# -*- coding: utf-8 -*-
"""
Datei-basierter Event Store.

Speichert Events in Dateien für Persistenz.
"""

from __future__ import annotations

import asyncio
import json
import os
from datetime import datetime
from pathlib import Path
from typing import TYPE_CHECKING, Any

from trixy_core.events.persistence.store import (
    EventStore,
    StoredEvent,
    EventQuery,
    EventQueryResult,
)

if TYPE_CHECKING:
    from trixy_core.events.event_data.base import EventData


class FileEventStore(EventStore):
    """
    Event Store mit Datei-Persistierung.

    Speichert Events als JSON-Lines in Dateien.
    Unterstützt automatische Rotation.

    Example:
        store = FileEventStore(
            base_path="./events",
            max_file_size_mb=10,
            rotate_daily=True,
        )

        await store.append("click", event_data)

        # Events laden
        result = await store.query(EventQuery(limit=100))
    """

    def __init__(
        self,
        base_path: str | Path,
        max_file_size_mb: float = 10.0,
        rotate_daily: bool = True,
        compress_old: bool = False,
        max_files: int = 100,
    ) -> None:
        """
        Initialisiert den Store.

        Args:
            base_path: Basisverzeichnis für Events.
            max_file_size_mb: Maximale Dateigröße in MB.
            rotate_daily: Täglich neue Datei.
            compress_old: Alte Dateien komprimieren.
            max_files: Maximale Anzahl Dateien.
        """
        self._base_path = Path(base_path)
        self._max_file_size = max_file_size_mb * 1024 * 1024  # Bytes
        self._rotate_daily = rotate_daily
        self._compress_old = compress_old
        self._max_files = max_files

        self._current_file: Path | None = None
        self._current_sequence = 0
        self._lock = asyncio.Lock()

        # Verzeichnis erstellen
        self._base_path.mkdir(parents=True, exist_ok=True)

        # Letzte Sequenz ermitteln
        self._load_last_sequence()

    def _load_last_sequence(self) -> None:
        """Lädt die letzte Sequenznummer."""
        max_seq = 0
        for file_path in self._base_path.glob("events_*.jsonl"):
            try:
                with open(file_path, "r", encoding="utf-8") as f:
                    for line in f:
                        try:
                            data = json.loads(line.strip())
                            seq = data.get("sequence", 0)
                            max_seq = max(max_seq, seq)
                        except json.JSONDecodeError:
                            continue
            except IOError:
                continue

        self._current_sequence = max_seq

    def _get_current_file(self) -> Path:
        """Gibt die aktuelle Event-Datei zurück."""
        if self._rotate_daily:
            date_str = datetime.now().strftime("%Y%m%d")
            filename = f"events_{date_str}.jsonl"
        else:
            filename = "events.jsonl"

        file_path = self._base_path / filename

        # Größenprüfung
        if file_path.exists() and file_path.stat().st_size >= self._max_file_size:
            # Rotation
            counter = 1
            while True:
                rotated = self._base_path / f"{file_path.stem}_{counter}.jsonl"
                if not rotated.exists():
                    file_path.rename(rotated)
                    break
                counter += 1

        return file_path

    async def append(
        self,
        event_name: str,
        event_data: "EventData",
    ) -> StoredEvent:
        """
        Speichert ein Event.

        Args:
            event_name: Name des Events.
            event_data: Die Event-Daten.

        Returns:
            Das gespeicherte Event.
        """
        async with self._lock:
            self._current_sequence += 1
            stored = StoredEvent.from_event(
                event_name=event_name,
                event_data=event_data,
                sequence=self._current_sequence,
            )

            file_path = self._get_current_file()

            # Event als JSON-Line schreiben
            json_line = stored.to_json() + "\n"

            with open(file_path, "a", encoding="utf-8") as f:
                f.write(json_line)

            self._current_file = file_path

            # Cleanup alter Dateien
            await self._cleanup_old_files()

            return stored

    async def get(self, event_id: str) -> StoredEvent | None:
        """
        Gibt ein Event nach ID zurück.

        Args:
            event_id: Die Event-ID.

        Returns:
            StoredEvent oder None.
        """
        for file_path in sorted(self._base_path.glob("events_*.jsonl"), reverse=True):
            try:
                with open(file_path, "r", encoding="utf-8") as f:
                    for line in f:
                        try:
                            data = json.loads(line.strip())
                            if data.get("id") == event_id:
                                return StoredEvent.from_dict(data)
                        except json.JSONDecodeError:
                            continue
            except IOError:
                continue

        return None

    async def query(self, query: EventQuery) -> EventQueryResult:
        """
        Führt eine Abfrage aus.

