Charts.ps1

# Charts.ps1 — email-safe plugin visualisations, layered ON TOP of the table/list.
#
# A plugin opts in by setting $Chart (a hashtable) alongside its usual $Display. The engine
# (vCheck.ps1) calls Get-HTMLChart with the raw row objects and prepends the result above the
# rendered table/list, so the chart never replaces the informative detail — it summarises it.
#
# Colours/fonts come from the ACTIVE THEME TOKENS ($cCrit/$cWarn/$cOk/$cAccent/$cSurface/...),
# read from the caller scope exactly like the _common.ps1 renderers — so all 8 themes inherit
# every chart with zero per-theme code.
#
# Donut/Pie are rasterised to a PNG entirely in PowerShell 7 — no System.Drawing (Windows-only),
# no native libraries, no NuGet. Just the BCL (System.IO.Compression for DEFLATE) plus a
# hand-rolled CRC32/Adler32. The PNG is embedded via the existing Add-ReportResource (cid),
# so it renders in every mail client AND the standalone .htm. See CHARTS.md for the contract.

#region ---------------------------------------------------------------- PNG encoder (pure BCL)
$script:CrcTable = New-Object 'uint32[]' 256
$script:CrcPoly = [uint32]0xEDB88320L
for ($n = 0; $n -lt 256; $n++) {
   $c = [uint32]$n
   for ($k = 0; $k -lt 8; $k++) {
      if ($c -band 1) { $c = [uint32]($script:CrcPoly -bxor ([uint32]($c -shr 1))) } else { $c = [uint32]($c -shr 1) }
   }
   $script:CrcTable[$n] = $c
}
function Get-Crc32([byte[]]$bytes) {
   $c = [uint32]0xFFFFFFFFL
   foreach ($b in $bytes) { $c = [uint32]($script:CrcTable[[int](($c -bxor $b) -band 0xFF)] -bxor [uint32]($c -shr 8)) }
   return [uint32]($c -bxor 0xFFFFFFFFL)
}
function Get-Adler32([byte[]]$data) {
   $a = [uint32]1; $b = [uint32]0
   foreach ($byte in $data) { $a = ($a + $byte) % 65521; $b = ($b + $a) % 65521 }
   return [uint32](([uint32]($b -shl 16)) -bor $a)
}
function ConvertTo-BE([uint32]$v) { , ([byte[]]@([byte](($v -shr 24) -band 0xFF), [byte](($v -shr 16) -band 0xFF), [byte](($v -shr 8) -band 0xFF), [byte]($v -band 0xFF))) }
function New-PngChunk([string]$type, [byte[]]$data) {
   $t = [System.Text.Encoding]::ASCII.GetBytes($type)
   return (ConvertTo-BE ([uint32]$data.Length)) + $t + $data + (ConvertTo-BE (Get-Crc32 ($t + $data)))
}
function ConvertTo-Png([byte[]]$rgb, [int]$w, [int]$h) {
   $stride = $w * 3
   $raw = New-Object byte[] ($h * (1 + $stride))
   for ($y = 0; $y -lt $h; $y++) { $raw[$y * (1 + $stride)] = 0; [Array]::Copy($rgb, $y * $stride, $raw, $y * (1 + $stride) + 1, $stride) }
   $ms = New-Object System.IO.MemoryStream
   $ds = New-Object System.IO.Compression.DeflateStream($ms, [System.IO.Compression.CompressionLevel]::Optimal, $true)
   $ds.Write($raw, 0, $raw.Length); $ds.Dispose()
   $zlib = ([byte[]]@(0x78, 0x9C)) + $ms.ToArray() + (ConvertTo-BE (Get-Adler32 $raw))
   $ihdr = (ConvertTo-BE ([uint32]$w)) + (ConvertTo-BE ([uint32]$h)) + ([byte[]]@(8, 2, 0, 0, 0))
   return ([byte[]]@(137, 80, 78, 71, 13, 10, 26, 10)) + (New-PngChunk 'IHDR' $ihdr) + (New-PngChunk 'IDAT' $zlib) + (New-PngChunk 'IEND' (New-Object byte[] 0))
}
#endregion

