using namespace System.Net

# Input bindings are passed in via param block.
param($Request, $TriggerMetadata)


# Set-CellColor Function provided by Martin Pugh @ https://community.spiceworks.com/scripts/show/2450-change-cell-color-in-html-table-with-powershell-set-cellcolor
Function Set-CellColor
{ 
    [CmdletBinding()]
    Param (
        [Parameter(Mandatory,Position=0)]
        [string]$Property,
        [Parameter(Mandatory,Position=1)]
        [string]$Color,
        [Parameter(Mandatory,ValueFromPipeline)]
        [Object[]]$InputObject,
        [Parameter(Mandatory)]
        [string]$Filter,
        [switch]$Row
    )
    
    Begin {
        Write-Verbose "$(Get-Date): Function Set-CellColor begins"
        If ($Filter)
        {   If ($Filter.ToUpper().IndexOf($Property.ToUpper()) -ge 0)
            {   $Filter = $Filter.ToUpper().Replace($Property.ToUpper(),"`$Value")
                Try {
                    [scriptblock]$Filter = [scriptblock]::Create($Filter)
                }
                Catch {
                    Write-Warning "$(Get-Date): ""$Filter"" caused an error, stopping script!"
                    Write-Warning $Error[0]
                    Exit
                }
            }
            Else
            {   Write-Warning "Could not locate $Property in the Filter, which is required.  Filter: $Filter"
                Exit
            }
        }
    }
    
    Process {
        ForEach ($Line in $InputObject)
        {   If ($Line.IndexOf("<tr><th") -ge 0)
            {   Write-Verbose "$(Get-Date): Processing headers..."
                $Search = $Line | Select-String -Pattern '<th ?[a-z\-:;"=]*>(.*?)<\/th>' -AllMatches
                $Index = 0
                ForEach ($Match in $Search.Matches)
                {   If ($Match.Groups[1].Value -eq $Property)
                    {   Break
                    }
                    $Index ++
                }
                If ($Index -eq $Search.Matches.Count)
                {   Write-Warning "$(Get-Date): Unable to locate property: $Property in table header"
                    Exit
                }
                Write-Verbose "$(Get-Date): $Property column found at index: $Index"
            }
            If ($Line -match "<tr( style=""background-color:.+?"")?><td")
            {   $Search = $Line | Select-String -Pattern '<td ?[a-z\-:;"=]*>(.*?)<\/td>' -AllMatches
                $Value = $Search.Matches[$Index].Groups[1].Value -as [double]
                If (-not $Value)
                {   $Value = $Search.Matches[$Index].Groups[1].Value
                }
                If (Invoke-Command $Filter)
                {   If ($Row)
                    {   Write-Verbose "$(Get-Date): Criteria met!  Changing row to $Color..."
                        If ($Line -match "<tr style=""background-color:(.+?)"">")
                        {   $Line = $Line -replace "<tr style=""background-color:$($Matches[1])","<tr style=""background-color:$Color"
                        }
                        Else
                        {   $Line = $Line.Replace("<tr>","<tr style=""background-color:$Color"">")
                        }
                    }
                    Else
                    {   Write-Verbose "$(Get-Date): Criteria met!  Changing cell to $Color..."
                        $Line = $Line.Replace($Search.Matches[$Index].Value,"<td style=""background-color:$Color"">$Value</td>")
                    }
                }
            }
            Write-Output $Line
        }
    }
    
    End {
        Write-Verbose "$(Get-Date): Function Set-CellColor completed"
    }
}

Function Get-AZQuotaUsageHTML 
{

# HTML header
$Header = @"
<style>
BODY {font-family:verdana;}
TABLE {border-width: 1px; border-style: solid; border-color: black; border-collapse: collapse;}
TH {border-width: 1px; padding: 3px; border-style: solid; border-color: black; padding: 5px; background-color: #d1c3cd;}
TD {border-width: 1px; padding: 3px; border-style: solid; border-color: black; padding: 5px}
TD.toobig {background-color : red; color : green}
</style>
"@

# HTML Body
$Body = @"
<title>Quota Report</title>
<h1>Quota Report</h1>
<h2>Region Location: $Location</h2>
<p>The following report was run on 10/07/2019 23:02:42.</p>
"@

    # Get Azure VM Usage Quota information
    $AZVMUsage = Get-AzVMUsage -Location $Location | Select-Object @{Name = 'Name';Expression = {"$($_.Name.LocalizedValue)"}},CurrentValue,Limit,@{Name = 'PercentUsed';Expression = {"{0:P2}" -f ($_.CurrentValue / $_.Limit)}}  | sort-object  { [INT]($_.percentused -replace '%')  } -descending                        
    
    # If the percent used is above the threshold defined, color the cell red.
    $AZVMUsageHTML = $AZVMUsage | ConvertTo-Html | Set-CellColor percentused red -Filter "percentused -ge $Threshold"

    # Combine HTML elements for output
    $Header + $Body + $AZVMUsageHTML

}

# Write to the Azure Functions log stream.
Write-Host "PowerShell HTTP trigger function processed a request."

# Check if Threshold is passed.
# The threshold defines at what % of Capacity Used the HTML Cell is colored red
$Threshold = $Request.Query.Threshold
if (-not $Threshold) {
    $Threshold = $Request.Body.Threshold
}

# Check if Threshold exists.  If not, 400 HTTP code is passed back to client.
# If threshold was passed, verify the value is between 1 and 100.
# If not between 1 and 100, send 400 HTTP code back specifying the value must be between 1 and 100.
if ($Threshold)
{
    if (-not([int]$Threshold -in 1..100))
    {
        $status = [HttpStatusCode]::BadRequest
        $Body = "The Threshold value of $Threshold is not an acceptable threshold value. Please specify a number between 1 and 100 and try again."
        Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
            StatusCode = $status
            Body = $Body
        })
        exit
    }
}
else
{
    $status = [HttpStatusCode]::BadRequest
    $Body = "Please pass a threshold value between 1 and 100 on the query string or in the request body."
    Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
        StatusCode = $status
        Body = $Body
    })

}

# Check if Location is passed for the region.
# The location defines the region name that will used when checking VM Quota Usage.
$Location = $Request.Query.Location
if (-not $Location) {
    $Location = $Request.Body.Location
}

# Check if Location exists.  If not, 400 HTTP code is passed back to client.
# If location as passed, verify the region exists.  
# If location passed is not a valid Azure Region, send 400 HTTP code back spefiying the location is not a valid Azure Region.
if ($Location) {
    $CurrentAZRegions = Get-AZLocation | Select-Object Location
    if ($CurrentAZRegions.Location -contains $Location)
    {
        # If Location passed is a valid Azure Region, run the Get-AZQuotaUsageHTML function to start collecting Quota Usage.
        $HTML = Get-AZQuotaUsageHTML
        $status = [HttpStatusCode]::OK

        Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
        headers = @{'content-type' = 'text/html'}
        StatusCode = $status
        Body = $HTML
        })
    }
    else
    {
        $status = [HttpStatusCode]::BadRequest
        $Body = "$Location is not a valid Azure Region.  Please specify a valid Azure Region and try again."
        Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
            StatusCode = $status
            Body = $Body
        })
        exit
    }
}
else {
    $status = [HttpStatusCode]::BadRequest
    $Body = "Please pass a location on the query string or in the request body."
    Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
        StatusCode = $status
        Body = $Body
    })
    exit
}