import os
import sys
import time
from multiprocessing.pool import ThreadPool

import requests
import sqlalchemy
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker


PRICING_DB_URL = os.environ.get('PRICING_DB_URL', '')
OWS_PRICING_URL = os.environ.get('OWS_PRICING_URL', '')
STATUS_BEFORE = os.environ.get('STATUS_BEFORE', 'NeedPhase1Migration')
STATUS_AFTER = os.environ.get('STATUS_AFTER', 'Phase1MigrationDone')
PRODUCT_BATCH_SIZE = os.environ.get('PRODUCT_BATCH_SIZE', '10')
POOL_SIZE = os.environ.get('POOL_SIZE', '4')


GET_PRODUCTS_QUERY = """
SELECT pms.product_id
FROM product_migration_status pms
LEFT OUTER JOIN product_orchard_pricing_tier popt on pms.product_id = popt.product_id
WHERE pms.migration_status=:status_before
AND popt.product_orchard_pricing_tier_id IS NULL
LIMIT :product_batch_size
"""


db_engine = create_engine(PRICING_DB_URL)
db_session = sessionmaker(bind=db_engine)


def get_session():
    return db_session()


def get_products():
    session = get_session()

    try:
        result = session.execute(
            sqlalchemy.text(GET_PRODUCTS_QUERY),
            {
                'status_before': STATUS_BEFORE,
                'product_batch_size': int(PRODUCT_BATCH_SIZE)
            }
        ).fetchall()
        session.commit()
        return result
    except Exception as e:
        session.rollback()
        raise e
    finally:
        session.close()


def get_migration_url(product_id):
    qs = 'status_before={0}&status_after={1}'.format(
        STATUS_BEFORE, STATUS_AFTER)
    return '{0}/legacy/music/product/{1}/execute?{2}'.format(
            OWS_PRICING_URL, product_id, qs)


def get_time(start, end):
    diff = end - start
    return '%.2f'%(diff)


def migrate_product(row):
    print('About to migrate product {0}'.format(row['product_id']))

    t3 = time.time()
    pricing_response = requests.get(get_migration_url(row['product_id']))
    t4 = time.time()

    if pricing_response.status_code == 400:
        print('Product {0} has already been migrated'.format(
            row['product_id']))
        return
    elif pricing_response.status_code != 200:
        pricing_response.raise_for_status()

    print('Migrated product {0} in {1}s'.format(
        row['product_id'], get_time(t3, t4)))


try:
    print('About to fetch products to migrate')

    t1 = time.time()
    product_rows = get_products()
    t2 = time.time()

    print('Fetched {0} products to migrate in {1}s'.format(
        len(product_rows), get_time(t1, t2)))

    with ThreadPool(int(POOL_SIZE)) as p: p.map(migrate_product, product_rows)

    t5 = time.time()
    print('Done migrating in {0}s'.format(get_time(t1, t5)))

    sys.exit()
except Exception as e:
    sys.exit(e)