feat: add configuration module with env-based settings

src/fastapi_oidc_op/config.py

@@ -0,0 +1,36 @@
+# src/fastapi_oidc_op/config.py
+from enum import StrEnum
+
+from pydantic_settings import BaseSettings
+
+
+class StorageBackend(StrEnum):
+    SQLITE = "sqlite"
+    MONGODB = "mongodb"
+
+
+class Settings(BaseSettings):
+    model_config = {"env_prefix": "OIDC_OP_"}
+
+    # Core
+    issuer: str
+    debug: bool = False
+
+    # Storage
+    storage_backend: StorageBackend = StorageBackend.SQLITE
+
+    # SQLite
+    sqlite_path: str = "data/oidc_op.db"
+
+    # MongoDB
+    mongodb_uri: str = "mongodb://localhost:27017"
+    mongodb_database: str = "oidc_op"
+
+    # Management RP
+    manage_client_id: str = "manage-app"
+
+    # Magic links
+    invite_ttl: int = 86400  # seconds
+
+    # Theme
+    theme: str = "default"