import os
import shelve as shelf
import platform
from pathlib import Path
from utils import die


class Shelf:
    def __init__(self, filename: str):
        self.file: Path = None
        self.db = None

        os_type: str = platform.system()

        if os_type == 'Linux':
            self.file = os.environ.get('HOME') + '/.local/share/' + filename
        elif os_type == 'Windows':
            self.file = os.environ.get('APPDATA') + filename
        else:
            die('OS not supported', 2)


    def __enter__(self):
        # Open the shelf and load data into self.db
        self.db = shelf.open(self.file, writeback=True)
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        # Save any updates to the shelf
        if self.db is not None:
            self.db.sync()
            self.db.close()

    def update(self, entries: dict):
        db_values = self.db.values()

        if db_values:
            dirs, projects, _ = db_values
            new_dirs, new_projects, _ = entries.values()

            for dir in new_dirs:
                if dir not in dirs:
                    self.db['dirs'].append(dir)

            for project in new_projects:
                if project not in projects:
                    self.db['projects'].append(project)
        else:
            for k, v in entries.items():
                self.db[k] = v