import datetime
import uuid
from peewee import *

DATABASE = 'budget.db'
instance = SqliteDatabase(DATABASE, pragmas=[('foreign_keys', 'on')])

def create_tables():
    """Helper function to create database tables. Should be called manually."""
    with instance:
        instance.create_tables([User, TransactionCategory, Transaction])
    
def add_user():
    # Make my user.
    instance.connect()
    User.create(username='ciphercules')
    instance.close()

def add_default_categories():
    """Helper function to add default categories. Should be called manually."""
    categories = [
        ("food", ["snacks", "fast_food", "groceries", "restaurant"]),
        ("clothing", []),
        ("event", ["event_food", "birthday", "movie_theater"]),
        ("finance", ["interest"]),
        ("hobby", ["gym", "game_development", "projects", "education"]),
        ("home_improvement", []),
        ("pet", ["dog_health", "dog_food"]),
        ("media", ["book", "music", "television", "video_game"]),
        ("health", ["medicine"]),
        ("transit", ["car_insurance", "car_registration", "gas", "parking", "taxi", "car_maintenance"]),
        ("utilities", ["electricity", "natural_gas", "laundry", "cell_phone", "trash", "water"]),
        ("rent", []),
    ]

    instance.connect()
    with instance.atomic():
        for category in categories:
            parent, children = category
            parent_db = TransactionCategory.create(name=parent)
            for child in children:
                TransactionCategory.create(name=child, parent=parent_db)

class BaseModel(Model):
    class Meta:
        database = instance

class User(BaseModel):
    uuid = UUIDField(unique=True, primary_key=True, default=uuid.uuid4())
    username = CharField(unique=True)

class TransactionCategory(BaseModel):
    primary_key = AutoField(primary_key=True)
    name = CharField(unique=True)
    parent = ForeignKeyField('self', null=True, backref='children')

class Transaction(BaseModel):
    # Metadata
    primary_key = AutoField(primary_key=True)
    created_date = DateTimeField(default=datetime.datetime.now)
    source_file=CharField(null=True)
    type = IntegerField()
    user = ForeignKeyField(User, backref='transactions')

    # Real data
    transaction_date = DateTimeField()
    description = CharField()
    amount = FloatField()
    subcategory = ForeignKeyField(TransactionCategory, backref='+', null=True)
    notes = CharField(null=True)

if __name__ == "__main__":
    create_tables()
    add_user()
    add_default_categories()