import { describe, expect, it } from 'vitest'
import { AUTH_HEADERS, Ed25519Signer, Ed25519Verifier, RequestAuth, type RequestSigner, type SignatureVerifier } from '../../src/utils/request-auth.js'
import { AuthError } from '../../src/utils/errors.js'

const NOW = 1_700_000_000_000

async function signed(signer: RequestSigner, path = '/kv/readMany', body = '{"keys":["a"]}', at = NOW) {
  return new Headers(await RequestAuth.headers(signer, path, body, at))
}

describe('RequestAuth', () => {
  it('accepts a correctly signed request and returns the public key', async () => {
    const signer = await Ed25519Signer.generate()
    const auth = new RequestAuth([new Ed25519Verifier()], { now: () => NOW })
    const headers = await signed(signer)
    expect(headers.get(AUTH_HEADERS.algorithm)).toBe('ed25519')
    expect(signer.publicKey).toMatch(/^[0-9a-f]{64}$/)
    expect(await auth.verify(headers, '/kv/readMany', '{"keys":["a"]}')).toBe(signer.publicKey)
  })

  it('rejects tampered bodies, paths and timestamps', async () => {
    const signer = await Ed25519Signer.generate()
    const auth = new RequestAuth([new Ed25519Verifier()], { now: () => NOW })
    await expect(auth.verify(await signed(signer), '/kv/readMany', '{"keys":["b"]}')).rejects.toThrow(/Invalid signature/)
    await expect(auth.verify(await signed(signer), '/kv/writeMany', '{"keys":["a"]}')).rejects.toThrow(/Invalid signature/)
    const headers = await signed(signer)
    headers.set(AUTH_HEADERS.timestamp, String(NOW + 1))
    await expect(auth.verify(headers, '/kv/readMany', '{"keys":["a"]}')).rejects.toThrow(/Invalid signature/)
    const other = await Ed25519Signer.generate()
    const swapped = await signed(signer)
    swapped.set(AUTH_HEADERS.publicKey, other.publicKey)
    await expect(auth.verify(swapped, '/kv/readMany', '{"keys":["a"]}')).rejects.toThrow(/Invalid signature/)
  })

  it('rejects old or future timestamps, replays, missing headers and unknown algorithms', async () => {
    const signer = await Ed25519Signer.generate()
    const auth = new RequestAuth([new Ed25519Verifier()], { now: () => NOW, maxSkewMs: 1000 })
    await expect(auth.verify(await signed(signer, '/p', 'b', NOW - 5000), '/p', 'b')).rejects.toThrow(/window/)
    await expect(auth.verify(await signed(signer, '/p', 'b', NOW + 5000), '/p', 'b')).rejects.toThrow(/window/)
    const once = await signed(signer, '/p', 'b')
    await auth.verify(once, '/p', 'b')
    await expect(auth.verify(once, '/p', 'b')).rejects.toThrow(/Replayed/)
    await expect(auth.verify(new Headers(), '/p', 'b')).rejects.toBeInstanceOf(AuthError)
    const unknown = await signed(signer, '/p', 'c')
    unknown.set(AUTH_HEADERS.algorithm, 'rot13')
    await expect(auth.verify(unknown, '/p', 'c')).rejects.toThrow(/Unsupported signature algorithm "rot13"/)
  })

  it('restores an Ed25519 key from its exported private key', async () => {
    const signer = await Ed25519Signer.generate()
    const restored = await Ed25519Signer.fromPrivateKey(await signer.exportPrivateKey())
    expect(restored.publicKey).toBe(signer.publicKey)
    const auth = new RequestAuth([new Ed25519Verifier()], { now: () => NOW })
    expect(await auth.verify(await signed(restored), '/kv/readMany', '{"keys":["a"]}')).toBe(signer.publicKey)
  })

  it('supports other algorithms through the verifier registry', async () => {
    // A toy algorithm (signature = sha256(publicKey + payload)) standing in for e.g. secp256k1 via libauth.
    const digest = async (publicKey: string, payload: Uint8Array) =>
      new Uint8Array(await crypto.subtle.digest('SHA-256', new Uint8Array([...new TextEncoder().encode(publicKey), ...payload])))
    const toySigner: RequestSigner = { algorithm: 'toy', publicKey: 'abcd', sign: (payload) => digest('abcd', payload) }
    const toyVerifier: SignatureVerifier = {
      algorithm: 'toy',
      verify: async (publicKey, payload, signature) => (await digest(publicKey, payload)).every((byte, i) => byte === signature[i]),
    }
    const auth = new RequestAuth([new Ed25519Verifier(), toyVerifier], { now: () => NOW })
    expect(await auth.verify(await signed(toySigner), '/kv/readMany', '{"keys":["a"]}')).toBe('abcd')
  })
})