Allow etc system-wide config (#137)

 Support /etc/ system-wide configuration

odilia/src/state.rs

@@ -37,6 +37,13 @@ pub struct ScreenReaderState {
 	pub cache: Arc<Cache>,
 }
 
+enum ConfigType {
+	CliOverride,
+	XDGConfigHome,
+	Etc,
+	CreateDefault,
+}
+
 impl ScreenReaderState {
 	#[tracing::instrument]
 	pub async fn new(
@@ -54,25 +61,47 @@ impl ScreenReaderState {
 
 		tracing::debug!("Reading configuration");
 
-		let config_path = if config_override.is_none() {
-			let xdg_dirs = xdg::BaseDirectories::with_prefix("odilia").expect(
-            "unable to find the odilia config directory according to the xdg dirs specification",
-        	);
-			let config_path = xdg_dirs.place_config_file("config.toml").expect(
-			"unable to place configuration file. Maybe your system is readonly?",
-			);
+		// In order of prioritization, do configuration via cli, then XDG_CONFIG_HOME, then /etc/,
+		// Otherwise create it in XDG_CONFIG_HOME
+		let config_type = if config_override.is_some() {
+			ConfigType::CliOverride
 
-			if !config_path.exists() {
-				fs::write(&config_path, include_str!("../config.toml"))
-					.expect("Unable to copy default config file.");
-			}
-			config_path.to_str().ok_or(ConfigError::PathNotFound)?.to_owned()
+		// First check makes sure unwrap is safe
+		} else if xdg::BaseDirectories::with_prefix("odilia").is_ok()
+			&& xdg::BaseDirectories::with_prefix("odilia")
+				.expect("This error should never occur")
+				.find_config_file("config.toml")
+				.is_some()
+		{
+			ConfigType::XDGConfigHome
+		} else if std::path::Path::new("/etc/odilia/config.toml").exists() {
+			ConfigType::Etc
 		} else {
-			config_override
+			ConfigType::CreateDefault
+		};
+
+		let config_path = match config_type {
+			ConfigType::CliOverride => config_override
 				.expect("Config override was provided but is None")
 				.to_str()
 				.ok_or(ConfigError::PathNotFound)?
-				.to_owned()
+				.to_owned(),
+			ConfigType::XDGConfigHome | ConfigType::CreateDefault => {
+				let xdg_dirs = xdg::BaseDirectories::with_prefix("odilia").expect(
+					"unable to find the odilia config directory according to the xdg dirs specification",
+				);
+
+				let config_path = xdg_dirs.place_config_file("config.toml").expect(
+					"unable to place configuration file. Maybe your system is readonly?",
+				);
+
+				if !config_path.exists() {
+					fs::write(&config_path, include_str!("../config.toml"))
+						.expect("Unable to copy default config file.");
+				}
+				config_path.to_str().ok_or(ConfigError::PathNotFound)?.to_owned()
+			}
+			ConfigType::Etc => "/etc/odilia/config.toml".to_owned(),
 		};
 
 		tracing::debug!(path=%config_path, "loading configuration file");