fetchMock.mockReset();
});

describe("delegatedSessionController", () => {
	it("returns the controller DID from the access token act claim", () => {
		expect(delegatedSessionController(sessionWithClaims({ act: { sub: controllerDid } }))).toBe(
			controllerDid
		);
	});

	it("rejects sessions without a valid controller claim", () => {
		expect(delegatedSessionController(sessionWithClaims({ sub: "did:plc:org" }))).toBeNull();
		expect(delegatedSessionController({ token: { access: "opaque" } } as Session)).toBeNull();
	});
});

describe("createDelegatedSession", () => {
	it.each(["https://pds.example", "https://remote.example"])(
		"authorizes headlessly for a controller on %s",
		async (controllerPds) => {
			const controllerAgent = controllerAgentOn(controllerPds);
			const session = orgSession(controllerDid);
			answerHeadlessFlow(session, {
				scopes: [
					{ scope: "atproto" },
					{ scope: "repo:allowed" },
					{ scope: "repo:restricted", restricted: true }
				],
				permission_sets: [{ include_scope: "include:example.permissions" }]
			});

			const agent = await createDelegatedSession(controllerAgent, delegatedDid);

			expect(agent).toBeInstanceOf(OAuthUserAgent);
			expect(agent.session).toBe(session);
			const handle = vi.mocked(controllerAgent.handle);
			expect(handle).toHaveBeenCalledTimes(1);
			const authParams = new URL(String(handle.mock.calls[0][0]), controllerPds).searchParams;
			expect(authParams.get("aud")).toBe("did:web:pds.example");
			expect(authParams.get("lxm")).toBe("farm.tranquil.delegation.authorize");
			expect(String(fetchMock.mock.calls[0][0])).toBe(
				"https://pds.example/oauth/delegation/auth-token"
			);
			expect(fetchMock.mock.calls[0][1]).toMatchObject({
				headers: { authorization: "Bearer service-token" },
				body: JSON.stringify({ request_uri: requestUri, delegated_did: delegatedDid })
			});
			expect(String(fetchMock.mock.calls[1][0])).toContain(
				"https://pds.example/oauth/authorize/consent?"
			);
			expect(fetchMock).toHaveBeenCalledTimes(3);
			const approval = fetchMock.mock.calls[2][1] as RequestInit;
			expect(JSON.parse(String(approval.body))).toEqual({
				request_uri: requestUri,
				approved_scopes: ["atproto", "repo:allowed", "include:example.permissions"],
				remember: false
			});
			expect(finalizeAuthorization).toHaveBeenCalledTimes(1);
			const params = vi.mocked(finalizeAuthorization).mock.calls[0][0];
			expect(Object.fromEntries(params)).toEqual({
				iss: "https://pds.example",
				code: "code-1",
				state: "state-1"
			});
		}
	);
});

describe("getOrCreateDelegatedSession", () => {
	const controllerAgent = controllerAgentOn("https://pds.example");

	it("keeps the personal session when the owner is the controller", async () => {
		const agent = await getOrCreateDelegatedSession(controllerAgent, controllerDid);

		expect(agent).toBe(controllerAgent);
		expect(getSession).not.toHaveBeenCalled();
		expect(deleteStoredSession).not.toHaveBeenCalled();
		expect(createAuthorizationUrl).not.toHaveBeenCalled();
	});

	it("reuses a stored session minted by this controller", async () => {
		const stored = orgSession(controllerDid);
		vi.mocked(getSession).mockResolvedValue(stored);

		const agent = await getOrCreateDelegatedSession(controllerAgent, delegatedDid);

		expect(agent.session).toBe(stored);
		expect(createAuthorizationUrl).not.toHaveBeenCalled();
		expect(deleteStoredSession).not.toHaveBeenCalled();
	});

	it.each([
		["a revoked refresh token", new TokenRefreshError(delegatedDid, "session was revoked")],
		[
			"an invalid_token answer from the token endpoint",
			new OAuthResponseError(new Response(null, { status: 400 }), {
				error: "invalid_token",
				error_description: '"exp" claim timestamp check failed'
			})
		]
	])("remints after %s", async (_label, cause) => {
		const minted = orgSession(controllerDid);
		vi.mocked(getSession).mockRejectedValue(cause);
		answerHeadlessFlow(minted);

		const agent = await getOrCreateDelegatedSession(controllerAgent, delegatedDid);

		expect(finalizeAuthorization).toHaveBeenCalledTimes(1);
		expect(agent.session).toBe(minted);
	});

	it("remints when the stored session was minted by another controller", async () => {
		vi.mocked(getSession).mockResolvedValue(orgSession("did:plc:other"));
		answerHeadlessFlow(orgSession(controllerDid));

		await getOrCreateDelegatedSession(controllerAgent, delegatedDid);

		expect(deleteStoredSession).toHaveBeenCalledWith(delegatedDid);
		expect(finalizeAuthorization).toHaveBeenCalledTimes(1);
	});

	it("keeps a session that only failed transiently", async () => {
		const cause = new TypeError("fetch failed");
		vi.mocked(getSession).mockRejectedValue(cause);

		await expect(getOrCreateDelegatedSession(controllerAgent, delegatedDid)).rejects.toBe(
			cause
		);
		expect(finalizeAuthorization).not.toHaveBeenCalled();
	});
});