Update trade.py

Author: KOSASIH

models/trade.py

@@ -1,13 +1,77 @@
+from flask_sqlalchemy import SQLAlchemy
+from sqlalchemy.exc import IntegrityError
 from models import Currency
 
+db = SQLAlchemy()
+
 class Trade(db.Model):
+    __tablename__ = 'trades'
+
     id = db.Column(db.Integer, primary_key=True)
-    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
-    currency_id = db.Column(db.Integer, db.ForeignKey('currency.id'))
+    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
+    currency_id = db.Column(db.Integer, db.ForeignKey('currencies.id'), nullable=False)
     amount = db.Column(db.Float, nullable=False)
     price = db.Column(db.Float, nullable=False)
 
     currency = db.relationship('Currency', backref='trades')
 
     def __repr__(self):
-        return f"Trade('{self.user_id}', {self.amount}, {self.price}, {self.currency.symbol})"
+        return f"Trade('{self.user_id}', {self.amount}, {self.price}, '{self.currency.symbol}')"
+
+    def total_value(self) -> float:
+        """Calculate the total value of the trade."""
+        return self.amount * self.price
+
+    @classmethod
+    def create(cls, user_id: int, currency_id: int, amount: float, price: float):
+        """Create a new trade instance and add it to the database."""
+        new_trade = cls(user_id=user_id, currency_id=currency_id, amount=amount, price=price)
+        try:
+            db.session.add(new_trade)
+            db.session.commit()
+            return new_trade
+        except IntegrityError:
+            db.session.rollback()
+            raise ValueError("Failed to create trade. Please check the provided data.")
+
+    @classmethod
+    def get_all(cls):
+        """Retrieve all trades from the database."""
+        return cls.query.all()
+
+    @classmethod
+    def get_by_user(cls, user_id: int):
+        """Retrieve all trades for a specific user."""
+        return cls.query.filter_by(user_id=user_id).all()
+
+# Example usage
+if __name__ == "__main__":
+    from flask import Flask
+
+    app = Flask(__name__)
+    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///trades.db'
+    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+    db.init_app(app)
+
+    with app.app_context():
+        db.create_all()  # Create the database tables
+
+        # Example of creating a trade
+        try:
+            # Assuming you have a user with ID 1 and a currency with ID 1
+            trade = Trade.create(user_id=1, currency_id=1, amount=10, price=50000)
+            print(f"Trade created: {trade}")
+
+            # Calculate total value of the trade
+            print(f"Total value of the trade: {trade.total_value()}")
+
+            # Retrieve all trades
+            all_trades = Trade.get_all()
+            print(all_trades)
+
+            # Retrieve trades by user
+            user_trades = Trade.get_by_user(1)
+            print(user_trades)
+
+        except ValueError as e:
+            print(e)