Rewrite Curator in Rust with an egui GUI

src/core/error.rs

@@ -0,0 +1,33 @@
+//! The error type shared by the core modules.
+
+use std::io;
+
+/// Everything a core operation can fail with. The `Display` text is shown to the
+/// user as-is, so validation messages are written in Czech like the rest of the UI.
+#[derive(Debug, thiserror::Error)]
+pub enum CoreError {
+    /// Invalid input (bad year, empty title, unknown 3D format, …).
+    #[error("{0}")]
+    Invalid(String),
+    /// The target already exists and the caller asked not to overwrite it.
+    #[error("{0}")]
+    Exists(String),
+    /// Something expected on disk is missing.
+    #[error("{0}")]
+    NotFound(String),
+    /// A remote service (TMDb, ČSFD, Jellyfin) failed.
+    #[error("{0}")]
+    Remote(String),
+    #[error(transparent)]
+    Io(#[from] io::Error),
+    #[error(transparent)]
+    Json(#[from] serde_json::Error),
+}
+
+impl CoreError {
+    pub fn invalid(msg: impl Into<String>) -> Self {
+        Self::Invalid(msg.into())
+    }
+}
+
+pub type CoreResult<T> = Result<T, CoreError>;