import os
import json
import shutil
import zipfile
from datetime import datetime
from typing import List, Dict


class SyncManager:
    """
    Manages the creation of export packages and synchronization of files.
    """

    def __init__(self):
        self.manifest_name = "bridge_manifest.json"

    def create_export_package(
        self,
        source_root: str,
        changes: Dict[str, List[str]],
        output_zip: str,
        commit_message: str
    ) -> None:
        """
        Creates a ZIP file containing modified/added files and a manifest.
        """
        with zipfile.ZipFile(output_zip, "w", zipfile.ZIP_DEFLATED) as zip_file:
            manifest_data = {
                "timestamp": datetime.now().isoformat(),
                "commit_message": commit_message,
                "changes": changes
            }
            manifest_content = json.dumps(manifest_data, indent=4)
            zip_file.writestr(self.manifest_name, manifest_content)
            for category in ["added", "modified"]:
                for relative_path in changes.get(category, []):
                    full_path = os.path.join(source_root, relative_path)
                    if os.path.exists(full_path):
                        zip_file.write(full_path, relative_path)

    def apply_package(self, package_path: str, destination_root: str) -> str:
        """
        Extracts the package and applies changes to the destination folder.
        """
        with zipfile.ZipFile(package_path, "r") as zip_file:
            with zip_file.open(self.manifest_name) as f:
                manifest = json.load(f)
            changes = manifest.get("changes", {})
            for relative_path in changes.get("deleted", []):
                target_path = os.path.join(destination_root, relative_path)
                if os.path.exists(target_path):
                    os.remove(target_path)
            for file_info in zip_file.infolist():
                if file_info.filename == self.manifest_name:
                    continue
                zip_file.extract(file_info, destination_root)
            return manifest.get("commit_message", "")

    def copy_file(self, source_path: str, destination_path: str) -> None:
        """
        Copies a single file from source to destination, creating directories.
        """
        os.makedirs(os.path.dirname(destination_path), exist_ok=True)
        shutil.copy2(source_path, destination_path)