5 files changed, 91 insertions, 3 deletions
diff --git a/systems/_config/Cargo.toml b/systems/_config/Cargo.toml
index afc1d81..11e08f3 100644
--- a/systems/_config/Cargo.toml
+++ b/systems/_config/Cargo.toml
@@ -5,3 +5,7 @@ version.workspace = true
 
 [dependencies]
 serde.workspace = true
+serde_json.workspace = true
+serde_yaml.workspace = true
+thiserror.workspace = true
+toml.workspace = true
diff --git a/systems/_config/src/error.rs b/systems/_config/src/error.rs
new file mode 100644
index 0000000..791aab2
--- /dev/null
+++ b/systems/_config/src/error.rs
@@ -0,0 +1,19 @@
+use std::path::PathBuf;
+
+#[derive(thiserror::Error, Debug)]
+pub enum ConfigError {
+    #[error("Failed to read config file: {0}")]
+    ConfigReadFailed(#[source] std::io::Error),
+
+    #[error("Failed to write config file: {0}")]
+    ConfigWriteFailed(#[source] std::io::Error),
+
+    #[error("Config file not found: {0}")]
+    FileNotFound(PathBuf),
+
+    #[error("IO error: {0}")]
+    Io(#[source] std::io::Error),
+
+    #[error("Other error: {0}")]
+    Other(String),
+}
diff --git a/systems/_config/src/lib.rs b/systems/_config/src/lib.rs
new file mode 100644
index 0000000..26fe31a
--- /dev/null
+++ b/systems/_config/src/lib.rs
@@ -0,0 +1,2 @@
+pub mod error;
+pub mod rw;
diff --git a/systems/_config/src/main.rs b/systems/_config/src/main.rs
deleted file mode 100644
index e7a11a9..0000000
--- a/systems/_config/src/main.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-fn main() {
-    println!("Hello, world!");
-}
diff --git a/systems/_config/src/rw.rs b/systems/_config/src/rw.rs
new file mode 100644
index 0000000..36ea00c
--- /dev/null
+++ b/systems/_config/src/rw.rs
@@ -0,0 +1,66 @@
+use crate::error::ConfigError;
+use serde::{Deserialize, Serialize};
+use std::path::Path;
+
+pub async fn read_config<C>(path: impl AsRef<Path>) -> Result<C, ConfigError>
+where
+    C: for<'a> Deserialize<'a>,
+{
+    let path_ref = path.as_ref();
+    let ext = path_ref
+        .extension()
+        .and_then(|ext| ext.to_str())
+        .unwrap_or("json");
+    let format = ext_fmt(&ext.to_lowercase());
+
+    let content = std::fs::read_to_string(path_ref).map_err(ConfigError::ConfigReadFailed)?;
+
+    match format {
+        Format::Yaml => {
+            serde_yaml::from_str(&content).map_err(|e| ConfigError::Other(e.to_string()))
+        }
+        Format::Toml => toml::from_str(&content).map_err(|e| ConfigError::Other(e.to_string())),
+        Format::Json => {
+            serde_json::from_str(&content).map_err(|e| ConfigError::Other(e.to_string()))
+        }
+    }
+}
+
+pub async fn write_config<C>(path: impl AsRef<Path>, config: &C) -> Result<(), ConfigError>
+where
+    C: Serialize,
+{
+    let path_ref = path.as_ref();
+    let ext = path_ref
+        .extension()
+        .and_then(|ext| ext.to_str())
+        .unwrap_or("json");
+    let format = ext_fmt(&ext.to_lowercase());
+
+    let content = match format {
+        Format::Yaml => {
+            serde_yaml::to_string(config).map_err(|e| ConfigError::Other(e.to_string()))?
+        }
+        Format::Toml => toml::to_string(config).map_err(|e| ConfigError::Other(e.to_string()))?,
+        Format::Json => {
+            serde_json::to_string_pretty(config).map_err(|e| ConfigError::Other(e.to_string()))?
+        }
+    };
+
+    std::fs::write(path_ref, content).map_err(ConfigError::ConfigWriteFailed)
+}
+
+enum Format {
+    Yaml,
+    Toml,
+    Json,
+}
+
+fn ext_fmt(ext: &str) -> Format {
+    match ext {
+        "yaml" | "yml" => Format::Yaml,
+        "toml" | "tml" => Format::Toml,
+        "json" => Format::Json,
+        _ => Format::Json,
+    }
+}