"""Configuration variables."""

import itertools
import os


# Environments
PROD_ENVIRONMENT = 'prod'
QA_ENVIRONMENT = 'qa'
DEV_ENVIRONMENT = 'dev'
TEST_ENVIRONMENT = 'test'
ENVIRONMENT = os.environ.get('Environment', DEV_ENVIRONMENT)


# Error logging
SENTRY = os.environ.get('SENTRY_DSN') or None

# S3
S3_BUCKET_NAME = os.environ.get('S3_BUCKET_NAME')

# These env vars are required for Snowflake itself to access our S3 bucket.
AWS_ACCESS_KEY_ID = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')

# Availability DB
AVAILABILITY_DB_CREDENTIALS = {
    'AVAIL_DB_USER': os.environ.get('AVAIL_DB_USER'),
    'AVAIL_DB_PASSWORD': os.environ.get('AVAIL_DB_PASSWORD'),
    'AVAIL_DB_HOST': os.environ.get('AVAIL_DB_HOST'),
    'AVAIL_DB_PORT': os.environ.get('AVAIL_DB_PORT', '3306'),
    'AVAIL_DB_NAME': os.environ.get('AVAIL_DB_NAME'),
}
AVAILABILITY_DB_CONNECTION_STRING = (
    'mysql+pymysql://{AVAIL_DB_USER}:{AVAIL_DB_PASSWORD}@{AVAIL_DB_HOST}'
    ':{AVAIL_DB_PORT}/{AVAIL_DB_NAME}'.format(**AVAILABILITY_DB_CREDENTIALS))
AVAILABILITY_DB_CONNECTION_ARGS = {'charset': 'utf8'}

# Snowflake DB
SNOWFLAKE_DB_CREDENTIALS = {
    'SF_USER': os.environ.get('SF_USER'),
    'SF_PASSWORD': os.environ.get('SF_PASSWORD'),
    'SF_ACCOUNT': os.environ.get('SF_ACCOUNT'),
}
SNOWFLAKE_DB_CONNECTION_STRING = (
    'snowflake://{SF_USER}:{SF_PASSWORD}@{SF_ACCOUNT}'.format(
        **SNOWFLAKE_DB_CREDENTIALS)
)
SF_DB_NAME = os.environ.get('SF_DB_NAME')
SF_WAREHOUSE = os.environ.get('SF_WAREHOUSE')
SF_ROLE = os.environ.get('SF_ROLE')

# Environment-specific checks
if ENVIRONMENT == TEST_ENVIRONMENT:
    AVAILABILITY_DB_CONNECTION_STRING = 'sqlite://'
    AVAILABILITY_DB_CONNECTION_ARGS = {}
    SNOWFLAKE_DB_CONNECTION_STRING = 'sqlite://'

if ENVIRONMENT in (PROD_ENVIRONMENT, QA_ENVIRONMENT):
    required_env_vars = itertools.chain(
        AVAILABILITY_DB_CREDENTIALS.items(),
        SNOWFLAKE_DB_CREDENTIALS.items(),
        (
            ('S3_BUCKET_NAME', S3_BUCKET_NAME),
            ('AWS_ACCESS_KEY_ID', AWS_ACCESS_KEY_ID),
            ('AWS_SECRET_ACCESS_KEY', AWS_SECRET_ACCESS_KEY),
            ('SF_ROLE', SF_ROLE),
        ),
    )
    for env_var_name, env_var_value in required_env_vars:
        assert env_var_value, (
            '{} is not present in the environment'.format(env_var_name))

    required_config_vars = (
        'AVAILABILITY_DB_CONNECTION_STRING',
        'SNOWFLAKE_DB_CONNECTION_STRING',
    )
    for config_var_name in required_config_vars:
        _locals = locals()
        assert _locals.get(config_var_name), (
            '{} is not set in config.py'.format(config_var_name))