[cmdletbinding()]
Param(
	[Parameter(
		Mandatory= $true
	)]
	[ValidateScript({Test-Path $_ -PathType Leaf})]
	[string]$Path
)

begin
{
	$system_types = @('Parameter','ValidatePattern','ValidateScript','ValidateSet')
}

process
{
	$script_path_raw = Get-Item $Path 
	$script_name = $script_path_raw.Name
	$script_path = $script_path_raw | Select-Object -ExpandProperty FullName

	$parse_errors = @()

	$AST = [System.Management.Automation.Language.Parser]::ParseFile($script_path, [ref]$null, [ref]$parse_errors)

	if($null -eq $AST.ParamBlock)
	{
		throw "No 'Param(...)' block found: $($Path)"
	}

	$parameters = @()

	foreach($param in $AST.ParamBlock.Parameters)
	{
		$param_name = $param.Name.Extent.Text
		$param_type = $null
		$param_mandatory = $false
		$param_parameters = @()
		$param_validations = @()

		foreach($attr in $param.Attributes)
		{
			if($system_types -contains $attr.TypeName.Name)
			{
				
				switch -Wildcard ($attr.TypeName.Name)
				{
					"Parameter"
					{
						foreach($named_argument in $attr.NamedArguments)
						{
							if($named_argument.ArgumentName -eq 'Mandatory')
       {
								$param_mandatory = $named_argument.Argument.Extent.Text -eq '$true'
							} else
							{

								$param_parameters += [pscustomobject]@{
									name = $named_argument.ArgumentName
									value = $named_argument.Argument.Extent.Text
								}		
							}
						}
					}
					"Validate*"
					{
						foreach($positional_argument in $attr.PositionalArguments)
						{
							if($positional_argument.ScriptBlock)
       {
								$value = $positional_argument.ScriptBlock.Extent.Text
							} else
							{
								$value = $positional_argument.Value
							}
							$param_validations += 
							[pscustomobject]@{
								name = $attr.TypeName.Name
								value = $value							
       }
						}
					}
				}
			} else
			{
				if($attr.Extent.Text -like '`[*`]')
				{
					if($param_type -ne $null)
					{
						Write-Warning "Multiple Types found for Parameter: $($attr.TypeName.Name) ($($Path))"
						continue
					}
					$param_type = $attr.TypeName.Name
				}
			}	
		}
		$parameters += [pscustomobject]@{
			name = $param_name
			type = $param_type
			mandatory = $param_mandatory
			arguments = $param_parameters
			validations = $param_validations
		}

	}
	return [pscustomobject]@{
		name = $script_name
		path = $script_path
		parameters = $parameters
	}
}