Functions/GenXdev.Queries/Invoke-WebbrowserTabPollingScript.ps1

###############################################################################

<#
.SYNOPSIS
Executes a background polling script in a previously selected webbrowser tab.
 
.DESCRIPTION
Continuously executes JavaScript in a browser tab and processes results through
an optional callback. The script runs in a separate thread to prevent blocking.
 
.PARAMETER Scripts
JavaScript code, URLs, or file paths to execute in the browser tab.
 
.PARAMETER InitialUrl
Optional URL to navigate to before starting the polling process.
 
.PARAMETER Callback
Optional scriptblock that processes results after each poll iteration.
 
.EXAMPLE
Invoke-WebbrowserTabPollingScript -Scripts "console.log('polling')" `
    -InitialUrl "https://example.com" `
    -Callback { Write-Host "Polled" }
 
.NOTES
Requires Windows 10 or later.
#>

function Invoke-WebbrowserTabPollingScript {

    [CmdletBinding()]

    param(
        #######################################################################
        [Parameter(
            Position = 0,
            Mandatory = $false,
            HelpMessage = "JavaScript code, URLs or file paths to execute",
            ValueFromPipeline = $true,
            ValueFromPipelineByPropertyName = $true
        )]
        [Alias('FullName')]
        [object[]] $Scripts,

        #######################################################################
        [Parameter(
            Position = 1,
            Mandatory = $false,
            HelpMessage = "URL to navigate to before polling starts"
        )]
        [string] $InitialUrl,

        #######################################################################
        [Parameter(
            Position = 2,
            Mandatory = $false,
            HelpMessage = "Callback scriptblock to process poll results"
        )]
        [ScriptBlock] $Callback
        #######################################################################
    )

    begin {

        Write-Verbose "Starting browser tab polling with $(
            $Scripts.Count) scripts"


        # validate scripts parameter if provided
        if ($Scripts) {
            foreach ($script in $Scripts) {
                if ($script -isnot [string]) {
                    throw "Scripts must be strings containing JavaScript, URLs,
                        or file paths"

                }
            }
        }
    }

    process {

        # initialize thread job to run polling in background
        $job = Start-ThreadJob `
            -InitializationScript { Import-Module GenXdev.Queries } `
            -ScriptBlock {

            param ($scripts, $reference, $initialUrl, $callback)

            # initialize global state
            $global:data = @{
                urls = @()
                query = $Query
            }

            # select the target browser tab
            Select-WebbrowserTab -ByReference $reference

            # navigate to initial url if specified
            if (![string]::IsNullOrWhiteSpace($initialUrl)) {
                $null = Invoke-WebbrowserEvaluation `
                    "document.location.href='$initialUrl'" -NoAutoSelectTab
            }

            # start polling loop
            do {
                Start-Sleep -MilliSeconds 250

                # execute scripts in browser
                $null = Invoke-WebbrowserEvaluation `
                    -Scripts $scripts -NoAutoSelectTab

                # process results via callback if provided
                if ($null -ne $callback) {
                    try {
                        Invoke-Command -ScriptBlock $callback `
                            -ErrorAction SilentlyContinue
                    }
                    catch {
                        Write-Warning $PSItem.Exception
                    }

                    # reselect browser tab after callback
                    Select-WebbrowserTab -ByReference $reference
                }
            }
            while ($global:data.more)

        } -ArgumentList @(
            $Scripts,
            (Get-ChromiumSessionReference),
            $InitialUrl,
            $Callback
        )

        Write-Verbose "Started polling job with ID: $($job.Id)"
    }

    end {
    }
}