package com.peachpasswords.sync

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

/**
 * The indicator light is the whole point of this vocabulary, so the mapping is
 * swept exhaustively rather than sampled: a reason added later has to be given
 * a place here or the sweep fails.
 */
class SyncOutcomeTest {

    private val succeeded = setOf(
        SyncOutcomeReason.COMPLETED_CHANGES,
        SyncOutcomeReason.COMPLETED_NO_CHANGES,
    )

    @Test fun `only a real success is ever green, even with devices paired`() {
        for (reason in SyncOutcomeReason.entries) {
            val indicator = syncIndicator(SyncOutcomeSummary(reason = reason), pairedCount = 5)
            if (reason in succeeded) {
                assertEquals("$reason must be ok", SyncIndicator.OK, indicator)
            } else {
                assertNotEquals("$reason must never resolve to ok", SyncIndicator.OK, indicator)
            }
        }
    }

    /**
     * The set itself, not just its self-consistency with the light: moving a
     * reason out of it would otherwise flip red to unlit with every other test
     * still green. "Paired, but nothing here can accept a sync" in particular
     * is a problem, not a quiet state.
     */
    @Test fun `the failing outcomes are exactly these`() {
        assertEquals(
            setOf(
                SyncOutcomeReason.NO_ELIGIBLE_HOST,
                SyncOutcomeReason.VAULT_LOCKED,
                SyncOutcomeReason.RELAY_UNREACHABLE,
                SyncOutcomeReason.HANDSHAKE_FAILED,
                SyncOutcomeReason.VAULT_ID_MISMATCH,
                SyncOutcomeReason.SYNC_TIMEOUT,
                SyncOutcomeReason.RUN_FAILED,
            ),
            SyncOutcomeReason.entries.filter { it.isFailure }.toSet(),
        )
    }

    @Test fun `every failure is red and nothing else is`() {
        for (reason in SyncOutcomeReason.entries) {
            val indicator = syncIndicator(SyncOutcomeSummary(reason = reason), pairedCount = 1)
            assertEquals(
                "$reason: isFailure and the red light must agree",
                reason.isFailure,
                indicator == SyncIndicator.ERROR,
            )
        }
    }

    @Test fun `a run in flight pulses whatever the last outcome was`() {
        for (reason in SyncOutcomeReason.entries + null) {
            assertEquals(
                SyncIndicator.BUSY,
                syncIndicator(SyncOutcomeSummary(reason = reason, syncing = true), pairedCount = 0),
            )
        }
    }

    @Test fun `a successful pair with nothing attempted is green, and nothing paired is unlit`() {
        assertEquals(SyncIndicator.OK, syncIndicator(SyncOutcomeSummary(), pairedCount = 1))
        assertEquals(SyncIndicator.IDLE, syncIndicator(SyncOutcomeSummary(), pairedCount = 0))
        // Paired but switched off is not a problem and not health — unlit.
        assertEquals(
            SyncIndicator.IDLE,
            syncIndicator(SyncOutcomeSummary(reason = SyncOutcomeReason.SYNC_DISABLED), pairedCount = 1),
        )
    }

    @Test fun `a sync that could not run reads differently from one that found nothing`() {
        val ranAndFoundNothing = describeSyncOutcome(
            SyncOutcomeSummary(reason = SyncOutcomeReason.COMPLETED_NO_CHANGES),
        )
        val couldNotRun = describeSyncOutcome(
            SyncOutcomeSummary(reason = SyncOutcomeReason.NO_ELIGIBLE_HOST, detail = "Pixel [type=android]"),
        )
        assertEquals("Up to date — nothing to send or receive", ranAndFoundNothing)
        assertEquals(
            "Paired, but no device here can accept a sync (Pixel [type=android])",
            couldNotRun,
        )
    }

    /** Word for word the browser's `COPY` table — the two clients sit side by side. */
    @Test fun `copy matches the browser`() {
        fun copy(reason: SyncOutcomeReason) = describeSyncOutcome(SyncOutcomeSummary(reason = reason))
        assertEquals("Not synced yet", describeSyncOutcome(SyncOutcomeSummary()))
        assertEquals("Synced", copy(SyncOutcomeReason.COMPLETED_CHANGES))
        assertEquals("Up to date — nothing to send or receive", copy(SyncOutcomeReason.COMPLETED_NO_CHANGES))
        assertEquals("No devices paired yet", copy(SyncOutcomeReason.NO_PAIRED_DEVICES))
        assertEquals("Paired, but no device here can accept a sync", copy(SyncOutcomeReason.NO_ELIGIBLE_HOST))
        assertEquals("Sync is switched off", copy(SyncOutcomeReason.SYNC_DISABLED))
        assertEquals("Vault was locked — unlock and sync again", copy(SyncOutcomeReason.VAULT_LOCKED))
        assertEquals("Couldn't reach the relay", copy(SyncOutcomeReason.RELAY_UNREACHABLE))
        assertEquals("Reached the relay, but the device didn't answer", copy(SyncOutcomeReason.HANDSHAKE_FAILED))
        assertEquals("That device holds a different vault", copy(SyncOutcomeReason.VAULT_ID_MISMATCH))
        assertEquals("The device stopped responding mid-sync", copy(SyncOutcomeReason.SYNC_TIMEOUT))
        assertEquals("Sync failed", copy(SyncOutcomeReason.RUN_FAILED))
    }

