<#
.SYNOPSIS
    Manage the langgraph dev server on Windows.
.DESCRIPTION
    Start, stop, or check the status of the langgraph dev server.
    The server starts from the skill root (where langgraph.json lives) so the
    graph module is discovered correctly.
.PARAMETER Command
    start | stop | status
.EXAMPLE
    manage_dev_server.ps1 start    # idempotent — safe to call if already running
    manage_dev_server.ps1 stop     # call once workflow returns {"status":"done"}
    manage_dev_server.ps1 status   # print running/stopped + Studio URL
#>
param([string]$Command = "status")

$SkillDir   = (Resolve-Path (Join-Path $PSScriptRoot "..")).Path
$PidFile    = Join-Path $env:TEMP "langgraph_dev_server.pid"
$StdoutLog  = Join-Path $env:TEMP "langgraph_dev_server.stdout.log"
$StderrLog  = Join-Path $env:TEMP "langgraph_dev_server.stderr.log"
$ApiUrl     = "http://127.0.0.1:2024"
$MaxWait    = 45  # seconds to wait for the server to become ready

# --- helpers -----------------------------------------------------------

function Test-HttpOk([string]$Url) {
    try {
        $r = Invoke-WebRequest -Uri $Url -UseBasicParsing -TimeoutSec 3 -ErrorAction Stop
        return ($r.StatusCode -ge 200 -and $r.StatusCode -lt 300)
    } catch {
        return $false
    }
}

function Get-StoredPid {
    if (-not (Test-Path $PidFile)) { return 0 }
    $raw = (Get-Content $PidFile -Raw -ErrorAction SilentlyContinue).Trim()
    if (-not $raw) { return 0 }
    [int]$raw
}

function Test-ServerRunning {
    $pid = Get-StoredPid
    if ($pid -eq 0) { return $false }
    $proc = Get-Process -Id $pid -ErrorAction SilentlyContinue
    if (-not $proc) { return $false }
    return (Test-HttpOk "$ApiUrl/ok")
}

function Find-LangGraphExe {
    $up = $env:USERPROFILE
    $candidates = @(
        "$up\.conda\envs\langgraph\Scripts\langgraph.exe",
        "$up\miniconda3\envs\langgraph\Scripts\langgraph.exe",
        "$up\anaconda3\envs\langgraph\Scripts\langgraph.exe",
        "$up\miniforge3\envs\langgraph\Scripts\langgraph.exe",
        "$up\AppData\Local\miniconda3\envs\langgraph\Scripts\langgraph.exe",
        "C:\ProgramData\miniconda3\envs\langgraph\Scripts\langgraph.exe",
        "C:\ProgramData\anaconda3\envs\langgraph\Scripts\langgraph.exe"
    )
    foreach ($c in $candidates) {
        if (Test-Path $c) { return $c }
    }
    # Try PATH
    $cmd = Get-Command langgraph -ErrorAction SilentlyContinue
    if ($cmd) { return $cmd.Source }
    # Try resolving via conda
    $condaCandidates = @($env:CONDA_EXE, "C:\ProgramData\miniconda3\Scripts\conda.exe",
        "$up\AppData\Local\miniconda3\Scripts\conda.exe")
    foreach ($conda in $condaCandidates) {
        if ($conda -and (Test-Path $conda)) {
            try {
                $lgPath = (& $conda run -n langgraph python -c "import shutil; print(shutil.which('langgraph') or '')" 2>$null).Trim()
                if ($lgPath -and (Test-Path $lgPath)) { return $lgPath }
            } catch {}
        }
    }
    throw ("Cannot find langgraph.exe in the 'langgraph' conda env. " +
           "Install it: conda run -n langgraph pip install 'langgraph-cli[inmem]'")
}

function Stop-ServerProcess([int]$PidValue) {
    $stopped = $false
    if ($PidValue -gt 0) {
        $proc = Get-Process -Id $PidValue -ErrorAction SilentlyContinue
        if ($proc) {
            Stop-Process -Id $PidValue -Force -ErrorAction SilentlyContinue
            $stopped = $true
        }
    }
    # Fallback: kill whoever is listening on port 2024
    if (-not $stopped) {
        $conn = Get-NetTCPConnection -LocalPort 2024 -State Listen -ErrorAction SilentlyContinue |
                Select-Object -First 1
        if ($conn) {
            Stop-Process -Id $conn.OwningProcess -Force -ErrorAction SilentlyContinue
            Write-Host "[dev-server] Stopped process on port 2024 (PID $($conn.OwningProcess))"
            $stopped = $true
        }
    }
    return $stopped
}

