import XCTest
@testable import AIStudyApp

// MARK: - Mock services

private final class MockActivityService: ActivityServicing {
    var summary: ActivitySummary?
    var heatmap: [String: Int] = [:]
    var streak: ActivityStreak?
    var trends: [ActivityTrend] = []
    var recommendations: [ActivityRecommendation] = []

    func summary() async throws -> ActivitySummary { try resultOrThrow(summary) }
    func heatmap() async throws -> [String: Int] { heatmap }
    func streak() async throws -> ActivityStreak { try resultOrThrow(streak) }
    func trend(days: Int) async throws -> [ActivityTrend] { trends }
    func recommendations() async throws -> [ActivityRecommendation] { recommendations }
}

private final class MockFocusItemService: FocusItemServicing {
    var items: [FocusItem] = []
    func list() async throws -> [FocusItem] { items }
}

private final class MockReadingAPIForActivity: ReadingContinueServicing & LearningStatusServicing {
    var continueLearning: ContinueLearningResponse?
    var learningSummary: LearningSummaryResponse?
    var learningTrend: LearningTrendResponse?
    var records: LearningRecordsResponse?

    func getContinueLearning() async throws -> ContinueLearningResponse { try resultOrThrow(continueLearning) }
    func getLearningSummary() async throws -> LearningSummaryResponse { try resultOrThrow(learningSummary) }
    func getLearningTrend() async throws -> LearningTrendResponse { try resultOrThrow(learningTrend) }
    func getLearningRecords(limit: Int, type: String) async throws -> LearningRecordsResponse { try resultOrThrow(records) }
}

private func resultOrThrow<T>(_ value: T?) throws -> T {
    guard let v = value else { throw NSError(domain: "test", code: -1) }
    return v
}

// MARK: - Tests

@MainActor
final class ActivityViewModelTests: XCTestCase {

    var vm: ActivityViewModel!
    var mockActivity: MockActivityService!
    var mockFocus: MockFocusItemService!
    var mockReading: MockReadingAPIForActivity!

    override func setUp() {
        super.setUp()
        mockActivity = MockActivityService()
        mockFocus = MockFocusItemService()
        mockReading = MockReadingAPIForActivity()
        vm = ActivityViewModel(
            activityService: mockActivity,
            focusService: mockFocus,
            readingService: mockReading
        )
    }

    override func tearDown() {
        vm = nil
        super.tearDown()
    }

    // MARK: - Initial state

    func test_initial_isLoading_false() { XCTAssertFalse(vm.isLoading) }
    func test_initial_errorMessage_nil() { XCTAssertNil(vm.errorMessage) }
    func test_initial_summary_nil() { XCTAssertNil(vm.summary) }
    func test_initial_learningSummary_nil() { XCTAssertNil(vm.learningSummary) }
    func test_initial_readingTrend_nil() { XCTAssertNil(vm.readingTrend) }

    // MARK: - loadAll() basic

    func test_loadAll_sets_isLoading_false() async {
        await vm.loadAll()
        XCTAssertFalse(vm.isLoading)
    }

    func test_loadAll_sets_summary() async {
        mockActivity.summary = ActivitySummary(totalMinutes: 60, totalCardsReviewed: 10, activeDays: 5, dailyAverage: 12)
        await vm.loadAll()
        XCTAssertEqual(vm.summary?.activeDays, 5)
    }

    func test_loadAll_errorMessage_when_summary_nil() async {
        mockActivity.summary = nil
        await vm.loadAll()
        XCTAssertEqual(vm.errorMessage, "加载分析数据失败，请下拉刷新重试")
    }

    func test_loadAll_sets_focusItems() async {
        mockFocus.items = [FocusItem(id: "f1", userId: nil, knowledgeBaseId: nil, knowledgeItemId: nil, title: "Focus", reason: nil, suggestion: nil, priority: nil, status: "active", masteryScore: nil)]
        await vm.loadAll()
        XCTAssertEqual(vm.focusItems.count, 1)
    }

    func test_loadAll_sets_heatmap() async {
        mockActivity.heatmap = ["2026-01-01": 3]
        await vm.loadAll()
        XCTAssertEqual(vm.heatmap["2026-01-01"], 3)
    }

    func test_loadAll_sets_streak() async {
        mockActivity.streak = ActivityStreak(currentStreak: 5, longestStreak: 10, lastActiveDate: "2026-01-01")
        await vm.loadAll()
        XCTAssertEqual(vm.streak?.currentStreak, 5)
    }

    func test_loadAll_sets_trends() async {
        mockActivity.trends = [ActivityTrend(date: "2026-01-01", value: 8, label: "阅读")]
        await vm.loadAll()
        XCTAssertEqual(vm.trends.first?.label, "阅读")
    }

    func test_loadAll_sets_recommendations() async {
        mockActivity.recommendations = [ActivityRecommendation(title: "继续学习", description: nil, type: "study", priority: nil)]
        await vm.loadAll()
        XCTAssertEqual(vm.recommendations.first?.title, "继续学习")
    }

    // MARK: - loadAll() learningSummary / trend

    func test_loadAll_sets_learningSummary() async {
        mockReading.learningSummary = LearningSummaryResponse(
            todaySeconds: 120, weekSeconds: 600, totalSeconds: 3600,
            activeDays: 5, sessionsCount: 10, materialsReadCount: 3,
            markedReadCount: 1, dailyAverageSeconds: 600
        )
        await vm.loadAll()
        XCTAssertEqual(vm.learningSummary?.todaySeconds, 120)
        XCTAssertEqual(vm.learningSummary?.activeDays, 5)
    }

    func test_loadAll_sets_readingTrend() async {
        mockReading.learningTrend = LearningTrendResponse(
            days: 7,
            series: [LearningTrendResponse.TrendPoint(date: "2026-01-01", value: 100)]
        )
        await vm.loadAll()
        XCTAssertEqual(vm.readingTrend?.days, 7)
        XCTAssertEqual(vm.readingTrend?.series.first?.value, 100)
    }

    func test_loadAll_sets_continueReading() async {
        mockReading.continueLearning = ContinueLearningResponse(
            type: "knowledge_source", materialId: "m1", title: "Book",
            lastProgress: 0.5, totalActiveSeconds: 300, lastReadAt: "2026-01-01"
        )
        await vm.loadAll()
        XCTAssertEqual(vm.continueReading?.materialId, "m1")
    }

    func test_loadAll_sets_recentRecords() async {
        mockReading.records = LearningRecordsResponse(items: [
            LearningRecordsResponse.RecordItem(id: "r1", recordType: "reading", title: "Rec1", description: nil, durationSeconds: 120, occurredAt: "2026-01-01")
        ], nextCursor: nil)
        await vm.loadAll()
        XCTAssertEqual(vm.recentRecords.count, 1)
        XCTAssertEqual(vm.recentRecords.first?.title, "Rec1")
    }

    func test_loadAll_learningSummary_nil_on_error() async {
        mockReading.learningSummary = nil
        await vm.loadAll()
        XCTAssertNil(vm.learningSummary)
    }

    // MARK: - refresh()

    func test_refresh_clears_errorMessage() async {
        vm.errorMessage = "old error"
        mockActivity.summary = ActivitySummary(totalMinutes: 0, totalCardsReviewed: 0, activeDays: 0, dailyAverage: 0)
        await vm.refresh()
        XCTAssertNil(vm.errorMessage)
    }
}