#region ---------------------------------------------------------------- donut/pie rasteriser
function ConvertFrom-Hex([string]$hex) { $hex = $hex.TrimStart('#'); return @([Convert]::ToInt32($hex.Substring(0, 2), 16), [Convert]::ToInt32($hex.Substring(2, 2), 16), [Convert]::ToInt32($hex.Substring(4, 2), 16)) }
$script:ChartFont = @{
   '0' = @('01110', '10001', '10011', '10101', '11001', '10001', '01110'); '1' = @('00100', '01100', '00100', '00100', '00100', '00100', '01110')
   '2' = @('01110', '10001', '00001', '00010', '00100', '01000', '11111'); '3' = @('11111', '00010', '00100', '00010', '00001', '10001', '01110')
   '4' = @('00010', '00110', '01010', '10010', '11111', '00010', '00010'); '5' = @('11111', '10000', '11110', '00001', '00001', '10001', '01110')
   '6' = @('00110', '01000', '10000', '11110', '10001', '10001', '01110'); '7' = @('11111', '00001', '00010', '00100', '01000', '01000', '01000')
   '8' = @('01110', '10001', '10001', '01110', '10001', '10001', '01110'); '9' = @('01110', '10001', '10001', '01111', '00001', '00010', '01100')
}
# Render at 3x then box-downsample → anti-aliases the ring, segment seams AND the centre text.
function New-DonutPng {
   param([array]$Segments, [int]$Size = 160, [string]$BgHex = '#161B22', [double]$HoleRatio = 0.56, [string]$InkHex = '#E5EDF5', [string]$CenterText = '')
   $F = 3; $big = $Size * $F
   $bg = ConvertFrom-Hex $BgHex; $ink = ConvertFrom-Hex $InkHex
   $segCols = @($Segments | ForEach-Object { , (ConvertFrom-Hex $_.color) })
   $total = ($Segments | Measure-Object -Property value -Sum).Sum; if ($total -le 0) { $total = 1 }
   $cum = @(); $acc = 0.0; foreach ($s in $Segments) { $acc += $s.value / $total; $cum += $acc }
   $cx = $big / 2.0; $cy = $big / 2.0; $outer = $big / 2.0 - ($F * 2); $inner = $outer * $HoleRatio
   $o2 = $outer * $outer; $i2 = $inner * $inner; $twoPi = [math]::PI * 2
   $bigRGB = New-Object byte[] ($big * $big * 3)
   for ($y = 0; $y -lt $big; $y++) {
      for ($x = 0; $x -lt $big; $x++) {
         $fx = $x + 0.5 - $cx; $fy = $y + 0.5 - $cy; $r2 = $fx * $fx + $fy * $fy; $o = ($y * $big + $x) * 3
         if ($r2 -le $o2 -and $r2 -ge $i2) {
            $ang = [math]::Atan2($fx, - $fy); if ($ang -lt 0) { $ang += $twoPi }; $t = $ang / $twoPi
            $idx = 0; for ($g = 0; $g -lt $cum.Count; $g++) { if ($t -le $cum[$g]) { $idx = $g; break } }
            $col = $segCols[$idx]; $bigRGB[$o] = $col[0]; $bigRGB[$o + 1] = $col[1]; $bigRGB[$o + 2] = $col[2]
         }
         else { $bigRGB[$o] = $bg[0]; $bigRGB[$o + 1] = $bg[1]; $bigRGB[$o + 2] = $bg[2] }
      }
   }
   if ($CenterText) {
      $scale = [math]::Max($F, [int]([math]::Floor($inner * 1.15 / 7)))
      $gw = 5 * $scale; $gap = $scale; $txtW = $CenterText.Length * $gw + ($CenterText.Length - 1) * $gap; $txtH = 7 * $scale
      $sX = [int]($cx - $txtW / 2); $sY = [int]($cy - $txtH / 2)
      for ($ci = 0; $ci -lt $CenterText.Length; $ci++) {
         $glyph = $script:ChartFont["$($CenterText[$ci])"]; if (-not $glyph) { continue }
         $gx0 = $sX + $ci * ($gw + $gap)
         for ($ry = 0; $ry -lt 7; $ry++) {
            for ($rx = 0; $rx -lt 5; $rx++) {
               if ($glyph[$ry][$rx] -eq '1') {
                  for ($dy = 0; $dy -lt $scale; $dy++) {
                     for ($dx = 0; $dx -lt $scale; $dx++) {
                        $X = $gx0 + $rx * $scale + $dx; $Y = $sY + $ry * $scale + $dy
                        if ($X -ge 0 -and $X -lt $big -and $Y -ge 0 -and $Y -lt $big) { $o = ($Y * $big + $X) * 3; $bigRGB[$o] = $ink[0]; $bigRGB[$o + 1] = $ink[1]; $bigRGB[$o + 2] = $ink[2] }
                     }
                  }
               }
            }
         }
      }
   }
   $rgb = New-Object byte[] ($Size * $Size * 3); $d = $F * $F
   for ($y = 0; $y -lt $Size; $y++) {
      for ($x = 0; $x -lt $Size; $x++) {
         $ar = 0; $ag = 0; $ab = 0
         for ($dy = 0; $dy -lt $F; $dy++) { for ($dx = 0; $dx -lt $F; $dx++) { $o = ((($y * $F + $dy) * $big) + ($x * $F + $dx)) * 3; $ar += $bigRGB[$o]; $ag += $bigRGB[$o + 1]; $ab += $bigRGB[$o + 2] } }
         $oo = ($y * $Size + $x) * 3; $rgb[$oo] = [byte]($ar / $d); $rgb[$oo + 1] = [byte]($ag / $d); $rgb[$oo + 2] = [byte]($ab / $d)
      }
   }
   return (ConvertTo-Png $rgb $Size $Size)
}
#endregion

