from __future__ import with_statement

import os

from alembic import context
from sqlalchemy import engine_from_config, pool
from logging.config import fileConfig
from urllib import unquote, quote
from peewee import SqliteDatabase

from data.database import all_models, db
from app import app
from data.model.sqlalchemybridge import gen_sqlalchemy_metadata
from util.morecollections import AttrDict

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
db_uri = unquote(app.config['DB_URI'])
if 'GENMIGRATE' in os.environ:
    docker_host = os.environ.get('DOCKER_HOST')
    docker_host_ip = docker_host[len('tcp://'):].split(':')[0]
    if os.environ.get('GENMIGRATE') == 'mysql':
        db_uri = 'mysql+pymysql://root:password@%s/genschema' % (docker_host_ip)
    else:
        db_uri = 'postgresql://postgres@%s/genschema' % (docker_host_ip)

if 'DB_URI' in os.environ:
    db_uri = os.environ['DB_URI']

app.config['DB_URI'] = db_uri

config = context.config
config.set_main_option('sqlalchemy.url', db_uri)

# Interpret the config file for Python logging.
# This line sets up loggers basically.
fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = gen_sqlalchemy_metadata(all_models)
tables = AttrDict(target_metadata.tables)

# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.

def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = unquote(app.config['DB_URI'])
    context.configure(url=url, target_metadata=target_metadata, transactional_ddl=True)

    with context.begin_transaction():
        context.run_migrations(tables=tables)

def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """

    if isinstance(db.obj, SqliteDatabase) and not 'GENMIGRATE' in os.environ and not 'DB_URI' in os.environ:
        print ('Skipping Sqlite migration!')
        return

    engine = engine_from_config(
                config.get_section(config.config_ini_section),
                prefix='sqlalchemy.',
                poolclass=pool.NullPool)

    connection = engine.connect()
    context.configure(
                connection=connection,
                target_metadata=target_metadata
                )

    try:
        with context.begin_transaction():
            context.run_migrations(tables=tables)
    finally:
        connection.close()

if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()