"""
FOP Worker Pool - Persistente JVM-Prozesse für schnelle PDF-Generierung.

Eliminiert JVM-Startup-Overhead durch Vorinitialisierung von N Worker-Prozessen.
Jeder Worker läuft als Daemon und verarbeitet mehrere FO→PDF Transformationen nacheinander.
"""

import logging
import subprocess
import threading
from pathlib import Path
from queue import Queue
from typing import Optional
import tempfile

logger = logging.getLogger(__name__)

# Java-Worker-Code (wird zur Laufzeit kompiliert)
FOP_WORKER_JAVA = """
import org.apache.fop.apps.*;
import org.xml.sax.SAXException;
import javax.xml.transform.*;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;
import java.io.*;
import java.net.URI;

public class FopWorker {
    public static void main(String[] args) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String line;

        System.err.println("FopWorker starting...");
        System.err.flush();

        // Create FopFactory once and reuse (major performance boost!)
        FopFactory fopFactory = null;

        try {
            // Check if config file is provided as first argument
            if (args.length > 0 && !args[0].isEmpty()) {
                File configFile = new File(args[0]);
                if (configFile.exists()) {
                    System.err.println("Loading FOP config: " + configFile.getAbsolutePath());
                    fopFactory = FopFactory.newInstance(configFile);
                } else {
                    System.err.println("Config file not found, using default configuration");
                    fopFactory = FopFactory.newInstance(new File(".").toURI());
                }
            } else {
                System.err.println("No config file specified, using default FOP configuration");
                fopFactory = FopFactory.newInstance(new File(".").toURI());
            }

            System.err.println("FopWorker started and ready");
            System.err.flush();

        } catch (Exception e) {
            System.err.println("FATAL: Failed to initialize FopFactory: " + e.getMessage());
            e.printStackTrace(System.err);
            System.exit(1);
        }

        try {
            while ((line = reader.readLine()) != null) {
                System.err.println("DEBUG: Received line: " + line.substring(0, Math.min(100, line.length())));
                System.err.flush();

                if ("EXIT".equals(line.trim())) {
                    System.err.println("FopWorker exiting");
                    break;
                }

                try {
                    // Parse job
                    System.err.println("DEBUG: Parsing job...");
                    System.err.flush();

                    String[] parts = line.split("\\t");
                    System.err.println("DEBUG: Parts count: " + parts.length);
                    System.err.flush();

                    if (parts.length < 2) {
                        System.out.println("ERROR: Invalid job format");
                        System.out.flush();
                        continue;
                    }

                    String inputFo = parts[0];
                    String outputPdf = parts[1];

                    System.err.println("DEBUG: Input FO: " + inputFo);
                    System.err.println("DEBUG: Output PDF: " + outputPdf);
                    System.err.flush();

                    // Create FOUserAgent for this transformation
                    FOUserAgent foUserAgent = fopFactory.newFOUserAgent();

                    // Note: Event Listener für detailliertes Error-Logging könnte hier hinzugefügt werden,
                    // aber ist nicht kritisch - Fehler werden durch Exceptions gefangen

                    // Create output stream
                    File outputFile = new File(outputPdf);
                    outputFile.getParentFile().mkdirs();
                    OutputStream out = new BufferedOutputStream(new FileOutputStream(outputFile));

                    try {
                        System.err.println("DEBUG: Creating Fop instance...");
                        System.err.flush();

                        // Create Fop instance
                        Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);

                        System.err.println("DEBUG: Setting up transformer...");
                        System.err.flush();

                        // Setup Transformer
                        TransformerFactory transformerFactory = TransformerFactory.newInstance();
                        Transformer transformer = transformerFactory.newTransformer();

                        // Setup input and output
                        Source src = new StreamSource(new File(inputFo));
                        Result res = new SAXResult(fop.getDefaultHandler());

                        System.err.println("DEBUG: Running FOP transformation...");
                        System.err.flush();

                        // Run transformation
                        transformer.transform(src, res);

                        System.err.println("DEBUG: FOP transformation completed");
                        System.err.flush();

                    } finally {
                        out.close();
                    }

                    // Transformation erfolgreich
                    System.out.println("OK");
                    System.out.flush();

                } catch (Exception e) {
                    System.err.println("DEBUG: Job processing exception: " + e.getClass().getName());
                    System.err.flush();
                    e.printStackTrace(System.err);

                    String errorMsg = e.getMessage();
                    if (errorMsg == null || errorMsg.isEmpty()) {
                        errorMsg = e.getClass().getSimpleName();
                    }
                    System.out.println("ERROR: " + errorMsg);
                    System.out.flush();
                }
            }
        } catch (IOException e) {
            System.err.println("FopWorker I/O error: " + e.getMessage());
            e.printStackTrace(System.err);
        }
    }
}
"""


class FopWorkerPool:
    """
    Pool von lang-laufenden JVM-Prozessen für Apache FOP PDF-Generierung.

    Eliminiert JVM-Startup-Overhead durch Wiederverwendung von N Worker-Prozessen.
    """

    def __init__(
        self,
        num_workers: int,
        java_vm_path: Path,
        apache_fop_dir: Path,
        fop_config_file: Optional[Path] = None,
        log_dir: Optional[Path] = None,
    ):
        """
        Initialisiert den FOP-Worker-Pool.

