param()

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing

# =====================================================================
# USER SETTINGS - change these values yourself
# =====================================================================
# CPU load threshold (%) that triggers 100% fans when CPU Auto is ON.
$script:CpuAutoEnterThresholdDefault = 80

# CPU load threshold (%) that allows the release countdown to start.
# Once this value is reached, the hold countdown starts and keeps running.
# The countdown is cancelled only if CPU load rises back to the ENTER threshold.
$script:CpuAutoExitThresholdDefault = 5

# Default hold time, in seconds, used when the app starts.
$script:CpuAutoReleaseHoldDefault = 17

# Dropdown options for hold time, in seconds.
$script:CpuAutoReleaseHoldOptions = @(0, 5, 10, 13, 15, 17, 20, 25, 30, 35, 45, 60)

# Dropdown options for CPU auto ENTER threshold (%).
$script:CpuAutoEnterThresholdOptions = @(10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100)
$script:CpuAutoExitThresholdOptions = @(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20)

# Known practical maximum fan RPM used only for percentage displays.
$script:KnownMaxFanRpm = 4830
# =====================================================================

# =====================================================================
# THEME
# =====================================================================
$script:ColorAppBg        = [System.Drawing.Color]::FromArgb(18, 18, 20)
$script:ColorCardBg       = [System.Drawing.Color]::FromArgb(28, 30, 34)
$script:ColorCardBorder   = [System.Drawing.Color]::FromArgb(52, 56, 62)
$script:ColorTextPrimary  = [System.Drawing.Color]::FromArgb(240, 243, 247)
$script:ColorTextMuted    = [System.Drawing.Color]::FromArgb(160, 166, 175)
$script:ColorAccent       = [System.Drawing.Color]::FromArgb(91, 157, 255)
$script:ColorSuccess      = [System.Drawing.Color]::FromArgb(66, 184, 131)
$script:ColorWarning      = [System.Drawing.Color]::FromArgb(255, 179, 71)
$script:ColorDanger       = [System.Drawing.Color]::FromArgb(224, 87, 87)
$script:ColorButtonDark   = [System.Drawing.Color]::FromArgb(42, 45, 51)
$script:ColorButtonHover  = [System.Drawing.Color]::FromArgb(60, 64, 72)
$script:ColorInputBg      = [System.Drawing.Color]::FromArgb(34, 36, 40)

$script:FontUi        = New-Object System.Drawing.Font('Segoe UI', 9.75, [System.Drawing.FontStyle]::Regular)
$script:FontUiBold    = New-Object System.Drawing.Font('Segoe UI Semibold', 9.75, [System.Drawing.FontStyle]::Bold)
$script:FontTitle     = New-Object System.Drawing.Font('Segoe UI Semibold', 13.0, [System.Drawing.FontStyle]::Bold)
$script:FontCardTitle = New-Object System.Drawing.Font('Segoe UI Semibold', 10.5, [System.Drawing.FontStyle]::Bold)
$script:FontValue     = New-Object System.Drawing.Font('Segoe UI Semibold', 10.5, [System.Drawing.FontStyle]::Bold)
# =====================================================================

function Test-IsAdmin {
    $id = [Security.Principal.WindowsIdentity]::GetCurrent()
    $p = New-Object Security.Principal.WindowsPrincipal($id)
    return $p.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
}

function Restart-Elevated {
    $psi = New-Object System.Diagnostics.ProcessStartInfo
    $psi.FileName = 'powershell.exe'
    $psi.Arguments = "-NoProfile -ExecutionPolicy Bypass -WindowStyle Hidden -File `"$PSCommandPath`""
    $psi.Verb = 'runas'
    $psi.UseShellExecute = $true
    [void][System.Diagnostics.Process]::Start($psi)
}

if (-not (Test-IsAdmin)) {
    try {
        Restart-Elevated
    } catch {
        [System.Windows.Forms.MessageBox]::Show(
            "Script must run as administrator.`r`n`r`n$($_.Exception.Message)",
            'Dell G15 Fan Control',
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Error
        ) | Out-Null
    }
    exit
}

$script:AppName = 'Dell G15 Fan Control Author: Lilita Bogachkova'
$script:CpuFanId = 51
$script:GpuFanId = 50
$script:AwccObject = $null
$script:ObservedPeakCpuRpm = 0
$script:ObservedPeakGpuRpm = 0
$script:LastCommand = 'Application started'
$script:LastRefreshTime = [datetime]::MinValue
$script:IsBusy = $false
$script:CpuCounter = $null
$script:CpuCounterName = 'Not initialized'

# CPU auto is ON by default.
$script:CpuAutoEnabled = $true
$script:CpuAutoLatched = $false
$script:CpuAutoEnterThreshold = [double]$script:CpuAutoEnterThresholdDefault
$script:CpuAutoExitThreshold = [double]$script:CpuAutoExitThresholdDefault
$script:CpuAutoReleaseHoldSeconds = [int]$script:CpuAutoReleaseHoldDefault
$script:CpuAutoReleasePendingUntil = [datetime]::MinValue

# Manual force state. CPU auto has higher priority whenever its logic becomes active.
$script:ManualForceEnabled = $false

function Set-DoubleBuffered {
    param([System.Windows.Forms.Control]$Control)
    try {
        $prop = $Control.GetType().GetProperty('DoubleBuffered', [System.Reflection.BindingFlags]'NonPublic,Instance')
        if ($null -ne $prop) {
            $prop.SetValue($Control, $true, $null)
        }
    } catch {}
}

function New-CardPanel {
    param(
        [string]$Title,
        [int]$X,
        [int]$Y,
        [int]$Width,
        [int]$Height
    )

