import { afterEach, describe, expect, it, vi } from "vitest";
import { createServer, type Server } from "node:http";
import type { AddressInfo } from "node:net";
import { rmSync } from "node:fs";
import { Agent, interceptors } from "undici";
import {
    UrlNotAllowedError,
    assertDownloadableUrl,
    createGuardedConnector,
    isBlockedAddress,
} from "../src/lib/netGuard.js";
import { loadModules } from "./helpers.js";

// Resolve "internal.test" para um IP privado e o resto para um público,
// sem depender de DNS real.
vi.mock("node:dns", () => ({
    lookup: (
        host: string,
        opts: { all?: boolean },
        cb: (err: Error | null, address: unknown, family?: number) => void,
    ) => {
        const address = host === "internal.test" ? "10.0.0.5" : "93.184.216.34";
        if (opts?.all) cb(null, [{ address, family: 4 }]);
        else cb(null, address, 4);
    },
}));

afterEach(() => {
    delete process.env.ALLOW_PRIVATE_NETWORK;
});

describe("isBlockedAddress", () => {
    it.each([
        "0.0.0.0", "10.1.2.3", "100.64.0.1", "127.0.0.1", "169.254.169.254",
        "172.16.0.1", "172.31.255.255", "192.168.1.1", "198.18.0.1", "224.0.0.1",
        "255.255.255.255", "::", "::1", "fc00::1", "fd12:3456::1", "fe80::1",
        "ff02::1", "::ffff:127.0.0.1", "::ffff:7f00:1", "::ffff:10.0.0.1",
        "64:ff9b::7f00:1",
    ])("bloqueia %s", (ip) => {
        expect(isBlockedAddress(ip)).toBe(true);
    });

    it.each([
        "8.8.8.8", "1.1.1.1", "93.184.216.34", "172.15.0.1", "172.32.0.1",
        "100.63.0.1", "198.20.0.1", "2606:4700:4700::1111", "::ffff:8.8.8.8",
    ])("permite %s", (ip) => {
        expect(isBlockedAddress(ip)).toBe(false);
    });

    it("bloqueia o que não é IP", () => {
        expect(isBlockedAddress("example.com")).toBe(true);
    });
});

describe("assertDownloadableUrl", () => {
    it("aceita http e https públicos", () => {
        expect(assertDownloadableUrl("https://example.com/a.zip").hostname).toBe("example.com");
        expect(assertDownloadableUrl("http://8.8.8.8/a.zip").hostname).toBe("8.8.8.8");
    });

    it.each(["ftp://example.com/a", "file:///etc/passwd", "javascript:alert(1)"])(
        "recusa o protocolo de %s",
        (url) => {
            expect(() => assertDownloadableUrl(url)).toThrow(/http and https/);
        },
    );

    it("recusa URL inválida", () => {
        expect(() => assertDownloadableUrl("not a url")).toThrow(UrlNotAllowedError);
    });

    it.each([
        "http://localhost:3000/", "http://app.localhost/", "http://127.0.0.1/",
        "http://[::1]/", "http://169.254.169.254/latest/meta-data/",
        "http://10.0.0.1/", "http://192.168.0.10:8080/", "http://[::ffff:127.0.0.1]/",
        "http://2130706433/", // 127.0.0.1 em decimal: o parser do WHATWG normaliza
    ])("recusa %s", (url) => {
        expect(() => assertDownloadableUrl(url)).toThrow(/local or private/);
    });

    it("libera endereços privados com ALLOW_PRIVATE_NETWORK=true", () => {
        process.env.ALLOW_PRIVATE_NETWORK = "true";
        expect(assertDownloadableUrl("http://127.0.0.1/").hostname).toBe("127.0.0.1");
    });
});

describe("createGuardedConnector", () => {
    const connect = (hostname: string) =>
        new Promise<Error | null>((done) => {
            const connector = createGuardedConnector({ timeout: 2000 });
            connector({ hostname, host: hostname, protocol: "http:", port: "9" }, (err, socket) => {
                socket?.destroy();
                done(err);
            });
        });

