namespace LivingVillage.Desktop

open Microsoft.Xna.Framework
open LivingVillage.Kernel
open LivingVillage.Kernel.Sim

/// 顶部窄信息条 HUD 的纯布局/配色模型：只做确定性计算，实际绘制在 Game.fs。
/// 常驻状态（时段/时间/倍速/体力/钱币）压进一条窄带，绝不用整屏纯色或大黑块。
module HudLayout =

    let barHeight = 36
    let accentHeight = 3
    let paddingX = 16
    let segmentGap = 20
    let textScale = 2

    /// 常驻段的像素图标（7x7 点阵，按 iconScale 放大），全部用 pixel 贴图绘制、无外部素材。
    type HudIcon =
        | PeriodIcon
        | ClockIcon
        | SpeedIcon
        | EnergyIcon
        | MoneyIcon

    type Segment =
        { Label: string
          Value: string
          Icon: HudIcon }

    let segmentText (segment: Segment) : string = sprintf "%s %s" segment.Label segment.Value

    /// 常驻状态片段，数值全部取自世界真实状态，绝不编造。
    let segments (world: World) (control: SimulationControl) : Segment list =
        let needs = world.Avatar.Mind.Needs
        [ { Label = "时段"; Value = M6Presentation.timePeriodLabel world.Tick; Icon = PeriodIcon }
          { Label = "时间"; Value = M6Presentation.clockTimeLabel world.Tick; Icon = ClockIcon }
          { Label = "倍速"; Value = M6Presentation.speedLabel control; Icon = SpeedIcon }
          { Label = "体力"; Value = sprintf "%.0f" needs.Energy; Icon = EnergyIcon }
          { Label = "钱币"; Value = sprintf "%.0f" needs.Money; Icon = MoneyIcon } ]

    // ---- 图标几何与点阵（纯数据/纯函数，Game 与回归测试共用）----

    let iconGrid = 7
    let iconScale = textScale
    let iconWidth = iconGrid * iconScale
    let iconHeight = iconGrid * iconScale
    let iconGap = 6

    /// 7x7 点阵，'1' 为实心。全部原创点阵，仅用现有像素贴图绘制。
    let iconRows (icon: HudIcon) : string list =
        match icon with
        | PeriodIcon ->
            [ "0001000"
              "1010101"
              "0011100"
              "0111110"
              "0011100"
              "1010101"
              "0001000" ]
        | ClockIcon ->
            [ "0011100"
              "0100010"
              "1001001"
              "1001000"
              "1001000"
              "0100010"
              "0011100" ]
        | SpeedIcon ->
            [ "0100010"
              "0110011"
              "0011011"
              "0001110"
              "0011011"
              "0110011"
              "0100010" ]
        | EnergyIcon ->
            [ "0000000"
              "0101010"
              "1111111"
              "1111111"
              "0111110"
              "0011100"
              "0001000" ]
        | MoneyIcon ->
            [ "0011100"
              "0111110"
              "1110111"
              "1100011"
              "1110111"
              "0111110"
              "0011100" ]

    /// 文本起始 x（图标占 iconWidth + iconGap）。
    let textOrigin (segmentX: int) : int = segmentX + iconWidth + iconGap

    /// 段文本（含标签）的像素宽度。
    let segmentWidth (segment: Segment) : int =
        FloatingPrompt.measureWidth (segmentText segment) textScale

    /// 段总宽（图标 + 间隙 + 文本）。
    let segmentSpan (segment: Segment) : int =
        iconWidth + iconGap + segmentWidth segment

    /// 左对齐排布，返回 (起点 x, 总宽, 分段)；段内 x 起为图标，textOrigin 起为文本。
    /// 纯函数，便于布局回归断言。
    let layout (segments: Segment list) : (int * int * Segment) list =
        let _, placed =
            segments
            |> List.fold
                (fun (x, acc) segment ->
                    let width = segmentSpan segment
                    x + width + segmentGap, (x, width, segment) :: acc)
                (paddingX, [])
        List.rev placed

    /// P26：常驻片段文本的 1px 描边偏移（上/下/左/右），保证白天/夜景下都可读。
    let textOutlineOffsets : (int * int) list = [ (-1, 0); (1, 0); (0, -1); (0, 1) ]

    /// P26：常驻片段的半透明底色药丸，贴合文字高度并在左右各留 6px；纯函数便于回归。
    let segmentBackdrop (x: int) (width: int) : Microsoft.Xna.Framework.Rectangle =
        let height = 8 * textScale + 10
        let y = (barHeight - height) / 2
        Microsoft.Xna.Framework.Rectangle(x - 6, y, width + 12, height)

    type Palette =
        { BarTop: Color
          BarBottom: Color
          Accent: Color
          Label: Color
          Value: Color
          SegmentBackdrop: Color
          Outline: Color }

    /// 白天暖色 / 夜晚（冬夜）冷色微调；均为半透明渐变窄条，无大黑块。
    /// 每个常驻片段再叠一层半透明底色 + 1px 深色描边，双时段都能读清。
    let palette (mode: M6DayNight) : Palette =
        match mode with
        | Day ->
            { BarTop = Color(40, 56, 62, 200)
              BarBottom = Color(22, 34, 40, 200)
              Accent = Color(212, 168, 96)
              Label = Color(206, 220, 208)
              Value = Color(242, 248, 234)
              SegmentBackdrop = Color(8, 14, 20, 150)
              Outline = Color(6, 10, 14, 255) }
        | Night ->
            { BarTop = Color(22, 30, 48, 205)
              BarBottom = Color(13, 19, 33, 205)
              Accent = Color(120, 168, 196)
              Label = Color(176, 196, 214)
              Value = Color(228, 238, 246)
              SegmentBackdrop = Color(4, 8, 16, 160)
              Outline = Color(3, 6, 12, 255) }