    $panel = New-Object System.Windows.Forms.Panel
    $panel.Location = New-Object System.Drawing.Point($X, $Y)
    $panel.Size = New-Object System.Drawing.Size($Width, $Height)
    $panel.BackColor = $script:ColorCardBg
    $panel.BorderStyle = 'FixedSingle'
    Set-DoubleBuffered -Control $panel

    $titleLabel = New-Object System.Windows.Forms.Label
    $titleLabel.Text = $Title
    $titleLabel.Location = New-Object System.Drawing.Point(16, 12)
    $titleLabel.Size = New-Object System.Drawing.Size(($Width - 32), 24)
    $titleLabel.Font = $script:FontCardTitle
    $titleLabel.ForeColor = $script:ColorTextPrimary
    $titleLabel.BackColor = $script:ColorCardBg

    $separator = New-Object System.Windows.Forms.Panel
    $separator.Location = New-Object System.Drawing.Point(16, 40)
    $separator.Size = New-Object System.Drawing.Size(($Width - 32), 1)
    $separator.BackColor = $script:ColorCardBorder

    $panel.Controls.AddRange(@($titleLabel, $separator))
    return $panel
}

function New-InfoLabel {
    param([string]$Text, [int]$X, [int]$Y, [int]$Width)
    $lbl = New-Object System.Windows.Forms.Label
    $lbl.Text = $Text
    $lbl.Location = New-Object System.Drawing.Point($X, $Y)
    $lbl.Size = New-Object System.Drawing.Size($Width, 22)
    $lbl.Font = $script:FontUi
    $lbl.ForeColor = $script:ColorTextMuted
    $lbl.BackColor = [System.Drawing.Color]::Transparent
    return $lbl
}

function New-ValueLabel {
    param([string]$Text, [int]$X, [int]$Y, [int]$Width)
    $lbl = New-Object System.Windows.Forms.Label
    $lbl.Text = $Text
    $lbl.Location = New-Object System.Drawing.Point($X, $Y)
    $lbl.Size = New-Object System.Drawing.Size($Width, 22)
    $lbl.Font = $script:FontValue
    $lbl.ForeColor = $script:ColorTextPrimary
    $lbl.BackColor = [System.Drawing.Color]::Transparent
    return $lbl
}

function New-ModernButton {
    param(
        [string]$Text,
        [int]$X,
        [int]$Y,
        [int]$Width,
        [int]$Height,
        [System.Drawing.Color]$BackColor,
        [System.Drawing.Color]$ForeColor
    )

    $btn = New-Object System.Windows.Forms.Button
    $btn.Text = $Text
    $btn.Location = New-Object System.Drawing.Point($X, $Y)
    $btn.Size = New-Object System.Drawing.Size($Width, $Height)
    $btn.Font = $script:FontUiBold
    $btn.FlatStyle = 'Flat'
    $btn.FlatAppearance.BorderSize = 0
    $btn.FlatAppearance.MouseOverBackColor = $script:ColorButtonHover
    $btn.FlatAppearance.MouseDownBackColor = $script:ColorButtonHover
    $btn.BackColor = $BackColor
    $btn.ForeColor = $ForeColor
    $btn.TabStop = $false
    return $btn
}

function New-ReadoutBox {
    param([string]$Text, [int]$X, [int]$Y, [int]$Width)
    $lbl = New-Object System.Windows.Forms.Label
    $lbl.Text = $Text
    $lbl.Location = New-Object System.Drawing.Point($X, $Y)
    $lbl.Size = New-Object System.Drawing.Size($Width, 24)
    $lbl.Font = $script:FontUiBold
    $lbl.ForeColor = $script:ColorTextPrimary
    $lbl.BackColor = $script:ColorInputBg
    $lbl.BorderStyle = 'FixedSingle'
    $lbl.TextAlign = 'MiddleCenter'
    return $lbl
}

function Set-LabelText {
    param([System.Windows.Forms.Label]$Label, [string]$Text)
    if ($Label.Text -ne $Text) {
        $Label.Text = $Text
    }
}

function Initialize-AutoUiState {
    $script:CpuAutoEnabled = $true
    $script:CpuAutoLatched = $false
    $script:ManualForceEnabled = $false
    Clear-PendingRelease
    Update-AutoButtonText
    Update-StateBadge -StateText (Get-AutoStateText)
}

function Test-IsPendingRelease {
    return ($script:CpuAutoReleasePendingUntil -gt [datetime]::MinValue)
}

function Clear-PendingRelease {
    $script:CpuAutoReleasePendingUntil = [datetime]::MinValue
}

function Get-AwccObject {
    if ($null -ne $script:AwccObject) {
        return $script:AwccObject
    }

    $obj = Get-WmiObject -Namespace 'root\WMI' -Class 'AWCCWmiMethodFunction' | Select-Object -First 1
    if ($null -eq $obj) {
        throw "AWCCWmiMethodFunction object was not found in root\\WMI."
    }

    $script:AwccObject = $obj
    return $script:AwccObject
}

function Invoke-AwccMethod {
    param(
        [Parameter(Mandatory)][string]$MethodName,
        [Parameter(Mandatory)][uint32]$Arg2
    )

    $obj = Get-AwccObject

    if (-not ($obj | Get-Member -Name $MethodName -MemberType Method)) {
        throw "AWCC method '$MethodName' is not available."
    }

    $result = $obj.$MethodName($Arg2)

    if ($null -eq $result) {
        throw "AWCC method '$MethodName' returned null."
    }

    if ($result -is [array]) {
        if ($result.Count -lt 1) {
            throw "AWCC method '$MethodName' returned an empty array."
        }
        return [uint32]$result[0]
    }

    if ($result.PSObject.Properties.Match('argr').Count -gt 0) {
        return [uint32]$result.argr
    }

    return [uint32]$result
}

function Set-ThermalModeByCode {
    param([Parameter(Mandatory)][int]$ModeCode)

