# -*- coding: utf-8 -*-
"""
Kompressor-Registry.

Zentrale Verwaltung von Komprimierungsalgorithmen.
"""

from __future__ import annotations

from typing import Type

from trixy_core.network.compression.compressor import (
    Compressor,
    CompressionLevel,
)
from trixy_core.network.compression.zlib import ZlibCompressor, GzipCompressor


class CompressionRegistry:
    """
    Registry für Komprimierungsalgorithmen.

    Verwaltet verfügbare Kompressoren und ermöglicht
    die Auswahl basierend auf Namen oder Content-Type.

    Beispiel:
        registry = get_default_registry()

        # Nach Namen
        compressor = registry.get("zlib")

        # Nach Content-Type
        compressor = registry.get_by_content_type("application/gzip")
    """

    def __init__(self) -> None:
        """Initialisiert die Registry."""
        self._compressors: dict[str, Type[Compressor]] = {}
        self._content_types: dict[str, str] = {}

    def register(
        self,
        name: str,
        compressor_class: Type[Compressor],
        content_type: str | None = None,
    ) -> None:
        """
        Registriert einen Kompressor.

        Args:
            name: Name des Kompressors
            compressor_class: Kompressor-Klasse
            content_type: Optional: Content-Type Mapping
        """
        self._compressors[name.lower()] = compressor_class

        if content_type:
            self._content_types[content_type.lower()] = name.lower()

    def unregister(self, name: str) -> bool:
        """
        Entfernt einen Kompressor.

        Args:
            name: Name des Kompressors

        Returns:
            True wenn entfernt
        """
        name = name.lower()
        if name in self._compressors:
            del self._compressors[name]
            # Content-Type Mapping entfernen
            to_remove = [
                ct for ct, n in self._content_types.items()
                if n == name
            ]
            for ct in to_remove:
                del self._content_types[ct]
            return True
        return False

    def get(
        self,
        name: str,
        level: CompressionLevel = CompressionLevel.DEFAULT,
    ) -> Compressor | None:
        """
        Holt Kompressor nach Namen.

        Args:
            name: Name des Kompressors
            level: Komprimierungsstufe

        Returns:
            Kompressor-Instanz oder None
        """
        compressor_class = self._compressors.get(name.lower())
        if compressor_class:
            return compressor_class(level=level)
        return None

    def get_by_content_type(
        self,
        content_type: str,
        level: CompressionLevel = CompressionLevel.DEFAULT,
    ) -> Compressor | None:
        """
        Holt Kompressor nach Content-Type.

        Args:
            content_type: Content-Type (z.B. "application/gzip")
            level: Komprimierungsstufe

        Returns:
            Kompressor-Instanz oder None
        """
        name = self._content_types.get(content_type.lower())
        if name:
            return self.get(name, level)
        return None

    def list_available(self) -> list[str]:
        """Listet alle verfügbaren Kompressoren."""
        return list(self._compressors.keys())

    def is_available(self, name: str) -> bool:
        """Prüft ob Kompressor verfügbar ist."""
        return name.lower() in self._compressors

    def __contains__(self, name: str) -> bool:
        return self.is_available(name)

    def __len__(self) -> int:
        return len(self._compressors)


# Globale Default-Registry
_default_registry: CompressionRegistry | None = None


def get_default_registry() -> CompressionRegistry:
    """
    Holt die globale Standard-Registry.

    Enthält vorregistrierte Standard-Kompressoren.

    Returns:
        CompressionRegistry-Instanz
    """
    global _default_registry

    if _default_registry is None:
        _default_registry = CompressionRegistry()

        # Zlib registrieren (immer verfügbar)
        _default_registry.register(
            "zlib",
            ZlibCompressor,
            "application/zlib"
        )

        # Gzip registrieren
        _default_registry.register(
            "gzip",
            GzipCompressor,
            "application/gzip"
        )

        # Content-Type Aliase
        _default_registry._content_types["application/x-gzip"] = "gzip"
        _default_registry._content_types["application/deflate"] = "zlib"

        # LZ4 wenn verfügbar
        try:
            from trixy_core.network.compression.lz4 import (
                LZ4Compressor,
                LZ4HCCompressor,
            )
            _default_registry.register(
                "lz4",
                LZ4Compressor,
                "application/x-lz4"
            )
            _default_registry.register(
                "lz4hc",
                LZ4HCCompressor,
                "application/x-lz4hc"
            )
        except ImportError:
            pass

    return _default_registry


def get_compressor(
    name: str,
    level: CompressionLevel = CompressionLevel.DEFAULT,
) -> Compressor | None:
    """
    Convenience-Funktion zum Holen eines Kompressors.

    Args:
        name: Name des Kompressors
        level: Komprimierungsstufe

    Returns:
        Kompressor-Instanz oder None
    """
    return get_default_registry().get(name, level)