from typing import Annotated

from fastapi import Depends
from sqlalchemy import Column, DateTime, Float, Integer, String, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import Session, sessionmaker

SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"

engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


db_dependency = Annotated[Session, Depends(get_db)]
Base = declarative_base()


def create_db_tables():
    """Create database tables safely with error handling"""
    import logging
    logger = logging.getLogger(__name__)
    
    try:
        # Check if tables already exist to avoid unnecessary DDL operations
        from sqlalchemy import inspect
        inspector = inspect(engine)
        existing_tables = inspector.get_table_names()
        
        if existing_tables:
            logger.info(f"Database tables already exist: {existing_tables}")
            return
        
        # Create tables with timeout protection
        logger.info("Creating database tables...")
        Base.metadata.create_all(bind=engine, checkfirst=True)
        logger.info("Database tables created successfully")
        
    except KeyboardInterrupt:
        logger.warning("Database creation interrupted by user")
        raise
    except Exception as e:
        logger.error(f"Error creating database tables: {e}")
        # Don't crash the app - tables might already exist
        pass


def clear_all_data():
    """Clear all data from the database (useful for testing)"""
    db = SessionLocal()
    try:
        db.query(DBTransaction).delete()
        db.query(DBReceipt).delete()
        db.query(DBUploadedFile).delete()
        db.commit()
    finally:
        db.close()


# Transactions table
class DBTransaction(Base):
    __tablename__ = "transactions"

    id = Column(Integer, primary_key=True, index=True)
    transaction_id = Column(String, index=True)
    amount = Column(Float, nullable=False)
    date = Column(DateTime, nullable=False)
    vendor = Column(String, nullable=False)
    description = Column(String, nullable=True)
    category = Column(String, nullable=True)
    tax_amount = Column(Float, nullable=True)
    categorisation_id = Column(String, nullable=True)
    user_id = Column(String, nullable=True)

    # Additional QuickBooks CSV columns
    TxnId = Column(String, nullable=True)
    AccountType = Column(String, nullable=True)
    AccountNumber = Column(String, nullable=True)
    TransactionDate = Column(String, nullable=True)
    TransactionType = Column(String, nullable=True)
    ChequeNumber = Column(String, nullable=True)
    Description1 = Column(String, nullable=True)
    Description2 = Column(String, nullable=True)
    VendorId = Column(String, nullable=True)
    VendorName = Column(String, nullable=True)
    AccountId = Column(String, nullable=True)
    AccountName = Column(String, nullable=True)


# Uploaded Files table
class DBUploadedFile(Base):
    __tablename__ = "uploaded_files"

    id = Column(Integer, primary_key=True, index=True)
    file_id = Column(String, unique=True, index=True)
    filename = Column(String, nullable=False)
    file_path = Column(String, nullable=False)
    file_type = Column(String, nullable=False)
    upload_date = Column(DateTime, nullable=False)
    status = Column(String, nullable=False, default="uploaded")


# Receipts table
class DBReceipt(Base):
    __tablename__ = "receipts"

    id = Column(Integer, primary_key=True, index=True)
    receipt_id = Column(String, unique=True, index=True)
    file_id = Column(String, unique=True, index=True)
    amount = Column(Float, nullable=False)
    date = Column(DateTime, nullable=False)
    vendor = Column(String, nullable=False)
    description = Column(String, nullable=True)
    category = Column(String, nullable=True)
    tax_amount = Column(Float, nullable=True)
    confidence = Column(Float, nullable=True)
    extraction_success = Column(String, nullable=True)
    error_message = Column(String, nullable=True)
    receipt_currency = Column(String, nullable=True)
    receipt_location = Column(String, nullable=True)
    calculated_tax = Column(Float, nullable=True)
    is_depreciable = Column(String, nullable=True)  # Store as string "True"/"False"
    name_of_asset = Column(String, nullable=True)  # Name/description of the asset
    cca_rate = Column(Float, nullable=True)
    useful_life = Column(Integer, nullable=True)
    residual_value = Column(Float, nullable=True)