    $arg = (([uint32]($ModeCode -band 0xFF)) -shl 8) -bor 1
    $result = Invoke-AwccMethod -MethodName 'Thermal_Control' -Arg2 ([uint32]$arg)
    return ($result -eq 0)
}

function Set-BalancedMode {
    if (Set-ThermalModeByCode -ModeCode 160) { return $true }
    return (Set-ThermalModeByCode -ModeCode 151)
}

function Set-FullSpeedMode {
    return (Set-ThermalModeByCode -ModeCode 153)
}

function Set-CustomMode {
    return (Set-ThermalModeByCode -ModeCode 0)
}

function Set-FanPercent {
    param(
        [Parameter(Mandatory)][int]$FanId,
        [Parameter(Mandatory)][int]$Percent
    )

    $p = [Math]::Max(0, [Math]::Min(100, $Percent))
    $arg = (([uint32]($p -band 0xFF)) -shl 16) -bor (([uint32]($FanId -band 0xFF)) -shl 8) -bor 2
    $result = Invoke-AwccMethod -MethodName 'Thermal_Control' -Arg2 ([uint32]$arg)
    return ($result -eq 0)
}

function Get-FanRpm {
    param([Parameter(Mandatory)][int]$FanId)

    $arg = (([uint32]($FanId -band 0xFF)) -shl 8) -bor 5
    $raw = Invoke-AwccMethod -MethodName 'Thermal_Information' -Arg2 ([uint32]$arg)

    if ($raw -eq 0xFFFFFFFF) { return $null }
    if ($raw -gt 20000) { return $null }
    return [int]$raw
}

function Initialize-CpuCounter {
    if ($null -ne $script:CpuCounter) {
        return
    }

    try {
        $script:CpuCounter = New-Object System.Diagnostics.PerformanceCounter('Processor Information', '% Processor Utility', '_Total', $true)
        $script:CpuCounterName = 'Processor Information / % Processor Utility'
    } catch {
        $script:CpuCounter = New-Object System.Diagnostics.PerformanceCounter('Processor', '% Processor Time', '_Total', $true)
        $script:CpuCounterName = 'Processor / % Processor Time'
    }

    try {
        $null = $script:CpuCounter.NextValue()
    } catch {}
}

function Get-CpuLoadValue {
    Initialize-CpuCounter

    try {
        $value = [double]$script:CpuCounter.NextValue()
    } catch {
        return 0.0
    }

    if ($value -lt 0) { $value = 0 }
    if ($value -gt 100) { $value = 100 }

    return [Math]::Round($value, 1)
}

function Update-Peaks {
    param($CpuRpm, $GpuRpm)

    if ($null -ne $CpuRpm -and [int]$CpuRpm -gt $script:ObservedPeakCpuRpm) {
        $script:ObservedPeakCpuRpm = [int]$CpuRpm
    }

    if ($null -ne $GpuRpm -and [int]$GpuRpm -gt $script:ObservedPeakGpuRpm) {
        $script:ObservedPeakGpuRpm = [int]$GpuRpm
    }
}

function Get-PercentOfReference {
    param($Current, [int]$Reference)

    if ($Reference -le 0 -or $null -eq $Current) {
        return '-'
    }

    $pct = [Math]::Round(([double]$Current / [double]$Reference) * 100.0, 1)
    return ('{0:N1} %' -f $pct)
}

function Format-RpmVsKnownMax {
    param($RpmValue)

    if ($null -eq $RpmValue -or [int]$script:KnownMaxFanRpm -le 0) {
        return '-'
    }

    $pct = [Math]::Round(([double]$RpmValue / [double]$script:KnownMaxFanRpm) * 100.0, 1)
    return ('{0} / {1} ({2:N1} %)' -f [int]$RpmValue, [int]$script:KnownMaxFanRpm, $pct)
}

function Update-AutoButtonText {
    if ($script:ManualForceEnabled) {
        $btnForce100.Text = 'Force 100%: ON'
        $btnForce100.BackColor = $script:ColorDanger
        $btnReleaseAuto.Text = 'Return to Auto: OFF'
        $btnReleaseAuto.BackColor = $script:ColorButtonDark
        $btnCpuAuto.Text = 'CPU Load Auto: OFF'
        $btnCpuAuto.BackColor = $script:ColorButtonDark
        return
    }

    if ($script:CpuAutoEnabled) {
        $btnForce100.Text = 'Force 100%: OFF'
        $btnForce100.BackColor = $script:ColorButtonDark
        $btnReleaseAuto.Text = 'Return to Auto: OFF'
        $btnReleaseAuto.BackColor = $script:ColorButtonDark
        $btnCpuAuto.Text = 'CPU Load Auto: ON'
        $btnCpuAuto.BackColor = $script:ColorAccent
        return
    }

    $btnForce100.Text = 'Force 100%: OFF'
    $btnForce100.BackColor = $script:ColorButtonDark
    $btnReleaseAuto.Text = 'Return to Auto: ON'
    $btnReleaseAuto.BackColor = $script:ColorSuccess
    $btnCpuAuto.Text = 'CPU Load Auto: OFF'
    $btnCpuAuto.BackColor = $script:ColorButtonDark
}

function Update-StateBadge {
    param([string]$StateText)

    Set-LabelText -Label $lblAutoStateValue -Text $StateText

    if ($StateText -like 'Hold *' -or $StateText -like 'Latched*' -or $StateText -like '*manual 100%') {
        $lblAutoStateValue.ForeColor = $script:ColorWarning
    } elseif ($StateText -eq 'Armed' -or $StateText -eq 'Dell Auto') {
        $lblAutoStateValue.ForeColor = $script:ColorSuccess
    } elseif ($StateText -eq 'Disabled') {
        $lblAutoStateValue.ForeColor = $script:ColorTextMuted
    } else {
        $lblAutoStateValue.ForeColor = $script:ColorTextPrimary
    }
}

function Update-StatusBar {
    param([string]$Text)

