import XCTest
@testable import AIStudyApp

final class ExportQueueAckTests: XCTestCase {

    // MARK: - Pipeline: export → enqueue

    func test_exportAndEnqueue_pipeline_exists() {
        let pipeline = ReadingEventUploadPipeline.shared
        XCTAssertNotNil(pipeline)
    }

    // MARK: - Queue: enqueue + pending count

    func test_queue_enqueue_increases_pending_count() {
        let queue = ReadingEventUploadQueue.shared
        let before = queue.pendingCount

        let item = ReadingEventUploadItem(
            eventId: "evt-e2a-001",
            clientSessionId: "sess-001",
            materialId: "mat-001",
            eventType: "material_opened",
            position: nil,
            activeSecondsDelta: 0,
            clientTimestampMs: 1_700_000_000_000,
            sequence: 1,
            readingTargetType: "knowledge_source",
            knowledgeBaseId: nil,
            platform: "ios",
            appVersion: "1.0.0",
            clientTimezoneOffsetMinutes: 480
        )
        queue.enqueue([item])
        let after = queue.pendingCount
        XCTAssertGreaterThanOrEqual(after, before, "Enqueue should not decrease pending count")

        // Cleanup
        queue.markPermanentFailed(ids: [item.eventId], errorCode: "TEST_CLEANUP")
    }

    // MARK: - Queue: mark uploaded

    func test_queue_mark_uploaded_removes_from_pending() {
        let queue = ReadingEventUploadQueue.shared
        let item = ReadingEventUploadItem(
            eventId: "evt-e2a-002",
            clientSessionId: "sess-002",
            materialId: "mat-002",
            eventType: "heartbeat",
            position: nil,
            activeSecondsDelta: 15,
            clientTimestampMs: 1_700_000_000_000,
            sequence: 2,
            readingTargetType: "temporary_file",
            knowledgeBaseId: nil,
            platform: "ios",
            appVersion: "1.0.0",
            clientTimezoneOffsetMinutes: 480
        )
        queue.enqueue([item])
        queue.markUploading(ids: [item.eventId])
        queue.markUploaded(ids: [item.eventId])

        // After markUploaded, item should not be pending
        let pending = queue.fetchPendingBatch(limit: 10)
        let stillPending = pending.contains { $0.eventId == item.eventId }
        XCTAssertFalse(stillPending, "Marked-uploaded item should not be in pending batch")
    }

    // MARK: - Queue: mark retry

    func test_queue_mark_retry_keeps_item_pending() {
        let queue = ReadingEventUploadQueue.shared
        let item = ReadingEventUploadItem(
            eventId: "evt-e2a-003",
            clientSessionId: "sess-003",
            materialId: "mat-003",
            eventType: "position_changed",
            position: nil,
            activeSecondsDelta: 0,
            clientTimestampMs: 1_700_000_000_000,
            sequence: 3,
            readingTargetType: "knowledge_source",
            knowledgeBaseId: nil,
            platform: "ios",
            appVersion: "1.0.0",
            clientTimezoneOffsetMinutes: 480
        )
        queue.enqueue([item])
        queue.markRetry(ids: [item.eventId])

        // Cleanup
        queue.clearAll()
    }

    // MARK: - Ack idempotency

    func test_ack_idempotent() {
        let adapter = NoopReadingRuntimeAdapter()
        // Ack should return the count even for non-existent events
        let count1 = adapter.ackEvents(["evt-fake-1", "evt-fake-2"])
        let count2 = adapter.ackEvents(["evt-fake-1", "evt-fake-2"])
        XCTAssertEqual(count1, count2, "Repeated ack should return same count (idempotent)")
    }

    // MARK: - Adapter: export + ack + markFailed

    func test_noop_adapter_export_returns_empty() {
        let adapter = NoopReadingRuntimeAdapter()
        let events = adapter.exportEvents(limit: 100, timestampMs: 1_700_000_000_000)
        XCTAssertTrue(events.isEmpty, "Noop adapter should return empty export")
    }

    func test_noop_adapter_mark_failed_returns_count() {
        let adapter = NoopReadingRuntimeAdapter()
        let count = adapter.markFailed(["evt-f1", "evt-f2", "evt-f3"])
        XCTAssertEqual(count, 3)
    }
}