import os
import sys
import json
import tomli


class PresetParseError(Exception):
    pass


class Preset:
    def __collect_preset_files(self):
        result = []
        for root, dirs, files in os.walk(self.__path):
            for f in files:
                name = f
                path = os.path.join(root, f)

                result.append((name, path))

        return result


    def __apply_preset_file(self, data):
        bootstrap = data.get('bootstrap', None)
        contents = data.get('contents', None)
        if bootstrap is not None:
            self.__bootstrap = bootstrap

        if contents is not None:
            for dest, src in contents.items():
                dest_list = self.__contents.get(dest, [])

                for p in src:
                    dest_list.append(p)

                self.__contents[dest] = dest_list


    def __read_preset_files(self):
        for n, p in self.__files:
            data = None
            try:
                f = open(p, mode='rb')
                data = tomli.load(f)
            except Exception as e:
                raise ParseError('Err: Failed to parse seed file {}: {}'.format(seed_path, e))

            self.__apply_preset_file(data)


    def __init__(self, path):
        self.__bootstrap = {}
        self.__contents = {}
        self.__path = path
        self.__files = self.__collect_preset_files()
        self.__files = sorted(self.__files, key=lambda tup: tup[0])
        self.__read_preset_files()


    def contents(self):
        return self.__contents


    def bootstrap_program(self):
        return self.__bootstrap.get('bootstrap_exec', None)