    Set-LabelText -Label $lblStatus -Text $Text

    if ($Text -like '*error*' -or $Text -like '*failed*') {
        $statusPanel.BackColor = [System.Drawing.Color]::FromArgb(64, 29, 29)
        $lblStatus.ForeColor = $script:ColorDanger
    } elseif ($Text -like '*100%*' -or $Text -like '*latched*' -or $Text -like '*Holding*') {
        $statusPanel.BackColor = [System.Drawing.Color]::FromArgb(55, 45, 28)
        $lblStatus.ForeColor = $script:ColorWarning
    } else {
        $statusPanel.BackColor = [System.Drawing.Color]::FromArgb(26, 28, 32)
        $lblStatus.ForeColor = $script:ColorTextPrimary
    }
}

function Update-MetaDisplay {
    if ($null -ne $lblLastCommandValue) {
        Set-LabelText -Label $lblLastCommandValue -Text ([string]$script:LastCommand)
    }

    if ($null -ne $lblLastRefreshValue) {
        if ($script:LastRefreshTime -is [datetime] -and $script:LastRefreshTime -gt [datetime]::MinValue) {
            Set-LabelText -Label $lblLastRefreshValue -Text ($script:LastRefreshTime.ToString('HH:mm:ss'))
        } else {
            Set-LabelText -Label $lblLastRefreshValue -Text '-'
        }
    }
}

function Get-AutoStateText {
    if (Test-IsPendingRelease) {
        $remaining = [int][Math]::Ceiling(($script:CpuAutoReleasePendingUntil - (Get-Date)).TotalSeconds)
        if ($remaining -lt 0) { $remaining = 0 }
        return ('Hold {0}s' -f $remaining)
    }

    if ($script:CpuAutoLatched) {
        return 'Latched 100%'
    }

    if ($script:ManualForceEnabled) {
        return 'Manual 100%'
    }

    if ($script:CpuAutoEnabled) {
        return 'Armed'
    }

    return 'Dell Auto'
}

function Send-MaxFansCore {
    $ok = $false

    try {
        $ok = Set-FullSpeedMode
    } catch {
        $ok = $false
    }

    if (-not $ok) {
        [void](Set-CustomMode)
        $ok1 = Set-FanPercent -FanId $script:CpuFanId -Percent 100
        $ok2 = Set-FanPercent -FanId $script:GpuFanId -Percent 100
        $ok = ($ok1 -and $ok2)
    }

    if (-not $ok) {
        throw 'Unable to force maximum fan speed.'
    }
}

function Send-AutoCore {
    if (-not (Set-BalancedMode)) {
        throw 'Unable to return fans to automatic mode.'
    }
}

function Enable-MaxFans {
    Send-MaxFansCore

    # Manual mode must disable CPU auto logic and cancel any active hold countdown.
    $script:CpuAutoEnabled = $false
    Clear-PendingRelease
    $script:CpuAutoLatched = $false
    $script:ManualForceEnabled = $true
    $script:LastCommand = 'Force 100%'

    Update-StatusBar -Text 'Manual 100% fan mode enabled. CPU load auto disabled.'
    Update-MetaDisplay
    Update-AutoButtonText
    Update-StateBadge -StateText (Get-AutoStateText)
}

function Release-ToAuto {
    Send-AutoCore

    # Returning to automatic mode must disable CPU auto logic and cancel any active hold countdown.
    $script:CpuAutoEnabled = $false
    Clear-PendingRelease
    $script:CpuAutoLatched = $false
    $script:ManualForceEnabled = $false
    $script:LastCommand = 'Return to Auto'

    Update-StatusBar -Text 'Returned fan control to Dell automatic mode. CPU load auto disabled.'
    Update-MetaDisplay
    Update-AutoButtonText
    Update-StateBadge -StateText (Get-AutoStateText)
}

function Toggle-CpuAutoMode {
    $script:CpuAutoEnabled = -not $script:CpuAutoEnabled

    if (-not $script:CpuAutoEnabled) {
        Clear-PendingRelease
        $script:CpuAutoLatched = $false
        $script:ManualForceEnabled = $false
        Send-AutoCore
        $script:LastCommand = 'CPU Auto OFF'
        Update-StatusBar -Text 'CPU load auto control disabled. Returned to Dell automatic mode.'
    } else {
        Clear-PendingRelease
        $script:CpuAutoLatched = $false
        $script:ManualForceEnabled = $false
        Send-AutoCore
        $script:LastCommand = 'CPU Auto ON'
        Update-StatusBar -Text ('CPU load auto control enabled. Enter: {0}% | Exit: {1}% | Hold: {2}s.' -f [int]$script:CpuAutoEnterThreshold, [int]$script:CpuAutoExitThreshold, $script:CpuAutoReleaseHoldSeconds)
    }