# --- command dispatch ---------------------------------------------------

switch ($Command) {

    "start" {
        if (Test-ServerRunning) {
            $pid = Get-StoredPid
            Write-Host "[dev-server] Already running (PID $pid) at $ApiUrl"
            Write-Host "[dev-server] Studio: https://smith.langchain.com/studio/?baseUrl=$ApiUrl"
            exit 0
        }

        $lgExe = Find-LangGraphExe
        Write-Host "[dev-server] Starting langgraph dev server..."
        Write-Host "[dev-server]   exe: $lgExe"
        Write-Host "[dev-server]   dir: $SkillDir"

        # Remove stale logs
        Remove-Item $StdoutLog -ErrorAction SilentlyContinue
        Remove-Item $StderrLog -ErrorAction SilentlyContinue

        $proc = Start-Process -FilePath $lgExe `
            -ArgumentList "dev", "--no-browser" `
            -WorkingDirectory $SkillDir `
            -RedirectStandardOutput $StdoutLog `
            -RedirectStandardError  $StderrLog `
            -WindowStyle Hidden -PassThru

        if (-not $proc) {
            Write-Error "[dev-server] Failed to launch process"
            exit 1
        }
        $proc.Id | Out-File -FilePath $PidFile -Encoding ascii -NoNewline

        # Wait for server to respond
        $elapsed = 0
        while (-not (Test-HttpOk "$ApiUrl/ok") -and $elapsed -lt $MaxWait) {
            Start-Sleep -Seconds 1
            $elapsed++
            if ($proc.HasExited) {
                Write-Error "[dev-server] Process exited unexpectedly (code $($proc.ExitCode))"
                Write-Host "--- stdout ($StdoutLog) ---"
                if (Test-Path $StdoutLog) { Get-Content $StdoutLog -Tail 30 }
                Write-Host "--- stderr ($StderrLog) ---"
                if (Test-Path $StderrLog) { Get-Content $StderrLog -Tail 30 }
                Remove-Item $PidFile -ErrorAction SilentlyContinue
                exit 1
            }
        }

        if ($elapsed -ge $MaxWait) {
            Write-Error "[dev-server] Server did not become ready within ${MaxWait}s"
            Write-Host "--- stdout ($StdoutLog) ---"
            if (Test-Path $StdoutLog) { Get-Content $StdoutLog -Tail 30 }
            Write-Host "--- stderr ($StderrLog) ---"
            if (Test-Path $StderrLog) { Get-Content $StderrLog -Tail 30 }
            exit 1
        }

        Write-Host "[dev-server] Ready in ${elapsed}s"
        Write-Host "[dev-server] API:    $ApiUrl"
        Write-Host "[dev-server] Studio: https://smith.langchain.com/studio/?baseUrl=$ApiUrl"
        Write-Host "[dev-server] Logs:   $StdoutLog  /  $StderrLog"
    }

    "stop" {
        $pid = Get-StoredPid
        if ((Stop-ServerProcess -PidValue $pid)) {
            Write-Host "[dev-server] Stopped (PID $pid)"
        } else {
            Write-Host "[dev-server] Not running (nothing to stop)"
        }
        Remove-Item $PidFile -ErrorAction SilentlyContinue
    }

    "status" {
        if (Test-ServerRunning) {
            $pid = Get-StoredPid
            Write-Host "[dev-server] Running (PID $pid) at $ApiUrl"
            Write-Host "[dev-server] Studio: https://smith.langchain.com/studio/?baseUrl=$ApiUrl"
        } else {
            Write-Host "[dev-server] Not running"
        }
    }

    default {
        Write-Error "Usage: manage_dev_server.ps1 {start|stop|status}"
        exit 1
    }
}