package com.gzzn.omms.msgexchange.delivery

import com.gzzn.omms.msgexchange.MutableClock
import com.gzzn.omms.msgexchange.config.PipelineProps
import com.gzzn.omms.msgexchange.domain.ErrorClass
import com.gzzn.omms.msgexchange.domain.EventStatus
import com.gzzn.omms.msgexchange.domain.MsgEvent
import com.gzzn.omms.msgexchange.domain.Targets
import com.gzzn.omms.msgexchange.infra.persistence.MsgEventRepository
import com.gzzn.omms.msgexchange.infra.retry.FailureScheduler
import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Assertions.assertNotNull
import org.junit.jupiter.api.Assertions.assertNull
import org.junit.jupiter.api.Assertions.assertTrue
import org.junit.jupiter.api.Test
import java.time.Instant

/**
 * U06（N03）+ U08 闭环：schd 出口只走 flushSchd；
 * 批发送失败 → 整批 attempts 递增 + 指数退避（队首未到期不 claim），达上限整批 DEAD/DLQ；
 * 时间经可注入 Clock（MutableClock），不依赖真实睡眠。
 */
class DispatcherTickTest {

    private class FakeRepo : MsgEventRepository {
        val events = mutableListOf<MsgEvent>()

        fun enqueue(e: MsgEvent) { events += e }

        override fun insertAll(events: List<MsgEvent>) = events.map { it.eventId ?: 0L }

        override fun headUnsent(target: String): MsgEvent? =
            events.filter { it.target == target && it.state != EventStatus.SENT && it.state != EventStatus.DEAD }
                .minByOrNull { it.eventId ?: Long.MAX_VALUE }

        override fun claimBatch(target: String, limit: Int): List<MsgEvent> =
            events.filter { it.target == target && it.state == EventStatus.PENDING }
                .sortedBy { it.eventId ?: Long.MAX_VALUE }
                .take(limit)

        override fun markSent(eventId: Long) {
            val i = events.indexOfFirst { it.eventId == eventId }
            if (i >= 0) events[i] = events[i].copy(state = EventStatus.SENT)
        }

        override fun markAllSent(eventIds: List<Long>) = eventIds.forEach(::markSent)

        override fun scheduleRetry(eventId: Long, nextAttemptAt: Instant, attempts: Int) {
            val i = events.indexOfFirst { it.eventId == eventId }
            if (i >= 0) events[i] = events[i].copy(state = EventStatus.PENDING, attempts = attempts, nextAttemptAt = nextAttemptAt)
        }

        override fun markDead(eventId: Long, errorClass: ErrorClass, lastError: String, attempts: Int?) {
            val i = events.indexOfFirst { it.eventId == eventId }
            if (i >= 0) events[i] = events[i].copy(state = EventStatus.DEAD, errorClass = errorClass, lastError = lastError,
                attempts = attempts ?: events[i].attempts)
        }

        override fun insertSync(events: List<MsgEvent>) { syncInserted += events }

        val syncInserted = mutableListOf<MsgEvent>()
    }

    private class FakePort : DeliveryPort {
        val sent = mutableListOf<Pair<String, String>>()
        var failTopic: String? = null

        override fun sendKafka(topic: String, payloadJson: String) {
            if (failTopic == topic) throw RuntimeException("send-fail:$topic")
            sent += topic to payloadJson
        }

        override fun indexFlightHts(payloadJson: String) = Unit
    }

    private val clock = MutableClock(MutableClock.BASE)

    private fun dispatcher(repo: FakeRepo, port: FakePort, p: PipelineProps = PipelineProps()): Dispatcher =
        Dispatcher(repo, port, p, FailureScheduler(p, clock))

    private fun ev(id: Long, target: String, key: String?, payload: String) =
        MsgEvent(eventId = id, target = target, partitionKey = key, payloadJson = payload, state = EventStatus.PENDING)

    @Test
    fun `schd flushed once via batch path, per-target tick never consumes it`() {
        val repo = FakeRepo()
        val port = FakePort()
        val d = dispatcher(repo, port)
        repo.enqueue(ev(1, Targets.KAFKA_MSG, null, """{"msg":1}"""))
        repo.enqueue(ev(2, Targets.KAFKA_SCHD, "F1", """{"FLID":"F1","v":1}"""))

        d.tick()   // lastFlush=EPOCH → 首 tick 即到 flush 周期

        assertEquals(1, port.sent.count { it.first == "msg" })
        assertEquals(1, port.sent.count { it.first == "schd" })
        assertEquals(EventStatus.SENT, repo.events.first { it.eventId == 2L }.state)

        repo.enqueue(ev(4, Targets.KAFKA_SCHD, "F1", """{"FLID":"F1","v":4}"""))
        d.tick()   // 时钟未推进 → flush 周期未到；逐条循环不得消费 schd
        assertEquals(EventStatus.PENDING, repo.events.first { it.eventId == 4L }.state)
        assertEquals(1, port.sent.count { it.first == "schd" })
    }