    Update-AutoButtonText
    Update-StateBadge -StateText (Get-AutoStateText)
    Update-MetaDisplay
    Refresh-RpmStatus
}

function Evaluate-CpuAuto {
    param([double]$CpuLoad)

    if (-not $script:CpuAutoEnabled) {
        return
    }

    if (-not $script:CpuAutoLatched) {
        if ($CpuLoad -ge $script:CpuAutoEnterThreshold) {
            Send-MaxFansCore
            $script:CpuAutoLatched = $true
            $script:ManualForceEnabled = $false
            Clear-PendingRelease
            $script:LastCommand = 'CPU Auto -> Force 100%'
            Update-StatusBar -Text 'CPU load auto control locked fans at 100%.'
            Update-MetaDisplay
        }
        return
    }

    if (Test-IsPendingRelease) {
        if ($CpuLoad -ge $script:CpuAutoEnterThreshold) {
            Clear-PendingRelease
            $script:LastCommand = 'CPU Auto -> Hold cancelled'
            Update-StatusBar -Text 'Hold countdown cancelled; staying at 100% fan speed.'
            Update-MetaDisplay
            return
        }

        if ((Get-Date) -ge $script:CpuAutoReleasePendingUntil) {
            Send-AutoCore
            $script:CpuAutoLatched = $false
            $script:ManualForceEnabled = $false
            Clear-PendingRelease
            $script:LastCommand = 'CPU Auto -> Release to Auto'
            Update-StatusBar -Text 'Hold elapsed; returned fan control to automatic mode.'
            Update-MetaDisplay
        }
        return
    }

    if ($CpuLoad -le $script:CpuAutoExitThreshold) {
        $script:CpuAutoReleasePendingUntil = (Get-Date).AddSeconds([int]$script:CpuAutoReleaseHoldSeconds)
        $script:LastCommand = 'CPU Auto -> Hold started'
        Update-StatusBar -Text ('Exit threshold reached. Holding 100% fan speed for {0}s.' -f $script:CpuAutoReleaseHoldSeconds)
        Update-MetaDisplay
    }
}

function Refresh-RpmStatus {
    if ($script:IsBusy) { return }

    $script:IsBusy = $true
    try {
        $script:LastRefreshTime = Get-Date

        $cpuLoad = Get-CpuLoadValue
        Evaluate-CpuAuto -CpuLoad $cpuLoad

        $cpu = Get-FanRpm -FanId $script:CpuFanId
        $gpu = Get-FanRpm -FanId $script:GpuFanId

        Update-Peaks -CpuRpm $cpu -GpuRpm $gpu

        Set-LabelText -Label $lblCpuRpmValue -Text ($(if ($null -ne $cpu) { [string][int]$cpu } else { '-' }))
        Set-LabelText -Label $lblGpuRpmValue -Text ($(if ($null -ne $gpu) { [string][int]$gpu } else { '-' }))
        Set-LabelText -Label $lblCpuPctBox -Text (Get-PercentOfReference -Current $cpu -Reference $script:KnownMaxFanRpm)
        Set-LabelText -Label $lblGpuPctBox -Text (Get-PercentOfReference -Current $gpu -Reference $script:KnownMaxFanRpm)
        Set-LabelText -Label $lblCpuPeakValue -Text (Format-RpmVsKnownMax -RpmValue $script:ObservedPeakCpuRpm)
        Set-LabelText -Label $lblGpuPeakValue -Text (Format-RpmVsKnownMax -RpmValue $script:ObservedPeakGpuRpm)
        Set-LabelText -Label $lblCpuLoadValue -Text ('{0:N1} %' -f $cpuLoad)

        Update-StateBadge -StateText (Get-AutoStateText)
        Update-MetaDisplay
    } catch {
        Update-StatusBar -Text ("RPM refresh error: " + $_.Exception.Message)
    } finally {
        $script:IsBusy = $false
    }
}

function Reset-Peaks {
    $script:ObservedPeakCpuRpm = 0
    $script:ObservedPeakGpuRpm = 0
    $script:LastCommand = 'Reset peaks'
    Update-StatusBar -Text 'Observed peak RPM counters reset.'
    Update-MetaDisplay
    Refresh-RpmStatus
}

function Restore-OriginalFanControlOnExit {
    try {
        $script:CpuAutoEnabled = $false
        $script:CpuAutoLatched = $false
        $script:ManualForceEnabled = $false
        Clear-PendingRelease
        Send-AutoCore
        $script:LastCommand = 'Exit -> Release to Auto'
    } catch {}
}

# ---------------------------------------------------------------------
# UI
# ---------------------------------------------------------------------
$form = New-Object System.Windows.Forms.Form
$form.SuspendLayout()
$form.Text = $script:AppName
$form.StartPosition = 'CenterScreen'
$form.Size = New-Object System.Drawing.Size(860, 638)
$form.MinimumSize = New-Object System.Drawing.Size(860, 640)
$form.FormBorderStyle = 'FixedDialog'
$form.MaximizeBox = $false
$form.BackColor = $script:ColorAppBg
$form.ForeColor = $script:ColorTextPrimary
$form.Font = $script:FontUi
Set-DoubleBuffered -Control $form

$lblHeaderTitle = New-Object System.Windows.Forms.Label
$lblHeaderTitle.Text = 'Dell G15 Fan Control'
$lblHeaderTitle.Location = New-Object System.Drawing.Point(20, 16)
$lblHeaderTitle.Size = New-Object System.Drawing.Size(360, 28)
$lblHeaderTitle.Font = $script:FontTitle
$lblHeaderTitle.ForeColor = $script:ColorTextPrimary
$lblHeaderTitle.BackColor = $script:ColorAppBg

$lblHeaderSub = New-Object System.Windows.Forms.Label
$lblHeaderSub.Text = 'Manual fan override, configurable CPU-load auto control, and lightweight live telemetry.'
$lblHeaderSub.Location = New-Object System.Drawing.Point(22, 46)
$lblHeaderSub.Size = New-Object System.Drawing.Size(560, 22)
$lblHeaderSub.Font = $script:FontUi
$lblHeaderSub.ForeColor = $script:ColorTextMuted
$lblHeaderSub.BackColor = $script:ColorAppBg

