#!/bin/env python

import boto3
import json
import os
import uuid

from boto3.dynamodb.conditions import Attr, Key
from botocore.exceptions import ClientError


# example usage:
#  - add a new source key pair:
#    {"action": "add", "name": "<src-val>", "maintainer": "<someone>", "psk": "<key-val>"}
#    <key-val> will be randomly generated if not specified
#  - query for an existing key pair:
#    {"action": "query", "name": "<src-val>"}
#  - delete one source from db:
#    {"action": "del", "name": "<src-val>"}


def respond(err=None, res=None):
    resp = {
        "status": "ok",
        "result": res
    }
    if err:
        resp['status'] = "error"
        resp['msg'] = str(err)

    return resp


def init_db():
    _db = boto3.resource('dynamodb')
    source_table_name = os.getenv('ACTIVITYHUB_SOURCE_TABLE_NAME')
    try:
        src_table = _db.Table(source_table_name)
        #src_table = _db.Table('activity-hub-messages')
        src_table.load()
    except ClientError as e:
        print(f"error connecting dynamodb: {e}")
        raise
    return src_table


def lambda_handler(event, context):
    print("Received event: " + json.dumps(event))
    table = None
    try:
        table = init_db()
    except Exception as e:
        return respond(e, "error connecting to database")

    if event['action'] == 'add':
        _item = {
            'name': event['name'].lower(),
            'maintainer': event['maintainer'],
        }
        try:
            _item['psk'] = event['psk']
        except KeyError:
            _item['psk'] = uuid.uuid4().hex
        try:
            table.put_item(
                Item=_item, ConditionExpression='attribute_not_exists(psk)')
            return respond(res=_item)
        except Exception as e:
            return respond(e, "error adding item to database")

    elif event['action'] == 'query':
        try:
            result = table.get_item(Key={'name': event['name']})
            return respond(res=result['Item'])
        except Exception as e:
            return respond(e, "error querying item from database")

    elif event['action'] == 'del':
        try:
            result = table.delete_item(Key={'name': event['name']})
            #result = table.delete_item(Key=event['key'])
            return respond(res=result)
        except Exception as e:
            return respond(e, "error deleting item from database")

    return respond(res="nothing happend")


if __name__ == '__main__':
    print('test')