#region ---------------------------------------------------------------- colour helpers (theme tokens)
# Map a category label to a severity token by keyword; $null if it isn't a severity word.
function Get-ChartColour([string]$label) {
   $l = ([string]$label).ToLower()
   if ($l -match 'crit|fail|error|non.?compliant|noncompliant|down|unhealthy|expired|disconnect|disabled|insecure|missing|dead|out.?of|incompatible|unavailable|affected|exposed|vulnerable|\bred\b') { return $cCrit }
   if ($l -match 'warn|degrad|aging|old|stale|pending|partial|nearly|approach|\byellow\b') { return $cWarn }
   if ($l -match 'ok|compliant|healthy|pass|connected|enabled|success|online|good|secure|present|mitigated|patched|protected|\bgreen\b') { return $cOk }
   return $null
}
# Threshold colour for a magnitude (higher = worse, unless $Invert).
function Get-ChartThresholdColour([double]$v, $warn, $crit, [bool]$invert) {
   if ($null -eq $warn -and $null -eq $crit) { return $cAccent }
   if ($invert) {
      if ($null -ne $crit -and $v -le $crit) { return $cCrit }
      if ($null -ne $warn -and $v -le $warn) { return $cWarn }
      return $cOk
   }
   if ($null -ne $crit -and $v -ge $crit) { return $cCrit }
   if ($null -ne $warn -and $v -ge $warn) { return $cWarn }
   return $cOk
}
#endregion

#region ---------------------------------------------------------------- HTML chart builders
function Get-ChartDonut($Rows, $Config, [string]$Cid, [bool]$Pie) {
   $grp = [string]$Config.Group
   $segs = @()
   if ($grp) {
      $palette = @($cAccent, $cInfoNum, $cAccentLt); $pi = 0
      foreach ($g in (@($Rows | Group-Object -Property $grp) | Sort-Object Count -Descending)) {
         $col = Get-ChartColour $g.Name; if (-not $col) { $col = $palette[$pi % $palette.Count]; $pi++ }
         $segs += @{ label = [string]$g.Name; value = $g.Count; color = $col }
      }
   }
   elseif ($Config.Segments) { $segs = $Config.Segments }
   if (-not $segs.Count) { return '' }
   $total = ($segs | Measure-Object -Property value -Sum).Sum
   $png = New-DonutPng -Segments $segs -Size 160 -BgHex $cSurface -HoleRatio ($Pie ? 0.0 : 0.56) -InkHex $cInk -CenterText ($Pie ? '' : [string]$total)
   Add-ReportResource -cid $Cid -Type "Base64" -ResourceData ("png|" + [Convert]::ToBase64String($png)) -Used $true
   $leg = ''
   foreach ($s in $segs) { $leg += "<tr><td style='padding:3px 0;'><span style='display:inline-block;width:11px;height:11px;border-radius:3px;background-color:$($s.color);vertical-align:middle;margin-right:9px;'>&nbsp;</span><span style='font-family:$fBody;font-size:12px;color:$cText;'>$($s.label)</span></td><td align='right' style='font-family:$fMono;font-size:12px;font-weight:600;color:$cText;padding:3px 0 3px 20px;'>$($s.value)</td></tr>" }
   return "<div style='margin:0 0 16px 0;'><table role='presentation' cellpadding='0' cellspacing='0' border='0'><tr><td style='vertical-align:middle;padding-right:24px;'><img src='cid:$Cid' width='160' height='160' style='display:block;border:0;' alt='chart' /></td><td style='vertical-align:middle;'><table role='presentation' cellpadding='0' cellspacing='0' border='0'>$leg</table></td></tr></table></div>"
}

