[CmdletBinding()]
param(
  [string] $Root = (Split-Path -Parent $PSScriptRoot)
)

$ErrorActionPreference = 'Stop'
Add-Type -AssemblyName System.Drawing

$sourcePath = Join-Path $Root 'assets\icons\app_icon.png'
if (-not (Test-Path -LiteralPath $sourcePath -PathType Leaf)) {
  throw "App icon source was not found: $sourcePath"
}

function New-ResizedBitmap {
  param(
    [Drawing.Image] $Source,
    [int] $Width,
    [int] $Height,
    [int] $Padding = 0,
    [Drawing.Color] $Background = [Drawing.Color]::Transparent,
    [switch] $SharpenSmallAlpha
  )

  $bitmap = [Drawing.Bitmap]::new($Width, $Height, [Drawing.Imaging.PixelFormat]::Format32bppArgb)
  $graphics = [Drawing.Graphics]::FromImage($bitmap)
  try {
    $graphics.CompositingMode = [Drawing.Drawing2D.CompositingMode]::SourceCopy
    $graphics.CompositingQuality = [Drawing.Drawing2D.CompositingQuality]::HighQuality
    $graphics.InterpolationMode = [Drawing.Drawing2D.InterpolationMode]::HighQualityBicubic
    $graphics.PixelOffsetMode = [Drawing.Drawing2D.PixelOffsetMode]::HighQuality
    $graphics.SmoothingMode = [Drawing.Drawing2D.SmoothingMode]::HighQuality
    $graphics.Clear($Background)

    $availableWidth = $Width - (2 * $Padding)
    $availableHeight = $Height - (2 * $Padding)
    $scale = [Math]::Min($availableWidth / $Source.Width, $availableHeight / $Source.Height)
    $drawWidth = [Math]::Max(1, [int][Math]::Round($Source.Width * $scale))
    $drawHeight = [Math]::Max(1, [int][Math]::Round($Source.Height * $scale))
    $drawX = [int][Math]::Floor(($Width - $drawWidth) / 2)
    $drawY = [int][Math]::Floor(($Height - $drawHeight) / 2)
    $attributes = [Drawing.Imaging.ImageAttributes]::new()
    try {
      $attributes.SetWrapMode([Drawing.Drawing2D.WrapMode]::TileFlipXY)
      $graphics.DrawImage(
        $Source,
        [Drawing.Rectangle]::new($drawX, $drawY, $drawWidth, $drawHeight),
        0,
        0,
        $Source.Width,
        $Source.Height,
        [Drawing.GraphicsUnit]::Pixel,
        $attributes)
    } finally {
      $attributes.Dispose()
    }
  } finally {
    $graphics.Dispose()
  }

  if ($SharpenSmallAlpha) {
    for ($y = 0; $y -lt $Height; $y++) {
      for ($x = 0; $x -lt $Width; $x++) {
        $color = $bitmap.GetPixel($x, $y)
        if ($color.A -le 10) {
          $bitmap.SetPixel($x, $y, [Drawing.Color]::Transparent)
        } else {
          $alpha = if ($color.A -ge 244) { 255 } else { [Math]::Min(255, [int](($color.A - 10) * 255 / 234)) }
          $bitmap.SetPixel($x, $y, [Drawing.Color]::FromArgb($alpha, 0, 114, 255))
        }
      }
    }
  }

  return $bitmap
}

function Get-PngBytes([Drawing.Bitmap] $Bitmap) {
  $stream = [IO.MemoryStream]::new()
  try {
    $Bitmap.Save($stream, [Drawing.Imaging.ImageFormat]::Png)
    return $stream.ToArray()
  } finally {
    $stream.Dispose()
  }
}

