<#
.Synopsis
    Simple folder based script execution environment.
    
.DESCRIPTION
    Simple folder based script execution environment designed for modularity.

    Suitable for the automation tasks as a better alternative to a Behemoth-class monolithic scripts.

    Script execution order is a simple alphanumeric sort by the file name.
    
.EXAMPLE
    ./start.ps1

    # execute in the current directory
    
.EXAMPLE
    ./start.ps1 -MainScriptRoot /mnt/tukayyid

    # expect everything are located at the specified path
    
.EXAMPLE
    ./start.ps1 -PSModule /data/ironhold/psmodule

    # load the PS modules form the specified path

#>
[CmdletBinding()]
param (
    # Path where the scripts and data for the execution are located
    $Root = $PSScriptRoot,

    # Configuration storage path
    $Config,

    # Data storage path
    $Data,

    # .NET assemblies directory
    $Lib,

    # PowerShell modules path (would be added to PSModulesPath for the auto-magik)
    $PSModule,

    # Custom arguments 
    [Parameter(
        ValueFromRemainingArguments=$true
        )]
    $CustomArgs

    )

# this is a global variable which would be accessbile anywhere in the session

$global:BS = @{

    Path = @{
        PSScriptRoot = $PSScriptRoot
        Root = $null
        }

    Config = @{
        }

    }

# workaround for the interactive script launch (ie no defined $Root)

if ($PSBoundParameters['Root']) {
    $global:BS.Path.Root = $PSBoundParameters['Root']
    }
else {
    $global:BS.Path.Root = $PSScriptRoot
    }

# add any custom args to the configuration var

if ($PSBoundParameters['CustomArgs']) {
    $global:BS.Config.Add('CustomArgs', $PSBoundParameters['CustomArgs'])
    }

# auto configure the main paths

# list of the variables
@(
    'config'
    'data'
    'lib'
    'psmodule'
    ) | % {

    if ($value = $PSBoundParameters[$_]) {
        
        # if this path was supplied at the start then add it as is

        $global:BS.Path.Add($_, $value)

        }
    else {

        # otherwise assume it's under the main script root path
        # no attemps are made for the path validation, it's upon you

        $global:BS.Path.Add($_, (Join-Path $BS.Path.Root $_))

        }

    }

# Adding ./psmodule to $PSModulePath allows the module auto loading without explicitly 
# calling Import-Module with the absolute or relative paths
# Note, if you prefer for the bundled modules not to be loaded before the ones available in the system,
# swap '{0}{1}{2}' to '{2}{1}{0}'

if (Test-Path $BS.Path.PSModule) {

    # if the path exists

    if ($Env:PSModulePath -match [regex]::Escape($BS.Path.PSModule)) {

        # nothing to do, the path was already in PSModulePath

        }
    else {

        $Env:PSModulePath = '{0}{1}{2}' -f $BS.Path.PSModule, [System.IO.Path]::PathSeparator, $Env:PSModulePath

        }
    }

# load any configiguration to the global variable

if (Test-Path $BS.Path.config) {

    foreach ($file in (gci $BS.Path.config -Filter *.json)) {

        try {

            $json = Get-Content $file.fullname | ConvertFrom-json

            $BS.config.add($file.basename, $json)

            }
        catch {

            write-warning ('Failed to load configuration data from the file "{0}"' -f $file.fullname)

            }

        }

    }

# auto load .NET assemblies

    function Register-Assembly {
    <#
    .Synopsis
       Load .NET assembly
    .DESCRIPTION
       Load .NET assembly or assemblies
    .EXAMPLE
       Register-Assembly

       Load any .dll in the current path
    .EXAMPLE
       Register-Assembly -Path ./lib/nestandard99/kewllib.dll

       Load a dll from the explicit path
    #>
        [CmdletBinding()]
        [Alias('Register-Assemblies')]
        Param
        (

        # Path to *.dll
        [Alias('AssemblyPath')] 
        $Path = $PWD
    
        )

        function loadassembly {
            param ($pathToDll)

                try {
                    [System.Reflection.Assembly]::LoadFile($pathToDll)
                    Write-Verbose ("Loaded assembly: {0}" -f $pathToDll)
                    }
                catch {
                    Write-Error $_
                    }
            }

    
        try {
            $thisPath = Get-Item $Path -ErrorAction Stop

            if ($thisPath.PSIsContainer) {
                Get-ChildItem -Filter '*.dll' | % {
                    loadassembly $_.FullName
                    }
                }

            # this whould be triggered both for when PSIsContainer is false (ie this is a file) and when this property doesn't exists
            else {
                loadassembly $thisPath.FullName
                }

            }
        Catch {
            Write-Error $_
            }
    

        } # end function Register-Assembly


# $PSVersionTable.PSVersion

    # Windows PowerShell 5.x
    if ($PSVersionTable.PSVersion.Major -eq 5) {
        $subFolder = 'net4'
        }

    # PowerShell 6
elseif ($PSVersionTable.PSVersion.Major -eq 6) {
        $subFolder = 'netstandard2'
        }

    # PowerShell 7.0
elseif ($PSVersionTable.PSVersion -lt [version]'7.2.0') {
        $subFolder = 'netstandard2'
        }

    # PowerShell 7.2
elseif ($PSVersionTable.PSVersion -lt [version]'7.3.0') {
        $subFolder = 'net6'
        }

    # PowerShell 7.3+
else {
        $subFolder = 'net7' 
        }

$pathToLoadFrom = Join-Path $global:BS.Path.lib $subFolder

if (Test-Path $pathToLoadFrom) {
    Write-Verbose ("Loading .NET assemblies from the path: {0}" -f $pathToLoadFrom)
    Register-Assembly -AssemblyPath $pathToLoadFrom
    }

Remove-Variable subFolder, pathToLoadFrom -ErrorAction SilentlyContinue

# end load .NET assemblies

# use only dirs named like 01-Something etc

$dirsToProcess = gci -Path $BS.Path.Root -Directory | ? Name -Match '\d+-\w+' | Sort-Object Name

foreach ($thisDir in $dirsToProcess) {
    
    $scriptFiles = gci $thisDir.FullName -Filter '*.ps1' | Sort-Object Name

    foreach ($thisFile in $scriptFiles) {

        'Processing {0}\{1}' -f $thisDir.Name, $thisFile.Name | Write-Verbose

        . $thisFile.FullName

        }
    
    }