import boto3
import os
import random
import time
import pyarrow as pa
import pyarrow.dataset
import pprint

pp = pprint.PrettyPrinter(indent=4)

class Athena:
    def __init__(self, profile, output):
        self.session = boto3.session.Session(profile_name=profile)
        self.athena  = self.session.client("athena")
        self.output  = output

    def query(self, sql):
        q = Query(self, sql)
        q.run()
        return q

    def download(self, s3):
        bucket = s3.split("/")[2]
        file   = os.path.join(*s3.split("/")[3:])
        tmp    = f"/tmp/{random.random()}.bin"
        self.session.client('s3').download_file(bucket, file, tmp)

        return tmp

class Query:
    DATA_STYLE = 'parquet'

    def __init__(self, handler, sql):
        self.handler = handler
        self.athena  = handler.athena
        self.sql     = sql

    def run(self):
        out    = os.path.join(self.handler.output,
                              str(random.random()))
        config = {"OutputLocation": out}
        query  = f"unload ({self.sql}) to {repr(out)} " + \
                 f"with (format = '{self.DATA_STYLE}')"

        resp  = self.athena.start_query_execution(QueryString=query,
                                                  ResultConfiguration=config)
        self.query_id = resp['QueryExecutionId']
        return resp

    def status(self):
        return self.info()['Status']

    def info(self):
        res = self.athena.get_query_execution(QueryExecutionId=self.query_id)
        return res['QueryExecution']

    def results(self):
        tiedot = self.info()
        status = tiedot['Status']['State']

        while status in ['QUEUED', 'RUNNING']:
            time.sleep(5)
            status = self.status()['State']

        if status == "SUCCEEDED":
            # Because we're using `UNLOAD`, we get a manifest of the files
            # that make up our data.
            files   = self.manifest(tiedot).strip().split("\n")
            local   = [self.handler.download(f) for f in files]
            self.ds = pa.dataset.dataset(local)

            return self.ds
        else:
            return status # canceled or error

    def manifest(self, tiedot):
        manif = tiedot['Statistics']['DataManifestLocation']
        tmp   = self.handler.download(manif)
        with open(tmp, "r") as f:
            return f.read()