        Args:
            num_workers: Anzahl der Worker-Prozesse
            java_vm_path: Pfad zur Java VM Binary
            apache_fop_dir: Pfad zum Apache FOP-Verzeichnis
            fop_config_file: Optionaler Pfad zur fop.xconf Konfigurationsdatei
            log_dir: Optionales Verzeichnis für Worker-Logs (Standard: temp_dir/temp)
        """
        self.num_workers = num_workers
        self.java_vm_path = java_vm_path
        self.apache_fop_dir = apache_fop_dir
        self.fop_config_file = fop_config_file
        self.log_dir = log_dir

        # Worker-Prozesse und Queues
        self.workers: list[subprocess.Popen] = []
        self.job_queue: Queue = Queue()
        self.result_queue: Queue = Queue()
        self.worker_locks: list[threading.Lock] = []

        # Temporäres Verzeichnis für kompilierte Java-Klasse
        self.temp_dir: Optional[Path] = None
        self.worker_class_path: Optional[Path] = None
        self.worker_log_dir: Optional[Path] = None

        # Classpath für FOP
        self.fop_classpath: Optional[str] = None

        # Initialisierung
        self._build_fop_classpath()
        self._compile_worker_class()
        self._start_workers()

        logger.info(f"FopWorkerPool initialisiert mit {num_workers} Workern")

    def _build_fop_classpath(self):
        """Erstellt den Classpath für Apache FOP."""
        import glob
        import sys

        # Sammle alle JAR-Dateien im FOP-Verzeichnis
        all_jars = glob.glob(str(self.apache_fop_dir / "build" / "*.jar"))

        # FOP lib-Verzeichnis
        lib_dir = self.apache_fop_dir / "lib"
        if lib_dir.exists() and lib_dir.is_dir():
            all_jars.extend(glob.glob(str(lib_dir / "*.jar")))

        if not all_jars:
            raise RuntimeError(f"Keine FOP JAR-Dateien gefunden in {self.apache_fop_dir}")

        classpath_separator = ";" if sys.platform == "win32" else ":"
        self.fop_classpath = classpath_separator.join(all_jars)

        logger.debug(f"FOP Classpath: {len(all_jars)} JARs")

    def _compile_worker_class(self):
        """Kompiliert die FopWorker-Java-Klasse."""
        try:
            # Erstelle temporäres Verzeichnis
            self.temp_dir = Path(tempfile.mkdtemp(prefix="fop_worker_"))

            # Schreibe Java-Quellcode
            java_file = self.temp_dir / "FopWorker.java"
            java_file.write_text(FOP_WORKER_JAVA, encoding="utf-8")

            # Kompiliere Java-Klasse
            javac_cmd = [
                str(self.java_vm_path).replace("java", "javac"),
                "-cp",
                self.fop_classpath,
                str(java_file),
            ]

            logger.debug(f"Kompiliere FopWorker: {' '.join(javac_cmd[:3])}...")

            result = subprocess.run(javac_cmd, capture_output=True, text=True, timeout=30)

            if result.returncode != 0:
                raise RuntimeError(f"Java-Kompilierung fehlgeschlagen: {result.stderr}")

            self.worker_class_path = self.temp_dir

            logger.info(f"FopWorker erfolgreich kompiliert: {self.temp_dir}")

        except Exception as e:
            logger.error(f"Fehler beim Kompilieren von FopWorker: {e}")
            raise

    def _start_workers(self):
        """Startet N Worker-Prozesse."""
        import sys

        # Füge Worker-Classpath zum FOP-Classpath hinzu
        classpath_separator = ";" if sys.platform == "win32" else ":"
        full_classpath = str(self.worker_class_path) + classpath_separator + self.fop_classpath

        # Bestimme Log-Verzeichnis
        self.worker_log_dir = self.log_dir if self.log_dir else self.temp_dir
        if self.log_dir:
            self.worker_log_dir.mkdir(parents=True, exist_ok=True)

        for i in range(self.num_workers):
            try:
                # Starte JVM-Prozess mit FopWorker
                # Übergebe fop.xconf als Argument falls vorhanden
                cmd = [str(self.java_vm_path), "-cp", full_classpath, "FopWorker"]

                if self.fop_config_file and self.fop_config_file.exists():
                    cmd.append(str(self.fop_config_file))

                # Öffne stderr-Log-Datei für diesen Worker
                stderr_log = self.worker_log_dir / f"fop_worker_{i}_stderr.log"
                stderr_file = open(stderr_log, "w", encoding="utf-8")

                process = subprocess.Popen(
                    cmd,
                    stdin=subprocess.PIPE,
                    stdout=subprocess.PIPE,
                    stderr=stderr_file,  # Redirect stderr to file
                    text=True,
                    bufsize=1,  # Line buffered
                )

                self.workers.append(process)
                self.worker_locks.append(threading.Lock())

                logger.debug(f"FOP Worker {i} gestartet (PID: {process.pid}, stderr: {stderr_log})")

