param(
    [string]$Engine = "$env:APPDATA\XianrenStudio\engines\cpu\llama-server.exe",
    [string]$Model = "$env:APPDATA\XianrenStudio\models\Qwen\Qwen2.5-0.5B-Instruct-GGUF\qwen2.5-0.5b-instruct-q4_k_m.gguf",
    [int]$Port = 8088
)

$ErrorActionPreference = "Stop"
if (-not (Test-Path $Engine)) { throw "engine not found: $Engine" }
if (-not (Test-Path $Model)) { throw "model not found: $Model" }

$log = Join-Path $env:TEMP "llama-server-smoke.log"
$args = @(
    "--model", "`"$Model`"",
    "--host", "127.0.0.1",
    "--port", "$Port",
    "--ctx-size", "2048",
    "-ngl", "0",
    "--no-webui"
)

$p = Start-Process -FilePath $Engine -ArgumentList $args `
    -RedirectStandardOutput $log -RedirectStandardError "$log.err" `
    -WindowStyle Hidden -PassThru

try {
    $ready = $false
    for ($i = 0; $i -lt 240; $i++) {
        Start-Sleep -Milliseconds 500
        try {
            $r = Invoke-RestMethod -Uri "http://127.0.0.1:$Port/health" -TimeoutSec 2
            if ($r.status -eq "ok") { $ready = $true; break }
        } catch {}
    }
    if (-not $ready) {
        Get-Content $log -ErrorAction SilentlyContinue | Select-Object -Last 20
        throw "engine did not become ready; log: $log"
    }
    Write-Host "engine ready (pid $($p.Id), port $Port)"

    $body = @{
        model      = "qwen-test"
        messages   = @(@{ role = "user"; content = "Introduce yourself in one sentence." })
        stream     = $false
        max_tokens = 128
    } | ConvertTo-Json -Depth 6
    $resp = Invoke-RestMethod -Uri "http://127.0.0.1:$Port/v1/chat/completions" `
        -Method Post -ContentType "application/json; charset=utf-8" -Body $body -TimeoutSec 120
    Write-Host "NON-STREAM REPLY: $($resp.choices[0].message.content)"

    $body2 = @{
        model    = "qwen-test"
        messages = @(@{ role = "user"; content = "Count from 1 to 5." })
        stream   = $true
        max_tokens = 64
    } | ConvertTo-Json -Depth 6
    $sse = Invoke-RestMethod -Uri "http://127.0.0.1:$Port/v1/chat/completions" `
        -Method Post -ContentType "application/json; charset=utf-8" -Body $body2 -TimeoutSec 120
    $hasDone = $sse -match "\[DONE\]"
    $dataLines = ($sse -split "`n" | Where-Object { $_ -match "^data:" }).Count
    Write-Host "STREAM: done-marker=$hasDone data-lines=$dataLines"

    if (-not $hasDone -or $dataLines -lt 2) {
        throw "streaming check failed"
    }
    Write-Host "SMOKE TEST PASSED"
} finally {
    try { Invoke-RestMethod -Method Post -Uri "http://127.0.0.1:$Port/shutdown" -TimeoutSec 5 | Out-Null } catch {}
    Start-Sleep -Seconds 1
    if (-not $p.HasExited) { Stop-Process -Id $p.Id -Force -ErrorAction SilentlyContinue }
}