working on backend

app/models/billing.py

@@ -0,0 +1,47 @@
+from sqlalchemy import Column, Integer, String, DateTime, Float, Text, Index
+from app.models.base import BaseModel
+
+
+class BillingBatch(BaseModel):
+    __tablename__ = "billing_batches"
+
+    id = Column(Integer, primary_key=True, index=True)
+    batch_id = Column(String(100), unique=True, nullable=False, index=True)
+    status = Column(String(32), nullable=False)
+    total_files = Column(Integer, nullable=False, default=0)
+    successful_files = Column(Integer, nullable=False, default=0)
+    failed_files = Column(Integer, nullable=False, default=0)
+    started_at = Column(DateTime(timezone=True), nullable=False)
+    updated_at = Column(DateTime(timezone=True))
+    completed_at = Column(DateTime(timezone=True))
+    processing_time_seconds = Column(Float)
+    success_rate = Column(Float)
+    error_message = Column(Text)
+
+    __table_args__ = (
+        Index("ix_billing_batches_started_at", "started_at"),
+        Index("ix_billing_batches_updated_at", "updated_at"),
+        Index("ix_billing_batches_completed_at", "completed_at"),
+        {},
+    )
+
+
+class BillingBatchFile(BaseModel):
+    __tablename__ = "billing_batch_files"
+
+    id = Column(Integer, primary_key=True, index=True)
+    batch_id = Column(String(100), nullable=False, index=True)
+    file_no = Column(String(50), nullable=False, index=True)
+    status = Column(String(32), nullable=False)
+    error_message = Column(Text)
+    filename = Column(String(255))
+    size = Column(Integer)
+    started_at = Column(DateTime(timezone=True))
+    completed_at = Column(DateTime(timezone=True))
+
+    __table_args__ = (
+        Index("ix_billing_batch_files_batch_file", "batch_id", "file_no"),
+        {},
+    )
+
+