from typing import BinaryIO, Protocol
from abc import abstractmethod
from glob import glob
import json
from pathlib import Path
from . import SoloTool

class SessionManager(Protocol):
    @abstractmethod
    def getSessions(self) -> list[str]:
        raise NotImplementedError

    @abstractmethod
    def loadSession(self, key: str, player=None) -> SoloTool:
        raise NotImplementedError

    @abstractmethod
    def saveSession(self, soloTool: SoloTool, key: str) -> None:
        raise NotImplementedError

    @abstractmethod
    def addSong(self, name: str, content: BinaryIO) -> None:
        raise NotImplementedError

class _FileSystemSessionManager(SessionManager):
    def __init__(self, songPool: str, sessionPath: str):
        self._songPool = Path(songPool)
        self._sessionPath = Path(sessionPath)

    def getSessions(self) -> list[str]:
        return [Path(f).stem for f in glob(f"{self._sessionPath}/*.json")]

    def loadSession(self, key: str, player=None) -> SoloTool:
        with open(self._sessionPath / f"{key}.json", "r") as f:
            session = json.load(f)

        st = SoloTool(self._songPool, player=player)

        for i, entry in enumerate(session):
            songPath = entry["path"]
            keyPoints = entry["key_points"]

            st.addSong(songPath)
            st._keyPoints[i] = keyPoints

        return st

    def saveSession(self, soloTool: SoloTool, key: str) -> None:
        session = []

        for i, song in enumerate(soloTool.songs):
            entry = {
                "path": song,
                "key_points" : soloTool._keyPoints[i]
            }
            session.append(entry)

        with open(self._sessionPath / f"{key}.json", "w") as f:
            json.dump(session, f)

    def addSong(self, name: str, content: BinaryIO):
        from shutil import copyfileobj
        newSong = self._songPool / name
        with open(newSong, "wb") as f:
            copyfileobj(content, f)

def getSessionManager(songPool: str, sessionPath: str) -> SessionManager:
    return _FileSystemSessionManager(songPool, sessionPath)