function Write-PngIconFile([string] $Path, [hashtable] $Frames) {
  $orderedSizes = @($Frames.Keys | ForEach-Object { [int] $_ } | Sort-Object)
  $headerSize = 6 + (16 * $orderedSizes.Count)
  $offset = $headerSize
  $stream = [IO.MemoryStream]::new()
  $writer = [IO.BinaryWriter]::new($stream)
  try {
    $writer.Write([uint16] 0)
    $writer.Write([uint16] 1)
    $writer.Write([uint16] $orderedSizes.Count)
    foreach ($size in $orderedSizes) {
      $bytes = [byte[]] $Frames[$size]
      $writer.Write([byte] $(if ($size -eq 256) { 0 } else { $size }))
      $writer.Write([byte] $(if ($size -eq 256) { 0 } else { $size }))
      $writer.Write([byte] 0)
      $writer.Write([byte] 0)
      $writer.Write([uint16] 1)
      $writer.Write([uint16] 32)
      $writer.Write([uint32] $bytes.Length)
      $writer.Write([uint32] $offset)
      $offset += $bytes.Length
    }
    foreach ($size in $orderedSizes) {
      $writer.Write([byte[]] $Frames[$size])
    }
    $writer.Flush()
    $directory = Split-Path -Parent $Path
    if ($directory) { [IO.Directory]::CreateDirectory($directory) | Out-Null }
    [IO.File]::WriteAllBytes($Path, $stream.ToArray())
  } finally {
    $writer.Dispose()
    $stream.Dispose()
  }
}

function Save-Logo {
  param(
    [Drawing.Image] $Source,
    [string] $Path,
    [int] $Width,
    [int] $Height,
    [int] $Padding,
    [Drawing.Color] $Background = [Drawing.Color]::Transparent
  )
  $bitmap = New-ResizedBitmap $Source $Width $Height $Padding $Background
  try {
    [IO.Directory]::CreateDirectory((Split-Path -Parent $Path)) | Out-Null
    $bitmap.Save($Path, [Drawing.Imaging.ImageFormat]::Png)
  } finally {
    $bitmap.Dispose()
  }
}

$loaded = [Drawing.Bitmap]::FromFile($sourcePath)
try {
  $master = [Drawing.Bitmap]::new($loaded)
} finally {
  $loaded.Dispose()
}

try {
  $frames = @{}
  foreach ($size in @(16, 20, 24, 32, 40, 48, 64, 96, 128, 256)) {
    $frame = New-ResizedBitmap $master $size $size 0 ([Drawing.Color]::Transparent) -SharpenSmallAlpha:($size -le 24)
    try {
      $frames[$size] = Get-PngBytes $frame
    } finally {
      $frame.Dispose()
    }
  }

  $iconTargets = @(
    (Join-Path $Root 'assets\icon.ico'),
    (Join-Path $Root 'assets\icons\app_icon.ico'),
    (Join-Path $Root 'src\box-winUI\Assets\app_icon.ico'),
    (Join-Path $Root 'src\YMhut.Box.PluginTauriHost\src-tauri\icons\icon.ico')
  )
  foreach ($target in $iconTargets) {
    Write-PngIconFile $target $frames
  }

  $normalizedSource = Join-Path ([IO.Path]::GetTempPath()) ("ymhut-app-icon-{0}.png" -f [Guid]::NewGuid().ToString('N'))
  try {
    $master.Save($normalizedSource, [Drawing.Imaging.ImageFormat]::Png)
    Copy-Item -LiteralPath $normalizedSource -Destination (Join-Path $Root 'assets\icons\app_icon.png') -Force
    Copy-Item -LiteralPath $normalizedSource -Destination (Join-Path $Root 'assets\icons\icon.png') -Force
  } finally {
    Remove-Item -LiteralPath $normalizedSource -Force -ErrorAction SilentlyContinue
  }

  $projectAssets = Join-Path $Root 'src\box-winUI\Assets'
  Save-Logo $master (Join-Path $projectAssets 'StoreLogo.png') 50 50 5
  Save-Logo $master (Join-Path $projectAssets 'Square44x44Logo.png') 44 44 4
  Save-Logo $master (Join-Path $projectAssets 'Square150x150Logo.png') 150 150 16
  Save-Logo $master (Join-Path $projectAssets 'LockScreenLogo.png') 70 70 8
  Save-Logo $master (Join-Path $projectAssets 'Wide310x150Logo.png') 310 150 24 ([Drawing.Color]::FromArgb(255, 245, 246, 247))
} finally {
  $master.Dispose()
}

Write-Host 'Generated DPI-aware YMhut Box application icons.'