# Connect to Microsoft Teams
$cred = Get-Credential
try {
    Write-Output "Connecting to Microsoft Teams"
    Connect-MicrosoftTeams -Credential $cred | Out-Null
}
catch {
    Write-Output "Unable to connect to Microsoft Teams. $($Error[0].Exception.Message)"
    Return
}

# Get all teams
$AllTeams = Get-Team

# Create empty report object
$FinalReport = @()

# Check channels of each team
ForEach ($SingleTeam in $AllTeams) {
    # Get all shared channels
    try {
        $AllChannels = $null
        $AllChannels = Get-TeamChannel -GroupId $SingleTeam.GroupId -MembershipType Shared
        if ($AllChannels) {
            ForEach ($SingleChannel in $AllChannels) {
                $TeamObject = [PSCustomObject]@{
                    Team           = $SingleTeam.DisplayName
                    Channel        = $SingleChannel.DisplayName
                    MembershipType = $SingleChannel.MembershipType
                }
                $FinalReport += $TeamObject
            }
        }
    }
    catch {
        Write-Output "Failed to get shared channels of $($SingleTeam.DisplayName) team. $($Error[0].Exception.Message)"
        $TeamObject = [PSCustomObject]@{
            Team  = $SingleTeam.DisplayName
            Error = "Failed to get channels of the team. $($Error[0].Exception.Message)"
        }
        $FinalReport += $TeamObject
    }
}

# Print result to the screen
Write-Output $FinalReport | Sort-Object User | Format-Table

# Export result to CSV file if needed
if ($ExportCSV) {
    $FinalReport | Sort-Object User | Export-Csv -Path $ExportFilePath -NoTypeInformation
    Write-Output "Report saved to $ExportFilePath"
}

# Stop before closing powershell window
Read-Host "Script completed. Press 'Enter' to finish"