import json
import os
import re
from typing import List

from million.model.fb_export import FacebookExport
from million.model.message import Message


class FacebookExportParser:

    def __init__(self):
        pass

    def parse(self, file_dir) -> FacebookExport:
        files = [file_dir +
                 f for f in os.listdir(file_dir) if f.endswith('.json')]
        messages = []
        participants = []
        for file in files:
            print(file)
            with open(file, 'rb') as f:
                json_data = self.__read_broken_fb_json(f.read())
                messages += [Message(**m) for m in json_data['messages']]
                participants += json_data['participants']

        messages.sort(key=lambda m: m.timestamp_ms)
        return FacebookExport(messages=messages, participants=participants)

    def __read_broken_fb_json(self, binary_data):
        repaired = re.sub(
            rb'\\u00([\da-f]{2})',
            lambda m: bytes.fromhex(m.group(1).decode()),
            binary_data
        )
        return json.loads(repaired.decode('utf8'))