function Get-ChartBar($Rows, $Config) {
   $lblP = [string]$Config.Label; $valP = [string]$Config.Value
   $max = $Config.Max; if (-not $max) { $max = 100 }
   $top = $Config.Top; if (-not $top) { $top = 12 }
   $items = @($Rows | Sort-Object -Property $valP -Descending | Select-Object -First $top)
   $rows = ''
   foreach ($it in $items) {
      $v = [double]$it.$valP; $pct = [math]::Min(100, [math]::Round($v / $max * 100)); $rem = 100 - $pct
      $col = Get-ChartThresholdColour $v $Config.Warn $Config.Crit ([bool]$Config.Invert)
      $rows += "<tr><td width='170' style='font-family:$fBody;font-size:12px;color:$cText;padding:4px 10px 4px 0;white-space:nowrap;'>$($it.$lblP)</td><td style='padding:4px 0;'><table role='presentation' width='100%' cellpadding='0' cellspacing='0' border='0' bgcolor='$cSurfaceAlt' style='background-color:$cSurfaceAlt;border-radius:4px;'><tr><td width='$pct%' bgcolor='$col' style='background-color:$col;height:14px;line-height:14px;font-size:0;border-radius:4px;'>&nbsp;</td><td width='$rem%' style='font-size:0;line-height:14px;'>&nbsp;</td></tr></table></td><td width='58' align='right' style='font-family:$fMono;font-size:12px;font-weight:600;color:$col;padding:4px 0 4px 10px;font-variant-numeric:tabular-nums;'>$($it.$valP)</td></tr>"
   }
   return "<div style='margin:0 0 16px 0;'><table role='presentation' width='100%' cellpadding='0' cellspacing='0' border='0'>$rows</table></div>"
}

function Get-ChartStacked($Rows, $Config) {
   $c = 0; $w = 0; $o = 0
   if ($Config.Group) {
      foreach ($r in $Rows) { $col = Get-ChartColour $r.($Config.Group); if ($col -eq $cCrit) { $c++ } elseif ($col -eq $cWarn) { $w++ } else { $o++ } }
   }
   else { $c = [int]$Config.Critical; $w = [int]$Config.Warning; $o = [int]$Config.OK }
   $t = $c + $w + $o; if ($t -eq 0) { $t = 1 }
   $cp = [math]::Round($c / $t * 100); $wp = [math]::Round($w / $t * 100); $op = 100 - $cp - $wp
   $seg = ''
   if ($cp) { $seg += "<td width='$cp%' bgcolor='$cCrit' style='background-color:$cCrit;height:22px;line-height:22px;font-size:0;'>&nbsp;</td>" }
   if ($wp) { $seg += "<td width='$wp%' bgcolor='$cWarn' style='background-color:$cWarn;height:22px;line-height:22px;font-size:0;'>&nbsp;</td>" }
   if ($op) { $seg += "<td width='$op%' bgcolor='$cOk' style='background-color:$cOk;height:22px;line-height:22px;font-size:0;'>&nbsp;</td>" }
   $legend = "<table role='presentation' cellpadding='0' cellspacing='0' border='0' style='margin-top:10px;'><tr>" +
   "<td style='padding-right:18px;font-family:$fBody;font-size:11px;color:$cTextMuted;'><span style='display:inline-block;width:9px;height:9px;background-color:$cCrit;border-radius:2px;margin-right:6px;'>&nbsp;</span>Critical $c</td>" +
   "<td style='padding-right:18px;font-family:$fBody;font-size:11px;color:$cTextMuted;'><span style='display:inline-block;width:9px;height:9px;background-color:$cWarn;border-radius:2px;margin-right:6px;'>&nbsp;</span>Warning $w</td>" +
   "<td style='font-family:$fBody;font-size:11px;color:$cTextMuted;'><span style='display:inline-block;width:9px;height:9px;background-color:$cOk;border-radius:2px;margin-right:6px;'>&nbsp;</span>OK $o</td></tr></table>"
   return "<div style='margin:0 0 16px 0;'><table role='presentation' width='100%' cellpadding='0' cellspacing='0' border='0' style='border-radius:5px;overflow:hidden;'><tr>$seg</tr></table>$legend</div>"
}

