[CmdletBinding()]
param(
    [ValidateSet("torch", "reservoir")]
    [string]$Trainer = "torch",
    [string]$Symbols = "",
    [int]$Limit = 0,
    [string]$Lookbacks = "",
    [string]$Units = "",
    [string]$Ridges = "",
    [string]$Architectures = "",
    [string]$HiddenSizes = "",
    [string]$Layers = "",
    [string]$Dropouts = "",
    [int]$Epochs = 0,
    [int]$Patience = 0,
    [string]$Interval = "",
    [string]$EnvFile = ""
)

$ErrorActionPreference = "Stop"

$RepoRoot = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
$RuntimeDir = Join-Path $RepoRoot "runtime"
$LogFile = Join-Path $RuntimeDir "lstm_retrain.log"
New-Item -ItemType Directory -Force -Path $RuntimeDir | Out-Null

function Write-RetrainLog {
    param([string]$Message)
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ssK"
    "[$timestamp] $Message" | Tee-Object -FilePath $LogFile -Append
}

function Resolve-Python {
    $venvPython = Join-Path $RepoRoot ".venv\Scripts\python.exe"
    if (Test-Path $venvPython) {
        return $venvPython
    }

    $userPython = Join-Path $env:LOCALAPPDATA "Programs\TradeBotPython312\python.exe"
    if (Test-Path $userPython) {
        return $userPython
    }

    foreach ($candidate in @("python.exe", "python")) {
        $command = Get-Command $candidate -ErrorAction SilentlyContinue
        if (-not $command) {
            continue
        }
        return $command.Source
    }
    throw "Python was not found. Create .venv or install Python 3.12."
}

if (-not $Symbols -and $env:LSTM_RETRAIN_SYMBOLS) { $Symbols = $env:LSTM_RETRAIN_SYMBOLS }
if ($Limit -le 0) {
    $Limit = if ($env:LSTM_RETRAIN_LIMIT) { [int]$env:LSTM_RETRAIN_LIMIT } else { 1000 }
}
if (-not $Lookbacks) { $Lookbacks = if ($env:LSTM_RETRAIN_LOOKBACKS) { $env:LSTM_RETRAIN_LOOKBACKS } else { "32,64" } }
if (-not $Units) { $Units = if ($env:LSTM_RETRAIN_UNITS) { $env:LSTM_RETRAIN_UNITS } else { "4,6" } }
if (-not $Ridges) { $Ridges = if ($env:LSTM_RETRAIN_RIDGES) { $env:LSTM_RETRAIN_RIDGES } else { "0.001" } }
if (-not $Architectures) { $Architectures = if ($env:LSTM_RETRAIN_ARCHITECTURES) { $env:LSTM_RETRAIN_ARCHITECTURES } else { "lstm,gru" } }
if (-not $HiddenSizes) { $HiddenSizes = if ($env:LSTM_RETRAIN_HIDDEN_SIZES) { $env:LSTM_RETRAIN_HIDDEN_SIZES } else { "16,32" } }
if (-not $Layers) { $Layers = if ($env:LSTM_RETRAIN_LAYERS) { $env:LSTM_RETRAIN_LAYERS } else { "1" } }
if (-not $Dropouts) { $Dropouts = if ($env:LSTM_RETRAIN_DROPOUTS) { $env:LSTM_RETRAIN_DROPOUTS } else { "0.0" } }
if ($Epochs -le 0) { $Epochs = if ($env:LSTM_RETRAIN_EPOCHS) { [int]$env:LSTM_RETRAIN_EPOCHS } else { 60 } }
if ($Patience -le 0) { $Patience = if ($env:LSTM_RETRAIN_PATIENCE) { [int]$env:LSTM_RETRAIN_PATIENCE } else { 10 } }
if (-not $Interval -and $env:LSTM_RETRAIN_INTERVAL) { $Interval = $env:LSTM_RETRAIN_INTERVAL }
if (-not $EnvFile -and $env:LSTM_RETRAIN_ENV) { $EnvFile = $env:LSTM_RETRAIN_ENV }
if (-not $EnvFile -and (Test-Path (Join-Path $RepoRoot ".env"))) { $EnvFile = Join-Path $RepoRoot ".env" }

$mutex = New-Object System.Threading.Mutex($false, "TradeBotLstmRetrainer")
$hasLock = $false
$pushedLocation = $false

try {
    $hasLock = $mutex.WaitOne(0)
    if (-not $hasLock) {
        Write-RetrainLog "Another LSTM retrain is already running; skipping."
        exit 0
    }

    $python = Resolve-Python
    if ($Trainer -eq "torch") {
        $trainerArgs = @(
            "-u",
            "tools\train_torch_recurrent_forecaster.py",
            "--limit", $Limit.ToString(),
            "--lookbacks", $Lookbacks,
            "--architectures", $Architectures,
            "--hidden-sizes", $HiddenSizes,
            "--layers", $Layers,
            "--dropouts", $Dropouts,
            "--epochs", $Epochs.ToString(),
            "--patience", $Patience.ToString()
        )
    } else {
        $trainerArgs = @(
            "-u",
            "tools\train_lstm_forecaster.py",
            "--limit", $Limit.ToString(),
            "--lookbacks", $Lookbacks,
            "--units", $Units,
            "--ridges", $Ridges
        )
    }
    if ($Symbols) { $trainerArgs += @("--symbols", $Symbols) }
    if ($Interval) { $trainerArgs += @("--interval", $Interval) }
    if ($EnvFile) { $trainerArgs += @("--env", $EnvFile) }

    Push-Location $RepoRoot
    $pushedLocation = $true
    Write-RetrainLog "Starting LSTM retrain: $python $($trainerArgs -join ' ')"
    & $python @trainerArgs 2>&1 | Tee-Object -FilePath $LogFile -Append
    if ($LASTEXITCODE -ne 0) {
        throw "Trainer failed with exit code $LASTEXITCODE."
    }
    Write-RetrainLog "Finished LSTM retrain."
}
catch {
    Write-RetrainLog "ERROR: $($_.Exception.Message)"
    exit 1
}
finally {
    if ($pushedLocation) {
        Pop-Location -ErrorAction SilentlyContinue
    }
    if ($hasLock) {
        $mutex.ReleaseMutex()
    }
    $mutex.Dispose()
}