import { describe, expect, it } from "vitest";
import {
  Identity,
  NostrSecret,
  dnsTxtValue,
  newClaimPayload,
  signClaim,
  toCompact,
} from "@kez/core";
import { ChannelError } from "../src/index.js";
import { DnsChannel, looksLikeKezTxt, type TxtResolver } from "../src/dns.js";

class CapturingResolver implements TxtResolver {
  constructor(
    private readonly records: string[],
    private readonly expectedName: string,
  ) {}
  async lookupTxt(name: string): Promise<string[]> {
    expect(name).toBe(this.expectedName);
    return this.records;
  }
}

class FailingResolver implements TxtResolver {
  async lookupTxt(): Promise<string[]> {
    throw ChannelError.unreachable("simulated network failure");
  }
}

function signDns(subject: string) {
  const secret = NostrSecret.generate();
  return signClaim(
    newClaimPayload(Identity.parse(subject), secret.identity(), new Date()),
    secret,
  );
}

describe("DnsChannel", () => {
  it("queries _kez.<domain>", async () => {
    const signed = signDns("dns:jason.example.com");
    const channel = new DnsChannel(
      new CapturingResolver([toCompact(signed)], "_kez.jason.example.com"),
    );
    const hit = await channel.fetchAndVerify(Identity.parse("dns:jason.example.com"));
    expect(hit.proof).toEqual(signed);
  });

  it("supports legacy kez1: prefix", async () => {
    const signed = signDns("dns:jason.example.com");
    const legacy = dnsTxtValue(signed);
    expect(legacy.startsWith("kez1:")).toBe(true);
    const channel = new DnsChannel(
      new CapturingResolver([legacy], "_kez.jason.example.com"),
    );
    const hit = await channel.fetchAndVerify(Identity.parse("dns:jason.example.com"));
    expect(hit.proof).toEqual(signed);
  });

  it("returns NotFound when no records", async () => {
    const channel = new DnsChannel(new CapturingResolver([], "_kez.jason.example.com"));
    await expect(
      channel.fetchAndVerify(Identity.parse("dns:jason.example.com")),
    ).rejects.toMatchObject({ kind: "NotFound" });
  });

  it("skips non-KEZ TXT records", async () => {
    const channel = new DnsChannel(
      new CapturingResolver(
        ["v=spf1 -all", "google-site-verification=abc"],
        "_kez.jason.example.com",
      ),
    );
    await expect(
      channel.fetchAndVerify(Identity.parse("dns:jason.example.com")),
    ).rejects.toMatchObject({ kind: "NotFound" });
  });

  it("surfaces resolver failure as Unreachable", async () => {
    const channel = new DnsChannel(new FailingResolver());
    await expect(
      channel.fetchAndVerify(Identity.parse("dns:jason.example.com")),
    ).rejects.toMatchObject({ kind: "Unreachable" });
  });
});

describe("looksLikeKezTxt", () => {
  it("accepts both prefixes", () => {
    expect(looksLikeKezTxt("kez:z1:foo")).toBe(true);
    expect(looksLikeKezTxt("kez1:{...}")).toBe(true);
    expect(looksLikeKezTxt("v=spf1")).toBe(false);
    expect(looksLikeKezTxt("")).toBe(false);
  });
});