"""
backend/memory/supabase_backend.py — Supabase implementation of MemoryBackend.
"""
from typing import Any, Dict, List, Optional
from .memory_backend import MemoryBackend

class SupabaseMemoryBackend(MemoryBackend):
  """
  Wrappa il client Supabase esistente in api.state per l'uso nel MemorySynchronizer.

  Il client viene risolto late-binding al momento di ogni operazione (non all'import)
  per supportare configurazioni in cui Supabase si connette dopo l'import del modulo.
  """

  def __init__(self):
      self.is_connected = self._client() is not None

  def _client(self):
      """Risolve il client Supabase corrente — None se non configurato."""
      try:
          from api.state import _sb
          return _sb
      except Exception:
          return None

  def _require_client(self):
      """Lancia RuntimeError se il client non è disponibile."""
      c = self._client()
      if c is None:
          raise RuntimeError(
              "Supabase client non disponibile: imposta SUPABASE_URL e SUPABASE_KEY "
              "nelle variabili HF Space/env prima di usare SupabaseMemoryBackend."
          )
      return c

  async def connect(self, config: Dict[str, Any]) -> None:
      """Il client è già connesso via api.state."""
      self.is_connected = self._client() is not None

  async def disconnect(self) -> None:
      """Nessuna operazione di chiusura necessaria per il client HTTP stateless."""
      self.is_connected = False

  async def add_memory(self, user_id: str, memory_data: Dict[str, Any], memory_id: Optional[str] = None) -> str:
      c    = self._require_client()
      data = {**memory_data, "user_id": user_id}
      if memory_id:
          data["id"] = memory_id
      result = c.table("memories").insert(data).execute()
      return result.data[0]["id"]

  async def get_memory(self, user_id: str, memory_id: str) -> Optional[Dict[str, Any]]:
      c      = self._require_client()
      result = c.table("memories").select("*").eq("user_id", user_id).eq("id", memory_id).execute()
      return result.data[0] if result.data else None

  async def list_memories(self, user_id: str, limit: int = 100, offset: int = 0) -> List[Dict[str, Any]]:
      c      = self._require_client()
      result = c.table("memories").select("*").eq("user_id", user_id).range(offset, offset + limit).execute()
      return result.data

  async def update_memory(self, user_id: str, memory_id: str, new_data: Dict[str, Any]) -> bool:
      c      = self._require_client()
      result = c.table("memories").update(new_data).eq("user_id", user_id).eq("id", memory_id).execute()
      return len(result.data) > 0

  async def delete_memory(self, user_id: str, memory_id: str) -> bool:
      c      = self._require_client()
      result = c.table("memories").delete().eq("user_id", user_id).eq("id", memory_id).execute()
      return len(result.data) > 0