"""
Hugging Face Leaderboard Service
Manages leaderboard data persistence using HF Hub
"""

import json
import os
from datetime import datetime
from typing import List, Dict, Optional
from huggingface_hub import HfApi, hf_hub_download, CommitOperationAdd
import logging

logger = logging.getLogger(__name__)


class HFLeaderboardService:
    """
    Service for managing leaderboard data on Hugging Face Hub
    Stores leaderboard as a JSON file in the current HF Space repository
    """

    def __init__(self, repo_id: Optional[str] = None, token: Optional[str] = None):
        """
        Initialize HF Leaderboard Service

        Args:
            repo_id: HF Hub repository ID (format: username/repo-name)
                    If not provided, uses SPACE_ID env var (auto-set in HF Spaces)
            token: HF API token (if not provided, uses HF_TOKEN env var)
        """
        # Use SPACE_ID if available (automatically set in HF Spaces)
        self.repo_id = repo_id or os.getenv("SPACE_ID")
        if not self.repo_id:
            raise ValueError("No repo_id provided and SPACE_ID env var not set. Cannot determine target repository.")

        self.token = token or os.getenv("HF_TOKEN")
        self.api = HfApi()
        self.leaderboard_file = "leaderboard.json"
        self.repo_type = "space"  # Store in Space repo, not separate dataset

        if not self.token:
            logger.warning("No HF token provided. Read-only mode (if repo is public)")

        logger.info(f"HF Leaderboard Service initialized for Space: {self.repo_id}")

    def _save_to_hub(self, data: List[Dict]):
        """
        Save leaderboard data to HF Hub using best practice commit pattern

        Args:
            data: List of leaderboard entries
        """
        if not self.token:
            raise ValueError("No HF token available for writing")

        # Create temporary file with leaderboard data
        temp_file = f"/tmp/{self.leaderboard_file}"
        with open(temp_file, "w") as f:
            json.dump({
                "leaderboard": data,
                "last_updated": datetime.utcnow().isoformat(),
                "version": "1.0"
            }, f, indent=2)

        # Commit to HF Hub using best practice pattern
        try:
            operations = [
                CommitOperationAdd(
                    path_or_fileobj=temp_file,
                    path_in_repo=self.leaderboard_file
                )
            ]

            self.api.create_commit(
                repo_id=self.repo_id,
                operations=operations,
                commit_message=f"update leaderboard - {datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S')} utc",
                repo_type=self.repo_type,
                token=self.token
            )

            logger.info(f"Leaderboard saved to HF Hub: {self.repo_id}")
        except Exception as e:
            logger.error(f"Failed to commit to HF Hub: {e}")
            raise
        finally:
            # Clean up temp file
            if os.path.exists(temp_file):
                os.remove(temp_file)

    def _load_from_hub(self) -> List[Dict]:
        """
        Load leaderboard data from HF Hub

        Returns:
            List of leaderboard entries
        """
        try:
            # Download file from HF Hub
            file_path = hf_hub_download(
                repo_id=self.repo_id,
                filename=self.leaderboard_file,
                repo_type=self.repo_type,
                token=self.token
            )

            with open(file_path, "r") as f:
                data = json.load(f)
                return data.get("leaderboard", [])
        except Exception as e:
            logger.warning(f"Failed to load from HF Hub: {e}. Returning empty leaderboard.")
            return []

    def get_leaderboard(self) -> List[Dict]:
        """
        Get current leaderboard data

        Returns:
            List of leaderboard entries sorted by rank
        """
        return self._load_from_hub()

    def add_entry(self, entry: Dict) -> bool:
        """
        Add new entry to leaderboard

        Args:
            entry: Leaderboard entry with keys: initials, level, round, passagesPassed, date

        Returns:
            True if successful, False otherwise
        """
        if not self.token:
            raise ValueError("No HF token available for writing")

        try:
            # Load current leaderboard
            leaderboard = self._load_from_hub()

            # Add new entry
            leaderboard.append(entry)

            # Sort leaderboard (highest level first, then round, then passages)
            leaderboard = self._sort_leaderboard(leaderboard)

            # Keep only top 10
            leaderboard = leaderboard[:10]

            # Save back to hub
            self._save_to_hub(leaderboard)

            logger.info(f"Added entry to leaderboard: {entry['initials']} - Level {entry['level']}")
            return True
        except Exception as e:
            logger.error(f"Failed to add entry: {e}")
            return False

    def update_leaderboard(self, leaderboard: List[Dict]) -> bool:
        """
        Replace entire leaderboard with new data

        Args:
            leaderboard: Complete leaderboard data

        Returns:
            True if successful, False otherwise
        """
        if not self.token:
            raise ValueError("No HF token available for writing")

        try:
            # Sort and limit to top 10
            sorted_board = self._sort_leaderboard(leaderboard)[:10]
            self._save_to_hub(sorted_board)
            return True
        except Exception as e:
            logger.error(f"Failed to update leaderboard: {e}")
            return False

    def _sort_leaderboard(self, entries: List[Dict]) -> List[Dict]:
        """
        Sort leaderboard entries by performance

        Args:
            entries: List of leaderboard entries

        Returns:
            Sorted list (best first)
        """
        return sorted(entries, key=lambda x: (
            -x.get('level', 0),  # Higher level is better
            -x.get('round', 0),  # Higher round is better
            -x.get('passagesPassed', 0),  # More passages is better
            x.get('date', '')  # Newer is better (date sorts ascending)
        ))

    def clear_leaderboard(self) -> bool:
        """
        Clear all leaderboard data (admin function)

        Returns:
            True if successful, False otherwise
        """
        if not self.token:
            raise ValueError("No HF token available for writing")

        try:
            self._save_to_hub([])
            logger.info("Leaderboard cleared")
            return True
        except Exception as e:
            logger.error(f"Failed to clear leaderboard: {e}")
            return False