param 
(
[Parameter(Mandatory=$true)][string]$osmFile,
[Parameter(Mandatory=$true)][string]$minLatitude ,
[Parameter(Mandatory=$true)][string]$minLongitude ,
[Parameter(Mandatory=$true)][string]$maxLatitude,
[Parameter(Mandatory=$true)][string]$maxLongitude 
)

function RemoveContourGlitches () {
    ForEach ($Way in $osmContent.osm.way) {
        $nodesinWay = $way.SelectNodes("./nd")
        $count = $nodesinWay.Count
        
        if ($count -lt 10) {
            RemoveReferencedNodes
            $Way.ParentNode.RemoveChild($Way)    # remove this way   
        }
    }
}

function RemoveWay ([string]$elevationValueToRemove)
{
	ForEach($Tag in $osmContent.osm.way.tag)	
    {	
        $key=$Tag.GetAttribute("k")
        $value=$Tag.GetAttribute("v")
		if($key.Equals("ele") -and $value.Equals($elevationValueToRemove)) 
        {
            $Way = $Tag.ParentNode
		    Write-Host "removed way " $Way.id " with elevation = " $elevationValueToRemove
            RemoveReferencedNodes
            $Way.ParentNode.RemoveChild($Way)    # remove this way              
		}
	}
}

function RemoveReferencedNodes  {
            $nd = $Way.FirstChild             # for each node referenced in this way
            while (!($nd -eq $null )) 
            {               
                $ref = $nd.GetAttribute("ref")
                $node=($osmContent.osm.node|where{$_.id -eq "$ref"})
                if (!($node -eq $null)) 
                {
                    $Node.ParentNode.RemoveChild($Node)
                }                
                $nd = $nd.get_nextsibling()      
            }
}

function AddZoneBoundaryTag ( [string]$elevation, [string]$newKey, [string]$newValue)
{
	ForEach($Tag in $osmContent.osm.way.tag)	
    {	
        $key =$Tag.GetAttribute("k")
        $value=$Tag.GetAttribute("v")
		if($key.Equals("ele") -and $value.Equals($elevation)) 
        {
            $AddTag = $osmContent.CreateElement("tag")
            $newKeyAttr = $osmContent.CreateAttribute("k")
            $newKeyAttr.Value = "$newKey"
            $AddTag.Attributes.Append($newKeyAttr)
            $newValueAttr = $osmContent.CreateAttribute("v")
            $newValueAttr.Value = "$newValue"
            $AddTag.Attributes.Append($newValueAttr)
            $Way = $Tag.ParentNode
            $Way.AppendChild($AddTag)       
		}
	}
}

function AddBoundaryBox () {
    $newWay = @($osmContent.osm.way)[-1].Clone()  
    $newWay.id = ([int64]($newWay.id) - 1).ToString()
    
    $todelete = $newWay.FirstChild;
    while (!($todelete -eq $null))
    {
        $newWay.RemoveChild($toDelete);
        $todelete = $newWay.FirstChild;
    }
    $newNode = @($osmContent.osm.node)[-1].Clone()  
    AddNode $MinLongitude $MinLatitude
    AddNd
    $newNode = @($osmContent.osm.node)[-1].Clone()  
    AddNode $MaxLongitude $MinLatitude
    AddNd
    $newNode = @($osmContent.osm.node)[-1].Clone()  
    AddNode $MaxLongitude $MaxLatitude
    AddNd
    $newNode = @($osmContent.osm.node)[-1].Clone()  
    AddNode $MinLongitude $MaxLatitude
    AddNd
    $newNode = @($osmContent.osm.node)[-1].Clone()  
    AddNode $MinLongitude $MinLatitude
    AddNd

    $newTag = $osmContent.CreateElement("tag")
    $newKeyAttr = $osmContent.CreateAttribute("k")
    $newKeyAttr.Value = "boundary"
    $newTag.Attributes.Append($newKeyAttr)
    $newValueAttr = $osmContent.CreateAttribute("v")
    $newValueAttr.Value = "box"
    $newTag.Attributes.Append($newValueAttr)
    $newWay.AppendChild($newTag)
    $osmContent.osm.AppendChild($newWay)

}
function AddNode ([string] $lon, [string] $lat) {
    $newNode.id = ([int64]($newNode.id) - 1).ToString()
    $newNode.lat=$lat
    $newNode.lon=$lon
    $osmcontent.osm.AppendChild($newNode)
}
function AddNd() {
    $newNd = @($osmContent.osm.way.nd)[-1].Clone()  
    $id = $newNode.id
    $newNd.ref="$id"
    $newWay.AppendChild($newNd)
}



#-----------------------------------------------------------------------
#  main
#-----------------------------------------------------------------------

#Get-ChildItem Env:

$srtmCache = $Env:srtm2osmRoot + "\SrtmCache" 
$bounds =  "-bounds1 " + "$minLatitude" + " " + "$minLongitude" + " " + "$maxLatitude" + " " + "$maxLongitude" 
$arguments = $bounds + " -step 500 -large -o " + $osmFile + " -d " + $srtmCache
$run_srtm2osm = $Env:srtm2osmRoot + "\srtm2osm\Srtm2OSM.exe "
Start-Process -FilePath "$run_srtm2osm" -ArgumentList "$arguments" -Wait -PassThru

[xml]$osmContent = Get-Content $osmFile -Encoding UTF8

RemoveWay "0"
AddZoneBoundaryTag "500" "natural" "peak"
AddZoneBoundaryTag "500" "height" "MidFoothills"
AddZoneBoundaryTag "1000" "natural" "peak"
AddZoneBoundaryTag "1000" "height" "LowerMontane"
AddZoneBoundaryTag "1500" "natural" "peak"
AddZoneBoundaryTag "1500" "height" "MidMontane"
AddZoneBoundaryTag "2000" "natural" "peak"
AddZoneBoundaryTag "2000" "height" "SubAlpine"
RemoveWay "2500"
RemoveWay "3000"
RemoveWay "3500"
RemoveWay "4000"
RemoveContourGlitches
AddBoundaryBox


$osmContent.Save($osmFile)