import json
import os
import urllib3

bot_token = os.environ.get('SLACK_BOT_TOKEN')


def send_slack_message(channel, message, blocks=[], attachments=[]):
    http = urllib3.PoolManager()

    body = {
        "channel": channel,
    }
    
    if isinstance(message, dict):
        body['message'] = message
    else:
        body['text'] = message
        
    if blocks:
        body['blocks'] = blocks

    if attachments:
        body['attachments'] = attachments

    response = http.request(
        "POST", "https://slack.com/api/chat.postMessage", 
        body=json.dumps(body).encode('utf8'), headers={
            'Content-Type': 'application/json; charset=utf8',
            'Authorization': 'Bearer ' + bot_token,
        }
    )

    result = json.loads(response.data.decode('utf8'))
    if not result['ok']:
        raise Exception("Unable to post message: {}".format(result['error']))



def lambda_handler(event, context):
    send_slack_message(
        event.get('channel'),
        event.get('message'),
        event.get('blocks'),
        event.get('attachments')
    )

    return {
        "status": "ok"
    }