    it("recusa IP literal privado antes de conectar", async () => {
        expect(await connect("127.0.0.1")).toBeInstanceOf(UrlNotAllowedError);
    });

    it("recusa nome que resolve para IP privado", async () => {
        const err = await connect("internal.test");
        expect(err).toBeInstanceOf(UrlNotAllowedError);
        expect(err?.message).toMatch(/internal\.test resolves/);
    });

    it("deixa passar nome que resolve para IP público (falha só ao conectar)", async () => {
        const err = await connect("public.test");
        expect(err).not.toBeInstanceOf(UrlNotAllowedError);
    });
});

describe("DownloadManager com a proteção", () => {
    let origin: Server | undefined;

    afterEach(async () => {
        if (origin) await new Promise((done) => origin!.close(done));
        origin = undefined;
    });

    async function startOrigin(handler: Parameters<typeof createServer>[1]) {
        origin = createServer(handler);
        await new Promise<void>((done) => origin!.listen(0, "127.0.0.1", done));
        return (origin.address() as AddressInfo).port;
    }

    async function waitWhileDownloading(read: () => string | undefined) {
        for (let i = 0; i < 500 && read() === "downloading"; i++) {
            await new Promise((done) => setTimeout(done, 5));
        }
    }

    it("recusa enfileirar URL privada", async () => {
        const { sessionManager, DownloadManager, storageRoot } = await loadModules();
        const manager = new DownloadManager(new Agent());
        const session = sessionManager.getSession();
        // loadModules() reimporta os módulos, então a classe não é a mesma: compara pelo nome.
        await expect(manager.queueDownload(session.id, "http://127.0.0.1:1/x")).rejects.toMatchObject({
            name: "UrlNotAllowedError",
        });
        expect(manager.getTasks(session.id)).toEqual([]);
        rmSync(storageRoot, { recursive: true, force: true });
    });

    it("segue redirect e salva o arquivo final, não o corpo do 302", async () => {
        process.env.ALLOW_PRIVATE_NETWORK = "true";
        const port = await startOrigin((req, res) => {
            if (req.url === "/start") {
                res.writeHead(302, { location: "/final.bin" });
                res.end("redirecting");
                return;
            }
            res.setHeader("content-length", "5");
            res.end("hello");
        });

        const { sessionManager, DownloadManager, storageRoot } = await loadModules();
        const agent = new Agent({ connect: createGuardedConnector({ timeout: 2000 }) }).compose(
            interceptors.redirect({ maxRedirections: 5 }),
        );
        const manager = new DownloadManager(agent);
        const session = sessionManager.getSession();
        const task = await manager.queueDownload(session.id, `http://127.0.0.1:${port}/start`);
        await waitWhileDownloading(() => manager.getTask(task.id)?.status);

        const finished = manager.getTask(task.id)!;
        expect(finished.status).toBe("completed");
        expect(finished.totalBytes).toBe(5);
        rmSync(storageRoot, { recursive: true, force: true });
    });

    it("marca erro quando a resposta 3xx não é seguida", async () => {
        process.env.ALLOW_PRIVATE_NETWORK = "true";
        const port = await startOrigin((_req, res) => {
            res.writeHead(302);
            res.end("nope");
        });

        const { sessionManager, DownloadManager, storageRoot } = await loadModules();
        const manager = new DownloadManager(new Agent());
        const session = sessionManager.getSession();
        const task = await manager.queueDownload(session.id, `http://127.0.0.1:${port}/`);
        await waitWhileDownloading(() => manager.getTask(task.id)?.status);

        expect(manager.getTask(task.id)).toMatchObject({ status: "error", error: "HTTP Error 302" });
        rmSync(storageRoot, { recursive: true, force: true });
    });
});