feat(horismos): configuration loading and validation (P2-02)

crates/horismos/Cargo.toml

@@ -3,9 +3,17 @@ name = "horismos"
 version.workspace = true
 edition.workspace = true
 license.workspace = true
-description = "Configuration — Harmonia subsystem config loader"
+description = "Configuration loading and validation for Harmonia"
 
 [dependencies]
 harmonia-common.workspace = true
+figment = { workspace = true, features = ["toml", "env"] }
+serde.workspace = true
 snafu.workspace = true
 tracing.workspace = true
+
+[dev-dependencies]
+rstest.workspace = true
+tempfile = "3"
+serde_json.workspace = true
+figment = { workspace = true, features = ["toml", "env", "test"] }

crates/horismos/src/config.rs

@@ -0,0 +1,32 @@
+use serde::{Deserialize, Serialize};
+
+use crate::subsystems::{
+    AggeliaConfig, DatabaseConfig, EpignosisConfig, ErgasiaConfig, ExousiaConfig, KritikeConfig,
+    ParocheConfig, ProsthekeConfig, SyntaxisConfig, TaxisConfig, ZetesisConfig,
+};
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct Config {
+    #[serde(default)]
+    pub database: DatabaseConfig,
+    #[serde(default)]
+    pub exousia: ExousiaConfig,
+    #[serde(default)]
+    pub paroche: ParocheConfig,
+    #[serde(default)]
+    pub taxis: TaxisConfig,
+    #[serde(default)]
+    pub epignosis: EpignosisConfig,
+    #[serde(default)]
+    pub kritike: KritikeConfig,
+    #[serde(default)]
+    pub aggelia: AggeliaConfig,
+    #[serde(default)]
+    pub zetesis: ZetesisConfig,
+    #[serde(default)]
+    pub ergasia: ErgasiaConfig,
+    #[serde(default)]
+    pub syntaxis: SyntaxisConfig,
+    #[serde(default)]
+    pub prostheke: ProsthekeConfig,
+}

crates/horismos/src/error.rs

@@ -0,0 +1,20 @@
+use snafu::Snafu;
+
+#[derive(Debug, Snafu)]
+#[snafu(visibility(pub(crate)))]
+pub enum HorismosError {
+    #[snafu(display("configuration parse error: {source}"))]
+    ConfigParse {
+        #[snafu(source(from(figment::Error, Box::new)))]
+        source: Box<figment::Error>,
+        #[snafu(implicit)]
+        location: snafu::Location,
+    },
+
+    #[snafu(display("configuration validation failed: {message}"))]
+    Validation {
+        message: String,
+        #[snafu(implicit)]
+        location: snafu::Location,
+    },
+}