feat: define Pydantic schemas for data validation and API serialization

backend/app/schemas/schemas.py

@@ -1 +1,111 @@
-#
+import uuid
+import datetime
+from typing import Optional, List 
+from pydantic import BaseModel, Field, ConfigDict
+
+# AUTHENTICATION & USER SCHEMAS
+class GoogleAuthRequest(BaseModel):
+    token_id: str= Field(description= "Google OAuth ID Token received on the frontend")
+    
+class Token(BaseModel):
+    access_token: str
+    token_type: str= "bearer"
+    
+class TokenPayload(BaseModel):
+    sub: Optional[str]= None
+
+class UserBase(BaseModel):
+    email: str
+    full_name: Optional[str]= None
+    picture_url: Optional[str]= None
+
+class UserResponse(UserBase):
+    id: uuid.UUID
+    google_id: str
+    credits: int
+    last_credit_refresh: datetime.datetime
+    created_at: datetime.datetime
+    
+    model_config= ConfigDict(from_attributes= True)
+
+# WATCHLIST SCHEMAS
+class WatchlistBase(BaseModel):
+    ticker: str= Field(..., description= "Stock symbol, e.g., AAPL or TCS.NS")
+
+class WatchlistCreate(WatchlistBase):
+    pass
+
+class WatchlistResponse(WatchlistBase):
+    id: uuid.UUID
+    user_id: uuid.UUID
+    created_at: datetime.datetime
+    
+    model_config= ConfigDict(from_attributes= True)
+
+# ALERT SCHEMAS
+class AlertBase(BaseModel):
+    ticker: str= Field(..., description= "Stock symbol to monitor")
+    target_price: float= Field(..., gt=0, description= "Price target that triggers the alert")
+    condition: str= Field(..., description= "Trigger condition: 'above' or 'below'")
+
+class AlertCreate(AlertBase):
+    pass 
+
+class AlertUpdate(BaseModel):
+    target_price: Optional[float]= Field(None, gt=0)
+    condition: Optional[str]= None
+    is_active: Optional[bool]= None
+
+class AlertResponse(AlertBase):
+    id: uuid.UUID
+    user_id: uuid.UUID
+    is_active: bool
+    created_at: datetime.datetime
+    
+    model_config= ConfigDict(from_attributes= True)
+    
+# STOCK HISTORY SCHEMAS
+class StockHistoryBase(BaseModel):
+    ticker: str
+    timestamp: datetime.datetime
+    open: float
+    high: float
+    low: float
+    close: float
+    volume: int
+    
+class StockHistoryResponse(StockHistoryBase):
+    model_config= ConfigDict(from_attributes= True)
+    
+# AI INSIGHTS & CHAT SCHEMAS
+class GeminiInsightResponse(BaseModel):
+    ticker: str
+    bullish_probability: int= Field(..., ge=0, le= 100)
+    reason: str
+    credits_remaining: int
+    
+# PAYMENT & RAZORPAY SCHEMAS
+class PaymentOrderCreate(BaseModel):
+    amount: int= Field(..., gt=0, description= "Amount in Rupees, e.g., 100 or 200")
+    
+class PaymentOrderResponse(BaseModel):
+    order_id: str
+    amount: int
+    currency: str= "INR"
+
+class PaymentCaptureRequest(BaseModel):
+    razorpay_order_id: str
+    razorpay_payment_id: str
+    razorpay_signature: str
+    
+class PaymentTransactionResponse(BaseModel):
+    id: uuid.UUID
+    user_id: uuid.UUID
+    razorpay_order_id: str
+    razorpay_payment_id: Optional[str]= None
+    amount: int
+    status: str
+    credits_credited: int
+    created_at: datetime.datetime
+    
+    model_config= ConfigDict(from_attributes= True)