.build.ps1

[CmdletBinding()]
param
(
    [Parameter(Position = 0)]
    [System.String[]]
    $Tasks = '.',

    [Parameter()]
    [System.String]
    [ValidateScript(
        { Test-Path -Path $_ }
    )]
    $BuildConfig,

    [Parameter()]
    [System.String]
    $OutputDirectory = 'output',

    [Parameter()]
    [System.String]
    $RequiredModulesDirectory = $(Join-Path 'output' 'RequiredModules'),

    [Parameter()]
    [Alias('bootstrap')]
    [System.Management.Automation.SwitchParameter]
    $ResolveDependency,

    [Parameter(DontShow)]
    [AllowNull()]
    [System.Collections.Hashtable]
    $BuildInfo
)

<#
    The BEGIN block (at the end of this file) handles the Bootstrap of the Environment
    before Invoke-Build can run the tasks if the parameter ResolveDependency (or
    parameter alias Bootstrap) is specified.
#>

process
{

    if ($MyInvocation.ScriptName -notLike '*Invoke-Build.ps1')
    {
        # Only run the process block through InvokeBuild (look at the Begin block at the bottom of this script).
        return
    }

    # Execute the Build process from the .build.ps1 path.
    Push-Location -Path $PSScriptRoot -StackName 'BeforeBuild'

    try
    {
        Write-Host -Object "[build] Parsing defined tasks" -ForeGroundColor Magenta

        # Load the default BuildInfo if the parameter BuildInfo is not set.
        if (-not $PSBoundParameters.ContainsKey('BuildInfo'))
        {
            try
            {
                if (Test-Path -Path $BuildConfig)
                {
                    $configFile = Get-Item -Path $BuildConfig

                    Write-Host -Object "[build] Loading Configuration from $configFile"

                    $BuildInfo = switch -Regex ($configFile.Extension)
                    {
                        # Native Support for PSD1
                        '\.psd1'
                        {
                            if (-not (Get-Command -Name Import-PowerShellDataFile -ErrorAction SilentlyContinue))
                            {
                                Import-Module -Name Microsoft.PowerShell.Utility -RequiredVersion 3.1.0.0
                            }

                            Import-PowerShellDataFile -Path $BuildConfig
                        }

                        # Support for yaml when module PowerShell-Yaml is available
                        '\.[yaml|yml]'
                        {
                            Import-Module -Name 'powershell-yaml' -ErrorAction Stop

                            ConvertFrom-Yaml -Yaml (Get-Content -Raw $configFile)
                        }

                        # Native Support for JSON and JSONC (by Removing comments)
                        '\.[json|jsonc]'
                        {
                            $jsonFile = Get-Content -Raw -Path $configFile

                            $jsonContent = $jsonFile -replace '(?m)\s*//.*?$' -replace '(?ms)/\*.*?\*/'

                            # Yaml is superset of JSON.
                            ConvertFrom-Yaml -Yaml $jsonContent
                        }

                        # Unknown extension, return empty hashtable.
                        default
                        {
                            Write-Error -Message "Extension '$_' not supported. using @{}"

                            @{ }
                        }
                    }
                }
                else
                {
                    Write-Host -Object "Configuration file '$($BuildConfig.FullName)' not found" -ForegroundColor Red

                    # No config file was found, return empty hashtable.
                    $BuildInfo = @{ }
                }
            }
            catch
            {
                $logMessage = "Error loading Config '$($BuildConfig.FullName)'.`r`nAre you missing dependencies?`r`nMake sure you run './build.ps1 -ResolveDependency -tasks noop' before running build to restore the required modules."

                Write-Host -Object $logMessage -ForegroundColor Yellow

                $BuildInfo = @{ }

                Write-Error -Message $_.Exception.Message
            }
        }
        
        # If the Invoke-Build Task Header is specified in the Build Info, set it.
        if ($BuildInfo.TaskHeader)
        {
            Set-BuildHeader -Script ([scriptblock]::Create($BuildInfo.TaskHeader))
        }

        <#
            Add BuildModuleOutput to PSModule Path environment variable.
            Moved here (not in begin block) because build file can contains BuiltSubModuleDirectory value.
        #>
        if ($BuiltModuleSubdirectory)
        {
            if (-not (Split-Path -IsAbsolute -Path $BuiltModuleSubdirectory))
            {
                $BuildModuleOutput = Join-Path -Path $OutputDirectory -ChildPath $BuiltModuleSubdirectory
            }
            else
            {
                $BuildModuleOutput = $BuiltModuleSubdirectory
            }
        } # test if BuiltModuleSubDirectory set in build config file
        elseif ($BuildInfo.ContainsKey('BuiltModuleSubDirectory'))
        {
            $BuildModuleOutput = Join-Path -Path $OutputDirectory -ChildPath $BuildInfo['BuiltModuleSubdirectory']
        }
        else
        {
            $BuildModuleOutput = $OutputDirectory
        }

        # Pre-pending $BuildModuleOutput folder to PSModulePath to resolve built module from this folder.
        if ($powerShellModulePaths -notcontains $BuildModuleOutput)
        {
            Write-Host -Object "[build] Pre-pending '$BuildModuleOutput' folder to PSModulePath" -ForegroundColor Green