function Get-ChartGauge($Rows, $Config) {
   $lblP = [string]$Config.Label; $valP = [string]$Config.Value
   $max = $Config.Max; if (-not $max) { $max = 100 }
   $blocks = ''
   foreach ($r in @($Rows)) {
      $v = [double]$r.$valP; $pct = [math]::Min(100, [math]::Round($v / $max * 100)); $rem = 100 - $pct
      $col = Get-ChartThresholdColour $v $Config.Warn $Config.Crit ([bool]$Config.Invert)
      $blocks += "<div style='font-family:$fDisplay;font-size:13px;font-weight:600;letter-spacing:1.5px;text-transform:uppercase;color:$cInk;padding:0 0 7px 0;'>$($r.$lblP) <span style='font-family:$fMono;color:$col;float:right;'>$($r.$valP)</span></div><table role='presentation' width='100%' cellpadding='0' cellspacing='0' border='0' bgcolor='$cSurfaceAlt' style='background-color:$cSurfaceAlt;border-radius:5px;border:1px solid $cBorder;margin-bottom:14px;'><tr><td width='$pct%' bgcolor='$col' style='background-color:$col;height:18px;line-height:18px;font-size:0;border-radius:4px;'>&nbsp;</td><td width='$rem%' style='font-size:0;line-height:18px;'>&nbsp;</td></tr></table>"
   }
   return "<div style='margin:0 0 4px 0;'>$blocks</div>"
}

function Get-ChartHeat($Rows, $Config) {
   $stP = [string]$Config.Status; $perRow = $Config.PerRow; if (-not $perRow) { $perRow = 24 }
   $cells = ''; $n = 0
   foreach ($r in @($Rows)) {
      $col = $stP ? (Get-ChartColour $r.$stP) : $null; if (-not $col) { $col = $cOk }
      $cells += "<td style='padding:2px;'><div style='width:18px;height:18px;background-color:$col;border-radius:3px;'>&nbsp;</div></td>"
      $n++; if ($n % $perRow -eq 0) { $cells += "</tr><tr>" }
   }
   return "<div style='margin:0 0 16px 0;'><table role='presentation' cellpadding='0' cellspacing='0' border='0'><tr>$cells</tr></table></div>"
}

function Get-ChartSparkline($Rows, $Config) {
   $valP = [string]$Config.Value
   $vals = @($Rows | ForEach-Object { [double]$_.$valP })
   $maxV = ($vals | Measure-Object -Maximum).Maximum; if ($maxV -le 0) { $maxV = 1 }
   $tds = ''
   foreach ($v in $vals) { $h = [math]::Max(3, [math]::Round($v / $maxV * 44)); $tds += "<td valign='bottom' style='padding:0 2px;'><table role='presentation' cellpadding='0' cellspacing='0' border='0'><tr><td width='10' bgcolor='$cAccent' style='background-color:$cAccent;height:${h}px;line-height:${h}px;font-size:0;border-radius:2px 2px 0 0;'>&nbsp;</td></tr></table></td>" }
   return "<div style='margin:0 0 16px 0;'><table role='presentation' cellpadding='0' cellspacing='0' border='0' style='height:48px;'><tr valign='bottom'>$tds</tr></table></div>"
}
#endregion

# Dispatcher — called by the engine. $Cid must be unique per chart (for the PNG resource).
function Get-HTMLChart {
   param($Rows, $Config, [string]$Cid)
   if (-not $Rows -or -not $Config) { return '' }
   try {
      switch -Regex ([string]$Config.Type) {
         '^(Donut|Pie)$' { return (Get-ChartDonut $Rows $Config $Cid ([string]$Config.Type -eq 'Pie')) }
         '^Bar$' { return (Get-ChartBar $Rows $Config) }
         '^Stacked$' { return (Get-ChartStacked $Rows $Config) }
         '^Gauge$' { return (Get-ChartGauge $Rows $Config) }
         '^Heat$' { return (Get-ChartHeat $Rows $Config) }
         '^Spark(line)?$' { return (Get-ChartSparkline $Rows $Config) }
         default { return '' }
      }
   }
   catch { Write-Warning ("Chart '{0}' failed: {1}" -f $Config.Type, $_.Exception.Message); return '' }
}