import os
import json
import logging
from typing import List, Dict, Any

import sys
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from ingestion.providers.base_provider import BaseStorageProvider

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("IngestionSync")


class SyncEngine:
    """
    Bộ điều phối đồng bộ không phụ thuộc vào nhà cung cấp cụ thể.
    Nhận vào bất kỳ BaseStorageProvider nào (SharePoint, Google Drive, NAS, ...).
    """
    def __init__(self, provider: BaseStorageProvider, state_file: str = "delta_state.json", output_file: str = "ingestion_output.json"):
        self.provider = provider
        self.state_file = state_file
        self.output_file = output_file

    def _load_sync_state(self) -> Dict:
        """Load sync state từ local file."""
        if os.path.exists(self.state_file):
            with open(self.state_file, "r", encoding="utf-8") as f:
                return json.load(f)
        return {}

    def _save_sync_state(self, state: Dict):
        """Save sync state ra local file."""
        with open(self.state_file, "w", encoding="utf-8") as f:
            json.dump(state, f, indent=2, ensure_ascii=False)

    def _upsert_to_local_db(self, new_items: List[Dict[str, Any]]):
        """Lưu kết quả vào local JSON (mô phỏng DB)."""
        db = {}
        if os.path.exists(self.output_file):
            with open(self.output_file, "r", encoding="utf-8") as f:
                try:
                    existing = json.load(f)
                    for item in existing:
                        db[item["id"]] = item
                except json.JSONDecodeError:
                    pass

        for item in new_items:
            item_id = item.get("id")
            if item.get("is_deleted"):
                if item_id in db:
                    db[item_id]["is_deleted"] = True
                else:
                    db[item_id] = item
            else:
                db[item_id] = item

        final_list = list(db.values())
        with open(self.output_file, "w", encoding="utf-8") as f:
            json.dump(final_list, f, indent=2, ensure_ascii=False)

        logger.info(f"Local database updated. Total items: {len(final_list)}")

    def run_sync(self):
        """Chạy đồng bộ: fetch changes từ provider -> lưu local."""
        logger.info("=== STARTING SYNC ===")

        sync_state = self._load_sync_state()
        if sync_state:
            logger.info("Found existing sync state. Performing INCREMENTAL sync.")
        else:
            logger.info("No sync state found. Performing FULL sync.")

        items, new_state = self.provider.fetch_changes(sync_state)
        logger.info(f"Provider returned {len(items)} change(s).")

        if items:
            self._upsert_to_local_db(items)

        self._save_sync_state(new_state)
        logger.info("Sync state saved.")


if __name__ == "__main__":
    from ingestion.providers.sharepoint_provider import SharePointProvider

    provider = SharePointProvider()
    engine = SyncEngine(provider)
    engine.run_sync()