refactor: Add JobSummary and Transaction models, client to get currency exchange rate

app/utils/csv_parser.py

@@ -4,10 +4,15 @@ from datetime import datetime
 from typing import Any, Dict, List
 from app.core.exceptions import InvalidCSVException
 
-REQUIRED_COLUMNS = {"transaction_id", "date", "amount", "category", "description"}
+REQUIRED_COLUMNS = {"txn_id", "date", "merchant", "amount"}
 
 
 def parse_and_validate_csv(content: bytes) -> List[Dict[str, Any]]:
+    """
+    Parses CSV content from bytes, validates headers, and checks field types.
+    Supports flexible mapping of common synonyms for headers.
+    Returns a list of dicts. Raises InvalidCSVException if the file is invalid.
+    """
     try:
         decoded = content.decode("utf-8")
     except UnicodeDecodeError as e:
@@ -16,32 +21,66 @@ def parse_and_validate_csv(content: bytes) -> List[Dict[str, Any]]:
     csv_file = io.StringIO(decoded)
     reader = csv.DictReader(csv_file)
 
-    # Map headers to predefined required cols
+    if not reader.fieldnames:
+        raise InvalidCSVException("CSV file is empty or missing headers")
+
     header_mapping = {}
     for actual_header in reader.fieldnames:
+        if not actual_header:
+            continue
         cleaned = actual_header.strip().lower()
-        if cleaned in REQUIRED_COLUMNS:
-            header_mapping[cleaned] = actual_header
-        elif cleaned == "id" and "transaction_id" not in header_mapping:
-            header_mapping["transaction_id"] = actual_header
 
+        # Map synonyms
+        if cleaned in {"txn_id", "transaction_id", "id"}:
+            header_mapping["txn_id"] = actual_header
+        elif cleaned == "date":
+            header_mapping["date"] = actual_header
+        elif cleaned in {"merchant", "description"}:
+            header_mapping["merchant"] = actual_header
+        elif cleaned == "amount":
+            header_mapping["amount"] = actual_header
+        elif cleaned == "currency":
+            header_mapping["currency"] = actual_header
+        elif cleaned == "category":
+            header_mapping["category"] = actual_header
+        elif cleaned in {"account_id", "account"}:
+            header_mapping["account_id"] = actual_header
+
+    # Verify all required columns are present in mapping
     missing = REQUIRED_COLUMNS - set(header_mapping.keys())
     if missing:
         raise InvalidCSVException(f"Missing required CSV columns: {', '.join(missing)}")
 
     parsed_rows = []
     for line_num, row in enumerate(reader, start=2):
-        t_id = row.get(header_mapping["transaction_id"])
+        txn_id = row.get(header_mapping["txn_id"])
         date_str = row.get(header_mapping["date"])
         amount_str = row.get(header_mapping["amount"])
-        category = row.get(header_mapping["category"])
-        description = row.get(header_mapping["description"])
+        merchant = row.get(header_mapping["merchant"])
 
-        if not all([t_id, date_str, amount_str, category, description]):
+        # Optional columns
+        currency = (
+            row.get(header_mapping.get("currency", ""))
+            if "currency" in header_mapping
+            else "INR"
+        )
+        category = (
+            row.get(header_mapping.get("category", ""))
+            if "category" in header_mapping
+            else None
+        )
+        account_id = (
+            row.get(header_mapping.get("account_id", ""))
+            if "account_id" in header_mapping
+            else None
+        )
+
+        if not all([txn_id, date_str, amount_str, merchant]):
             raise InvalidCSVException(
                 f"Row {line_num}: Empty values are not allowed in required fields"
             )
 
+        # Validate amount
         try:
             amount = float(amount_str.strip())
         except ValueError as e:
@@ -49,6 +88,7 @@ def parse_and_validate_csv(content: bytes) -> List[Dict[str, Any]]:
                 f"Row {line_num}: Invalid amount '{amount_str}'. Must be a number."
             ) from e
 
+        # Validate date (supporting multiple formats)
         parsed_date = None
         for fmt in ("%Y-%m-%d", "%m/%d/%Y", "%d-%m-%Y", "%Y/%m/%d"):
             try:
@@ -64,11 +104,13 @@ def parse_and_validate_csv(content: bytes) -> List[Dict[str, Any]]:
 
         parsed_rows.append(
             {
-                "transaction_id": t_id.strip(),
+                "txn_id": txn_id.strip(),
                 "date": parsed_date.isoformat(),
                 "amount": amount,
-                "category": category.strip(),
-                "description": description.strip(),
+                "merchant": merchant.strip(),
+                "currency": currency.strip() if currency else "INR",
+                "category": category.strip() if category else None,
+                "account_id": account_id.strip() if account_id else None,
             }
         )