import Testing
@testable import MusubiCore

@Suite struct DisplayModeSelectionTests {
    let current = DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 1920, pixelHeight: 1080, refreshRate: 60)

    @Test func picksSameSizeAt50Hz() {
        let modes = [
            current,
            DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 1920, pixelHeight: 1080, refreshRate: 50),
            DisplayModeInfo(width: 1280, height: 720, pixelWidth: 1280, pixelHeight: 720, refreshRate: 50),
        ]
        #expect(DisplayModeSelection.mode(matching: 50, current: current, available: modes)?.refreshRate == 50)
        #expect(DisplayModeSelection.mode(matching: 50, current: current, available: modes)?.width == 1920)
    }

    @Test func prefersSameBackingResolution() {
        let hidpi = DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 3840, pixelHeight: 2160, refreshRate: 60)
        let modes = [
            DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 1920, pixelHeight: 1080, refreshRate: 50),
            DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 3840, pixelHeight: 2160, refreshRate: 50),
        ]
        #expect(DisplayModeSelection.mode(matching: 50, current: hidpi, available: modes)?.pixelWidth == 3840)
    }

    @Test func nilWhenAlreadyAt50HzOrUnavailable() {
        let at50 = DisplayModeInfo(width: 1920, height: 1080, pixelWidth: 1920, pixelHeight: 1080, refreshRate: 50)
        #expect(DisplayModeSelection.mode(matching: 50, current: at50, available: [at50]) == nil)
        #expect(DisplayModeSelection.mode(matching: 50, current: current, available: [current]) == nil)
    }
}

@Suite struct FrameStatsTests {
    // 50 fps → 200_000 ticks per frame.
    let frame: Int64 = 200_000

    @Test func countsGapsAsMissingFrames() {
        var stats = FrameStats()
        stats.record(timestamp: 0, frameRateN: 50, frameRateD: 1)
        stats.record(timestamp: frame, frameRateN: 50, frameRateD: 1)
        stats.record(timestamp: frame * 4, frameRateN: 50, frameRateD: 1) // 2 frames missing
        #expect(stats.received == 3)
        #expect(stats.missing == 2)
        #expect(stats.lossRate == 0.4)
    }

    @Test func toleratesJitter() {
        var stats = FrameStats()
        stats.record(timestamp: 0, frameRateN: 50, frameRateD: 1)
        stats.record(timestamp: frame + frame / 4, frameRateN: 50, frameRateD: 1)
        #expect(stats.missing == 0)
    }

    @Test func outageIsNotCountedAsLoss() {
        var stats = FrameStats()
        stats.record(timestamp: 0, frameRateN: 50, frameRateD: 1)
        stats.record(timestamp: 50_000_000, frameRateN: 50, frameRateD: 1) // 5 s later
        #expect(stats.missing == 0)
    }

    @Test func includesFramesDroppedByReceiver() {
        var stats = FrameStats()
        for i in 0..<998 { stats.record(timestamp: Int64(i) * frame, frameRateN: 50, frameRateD: 1) }
        stats.updateDroppedByReceiver(2)
        #expect(stats.lossRate == 0.002)
    }

    @Test func handlesNTSCRates() {
        var stats = FrameStats()
        let ticks = Int64((1001.0 / 30000.0 * FrameStats.ticksPerSecond).rounded())
        stats.record(timestamp: 0, frameRateN: 30000, frameRateD: 1001)
        stats.record(timestamp: ticks * 3, frameRateN: 30000, frameRateD: 1001)
        #expect(stats.missing == 2)
    }
}

@Suite struct ConnectionWatchdogTests {
    @Test func connectingThenLive() {
        var dog = ConnectionWatchdog(now: 0)
        #expect(dog.state(at: 1) == .connecting)
        dog.frameArrived(at: 1)
        #expect(dog.state(at: 1.5) == .live)
    }

    @Test func stallsAndRetriesEveryInterval() {
        var dog = ConnectionWatchdog(now: 0)
        dog.frameArrived(at: 10)
        #expect(dog.state(at: 11.9) == .live)
        #expect(dog.state(at: 12) == .stalled(retryIn: 3))
        let retry1 = dog.shouldRetry(at: 13)
        #expect(!retry1)
        let retry2 = dog.shouldRetry(at: 15)
        #expect(retry2)
        #expect(dog.state(at: 16) == .stalled(retryIn: 2))
        let retry3 = dog.shouldRetry(at: 18)
        #expect(retry3)
    }

    @Test func recoversWhenFramesReturn() {
        var dog = ConnectionWatchdog(now: 0)
        dog.frameArrived(at: 0)
        let retry4 = dog.shouldRetry(at: 5)
        #expect(retry4)
        dog.frameArrived(at: 6)
        #expect(dog.state(at: 6.5) == .live)
    }

    @Test func neverConnectedSourceAlsoRetries() {
        var dog = ConnectionWatchdog(now: 0)
        let retry5 = dog.shouldRetry(at: 5)
        #expect(retry5)
    }
}

@Suite struct RouteArgumentTests {
    @Test func parsesRoutes() {
        let args = ["Musubi", "--route", "ZOWIEBOX (PGM)=1", "-NSFoo", "YES", "--route", "MV=0"]
        #expect(RouteArgument.parse(args) == [
            .init(ndiName: "ZOWIEBOX (PGM)", screenIndex: 1),
            .init(ndiName: "MV", screenIndex: 0),
        ])
    }

    @Test func ignoresMalformed() {
        #expect(RouteArgument.parse(["--route", "noindex", "--route", "=1", "--route", "A=-1", "--route"]).isEmpty)
    }
}