# 从 Assets/gotify-mascot.png 生成多分辨率 ICO
# 输出:Assets/gotify-mascot.ico
param(
    [string]$Png = "$PSScriptRoot\gotify-mascot.png",
    [string]$Ico = "$PSScriptRoot\gotify-mascot.ico"
)

Add-Type -AssemblyName System.Drawing

$src = [System.Drawing.Image]::FromFile((Resolve-Path $Png))
$srcW = $src.Width
$srcH = $src.Height

# 多分辨率列表(像素) — 包含原始尺寸
$sizes = @(16, 24, 32, 48, 64, 128, 196) | Where-Object { $_ -le [math]::Max($srcW, $srcH) }
if (($srcW, $srcH) -notin $sizes) { $sizes += ,($srcW, $srcH) | Out-Null }
$sizes = $sizes | Sort-Object -Unique

# 1) 把每个分辨率的位图渲染成 PNG 字节
$entries = @()
foreach ($sz in $sizes) {
    $bmp = New-Object System.Drawing.Bitmap $sz, $sz, ([System.Drawing.Imaging.PixelFormat]::Format32bppArgb)
    $g = [System.Drawing.Graphics]::FromImage($bmp)
    $g.InterpolationMode = [System.Drawing.Drawing2D.InterpolationMode]::HighQualityBicubic
    $g.SmoothingMode = [System.Drawing.Drawing2D.SmoothingMode]::HighQuality
    $g.PixelOffsetMode = [System.Drawing.Drawing2D.PixelOffsetMode]::HighQuality
    $g.Clear([System.Drawing.Color]::Transparent)
    $g.DrawImage($src, 0, 0, $sz, $sz)
    $g.Dispose()

    $ms = New-Object System.IO.MemoryStream
    $bmp.Save($ms, [System.Drawing.Imaging.ImageFormat]::Png)
    $pngBytes = $ms.ToArray()
    $ms.Dispose()
    $bmp.Dispose()

    $entries += [pscustomobject]@{
        Width = $sz
        Height = $sz
        Bytes = $pngBytes
    }
}
$src.Dispose()

# 2) 组装 ICO 文件
#   ICONDIR (6 bytes)
#   ICONDIRENTRY * N (16 bytes each)
#   Image data

$out = New-Object System.IO.MemoryStream
$bw = New-Object System.IO.BinaryWriter $out

# ICONDIR
$bw.Write([uint16]0)        # Reserved
$bw.Write([uint16]1)        # Type: 1 = ICO
$bw.Write([uint16]$entries.Count)  # Count

# ICONDIRENTRY (16 bytes each)
$dataOffset = 6 + 16 * $entries.Count
foreach ($e in $entries) {
    $w = if ($e.Width  -ge 256) { 0 } else { $e.Width  }
    $h = if ($e.Height -ge 256) { 0 } else { $e.Height }
    $bw.Write([byte]$w)             # Width
    $bw.Write([byte]$h)             # Height
    $bw.Write([byte]0)              # Color count (0 = >256 colors)
    $bw.Write([byte]0)              # Reserved
    $bw.Write([uint16]1)            # Color planes
    $bw.Write([uint16]32)           # Bits per pixel
    $bw.Write([uint32]$e.Bytes.Length)
    $bw.Write([uint32]$dataOffset)
    $dataOffset += $e.Bytes.Length
}

# Image data
foreach ($e in $entries) {
    $bw.Write($e.Bytes)
}

$bw.Flush()
[System.IO.File]::WriteAllBytes($Ico, $out.ToArray())
$bw.Dispose()
$out.Dispose()

Write-Host "ICO built: $Ico ($((Get-Item $Ico).Length) bytes, $($entries.Count) sizes: $($sizes -join ','))"