    @Test fun `a completed sync says what moved`() {
        assertEquals(
            "Synced — 3 sent, 1 received",
            describeSyncOutcome(
                SyncOutcomeSummary(
                    reason = SyncOutcomeReason.COMPLETED_CHANGES,
                    entriesSent = 3,
                    entriesReceived = 1,
                ),
            ),
        )
    }

    @Test fun `the label always carries the colour's claim in words`() {
        assertEquals(
            "Sync problem — Couldn't reach the relay",
            syncIndicatorLabel(
                SyncIndicator.ERROR,
                SyncOutcomeSummary(reason = SyncOutcomeReason.RELAY_UNREACHABLE),
            ),
        )
        assertEquals("Not syncing — Not synced yet", syncIndicatorLabel(SyncIndicator.IDLE, SyncOutcomeSummary()))
        assertTrue(syncIndicatorLabel(SyncIndicator.BUSY, SyncOutcomeSummary()).startsWith("Syncing"))
        assertTrue(syncIndicatorLabel(SyncIndicator.OK, SyncOutcomeSummary()).startsWith("Sync healthy"))
    }

    @Test fun `opaque session errors are classified, not lumped into one failure`() {
        assertEquals(SyncOutcomeReason.VAULT_LOCKED, classifySyncError("VAULT_LOCKED"))
        assertEquals(SyncOutcomeReason.VAULT_ID_MISMATCH, classifySyncError("vault_id_mismatch"))
        assertEquals(SyncOutcomeReason.SYNC_TIMEOUT, classifySyncError("session timed out after 30s"))
        assertEquals(
            SyncOutcomeReason.HANDSHAKE_FAILED,
            classifySyncError("peer identity does not match authenticated KK key"),
        )
        assertEquals(
            SyncOutcomeReason.HANDSHAKE_FAILED,
            classifySyncError("reconnect capability does not match relay room"),
        )
        assertEquals(SyncOutcomeReason.RELAY_UNREACHABLE, classifySyncError("relay_closed_1006"))
        assertEquals(SyncOutcomeReason.RUN_FAILED, classifySyncError("something nobody predicted"))
    }

    @Test fun `a session outcome becomes the user-facing one`() {
        assertEquals(
            SyncOutcomeReason.COMPLETED_NO_CHANGES,
            SyncOutcome(SyncOutcomeStatus.COMPLETED).toSummary().reason,
        )
        assertEquals(
            SyncOutcomeReason.COMPLETED_CHANGES,
            SyncOutcome(SyncOutcomeStatus.COMPLETED, entriesReceived = 2).toSummary().reason,
        )
        // A deletion that crossed the wire is a change, not "nothing to do".
        assertEquals(
            SyncOutcomeReason.COMPLETED_CHANGES,
            SyncOutcome(SyncOutcomeStatus.COMPLETED, tombstonesSent = 1).toSummary().reason,
        )
        assertEquals(
            SyncOutcomeReason.VAULT_ID_MISMATCH,
            SyncOutcome(SyncOutcomeStatus.VAULT_MISMATCH).toSummary().reason,
        )
        assertEquals(
            SyncOutcomeReason.SYNC_TIMEOUT,
            SyncOutcome(SyncOutcomeStatus.TIMEOUT, error = "session timed out after 30s").toSummary().reason,
        )
        assertEquals(
            SyncOutcomeReason.RELAY_UNREACHABLE,
            SyncOutcome(SyncOutcomeStatus.ERRORED, error = "relay_receive_queue_full").toSummary().reason,
        )
    }

    @Test fun `the reason for a failure survives being killed`() {
        val failure = SyncOutcomeSummary(
            reason = SyncOutcomeReason.HANDSHAKE_FAILED,
            detail = "peer identity does not match authenticated KK key",
            entriesSent = 4,
            entriesReceived = 2,
            finishedAt = 1_700_000_000_000L,
        )
        assertEquals(failure, decodeSyncOutcome(encodeSyncOutcome(failure)))
    }

    @Test fun `a process killed mid-sync does not come back claiming to be syncing`() {
        val inFlight = SyncOutcomeSummary(reason = SyncOutcomeReason.COMPLETED_CHANGES, syncing = true)
        val restored = decodeSyncOutcome(encodeSyncOutcome(inFlight))
        assertEquals(false, restored.syncing)
        assertEquals(SyncOutcomeReason.COMPLETED_CHANGES, restored.reason)
    }

    @Test fun `nothing stored, or something unreadable, restores as nothing attempted`() {
        assertNull(decodeSyncOutcome(null).reason)
        assertNull(decodeSyncOutcome("{not json").reason)
        assertNull(decodeSyncOutcome("""{"reason":"A_REASON_FROM_THE_FUTURE"}""").reason)
    }
}