"""File handling for MAX surface."""
import os
import aiohttp
from pathlib import Path


class FileHandler:
    def __init__(self, workspace_root: str):
        self.workspace_root = workspace_root

    def _make_unique_filename(self, directory: str, filename: str) -> str:
        base = Path(filename).stem
        ext = Path(filename).suffix
        candidate = filename
        counter = 1
        while os.path.exists(os.path.join(directory, candidate)):
            candidate = f"{base} ({counter}){ext}"
            counter += 1
        return candidate

    async def download_attachment(
        self,
        download_url: str,
        filename: str,
        agent_workspace: str,
        headers: dict = None,
    ) -> str:
        full_dir = os.path.join(self.workspace_root, agent_workspace.strip("/"))
        os.makedirs(full_dir, exist_ok=True)

        unique_name = self._make_unique_filename(full_dir, filename)
        filepath = os.path.join(full_dir, unique_name)

        async with aiohttp.ClientSession() as session:
            async with session.get(download_url, headers=headers) as resp:
                resp.raise_for_status()
                with open(filepath, "wb") as f:
                    f.write(await resp.read())

        return unique_name

    def read_outgoing_file(self, workspace_path: str, agent_workspace: str) -> bytes:
        full_dir = os.path.join(self.workspace_root, agent_workspace.strip("/"))
        filepath = os.path.join(full_dir, workspace_path.lstrip("/"))
        with open(filepath, "rb") as f:
            return f.read()

    def file_exists(self, workspace_path: str, agent_workspace: str) -> bool:
        full_dir = os.path.join(self.workspace_root, agent_workspace.strip("/"))
        filepath = os.path.join(full_dir, workspace_path.lstrip("/"))
        return os.path.exists(filepath)