package io.flamenet.e2e

import kotlin.test.Test
import kotlin.test.assertEquals

/**
 * The salt for an account on a relay that keeps its own accounts.
 *
 * 🔴 **Pinned against the JavaScript engine, which is normative** — the value
 * below was produced by `engine/src/fnid.js`'s `localAccountSalt`, not by this
 * implementation. A Kotlin test that asserts what Kotlin computes proves only
 * that Kotlin is self-consistent; the failure this guards against is the three
 * engines disagreeing, which surfaces as one person having two addresses
 * depending on which phone they signed in from.
 *
 * ⚠️ Changing the expected value here is never the fix. It is a wire constant:
 * a different salt is a different account key, and a different account key is
 * a different person to everyone who pinned the old one.
 */
class LocalAccountSaltTest {

    @Test
    fun `matches the javascript engine`() {
        assertEquals(
            "331bfb32ce724a978dda86f671ac324a",
            AccountKdf.localAccountSalt("fnreviewalpha").toHex(),
        )
    }

    /** Normalisation is part of the contract, not a convenience. */
    @Test
    fun `case and surrounding space do not change the salt`() {
        val plain = AccountKdf.localAccountSalt("fnreviewalpha").toHex()
        assertEquals(plain, AccountKdf.localAccountSalt("FNReviewAlpha").toHex())
        assertEquals(plain, AccountKdf.localAccountSalt("  fnreviewalpha  ").toHex())
    }

    @Test
    fun `it is the length the KDF params ask for`() {
        assertEquals(
            AccountKdf.Params.PBKDF2_V1.saltBytes,
            AccountKdf.localAccountSalt("someone").size,
        )
    }

    private fun ByteArray.toHex() = joinToString("") { "%02x".format(it) }
}