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

    Fault : Double-clicking a file opens Office but not the document
    Fix   : Reset the file association
    Source: https://jbtecwiz.com/support/win-office-dde-blank

    Run as     : PowerShell as the affected user
    Expect     : 20 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    The DDE setting is not the cause, or the wrong program is opening the
    file.

    HOW TO UNDO IT
    Set the default application back through Settings -> Apps -> Default
    apps.

    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.
#>

[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 4"
    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 '  Double-clicking a file opens Office but not the document' -ForegroundColor White
Write-Host '  Reset the file association' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   20 minutes'
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 'Look at the per-user choice Windows is honouring.' -Why 'The per-user choice overrides the machine-wide association. A previous default set by another application -- a viewer, a competing suite, an installer that grabbed the extension -- lives here and survives an Office repair.' -Command {
    Get-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.xlsx\UserChoice' -ErrorAction SilentlyContinue | Select-Object ProgId
}

Invoke-Step -Number 2 -Do 'Remove the per-user override so the machine default applies again.' -Command {
    Remove-Item 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.xlsx\UserChoice' -Force -ErrorAction SilentlyContinue
}

Invoke-Step -Number 3 -Do 'Set the default again through Settings -> Apps -> Default apps, choosing Excel for the extension. Setting it through the interface writes the hash Windows requires; writing ProgId directly does not work on current builds.' -Why 'Windows validates UserChoice with a hash of the user SID, the extension and the ProgId. A value written by hand fails validation and is silently ignored, which is why registry-only fixes for this appear to do nothing.' -Manual

Invoke-Step -Number 4 -Do 'If several extensions are affected, run the Office quick repair, which re-registers all of them at once.' -Command {
    & "$env:CommonProgramFiles\Microsoft Shared\ClickToRun\OfficeClickToRun.exe" scenario=Repair platform=x64 culture=en-us RepairType=QuickRepair DisplayLevel=True
}

Write-Rule "  Confirm it worked"
Show-Prose 'Double-clicking each affected file type opens the right application with the file loaded.' '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-office-dde-blank' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: Set the default application back through Settings -> Apps -> Default apps.' 'DarkGray'
Write-Rule