Add dashboard endpoint

backend/app/routers/me_v1.py

@@ -1,6 +1,8 @@
+from datetime import UTC, datetime, timedelta
 from uuid import UUID
 from fastapi import APIRouter, HTTPException
 from fastapi.params import Depends
+from sqlalchemy import select
 from sqlalchemy.orm import Session as DbSession
 
 from app.database import get_db
@@ -10,6 +12,9 @@ from app.schemas.user import PasswordUpdate, UserUpdate, User
 from app.security.jwt_bearer import JWTBearer
 from app.services import session_service, user_service
 from app.util.errors import InvalidStateError, NotFoundError
+from app.schemas.dashboard import DashboardResponse, DashboardStats
+from app.models.transaction import Transaction as DbTransaction
+from app.schemas.transaction import TransactionStatus
 
 router = APIRouter(prefix="/me", tags=["Me (v1)"])
 
@@ -108,4 +113,75 @@ async def delete_user_session(
         )
     except NotFoundError:
         raise HTTPException(status_code=404, detail="session_not_found")
-    return list()
+    return list()
+
+@router.get(path="/dashboard", response_model=DashboardResponse)
+async def get_dashboard(
+    db: DbSession = Depends(get_db),
+    token: AccessToken = Depends(JWTBearer()),
+):
+    """
+    Get dashboard information for the currently authenticated user.
+    """
+    # Currently ongoing transaction
+    stmt_current_transaction = select(DbTransaction).where(DbTransaction.user_id == token.subject).where(DbTransaction.status == TransactionStatus.ONGOING)
+    current_transaction = db.execute(stmt_current_transaction).scalars().first()
+
+    # Common base query
+    stmt_base = select(DbTransaction).where(DbTransaction.user_id == token.subject).where( DbTransaction.status == TransactionStatus.ENDED).order_by(DbTransaction.ended_at.desc())
+
+    # 5 most recent transactions
+    stmt_transactions_recent = stmt_base.limit(5)
+    recent_transactions = db.execute(stmt_transactions_recent).scalars().all()
+
+    # Calculate beginning of the current and previous month
+    current_date = datetime.now(UTC).replace(hour=0, minute=0, second=0, microsecond=0, tzinfo=None)
+
+    beginning_current_month = current_date.replace(day=1)
+
+    beginning_previous_month = beginning_current_month.replace(
+        year=(beginning_current_month.year - 1 if beginning_current_month.month == 1 else beginning_current_month.year),
+        month=(12 if beginning_current_month.month == 1 else beginning_current_month.month - 1)
+    )
+
+    # Transactions for total calculations
+    stmt_transactions = stmt_base.where(DbTransaction.ended_at >= beginning_previous_month)
+    transactions = db.execute(stmt_transactions).scalars().all()
+
+    # Current month totals
+    count = 0
+    energy_total = 0
+    cost_total = 0
+
+    # Previous month totals
+    count_previous = 0
+    energy_total_previous = 0
+    cost_total_previous = 0
+
+    # Calculate totals
+    for trans in transactions:
+        trans_energy = trans.meter_end - trans.meter_start
+        trans_cost = trans_energy * trans.price
+        if trans.ended_at >= beginning_current_month:
+            # Current month
+            energy_total += trans_energy
+            cost_total += trans_cost
+            count += 1
+        else:
+            # Previous month
+            energy_total_previous += trans_energy
+            cost_total_previous += trans_cost
+            count_previous += 1
+    
+    return DashboardResponse(
+        stats=DashboardStats(
+            transaction_count=count,
+            transaction_count_previous=count_previous,
+            transaction_energy_total=energy_total,
+            transaction_energy_total_previous=energy_total_previous,
+            transaction_cost_total=cost_total,
+            transaction_cost_total_previous=cost_total_previous
+        ),
+        current_transaction=current_transaction,
+        recent_transactions=recent_transactions
+    )