                # Warte kurz damit Worker initialisieren kann
                import time

                time.sleep(0.2)  # FOP braucht etwas länger zum Initialisieren

                # Prüfe ob Worker noch läuft
                if process.poll() is not None:
                    # Worker ist bereits beendet - Fehler!
                    stderr_file.close()
                    with open(stderr_log, "r") as f:
                        stderr_content = f.read()
                    raise RuntimeError(
                        f"FOP Worker {i} ist sofort beendet (Exit Code: {process.returncode})\nstderr:\n{stderr_content}"
                    )

            except Exception as e:
                logger.error(f"Fehler beim Starten von FOP Worker {i}: {e}")
                raise

        logger.info(f"{len(self.workers)} FOP-Worker erfolgreich gestartet")

    def build_pdf(self, input_fo: Path, output_pdf: Path) -> tuple[bool, str]:
        """
        Generiert PDF aus FO-Datei mit einem Worker aus dem Pool.

        Args:
            input_fo: Pfad zur FO-Eingabedatei
            output_pdf: Pfad zur PDF-Ausgabedatei

        Returns:
            tuple[bool, str]: (Erfolg, Fehlermeldung/Info)
        """
        # Finde freien Worker
        worker_idx = None
        for i, lock in enumerate(self.worker_locks):
            if lock.acquire(blocking=False):
                worker_idx = i
                break

        if worker_idx is None:
            # Kein freier Worker, warte auf ersten verfügbaren
            for i, lock in enumerate(self.worker_locks):
                lock.acquire()
                worker_idx = i
                break

        try:
            worker = self.workers[worker_idx]

            # Prüfe ob Worker noch läuft
            if worker.poll() is not None:
                # Worker ist tot!
                stderr_log = self.worker_log_dir / f"fop_worker_{worker_idx}_stderr.log"
                try:
                    with open(stderr_log, "r") as f:
                        stderr_content = f.read()
                    error_msg = (
                        f"FOP Worker {worker_idx} ist beendet (Exit: {worker.returncode})\nstderr:\n{stderr_content}"
                    )
                except Exception:
                    error_msg = f"FOP Worker {worker_idx} ist beendet (Exit: {worker.returncode})"
                logger.error(error_msg)
                return False, error_msg

            # Erstelle Job-String (Tab-separated)
            job = f"{input_fo}\t{output_pdf}\n"

            logger.debug(f"Sende FOP-Job an Worker {worker_idx}: {input_fo.name} → {output_pdf.name}")

            # Sende Job an Worker
            worker.stdin.write(job)
            worker.stdin.flush()

            # Warte auf Antwort
            response = worker.stdout.readline().strip()

            logger.debug(f"FOP Worker {worker_idx} Antwort: '{response}'")

            if response == "OK":
                return True, "Erfolgreich"
            elif response.startswith("ERROR:"):
                error_msg = response[6:].strip()
                return False, f"FOP-Fehler: {error_msg}"
            else:
                # Leere Antwort bedeutet Worker ist crashed
                if not response:
                    stderr_log = self.worker_log_dir / f"fop_worker_{worker_idx}_stderr.log"
                    try:
                        with open(stderr_log, "r") as f:
                            stderr_content = f.read()[-500:]  # Letzte 500 Zeichen
                        return False, f"FOP Worker {worker_idx} crashed (keine Antwort)\nstderr:\n{stderr_content}"
                    except Exception:
                        return False, f"FOP Worker {worker_idx} crashed (keine Antwort)"
                return False, f"Unerwartete Antwort: {response}"

        except Exception as e:
            logger.error(f"Fehler bei FOP Worker {worker_idx}: {e}")
            return False, f"Worker-Fehler: {str(e)}"

        finally:
            # Gebe Worker-Lock frei
            self.worker_locks[worker_idx].release()

    def shutdown(self):
        """Beendet alle Worker-Prozesse sauber."""
        logger.info("Beende FOP-Worker-Pool...")

        for i, worker in enumerate(self.workers):
            try:
                # Sende EXIT-Befehl
                if worker.stdin and not worker.stdin.closed:
                    worker.stdin.write("EXIT\n")
                    worker.stdin.flush()

                # Warte auf Beendigung (max 2 Sekunden)
                worker.wait(timeout=2)
                logger.debug(f"FOP Worker {i} beendet")

            except subprocess.TimeoutExpired:
                # Force kill falls nötig
                worker.kill()
                logger.warning(f"FOP Worker {i} musste gekillt werden")

            except Exception as e:
                logger.error(f"Fehler beim Beenden von FOP Worker {i}: {e}")

        # Lösche temporäres Verzeichnis
        if self.temp_dir and self.temp_dir.exists():
            try:
                import shutil

                shutil.rmtree(self.temp_dir)
                logger.debug(f"Temporäres Verzeichnis gelöscht: {self.temp_dir}")
            except Exception as e:
                logger.warning(f"Konnte temporäres Verzeichnis nicht löschen: {e}")

        logger.info("FOP-Worker-Pool beendet")

    def __enter__(self):
        """Context manager entry."""
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        """Context manager exit."""
        self.shutdown()