2 files changed, 73 insertions, 0 deletions

diff --git a/src/config/loader.rs b/src/config/loader.rs
new file mode 100644
index 0000000..81a4351
--- /dev/null
+++ b/src/config/loader.rs
@@ -0,0 +1,70 @@
+use std::{env, path::PathBuf};
+
+use serde::Deserialize;
+
+use crate::{constants::*, errors::McError};
+
+#[allow(dead_code)]
+#[derive(Debug, Deserialize)]
+pub struct Config {
+    pub username: String,
+    pub uuid: String,
+    pub version: String,
+    pub java_path: String,
+    pub max_memory_mb: u32,
+    pub data_dir: PathBuf,
+    pub cache_dir: PathBuf,
+    pub config_dir: PathBuf,
+    #[serde(default)]
+    pub jvm_args: Vec<String>,
+}
+
+impl Config {
+    pub fn load() -> Result<Self, McError> {
+        let cfg_path = default_config_path()?;
+        let mut cfg: Config = if cfg_path.exists() {
+            let txt = std::fs::read_to_string(&cfg_path)?;
+            toml::from_str(&txt).map_err(|e| McError::Config(e.to_string()))?
+        } else {
+            Self::default()
+        };
+
+        if let Ok(v) = env::var("MC_USERNAME") {
+            cfg.username = v;
+        }
+        if let Ok(v) = env::var("MC_VERSION") {
+            cfg.version = v;
+        }
+        if let Ok(v) = env::var("MC_JAVA_PATH") {
+            cfg.java_path = v;
+        }
+        if let Ok(v) = env::var("MC_MAX_MEMORY_MB") {
+            cfg.max_memory_mb = v.parse().unwrap_or(cfg.max_memory_mb);
+        }
+
+        Ok(cfg)
+    }
+
+    fn default() -> Self {
+        let base =
+            directories::ProjectDirs::from("com", "example", "mccl").expect("platform dirs");
+
+        Self {
+            username: "Player".into(),
+            uuid: uuid::Uuid::new_v4().to_string(),
+            version: DEFAULT_VERSION.into(),
+            java_path: DEFAULT_JAVA_PATH.into(),
+            max_memory_mb: DEFAULT_MAX_MEMORY_MB,
+            data_dir: base.data_dir().into(),
+            cache_dir: base.cache_dir().into(),
+            config_dir: base.config_dir().into(),
+            jvm_args: vec![],
+        }
+    }
+}
+
+fn default_config_path() -> Result<PathBuf, McError> {
+    let base = directories::ProjectDirs::from("com", "example", "mccl")
+        .ok_or_else(|| McError::Config("cannot determine config dir".into()))?;
+    Ok(base.config_dir().join("config.toml"))
+}
diff --git a/src/config/mod.rs b/src/config/mod.rs
new file mode 100644
index 0000000..c5fc004
--- /dev/null
+++ b/src/config/mod.rs
@@ -0,0 +1,3 @@
+pub mod loader;
+
+pub use loader::Config;