import json
import boto3
import os
import time

S3_BUCKET = os.environ.get('S3_BUCKET')
SOURCE_PREFIX = os.environ.get('SOURCE_PREFIX')
DESTINATION_PREFIX = os.environ.get('DESTINATION_PREFIX')

transcribe_client = boto3.client('transcribe')

def lambda_handler(event, context):
    # Transcribe meeting recording to text
    recording_name = event['Records'][0]['s3']['object']['key']
    job_tokens = recording_name.split('/')[1].split('.')
    
    job_name = '{}_{}'.format(job_tokens[0], int(time.time()))
    media_format = job_tokens[1]
    media_uri = 's3://{}/{}'.format(S3_BUCKET, recording_name)
    output_key = '{}/{}.txt'.format(DESTINATION_PREFIX, job_name)
    
    try:
        job_args = {
            'TranscriptionJobName': job_name,
            'Media': {'MediaFileUri': media_uri},
            'MediaFormat': media_format,
            'IdentifyLanguage': True,
            'OutputBucketName':S3_BUCKET,
            'OutputKey':output_key
        }
        response = transcribe_client.start_transcription_job(**job_args)
        job = response['TranscriptionJob']
        print("Started transcription job {}.".format(job_name))
    except Exception:
        print("Couldn't start transcription job %s.".format(job_name))
        raise
    
    return {
        'statusCode': 200,
        'body': json.dumps('Started transcription job {}'.format(job_name))
    }