$actionPanel = New-CardPanel -Title 'Control Actions' -X 20 -Y 80 -Width 810 -Height 92
$btnForce100 = New-ModernButton -Text 'Force 100%: OFF' -X 18 -Y 50 -Width 180 -Height 30 -BackColor $script:ColorButtonDark -ForeColor $script:ColorTextPrimary
$btnReleaseAuto = New-ModernButton -Text 'Return to Auto: OFF' -X 210 -Y 50 -Width 180 -Height 30 -BackColor $script:ColorButtonDark -ForeColor $script:ColorTextPrimary
$btnCpuAuto = New-ModernButton -Text 'CPU Load Auto: ON' -X 402 -Y 50 -Width 190 -Height 30 -BackColor $script:ColorAccent -ForeColor $script:ColorTextPrimary
$btnResetPeaks = New-ModernButton -Text 'Reset peak RPM' -X 604 -Y 50 -Width 188 -Height 30 -BackColor $script:ColorButtonDark -ForeColor $script:ColorTextPrimary
$actionPanel.Controls.AddRange(@($btnForce100, $btnReleaseAuto, $btnCpuAuto, $btnResetPeaks))

$telemetryPanel = New-CardPanel -Title 'Live Telemetry' -X 20 -Y 188 -Width 390 -Height 222
$lblCpuRpm = New-InfoLabel -Text 'CPU Fan RPM' -X 18 -Y 58 -Width 120
$lblCpuRpmValue = New-ValueLabel -Text '-' -X 170 -Y 58 -Width 95
$lblCpuPctBox = New-ReadoutBox -Text '-' -X 272 -Y 56 -Width 88
$lblGpuRpm = New-InfoLabel -Text 'GPU Fan RPM' -X 18 -Y 90 -Width 120
$lblGpuRpmValue = New-ValueLabel -Text '-' -X 170 -Y 90 -Width 95
$lblGpuPctBox = New-ReadoutBox -Text '-' -X 272 -Y 88 -Width 88
$lblCpuLoad = New-InfoLabel -Text 'CPU Load' -X 18 -Y 122 -Width 120
$lblCpuLoadValue = New-ValueLabel -Text '-' -X 170 -Y 122 -Width 190
$lblAutoState = New-InfoLabel -Text 'Auto state' -X 18 -Y 154 -Width 120
$lblAutoStateValue = New-ValueLabel -Text 'Armed' -X 170 -Y 154 -Width 190
$telemetryPanel.Controls.AddRange(@(
    $lblCpuRpm, $lblCpuRpmValue, $lblCpuPctBox,
    $lblGpuRpm, $lblGpuRpmValue, $lblGpuPctBox,
    $lblCpuLoad, $lblCpuLoadValue,
    $lblAutoState, $lblAutoStateValue
))

$statsPanel = New-CardPanel -Title 'Observed Peaks & Activity' -X 440 -Y 188 -Width 390 -Height 222
$lblCpuPeak = New-InfoLabel -Text 'CPU Peak RPM' -X 18 -Y 58 -Width 120
$lblCpuPeakValue = New-ValueLabel -Text '-' -X 180 -Y 58 -Width 190
$lblGpuPeak = New-InfoLabel -Text 'GPU Peak RPM' -X 18 -Y 90 -Width 120
$lblGpuPeakValue = New-ValueLabel -Text '-' -X 180 -Y 90 -Width 190
$lblLastCommand = New-InfoLabel -Text 'Last action' -X 18 -Y 122 -Width 120
$lblLastCommandValue = New-ValueLabel -Text 'Application started' -X 180 -Y 122 -Width 210
$lblLastRefresh = New-InfoLabel -Text 'Last update' -X 18 -Y 154 -Width 120
$lblLastRefreshValue = New-ValueLabel -Text '-' -X 180 -Y 154 -Width 190
$statsPanel.Controls.AddRange(@(
    $lblCpuPeak, $lblCpuPeakValue,
    $lblGpuPeak, $lblGpuPeakValue,
    $lblLastCommand, $lblLastCommandValue,
    $lblLastRefresh, $lblLastRefreshValue
))

$configPanel = New-CardPanel -Title 'Control Settings' -X 20 -Y 426 -Width 810 -Height 122

$settingsCard1 = New-Object System.Windows.Forms.Panel
$settingsCard1.Location = New-Object System.Drawing.Point(20, 50)
$settingsCard1.Size = New-Object System.Drawing.Size(236, 54)
$settingsCard1.BackColor = $script:ColorInputBg
$settingsCard1.BorderStyle = 'FixedSingle'

$settingsCard2 = New-Object System.Windows.Forms.Panel
$settingsCard2.Location = New-Object System.Drawing.Point(287, 50)
$settingsCard2.Size = New-Object System.Drawing.Size(236, 54)
$settingsCard2.BackColor = $script:ColorInputBg
$settingsCard2.BorderStyle = 'FixedSingle'

$settingsCard3 = New-Object System.Windows.Forms.Panel
$settingsCard3.Location = New-Object System.Drawing.Point(554, 50)
$settingsCard3.Size = New-Object System.Drawing.Size(236, 54)
$settingsCard3.BackColor = $script:ColorInputBg
$settingsCard3.BorderStyle = 'FixedSingle'

$lblRefreshInterval = New-Object System.Windows.Forms.Label
$lblRefreshInterval.Text = 'Refresh interval (ms)'
$lblRefreshInterval.Location = New-Object System.Drawing.Point(12, 8)
$lblRefreshInterval.Size = New-Object System.Drawing.Size(150, 18)
$lblRefreshInterval.Font = $script:FontUi
$lblRefreshInterval.ForeColor = $script:ColorTextMuted
$lblRefreshInterval.BackColor = $script:ColorInputBg

