#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : Teams will not load, shows a white screen, or is stuck signing in
    Fix   : Reset the new Teams and its WebView2 runtime
    Source: https://jbtecwiz.com/support/win-app-teams-cache

    Run as     : PowerShell as the affected user
    Expect     : 25 minutes
    Risk       : medium
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    The Store-based Teams. It is a packaged app, so it resets differently
    from the old one.

    HOW TO UNDO IT
    A reset returns the app to a clean state; chat history is stored in the
    service, not locally.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 5"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  Teams will not load, shows a white screen, or is stuck signing in' -ForegroundColor White
Write-Host '  Reset the new Teams and its WebView2 runtime' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: medium   Reversible   25 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Close Teams completely.' -Command {
    Get-Process ms-teams,msedgewebview2 -ErrorAction SilentlyContinue | Stop-Process -Force
}

Invoke-Step -Number 2 -Do 'Confirm which package is installed.' -Command {
    Get-AppxPackage -Name MSTeams | Format-List Name,Version,InstallLocation,Status
}

Invoke-Step -Number 3 -Do 'Reset the package, which clears its cache without uninstalling it.' -Why 'Reset-AppxPackage is the supported way to clear a packaged app''s state. Deleting folders under Packages by hand can leave the package registered but broken, which is much harder to recover from.' -Command {
    Get-AppxPackage -Name MSTeams | Reset-AppxPackage
}

Invoke-Step -Number 4 -Do 'Check the WebView2 runtime is present and current -- the new Teams is drawn entirely by it.' -Command {
    Get-ItemProperty HKLM:\Software\WOW6432Node\Microsoft\EdgeUpdate\Clients\* -ErrorAction SilentlyContinue |
      Where-Object pv -and $_.name -like '*WebView*' | Format-List name,pv
}

Invoke-Step -Number 5 -Do 'Reinstall the Evergreen WebView2 runtime from Microsoft if it is missing or the version is old.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'Teams opens to the chat list and the account is signed in.' 'White'

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/win-app-teams-cache' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: A reset returns the app to a clean state; chat history is stored in the service, not locally.' 'DarkGray'
Write-Rule