fleetd/bridged/src/test/java/dev/ltms/bridged/mcp/PrimaryRegistryTest.java

package dev.ltms.bridged.mcp;

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.*;

/**
 * Unit tests for {@link PrimaryRegistry}: pin vs record, isKnown transitions,
 * null/blank guard.
 */
class PrimaryRegistryTest {

    @Test
    void unpinnedInitiallyUnknown() {
        var reg = new PrimaryRegistry(null);
        assertFalse(reg.isKnown());
        assertTrue(reg.primaryTerminal().isEmpty());
    }

    @Test
    void unpinnedAcceptsBlankAsAbsent() {
        var reg = new PrimaryRegistry("");
        assertFalse(reg.isKnown());
        assertTrue(reg.primaryTerminal().isEmpty());
    }

    @Test
    void pinnedFromConstruction() {
        var reg = new PrimaryRegistry("term_fixed");
        assertTrue(reg.isKnown());
        assertEquals("term_fixed", reg.primaryTerminal().orElseThrow());
    }

    @Test
    void recordWhenUnpinnedSetsTheTerminal() {
        var reg = new PrimaryRegistry(null);
        reg.record("term_abc");
        assertTrue(reg.isKnown());
        assertEquals("term_abc", reg.primaryTerminal().orElseThrow());
    }

    @Test
    void recordWithNullDoesNothingWhenUnpinned() {
        var reg = new PrimaryRegistry(null);
        reg.record(null);
        assertFalse(reg.isKnown());
    }

    @Test
    void recordWithBlankDoesNothingWhenUnpinned() {
        var reg = new PrimaryRegistry(null);
        reg.record("  ");
        assertFalse(reg.isKnown());
    }

    @Test
    void recordOverwritesWhenUnpinned() {
        var reg = new PrimaryRegistry(null);
        reg.record("term_first");
        assertEquals("term_first", reg.primaryTerminal().orElseThrow());
        reg.record("term_second");
        assertEquals("term_second", reg.primaryTerminal().orElseThrow());
    }

    @Test
    void recordIsIgnoredWhenPinned() {
        var reg = new PrimaryRegistry("term_pinned");
        reg.record("term_other");
        assertEquals("term_pinned", reg.primaryTerminal().orElseThrow(), "pinned value must survive record");
    }

    @Test
    void nullRecordIsIgnoredWhenPinned() {
        var reg = new PrimaryRegistry("term_pinned");
        reg.record(null);
        assertTrue(reg.isKnown());
        assertEquals("term_pinned", reg.primaryTerminal().orElseThrow());
    }

    @Test
    void blankRecordIsIgnoredWhenPinned() {
        var reg = new PrimaryRegistry("term_pinned");
        reg.record("  ");
        assertTrue(reg.isKnown());
        assertEquals("term_pinned", reg.primaryTerminal().orElseThrow());
    }

    @Test
    void isKnownFalseAfterConstructionWithNull() {
        var reg = new PrimaryRegistry(null);
        assertFalse(reg.isKnown());
    }

    @Test
    void isKnownAfterRecord() {
        var reg = new PrimaryRegistry(null);
        reg.record("term_x");
        assertTrue(reg.isKnown());
    }

    @Test
    void primaryTerminalRoundTrip() {
        var reg = new PrimaryRegistry(null);
        assertTrue(reg.primaryTerminal().isEmpty());
        reg.record("term_found");
        assertEquals("term_found", reg.primaryTerminal().get());
    }

    // ── CB-532: nudges follow the delegating lead, not "the primary" ────────────────────────────

    /**
     * The bug that made `primary.terminal` unretirable: with one slot, whichever lead called
     * bridge_send first captured every nudge — including nudges for the other lead's delegations.
     */
    @Test
    void aNudgeGoesToTheLeadThatDelegatedToThatWorker() {
        var reg = new PrimaryRegistry(null);
        reg.recordDelegation("term_worker_a", "term_lead_opus");
        reg.recordDelegation("term_worker_b", "term_lead_sol");

        assertEquals("term_lead_opus", reg.nudgeTargetFor("term_worker_a").orElseThrow());
        assertEquals("term_lead_sol", reg.nudgeTargetFor("term_worker_b").orElseThrow());
    }

    @Test
    void theMostRecentDelegatorWinsWhenAWorkerChangesHands() {
        var reg = new PrimaryRegistry(null);
        reg.recordDelegation("term_worker", "term_lead_opus");
        reg.recordDelegation("term_worker", "term_lead_sol");

        assertEquals("term_lead_sol", reg.nudgeTargetFor("term_worker").orElseThrow(),
                "the lead waiting on the reply is the one that sent the work most recently");
    }

    /** After a restart the map is empty while the durable inbox still holds the reply. */
    @Test
    void anUnknownDelegationFallsBackToThePinnedPrimary() {
        var reg = new PrimaryRegistry("term_pinned");

        assertEquals("term_pinned", reg.nudgeTargetFor("term_never_seen").orElseThrow());
    }

    @Test
    void withNoPinAndNoDelegationNobodyIsNudged() {
        var reg = new PrimaryRegistry(null);

        assertTrue(reg.nudgeTargetFor("term_worker").isEmpty(),
                "guessing would interrupt the wrong lead with someone else's result; the durable "
                        + "inbox makes pull the correct degradation");
    }

    @Test
    void releasingASessionForgetsItsLead() {
        var reg = new PrimaryRegistry(null);
        reg.recordDelegation("term_worker", "term_lead");

        reg.forgetDelegation("term_worker");

        assertTrue(reg.nudgeTargetFor("term_worker").isEmpty());
    }

    @Test
    void aBlankOrNullDelegationIsIgnoredRatherThanStored() {
        var reg = new PrimaryRegistry(null);
        reg.recordDelegation("term_worker", "  ");
        reg.recordDelegation(null, "term_lead");
        reg.recordDelegation("  ", "term_lead");

        assertTrue(reg.nudgeTargetFor("term_worker").isEmpty());
        assertTrue(reg.nudgeTargetFor(null).isEmpty());
    }
}