$numRefreshInterval = New-Object System.Windows.Forms.NumericUpDown
$numRefreshInterval.Location = New-Object System.Drawing.Point(12, 26)
$numRefreshInterval.Size = New-Object System.Drawing.Size(110, 24)
$numRefreshInterval.Minimum = 250
$numRefreshInterval.Maximum = 5000
$numRefreshInterval.Increment = 250
$numRefreshInterval.Value = 500
$numRefreshInterval.Font = $script:FontUi
$numRefreshInterval.BackColor = $script:ColorInputBg
$numRefreshInterval.ForeColor = $script:ColorTextPrimary
$numRefreshInterval.BorderStyle = 'FixedSingle'

$lblAutoHold = New-Object System.Windows.Forms.Label
$lblAutoHold.Text = 'Auto release hold (s)'
$lblAutoHold.Location = New-Object System.Drawing.Point(12, 8)
$lblAutoHold.Size = New-Object System.Drawing.Size(160, 18)
$lblAutoHold.Font = $script:FontUi
$lblAutoHold.ForeColor = $script:ColorTextMuted
$lblAutoHold.BackColor = $script:ColorInputBg

$comboAutoHold = New-Object System.Windows.Forms.ComboBox
$comboAutoHold.Location = New-Object System.Drawing.Point(12, 26)
$comboAutoHold.Size = New-Object System.Drawing.Size(110, 24)
$comboAutoHold.DropDownStyle = 'DropDownList'
$comboAutoHold.Font = $script:FontUi
$comboAutoHold.BackColor = $script:ColorInputBg
$comboAutoHold.ForeColor = $script:ColorTextPrimary
$comboAutoHold.FlatStyle = 'Flat'

$lblThresholdTitle = New-Object System.Windows.Forms.Label
$lblThresholdTitle.Text = 'CPU auto thresholds'
$lblThresholdTitle.Location = New-Object System.Drawing.Point(12, 6)
$lblThresholdTitle.Size = New-Object System.Drawing.Size(170, 18)
$lblThresholdTitle.Font = $script:FontUi
$lblThresholdTitle.ForeColor = $script:ColorTextMuted
$lblThresholdTitle.BackColor = $script:ColorInputBg

$lblEnterMini = New-Object System.Windows.Forms.Label
$lblEnterMini.Text = 'Enter'
$lblEnterMini.Location = New-Object System.Drawing.Point(12, 30)
$lblEnterMini.Size = New-Object System.Drawing.Size(36, 18)
$lblEnterMini.Font = $script:FontUi
$lblEnterMini.ForeColor = $script:ColorTextMuted
$lblEnterMini.BackColor = $script:ColorInputBg

$comboEnterThreshold = New-Object System.Windows.Forms.ComboBox
$comboEnterThreshold.Location = New-Object System.Drawing.Point(50, 26)
$comboEnterThreshold.Size = New-Object System.Drawing.Size(66, 24)
$comboEnterThreshold.DropDownStyle = 'DropDownList'
$comboEnterThreshold.Font = $script:FontUi
$comboEnterThreshold.BackColor = $script:ColorInputBg
$comboEnterThreshold.ForeColor = $script:ColorTextPrimary
$comboEnterThreshold.FlatStyle = 'Flat'

$lblExitMini = New-Object System.Windows.Forms.Label
$lblExitMini.Text = 'Exit'
$lblExitMini.Location = New-Object System.Drawing.Point(126, 30)
$lblExitMini.Size = New-Object System.Drawing.Size(26, 18)
$lblExitMini.Font = $script:FontUi
$lblExitMini.ForeColor = $script:ColorTextMuted
$lblExitMini.BackColor = $script:ColorInputBg

$comboExitThreshold = New-Object System.Windows.Forms.ComboBox
$comboExitThreshold.Location = New-Object System.Drawing.Point(156, 26)
$comboExitThreshold.Size = New-Object System.Drawing.Size(66, 24)
$comboExitThreshold.DropDownStyle = 'DropDownList'
$comboExitThreshold.Font = $script:FontUi
$comboExitThreshold.BackColor = $script:ColorInputBg
$comboExitThreshold.ForeColor = $script:ColorTextPrimary
$comboExitThreshold.FlatStyle = 'Flat'

foreach ($sec in $script:CpuAutoReleaseHoldOptions) {
    [void]$comboAutoHold.Items.Add([string][int]$sec)
}
foreach ($thr in $script:CpuAutoEnterThresholdOptions) {
    [void]$comboEnterThreshold.Items.Add([string][int]$thr)
}
foreach ($thr in $script:CpuAutoExitThresholdOptions) {
    [void]$comboExitThreshold.Items.Add([string][int]$thr)
}

$settingsCard1.Controls.AddRange(@($lblRefreshInterval, $numRefreshInterval))
$settingsCard2.Controls.AddRange(@($lblAutoHold, $comboAutoHold))
$settingsCard3.Controls.AddRange(@($lblThresholdTitle, $lblEnterMini, $comboEnterThreshold, $lblExitMini, $comboExitThreshold))

$configPanel.Controls.AddRange(@(
    $settingsCard1,
    $settingsCard2,
    $settingsCard3
))

$statusPanel = New-Object System.Windows.Forms.Panel
$statusPanel.Location = New-Object System.Drawing.Point(20, 562)
$statusPanel.Size = New-Object System.Drawing.Size(810, 28)
$statusPanel.BackColor = [System.Drawing.Color]::FromArgb(26, 28, 32)
$statusPanel.BorderStyle = 'FixedSingle'

$lblStatus = New-Object System.Windows.Forms.Label
$lblStatus.Text = 'Ready.'
$lblStatus.Location = New-Object System.Drawing.Point(12, 4)
$lblStatus.Size = New-Object System.Drawing.Size(780, 20)
$lblStatus.Font = $script:FontUi
$lblStatus.ForeColor = $script:ColorTextPrimary
$lblStatus.BackColor = $statusPanel.BackColor
$statusPanel.Controls.Add($lblStatus)

