MeetingRoomsSeriesRoutine.ps1

#Enter email account you want to send email reminders from
$Email = "enter email here"

#Enter Logicapp URL
$LogicAppURL = "enter webhook url here"


#If subject is hidden in meeting room calendar, set this to true so we get the subject from organizers calendar instead.
$HiddenSubject = $true

$stopwatch = [System.Diagnostics.Stopwatch]::new()
$stopwatch.Start()
    function AuthenticationFunction {

        Connect-AzAccount -Identity -ErrorAction Stop | Out-Null
        $AccessToken = Get-AzAccessToken -ResourceTypeName MSGraph -ErrorAction Stop | select -ExpandProperty Token
        $global:Header = @{"Authorization" = "Bearer $AccessToken" }



        $stopwatch = [System.Diagnostics.Stopwatch]::new()
        $Stopwatch.Start()
   
    }

AuthenticationFunction

#Gets all meetingrooms.
$uri = "https://graph.microsoft.com/v1.0/places/microsoft.graph.room?`$top=5000"


$Rooms = while (-not [string]::IsNullOrEmpty($uri)) {
   # API Call
   # Write-Host "`r`nQuerying $currentUri..." -ForegroundColor Yellow
    $apiCall = Invoke-WebRequest -Method "GET" -Uri $uri -ContentType "application/json" -Headers $global:Header -ErrorAction Stop -UseBasicParsing
    $nextLink = $null
    $uri = $null
    
    if ($apiCall.Content) {
        # Check if any data is left
        $nextLink = $apiCall.Content | ConvertFrom-Json | Select-Object '@odata.nextLink'
        $uri = $nextLink.'@odata.nextLink'
        $apiCall.Content | ConvertFrom-Json
    }
}




$MeetingSeriesList = @()
Foreach($room in $rooms.value){

    If($stopwatch.Elapsed.Minutes -gt 40){
        AuthenticationFunction
    }
    
    $RoomUPN = $room.emailaddress
    $RoomDisplayName = $room.displayName
    $Today = ((Get-Date).Date)

    $endDate = $Today.AddDays(10)

    $startDate = get-date $today -Format "yyyy-MM-dd"
    $endDate = get-date $endDate -Format "yyyy-MM-dd"
    $startDateinstance = get-date $Today -Format "yyyy-MM-dd"

    $uri = "https://graph.microsoft.com/v1.0/users/$RoomUPN/calendarview?startDateTime=$($startDate)T00:00:00.0000000&endDateTime=$($endDate)T23:59:00.0000000"
    
    $meetings = while (-not [string]::IsNullOrEmpty($uri)) {
        #API Call
        $apiCall = Invoke-WebRequest -Method "GET" -Uri $uri -ContentType "application/json" -Headers $global:Header -ErrorAction Stop -UseBasicParsing
        $nextLink = $null
        $uri = $null
        
        if ($apiCall.Content) {
            # Check if any data is left
            $nextLink = $apiCall.Content | ConvertFrom-Json | Select-Object '@odata.nextLink'
            $uri = $nextLink.'@odata.nextLink'
            $apiCall.Content | ConvertFrom-Json
        }
    }

 

    $meetings.value | ForEach-Object {
        
            $tempDateStart =(Get-Date $($_.Start.datetime)).ToUniversalTime()            
            $tempDateEnd =(Get-Date $($_.end.datetime)).ToUniversalTime()
            $tzEST = [System.TimeZoneInfo]::FindSystemTimeZoneById("$($_.originalStartTimeZone)")
            $CurrentTimeStart = [System.TimeZoneInfo]::ConvertTimeFromUtc($tempDateStart, $tzEST)
            $CurrentTimeEnd = [System.TimeZoneInfo]::ConvertTimeFromUtc($tempDateEnd, $tzEST)
            $OrganizerDateStart = (Get-Date $($_.Start.datetime) -Format o).split("+")[0]
            $OrganizerDateStart = get-date $OrganizerDateStart -Format "yyyy-MM-dd"


            $iCalUId = @()
            $iCalUId = $_.iCalUId

            $uri = "https://graph.microsoft.com/v1.0/users/$($_.organizer.emailAddress.address)/calendarview?startDateTime=$($OrganizerDateStart)T00:00:00.0000000&endDateTime=$($OrganizerDateStart)T23:59:00.0000000"
        

