Merge pull request 'feat: implement custom error handling with AppError enum and update dependencies' (#4) from feature/error-handling into master

Reviewed-on: finwise/finewise#4

Cargo.lock

@@ -1276,7 +1276,7 @@ dependencies = [
  "tauri",
  "tauri-build",
  "tauri-plugin-opener",
- "thiserror 1.0.69",
+ "thiserror 2.0.18",
  "uuid",
 ]
 

src-tauri/Cargo.toml

@@ -25,7 +25,7 @@ serde_json = { workspace = true }
 sea-orm = { workspace = true }
 chrono = { workspace = true }
 migration = { path = "../crates/migration" }
-thiserror = "1"
+thiserror = "2"
 rust_decimal = "1"
 uuid = { version = "1", features = ["v4"] }
 

src-tauri/src/errors/app_error.rs

@@ -0,0 +1,84 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum AppError {
+    #[error("Database error: {0}")]
+    Database(#[from] sea_orm::DbErr),
+
+    #[error("Validation error: {0}")]
+    Validation(String),
+
+    #[error("Not found: {0}")]
+    NotFound(String),
+
+    #[error("Invalid amount: {0}")]
+    InvalidAmount(String),
+
+    #[error("Currency mismatch: expected {expected}, got {actual}")]
+    CurrencyMismatch { expected: String, actual: String },
+
+    #[error("IO error: {0}")]
+    Io(#[from] std::io::Error),
+
+    #[error("Serialization error: {0}")]
+    Serialization(#[from] serde_json::Error),
+
+    #[error("Internal error: {0}")]
+    Internal(String),
+
+    #[error("{0}")]
+    Other(String),
+}
+
+#[derive(serde::Serialize)]
+#[serde(tag = "kind", content = "message")]
+#[serde(rename_all = "camelCase")]
+enum ErrorKind {
+    Database(String),
+    Validation(String),
+    NotFound(String),
+    InvalidAmount(String),
+    CurrencyMismatch { expected: String, actual: String },
+    Io(String),
+    Serialization(String),
+    Internal(String),
+    Other(String),
+}
+
+impl serde::Serialize for AppError {
+    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+    where
+        S: serde::ser::Serializer,
+    {
+        let error_message = self.to_string();
+        let error_kind: ErrorKind = match self {
+            Self::Io(_) => ErrorKind::Io(error_message),
+            Self::Database(_) => ErrorKind::Database(error_message),
+            Self::Validation(_) => ErrorKind::Validation(error_message),
+            Self::NotFound(_) => ErrorKind::NotFound(error_message),
+            Self::InvalidAmount(_) => ErrorKind::InvalidAmount(error_message),
+            Self::CurrencyMismatch { expected, actual } => ErrorKind::CurrencyMismatch {
+                expected: expected.clone(),
+                actual: actual.clone(),
+            },
+            Self::Serialization(_) => ErrorKind::Serialization(error_message),
+            Self::Internal(_) => ErrorKind::Internal(error_message),
+            Self::Other(_) => ErrorKind::Other(error_message),
+        };
+        error_kind.serialize(serializer)
+    }
+}
+
+impl From<AppError> for String {
+    fn from(error: AppError) -> Self {
+        error.to_string()
+    }
+}
+
+impl From<rust_decimal::Error> for AppError {
+    fn from(error: rust_decimal::Error) -> Self {
+        AppError::InvalidAmount(error.to_string())
+    }
+}
+
+pub type CommandResult<T> = std::result::Result<T, AppError>;

src-tauri/src/errors/mod.rs

@@ -0,0 +1 @@
+pub mod app_error;

src-tauri/src/lib.rs

@@ -1,4 +1,5 @@
 mod db;
+mod errors;
 
 // Learn more about Tauri commands at https://tauri.app/develop/calling-rust/
 #[tauri::command]