# Remove-ClassicTeams.ps1
# Removes classic Microsoft Teams and Teams Machine-Wide Installer.
# Leaves new Teams / MSTeams MSIX app installed.

$ErrorActionPreference = "Continue"

Write-Output "Starting classic Teams cleanup..."

# Stop Teams-related processes
$processNames = @(
    "Teams",
    "ms-teams",
    "msteams",
    "Microsoft.Teams",
    "Update"
)

foreach ($process in $processNames) {
    Get-Process -Name $process -ErrorAction SilentlyContinue |
        Stop-Process -Force -ErrorAction SilentlyContinue
}

Start-Sleep -Seconds 5

# Remove Teams Machine-Wide Installer from HKLM uninstall registry
$uninstallPaths = @(
    "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*",
    "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*"
)

$machineWideInstallers = foreach ($path in $uninstallPaths) {
    Get-ItemProperty $path -ErrorAction SilentlyContinue | Where-Object {
        $_.DisplayName -eq "Teams Machine-Wide Installer"
    }
}

foreach ($app in $machineWideInstallers) {
    Write-Output "Found Teams Machine-Wide Installer: $($app.DisplayName) $($app.DisplayVersion)"

    if ($app.UninstallString -match "\{[A-Fa-f0-9\-]{36}\}") {
        $productCode = $Matches[0]
        Write-Output "Removing Teams Machine-Wide Installer using MSI product code: $productCode"
        Start-Process -FilePath "msiexec.exe" -ArgumentList "/x $productCode /qn /norestart" -Wait
    }
    elseif ($app.UninstallString) {
        Write-Output "Attempting uninstall using uninstall string: $($app.UninstallString)"
        Start-Process -FilePath "cmd.exe" -ArgumentList "/c $($app.UninstallString) /quiet /norestart" -Wait
    }
}

# Remove classic Teams per-user installs
$userProfiles = Get-ChildItem "C:\Users" -Directory -ErrorAction SilentlyContinue | Where-Object {
    $_.Name -notin @(
        "Public",
        "Default",
        "Default User",
        "All Users",
        "defaultuser0"
    )
}

foreach ($profile in $userProfiles) {
    $teamsFolder = Join-Path $profile.FullName "AppData\Local\Microsoft\Teams"
    $updateExe = Join-Path $teamsFolder "Update.exe"

    if (Test-Path $updateExe) {
        Write-Output "Uninstalling classic Teams for profile: $($profile.Name)"
        Start-Process -FilePath $updateExe -ArgumentList "--uninstall -s" -Wait -ErrorAction SilentlyContinue
        Start-Sleep -Seconds 3
    }

    if (Test-Path $teamsFolder) {
        Write-Output "Removing remaining classic Teams folder for profile: $($profile.Name)"
        Remove-Item -Path $teamsFolder -Recurse -Force -ErrorAction SilentlyContinue
    }
}

# Remove common classic Teams leftovers
$leftoverPaths = @(
    "$env:ProgramData\Microsoft\Teams",
    "$env:ProgramData\Microsoft\TeamsMachineInstaller"
)

foreach ($path in $leftoverPaths) {
    if (Test-Path $path) {
        Write-Output "Removing leftover path: $path"
        Remove-Item -Path $path -Recurse -Force -ErrorAction SilentlyContinue
    }
}

# Confirm new Teams remains installed
$newTeams = Get-AppxPackage -AllUsers | Where-Object {
    $_.Name -eq "MSTeams"
}

if ($newTeams) {
    Write-Output "New Teams detected and left installed:"
    $newTeams | Select-Object Name, Version, PackageFullName | Format-List | Out-String | Write-Output
}
else {
    Write-Output "WARNING: New Teams / MSTeams was not detected after cleanup."
}

# Final verification for classic Teams entries
$remainingMachineWide = foreach ($path in $uninstallPaths) {
    Get-ItemProperty $path -ErrorAction SilentlyContinue | Where-Object {
        $_.DisplayName -eq "Teams Machine-Wide Installer"
    }
}

$remainingClassicFolders = foreach ($profile in $userProfiles) {
    $teamsFolder = Join-Path $profile.FullName "AppData\Local\Microsoft\Teams"
    if (Test-Path $teamsFolder) {
        $teamsFolder
    }
}

if ($remainingMachineWide -or $remainingClassicFolders) {
    Write-Output "Classic Teams cleanup completed, but some remnants may remain."
    if ($remainingMachineWide) {
        $remainingMachineWide | Select-Object DisplayName, DisplayVersion | Format-Table | Out-String | Write-Output
    }
    if ($remainingClassicFolders) {
        $remainingClassicFolders | ForEach-Object { Write-Output "Remaining folder: $_" }
    }
    exit 1
}
else {
    Write-Output "Classic Teams and Teams Machine-Wide Installer cleanup completed successfully."
    exit 0
}