package com.peachpasswords.sync

import org.junit.Assert.assertEquals
import org.junit.Assert.assertNull
import org.junit.Test

/**
 * The phone is the only side that generates pairing codes and the browser is
 * the only side that reads them, so a drift here is invisible until a real
 * pairing fails with nothing to look at. The golden vector below was produced
 * by running the browser's own `shared/pairing-code.ts` — not derived from this
 * implementation — so it fails if either side moves.
 */
class PairingCodeTest {

    // encodePairingCode("192.168.7.115", 49142, deadbeef01234567) in peach-browser.
    private val vectorCode = "R2M0-EWXZ-YVFA-VFQF-04HM-ASR"
    private val vectorToken = byteArrayOf(
        0xde.toByte(), 0xad.toByte(), 0xbe.toByte(), 0xef.toByte(), 0x01, 0x23, 0x45, 0x67,
    )

    @Test fun `encodes the browser's golden vector`() {
        assertEquals(vectorCode, PairingCode.encode("192.168.7.115", 49142, vectorToken))
    }

    @Test fun `parses the browser's golden vector`() {
        val parsed = PairingCode.parse(vectorCode)!!
        assertEquals("192.168.7.115", parsed.ip)
        assertEquals(49142, parsed.port)
        assertEquals("deadbeef01234567", parsed.tokenHex)
    }

    @Test fun `round-trips a freshly generated token`() {
        val token = PairingCode.newToken()
        val parsed = PairingCode.parse(PairingCode.encode("10.0.0.7", 8765, token))!!
        assertEquals("10.0.0.7", parsed.ip)
        assertEquals(8765, parsed.port)
        assertEquals(token.joinToString("") { "%02x".format(it) }, parsed.tokenHex)
    }

    @Test fun `folds the ambiguous glyphs a user might read off a screen`() {
        // I/L -> 1 and O -> 0, so the doc's own example resolves rather than
        // failing on characters Crockford's alphabet excludes.
        val typed = PairingCode.parse("r2mO-ewxz-yvfa-vfqf-O4hm-asr")
        assertEquals(PairingCode.parse(vectorCode), typed)
    }

    @Test fun `rejects input that is not a pairing code`() {
        assertNull(PairingCode.parse(""))
        assertNull(PairingCode.parse("418207"))          // the 6-digit SAS
        assertNull(PairingCode.parse("not-a-code!!"))    // U is not in the alphabet
    }

    @Test(expected = IllegalArgumentException::class)
    fun `refuses to encode a zero port`() {
        PairingCode.encode("10.0.0.1", 0, PairingCode.newToken())
    }

    @Test(expected = IllegalArgumentException::class)
    fun `refuses a token below the browser's four-byte floor`() {
        PairingCode.encode("10.0.0.1", 8765, byteArrayOf(1, 2, 3))
    }
}