            $Subject = @()

            if($HiddenSubject -eq $true){
            $Subject = ((Invoke-RestMethod -Uri $uri -Headers $global:Header).Value | Where-Object{$_.iCalUId -like $iCalUId}).Subject
            $Subject=$Subject.Replace("'","")
            }
            else{
                $Subject = $_.Subject
            }
            #Write-Output $Subject
            
            $TempMeetingSeriesList = [PSCustomObject]@{
                Subject = $Subject
                Date = $(Get-Date $CurrentTimeStart -Format "yyyy-MM-dd")
                StartTime = $(Get-date $CurrentTimeStart -Format "HH:mm")
                EndTime = $(Get-date $CurrentTimeEnd -Format "HH:mm")
                ID = $_.ID
                MeetingRoomUPN = $RoomUPN
                MeetingRoomDisplayName = $RoomDisplayName
                OrganizerUPN = $_.organizer.emailAddress.address
                OrganizerName = $_.organizer.emailAddress.name         
            }
            $MeetingSeriesList += $TempMeetingSeriesList
    }
}

$MeetingSeriesList = $MeetingSeriesList | Group-Object ID|   %{ $_.Group | Select 'Subject','Date', 'StartTime', 'EndTime', 'ID', 'MeetingRoomUPN', 'MeetingRoomDisplayName', 'OrganizerUPN', 'OrganizerName' -First 1}

$Today = (Get-Date).date
$Sunday = Get-Date ($Today.AddDays(1)) -Format yyyy-MM-dd
$NextSunday = Get-Date ($Today.AddDays(8)) -Format yyyy-MM-dd

#Finds all unique meeting organizers.
$users = $MeetingSeriesList | Select-Object OrganizerUPN,OrganizerName -Unique


#Find all the meetingrooms a organizer have booked this week, and send email with reminder to see if any rooms can be canceled.
foreach($user in $users){
    If($stopwatch.Elapsed.Minutes -gt 40){
        AuthenticationFunction
    }


        $EventsThisWeek = @()
        $bodyHTML = @()

        $EventsThisWeek = $MeetingSeriesList | Where-Object{$_.date -ge $sunday -and $_.date -lt $NextSunday -and $_.organizerupn -like $user.organizerupn}

        If($EventsThisWeek){
            #$EventsThisWeek | ft
                $Title="Here are your meeting room bookings for this week."
                $bodyHTML ='<doctype html><html><head><title>' + $Title +' </title></head><body><font face="Calibri" size="3">'
                $bodyHTML+="<p>Hi $($user.OrganizerName)!</p><p>Please cancel any meetingrooms you wont use this week<b><i></i></b>,"
                $bodyHTML+="<table border=1><tr><th>Meeting room</th><th>Booked on</th><th>at Time</th><th>Subject</th><th>Realse Meeting Room</th></tr>"

            foreach($EventThisWeek in $EventsThisWeek){
                $webhookURL = "$LogicAppURL&myString={`"MeetingRoomUPN`": `"$($EventThisWeek.MeetingRoomUPN)`" , `"MeetingID`": `"$($EventThisWeek.ID)`"}"
                $bodyHTML+="<tr><td>$($EventThisWeek.MeetingRoomDisplayName)</td><td>$($EventThisWeek.Date)</td><td>$($EventThisWeek.StartTime) to $($EventThisWeek.EndTime)</td><td>$($EventThisWeek.Subject)</td><td><a href=\'$webhookURL\'>Click here to realse meeting room</a></td></tr>"
            }</table>
#$bodyHTML+="<p>Thanks,</p><p>MWPS COL Team</p>"
$BodyEmail = @"
{
    "message": {
      "subject": "$Title",
      "body": {
        "contentType": "HTML",
        "content": '$bodyHTML'
      },
      "toRecipients": [
        {
          "emailAddress": {
            "address": "$($user.OrganizerUPN)"
          }
        }
      ]
    },
    "saveToSentItems": "false"
  }
"@
Invoke-RestMethod -Method POST -Uri "https://graph.microsoft.com/v1.0/users/$email/sendMail" -Headers $global:Header -body $BodyEmail -ContentType "application/json;charset=utf-8"
}


}