$form.Controls.AddRange(@(
    $lblHeaderTitle,
    $lblHeaderSub,
    $actionPanel,
    $telemetryPanel,
    $statsPanel,
    $configPanel,
    $statusPanel
))

$timer = New-Object System.Windows.Forms.Timer
$timer.Interval = 500
$timer.add_Tick({
    Refresh-RpmStatus
})

$numRefreshInterval.add_ValueChanged({
    $timer.Interval = [int]$numRefreshInterval.Value
    Update-StatusBar -Text ('Refresh interval set to {0} ms.' -f [int]$numRefreshInterval.Value)
})

$comboAutoHold.add_SelectedIndexChanged({
    if ($null -ne $comboAutoHold.SelectedItem) {
        $script:CpuAutoReleaseHoldSeconds = [int]$comboAutoHold.SelectedItem
        if ($script:CpuAutoEnabled) {
            Update-StatusBar -Text ('CPU auto release hold set to {0}s.' -f $script:CpuAutoReleaseHoldSeconds)
        }
    }
})

$comboEnterThreshold.add_SelectedIndexChanged({
    if ($null -ne $comboEnterThreshold.SelectedItem) {
        $script:CpuAutoEnterThreshold = [double][int]$comboEnterThreshold.SelectedItem
        if ($script:CpuAutoEnabled) {
            Update-StatusBar -Text ('CPU auto enter threshold set to {0}%. Exit is {1}%.' -f [int]$script:CpuAutoEnterThreshold, [int]$script:CpuAutoExitThreshold)
        }
    }
})

$comboExitThreshold.add_SelectedIndexChanged({
    if ($null -ne $comboExitThreshold.SelectedItem) {
        $script:CpuAutoExitThreshold = [double][int]$comboExitThreshold.SelectedItem
        if ($script:CpuAutoEnabled) {
            Update-StatusBar -Text ('CPU auto exit threshold set to {0}%. Enter is {1}%.' -f [int]$script:CpuAutoExitThreshold, [int]$script:CpuAutoEnterThreshold)
        }
    }
})

$btnForce100.add_Click({
    try {
        $timer.Stop()
        Enable-MaxFans
        Refresh-RpmStatus
    } catch {
        [System.Windows.Forms.MessageBox]::Show(
            $_.Exception.Message,
            $script:AppName,
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Error
        ) | Out-Null
    } finally {
        $timer.Start()
    }
})

$btnReleaseAuto.add_Click({
    try {
        $timer.Stop()
        Release-ToAuto
        Refresh-RpmStatus
    } catch {
        [System.Windows.Forms.MessageBox]::Show(
            $_.Exception.Message,
            $script:AppName,
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Error
        ) | Out-Null
    } finally {
        $timer.Start()
    }
})

$btnCpuAuto.add_Click({
    try {
        $timer.Stop()
        Toggle-CpuAutoMode
    } catch {
        [System.Windows.Forms.MessageBox]::Show(
            $_.Exception.Message,
            $script:AppName,
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Error
        ) | Out-Null
    } finally {
        $timer.Start()
    }
})

$btnResetPeaks.add_Click({
    try {
        $timer.Stop()
        Reset-Peaks
    } catch {
        [System.Windows.Forms.MessageBox]::Show(
            $_.Exception.Message,
            $script:AppName,
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Error
        ) | Out-Null
    } finally {
        $timer.Start()
    }
})

$form.add_Shown({
    try {
        Initialize-CpuCounter
        Initialize-AutoUiState

        $defaultHoldString = [string][int]$script:CpuAutoReleaseHoldDefault
        if (-not $comboAutoHold.Items.Contains($defaultHoldString)) {
            [void]$comboAutoHold.Items.Add($defaultHoldString)
        }

        $comboAutoHold.SelectedItem = $defaultHoldString
        $script:CpuAutoReleaseHoldSeconds = [int]$comboAutoHold.SelectedItem

        $defaultEnterString = [string][int]$script:CpuAutoEnterThresholdDefault
        if (-not $comboEnterThreshold.Items.Contains($defaultEnterString)) {
            [void]$comboEnterThreshold.Items.Add($defaultEnterString)
        }

        $comboEnterThreshold.SelectedItem = $defaultEnterString
        $script:CpuAutoEnterThreshold = [double][int]$comboEnterThreshold.SelectedItem

        $defaultExitString = [string][int]$script:CpuAutoExitThresholdDefault
        if (-not $comboExitThreshold.Items.Contains($defaultExitString)) {
            [void]$comboExitThreshold.Items.Add($defaultExitString)
        }
        $comboExitThreshold.SelectedItem = $defaultExitString
        $script:CpuAutoExitThreshold = [double][int]$comboExitThreshold.SelectedItem

        $script:LastCommand = 'Application started'
        $script:LastRefreshTime = Get-Date
        Update-MetaDisplay
        Refresh-RpmStatus
        $timer.Start()
    } catch {
        Update-StatusBar -Text $_.Exception.Message
    }
})

$form.add_FormClosing({
    try { $timer.Stop() } catch {}
    try { Restore-OriginalFanControlOnExit } catch {}
    try {
        if ($null -ne $script:CpuCounter) {
            $script:CpuCounter.Dispose()
        }
    } catch {}

    try {
        $script:FontUi.Dispose()
        $script:FontUiBold.Dispose()
        $script:FontTitle.Dispose()
        $script:FontCardTitle.Dispose()
        $script:FontValue.Dispose()
    } catch {}
})

$form.ResumeLayout($false)
[void]$form.ShowDialog()