import datetime
import pandas as pd
from sqlalchemy import Float, Integer, DateTime
from bigorm.abstract_models import BigQueryModel as Model, BigQueryColumn as Column
from bigorm.database import BigQueryDatabaseContext as DatabaseContext


class Example(Model):

    __tablename__ = 'example_dataset.example'  # The table will be named 'example' in the dataset 'example_dataset'
    example_integer = Column(Integer)  # Creates a column in the table named 'example_integer'
    example_float_property = Column(Float, nullable=False)  # Create a property that is not allowed to be empty with nullable=False

    # Create a column that automatically gets populated with the current datetime (when the object instance is created)
    example_date_created = Column(DateTime, nullable=False, default=datetime.datetime.utcnow)

with DatabaseContext(project='example_project'):
    if not Example.table_exists():
        Example.table_create()

    dataframe = pd.DataFrame({
        'example_float_property': [1.1, 2.2, 5.2],
        'example_date_created': [datetime.datetime.utcnow()] * 3,
        'example_integer_labeled_differently': [None, 3, None],
    })
    Example.create_from_pandas(
        df=dataframe,
        relabel={
            'example_integer_labeled_differently': 'example_integer'
        },
        create_method='load_job'
    )

    query_df = Example.query().all_as_pandas()