            $env:PSModulePath = $BuildModuleOutput + [System.IO.Path]::PathSeparator + $env:PSModulePath
        }

        <#
            Import Tasks from modules via their exported aliases when defined in Build Manifest.
            https://github.com/nightroman/Invoke-Build/tree/master/Tasks/Import#example-2-import-from-a-module-with-tasks
        #>
        if ($BuildInfo.ContainsKey('ModuleBuildTasks'))
        {
            foreach ($module in $BuildInfo['ModuleBuildTasks'].Keys)
            {
                try
                {
                    Write-Host -Object "Importing tasks from module $module" -ForegroundColor DarkGray

                    $loadedModule = Import-Module -Name $module -PassThru -ErrorAction Stop

                    foreach ($TaskToExport in $BuildInfo['ModuleBuildTasks'].($module))
                    {
                        $loadedModule.ExportedAliases.GetEnumerator().Where{
                            Write-Host -Object "`t Loading $($_.Key)..." -ForegroundColor DarkGray

                            # Using -like to support wildcard.
                            $_.Key -like $TaskToExport
                        }.ForEach{
                            # Dot-sourcing the Tasks via their exported aliases.
                           
                            . (Get-Alias $_.Key)
                        }
                    }
                }
                catch
                {
                    Write-Host -Object "Could not load tasks for module $module." -ForegroundColor Red

                    Write-Error -Message $_
                }
            }
        }

        # Loading Build Tasks defined in the .build/ folder (will override the ones imported above if same task name).
        Get-ChildItem -Path '.build/' -Recurse -Include '*.ps1' -ErrorAction Ignore |
            ForEach-Object {
                "Importing file $($_.BaseName)" | Write-Verbose

                . $_.FullName
            }

        # Synopsis: Empty task, useful to test the bootstrap process.
        task noop { }

        # Define default task sequence ("."), can be overridden in the $BuildInfo.
        task . {
            Write-Build -Object 'No sequence currently defined for the default task' -ForegroundColor Yellow
        }

        Write-Host -Object 'Adding Workflow from configuration:' -ForegroundColor DarkGray

        # Load Invoke-Build task sequences/workflows from $BuildInfo.
        foreach ($workflow in $BuildInfo.BuildWorkflow.keys)
        {
            Write-Verbose -Message "Creating Build Workflow '$Workflow' with tasks $($BuildInfo.BuildWorkflow.($Workflow) -join ', ')."

            $workflowItem = $BuildInfo.BuildWorkflow.($workflow)

            if ($workflowItem.Trim() -match '^\{(?<sb>[\w\W]*)\}$')
            {
                $workflowItem = [ScriptBlock]::Create($Matches['sb'])
            }

            Write-Host -Object "  +-> $workflow" -ForegroundColor DarkGray

            task $workflow $workflowItem
        }

        Write-Host -Object "[build] Executing requested workflow: $($Tasks -join ', ')" -ForeGroundColor Magenta

    }
    finally
    {
        Pop-Location -StackName 'BeforeBuild'
    }
}

Begin
{
    # Find build config if not specified.
    if (-not $BuildConfig)
    {
        $config = Get-ChildItem -Path "$PSScriptRoot\*" -Include 'build.y*ml', 'build.psd1', 'build.json*' -ErrorAction Ignore

        if (-not $config -or ($config -is [System.Array] -and $config.Length -le 0))
        {
            throw 'No build configuration found. Specify path via parameter BuildConfig.'
        }
        elseif ($config -is [System.Array])
        {
            if ($config.Length -gt 1)
            {
                throw 'More than one build configuration found. Specify which path to use via parameter BuildConfig.'
            }

            $BuildConfig = $config[0]
        }
        else
        {
            $BuildConfig = $config
        }
    }

    # Bootstrapping the environment before using Invoke-Build as task runner

    if ($MyInvocation.ScriptName -notlike '*Invoke-Build.ps1')
    {
        Write-Host -Object "[pre-build] Starting Build Init" -ForegroundColor Green

        Push-Location $PSScriptRoot -StackName 'BuildModule'
    }

    if ($RequiredModulesDirectory -in @('CurrentUser', 'AllUsers'))
    {
        # Installing modules instead of saving them.
        Write-Host -Object "[pre-build] Required Modules will be installed to the PowerShell module path that is used for $RequiredModulesDirectory." -ForegroundColor Green

        <#
            The variable $PSDependTarget will be used below when building the splatting
            variable before calling Resolve-Dependency.ps1, unless overridden in the
            file Resolve-Dependency.psd1.
        #>
        $PSDependTarget = $RequiredModulesDirectory
    }
    else
    {
        if (-not (Split-Path -IsAbsolute -Path $OutputDirectory))
        {
            $OutputDirectory = Join-Path -Path $PSScriptRoot -ChildPath $OutputDirectory
        }

