import logging
from datetime import datetime
from google.cloud import firestore

from ..config import Settings
from ..models import ConversationSessionDTO, ConversationEntryDTO
from ..models.notification import Notification


logger = logging.getLogger(__name__)


class FirestoreService:
    """Service for Firestore operations on conversations."""

    def __init__(self, settings: Settings):
        """Initialize Firestore client."""
        self.settings = settings
        self.db = firestore.AsyncClient(
            project=settings.gcp_project_id,
            database=settings.firestore_database_id,
        )
        self.conversations_collection = (
            f"artifacts/{settings.gcp_project_id}/conversations"
        )
        self.entries_subcollection = "mensajes"
        self.notifications_collection = (
            f"artifacts/{settings.gcp_project_id}/notifications"
        )
        logger.info(
            f"Firestore client initialized for project: {settings.gcp_project_id}"
        )

    async def close(self):
        """Close Firestore client."""
        self.db.close()
        logger.info("Firestore client closed")

    def _session_ref(self, session_id: str):
        """Get Firestore document reference for session."""
        return self.db.collection(self.conversations_collection).document(session_id)

    async def get_session(self, session_id: str) -> ConversationSessionDTO | None:
        """Retrieve conversation session from Firestore by session ID."""
        try:
            doc_ref = self._session_ref(session_id)
            doc = await doc_ref.get()

            if not doc.exists:
                logger.debug(f"Session not found in Firestore: {session_id}")
                return None

            data = doc.to_dict()
            session = ConversationSessionDTO.model_validate(data)
            logger.debug(f"Retrieved session from Firestore: {session_id}")
            return session

        except Exception as e:
            logger.error(
                f"Error retrieving session {session_id} from Firestore: {str(e)}"
            )
            return None

    async def get_session_by_phone(
        self, telefono: str
    ) -> ConversationSessionDTO | None:
        """
        Retrieve most recent conversation session from Firestore by phone number.

        Args:
            telefono: User phone number

        Returns:
            Most recent session for this phone, or None if not found
        """
        try:
            query = (
                self.db.collection(self.conversations_collection)
                .where("telefono", "==", telefono)
                .order_by("lastModified", direction=firestore.Query.DESCENDING)
                .limit(1)
            )

            docs = query.stream()
            async for doc in docs:
                data = doc.to_dict()
                session = ConversationSessionDTO.model_validate(data)
                logger.debug(
                    f"Retrieved session from Firestore for phone {telefono}: {session.sessionId}"
                )
                return session

            logger.debug(f"No session found in Firestore for phone: {telefono}")
            return None

        except Exception as e:
            logger.error(
                f"Error querying session by phone {telefono} from Firestore: {str(e)}"
            )
            return None

    async def save_session(self, session: ConversationSessionDTO) -> bool:
        """Save conversation session to Firestore."""
        try:
            doc_ref = self._session_ref(session.sessionId)
            data = session.model_dump()
            await doc_ref.set(data, merge=True)
            logger.debug(f"Saved session to Firestore: {session.sessionId}")
            return True

        except Exception as e:
            logger.error(
                f"Error saving session {session.sessionId} to Firestore: {str(e)}"
            )
            return False

    async def create_session(
        self,
        session_id: str,
        user_id: str,
        telefono: str,
        pantalla_contexto: str | None = None,
        last_message: str | None = None,
    ) -> ConversationSessionDTO:
        """Create and save a new conversation session to Firestore.

        Args:
            session_id: Unique session identifier
            user_id: User identifier
            telefono: User phone number
            pantalla_contexto: Optional screen context for the conversation
            last_message: Optional last message in the conversation

        Returns:
            The created session

        Raises:
            Exception: If session creation or save fails
        """
        session = ConversationSessionDTO.create(
            session_id=session_id,
            user_id=user_id,
            telefono=telefono,
            pantalla_contexto=pantalla_contexto,
            last_message=last_message,
        )

        doc_ref = self._session_ref(session.sessionId)
        data = session.model_dump()
        await doc_ref.set(data, merge=True)

        logger.info(f"Created new session in Firestore: {session_id}")
        return session

    async def save_entry(self, session_id: str, entry: ConversationEntryDTO) -> bool:
        """Save conversation entry to Firestore subcollection."""
        try:
            doc_ref = self._session_ref(session_id)
            entries_ref = doc_ref.collection(self.entries_subcollection)

            # Use timestamp as document ID for chronological ordering
            entry_id = entry.timestamp.isoformat()
            entry_doc = entries_ref.document(entry_id)

            data = entry.model_dump()
            await entry_doc.set(data)
            logger.debug(f"Saved entry to Firestore for session: {session_id}")
            return True

        except Exception as e:
            logger.error(
                f"Error saving entry for session {session_id} to Firestore: {str(e)}"
            )
            return False

    async def get_entries(
        self, session_id: str, limit: int = 10
    ) -> list[ConversationEntryDTO]:
        """Retrieve recent conversation entries from Firestore."""
        try:
            doc_ref = self._session_ref(session_id)
            entries_ref = doc_ref.collection(self.entries_subcollection)