        Args:
            query: Die Abfrage.

        Returns:
            EventQueryResult.
        """
        all_events: list[StoredEvent] = []

        # Dateien durchsuchen
        files = sorted(self._base_path.glob("events_*.jsonl"))
        if not query.order_ascending:
            files = reversed(files)

        for file_path in files:
            try:
                with open(file_path, "r", encoding="utf-8") as f:
                    for line in f:
                        try:
                            data = json.loads(line.strip())
                            event = StoredEvent.from_dict(data)

                            # Filter anwenden
                            if not self._matches_query(event, query):
                                continue

                            all_events.append(event)

                            # Früh abbrechen wenn genug
                            if len(all_events) >= query.offset + query.limit + 1:
                                break

                        except json.JSONDecodeError:
                            continue
            except IOError:
                continue

        # Sortieren
        all_events.sort(
            key=lambda e: e.sequence,
            reverse=not query.order_ascending,
        )

        total_count = len(all_events)

        # Paginierung
        start = query.offset
        end = start + query.limit
        paginated = all_events[start:end]

        return EventQueryResult(
            events=paginated,
            total_count=total_count,
            has_more=end < total_count,
            first_sequence=paginated[0].sequence if paginated else None,
            last_sequence=paginated[-1].sequence if paginated else None,
        )

    def _matches_query(self, event: StoredEvent, query: EventQuery) -> bool:
        """
        Prüft, ob ein Event zur Query passt.

        Args:
            event: Das Event.
            query: Die Query.

        Returns:
            True wenn passend.
        """
        if query.event_names and event.event_name not in query.event_names:
            return False

        if query.start_time and event.timestamp < query.start_time:
            return False

        if query.end_time and event.timestamp > query.end_time:
            return False

        if query.source and event.source != query.source:
            return False

        if query.after_sequence is not None and event.sequence <= query.after_sequence:
            return False

        if query.before_sequence is not None and event.sequence >= query.before_sequence:
            return False

        if query.metadata_filter:
            for key, value in query.metadata_filter.items():
                if event.metadata.get(key) != value:
                    return False

        return True

    async def count(self, query: EventQuery | None = None) -> int:
        """
        Zählt Events.

        Args:
            query: Optionale Abfrage.

        Returns:
            Anzahl der Events.
        """
        if query is None:
            count = 0
            for file_path in self._base_path.glob("events_*.jsonl"):
                try:
                    with open(file_path, "r", encoding="utf-8") as f:
                        count += sum(1 for _ in f)
                except IOError:
                    continue
            return count

        result = await self.query(EventQuery(
            event_names=query.event_names,
            start_time=query.start_time,
            end_time=query.end_time,
            source=query.source,
            metadata_filter=query.metadata_filter,
            limit=1000000,
        ))
        return result.total_count

    async def delete(self, event_id: str) -> bool:
        """
        Löscht ein Event.

        Args:
            event_id: Die Event-ID.

        Returns:
            True wenn gelöscht.
        """
        # Für Datei-Store nicht direkt unterstützt
        # Wäre aufwändig - besser: TTL-basiertes Cleanup
        return False

    async def clear(self) -> int:
        """
        Löscht alle Events.

        Returns:
            Anzahl gelöschter Events.
        """
        count = await self.count()

        for file_path in self._base_path.glob("events_*.jsonl"):
            try:
                file_path.unlink()
            except IOError:
                continue

        self._current_sequence = 0
        return count

    async def _cleanup_old_files(self) -> int:
        """
        Entfernt alte Dateien.

        Returns:
            Anzahl entfernter Dateien.
        """
        files = sorted(self._base_path.glob("events_*.jsonl"))

        if len(files) <= self._max_files:
            return 0

        to_remove = len(files) - self._max_files
        removed = 0

        for file_path in files[:to_remove]:
            try:
                file_path.unlink()
                removed += 1
            except IOError:
                continue

        return removed

    def get_file_stats(self) -> dict[str, Any]:
        """
        Gibt Datei-Statistiken zurück.

        Returns:
            Statistik-Dictionary.
        """
        files = list(self._base_path.glob("events_*.jsonl"))
        total_size = sum(f.stat().st_size for f in files if f.exists())

        return {
            "file_count": len(files),
            "total_size_mb": total_size / (1024 * 1024),
            "max_file_size_mb": self._max_file_size / (1024 * 1024),
            "max_files": self._max_files,
            "current_sequence": self._current_sequence,
            "files": [
                {
                    "name": f.name,
                    "size_mb": f.stat().st_size / (1024 * 1024),
                }
                for f in sorted(files)
            ],
        }