"""Stop an existing instance of this application's Windows server."""

import json
import os
import subprocess
from pathlib import Path

_CONFIRM_SCRIPT = r'''
function Confirm-ServerRestart {
    Add-Type -AssemblyName System.Windows.Forms
    $answer = [System.Windows.Forms.MessageBox]::Show(
        "Es läuft bereits eine Version des Tätigkeitsnachweis-Generators.`n`nSoll das alte Programm beendet und die neue Version gestartet werden?`nDie aktuellen Auswahlen gehen dabei verloren.",
        'Tätigkeitsnachweis-Generator',
        [System.Windows.Forms.MessageBoxButtons]::YesNo,
        [System.Windows.Forms.MessageBoxIcon]::Question,
        [System.Windows.Forms.MessageBoxDefaultButton]::Button2
    )
    return $answer -eq [System.Windows.Forms.DialogResult]::Yes
}
'''


def stop_existing_server(port: int = 8501) -> bool:
    """Ask before stopping this app. Return False if the user declines."""
    if os.name != "nt":
        raise RuntimeError("Der kontrollierte Server-Neustart unterstützt nur Windows.")

    app_path = str(Path(__file__).resolve().with_name("app.py"))
    # Pass paths through the environment, never interpolate them into shell code.
    env = dict(os.environ, APP_RESTART_PATH=app_path, APP_RESTART_PID=str(os.getpid()),
               APP_RESTART_PORT=str(port),
               APP_RESTART_VENV=str(Path(app_path).parent / ".venv" / "Scripts"))
    script = _CONFIRM_SCRIPT + r'''
[Console]::OutputEncoding = [System.Text.UTF8Encoding]::new()
$ErrorActionPreference = 'Stop'
try {
$port = [int]$env:APP_RESTART_PORT
$listeners = @(Get-NetTCPConnection -State Listen -ErrorAction Stop |
    Where-Object { $_.LocalPort -eq $port })
$processIds = @($listeners | Select-Object -ExpandProperty OwningProcess -Unique)
$targets = @()
foreach ($processId in $processIds) {
    if ($processId -eq [int]$env:APP_RESTART_PID) {
        throw "Der aktuelle Prozess belegt bereits Port $port."
    }
    $process = Get-CimInstance Win32_Process -Filter "ProcessId = $processId"
    if (-not $process) { continue }
    $isExe = $process.Name -eq 'Tätigkeitsnachweis-Generator.exe'
    $command = $process.CommandLine
    $appArgument = '(?i)\bstreamlit(?:\.exe)?"?\s+run\s+"?' +
        [regex]::Escape($env:APP_RESTART_PATH) + '"?(?:\s|$)'
    $isDev = $process.Name -match '^(python(?:w)?(?:\d+(?:\.\d+)*)?(?:w)?|streamlit)\.exe$' -and
        $command -match '(?i)\bstreamlit(?:\.exe)?"?\s+run\s+' -and
        ($command -match $appArgument -or
         ($command -match '(?i)\bstreamlit(?:\.exe)?"?\s+run\s+"?app\.py"?(?:\s|$)' -and
          [IO.Path]::GetDirectoryName($process.ExecutablePath) -eq $env:APP_RESTART_VENV))
    if (-not ($isExe -or $isDev)) {
        throw "Port $port wird von einem anderen Programm verwendet (PID $processId, $($process.Name)). Bitte manuell prüfen."
    }
    $targets += $processId
}
if ($targets.Count -gt 0 -and -not (Confirm-ServerRestart)) {
    exit 2
}
foreach ($processId in $targets) {
    Stop-Process -Id $processId -Force -ErrorAction Stop
}
$deadline = (Get-Date).AddSeconds(10)
do {
    $remaining = @(Get-NetTCPConnection -State Listen -ErrorAction Stop |
        Where-Object { $_.LocalPort -eq $port })
    if ($remaining.Count -eq 0) { break }
    Start-Sleep -Milliseconds 200
} while ((Get-Date) -lt $deadline)
if ($remaining.Count -gt 0) { throw "Port $port wurde nicht rechtzeitig freigegeben." }
ConvertTo-Json -Compress -InputObject @($targets)
} catch {
    [Console]::Error.WriteLine($_.Exception.Message)
    exit 1
}
'''
    result = subprocess.run(
        ["powershell.exe", "-NoProfile", "-NonInteractive", "-Command", script],
        env=env, capture_output=True, text=True, encoding="utf-8", errors="replace",
    )
    if result.returncode == 2:
        return False
    if result.returncode:
        raise RuntimeError((result.stderr or "").strip() or "Der bestehende Server konnte nicht beendet werden.")
    stopped = json.loads(result.stdout.strip() or "[]")
    if stopped:
        print(f"[INFO] Vorherige Instanz beendet (PID: {stopped}).", flush=True)
    return True


if __name__ == "__main__":
    try:
        if not stop_existing_server():
            print("[INFO] Die bisherige Version bleibt geöffnet. Keine neue Instanz gestartet.")
            raise SystemExit(2)
    except (RuntimeError, OSError, subprocess.SubprocessError) as exc:
        print(f"[FEHLER] {exc}")
        raise SystemExit(1)