            # Get entries ordered by timestamp descending
            query = entries_ref.order_by(
                "timestamp", direction=firestore.Query.DESCENDING
            ).limit(limit)

            docs = query.stream()
            entries = []

            async for doc in docs:
                entry_data = doc.to_dict()
                entry = ConversationEntryDTO.model_validate(entry_data)
                entries.append(entry)

            # Reverse to get chronological order
            entries.reverse()
            logger.debug(f"Retrieved {len(entries)} entries for session: {session_id}")
            return entries

        except Exception as e:
            logger.error(
                f"Error retrieving entries for session {session_id} from Firestore: {str(e)}"
            )
            return []

    async def delete_session(self, session_id: str) -> bool:
        """Delete conversation session and all entries from Firestore."""
        try:
            doc_ref = self._session_ref(session_id)

            # Delete all entries first
            entries_ref = doc_ref.collection(self.entries_subcollection)
            async for doc in entries_ref.stream():
                await doc.reference.delete()

            # Delete session document
            await doc_ref.delete()
            logger.debug(f"Deleted session from Firestore: {session_id}")
            return True

        except Exception as e:
            logger.error(
                f"Error deleting session {session_id} from Firestore: {str(e)}"
            )
            return False

    async def update_pantalla_contexto(
        self, session_id: str, pantalla_contexto: str | None
    ) -> bool:
        """Update the pantallaContexto field for a conversation session.

        Args:
            session_id: Session ID to update
            pantalla_contexto: New pantalla contexto value

        Returns:
            True if update was successful, False otherwise
        """
        try:
            doc_ref = self._session_ref(session_id)
            doc = await doc_ref.get()

            if not doc.exists:
                logger.warning(
                    f"Session {session_id} not found in Firestore. Cannot update pantallaContexto"
                )
                return False

            await doc_ref.update(
                {
                    "pantallaContexto": pantalla_contexto,
                    "lastModified": datetime.now(),
                }
            )

            logger.debug(
                f"Updated pantallaContexto for session {session_id} in Firestore"
            )
            return True

        except Exception as e:
            logger.error(
                f"Error updating pantallaContexto for session {session_id} in Firestore: {str(e)}"
            )
            return False

    # ====== Notification Methods ======

    def _notification_ref(self, notification_id: str):
        """Get Firestore document reference for notification."""
        return self.db.collection(self.notifications_collection).document(
            notification_id
        )

    async def save_or_append_notification(self, new_entry: Notification) -> None:
        """
        Save or append notification entry to Firestore.

        Args:
            new_entry: Notification entry to save

        Raises:
            ValueError: If phone number is missing
        """
        phone_number = new_entry.telefono
        if not phone_number or not phone_number.strip():
            raise ValueError("Phone number is required to manage notification entries")

        # Use phone number as document ID
        notification_session_id = phone_number

        try:
            doc_ref = self._notification_ref(notification_session_id)
            doc = await doc_ref.get()

            entry_dict = new_entry.model_dump()

            if doc.exists:
                # Append to existing session
                await doc_ref.update(
                    {
                        "notificaciones": firestore.ArrayUnion([entry_dict]),
                        "ultimaActualizacion": datetime.now(),
                    }
                )
                logger.info(
                    f"Successfully appended notification entry to session {notification_session_id} in Firestore"
                )
            else:
                # Create new notification session
                new_session_data = {
                    "sessionId": notification_session_id,
                    "telefono": phone_number,
                    "fechaCreacion": datetime.now(),
                    "ultimaActualizacion": datetime.now(),
                    "notificaciones": [entry_dict],
                }
                await doc_ref.set(new_session_data)
                logger.info(
                    f"Successfully created new notification session {notification_session_id} in Firestore"
                )

        except Exception as e:
            logger.error(
                f"Error saving notification to Firestore for phone {phone_number}: {str(e)}",
                exc_info=True,
            )
            raise

    async def update_notification_status(self, session_id: str, status: str) -> None:
        """
        Update the status of all notifications in a session.

        Args:
            session_id: Notification session ID (phone number)
            status: New status value
        """
        try:
            doc_ref = self._notification_ref(session_id)
            doc = await doc_ref.get()

            if not doc.exists:
                logger.warning(
                    f"Notification session {session_id} not found in Firestore. Cannot update status"
                )
                return

            session_data = doc.to_dict()
            notifications = session_data.get("notificaciones", [])

            # Update status for all notifications
            updated_notifications = [
                {**notif, "status": status} for notif in notifications
            ]

            await doc_ref.update(
                {
                    "notificaciones": updated_notifications,
                    "ultimaActualizacion": datetime.now(),
                }
            )

            logger.info(
                f"Successfully updated notification status to '{status}' for session {session_id} in Firestore"
            )

        except Exception as e:
            logger.error(
                f"Error updating notification status in Firestore for session {session_id}: {str(e)}",
                exc_info=True,
            )
            raise

    async def delete_notification(self, notification_id: str) -> bool:
        """Delete notification session from Firestore."""
        try:
            logger.info(
                f"Deleting notification session {notification_id} from Firestore"
            )
            doc_ref = self._notification_ref(notification_id)
            await doc_ref.delete()
            logger.info(
                f"Successfully deleted notification session {notification_id} from Firestore"
            )
            return True

        except Exception as e:
            logger.error(
                f"Error deleting notification session {notification_id} from Firestore: {str(e)}",
                exc_info=True,
            )
            return False