first commit

backend/app/core/errors.py

@@ -0,0 +1,23 @@
+from fastapi import FastAPI, Request
+from fastapi.responses import JSONResponse
+
+
+class AppError(Exception):
+    """Application-level error mapped to an HTTP response."""
+
+    def __init__(self, message: str, status_code: int = 400) -> None:
+        self.message = message
+        self.status_code = status_code
+        super().__init__(message)
+
+
+def register_exception_handlers(app: FastAPI) -> None:
+    @app.exception_handler(AppError)
+    async def handle_app_error(_request: Request, exc: AppError) -> JSONResponse:
+        return JSONResponse(status_code=exc.status_code, content={"detail": exc.message})
+
+    @app.exception_handler(Exception)
+    async def handle_unexpected_error(_request: Request, exc: Exception) -> JSONResponse:
+        if app.debug:
+            return JSONResponse(status_code=500, content={"detail": str(exc)})
+        return JSONResponse(status_code=500, content={"detail": "Internal server error"})