        # Resolving the absolute path to save the required modules to.
        if (-not (Split-Path -IsAbsolute -Path $RequiredModulesDirectory))
        {
            $RequiredModulesDirectory = Join-Path -Path $PSScriptRoot -ChildPath $RequiredModulesDirectory
        }

        # Create the output/modules folder if not exists, or resolve the Absolute path otherwise.
        if (Resolve-Path -Path $RequiredModulesDirectory -ErrorAction SilentlyContinue)
        {
            Write-Debug -Message "[pre-build] Required Modules path already exist at $RequiredModulesDirectory"

            $requiredModulesPath = Convert-Path -Path $RequiredModulesDirectory
        }
        else
        {
            Write-Host -Object "[pre-build] Creating required modules directory $RequiredModulesDirectory." -ForegroundColor Green

            $requiredModulesPath = (New-Item -ItemType Directory -Force -Path $RequiredModulesDirectory).FullName
        }

        $powerShellModulePaths = $env:PSModulePath -split [System.IO.Path]::PathSeparator

        # Pre-pending $requiredModulesPath folder to PSModulePath to resolve from this folder FIRST.
        if ($RequiredModulesDirectory -notin @('CurrentUser', 'AllUsers') -and
            ($powerShellModulePaths -notcontains $RequiredModulesDirectory))
        {
            Write-Host -Object "[pre-build] Pre-pending '$RequiredModulesDirectory' folder to PSModulePath" -ForegroundColor Green

            $env:PSModulePath = $RequiredModulesDirectory + [System.IO.Path]::PathSeparator + $env:PSModulePath
        }

        $powerShellYamlModule = Get-Module -Name 'powershell-yaml' -ListAvailable
        $invokeBuildModule = Get-Module -Name 'InvokeBuild' -ListAvailable
        $psDependModule = Get-Module -Name 'PSDepend' -ListAvailable

        # Checking if the user should -ResolveDependency.
        if (-not ($powerShellYamlModule -and $invokeBuildModule -and $psDependModule) -and -not $ResolveDependency)
        {
            if ($AutoRestore -or -not $PSBoundParameters.ContainsKey('Tasks') -or $Tasks -contains 'build')
            {
                Write-Host -Object "[pre-build] Dependency missing, running './build.ps1 -ResolveDependency -Tasks noop' for you `r`n" -ForegroundColor Yellow

                $ResolveDependency = $true
            }
            else
            {
                Write-Warning -Message "Some required Modules are missing, make sure you first run with the '-ResolveDependency' parameter. Running 'build.ps1 -ResolveDependency -Tasks noop' will pull required modules without running the build task."
            }
        }

        <#
            The variable $PSDependTarget will be used below when building the splatting
            variable before calling Resolve-Dependency.ps1, unless overridden in the
            file Resolve-Dependency.psd1.
        #>
        $PSDependTarget = $requiredModulesPath
    }

    if ($ResolveDependency)
    {
        Write-Host -Object "[pre-build] Resolving dependencies." -ForegroundColor Green
        $resolveDependencyParams = @{ }

        # If BuildConfig is a Yaml file, bootstrap powershell-yaml via ResolveDependency.
        if ($BuildConfig -match '\.[yaml|yml]$')
        {
            $resolveDependencyParams.Add('WithYaml', $true)
        }

        $resolveDependencyAvailableParams = (Get-Command -Name '.\Resolve-Dependency.ps1').Parameters.Keys

        foreach ($cmdParameter in $resolveDependencyAvailableParams)
        {
            # The parameter has been explicitly used for calling the .build.ps1
            if ($MyInvocation.BoundParameters.ContainsKey($cmdParameter))
            {
                $paramValue = $MyInvocation.BoundParameters.Item($cmdParameter)

                Write-Debug " adding  $cmdParameter :: $paramValue [from user-provided parameters to Build.ps1]"

                $resolveDependencyParams.Add($cmdParameter, $paramValue)
            }
            # Use defaults parameter value from Build.ps1, if any
            else
            {
                $paramValue = Get-Variable -Name $cmdParameter -ValueOnly -ErrorAction Ignore

                if ($paramValue)
                {
                    Write-Debug " adding  $cmdParameter :: $paramValue [from default Build.ps1 variable]"

                    $resolveDependencyParams.Add($cmdParameter, $paramValue)
                }
            }
        }

        Write-Host -Object "[pre-build] Starting bootstrap process." -ForegroundColor Green

        .\Resolve-Dependency.ps1 @resolveDependencyParams
    }

    if ($MyInvocation.ScriptName -notlike '*Invoke-Build.ps1')
    {
        Write-Verbose -Message "Bootstrap completed. Handing back to InvokeBuild."

        if ($PSBoundParameters.ContainsKey('ResolveDependency'))
        {
            Write-Verbose -Message "Dependency already resolved. Removing task."

            $null = $PSBoundParameters.Remove('ResolveDependency')
        }

        Write-Host -Object "[build] Starting build with InvokeBuild." -ForegroundColor Green

        Invoke-Build @PSBoundParameters -Task $Tasks -File $MyInvocation.MyCommand.Path

        Pop-Location -StackName 'BuildModule'

        return
    }
}