    @Test
    fun `flushSchd aggregates latest per flight and marks all sent`() {
        val repo = FakeRepo()
        val port = FakePort()
        val d = dispatcher(repo, port)
        repo.enqueue(ev(1, Targets.KAFKA_SCHD, "F1", "old"))
        repo.enqueue(ev(2, Targets.KAFKA_SCHD, "F2", "only"))
        repo.enqueue(ev(3, Targets.KAFKA_SCHD, "F1", "new"))

        d.flushSchd()

        val payload = port.sent.first { it.first == "schd" }.second
        assertTrue(payload.contains("new") && payload.contains("only") && !payload.contains("old"))
        assertEquals(2, payload.removeSurrounding("[", "]").split(",").size)   // 同 FLID 只发最新（矩阵 #7）
        assertTrue(repo.events.all { it.state == EventStatus.SENT })
    }

    @Test
    fun `flush failure schedules per-event backoff and retries after due`() {
        val repo = FakeRepo()
        val port = FakePort().apply { failTopic = "schd" }
        val d = dispatcher(repo, port)
        repo.enqueue(ev(1, Targets.KAFKA_SCHD, "F1", """{"v":"1"}"""))

        d.flushSchd()
        val e1 = repo.events.single()
        assertEquals(EventStatus.PENDING, e1.state)
        assertEquals(1, e1.attempts)
        assertNotNull(e1.nextAttemptAt)                 // 指数退避落库（attempts=1 → 首档）
        assertEquals(0, port.sent.size)

        clock.advance(1000)                             // 退避到期
        port.failTopic = null
        d.flushSchd()
        assertEquals(EventStatus.SENT, repo.events.single().state)
        assertEquals(1, port.sent.count { it.first == "schd" })
    }

    @Test
    fun `repeated batch failures backoff grows and whole batch goes DEAD DLQ at limit`() {
        val props = PipelineProps().apply { pipeline.maxAttempts = 2 }
        val repo = FakeRepo()
        val port = FakePort().apply { failTopic = "schd" }
        val d = dispatcher(repo, port, props)
        repo.enqueue(ev(1, Targets.KAFKA_SCHD, "F1", """{"v":"1"}"""))
        repo.enqueue(ev(2, Targets.KAFKA_SCHD, "F2", """{"v":"2"}"""))

        d.flushSchd()                                   // 失败#1：attempts=1，退避 backoff[1]=1000ms
        val after1 = repo.events.map { it.attempts to it.state }
        assertEquals(listOf(1 to EventStatus.PENDING, 1 to EventStatus.PENDING), after1)
        assertTrue(repo.events.all { it.nextAttemptAt == MutableClock.BASE.plusMillis(1000) })

        d.flushSchd()                                   // 时钟未推进 → 队首未到期，不 claim（不推进 lastFlush）
        assertEquals(1, repo.events.first { it.eventId == 1L }.attempts)

        clock.advance(1000)
        d.flushSchd()                                   // 失败#2：attempts=2 == maxAttempts → 整批 DEAD
        assertTrue(repo.events.all { it.state == EventStatus.DEAD && it.errorClass == ErrorClass.EXHAUSTED })
        assertTrue(repo.events.all { it.attempts == 2 })
        assertEquals(0, port.sent.size)

        // DEAD 行不再参与 claim：空批 → 无新发送、无异常
        d.flushSchd()
        assertEquals(0, port.sent.size)
    }

    @Test
    fun `KAFKA msg delivery unaffected while schd batch is retrying`() {
        val props = PipelineProps().apply { pipeline.maxAttempts = 2 }
        val repo = FakeRepo()
        val port = FakePort().apply { failTopic = "schd" }
        val d = dispatcher(repo, port, props)
        repo.enqueue(ev(1, Targets.KAFKA_SCHD, "F1", """{"v":"1"}"""))
        repo.enqueue(ev(2, Targets.KAFKA_MSG, null, """{"m":1}"""))

        d.tick()

        assertEquals(EventStatus.SENT, repo.events.first { it.eventId == 2L }.state)   // msg 正常
        assertEquals(1, repo.events.first { it.eventId == 1L }.attempts)               // schd 进退避
        assertEquals(EventStatus.PENDING, repo.events.first { it.eventId == 1L }.state)
    }

}