import json
import os
import requests

ID_MAPPING_JSON = 'channel_id_mapping.json'


class ChannelIdMapper:
    def __init__(self, token):
        self.token = token
        self._load_channel_id_mapping()

    def create_channel_dict(self):
        base_url = 'https://slack.com/api/conversations.list'
        headers = {'Authorization': f'Bearer {self.token}'}
        params = {
            'types': 'public_channel,private_channel',
            'limit': 1000
        }
        response = requests.get(base_url, headers=headers, params=params)
        data = response.json()

        channel_dict = {}
        if data['ok']:
            channels = data['channels']
            for channel in channels:
                channel_name = channel['name']
                channel_id = channel['id']
                channel_dict[channel_name] = channel_id
        else:
            print(f'Error: {data}')
        print(channel_dict)
        return channel_dict

    def _load_channel_id_mapping(self):
        if os.path.exists(ID_MAPPING_JSON):
            with open(ID_MAPPING_JSON, 'r') as f:
                channel_dict = json.load(f)
        else:
            channel_dict = self.create_channel_dict()
            with open(ID_MAPPING_JSON, 'w') as f:
                json.dump(channel_dict, f, indent=4)
        return channel_dict

    def get_channel_id(self, channel_name):
        channel_dict = self._load_channel_id_mapping()
        return channel_dict[channel_name]