package com.sptmobile.endpoint

import com.sptmobile.browse.WireEndpoint
import com.sptmobile.browse.WireSubnet
import org.junit.Assert.assertEquals
import org.junit.Assert.assertNull
import org.junit.Test

class DigestRouterTest {
    private fun listing(
        hostNode: String,
        localIds: Set<String>,
        subnets: List<WireSubnet> = emptyList(),
    ) = DigestRouter.HostListing(hostNode, localIds, subnets)

    // [unit->REQ-DIGEST-DIRECT-ROUTE]
    // Most-direct-route (ruling 4): the digest host is the FIRST host in
    // dial order whose `local` section carries the endpoint — a host that
    // merely SEES the endpoint in its subnet never serves its digest.
    @Test
    fun choose_picks_first_colocated_host_in_dial_order() {
        val listings = listOf(
            listing("host-a", localIds = setOf("other")),
            listing("host-b", localIds = setOf("flynn", "other")),
            listing("host-c", localIds = setOf("flynn")),
        )
        assertEquals("host-b", DigestRouter.choose("flynn", listings))
    }

    // [unit->REQ-DIGEST-DIRECT-ROUTE]
    @Test
    fun choose_is_null_when_no_host_is_colocated() {
        val seesButNotLocal = listing(
            "host-a",
            localIds = emptySet(),
            subnets = listOf(
                WireSubnet("SPT_DEV", listOf(WireEndpoint(id = "flynn", node = "n-remote")))
            ),
        )
        assertNull(DigestRouter.choose("flynn", listOf(seesButNotLocal)))
    }

    // [unit->REQ-ENDPOINT-INSTANCES]
    // The registry-card fallback carries the endpoint's Instance rows
    // (ruling 9: one row per node presence) unioned across hosts — same
    // (endpoint, node) reported by two hosts is ONE instance with both
    // hosts in `via`.
    @Test
    fun registry_card_unions_instances_across_hosts() {
        val subnetsA = listOf(
            WireSubnet(
                "SPT_DEV",
                listOf(
                    WireEndpoint(id = "flynn", node = "n-1", status = "Active"),
                    WireEndpoint(id = "other", node = "n-1", status = "Active"),
                ),
            )
        )
        val subnetsB = listOf(
            WireSubnet(
                "SPT_DEV",
                listOf(
                    WireEndpoint(id = "flynn", node = "n-1", status = "Active"),
                    WireEndpoint(id = "flynn", node = "n-2", status = "Suspended"),
                ),
            )
        )
        val card = DigestRouter.registryCard(
            "flynn",
            listOf(
                listing("host-a", emptySet(), subnetsA),
                listing("host-b", emptySet(), subnetsB),
            ),
        )
        assertEquals(listOf("n-1", "n-2"), card.map { it.node })
        assertEquals(listOf("host-a", "host-b"), card[0].via)
        assertEquals(listOf("host-b"), card[1].via)
    }
}