[CmdletBinding()]
param(
    [Parameter(Mandatory = $true, ValueFromPipeline = $false, ValueFromPipelineByPropertyName = $false)]
    [string]$WorkerName,

    [Parameter(Mandatory = $true, ValueFromPipeline = $false, ValueFromPipelineByPropertyName = $false)]
    [string]$WorkerType,

    [Parameter(ValueFromPipeline = $false, ValueFromPipelineByPropertyName = $false)]
    [string]$DataRoot = (Join-Path ([Environment]::GetFolderPath('LocalApplicationData')) 'UnifiedWorkers'),

    [Parameter(ValueFromPipeline = $false, ValueFromPipelineByPropertyName = $false)]
    [switch]$CommandOnly,

    [Parameter(ValueFromPipeline = $false, ValueFromPipelineByPropertyName = $false)]
    [string]$Command
)

$ErrorActionPreference = 'Continue'

# Explicitly clear any pipeline input to prevent binding errors
$null = $input

# Ensure we can see output immediately
try {
    [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
} catch {}
try {
    $Host.UI.RawUI.BufferSize = New-Object System.Management.Automation.Host.Size(200, 9999)
} catch {}

Write-Host "========================================" -ForegroundColor Cyan
Write-Host "Worker Attach Session Starting" -ForegroundColor Cyan
Write-Host "Worker: $WorkerName" -ForegroundColor White
Write-Host "Type: $WorkerType" -ForegroundColor White
Write-Host "========================================" -ForegroundColor Cyan
[Console]::Out.Flush()

# Ensure output is visible immediately
try {
    [Console]::OutputEncoding = [System.Text.Encoding]::UTF8
} catch {}
try {
    $Host.UI.RawUI.BufferSize = New-Object System.Management.Automation.Host.Size(200, 9999)
} catch {}

Write-Host "Starting attach session..." -ForegroundColor Green
Write-Host "Worker: $WorkerName, Type: $WorkerType" -ForegroundColor Gray
[Console]::Out.Flush()

function Get-WorkerPaths {
    param([string]$Root, [string]$Type, [string]$Name)

    $instanceRoot = Join-Path -Path (Join-Path -Path $Root -ChildPath $Type) -ChildPath $Name
    return [pscustomobject]@{
        Metadata = Join-Path -Path $instanceRoot -ChildPath 'state\worker-info.json'
        Command  = Join-Path -Path $instanceRoot -ChildPath 'state\commands.txt'
        Log      = Join-Path -Path $instanceRoot -ChildPath 'logs\worker.log'
    }
}

$paths = Get-WorkerPaths -Root $DataRoot -Type $WorkerType -Name $WorkerName

if (-not (Test-Path $paths.Metadata)) {
    Write-Host ""
    Write-Host "ERROR: No worker metadata found for $WorkerName ($WorkerType)." -ForegroundColor Red
    Write-Host "Metadata path: $($paths.Metadata)" -ForegroundColor Gray
    Write-Host "Data root: $DataRoot" -ForegroundColor Gray
    Write-Host ""
    Write-Host "Press any key to exit..."
    try {
        $null = $Host.UI.RawUI.ReadKey("NoEcho,IncludeKeyDown")
    } catch {
        Start-Sleep -Seconds 5
    }
    exit 1
}

try {
    $metadata = Get-Content -Path $paths.Metadata -Raw | ConvertFrom-Json
}
catch {
    Write-Host "Unable to read worker metadata: $($_.Exception.Message)" -ForegroundColor Red
    exit 1
}

if (Test-Path $paths.Log) {
    # ensure log file exists but do not truncate
    $null = (Get-Item $paths.Log)
} else {
    New-Item -Path $paths.Log -ItemType File -Force | Out-Null
}

if (-not (Test-Path $paths.Command)) {
    New-Item -Path $paths.Command -ItemType File -Force | Out-Null
}

function Send-WorkerCommand {
    param([string]$Value)

    $clean = $Value.Trim()
    if (-not $clean) {
        return
    }

    Add-Content -Path $paths.Command -Value $clean -Encoding UTF8
    Write-Host "Sent command '$clean' to $WorkerName." -ForegroundColor DarkGray
}

if ($CommandOnly) {
    if (-not $Command) {
        Write-Host "CommandOnly flag set but no command provided." -ForegroundColor Red
        exit 1
    }

    Send-WorkerCommand -Value $Command
    exit 0
}

Write-Host ""
Write-Host "========================================" -ForegroundColor Cyan
Write-Host "Attaching to $WorkerName ($WorkerType) logs." -ForegroundColor Cyan
Write-Host "Log file: $($paths.Log)" -ForegroundColor Gray
Write-Host "========================================" -ForegroundColor Cyan
[Console]::Out.Flush()
[Console]::Error.WriteLine("Attach session initialized")

# Show initial log content if available
if (Test-Path $paths.Log) {
    $initialLines = Get-Content -Path $paths.Log -Tail 50 -ErrorAction SilentlyContinue
    if ($initialLines) {
        Write-Host "--- Recent log output ---" -ForegroundColor DarkGray
        $initialLines | ForEach-Object { Write-Host $_ }
        Write-Host "--- End of initial output ---" -ForegroundColor DarkGray
    } else {
        Write-Host "Log file exists but is empty. Waiting for worker output..." -ForegroundColor Yellow
    }
} else {
    Write-Host "Log file does not exist yet. Waiting for worker to start..." -ForegroundColor Yellow
}

Write-Host ""
Write-Host "Type commands and press Enter. Type 'detach' to exit session." -ForegroundColor Yellow
Write-Host ""

# Use Register-ObjectEvent for file system watcher, or simpler: just tail in background and poll
$logJob = Start-Job -ScriptBlock {
    param($LogPath)
    if (Test-Path $LogPath) {
        Get-Content -Path $LogPath -Tail 0 -Wait -ErrorAction SilentlyContinue
    } else {
        while (-not (Test-Path $LogPath)) {
            Start-Sleep -Milliseconds 500
        }
        Get-Content -Path $LogPath -Tail 0 -Wait -ErrorAction SilentlyContinue
    }
} -ArgumentList $paths.Log

try {
    while ($true) {
        # Check for new log output from background job (non-blocking)
        $logOutput = Receive-Job -Job $logJob -ErrorAction SilentlyContinue
        if ($logOutput) {
            $logOutput | ForEach-Object { Write-Host $_ }
            [Console]::Out.Flush()
        }

        # Use a timeout on Read-Host to allow periodic log checking
        # Since Read-Host doesn't support timeout, we'll just check logs before each Read-Host
        # This means logs will be checked whenever user presses Enter
        
        $input = Read-Host "> "
        if ($null -eq $input) {
            continue
        }

        $normalized = $input.Trim()
        if ($normalized.StartsWith(':')) {
            $normalized = $normalized.TrimStart(':').Trim()
        }

        if ($normalized.Length -eq 0) {
            continue
        }

        if ($normalized.ToLowerInvariant() -eq 'detach') {
            break
        }

        Send-WorkerCommand -Value $input
    }
}
catch {
    Write-Host "Error in attach session: $($_.Exception.Message)" -ForegroundColor Red
    Write-Host $_.ScriptStackTrace -ForegroundColor DarkRed
    [Console]::Error.WriteLine("Attach error: $($_.Exception.Message)")
}
finally {
    if ($logJob) {
        Stop-Job -Job $logJob -ErrorAction SilentlyContinue
        Remove-Job -Job $logJob -ErrorAction SilentlyContinue
    }

    Write-Host "Detached from worker $WorkerName." -ForegroundColor Cyan
}