namespace LivingVillage.Desktop.Tests

open Microsoft.VisualStudio.TestTools.UnitTesting
open LivingVillage.Desktop

/// P57 美术 A3：菜单/启动水面第二层高光波光（P46 遗留短板）。
///
/// 高光层必须与主水带**可分辨**：更亮更窄、列相位错开、推进速度略不同；
/// 全为帧计数纯函数（无随机），且**不得改变**既有 waterPhase / lantern / 云影输出。
[<TestClass>]
type P57MenuHighlightTests () =

    let twoPi = 2.0f * float32 System.Math.PI
    let assertClose (expected: float32) (actual: float32) (message: string) =
        Assert.IsTrue((abs (expected - actual) < 1e-4f), sprintf "%s: expected %f actual %f" message expected actual)
    let assertInt (expected: int) (actual: int) (message: string) =
        Assert.IsTrue((expected = actual), sprintf "%s: expected %d actual %d" message expected actual)

    let visibleColumn (frame: int64) (rowIndex: int) : int =
        [ 0 .. 63 ]
        |> List.tryFind (fun column -> MenuAmbience.highlightVisible frame column rowIndex)
        |> Option.defaultValue -1

    [<TestMethod>]
    member _.HighlightPhaseOffsetsAdjacentColumnsByANonZeroStep () =
        for frame in [ 0L; 16L; 150L; 4097L ] do
            for rowIndex in [ 0; 1 ] do
                for column in [ 0; 5; 21; 38 ] do
                    let step =
                        MenuAmbience.highlightPhase frame (column + 1) rowIndex
                        - MenuAmbience.highlightPhase frame column rowIndex
                    assertClose MenuAmbience.highlightColumnStep step (sprintf "frame %d col %d row %d" frame column rowIndex)
                    Assert.IsTrue(abs step > 1e-3f, "adjacent highlight columns must be phase-shifted")

    [<TestMethod>]
    member _.HighlightMovesAtADifferentSpeedThanTheMainWaterBand () =
        // 主水带连续相位速率 = (2π/3)/32；高光层 = 2π/period，二者比值应略偏离 1（本实现 1.2）。
        let mainDelta =
            MenuAmbience.waterPhase 151L 5 0 - MenuAmbience.waterPhase 150L 5 0
        let highlightDelta =
            MenuAmbience.highlightPhase 151L 5 0 - MenuAmbience.highlightPhase 150L 5 0
        Assert.IsTrue(highlightDelta > 0.0f && mainDelta > 0.0f, "both layers must advance with the frame")
        let ratio = highlightDelta / mainDelta
        assertClose 1.2f ratio "highlight speed must be slightly different (1.2x)"
        Assert.IsTrue(abs (highlightDelta - mainDelta) > 1e-3f, "the two layers must not move at the same speed")

    [<TestMethod>]
    member _.HighlightLayerIsBrighterAndNarrowerThanTheMainBand () =
        // 更窄：条更薄、更短。
        Assert.IsTrue(MenuAmbience.highlightThickness < 3, "highlight bar must be thinner than the 3px main crest")
        Assert.IsTrue(MenuAmbience.highlightBarWidth < 32, "highlight bar must be narrower than a tile")
        // 更亮：纯白高光 > 主水带波峰色 (225,240,245) 的 luma。
        let r, g, b = MenuAmbience.highlightRgb
        let highlightLuma = 0.299f * float32 r + 0.587f * float32 g + 0.114f * float32 b
        let crestLuma = 0.299f * 225.0f + 0.587f * 240.0f + 0.114f * 245.0f
        Assert.IsTrue(highlightLuma > crestLuma, sprintf "highlight luma %.1f must exceed crest luma %.1f" highlightLuma crestLuma)
        // 更窄的可见条件（阈值更高 → 亮列更稀疏），但仍有可见列。
        let frame = 150L
        let highlightCount = [ 0 .. 39 ] |> List.filter (fun c -> MenuAmbience.highlightVisible frame c 0) |> List.length
        let mainCount = [ 0 .. 39 ] |> List.filter (fun c -> MenuAmbience.waterColumnCrest frame c 0) |> List.length
        Assert.IsTrue(highlightCount > 0, "some highlight columns must be lit")
        Assert.IsTrue(highlightCount <= mainCount, sprintf "highlight %d must be no denser than main crest %d" highlightCount mainCount)

    [<TestMethod>]
    member _.HighlightIsDeterministicAndBounded () =
        for frame in [ 0L; 1L; 33L; 173L; 99999L; 100000L; 500000L ] do
            for column in [ 0; 13; 39 ] do
                for rowIndex in [ 0; 1 ] do
                    assertClose
                        (MenuAmbience.highlightPhase frame column rowIndex)
                        (MenuAmbience.highlightPhase frame column rowIndex)
                        "highlight phase must be deterministic"
                    let alpha = MenuAmbience.highlightAlpha MenuAmbience.highlightDayLight frame column rowIndex
                    Assert.IsTrue(alpha >= 0 && alpha <= 255, sprintf "alpha %d out of [0,255]" alpha)

    [<TestMethod>]
    member _.NightLightDimmsTheHighlightButKeepsItReadable () =
        let frame = 150L
        let column = visibleColumn frame 0
        Assert.IsTrue(column >= 0, "need a lit column to compare day/night")
        let day = MenuAmbience.highlightAlpha MenuAmbience.highlightDayLight frame column 0
        let night = MenuAmbience.highlightAlpha MenuAmbience.highlightNightLight frame column 0
        Assert.IsTrue(night < day, sprintf "night alpha %d must be below day %d" night day)
        Assert.IsTrue(night >= int (0.35f * float32 day), sprintf "night alpha %d must stay readable (>= 35%% of day)" night)
        Assert.IsTrue(night >= 20, sprintf "night alpha %d must not vanish" night)

    [<TestMethod>]
    member _.ExistingWaterLanternCloudOutputsArePinned () =
        // 回归：高光层不得改变既有 waterPhase / lantern / 云影输出帧。
        assertInt 0 (VillageArt.waterFrameTickAt 150L 5 0) "waterFrameTickAt pin"
        assertClose 1.317237f (MenuAmbience.waterColumnBrightness 150L 5 0) "main water brightness pin"
        assertInt 89 (MenuAmbience.lanternBreathAlpha 50L 0) "lantern breath pin"
        assertInt 70 (MenuAmbience.cloudOffsetPx 0 140L 1280) "cloud offset pin"
        Assert.AreEqual<int list>([ 624; 656 ], (TitleScreen.layout 1280 720).WaterRows)

    [<TestMethod>]
    member _.P57ShotScriptWaterFramesAreOrderedAndDistinct () =
        Assert.IsTrue(P57ShotScript.splashFrame > 0L && P57ShotScript.splashFrame < LaunchScreen.durationFrames)
        Assert.IsTrue(P57ShotScript.menuFrame >= 120L, "menu frame must wait for the entrance to settle")
        let names =
            [ P57ShotScript.splashBaseName
              P57ShotScript.splashHighlightName
              P57ShotScript.menuBaseName
              P57ShotScript.menuHighlightName ]
        assertInt names.Length (names |> List.distinct |> List.length) "shot names distinct"